Sage Journals: Discover world-class research

Abstract

This study investigated the chemical composition, and antimicrobial activity against food-borne pathogens of the essential oil isolated from the heartwood of Calocedrus formosana from Taiwan. The oil, isolated by hydrodistillation in a Clevenger-type apparatus, was characterized using GC–FID and GC–MS. The major constituents were τ-muurolol (16.1%), α-cadinol (11.1%), α-terpineol (10.6%), thymol (8.5%), and β-thujaplicin (4.5%). The oil demonstrated strong activity against food-borne bacterial and fungal pathogens, and, to determine the source compounds responsible for this activity, the main components were individually evaluated. The most active source compounds were determined to be τ-muurolol, α-cadinol, thymol, and β-thujaplicin.

Keywords

heartwood essential oil food-borne pathogens

Numerous essential oil compounds have antibacterial, antifungal, insecticidal, and medicinal functionality.^1

-7 There has been a recent worldwide increase in the number of reported cases of infectious diseases, especially those that are caused by microbial contamination of foods.⁸ During the processes for the production and sale of food, it can be infected with different microorganisms, such as Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, S. epidermidis, Bacillus subtilis, Vibrio parahaemolyticus, Aspergillus niger, and Chaetomium globosum, which can cause food spoilage, food poisoning, and other problems.⁹ Therefore, nowadays, synthetic antimicrobial agents are used to control microbial growth in food and to reduce the incidence of food poisoning and spoilage. However, synthetic chemicals produce residual compounds so, instead of their use, plant natural products have been utilized. Plant essential oils are used as antibacterial agents to inhibit food-borne pathogens. These products are thought to be safer, non-toxic, well tolerated in the human body, and the demand for these is increasingly accepted.^9,10

Calocedrus formosana Florin (=C. macrolepis var. formosana) is an indigenous coniferous tree in Taiwan.¹¹ It is one of the 5 “precious” conifers of Taiwan.¹² Many previous studies have shown that the leaf, bark and seed essential oils and extracts of C. formosana have antimicrobial, antioxidant, anti-inflammatory, and anti-mosquito larvicide properties,^13

-21 but no study has determined the chemical composition and biological activity of the essential oil of C. formosana heartwood.

This study used hydrodistillation to obtain the essential oil of C. formosana heartwood and its chemical composition was determined using gas chromatography-flame ionization detection (GC–FID) and gas chromatography-mass spectrometry (GC–MS). The second part of this study determined the activity of the oil against food-borne bacterial and fungal pathogens. The purpose of this study was to establish a chemical basis for the effective multipurpose utilization of the species.

Results and Discussion

The essential oil obtained from the heartwood of C. formosana was a highly aromatic, dark-yellow-colored liquid. The yield of oil was 3.34 ± 0.08 ml/100 g, calculated on a moisture free basis. Table 1 shows the constituents, the percentage composition and the retention index (RI) values, which are listed in order of elution from the DB-5MS capillary column. A total of 65 compounds were identified from the hydrodistilled heartwood oil (Table 1). Among these, 2.0% were monoterpene hydrocarbons, 33.8% oxygenated monoterpenes, 17.1% sesquiterpene hydrocarbons, 35.0% oxygenated sesquiterpenes, 0.8% one diterpene, and 10.3% two other compounds. τ-Muurolol (16.1%) and α-cadinol (11.1%) were the major oxygenated sesquiterpenes, and α-terpineol (10.6%) and β-thujaplicin (4.5%) the main oxygenated monoterpenes. Of the others, thymol (8.5%) was the major compound. This is the first report of the heartwood oil composition of C. formosana.

Table 1

Chemical Composition of the Heartwood Essential Oil of Calocedrus Formosana.

