Antimalarial Potential of Phragmanthera capitata : An Insight Into the Activity of Its Extracts and Isolated Compounds

Abstract

Objective

This study aimed to evaluate the antimalarial activity of the extracts and isolated compounds from the stem of Phragmanthera capitata.

Methods

Aqueous and methanol extracts were prepared from the stem of the plant. The methanol extract was purified via column chromatography to yield friedelin, friedelinol, β-sitosterol and daucosterol. The in vitro anti-plasmodial activity of the extracts and isolated compounds was evaluated against chloroquine-sensitive (3D7) and resistant (Dd2) strains of P. falciparum using the SYBR Green assay and, in vivo antimalarial activity via the Peters’ and Rane’s tests.

Results

The methanol extract demonstrated superior activity over the aqueous extract, with IC₅₀ values of 0.84 (3D7) and 1.92 µg/mL (Dd2) in the in vitro antiplasmodial assay. Similarly, daucosterol was the most active compound among the isolated compounds with IC₅₀ values of 0.84 (3D7) and 2.05 μg/mL (Dd2). The aqueous and the methanol extracts showed comparable suppressive activities in the Peters’ assay with 88% and 89% parasitaemia suppression, respectively. The aqueous extract was more active in the Rane’s curative assay, with 89 % parasitaemia suppression. Friedelin and β-sitosterol displayed similar and remarkable curative potential in the Rane’s assay with % parasitaemia suppression of 85.66 and 86.49, respectively.

Conclusion

This study validates the Phragmanthera capitata extracts and isolated compounds as antimalarial agents, rationalising the traditional use of the plant to treat malaria. Future work could consider development into antimalarial products, which would contribute to SDG 3 and the Universal Health coverage.

Keywords

malaria antiplasmodial phytochemistry african mistletoe traditional medicine daucosterol

1. Introduction

Medicinal plants have long played a crucial role in healthcare systems worldwide. About 80% of the global population relies on herbal remedies to address some of their health needs.¹ Numerous studies have scientifically validated the medicinal properties of some medicinal plants, while attributing their therapeutic potential to their diverse phytochemical constituents.² Many of these phytochemicals have been successfully developed into drugs used globally for the treatment of various diseases. Notable examples include artemisinin, derived from Artemisia annua and quinine from Cinchona species, widely used in the treatment of malaria. Recent investigations further underscore the considerable potential of medicinal plants as reservoirs of antimalarial phytoconstituents, with the application of in vitro assays and multi-target screening strategies enhancing the discovery of promising drug leads.^3,4 Nevertheless, there are several medicinal plants widely employed traditionally without empirical evidence to support their efficacy and safety, highlighting a critical need for their scientific validation.⁵ One such plant is Phragmanthera capitata (Spreng.) Balle.

It is a hemiparasitic epiphyte in the Loranthaceae family, widely distributed across tropical Africa. It is locally known in Ghana by the Akans as “Nkranpan”. P. capitata is known to parasitise various economically important plants, such as cocoa, pear, rubber, as well as orange.⁶ The stem and leaves are traditionally employed in treating diseases such as hypertension, diabetes, wounds and malaria.⁷ Previous studies have reported a range of biological properties of the aerial part of the plant, including anti-inflammatory, antioxidant,⁸ hematopoietic potentiating,⁹ antibacterial and antifungal properties.¹⁰ The leaf extract has immunomodulatory and hypolipidemic effects.¹¹ The methanol leaf extract also demonstrated promising antiplasmodial activity against the chloroquine-sensitive strain (NF54) with an IC₅₀ of 4.75 μg/mL.¹² Phytochemical studies have identified several constituents from the plant. Njoya et al¹³ isolated 7β,15α-dihydroxy-3β-palmitatelup-20(29)-ene, 3-O-β-D-glucopyranosyl-28-hydroxy-α-amyrin, and apigenin-8-C-β-D-glucopyranoside from the methanolic leaf extract. Additionally, GC-MS analysis of the ethanolic leaf extract revealed the presence of compounds such as 3-H-pyrazol-3-1, decanoic acid, n-hexadecanoic acid, lupeol, and chilosyphone.¹⁴ Despite the widespread use of the plant stem in treating malaria, there is no scientific evidence to support this claim. Additionally, the compounds responsible for its potential antimalarial activity remains unknown. This gap is significant, given the disproportionate and persistent burden of malaria in Africa, particularly in countries like Ghana, which contributed 2.5% of global cases.¹⁵ This study therefore, evaluated the antimalarial activity of the stem extracts of P. capitata (parasitic on Theobroma cacao), together with isolated compounds, using in vivo and in vitro methods. This study contributes to the global fight against malaria by exploring plant-based antimalarial treatments, and thus aligns with the United Nations Sustainable Development Goal 3 (SDG 3) -Good Health and Well-being.

2. Materials and Methods

This study was an experimental laboratory-based investigation conducted to evaluate the antimalarial activity of extracts, fractions, and isolated compounds from Phragmanthera capitata. It was carried out at the Pharmacognosy and Pharmacology Departments of Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana, and the Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana, between March 2023 and December 2025.

2.1. Reagents, Solvents, and Equipment

Analytical grade methanol (MeOH), ethyl acetate (EtOAc), chloroform (CHCl₃), and petroleum ether, employed in this study were acquired from UK chemicals (Kumasi, Ghana). Deuterated solvents (Chloroform and Dimethyl sulphoxide (DMSO)) were obtained from Sigma Aldrich (Spruce Street, St. Luis, USA). Silica gel (mesh size 70-230) as well as Sephadex LH-20 beads were bought from Sigma Aldrich (Spruce Street, St. Luis, MO 63178 USA). Artesunate, DMSO, L-glutamine, Albumax, Hypoxanthine, Sodium bicarbonate, RPMI1640 powder (GIBCO), RPMI 1640 medium, Glucose, Albumax, Hypoxanthine, SYBR Green 1 (10000 in DMSO), Immersion oil, Giemsa stain, Triton X-100, were obtained from Sigma Aldrich.

2.2. Plant Material Collection and Processing

Phragmanthera capitata stem parasitic on cocoa was harvested in March 2023 at the Agriculture Reserve at Kwame Nkrumah University of Science and Technology (6°40′47.3″N 1°33′03.4″W). It was authenticated by Mr. Clifford Asare of the Department of Herbal Medicine, KNUST. A voucher specimen with the number KNUST/HM1/2023/SB028 was stored at the herbarium of the Faculty of Pharmacy and Pharmaceutical Sciences, KNUST. The stem was washed under running water, cut into smaller sizes, and air dried under shade for 6 days with occasional turning. The air-dried material was ground into a coarse powder with a mechanical grinder.

