Sage Journals: Discover world-class research

Abstract

Mosquito-borne diseases are a consistent problem in Vietnam. Additionally, freshwater snail species are agricultural pests and are known to be intermediate hosts for several parasitic worms. There is a need for new and complementary botanical pesticidal agents for controlling these pests and essential oils have shown promise. In this work, essential oils from 2 species of Callicarpa (C. rubella and C. sinuata) and 4 species of Premna (P. chevalieri, P. corymbosa, P. maclurei, and P. tomentosa) were screened for mosquito larvicidal activity against Aedes albopictus and Culex quinquefasciatus and for molluscicidal activity against 3 freshwater snail species, Gyraulus convexiusculus, Pomacea canaliculata, and Tarebia granifera. Callicarpa rubella essential oil showed exceptional larvicidal activity against Cx. quinquefasciatus with 24-h LC₅₀ of 9.8 μg/mL. In addition to C. rubella, the essential oils of P. chevalieri and P. tomentosa showed notable molluscicidal activities against P. canaliculata with LC₉₀ values ≤ 20 μg/mL. These Callicarpa and Premna essential oils were all rich in sesquiterpenes and should be considered for continued investigation as botanical pesticidal agents.

Keywords

molluscicidal larvicidal lamiaceae sesquiterpenes essential oils

Introduction

Synthetic pesticides have played an important role in controlling mosquitos and snails for decades. However, synthetic pesticides are harmful to the environment and human health, the most serious is the development of pesticide resistant target organism populations.^1‐4 In recent years, essential oils have emerged as a biodegradable, nontoxic, and environmentally friendly source of pesticides.^5,6 Essential oils are rich and complex in chemical composition, which make it difficult for target organisms to become resistant to the essential oils.^6,7

Some freshwater snail species are important as intermediate hosts that cause diseases in humans or animals. Pomacea canaliculata (Lamarck) is native to South America.⁸ In many Southeast Asian countries, P. canaliculata is of particular interest as a troublesome invasive species and considered one of the most harmful pests to rice. Moreover, P. canaliculata is an intermediate host for human parasites such as Angiostrongylus cantonensis, which leads to eosinophilic meningitis,⁹ Gnathostoma spinigerum, which is the cause of gnathostomiasis,¹⁰ and Angiostrongylus vasorum which leads to eosinophilic encephalitis,¹¹ and the intestinal fluke Echinostoma ilocanum.¹²

Gyraulus convexiusculus (Hutton) is an intermediate host for several trematode parasites^13,14 including Echinostoma revolutum, Australapatemon burti,¹⁵ Artyfechinostomum malayanum (intestinal flukes),¹⁶ Sanguinicola armata (blood fluke),¹⁷ and Cercaria sp.¹⁸ In addition, G convexiusculus is an intermediate host of Olveria indica, an amphistome parasite.¹⁹

Tarebia granifera (Lamarck) is a host of several parasitic trematodes including Paragonimus westermani (the oriental lung fluke) as well as the intestinal flukes Haplorchis taichui,²⁰ Centrocestus formosanus, and Haplorchis pumilio.²¹ This species is also considered to be an intermediate host of Philophthalmus gralli, which is the cause of oriental eye-fluke in birds.²²

The Asian tiger mosquito, Aedes albopictus (Skuse) is distributed throughout the world. This species acts as a vector of viruses such as the dengue viruses, chikungunya virus, ²³ and Zika virus.²⁴ The mosquito Culex quinquefasciatus (Say) is one of mosquito vectors transmitting lymphatic filariasis, including Saint Louis encephalitis virus,²⁵ West Nile virus,²⁶ and Zika virus.²⁷ Lymphatic filariasis affects over 120 million people in 81 countries throughout the tropics and sub-tropics of Asia, Africa, the western Pacific, and parts of the Caribbean and South America; and an estimated 1.34 billion live in areas where filariasis is endemic and are at risk of infection.²⁸

The essential oil compositions and larvicidal activities against Aedes aegypti have been reported for Callicarpa rubella, C. sinuata,²⁹ Premna chevalieri, P. corymbosa, P. maclurei, and P. tomentosa.³⁰ In this present work, we have extended the pesticidal bioassays to include mosquito larvicidal activities against Aedes albopictus and Culex quinquefasciatus as well as molluscicidal activities against 3 freshwater snail species, Gyraulus convexiusculus, Pomacea canaliculata, and Tarebia granifera. In addition, we have screened these essential oils for insecticidal activity against the non-target water bug, Diplonychus rusticus.

Results and Discussion

Essential Oil Compositions

The major components of the essential oils for the Callicarpa and Premna species, previously published, are summarized in Table 1.

Table 1.

Major Components of the Leaf Essential Oils of Callicarpa and Premna Species From Vietnam^a.

Plant essential oil	Major components	Ref
Callicarpa nudiflora	β-Pinene (34.2%), caryophyllene oxide (20.1%), α-pinene (8.1%), myrtenal (6.8%)	²⁹
Callicarpa petelotii	α-Humulene (53.8%), α-selinene (12.8%), humulene epoxide II (8.1%)	²⁹
Callicarpa rubella	(E)-Caryophyllene (18.0%), α-cubebene (17.4%), δ-cadinene (4.6%), bicyclogermacrene (4.6%), α-copaene (4.6%)	²⁹
Callicarpa sinuata	α-Humulene (24.8%), α-copaene (12.6%), humulene epoxide II (6.7%), spathulenol (5.9%)	²⁹
Premna cambodiana	α-Copaene (23.3%), (E)-caryophyllene (12.8%), α-gurjunene (11.3%), δ-cadinene (5.5%)	³⁰
Premna chevalieri	(E)-Caryophyllene (31.5%), β-pinene (16.8%), α-pinene (12.2%), α-humulene (7.5%), caryophyllene oxide (5.3%)	³⁰
Premna corymbosa	allo-Aromadendrene (39.7%), (E)-caryophyllene (13.3%), α-copaene (8.1%)	³⁰
Premna maclurei	(E)-Caryophyllene (30.7%), caryophyllene oxide (12.3%), δ-cadinene (8.4%), spathulenol (6.8%), α-humulene (5.3%)	³⁰
Premna mekongensis (Chu Mom Ray)	Bicyclogermacrene (11.9%), (E)-nerolidol (7.5%), germacrene D (5.6%), viridiflorol (5.6%)	³⁰
Premna mekongensis (Ngoc Linh)	α-Pinene (66.9%), (E)-caryophyllene (14.7%)	³⁰
Premna tomentosa	(E)-Caryophyllene (22.0%), germacrene D (11.4%), ledol (6.1%), α-selinene (5.5%), α-gurjunene (5.2%), trans-β-elemene (5.0%)	³⁰