Compound I.D.	RI^a	RI^b	Concentration (%)	Identification⁸
α-Pinene	937	939	0.3 ± 0.01	MS,RI,ST
Camphene	953	954	0.1 ± 0.01	MS,RI,ST
trans-p-Menthane	977	979	0.1 ± 0.01	MS,RI,ST
β-Pinene	978	979	0.1 ± 0.01	MS,RI,ST
Myrcene	987	990	0.1 ± 0.01	MS,RI,ST
1,4-Cineole	1014	1014	0.4 ± 0.02	MS,RI,ST
p-Cymene	1023	1024	0.3 ± 0.01	MS,RI,ST
Limonene	1027	1029	0.2 ± 0.02	MS,RI,ST
1,8-Cineole	1030	1031	0.2 ± 0.01	MS,RI,ST
γ-Terpinene	1056	1059	0.1 ± 0.01	MS,RI,ST
p-Mentha-3,8-diene	1069	1072	0.1 ± 0.01	MS,RI,ST
Fenchone	1086	1086	1.5 ± 0.09	MS,RI
p-Mentha-2,4(8)-diene	1087	1088	0.6 ± 0.02	MS,RI
endo-Fenchol	1114	1116	1.8 ± 0.02	MS,RI,ST
exo-Fenchol	1120	1121	0.1 ± 0.02	MS,RI,ST
1-Terpineol	1131	1133	0.5 ± 0.02	MS,RI
Camphor	1145	1146	2.8 ± 0.10	MS,RI,ST
Camphene hydrate	1150	1149	0.1 ± 0.01	MS,RI
neo-3-Thujanol	1152	1153	2.5 ± 0.12	MS,RI
Isoborneol	1160	1160	0.3 ± 0.01	MS,RI,ST
Borneol	1170	1169	4.4 ± 0.13	MS,RI,ST
Terpinen-4-ol	1175	1177	0.4 ± 0.01	MS,RI,ST
α-Terpineol	1190	1188	10.6 ± 0.32	MS,RI,ST
γ-Terpineol	1198	1199	3.3 ± 0.18	MS,RI,ST
m-Cumenol	1228	1227	1.8 ± 0.09	MS,RI
Isobornyl acetate	1286	1285	0.1 ± 0.01	MS,RI
Bornyl acetate	1289	1288	0.1 ± 0.01	MS,RI,ST
Thymol	1291	1290	8.5 ± 0.05	MS,RI,ST
Citronellic acid	1312	1313	0.1 ± 0.01	MS,RI,ST
α-Cubebene	1350	1348	0.2 ± 0.01	MS,RI,ST
α-Terpinyl acetate	1351	1349	0.1 ± 0.01	MS,RI,ST
Isoledene	1375	1376	0.1 ± 0.01	MS,RI
β-Elemene	1388	1390	1.0 ± 0.03	MS,RI
β-Caryophyllene	1418	1419	0.1 ± 0.01	MS,RI,ST
α-Humulene	1453	1454	0.2 ± 0.01	MS,RI,ST
cis-Muurola-4(14),5-diene	1466	1467	0.1 ± 0.01	MS,RI
β-Thujaplicin	1476	1477	4.5 ± 0.18	MS,RI,ST
γ-Muurolene	1478	1479	1.8 ± 0.09	MS,RI
γ-Himachalene	1481	1482	0.6 ± 0.01	MS,RI
β-Selinene	1490	1490	1.1 ± 0.08	MS,RI
α-Muurolene	1501	1500	2.7 ± 0.09	MS,RI,ST
γ-Cadinene	1513	1513	2.8 ± 0.12	MS,RI
δ-Cadinene	1523	1523	2.9 ± 0.11	MS,RI
cis-Calamenene	1528	1529	1.5 ± 0.06	MS,RI
trans-Cadina-1(2),4-diene	1533	1534	0.8 ± 0.01	MS,RI
α-Cadinene	1538	1538	0.7 ± 0.01	MS,RI,ST
α-Calacorene	1546	1545	0.5 ± 0.01	MS,RI,ST
Elemol	1550	1549	0.6 ± 0.01	MS,RI,ST
Gleenol	1588	1587	0.4 ± 0.01	MS,RI
Guaiol	1600	1600	0.6 ± 0.01	MS,RI,ST
1,10-di-epi-Cubenol	1621	1619	0.7 ± 0.02	MS,RI
10-epi-γ-Eudesmol	1625	1623	0.8 ± 0.01	MS,RI
1-epi-Cubenol	1629	1628	1.3 ± 0.01	MS,RI
γ-Eudesmol	1633	1632	0.6 ± 0.01	MS,RI
τ-Muurolol	1643	1642	16.1 ± 0.28	MS,RI
α-Cadinol	1655	1654	11.1 ± 0.38	MS,RI,ST
5-neo-Cedranol	1686	1685	0.6 ± 0.01	MS,RI
Eudesm-7(11)-en-4-ol	1701	1700	0.2 ± 0.01	MS,RI
Guaiol acetate	1728	1726	0.1 ± 0.01	MS,RI
Khusimol	1743	1742	0.6 ± 0.01	MS,RI
8-α−11-Elemodiol	1748	1747	0.1 ± 0.01	MS,RI
14-hydroxy-α-Muurolene	1781	1780	0.4 ± 0.01	MS,RI
β-Eudesmol acetate	1793	1792	0.3 ± 0.01	MS,RI
α-Eudesmol acetate	1796	1795	0.5 ± 0.01	MS,RI
trans-Ferruginol	2333	2332	0.8 ± 0.02	MS,RI,ST
Monoterpene hydrocarbons (%)			2.0
Oxygenated monoterpenes (%)			33.8
Sesquiterpene hydrocarbons (%)			17.1
Oxygenated sesquiterpenes (%)			35.0
Diterpenes (%)			0.8
Others (%)			10.3
Identified compounds (%)			99.0