2.3. Extraction of Plant Material

About 500 g of the dried powdered material was boiled in 1 L of water for 30 minutes. It was subsequently allowed to cool and filtered through cotton wool. The filtrate was then filtered with Whatman No. 1 filter paper (Whatman®, England). The final filtrate was freeze-dried and kept in a desiccator until required. This extraction procedure was adopted from Komlaga et al.¹⁶

The extraction procedure employed for the purpose of fractionation and isolation of plant constituents, was adopted from Baah et al.¹⁷ Two (2 kg) kilograms of the powdered material was repeatedly extracted with absolute methanol over 72 hrs. The extract was strained through cotton wool and filtered using No. 1 Whatman filter paper (Whatman®, England) and the filtrate pooled together. It was concentrated using the rotary evaporator, and the residue kept in a desiccator until required for use.

2.4. Preliminary Phytochemical Screening

The aqueous and alcoholic stem extracts of P. capitata was subjected to general qualitative phytochemical screening using standard methods.¹⁸

2.5. Fractionation of Stem Extract of P. capitata

The crude methanol extract was subsequently fractionated on silica gel (70-230 mesh size), eluting gradiently with petroleum ether, ethyl acetate and methanol to afford three organic fractions.¹⁷

The ethyl acetate fraction of P. capitata was identified as the most active (Supplementary material) and was selected for sub-fractionation and isolation of its constituents.

Briefly, about 30 g of the ethyl acetate fraction was fractionated on a gravity-fed column (silica gel 70-230 mesh), and gradiently eluted with petroleum ether, ethyl acetate and methanol to afford 43 fractions. These fractions were further bulked into seven fractions (PC1–PC7) based on their TLC profiles.

PC1 was fractionated gradiently (100% Pet – 70% Pet: 30% EtoAc) to yield three bulk fractions (PC1a – PC1c). Bulk fraction PC1b was purified by washing with petroleum ether to obtain PA1 (25 mg) as a white amorphous powder. Bulked fraction PC1c was recrystallised in petroleum ether to obtain PA2 (56 mg) as white crystals.

PC2 (Pet. Ether: EtOAc, 9:1) was gradiently eluted on silica (70-230 mesh) to afford four bulked fractions (PC2a–PC2d). Bulked fraction PC2b was recrystallised in petroleum ether to obtain PA3 (11 mg) as white crystals. PC6 was isocratically eluted on Sephadex LH-20 with CHCl₃ and MeOH (1:1) to obtain PA4 (15 mg) as a white amorphous powder.

2.6. In vitro Studies

2.6.1. Antiplasmodial Activity of Extracts and Isolated Compounds

The test samples (extracts and isolated constituents) were assayed for in vitro antiplasmodial activity using the SYBR green method.¹⁹ It was done against the chloroquine-sensitive (3D7) and resistant (Dd2) strains of P. falciparum at the Department of Epidemiology, Noguchi Memorial Institute for Medical Research, University of Ghana. Stock solutions of extracts (200 μg/mL) were prepared in 0.5% DMSO. Each 200 µL-capacity well contained 100 µL of culture, with a parasitaemia of 1% and a haematocrit level of 2 %. Test substances were prepared in a two-fold dilution to obtain 8 dose titrations from 100 to 0.78 µg/mL. Negative control wells had no drug/inhibitor while the positive control wells received Artesunate. The tests were conducted in triplicate. The plates were incubated at 37 °C for 48 hours. After the incubation, 100 µL of SYBR green I in lysis buffer was added to the contents of the wells.

The mixture was vortexed and further incubated for 30 minutes at room temperature (25 °C). Absorbance was read with a multi-well plate reader (Guava Easycyte HT Facs machine, Millipore, USA) at excitation and emission wavelengths of 485 and 530 nm, respectively. IC₅₀ was calculated using GraphPad (Version 8.0.2).²⁰

2.6.2. Cytotoxicity Study

The cytotoxicity of the test samples was assessed on human erythrocytes using the MTT assay.²⁰ Samples were tested at a concentration range of 100 µg/mL to 1.5 µg/mL in 96-well plates (200 µL). The wells were seeded with 90 µL of packed red blood cells (RBCs) in RPMI 1640 medium (haematocrit of 2.0%), and approximately 10 µL of the different concentrations of the test samples were added and vortexed. The mixture was incubated for 72 hours at 37 °C. At the end of the incubation, 20 µL of 7.5 mg/mL MTT was added and further incubated for 4 hours. The supernatant was aspirated using a Pasteur pipette, and the formazan crystals were dissolved in 150 µL of acidified isopropanol. The negative control wells (without the inhibitor/extract) were treated similarly. Absorbance was measured at 540 nm. The concentration of extracts that caused a 50% reduction in cell viability (CC₅₀) was calculated.²¹

2.7. In vivo Studies

2.7.1. Experimental Animals

Mixed sexes of Sprague Dawley rats and Swiss albino mice were obtained from the Centre for Plant Medicine Research (CPMR), Mampong, Ghana. The animals were housed and allowed to acclimatise at the animal house of the Department of Pharmacology at KNUST for 7 days. They were subjected to a 12:12 dark-to-light cycle and offered unrestricted access to clean water and a pellet diet. The in vivo experiments were conducted following the Institution’s standard operating procedures. Guidelines for the Helsinki Declaration for treating experimental animals were meticulously observed.²² All animal experiments were conducted and reported in accordance with the ARRIVE 2.0 guidelines.²³ The protocol for the animal studies was approved by the Animal Research Ethics Committee at KNUST (ID KNUST 0081).

2.7.2. Acute Toxicity Test of Extracts

The limit test was employed to assess the acute toxicity of the aqueous and alcoholic extracts.²⁴ Three (3) female Sprague Dawley rats were put into two groups. Each group was dosed separately with a single 2000 mg/kg body weight of the aqueous and methanolic extract in turn. This was achieved using a stomach tube after overnight food starvation with unrestricted access to water.

Feeding was delayed for another 3 hours, during which the rats were monitored at 30-minute intervals for the first 1 hour. They were then monitored occasionally for the next 24 hours, with specific attention paid to the first 4 hours. Subsequently, observation was made daily for the next 13 days for indicators of toxicity such as rigidity, sleepiness, abnormal secretion, hair erection and death.

2.7.3. Parasite Passage and Inoculation

Chloroquine-sensitive ANKA P. berghei were passaged in Swiss albino rats used as donors. Parasitised donor rats were first anaesthetised with ketamine (100 mg/kg, intraperitoneal) to achieve a surgical plane of anesthesia, as confirmed by loss of pedal withdrawal reflex and subsequently euthanised via cervical dislocation and the blood collected into heparinised vacutainer tubes via cardiac puncture.²⁵ The infected blood was diluted with physiological saline (0.9%) to 5 × 10⁷ parasite-infected RBC per millilitre of blood. Mice were then inoculated with 0.2 mL diluted blood containing approximately 1 x 10⁷ infected RBC through the intraperitoneal route.