Photographs and botanical descriptions of the plants described in this study are shown in Supplemental Table S1.

Mosquito Larvicidal Activity

The C. rubella, C. sinuata, P. chevalieri, P. corymbosa, P. maclurei, and P. tomentosa leaf essential oils were screened for mosquito larvicidal activity against Aedes albopictus and Culex quinquefasciatus (Table 2). In addition, the essential oils were tested for insecticidal activity on the non-target water bug, Diplonychus rusticus (Figure 1).

Figure 1.

Chemical structures of the main compounds of essential oils Callicarpa and Premna species from Vietnam.

Table 2.

Mosquito Larvicidal Activities of Callicarpa and Premna Essential Oils^a.

Plant essential oil	LC₅₀ (fiducial limits)	LC₉₀ (fiducial limits)	χ²	P	SI ^b
	Aedes albopictus, 24-h
Callicarpa nudiflora	33.00 (30.49-35.80)	48.40 (44.64-53.38)	1.36	.715	---
Callicarpa petelotii	37.70 (34.48-41.16)	60.31 (53.89-70.42)	1.61	.807	---
Callicarpa rubella	50.48 (43.91-58.98)	157.9 (123.1-223.2)	7.57	.056	2.7
Callicarpa sinuata	41.26 (37.78-45.46)	64.66 (57.86-74.37)	0.909	.823	2.6
Premna chevalieri	46.61 (43.44-50.42)	64.19 (59.02-71.86)	0.679	.878	1.7
Premna cambodiana	75.38 (65.47-89.81)	202.1 (154.4-304.0)	8.34	.080	---
Premna corymbosa	45.88 (42.67-49.76)	64.26 (58.95-72.06)	1.99	.575	2.5
Premna maclurei	94.72 (86.13-105.17)	154.1 (138.8-175.4)	20.3	.000	---
Premna mekongensis (Chu Mom Ray)	37.70 (34.48-41.16)	60.31 (53.89-70.42)	1.61	.807	2.2
Premna mekongensis (Ngoc Linh)	25.67 (23.20-28.40)	51.11 (44.51-61.22)	2.94	.569	5.1
Premna tomentosa	39.23 (36.52-42.22)	54.97 (51.04-60.24)	0.958	.812	2.7
Permethrin control	0.0024 (0.0021-0.0026)	0.0042 (0.0038-0.0049)	4.64	.031	---
	Culex quinquefasciatus, 24-h
Callicarpa nudiflora	Not tested ^c
Callicarpa petelotii	Not tested ^c
Callicarpa rubella	9.842 (8.649-11.158)	26.61 (22.22-33.77)	15.9	.003	13.7
Callicarpa sinuata	46.67 (41.24-53.29)	123.5 (100.8-162.5)	2.02	.569	2.3
Premna cambodiana	41.64 (36.82-47.58)	110.0 (89.9-143.8)	42.8	.000	---
Premna chevalieri	75.89 (69.19-84.05)	123.7 (111.7-140.3)	11.3	.010	1.0
Premna corymbosa	37.07 (33.88-40.83)	59.61 (54.05-67.37)	8.89	.031	3.1
Premna maclurei	67.53 (58.83-79.63)	184.2 (142.7-267.0)	0.245	.970	2.0
Premna mekongensis (Chu Mom Ray)	26.67 (27.02-32.56)	53.39 (47.16-62.96)	3.23	.520	3.1
Premna mekongensis (Ngoc Linh)	43.10 (39.60-47.19)	65.73 (59.94-73.77)	9.02	.061	3.0
Premna tomentosa	52.03 (47.81-57.33)	79.05 (70.99-90.26)	9.47	.024	2.1
Permethrin control	0.0165 (0.0149-0.0181)	0.0305 (0.0266-0.0367)	5.24	.073	---
	Diplonychus rusticus, 24-h
Callicarpa nudiflora	Not tested ^c				---
Callicarpa petelotii	Not tested ^c				---
Callicarpa rubella	134.4 (124.8-145.0)	214.7 (198.0-237.0)	38.1	.000	---
Callicarpa sinuata	105.5 (96.3-116.6)	164.7 (149.2-185.8)	12.6	.006	---
Premna cambodiana	Not tested ^c				---
Premna chevalieri	79.12 (76.60-81.94)	91.40 (87.66-97.26)	10.6	.014	---
Premna corymbosa	116.1 (106.4-127.7)	176.2 (160.4-197.4)	19.5	.000	---
Premna maclurei	Not tested ^c				---
Premna mekongensis (Chu Mom Ray)	82.90 (80.54-85.77)	92.68 (89.23-97.94)	0.00064	.98	---
Premna mekongensis (Ngoc Linh)	130.0 (124.7-135.4)	158.0 (151.1-167.1)	0.797	.85	---
Premna tomentosa	107.2 (97.8-118.6)	169.6 (153.7-191.3)	23.4	.000	---
	Aedes albopictus, 48-h
Callicarpa nudiflora	31.64 (29.14-34.47)	47.59 (43.72-52.74)	2.53	.469	---
Callicarpa petelotii	30.41 (27.78-33.36)	51.36 (45.33-61.13)	3.88	.422	---
Callicarpa rubella	45.14 (39.30-52.48)	143.7 (113.0-199.8)	8.18	.042	2.6
Callicarpa sinuata	37.10 (33.44-41.49)	64.23 (58.19-72.75)	1.91	.591	2.3
Premna cambodiana	62.94 (55.82-72.05)	149.5 (121.5-201.3)	3.27	.514	---
Premna chevalieri	45.65 (42.53-49.35)	63.24 (58.21-70.58)	0.407	.939	1.4
Premna corymbosa	35.57 (32.65-38.93)	55.47 (50.66-62.03)	3.81	.282	2.7
Premna maclurei	72.27 (65.22-80.65)	126.0 (112.9-144.7)	14.0	.003	---
Premna mekongensis (Chu Mom Ray)	35.04 (32.06-38.32)	56.43 (50.27-66.17)	4.92	.296	---
Premna mekongensis (Ngoc Linh)	23.79 (21.51-26.32)	47.23 (41.16-56.51)	2.54	.638	5.0
Premna tomentosa	36.21 (33.60-39.09)	51.84 (48.02-56.89)	0.859	.835	1.8
	Culex quinquefasciatus, 48-h
Callicarpa nudiflora	Not tested ^c				---
Callicarpa rubella	4.495 (3.995-5.003)	8.983 (7.760-11.073)	21.6	.000	25.7
Callicarpa petelotii	Not tested ^c				---
Callicarpa sinuata	35.48 (31.39-40.23)	95.27 (79.00-121.90)	10.7	.013	2.4
Premna cambodiana	20.78 (18.74-23.02)	42.37 (36.84-50.83)	4.13	.388	---
Premna chevalieri	56.63 (50.17-64.32)	113.3 (100.3-131.9)	27.9	.000	1.2
Premna corymbosa	30.95 (27.95-34.36)	54.13 (48.83-61.53)	15.8	.001	3.1
Premna maclurei	43.14 (36.81-51.60)	175.1 (129.3-268.5)	16.1	.001	---
Premna mekongensis (Chu Mom Ray)	23.75 (21.33-26.42)	51.48 (44.47-62.17)	2.95	.566	---
Premna mekongensis (Ngoc Linh)	32.77 (29.27-36.79)	77.55 (65.63-96.40)	12.18	.016	3.6
Premna tomentosa	46.20 (41.76-51.55)	76.50 (69.33-86.79)	16.7	.001	1.4
	Diplonychus rusticus, 48-h
Callicarpa nudiflora	Not tested ^c				---
Callicarpa petelotii	Not tested ^c				---
Callicarpa rubella	115.6 (106.1-125.8)	200.0 (183.7-221.9)	21.9	.000	---
Callicarpa sinuata	84.28 (76.60-93.67)	137.3 (123.5-156.8)	10.4	.016	---
Premna cambodiana	Not tested ^c				---
Premna chevalieri	65.80 (63.15-68.29)	77.16 (74.28-80.99)	0.00466	1.000	---
Premna corymbosa	96.77 (87.65-107.75)	162.9 (146.6-185.3)	17.8	.001	---
Premna maclurei	Not tested ^c				---
Premna mekongensis (Chu Mom Ray)	Not tested ^c				---
Premna mekongensis (Ngoc Linh)	117.8 (112.1-123.8)	154.8 (145.1-168.9)	6.60	.086	---
Premna tomentosa	66.46 (60.71-73.07)	107.1 (97.5-120.3)	7.94	.047	---