^aRetention index, experimental: n-alkanes (C9-C24) were used as reference points in the calculation of relative retention indices.

^bRetention index on a DB-5MS column with reference to n-alkanes.^22,23

^cMS, NIST and Wiley library spectra, and the literature; RI, Retention index; ST, authentic standard compounds.

The heartwood oil of C. formosana was tested against 7 food-borne bacterial pathogens, including the 3 Gram-positive bacteria, Bacillus cereus, Staphylococcus aureus and S. epidermidis, and 4 Gram-negative bacteria, Escherichia coli, Enterobacter aerogenes, Pseudomonas aeruginosa and Vibrio parahaemolyticus. The inhibition zone, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) values for the essential oil against the tested bacteria are listed in Table 2. The results show that the essential oil had good antibacterial activity against all tested microorganisms. The most sensitive were B. cereus, S. aureus, S. epidermidis, and E. coli, with inhibition zones of 53‐65 mm, MIC values of 31.25‐62.5 μg/mL, and MBC values of 62.5‐125 μg/mL.

Table 2

Antibacterial Activity of the Heartwood Essential Oil From Calocedrus formosana.

Bacterial species^a	C. formosana			Compounds^e										Antibiotics^f
	Heartwood			1		2		3		4		5		X	Y	Z
	IZ^b	MIC^c	MBC^d	MIC	MBC	MIC	MBC	MIC	MBC	MIC	MBC	MIC	MBC	IZ	IZ	IZ
I	53 ± 0.3	31.25	62.5	>1000	>1000	62.5	125	125	250	3.9	15.62	7.81	15.62	22 ± 0.8	-^g	21 ± 0.4
II	65 ± 0.1	31.25	62.5	>1000	>1000	31.25	62.5	62.5	125	3.9	15.62	7.81	15.62	21 ± 0.4	-	24 ± 0.8
III	58 ± 0.2	31.25	62.5	>1000	>1000	31.25	62.5	62.5	125	3.9	15.62	7.81	15.62	34 ± 0.4	-	31 ± 0.8
IV	56 ± 0.3	31.25	62.5	>1000	>1000	125	250	750	1000	31.25	62.5	15.62	31.25	-	22 ± 0.8	11 ± 0.4
V	45 ± 0.3	62.5	125	>1000	>1000	125	250	250	500	31.25	62.5	15.62	31.25	10 ± 0.4	-	12 ± 0.4
VI	48 ± 0.1	62.5	125	>1000	>1000	125	250	250	500	62.5	125	3.9	15.62	-	12 ± 0.8	9 ± 0.4
VII	36 ± 0.3	125	250	>1000	>1000	500	750	1000	>1000	125	250	15.62	31.25	-	13 ± 0.8	10 ± 0.8

^aI. B. cereus, II. S. cereus. III. S. epidermidis, IV. E. coli, V. E. aerogenes, VI. P. aeruginosa, VII. V. parahaemolyticus.

^bInhibition zone diameter (mm), including diameter of sterile disk (6 mm); values are given as mean ± SD.

^cMinimum inhibitory concentration values as μg/mL.

^dMinimal bactericidal concentration values as μg/mL.