2.7.4. Peters’ Four-Day Suppressive Test

Suppressive antimalarial activities of test samples were evaluated as described.^26,27 Infected mice were randomly divided into 10 groups of 5. Eight (8) groups were treated with extracts (aqueous or methanol) at doses of 50, 100, 200 and 400 mg/kg/day for 4 consecutive days. The positive control group received 4 mg/kg/day of artesunate, and the negative control group, 2 mL of normal saline/day. On the 4th day (96 hours post-inoculation), thin blood smears were prepared using blood from the tail vein of mice. Parasitaemia was determined by counting the number of parasitised red blood cells out of the total red blood cells in five randomly chosen fields of the slide using a light microscope (Leica DM750, Wetzlar, Germany). The weights and temperature of mice were taken before treatment and on the 4^th day post-infection using a digital balance and digital anal thermometer, respectively. The infected mice were tracked for mortality for 30 days, and the number of days it took a mouse to die (if any) was recorded. Percentage parasitaemia suppression and survival time were determined as previously described.²⁸

2.7.5. Rane’s Curative Test

The curative properties of the aqueous and methanol extracts was evaluated following a previously described protocol.⁴ Following parasitaemia establishment (72 hrs post-parasite inoculation), mice were randomly divided into groups of 5. The extract treated groups were dosed with 50, 100, 200 and 400 mg/kg/day of the crude extracts whiles the compound treated groups were dosed with 3, 10 and 30 mg/kg/day of isolated compounds for 4 days.

The control groups also received 4 mg/kg/day of artesunate (positive control) and 2 mL of normal saline (negative control) daily for 4 consecutive days. On day 7 post-inoculation, parasitaemia was determined from thin blood smears, and the percentage parasite suppression was estimated. The body weights and temperature of the mice were determined prior to and after treatment. The animals were monitored for survival for 30 days post-treatment. Survival curves were constructed, and the median survival time calculated.

2.8. Data Analysis

Data was analysed using GraphPad Prism. (GraphPad Software version 8.0.2, San Diego, CA, USA) and presented as mean ± SD. Comparisons were made against negative controls as well as among treatment groups using a one-way analysis of variance (ANOVA) followed by Dunnett’s multiple comparison tests. Body weight changes were compared using two-way ANOVA followed by Dunnett’s multiple comparison tests. The results were considered statistically significant at a 95% confidence level.

3. Results

3.1. Qualitative Phytochemical Screening

Qualitative phytochemical screening of the aqueous and methanolic extracts of P. capitata revealed the presence of key secondary metabolites, including alkaloids, tannins, triterpenoids, phytosterols and flavonoids. Both extracts exhibited similar phytochemical profiles, with no qualitative differences observed (Table 1).

Table 1.

Qualitative Phytochemical Screening of Plant Extracts

Phytoconstituent	PCA	PCM
Alkaloids	+	+
Tannins	+	+
Flavonoids	+	+
Saponins	+	+
Coumarins	+	+
Triterpenoids	+	+
Phytosterols	+	+
Reducing sugars	+	+

Key: + = detected, PCA = aqueous stem extract of P. capitata, PCM = methanol stem extract of P. capitata.

3.2. Isolated Compounds

PA1 was obtained as a white crystalline solid, with a melting point of 262-266 °C. It was established as C₃₀H₅₂O by the MS data with a peak at m/z 255.03 (M+H)⁺ and a proposed molecular weight of 254. The IR absorption bands at 2926.91 cm^-1 and 2869.30 cm^-1 (C-H stretch) and 1713.91 cm^-1 (C=O). Coupled with the NMR data (¹³C, HSQC, COSY and HMBC), PA1 was identified as Friedelan-3-one, trivially known as friedelin (Figure 1). ¹H-NMR (500 MHz, CDCl₃) δ: 2.28 (1H, s, H-4), 1.39 (1H, dd, H-8), 1.53 (1H, m, H-10), 1.56 (1H, s, H-18), 0.88 (3H, d, H-23), 0.72 (3H, s, H-24), 0.87 (3H, s, H-25), 1.01 (3H, s, H-26), 1.05 (3H, s, H-27), 1.18 (3H, s, H-28), 1.0 (3H, s, H-29), 0.96 (3H, s, H-30). ¹³C-NMR (500 MHz, CDCl₃) δ: 22.3 (C-1), 41.5 (C-2), 213.3 (C-3), 58.2 (C-4), 42.2 (C-5), 41.3 (C-6), 18.2 (C-7), 53.1 (C-8), 37.4 (C-9), 59.5 (C-10), 35.6 (C-11), 30.5 (C-12), 39.7 (C-13), 38.3 (C-14), 32.4 (C-15), 36.0 (C-16), 30.0 (C-17), 42.8 (C-18), 35.3 (C-19), 28.2 (C-20), 32.8 (C-21), 39.2 (C-22), 6.8 (C-23), 14.7 (C-24), 18.0 (C-25), 20.3 (C-26), 18.7 (C-27), 32.1 (C-28), 35.0 (C-29), 31.8 (C-30).

Figure 1.

Isolated compounds from the stem of P. capitata

PA2 was obtained as a white amorphous solid, with a melting point of 137-140°C. It was established as C₂₉H₅₀O by the MS data with a peak at m/z 414.258 (M+H)⁺ and a proposed molecular weight of 414.7066. The FTIR spectrum displayed absorption bands (V_max cm^-1) at 2934.65 and 2855.02 cm^-1 (C-H absorption), cyclic methylene C-H stretches at 1463.73. A weak band at 3418.88 cm^-1 attributed to the OH group. Together with the NMR data, PA2 was identified of as (3β)-Stigmast-5-en-3-ol, trivially known as β-Sitosterol (Figure 1). ¹H-NMR (500 MHz, CDCl₃) δ: 5.35 (1H, d, H-6), 3.52 (1H, m, H-3), 2.29 (1H, m, H-4), 1.55 (1H, m, H-2), 1.05 (1H, H-19), 0.93 (1H, d, H-21), 0.86 (1H, H-27), 0.84 (1H, H-26), 0.82 (1H, H-29), 0.68 (1H, H-18). ¹³C-NMR (500 MHz, CDCl₃) δ: 37.4 (C-1), 21.2 (C-2), 71.9 (C-3), 42.5 (C-4), 140.9 (C-5), 121.9 (C-6), 32.0 (C-7), 31.8 (C-8), 50.3 (C-9), 36.7 (C-10), 21.2 (C-11), 39.9 (C-12), 42.5 (C-13), 56.9 (C-14), 24.4 (C-15), 28.4 (C-16), 56.2 (C-17), 12.0 (C-18), 19.9 (C-19), 36.3 (C-20), 18.9 (C-21), 34.1 (C-22), 26.2 (C-23), 46.0 (C-24), 29.3 (C-25), 19.6 (C-26), 19.1 (C-27), 23.2 (C-28), 12.1 (C-29).