Data are presented as LC₅₀ and LC₉₀ values with 95% confidence limits (log-probit analysis) obtained from 6 independent experiments carried out in quadruplicate, after 24-h and 48-h of treatment.

SI = selectivity index = LC₅₀ (non-target species)/LC₅₀ (mosquito larvae).

Not tested due to insufficient essential oil.

Dias and Moraes ³¹ have suggested that essential oils with 24-h LC₅₀ less than 100 μg/mL should be considered to be “active” while LC₅₀ above 100 μg/mL should be “inactive.” Using this criterion, all of the Callicarpa and Premna essential oils could be considered to be active. Based on our experience,^29,30,32,33 however, we suggest amending the definition of active larvicidal essential oils. Essential oils with 24-h LC₅₀ <10 μg/mL should be considered “exceptionally active,” those with 24-h LC₅₀ between 10 μg/mL and 50 μg/mL “very active,” those with 24-h LC₅₀ between 50 μg/mL and 100 μg/mL “moderately active, and LC₅₀ > 100 μg/mL are “inactive.” In this case, C. rubella leaf essential oil is exceptionally active against Cx. quinquefasciatus, but only marginally active on Ae. albopictus larvae. In a previous study, C. rubella essential oil showed a 24-h LC₅₀ of 26.0 μg/mL (ie, very active) against Ae. aegypti .²⁹

In addition to the breakdown based on lethality of the essential oils against the target organisms, we can propose a “selectivity index” (SI, see Table 2) based on the lethality of each essential oil against target organisms compared to its lethality against non-targets (in this case, D. rusticus). That is, not only are larvicidal activities important, but also selectivity for the target species is also important. In this study, C. rubella essential oil showed the best overall selective lethality on Cx. quinquefasciatus compared to D. rusticus. Of course, the selectivity index will depend on the non-target organism(s) chosen and it remains to be determined what constitutes a “good SI.”