^e1. α-Terpineol (≥99.0%), 2. τ-Muurolol (100.0%), 3. α-Cadinol (100.0%), 4. Thymol (≥99.5%), 5. β-Thujaplicin (≥99.0%), compounds 1, 4, and 5 were purchased from Fluka Co. (Milwaukee, USA). Compounds 2 and 3 were isolated by Ho et al.^24,25

^fX. Tetracycline (30 µg/disk), Y. Gentamicin (10 µg/disk), Z. Amoxicillin (25 µg/disk).

^g-, Inactive.

Kalemba and Kunicka²⁶ deemed that the majority of oxygenated essential oil compounds have antibacterial activity that is usually stronger than that of the oils, and always stronger than that of hydrocarbons. The reason for this is that terpenoids are lipid soluble, and the oxygen-containing compounds with phenol-, alcohol-, and aldehyde-containing functional groups can interfere with enzymatic activities, for instance, effecting, for example, respiratory function. As for inhibition of bacterial growth, these terpenoids can disrupt transduction of protons and affect phosphorylation of ADP, causing inhibition of bacterial growth.²⁷ In our experiments, the essential oil extracted from C. formosana heartwood was mainly composed of oxygenated compounds (oxygenated sesquiterpenes and oxygenated monoterpenes accounted for 68.8% of the total). Hence, the heartwood oil showed excellent anti-bacterial activity.

To determine the compounds that are responsible for the antibacterial activity of C. formosana heartwood oil, the main components were individually tested for antibacterial activity. The results showed that the active compounds are τ-muurolol, α-cadinol, thymol, and β-thujaplicin. τ-Muurolol and α-cadinol are cadinane-type compounds, and the literature reports that this type of compound possesses extensive antibacterial activity.^28,29 Thymol is well known to possess excellent anti-bacterial activity.²⁶ β-Thujaplicin, a tropolone-type compound, is known to possess multiple properties, including anti-oxidation, anti-inflammation, and antibacterial activities.^30
-32 Numerous literature supports that the 4 compounds, τ-muurolol, α-cadinol, thymol, and β-thujaplicin, possess excellent antibacterial activities.^33

-40

The heartwood essential oil was also tested against the 4 food-borne fungal pathogens, Aspergillus niger, Chaetomium globosum, Penicillium citrinum, and Trichoderma viride. Figure 1 shows the antifungal indices for the essential oil of the heartwood oil (at a concentration of 100 µg/mL) against the 4 food-borne fungi. At this concentration, the oil totally inhibited the growth of all 4 fungi. The MIC and IC₅₀ values for the heartwood oil against these pathogens are shown in Table 3. The results clearly demonstrate that the heartwood essential oil of C. formosana exhibits excellent anti-fungal activity. The growth of A. niger, C. globosum, P. citrinum, and T. viride was completely inhibited at concentrations of 75, 50, 50, and 75 µg/mL, respectively.

Figure 1

Anti-food-borne fungal pathogen indices for the heartwood essential oil (100 µg/mL) from Calocedrus formosana.

Table 3

MIC and IC₅₀ Values (Μg/mL) for 5 Major Compounds From Calocedrus Formosana Heartwood Oil Against 4 Food-Borne Pathogenic Fungi.

Fungal species	Heartwood		α-Terpineol		τ-Muurolol		α-Cadinol		Thymol		β-Thujaplicin		Nystatin
Fungal species	MIC	IC₅₀	MIC	IC₅₀	MIC	IC₅₀	MIC	IC₅₀	MIC	IC₅₀	MIC	IC₅₀	MIC	IC₅₀
A. niger	75	38.6	>250	>250	125	75.3	75	48.3	100	32.6	6.25	<6.25	<6.25	<6.25
C. globosum	50	35.8	>250	>250	100	48.6	50	33.6	50	23.1	12.5	20.3	<6.25	<6.25
P. citrinum	50	38.3	>250	>250	125	88.6	100	60.3	25	15.1	25	13.8	<6.25	<6.25
T. viride	75	42.9	>250	>250	125	75.3	75	46.8	25	21.3	12.5	8.13	<6.25	<6.25

Note: Nystatin (50 µg/mL) was used as a positive control.

To determine the compounds of C. formosana heartwood essential oil responsible for the anti-fungal activity, the major components were measured. The anti-fungal indices increased in the order: β-thujaplicin > thymol > α-cadinol> τ-muurolol> α-terpineol. At a concentration of 100 µg/mL, β-thujaplicin, thymol and α-cadinol totally inhibited the growth of the food-borne fungal pathogens. τ-Muurolol, at a concentration of 100 µg/mL, completely inhibited C. globosum and partially inhibited A. niger, P. citrinum, and T. viride; α-terpineol, at 100 µg/mL, slightly inhibited the fungal pathogens (Figure 2).