PA3 was obtained as a white amorphous powder, with a melting point of 282-296 °C. It was established as C₃₀H₅₂O by the MS data with a peak at m/z 255.03 (M+H)⁺ and a proposed molecular weight of 254. The IR spectrum of PA3 showed absorption bands (V_max) for hydroxyl functionality at 3348.17 and others at 2935.12, 2865.76, 1463.78 and 1367.19 cm^-1. This differed from of PA1 by the presence of the hydroxyl (OH) group. Isolate PA3 was identified as friedelin/friedelinol (Figure 1). ¹³C-NMR (500 MHz, CDCl₃) δ: 22.4/16.5 (C-1), 41.4/36.2 (C-2), 213.4/72.9 (C-3), 49.3 (C-4), 42.3/38.4 (C-5), 41.9 (C-6), 18.1/17.7 (C-7), 53.3/53.3 (C-8), 37.6/37.2 (C-9), 59.6/61.5 (C-10), 35.8/35.7 (C-11), 30.8/30.7 (C-12), 39.8/38.5 (C-13), 38.5/39.8 (C-14), 32.6/32.9 (C-15), 36.2/36.2 (C-16), 30.1/30.1 (C-17), 43.0/42.9 (C-18), 35.3/35.5 (C-19), 28.3 (C-20), 32.9/33.0 (C-21), 39.4/39.4 (C-22), 7.0/11.8 (C-23), 14.8/15.9 (C-24), 18.1/18.4 (C-25), 20.4/20.3 (C-26), 18.8/18.8 (C-27), 32.2/32.2 (C-28), 35.3/35.2 (C-29), 31.9 (C-30).

PA4 was obtained as a white crystalline solid, with a melting point of 270-278°C. It was established as C₃₅H₆₀O₆ by the MS data with a peak at m/z 414.258 (M+H)⁺ and a proposed molecular weight of 414.7066. The IR spectrum showed peaks at 3340 cm^-1 (–OH), at 1720 cm^-1 (C=O) and absorption bands at 2900–2850 cm^-1 indicating the presence of possible methylene and methine groups. Analysis of the aforementioned, coupled with the NMR data, led to the identification of PA4 as β-sitosterol-3-O-β-D-glucopyranoside, trivially known as Daucosterol. Isolate PA4 was identified as Daucosterol (Figure 1). ¹³C-NMR (500 MHz, CDCl₃) δ: 39.71 (C-1), 25.90 (C-2), 79.42 (C-3), 42.31 (C-4), 140.91 (C-5), 121.67 (C-6), 31.89 (C-7), 33.82 (C-8), 50.08 (C-9), 33.82 (C-10), 21.07 (C-11), 39.21 (C-12), 42.31 (C-13), 56.66 (C-14), 24.33 (C-15), 28.56 (C-16), 56.30 (C-17), 12.13 (C-18), 19.40 (C-19), 36.68 (C-20), 19.57 (C-21), 35.96 (C-22), 29.73 (C-23), 45.61 (C-24), 29.17 (C-25), 19.57 (C-26), 19.08 (C-27), 23.08 (C-28), 12.13 (C-29), 101.26 (C-1′), 73.92 (C-2′), 77.42 (C-3′), 70.55 (C-4′), 77.20 (C-5′), 61.55 (C-6′).

3.3. In vitro Antiplasmodial Activity and Cytotoxicity of Extracts and Isolated Compounds

The aqueous and methanol crude stem extracts demonstrated promising antiplasmodial activity against the 3D7 and Dd2 strains of P. falciparum (Table 2). The extracts demonstrated superior activity against the 3D7 strain relative to the resistant strain. Additionally, the methanol extract demonstrated superior antiplasmodial activity compared to the aqueous extract against both strains, with the highest activity recorded at an IC₅₀ of 0.84±0.07 and 1.92±0.10 µg/ml against the 3D7 and Dd2 strains, respectively. The aqueous and methanol extracts did not show toxicity against RBCs (Table 2). The highest CC₅₀ was seen with the methanol extract of P. capitata, higher compared to the aqueous extract. It is also noteworthy that the aqueous and methanol extracts of P. capitata were less cytotoxic compared to the positive control (Table 2). All tested extracts recorded selectivity indices greater than 2 with the methanol extract recording a higher selectivity index than the aqueous extract. The isolated compounds demonstrated varying levels of activity against both strains. Daucosterol demonstrated the highest activity, with IC₅₀ values of 0.84 ± 0.002 (3D7) and 2.6 ± 0.00009 µM (Dd2). Generally, the compounds demonstrated a better anti-plasmodial activity against the chloroquine sensitive (3D7) P. falciparum than the chloroquine resistant Dd2 P. falciparum strain (Table 2). The crude methanol extract demonstrated superior antiplasmodial activity compared to the isolated compounds but for daucosterol, which showed similar activity to the methanol extract.

Table 2.

In vitro Antiplasmodial Activity and Cytotoxicity of PCA, PCM and Isolates

EXTRACTS/DRUG	IC₅₀ (3D7)	IC₅₀ (Dd2)	CC₅₀ (μg/ml)	SSI CC₅₀/IC_{50 of 3D7}
PCA	2.39±0.11	2.43±0.06	90.8	37.9
PCM	0.84±0.07	1.92±0.10	197	>100
Friedelin	2.19±0.65	4.58 ± 0.64
Β-Sitosterol	14.5±1.20	26.4 ± 1.40
Friedelinol/Friedelin	46.08±1.55	46.92 ± 5.32
Daucosterol	0.84±0.002	2.05 ± 0.003
ART	0.20±0.00001	2.6±0.00009	>100	>100

PCA = Aqueous extract of P. capitata, PCM = methanol extract of P. capitata 3D7 = Chloroquine sensitive strain, Dd2 = Chloroquine resistant strain, ART = Artesunate, SSI = selectivity index.

3.4. Acute Oral Toxicity

The aqueous and alcoholic extract at a single oral dose of 2000 mg/kg caused no observable physical or behavioural changes such as sleepiness, rigidity, diarrhoea, hair erection and abnormal secretion for 24 hours. No mortality was seen within the 2 weeks of observation. The LD₅₀ was estimated to be greater than 2000 mg/kg.

3.5. Suppressive Activity of P. capitata

The aqueous and methanolic crude extracts of P. capitata significantly (p<0.05) reduced parasitaemia in the suppressive test (Table 3). The aqueous and methanolic extracts reduced parasitaemia and increased percentage suppression in a dose-dependent trend, with the highest suppressions of 88.12% and 89.62%, respectively. The methanolic extract exhibited superior suppression of parasite growth compared to the aqueous extract at the highest dose. The extracts at all tested doses prolonged the survival of the mice relative to the vehicle-treated groups (Table 3). The highest median survival time (MDST) for the aqueous and methanolic extracts was recorded as 30 and 28 days, respectively, at a dose of 400 mg/kg. The survival curve (Kaplan-Meier plot) of the crude extracts (Supplementary material) illustrates the survivability of the infected mice over 30 days. All the animals in the negative control group were censored by the 18th day. Approximately 40%, 20%, and 60% of the animals treated with 100, 200, and 400 mg/kg of the aqueous extract, respectively, survived at the end of the study. Conversely, 40% of the experimental animals treated with 100, 200, and 400 mg/kg of the methanol extract survived by the end of the study. Furthermore, all the animals in the positive control group survived at the end of the study.