Most of the Callicarpa and Premna essential oils in this study were dominated by sesquiterpenes. It is tempting to suggest that sesquiterpenes are responsible for the larvicidal activities observed. The major sesquiterpene components in C. rubella essential oil were (E)-caryophyllene (18.0%) and α-cubebene (17.4%). The high concentration of (E)-caryophyllene in C. rubella oil cannot account for the exceptional larvicidal activity of that essential oil on Cx. quinquefasciatus, however. The sesquiterpenes (E)-caryophyllene, α-humulene, and caryophyllene oxide showed only weak activity against Cx. quinquefasciatus with 24-h LC₅₀ values of 161, 108, and 99 μg/mL, respectively (see Supplemental Table S2).³⁴ Nevertheless, (E)-caryophyllene was present in most essential oils with strong larvicidal activity.⁷ Essential oils characterized by (E)-caryophyllene and caryophyllene oxide exhibited larvicidal activity against Ae. aegypti.^35,36 Piper purusanum essential oil is characterized by (E)-caryophyllene, α-humulene, and germacrene D, and has shown strong larvicidal activity against Ae. aegypti and Ae. albopictus.³⁷ The unripe fruit peel of Hymenaea courbaril essential oil was characterized by germacrene D (31.9%) and (E)-caryophyllene (27.1%) and exhibited strong larvicidal activity against Ae aegypti.³⁸ Sesquiterpene hydrocarbons and oxygenated sesquiterpenoids dominated the essential oil of Callicarpa candicans, which showed exceptional mosquito larvicidal activities against Ae. aegypti and Cx. quinquefasciatus (24-h LC₅₀ = 2.7 and 1.2 μg/mL, respectively).²⁹ Interestingly, Premna flavescens, with 92.2% sesquiterpene hydrocarbons, was relatively inactive against Ae. aegypti and Ae. albopictus larvae with 24-h LC₅₀ values of 64.7 and 90.0 μg/mL, respectively.³⁰ Apparently, synergistic and/or antagonistic effects of essential oil components play a role in the larvicidal activities.³⁹

Callicarpa nudiflora essential oil was dominated by β-pinene (34.2%) and the very good larvicidal activity of C. nudiflora against Ae. albopictus (24-h LC₅₀ = 33.00 μg/mL) can be attributed to the larvicidal activity of β-pinene against Ae. albopictus (24-h LC₅₀ = 8.51 μg/mL, see Supplemental Table S2). Likewise, P. mekongensis essential oil from Ngoc Linh, an α-pinene-rich chemotype (66.9% α-pinene) also showed good larvicidal activity against Ae. albopictus with 24-h LC₅₀ of 25.67 μg/mL and SI of 5.1. Essential oils are complex mixtures of many compounds, and synergistic effects between the essential oil components are likely responsible for the enhanced larvicidal activities compared to the individual components that were tested. Essential oils containing high levels of α-pinene showed strong larvicidal activity against Culex pipiens^40‐42 and Ae. albopictus.⁴³

Molluscicidal Activity

The Callicarpa and Premna leaf oils were screened for molluscicidal activity against the freshwater snails, Gyraulus convexiusculus, Pomacea canaliculata, and Tarebia granifera (Table 3).

Table 3.

Molluscicidal Activities of Callicarpa and Premna Essential Oils^a.

Plant essential oil	LC₅₀ (fiducial limits)	LC₉₀ (fiducial limits)	χ²	P	SI ^b
	Gyraulus convexiusculus
Callicarpa nudiflora	17.60 (15.88-19.49)	35.45 (30.89-42.37)	0.261	.992	---
Callicarpa petelotii	25.30 (23.25-27.54)	40.72 (36.40-47.47)	0.595	.964	---
Callicarpa rubella	20.10 (18.12-22.29)	40.92 (35.51-49.34)	5.61	.061	5.2
Callicarpa sinuata	14.69 (12.00-17.41)	39.23 (34.28-46.49)	16.8	.001	4.2
Premna cambodiana	41.85 (38.14-45.89)	71.49 (63.17-84.97)	6.59	.159	---
Premna chevalieri	11.54 (10.47-12.70)	21.62 (19.05-25.50)	7.01	.072	4.2
Premna corymbosa	20.73 (17.82-23.74)	44.38 (39.35-51.69)	2.05	.359	4.0
Premna maclurei	19.16 (17.16-21.41)	33.69 (30.14-38.92)	4.01	.261	---
Premna mekongensis (Chu Mom Ray)	9.190 (8.553-9.850)	12.10 (11.32-13.12)	0.322	.956	9.0
Premna mekongensis (Ngoc Linh)	8.456 (7.460-9.536)	21.84 (18.53-26.99)	11.64	.020	15.4
Premna tomentosa	27.89 (24.83-31.47)	54.39 (48.46-62.69)	16.9	.001	3.1
	Pomacea canaliculata
Callicarpa nudiflora	Not tested ^c				---
Callicarpa petelotii	Not tested ^c				---
Callicarpa rubella	16.33 (15.18-17.78)	21.14 (19.42-23.74)	0.371	.831	10.2
Callicarpa sinuata	34.86 (32.41-37.68)	44.31 (41.07-48.77)	9.39	.009	3.7
Premna cambodiana	15.89 (14.64-17.46)	21.59 (19.65-24.53)	23.1	.000	---
Premna chevalieri	6.018 (5.518-6.684)	8.803 (7.865-10.431)	0.169	.919	10.4
Premna corymbosa	28.67 (26.50-31.60)	39.00 (35.31-44.88)	1.59	.451	4.5
Premna maclurei	Not tested ^c				---
Premna mekongensis (Chu Mom Ray)	4.844 (4.222-5.473)	11.61 (9.88-14.43)	0.285	.963	17.1
Premna mekongensis (Ngoc Linh)	11.84 (10.64-13.16)	23.82 (20.63-28.89)	39.63	.000	11.0
Premna tomentosa	10.34 (9.68-10.95)	13.01 (12.33-13.90)	0.0217	.999	13.0
	Tarebia granifera
Callicarpa nudiflora	37.08 (33.52-41.10)	74.21 (64.31-89.66)	5.67	.225	---
Callicarpa petelotii	24.13 (21.55-27.02)	57.24 (48.87-70.10)	6.75	.150	---
Callicarpa rubella	47.54 (42.72-53.05)	87.06 (78.47-98.68)	13.1	.004	2.5
Callicarpa sinuata	26.72 (23.46-30.45)	79.80 (65.47-103.53)	23.1	.000	2.1
Premna cambodiana	Not tested ^c				---
Premna chevalieri	35.90 (32.54-39.89)	60.74 (54.65-69.34)	5.93	.115	1.5
Premna corymbosa	50.28 (45.92-55.45)	80.03 (72.66-90.06)	9.05	.029	2.2
Premna maclurei	57.68 (53.04-63.31)	84.18 (76.73-94.45)	8.55	.036	---
Premna mekongensis (Chu Mom Ray)	29.45 (26.05-33.43)	80.85 (67.09-102.89)	11.54	.021	2.8
Premna mekongensis (Ngoc Linh)	80.69 (73.51-87.96)	145.2 (130.3-166.8)	18.20	.006	1.6
Premna tomentosa	32.14 (28.99-35.79)	56.43 (50.73-64.44)	2.89	.409	3.0