Figure 2

Anti-food-borne fungal pathogen indices for the 5 main compounds (100 µg/mL) of heartwood essential oil from Calocedrus formosana.

The MIC and IC₅₀ values for α-terpineol, τ-muurolol, α-cadinol, thymol, and β-thujaplicin are shown in Table 3. The results show that the active source compounds are τ-muurolol, α-cadinol, thymol, and β-thujaplicin. Of these, β-thujaplicin has the best antifungal activity. The main mechanism of β-thujaplicin’s antifungal activity may lie in the change wrought by the compound in the permeability of the cell wall, causing leakage of the cell plasma and disrupting chelation of metallic ions in the biosynthesis of fungal enzymes.⁴¹ Previous studies have shown that these compounds are very effective in suppressing fungal growth.^{15,38,39,42

-45} The results show that τ-muurolol, α-cadinol, thymol, and β-thujaplicin of C. formosana heartwood oil are natural fungicides that can be used to control food-borne fungal pathogens.

Conclusion

This study reports that the essential oil extracted from the heartwood of Calocedrus formosana, with its main components of τ-muurolol, α-cadinol, α-terpineol, thymol, and β-thujaplicin, possesses pronounced antimicrobial activity against food-borne pathogens. The essential oil is composed mainly of oxygenated sesquiterpenes and oxygenated monoterpenes. Among these components, τ-muurolol, α-cadinol, thymol, and β-thujaplicin were proven to possess excellent antibacterial and antifungal activities. In the near future, our study should focus on developing a variety of natural anti-pathogen products.

Experimental

Plant Materials

Fresh heartwoods of C. formosana were collected in October 2020 from Chilan Mt in northeast Taiwan (Yilan County, altitude 850 m, latitude (N) 24°40’050’’, longitude (E) 121°39’10’’). The samples were compared with specimen no. ou 5886 from the Herbarium of National Chung-Hsing University and positively identified by Yu Hang-Ming of TFRI. A voucher specimen (CLH- 010) was deposited in the NCHU herbarium. Heartwood of the species was collected for subsequent extraction of essential oil and analysis.

Isolation of Heartwood Essential Oil

Heartwood of C. formosana (1 kg) was hydrodistilled for 3 hours using a Clevenger-type apparatus. The essential oil was then dried with anhydrous sodium sulfate. The oil yields and all test data are shown as the average of triplicate analyses.

Essential Oil Analysis

A Hewlett-Packard HP 6890 gas chromatograph equipped with a DB-5 fused silica capillary column (30 m x 0.25 mm x 0.25 μm film thickness, J&W Scientific) and a FID detector were used for the quantitative determination of oil components. The oven temperature was maintained at 50 °C for 2 minutes and increased to 250 °C at 5 °C/min. The injector temperature was 270 °C. The carrier gas was helium with a flow rate of 1 mL/min. The detector temperature was 250 °C and the split ratio was 1:10. Diluted samples (1.0 µL, 1/100, v/v, in ethyl acetate) were injected manually in split mode. The oil components were identified in terms of retention index (RI)²² and mass spectra, which were obtained using GC/MS analysis on a Hewlett-Packard HP 6890/HP5973 equipped with a DB-5MS fused silica capillary column (30 m x 0.25 mm x 0.25 μm film thickness, J&W Scientific). The GC analysis parameters are listed above and the mass spectra were obtained (full scan mode: scan time: 0.3 s, mass range was m/z 30‐500) in EI mode at 70 eV. All data are shown as the average of triplicate analyses.