Table 3.

Suppressive Activity of P. capitata

	AQUEOUS			METHANOLIC
Dose (mg/kg)	% PRST	% SUPP	MDST	% PRST	% SUPP	MDST
NC	68.97±1.93	NS	11.00	54.78±2.81	NS	11
50	36.22±3.86	34.70±7.20	14.00	31.84±8.35	43.52±6.23	18
100	26.83±3.64	61.10±5.27	18.00	25.60±6.30	53.28±6.77	18
200	19.68±0.50	71.46±0.73	28.00	19.68±1.12	64.07±9.13	24
400	8.20±2.26	88.12±3.27	30.00	5.69±2.92	89.62±4.25	28
PC (4)	2.52±0.40	96.35±0.58	30.00	1.57±0.53	97.14±5.28	30

% Parasitaemia represented as Mean ± SD, N = 5, NC = Negative Control group, PC = Artesunate, MDST = Median Survival Time, NA = undefined, NS = No Suppression. Values are significantly different at p < 0.005, compared to the negative control group.

3.6. Effect of P. capitata on Body Weight and Temperature in the Suppressive Test

Both the aqueous (Figure 2A) and methanolic (Figure 2B) extracts of P. capitata significantly prevented the weight loss associated with malaria infection in the suppressive test. At all tested doses, extract-treated groups exhibited positive percentage weight changes compared to the negative control group. Although the 50 mg/kg aqueous extract group did not show a weight gain, the percentage weight change was still significantly different (p < 0.05) from the negative control. Moreover, weight gain increased dose-dependently in both extract-treated groups. Malaria infection also induced hypothermia in the vehicle-treated group (Figure 3). This decline in body temperature was significantly (p < 0.05) reversed in all extract-treated groups. Both the aqueous and methanolic extracts demonstrated a dose-dependent effect in restoring body temperature toward normal levels.

Figure 2.

Percentage change in weight of mice infected with P. berghei on day 0 and day 4 in the 4-day suppressive assay treated with the aqueous (A) and methanol (B) extracts. N = 5, NC = Negative Control group, PC = Artesunate. Values are significantly different at p < 0.0001, ****compared to the negative control group

Figure 3.

Percentage change in temperature of mice infected with P. berghei on day 0 and day 4 in the 4-day suppressive assay treated with the aqueous (A) and methanol (B) extracts. N = 5, NC = Negative Control group, PC = Artesunate. Values are significantly different at ***p < 0.0005, ****p < 0.0001 compared to the negative control group

3.7. The Curative Activity of P. capitata

The aqueous and methanol crude extracts suppressed parasitaemia in the treated animals dose-dependently (Table 4), with the highest suppression of 89.86% and 79.24% respectively. The aqueous extract produced a superior suppression at all tested doses relative to the methanolic extract. Additionally, aqueous and methanolic extracts prolonged the survival of the treated animals relative to the negative control group, with the highest median survival times of 24.0 and 22.0, respectively. At the higher doses tested (200 and 400 mg/kg), the aqueous extract produced a superior median survival time, whereas the methanolic extract recorded a superior survival time at the lower doses (50 and 100 mg/kg). In the curative study, 100% of animals treated with artesunate and 20% of those treated with the aqueous extract at 200 mg/kg survived until the end of the 28-day observation period (Supplementary material). In contrast, all animals in the negative control group were censored by day 11, followed by complete mortality in the 50 mg/kg and 100 mg/kg aqueous extract groups by days 14 and 18, respectively. The 400 mg/kg aqueous extract group exhibited prolonged survival, with all animals censored by day 28. Similarly, treatment with the methanolic extract resulted in 20% survival in the 200 mg/kg and 400 mg/kg groups at the end of the study. However, all animals treated with 50 mg/kg and 100 mg/kg methanolic extract were censored by day 28.

Table 4.

Curative Activity of P. capitata

AQUEOUS METHANOL
Dose (mg/kg)	% SUPP	MDST	% SUPP	MDST
NC	NS	11.0	NS	12.0
50	32.85±9.70	11.0	17.79±3.10	14.0
100	61.40±6.99	14.0	52.74±4.09	18.0
200	72.28±5.05	24.0	66.26±7.26	19.0
400	89.86±2.10	24.0	79.24±5.19	22.0
PC (4)	95.36±1.25	30.0	96.43±2.20	30.0

% Suppression represented as Mean ± SD, N = 5, NC = Negative Control group, PC = Artesunate, MDST = Median Survival Time, NS = No Suppression.

3.8. Effect of the Extracts on Bodyweight and Temperature in the Curative Study

The aqueous (Figure 4A) and methanolic (Figure 4B) extracts of P. capitata significantly prevented the weight loss typically associated with malaria infection. Mice treated with either extract showed increased body weights at all tested doses, except in the 50 mg/kg groups. Nonetheless, all extract-treated groups demonstrated significantly higher percentage weight changes compared to the vehicle-treated group (p < 0.05). For the aqueous extract, weight gain exhibited a dose-dependent trend, with the greatest increase observed at 400 mg/kg. In contrast, weight gain in the methanol-treated groups did not follow a dose-dependent pattern, with the highest percentage increase recorded at 200 mg/kg.

Figure 4.

Percentage change in weight of mice infected with P. berghei on day 0 and day 4 in the suppressive assay and on day 3 and 7 in the curative test. Values are significantly different at ^*p < 0.05, ^**p < 0.005 compared to the negative control group

Malaria-induced hypothermia was evident in the vehicle-treated group (Figure 5). Both extracts significantly (p < 0.05) reversed this drop in body temperature of treated mice. The aqueous extract produced a dose-dependent restoration of body temperature, with the highest effect observed at 400 mg/kg. For the methanolic extract, temperature recovery was significant at all doses except 50 mg/kg.

Figure 5.

Percentage change in temperature of mice infected with P. berghei on day 3 and day 7 in the 4-day curative test. N = 5, NC = Negative Control group, PC = Artesunate. Values are significantly different at ****p < 0.0001 compared to the negative control group

3.9. In vivo Curative Activity of Isolated Compounds

The tested compounds demonstrated a dose-dependent increase in percentage parasitaemia suppression with the highest suppression of 85.66 and 86.49 recorded for friedelin and β-Sitosterol, respectively (Table 5). Notwithstanding, there was no significant difference in the percentage suppression for the tested doses for both compounds.

Table 5.

In vivo Curative Activity of Compounds

Dose (mg/kg)	% SUPP (mean ± SD) of compounds
	Friedelin	β-Sitosterol	Artesunate
3	77.61 ± 2.95	68.15 ± 6.71
10	84.63 ± 4.44	75.82 ± 0.67	97.00 ± 1.57
30	85.66 ± 4.88	86.49 ± 5.52

Values represented as Mean±SD, N=5, NC = Negative Control group. % SUPP; Percentage parasitaemia suppression.