Data are presented as LC₅₀ and LC₉₀ values with 95% confidence limits (log-probit analysis) obtained from 5 independent experiments carried out in quadruplicate, after 24-h of treatment with an additional 24-h recovery time.

SI = selectivity index = LC₅₀ (non-target species)/LC₅₀ (snails).

Not tested due to insufficient essential oil.

The World Health Organization (WHO) has defined “active” molluscicidal botanicals as those that have LC₉₀ ≤ 20 μg/mL.⁴⁴ Based on this criterion, P chevalieri essential oil was active against G. convexiusculus and P. canaliculata, while C. rubella and P. tomentosa essential oils were active against P. canaliculata. In addition to these lethality data, C. rubella, P. chevalieri, and P. tomentosa essential oils were relatively selective for P. canaliculata compared to the non-target water bug with selectivity indices > 10.

In contrast to larvicidal activities, (E)-caryophyllene, α-humulene, and caryophyllene oxide have shown molluscicidal LC₉₀ values around 20 μg/mL on P canaliculata (see Supplemental Table S3),³⁴ and likely contributed to the molluscicidal activities of C. rubella, P. chevalieri, and P. tomentosa essential oils against P. canaliculata. The sesquiterpenoid-rich P. mekongensis essential oil (from Chu Mom Ray) showed excellent molluscicidal activity against G. convexiusculus and P. canaliculata with LC₉₀ values of 12.10 and 11.61 μg/mL, respectively, and SI values of 9.0 and 17.1, respectively. The role of sesquiterpenoids in molluscicidal activity has also been observed in previous studies. The essential oil of Xylopia langsdorffiana, characterized by germacrene D (22.9%), trans-β-guaiene (22.6%), and (E)-caryophyllene (15.7%), exhibited strong molluscicidal activity against Biomphalaria glabrata with an LC₅₀ value of 5.6 µg/mL.⁴⁵ Schinus terebinthifolius essential oil, containing sabinene (14.9%), γ-elemene (13.2%), and β-elemene (6.6%), was active against Theba pisana with an LC₅₀ value of 8.36 µg/mL. Meanwhile, Vitex agnuscastus essential oil consisting of (E)-caryophyllene (15.2%), 1,8-cineole (13.0%), and bicyclogermacrene (7.3%) exhibited an LC₅₀ value of 20.72 µg/mL.⁴⁶ Other studies that support this trend include the essential oil from the stem bark of Ocotea bracteosa ⁴⁷ and the leaf essential oil of Eugenia uniflora.⁴⁸

Materials and Methods

Isolation of Essential Oils

The essential oils were extracted from the fresh leaves of the plants by hydrodistillation. The leaves were shredded and hydrodistilled using a Clevenger type apparatus (Witeg Labortechnik). The essential oils were dried over anhydrous Na₂SO₄ and stored in sealed glass vials at 4 °C until used for analysis and bioactivity assays.

Preparation of Test Solutions

For all experiments, a 1% stock solution of the essential oils was prepared by dissolving each essential oil using ethanol. Different volumes of stock solution were introduced into test beakers containing 150 mL of distilled water to obtain test solutions with the desired concentrations.

Mosquito Larvicidal Assays

Adult Aedes albopictus mosquitoes were maintained continuously under laboratory conditions such as relative humidity 75%, temperature 25 ± 2 °C, cycles 12-h light and 12-h dark. Aedes mosquito larvae were reared in plastic containers and were fed on Koi fish food, the water in the plastic containers was renewed daily with tap water overnight. The eggs and first and early second instar larvae of Culex quinquefasciatus were collected in wild environments such as tires and ditches. The larvae were fed on the ripe fruit of Ficus racemosa until reaching the third and early fourth instar.

The essential oils were screened for larvicidal activity against Ae. albopictus and Cx. quinquefasciatus as described previously³²: 4 replicates, 20 larvae third and early fourth instar each, with essential oil concentrations of 100, 50, 25, 12.5, 6, and 3 μg/mL, permethrin positive control, larvicidal effects assessed after 24 and 48 h, lethality data analyzed by log-probit⁴⁹ analysis to obtain LC₅₀, LC₉₀, and 95% confidence limits using Minitab® 19 (Minitab, LLC).

Insecticidal Assay

Adults of Diplonychus rusticus (water bug) were collected from the wild, maintained in glass tanks (60 cm long × 50 cm wide) with a water depth of 20 cm under the same conditions for other organisms. Eichhornia crassipes plants were introduced into the tanks to help the water bug maintain its behaviors.