Component Identification

The heartwood oil constituents were identified by comparisons of retention index (RI),²² retention time (RT) and mass spectra with those of authentic standards and/or the NIST and Wiley libraries spectra, and literature.^22,23

Antibacterial Activity

The antibacterial properties of the heartwood essential oil and the oil’s main compounds were analyzed using the paper disc diffusion method, minimum inhibition concentration (MIC), and minimum bactericidal concentration (MBC). Discs containing 15 µL and 30 µL of the oil dissolved in dimethylsulfoxide (DMSO) were placed on inoculated plates with test microorganisms. Growth inhibition zones (including a disc diameter of 6 mm) were measured after 24 hours of incubation at 37 °C. Gentamicin, tetracycline, and amoxicillin were used as positive controls. Microbial strains were obtained from the Culture Collection and Research Center of the Food Industry Research and Development Institute, Hsinchu City, Taiwan. The microbial strains included 4 Gram-negative bacteria, E. coli (IFO 3301), E. aerogenes (ATCC 13048), P. aeruginosa (IFO 3080), and V. parahaemolyticus (ATCC 17803), and 3 Gram-positive bacteria, B. cereus (ATCC 11778), S. aureus (ATCC 6538P), and S. epidermidis (ATCC 12228).

The minimum inhibitory concentration (MIC) values were measured using a microdilution broth susceptibility assay, as recommended by NCCLS,⁴⁶ and as reported earlier.²⁴ To determine the minimal bactericidal concentration (MBC), 100 µL of each dilution with no evident growth was spread on Mueller-Hinton agar (MHA). The inoculated Petri dishes and the controls were incubated at 37 °C for 24 hours. The number of colony forming units was counted and compared with that for the control dishes. MBC is defined as the lowest concentration that kills >99.9% of the initial inoculum.⁴⁷

Anti- Food-Borne Fungal Pathogen Assays

The method of Su et al.⁴⁸ was used. The fungi were A. niger (ATCC 6275), Ch. globosum (ATCC 6205), P. citrinum (ATCC 9849), and T. viride (ATCC8678). Microbial strains were obtained from the Culture Collection and Research Center of the Food Industry Research and Development Institute, Hsinchu City, Taiwan. Anti- food-borne fungal assays were performed in triplicate and the data were averaged. Different concentrations of the essential oil (6.25 ~ 250 µg/mL) were added to sterilized potato dextrose agar (PDA). The test plates were incubated at 27 °C. When the mycelium of the fungi reached the edge of the control plate, the anti-food-borne fungal pathogen index was calculated as:

A n t i - f o o d - b o r n e f u n g a l p a t h o g e n i n d e x (%) = (1 - D a ∕ D b) \times 100,

where Da is the diameter of the growth zone in the experimental dish (cm) and Db is the diameter of the growth zone in the control dish (cm).

Nystatin was used as a positive control. Each test was repeated 5 times and the data were averaged. The IC₅₀ values (the concentration in mg per mL that inhibit 50% of mycelium growth) were calculated using probit analysis.

Footnotes

Declaration of Conflicting Interests

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

Funding

The author(s) received no financial support for the research, authorship, and/or publication of this article.

ORCID iD

Chen-Lung Ho

References

Karpouhtsis

Pardali

Feggou

Kokkini

Scouras

ZG.

Mavragani-Tsipidou

. Insecticidal and genotoxic activities of oregano essential oils. J Agric Food Chem. 1998;46(3):1111-1115.doi:10.1021/jf970822o

Beuchat

LR.

Golden

. Antimicrobials occurring naturally in foods. Food Technol. 1989;43:134-142.

Wińska

Mączka

Łyczko

Grabarczyk

Czubaszek

Szumny

. Essential oils as antimicrobial agents-myth or real alternative? Molecules. 2019;24(11):2130.doi:10.3390/molecules24112130

Lang

Buchbauer

. A review on recent research results (2008-2010) on essential oils as antimicrobials and antifungals. A review. Flavour Fragr J. 2012;27(1):13-39.doi:10.1002/ffj.2082

Nazzaro

Fratianni

Coppola

Feo

VD.

Vincenzo

. Essential oils and antifungal activity. Pharmaceuticals. 2017;10(4):86.doi:10.3390/ph10040086

Yang

Isman

MB.

Tak

J-H

. Insecticidal activity of 28 essential oils and a commercial product containing Cinnamomum cassia bark essential oil against Sitophilus zeamais Motschulsky. Insects. 2020;11(8):474. doi:10.3390/insects11080474

Lis-Balchin

Deans

. Bioactivity of selected plant essential oils against Listeria monocytogenes . J Appl Microbiol. 1997;82(6):759-762.doi:10.1046/j.1365-2672.1997.00153.x

9202441

Burt

. Essential oils: their antibacterial properties and potential applications in foods--a review. Int J Food Microbiol. 2004;94(3):223-253.doi:10.1016/j.ijfoodmicro.2004.03.022

15246235

Miladi

Zmantar

Chaabouni

et al. Antibacterial and efflux pump inhibitors of thymol and carvacrol against food-borne pathogens. Microb Pathog. 2016;99:95-100.doi:10.1016/j.micpath.2016.08.008

27521228

10.