4. Discussion

This work set out to validate the antimalarial claims of the stem extracts of P. capitata and explore the potential for discovering antimalarial compounds. Recent studies have highlighted the increasing integration of in vitro and in silico approaches in the identification of promising antimalarial agents from medicinal plants. However, in vitro and in vivo evaluations remain indispensable for confirming biological activity as well as therapeutic relevance. Accordingly, the findings of the present study provide important experimental validation of the antimalarial potential of P. capitata and its isolated compounds.²⁹

The aqueous and methanolic extracts exhibited promising antiplasmodial activity against the 3D7 and Dd2 strains of P. falciparum (Table 2). The methanolic extract was more active against both strains, suggesting that an ethanol extract, a similarly polar and traditionally used solvent, could likely serve as an effective alternative for extract preparation in ethnomedicinal applications of the plant. According to the classification by Philippe et al,³⁰ the crude extracts can be said to be highly active against the sensitive and resistant strains of P. falciparum. These findings are supported by earlier reports of the promising activity of the methanol leaf extract of the plant against the chloroquine-sensitive (NF54) strain.¹² This positions the whole plant as a potent antimalarial, requiring further clinical investigations.

The crude stem extracts of P. capitata demonstrated promising antimalarial activity in both suppressive and curative assays. The crude extracts in the suppressive assay inhibited parasite growth in a dose-dependent trend, with the methanolic extract demonstrating superior efficacy. Conversely, in the curative assay, mice treated with the aqueous extract demonstrated superior parasite suppression at all tested doses. The latter highlights the potential of the aqueous extract in managing established infections and supports its traditional use in the treatment of the disease. Weight loss observed with malaria is often linked to loss of appetite, disrupted metabolism, and hypoglycaemia.³¹ In both assays, the crude extracts significantly (p < 0.05) prevented the weight loss associated with the infection. Additionally, Plasmodium berghei-infected mice commonly exhibit impaired thermoregulation and progressive hypothermia.³² The crude extracts effectively alleviated malaria-induced hypothermia. The prolonged survival observed in extract-treated mice relative to the vehicle-treated groups can be attributed to the extract’s ability to reduce the degenerative consequences of the infection, further supporting the therapeutic potential of P. capitata stem extracts in treating the disease. The growing popularity of medicinal plants and herbal products has raised significant safety concerns.³³ The LD₅₀ of the aqueous and alcoholic extracts were estimated to be over 2000 mg/kg, suggesting a good safety margin. The extract, in addition, is non-toxic to red blood cells in the cytotoxicity assay, and was selective for the parasite (selectivity indexes (SIs) ≥90.0). These findings are consistent with reports by Ohikhena et al³⁴ where different solvent extracts of P. capitata were found to be safe in a brine shrimp lethality assay. These findings potentially guarantee the safety of the aqueous and alcoholic stem extracts of P. capitata.

Two triterpenoids (friedelin and friedelinol), a phytosterol (β-Sitosterol) and a glycoside (daucosterol) were isolated from the most active ethyl acetate fraction. Friedelinol, a reduced derivative of friedelin, was identified as a mixture with the latter, as seen in previous reports.^35,36 The isolated compounds generally demonstrated promising in vitro antiplasmodial activity against both tested strains (Table 2). The promising in vitro antiplasmodial activity of friedelin (3D7; 5.13±1.52 µM) is consistent with earlier reports against the 3D7 strain of P. falciparum.³⁷ However, the in vitro activity of the friedelin/friedelinol mixture was approximately 20 times less potent than that of friedelin alone. This suggests friedelinol probably antagonises the antiplasmodial activity of friedelin. This is supported by a previous report by Noungoue et al,³⁸ which found that friedelinol exhibited no antiplasmodial activity against the P. falciparum W2 strain. In the in vivo studies, friedelin demonstrated significant curative antimalarial activity with the highest percentage suppression of 85.63%. The promising in vivo curative antimalarial activity of friedelin seen in this study reinforces its in vitro potency. Similar findings on the in vivo efficacy by Baah et al,¹⁷ support its potential as an antimalarial agent.

Sitosterol and its glucoside daucosterol demonstrated good in vitro antiplasmodial activity against the tested strains (Table 2). The in vitro activity of sitosterol against the 3D7 strain is consistent with previous studies (IC₅₀ of 17.76±2.86 µg/ml).³⁹ Daucosterol demonstrated the best activity among the isolates in vitro with an IC₅₀ of 0.84±0.002 against the 3D7 strain. This affirms its potential as a lead compound for the development of new antimalarial agents.⁴⁰ Daucosterol demonstrated superior activity against both strains in vitro relative to its aglycone, β-Sitosterol. Glycosylation has been shown to influence the efficacy of antimicrobial compounds, including those targeting Plasmodium parasites, as supported by studies from Dewey et al⁴¹ and Ivorra et al⁴² where daucosterol showed superior activity to sitosterol. This is attributed to glycosylation, enhancing the selective uptake of the compound by parasitised red blood cells or facilitating its interaction with parasite-specific transporters or enzymes, resulting in a more effective accumulation of the drug at the target site.⁴³ It should however, be noted that the in vitro activity of the crude methanol extract was generally superior to that of the isolated compounds, suggesting a synergistic action among the phytoconstituents in the crude extract to exert their antimalarial activity. Sitosterol significantly reduced parasitaemia in the in vivo assay (Table 5). The mechanism of action of its antimalarial activity can be ascribed to the inhibition of dihydrofolate reductase, as reported in a molecular docking study by Luxy & Sumathi.⁴⁴ The absence of significant differences in the in vivo antimalarial activity across the tested doses suggests that lower doses of the compounds may achieve comparable therapeutic effects while potentially minimising dose-related toxicities.

Parasitic plants exhibit significant phytochemical variation influenced by their host species. Studies on P. capitata have demonstrated that its phytochemical composition and consequently, biological activity, vary depending on the host plant.⁴⁵ This supports the hypothesis that host plants play a critical role in the chemical makeup and the subsequent therapeutic potential of parasitic plants. Consequently, the host species should be carefully considered when using parasitic plants for medicinal or research purposes.

Despite the promising findings, this study presents some limitations. The in vivo antimalarial activity was evaluated using a Plasmodium berghei murine model, which, although widely used, does not fully replicate human malaria caused by Plasmodium falciparum.⁴⁶ Additionally, while several bioactive compounds were successfully isolated, not all constituents of the extract could be evaluated due to limited quantities. This may have restricted a comprehensive assessment of their individual contributions to the observed activity. The study also did not investigate the detailed mechanisms of action as well as long-term toxicity and pharmacokinetic studies of the extracts and isolated compounds. Future research should therefore focus on mechanistic studies, expanded toxicity profiling and clinical validation to fully establish the therapeutic potential of Phragmanthera capitata.