The essential oils were screened for insecticidal activity against the non-target water bug, Diplonychus rusticus as previously described⁵⁰: Quadruplicate assays, 20 adult insects each, essential oil concentrations of 200, 150, 100, 75, 50, and 25 μg/mL, insect lethality assessed after 24 and 48 h, log-probit analysis.

Molluscicidal Assays

The Premna and Callicarpa essential oils were screened for molluscicidal activity against Gyraulus convexiusculus, Pomacea canaliculata, and Tarebia granifera as previously described³⁴: Quadruplicate assays, 20 snails each, essential oil concentrations of 100, 50, 25, 12.6, and 6 μg/mL, tea saponin positive control, 24-h treatment, followed by 24-h recovery in fresh water, lethality data analyzed by log-probit.

Conclusions

Based on the pesticidal activity data presented in this report, we conclude that C. rubella essential oil could be an effective mosquito control agent for Cx. quinquefasciatus with limited environmental impact. In addition, the essential oils C. rubella, P. chevalieri, P. mekongensis, and P. tomentosa should be considered for control of the agricultural pest P. canaliculata. Additional research is needed to determine appropriate formulations to extend the lifetimes of the essential oils in the field as well as field trials to determine efficacy in the field as well as any detrimental environmental effects. These studies are currently being carried out in the laboratory of Nguyen Huy Hung. Additional studies are also necessary to examine more essential oil components for biological activity, both individually and in mixtures to assess synergistic activities.

Supplemental Material

sj-docx-1-npx-10.1177_1934578X221110660 - Supplemental material for Pesticidal Activities of Callicarpa and Premna Essential Oils From Vietnam

Supplemental material, sj-docx-1-npx-10.1177_1934578X221110660 for Pesticidal Activities of Callicarpa and Premna Essential Oils From Vietnam by Nguyen Huy Hung, Do Ngoc Dai, Truong Nguyen Cong, Nguyen Anh Dung, Le Duy Linh, Vo Van Hoa, Tran Thu Hien, Nguyen Thi Hong Chuong, Vu Thi Hien, Bui Van Nguyen and William N. Setzer in Natural Product Communications

Supplemental Material

sj-docx-2-npx-10.1177_1934578X221110660 - Supplemental material for Pesticidal Activities of Callicarpa and Premna Essential Oils From Vietnam

Supplemental material, sj-docx-2-npx-10.1177_1934578X221110660 for Pesticidal Activities of Callicarpa and Premna Essential Oils From Vietnam by Nguyen Huy Hung, Do Ngoc Dai, Truong Nguyen Cong, Nguyen Anh Dung, Le Duy Linh, Vo Van Hoa, Tran Thu Hien, Nguyen Thi Hong Chuong, Vu Thi Hien, Bui Van Nguyen and William N. Setzer in Natural Product Communications

Supplemental Material

sj-docx-3-npx-10.1177_1934578X221110660 - Supplemental material for Pesticidal Activities of Callicarpa and Premna Essential Oils From Vietnam

Supplemental material, sj-docx-3-npx-10.1177_1934578X221110660 for Pesticidal Activities of Callicarpa and Premna Essential Oils From Vietnam by Nguyen Huy Hung, Do Ngoc Dai, Truong Nguyen Cong, Nguyen Anh Dung, Le Duy Linh, Vo Van Hoa, Tran Thu Hien, Nguyen Thi Hong Chuong, Vu Thi Hien, Bui Van Nguyen and William N. Setzer in Natural Product Communications

Footnotes

Acknowledgments

W.N.S. participated in this work as part of the activities of the Aromatic Plant Research Center (APRC, ).

Declaration of Conflicting Interests

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

Funding

The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research was funded by NAFOSTED (Vietnam), grant number 106.03-2019.25.

ORCID iD

William N. Setzer

Supplemental material

Supplemental material for this article is available online.

References

Hodgson

Levi

. Pesticides: an important but underused model for the environmental health sciences. Environ Health Perspect. 1996;104(Suppl. 1):97–106. doi:10.1289/ehp.96104s197

Vontas

Kioulos

Pavlidi

Morou

della Torre

Ranson

. Insecticide resistance in the major dengue vectors Aedes albopictus and Aedes aegypti. Pestic Biochem Physiol. 2012;104(2):126‐131. doi:10.1016/j.pestbp.2012.05.008

Liu

. Insecticide resistance in mosquitoes: impact, mechanisms, and research directions. Annu Rev Entomol. 2015;60(1):537‐559. doi:10.1146/annurev-ento-010814-020828

Lam

PKS

Whitfield

Edge

. Resistance to Millettia molluscicide in Biomphalaria glabrata: a quantitative genetical approach. Parasitology. 1989;98(1):17‐20. doi:10.1017/S0031182000059643

Silva

Dória

GAA

Maia

, et al. Effects of essential oils on Aedes aegypti larvae: alternatives to environmentally safe insecticides. Bioresour Technol. 2008;99(8):3251‐3255. doi:10.1016/j.biortech.2007.05.064

Pereira

LPLA

Ribeiro

ECG

Brito

MCA

, et al. Essential oils as molluscicidal agents against schistosomiasis transmitting snails - A review. Acta Trop. 2020;209:105489. doi:10.1016/j.actatropica.2020.105489

Pavela

. Essential oils for the development of eco-friendly mosquito larvicides: a review. Ind Crop Prod. 2015;76:174‐187.

Cowie

Thiengo

. The apple snails of the Americas (Mollusca: Gastropoda: Ampullariidae: Asolene, Felipponea, Marisa, Pomacea, Pomella): a nomenclatural and type catalog. Malacologia. 2003;45(1):41‐100.

Chen

Tong

Zhang

, et al. Loop-mediated isothermal amplification: rapid detection of Angiostrongylus cantonensis infection in Pomacea canaliculata. Parasites and Vectors. 2011;4(1):204. doi:10.1186/1756-3305-4-204

10.