5. Conclusion

The antimalarial potential of the stem of Phragmanthera capitata has been established in this study. The decline in parasitaemia coupled with the significant weight recovery and survival rate in the treated animals justifies the folkloric use of the plant in the treatment of malaria. Additionally, this work reports, for the first time, the isolation of friedelin, friedelinol, β-sitosterol, and daucosterol from the stem of P. capitata, establishing the plant as a potent source of antimalarial compounds. Further clinical studies are required to confirm the efficacy and safety of the isolated compounds.

Supplemental Material

Supplemental Material - Antimalarial Potential of Phragmanthera capitata: An Insight Into the Activity of Its Extracts and Isolated Compounds

Supplemental Material for Antimalarial Potential of Phragmanthera capitata: An Insight Into the Activity of Its Extracts and Isolated Compounds by Reinhard Isaac Nketia, Nkrumah Desmond, Silas Adjei, Arnold Forkuo Donkor, Daniel Anokwah, Evelyn Asante-Kwatia, Isaac Kingsley Amponsah, Edmund Ekuadzi and Gustav Komlaga in Natural Product Communications

Footnotes

ORCID iDs

Reinhard Isaac Nketia

Desmond Nkrumah

Silas Adjei

Isaac Kingsley Amponsah

Edmund Ekuadzi

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Supplemental Material

Supplemental Material for this article is available online.

Appendix

References

Oteng Mintah

Asafo-Agyei

Archer

, et al. Medicinal Plants for Treatment of Prevalent Diseases. Pharmacogn - Med Plants. 2019. doi:10.5772/INTECHOPEN.82049.

Garg

Faheem

Singh

. Role of Medicinal Plant in Human Health Disease. Asian J Plant Sci Res. 2021. doi:10.36648/2249-7412.11.1.19-21.

Baah

Acheampong

Amponsah

, et al. Hydroethanol extract and triterpenoids of Senegalia ataxacantha show antiplasmodial activity and the compounds are predicted to inhibit parasite lactate dehydrogenase (pfLDH) as indicated by molecular docking studies. Sci African. 2024;26:e02455. doi:10.1016/J.SCIAF.2024.E02455.

Nketia

Desmond

Forkuo

, et al. Antimalarial activity of the aqueous extract and anthraquinones from the root of Senna siamea (LAM) H.S. Irwin & Barneby (Fabaceae). Sci African. 2025;27(5):e02579. doi:10.1016/j.sciaf.2025.e02579.

Alves

MBN

De Barros

Lugtenburg

CAB

Barros

. Uso empírico de plantas medicinais no tratamento de doenças/Empirical use of medicinal plants in the treatment of diseases. Brazilian J Dev. 2022;8(4):31491-31503. doi:10.34117/BJDV8N4-569.

Takem

Lawal

BAS

Udia

Udoh

. Assessment of glycaemic property of Phragmanthera capitata. Int J Pharm Pharm Res. 2015;4(4):1-8. https://www.ijppr.humanjournals.com.

Komlaga

Agyare

Dickson

, et al. Medicinal plants and finished marketed herbal products used in the treatment of malaria in the Ashanti region, Ghana. J Ethnopharmacol. 2015;172:333-346. doi:10.1016/j.jep.2015.06.041.

Etame-Loe

Okalla Ebongue

Ngaba

, et al. Évaluation des activités antioxydante et anti-inflammatoire de l’extrait aqueux de l’haustorium de Phragmanthera capitata (Sprengel) S. Balle (Loranthaceae). CC NgouleJournal Anim Plant Sci. 2018;36:5933-5941. https://m.elewa.org/Journals/wp-content/uploads/2018/06/3.Etame-Loe.pdf.

Takem

Lawal

BAS

Udia

Udoh

. Potentiating effect of Phragmanthera capitata extract in haematopoietic activities in Wistar rats. Int J Pharmacol Pharm Sci. 2015;2(1):1-6.

10.

Ohikhena

Wintola

Afolayan

. Evaluation of the Antibacterial and Antifungal Properties of Phragmanthera capitata (Sprengel) Balle (Loranthaceae), a Mistletoe Growing on Rubber Tree, Using the Dilution Techniques. Sci World J. 2017;2017:9658598. doi:10.1155/2017/9658598.

11.

Feudjio

Njateng

GSS

Kuiate

. Evaluation of Antidiabetic Activity of Aqueous Extract of Leaves from Phragmanthera capitata (Sprengel) S. Balle (Laurenthaceae) in Wistar Albino Rats. J Dis Med Plants. 2018;4(4):96-109. doi:10.11648/J.JDMP.20180404.11.

12.

Lenta

Ateba

Chouna

, et al. Two 2,6-Dioxabicyclo[3.3.1]nonan-3-ones from Phragmanthera capitata (Spreng.) Balle (Loranthaceae). Helv Chim Acta. 2015;98(7):945-952. doi:10.1002/HLCA.201400367.

13.

Mfotie

Maza

HLD

Swain

, et al. Natural Compounds Isolated from African Mistletoes (Loranthaceae) Exert Anti-Inflammatory and Acetylcholinesterase Inhibitory Potentials: In vitro and In silico Studies. Appl Sci. 2023;13(4):2606. doi:10.3390/APP13042606.

14.

George

Mbong

, et al. Ethno-botanical Verification and Phytochemical Profile of Ethanolic leaves Extract of Two Medicinal Plants (Phragmenthera capitata and Lantana camara) used in Nigeria using GC- MS Technique. Acta Biol Forum. 2023;2(3):1-7. doi:10.51470/abf.2023.2.3.1.

15.

WHO . World Malaria Report. 2024. https://www.wipo.int/amc/en/mediation/%0Ahttps://www.who.int/teams/global-malaria-programme/reports/world-malaria-report-2023.

16.

Komlaga

Forkuo

Suleman

Nkrumah

Nketia

Bekoe

. Antimalarial Property and Acute Toxicity of the Leaves of Theobroma cacao L. Evidence-based Complement Altern Med. 2021;2021:2021. doi:10.1155/2021/2852442.

17.

Baah

Mensah

Asante-Kwatia

, et al. In vivo Antiplasmodial Activity of Different Solvent Extracts of Myrianthus libericus Stem Bark and Its Constituents in Plasmodium berghei -Infected Mice. Evidence-based Complement Altern Med. 2020;2020:8703197. doi:10.1155/2020/8703197.

18.

Evans

. Trease and Evans’ Pharmacognosy: Sixteenth Edition. W.B. Saunders; 2009.

19.

Smilkstein

Sriwilaijaroen

Kelly

Wilairat

Riscoe

. Simple and Inexpensive Fluorescence-Based Technique for High-Throughput Antimalarial Drug Screening. Antimicrob Agents Chemother. 2004;48(5):1803-1806. doi:10.1128/AAC.48.5.1803-1806.2004.

20.

Kwansa-Bentum

Agyeman

Larbi-Akor

Anyigba

Appiah-Opong

. In vitro Assessment of Antiplasmodial Activity and Cytotoxicity of Polyalthia longifolia Leaf Extracts on Plasmodium falciparum Strain NF54. Malar Res Treat. 2019;2019:6976298. doi:10.1155/2019/6976298. Published online.

21.

Obakiro

Kiprop

K’Owino

, et al. Phytochemical, Cytotoxicity, and Antimycobacterial Activity Evaluation of Extracts and Compounds from the Stem Bark of Albizia coriaria Welw ex. Oliver. Evidence-based Complement Altern Med. 2022;2022(1):7148511. doi:10.1155/2022/7148511.

22.

Touitou

Portaluppi

Smolensky

Rensing

. Ethical Principles and Standards for the Conduct of Human and Animal Biological Rhythm Research. Chronobiol Int. 2004;21(1):161-170. doi:10.1081/CBI-120030045.

23.

Percie du Sert

Hurst

Ahluwalia

, et al. The ARRIVE guidelines 2.0: Updated guidelines for reporting animal research. Br J Pharmacol. 2020;177(16):3617-3624. doi:10.1111/BPH.15193.

24.

OECD . Test No. 425: Acute Oral Toxicity: Up-and-Down Procedure; 2020.

25.

AVMA . American Veterinary Medical Association Guidelines for the Euthanasia of Animals; 2020.

26.

Peters

Portus

Robinson

. The chemotherapy of rodent malaria, XXII: The value of drug-resistant strains of P. berghei in screening for blood schizontocidal activity. Ann Trop Med Parasitol. 1975;69(2):155-171. doi:10.1080/00034983.1975.11686997.

27.

Nkrumah

Nketia

Turkson

, et al. Malaria: Epidemiology, Life Cycle of Parasite, Control Strategies and Potential Drug Screening Techniques. In: Mosquito-Borne Tropical Diseases. doi:10.5772/INTECHOPEN.1007804. IntechOpen; 2024.

28.

Ansong

Nkrumah

Nketia

, et al. Antimalarial Properties of Sida cordifolia L. Leaf Extract in Mice: Survivability Depends Less on Parasitaemia Suppression. Evidence-Based Complement Altern Med. 2023;2023(1):1-8. doi:10.1155/2023/5560711.

29.

Gogoi

Rudrapal

Celik

Kaishap

Chetia

. In vitro and in silico guided identification of antimalarial phytoconstituent(s) in the root of Citrus maxima (Burm.) Merr. J Biomol Struct Dyn. 2025;43(2):599-610. doi:10.1080/07391102.2023.2283154.

30.

Philippe

Angenot

De Mol

, et al. In vitro screening of some Strychnos species for antiplasmodial activity. J Ethnopharmacol. 2005;97:535-539. doi:10.1016/j.jep.2004.12.011. Published online.

31.

Ogetii

Akech

Jemutai

, et al. Hypoglycaemia in severe malaria, clinical associations and relationship to quinine dosage. BMC Infect Dis. 2010;10(1):1-9. doi:10.1186/1471-2334-10-334/TABLES/3.

32.

Lopes

Folha Santos

Marques

OLC

, et al. An analysis of the influence of sex hormones on Balb/c mice infected with Plasmodium berghei. Microb Pathog. 2016;90:7-12. doi:10.1016/J.MICPATH.2015.10.020.

33.

Ekor

. The growing use of herbal medicines: Issues relating to adverse reactions and challenges in monitoring safety. Front Neurol. doi:10.3389/FPHAR.2013.00177/PDF.

34.

Ohikhena

Wintola

Afolayan

. Toxicity assessment of different solvent extracts of the medicinal plant, Phragmanthera capitata (sprengel) balle on brine shrimp (artemia salina). Int J Pharmacol. 2016;12(7):701-710. doi:10.3923/IJP.2016.701.710.

35.

Fun

Boonnak

Chantrapromma

. A cocrystal of friedelan-3β-ol and friedelin (0.75/0.25). Acta Crystallogr Sect E-structure Reports Online. 2007;63(4):o2014-o2016. doi:10.1107/S1600536807013979.

36.

Radi

El-Shiekh

El-Halawany

Abdel-Sattar

. Friedelin and 3β-Friedelinol: Pharmacological Activities. Rev Bras Farmacogn.Springer. 2023;33(5):886-900. doi:10.1007/s43450-023-00415-5.

37.

Mishra

Kumar

Darokar

Shanker

. Novel bioactive compound from the bark of Putranjiva roxburghii Wall. Nat Prod Res. 2019;35(10):1738-1740. doi:10.1080/14786419.2019.1633650.

38.

Noungoue

Chaabi

Ngouela

, et al. Antimalarial compounds from the stem bark of Vismia laurentii. Zeitschrift fur Naturforsch - Sect C J Biosci. 2009;64(3-4):210-214. doi:10.1515/ZNC-2009-3-410.

39.

Mahfur

Wahyuono

Purwantini

Setyowati

. Antiplasmodial Activity, Isolation and Structure Elucidation of Steroid Compound from Sponge Hyrtios reticulatus. Indones J Pharm. Published online October 29 2024.

40.

Batista

De Jesus Silva Júnior

De Oliveira

. Plant-Derived Antimalarial Agents: New Leads and Efficient Phytomedicines. Part II. Non-Alkaloidal Natural Products. Mol. 2009;14(8):3037-3072. doi:10.3390/MOLECULES14083037.

41.

Dewey

Kidder

. Biological activity of sterol glycosides. Biochem Pharmacol. 1962;11(1):53-56. doi:10.1016/0006-2952(62)90090-4.

42.

Ivorra

D’ocon

Payá

Villar

. Antihyperglycemic and insulin-releasing effects of beta-sitosterol 3-beta-D-glucoside and its aglycone, beta-sitosterol. Arch Int Pharmacodyn Ther. 1988. Published online.

43.

Heikham

Gupta

Kumar

, et al. Preferential targeting of human erythrocytes infected with the malaria parasite Plasmodium falciparum via hexose transporter surface proteins. Int J Pharm. 2015;483(1-2):57-62. doi:10.1016/J.IJPHARM.2015.02.011.

44.

Luxy

Sumathi

. Unlocking potential: Beta-sitosterol from Cyperus rotundus as a promising antimalarial agent revealed through molecular docking analysis. Int J Mosq Res. 2023;10(6):58-62. doi:10.22271/23487941.2023.v10.i6a.718.

45.

Isikhuemen

Olisaemeka

Oyibotie

. Host specificity and phytochemical constituents of mistletoe and twigs of parasitized plants: Implications for blanket application of mistletoe as cure-all medicine. J Med Herbs Ethnomedicine. 2020:30-37. doi:10.25081/JMHE.2020.V6.5686. Published online March 15.

46.

Adebayo

Ayanda

Rottmann

, et al. The Importance of Murine Models in Determining In vivo Pharmacokinetics, Safety, and Efficacy in Antimalarial Drug Discovery. Pharm. 2025;18(3):424. doi:10.3390/PH18030424.

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