Komalamisra

Nuamtanong

Dekumyoy

. Pila ampullacea and Pomacea canaliculata, as new paratenic hosts of Gnathostoma spinigerum. Southeast Asian J Trop Med Public Health. 2009;40(2):243‐246.

11.

Mozzer

Coaglio

Dracz

Ribeiro

VMA

Lima

. The development of Angiostrongylus vasorum (Baillet, 1866) in the freshwater snail Pomacea canaliculata (Lamarck, 1822). J Helminthol. 2015;89(6):755‐759. doi:10.1017/S0022149X14000856

12.

Chobchuenchom

Bhumiratana

. Isolation and characterization of pathogens attacking Pomacea canaliculata. World J Microbiol Biotechnol. 2003;19(9):903‐906. doi:10.1023/B:WIBI.0000007312.97058.48

13.

Dung

Madsen

The

. Distribution of freshwater snails in family-based VAC ponds and associated waterbodies with special reference to intermediate hosts of fish-borne zoonotic trematodes in Nam Dinh province, Vietnam. Acta Trop. 2010;116(1):15‐23. doi:10.1016/j.actatropica.2010.04.016

14.

Nguyen

PTX

Van Hoang

Dinh

HTK

, et al Insights on foodborne zoonotic trematodes in freshwater snails in North and Central Vietnam. Parasitol Res. 2021;120(3):949‐962. doi:10.1007/s00436-020-07027-1

15.

Doanh

Van Hien

Dung

Loan

. Infection status and molecular identification of digenean cercariae in snails in Kim Son district, Ninh Binh province and Ba Vi district, Ha Noi. Acad J Biol. 2019;41(3):31‐38. doi:10.15625/2615-9023/v41n3.13893

16.

Chai

J-Y

Shin

E-H

Lee

S-H

Rim

H-J

. Foodborne intestinal flukes in Southeast Asia. Korean J Parasitol. 2009;47:S69‐S102. doi:10.3347/kjp.2009.47.S.S69

17.

Shaharom-Harrison

Seman

Suhairi

. Laboratory experimental infection of the freshwater snail Gyraulus convexiusculus (Hutton, 1849) and the bighead carp Aristichthys nobilis (Richardson, 1845) with the blood fluke Sanguinicola armata Plehn, 1905. In: Bondad-Reantaso

Jones

Corsin

Aoki

, eds. Diseases in Asian Aquaculture VII. Fish Health Section, Asian Fisheries Society; 2011:63‐72.

18.

Sanil

Janardanan

. Furcocercous cercariae infecting freshwater snails in Malabar: two new species from Lymnea luteola Lamarck and Gyraulus convexiusculus (Hutton). J Parasit Dis. 2018;42(2):220‐225. doi:10.1007/s12639-018-0987-x

19.

Thapar

. The life history of Olveria indica, an amphistome parasite from the rumen of Indian cattle. J Helminthol. 1961;35(S1):179‐186. doi:10.1017/S0022149X00017739

20.

Chuboon

Wongsawad

. Molecular identification of trematode, Haplorchis taichui cercariae in Tarebia granifera snail using ITS2 sequences. J Yala Rajabhat Univ. 2013;8(1):22‐30.

21.

Veeravechsukij

Namchote

Neiber

Glaubrecht

Krailas

. Exploring the evolutionary potential of parasites: larval stages of pathogen digenic trematodes in their thiarid snail host Tarebia granifera in Thailand. Zoosystematics Evol. 2018;94(2):425‐460. doi:10.3897/ZSE.94.28793

22.

Mukaratirwa

Hove

Cindzi

Maononga

Taruvinga

Matenga

. First report of an outbreak of the oriental eye-fluke, Philophthalmus gralli (Mathis & Leger 1910), in commercially reared ostriches (Struthio camelus) in Zimbabwe. Onderstepoort J Vet Res. 2005;72(3):203‐206. doi:10.4102/ojvr.v72i3.197

23.

Paupy

Delatte

Bagny

Corbel

Fontenille

. Aedes albopictus, an arbovirus vector: from the darkness to the light. Microbes Infect. 2009;11(14-15):1177‐1185. doi:10.1016/j.micinf.2009.05.005

24.

Chouin-Carneiro

Vega-Rua

Vazeille

, et al. Differential susceptibilities of Aedes aegypti and Aedes albopictus from the Americas to Zika virus. PLoS Negl Trop Dis. 2016;10(3):e0004543. doi:10.1371/journal.pntd.0004543

25.

Diaz

Ré

Vázquez

, et al. Genotype III Saint Louis encephalitis virus outbreak, Argentina, 2005. Emerg Infect Dis. 2006;12(11):1752‐1754. doi:10.3201/eid1211.060486

26.

Hribar

Vlach

Demay

, et al. Mosquitoes infected with West Nile Virus in the Florida Keys, Monroe County, Florida, USA. J Med Entomol. 2003;40(3):361‐363. doi:10.1603/0022-2585-40.3.361

27.

Franca

RFO

Neves

MHL

Ayres

CFJ

Melo-Neto

Filho

SPB

. First international workshop on Zika virus held by Oswaldo Cruz Foundation FIOCRUZ in northeast Brazil March 2016 – A meeting report. PLoS Negl Trop Dis. 2016;10(6):e0004760. doi:10.1371/journal.pntd.0004760

28.

World Health Organization W. Progress Report 2000–2009 and Strategic Plan 2010–2020 of the Global Programme to Eliminate Lymphatic Filariasis: Halfway towards Eliminating Lymphatic Filariasis. Geneva, Switzerland: World Health Organization; 2010.

29.

Hung

Huong

Chung

, et al. Callicarpa species from central Vietnam: essential oil compositions and mosquito larvicidal activities. Plants. 2020;9(1):113. doi:10.3390/plants9010113

30.

Hung

Huong

Chung

, et al. Premna species in Vietnam: essential oil compositions and mosquito larvicidal activities. Plants. 2020;9(9):1130. doi:10.3390/plants9091130

31.

Dias

Moraes

DFC

. Essential oils and their compounds as Aedes aegypti L. (Diptera: Culicidae) larvicide: review. Parasitol Res. 2014;113:565‐592. doi:10.1007/s00436-013-3687-6

32.

Hung

Satyal

, et al. Chemical compositions of Crassocephalum crepidioides essential oils and larvicidal activities against Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus. Nat Prod Commun. 2019;14(6):1934578X19850033. doi:10.1177/1934578X19850033

33.

Huong

Chung

Huong

, et al. Essential oils of Zingiber species from Vietnam: chemical compositions and biological activities. Plants. 2020;9(10):1269. doi:10.3390/plants9101269

34.

Hung

Dai

Satyal

, et al. Lantana camara L. Essential oils from Vietnam: chemical composition, molluscicidal, and mosquito larvicidal activity. Chem Biodivers. 2021;18(5):e2100145. doi:10.1002/cbdv.202100145

35.

Arriaga

ÂMC

Rodrigues

FEA

Lemos

, et al. Composition and antioxidant activity of essential oils of Stemodia maritima L. Nat Prod Commun. 2007;2(12):1237‐1239.

36.

Mendes

Martins

Valbon

, et al. Larvicidal effect of essential oils from Brazilian cultivars of guava on Aedes aegypti L. Ind Crops Prod. 2017;108:684‐689. doi:10.1016/j.indcrop.2017.07.034

37.

de Oliveira

Simões

Lima

CAP

, et al. Essential oil of Piper purusanum C.DC (Piperaceae) and its main sesquiterpenes: biodefensives against malaria and dengue vectors, without lethal effect on non-target aquatic fauna. Environ Sci Pollut Res. 2022. doi:10.1007/s11356-022-19196-w

38.

Aguiar

JCD

Santiago

GMP

Lavor

, et al. Chemical constituents and larvicidal activity of Hymenaea courbaril fruit peel. Nat Prod Commun. 2010;5(12):1977‐1980.

39.

Andrade-Ochoa

Sánchez-Aldana

Chacón-Vargas

, et al. Oviposition deterrent and larvicidal and pupaecidal activity of seven essential oils and their major components against Culex quinquefasciatus Say (Diptera: culicidae): synergism – antagonism effects. Insects. 2018;9(1):25. doi:10.3390/insects9010025

40.

Cetin

Yanikoglu

Cilek

. Larvicidal activity of selected plant hydrodistillate extracts against the house mosquito, Culex pipiens, a West Nile virus vector. Parasitol Res. 2011;108(4):943‐948. doi:10.1007/s00436-010-2136-z

41.

Evergetis

Michaelakis

Kioulos

Koliopoulos

Haroutounian

. Chemical composition and larvicidal activity of essential oils from six Apiaceae family taxa against the West Nile virus vector Culex pipiens. Parasitol Res. 2009;105(1):117‐124. doi:10.1007/s00436-009-1370-8

42.

Vourlioti-Arapi

Michaelakis

Evergetis

Koliopoulos

Haroutounian

. Essential oils of indigenous in Greece six Juniperus taxa: chemical composition and larvicidal activity against the West Nile virus vector Culex pipiens. Parasitol Res. 2012;110(5):1829‐1839. doi:10.1007/s00436-011-2706-8

43.

Giatropoulos

Pitarokili

Papaioannou

, et al. Essential oil composition, adult repellency and larvicidal activity of eight Cupressaceae species from Greece against Aedes albopictus (Diptera: Culicidae). Parasitol Res. 2013;112(3):1113‐1123. doi:10.1007/s00436-012-3239-5

44.

World Health Organization W. UNDP/World Bank/WHO Special Programme for Research and Training in Tropical Diseases. Scientific working group on plant molluscicides. https://apps.who.int/iris/handle/10665/60086. Published 1983. Accessed March 12, 2021.

45.

Tavares

Silva

MVB

Queiroga

, et al. Composition and molluscicidal properties of essential oils from leaves of Xylopia langsdorffiana A. St. Hil. Et tul. (Annonaceae). J Essent Oil Res. 2007;19(3):282‐284. doi:10.1080/10412905.2007.9699281

46.

Saad

MMG

Abou-Taleb

. Chemical composition, fumigant toxicity and biochemical effects of essential oils on Spodoptera littoralis (Lepidoptera: Noctuidae) and Theba pisana (Mollusca: Gastropoda: Helicidae). Egypt J Plant Prot Res. 2015;3(1):1‐20.

47.

Coutinho

Dias

Barbosa-Filho

, et al. Composition and molluscicidal activity of the essential oil from the stem bark of Ocotea bracteosa (Meisn.) Mez. J Essent Oil Res. 2007;19(5):482‐484. doi:10.1080/10412905.2007.9699958

48.

Júnior

Núñez

EGF

Santos

, et al. Study of seasonality and location effects on the chemical composition of essential oils from Eugenia uniflora leaves. J Med Plants Res. 2021;15(7):321‐329. doi:10.5897/jmpr2021.7135

49.

Finney

. Probit Analysis. Reissue , ed. Cambridge University Press; 2009.

50.

Hung

Dai

Satyal

Chung

Van Nguyen

Setzer

. Chemical composition of essential oils from leaves of Vitex negundo L. growing in Viet Nam and larvicidal activity against Aedes aegypti L. Vietnam J Sci Technol. 2020;58(6A):142‐157. doi:10.15625/2525-2518/58/6A/15499

Supplementary Material

Please find the following supplemental material available below.

For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.

For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.

0.00 MB

1.09 MB

0.02 MB