Boskovic

Baltic

Ivanovic

et al. Use of essential oils in order to prevent foodborne illnesses caused by pathogens in meat. Tehnologija Mesa. 2013;54(1):14-20.doi:10.5937/tehmesa1301014B

11.

Yang

YP.

Liu

. Manual of Taiwan vascular plants. Council of Agriculture, Executive Yuan; 1999.

12.

Kuo

. The Precious 5 Conifers of Taiwan. Chinese Forestry Association; 1995.

13.

Chang

HT.

Cheng

SS.

Chang

ST.

Tasi

KH.

Chen

. Mosquitocidal activity of leaf essential oil and its components from Calocedrus formosana . Quar J Chin For. 2003;36:73-79.

14.

Chao

K-P.

Hua

K-F.

Hsu

H-Y.

Y-C.

Chang

S-T

. Anti-inflammatory activity of sugiol, a diterpene isolated from Calocedrus formosana bark. Planta Med. 2005;71(4):300-305.doi:10.1055/s-2005-864094

15856404

15.

Cheng

S-S.

C-L.

Chang

H-T.

Kao

Y-T.

Chang

S-T

. Antitermitic and antifungal activities of essential oil of Calocedrus formosana leaf and its composition. J Chem Ecol. 2004;30(10):1957-1967.doi:10.1023/B:JOEC.0000045588.67710.74

15609830

16.

Chang

H-T.

Cheng

Y-H.

C-L.

Chang

S-T.

Chang

T-T.

Y-C

. Antifungal activity of essential oil and its constituents from Calocedrus macrolepis var. formosana Florin leaf against plant pathogenic fungi. Bioresour Technol. 2008;99(14):6266-6270.doi:10.1016/j.biortech.2007.12.005

18206367

17.

Yen

T-B.

Chang

H-T.

Hsieh

C-C.

Chang

S-T

. Antifungal properties of ethanolic extract and its active compounds from Calocedrus macrolepis var. formosana (Florin) heartwood. Bioresour Technol. 2008;99(11):4871-4877.doi:10.1016/j.biortech.2007.09.037

17977717

18.

Wang

S-Y.

J-H.

Cheng

S-S

et al. Antioxidant activity of extracts from Calocedrus formosana leaf, bark, and heartwood. J Wood Sci. 2004;50(5):422-426.doi:10.1007/s10086-003-0580-4

19.

C-L.

Tseng

Y-H.

Wang

EIC

et al. Composition, antioxidant and antimicrobial activities of the seed essential oil of Calocedrus formosana from Taiwan. Nat Prod Commun. 2011;6(1):133-136.21366064

20.

Yen

PL.

Chang

ST.

Huang

SL.

Chang

. Antioxidative lignans from phytochemical extract of Calocedrus formosana Florin. Bioresources. 2012;7:4122-4131.

21.

L-H.

Lee

J-Y

et al. Hinokitiol induces DNA damage and autophagy followed by cell cycle arrest and senescence in gefitinib-resistant lung adenocarcinoma cells. PLoS One. 2014;9(8):e104203. doi:10.1371/journal.pone.0104203

25105411

22.

Adams

. Identification of Essential Oil Components by Gas Chromatography/Quadruple Mass Spectroscopy. Allured; 2001.

23.

Massada

. Analysis of Essential Oil by Gas Chromatography and Spectrometry. Wiley; 1976.

24.

C-L.

Liao

P-C.

Hsu

K-P.

Wang

EI-C.

Dong

W-C.

Y-C

. Composition and antimicrobial and anti-wood-decay fungal activities of the leaf essential oils of Machilus pseudolongifolia from Taiwan. Nat Prod Commun. 2010;5(7):1143-1146.20734960

25.

C-L.

Hsu

K-P.

Wang

EI-C.

Lin

C-Y.

Y-C

. Composition and anti-wood-decay fungal activities of the leaf essential oil of Machilus philippinensis from Taiwan. Nat Prod Commun. 2010;5(2):337-340.20334154

26.

Kalemba

Kunicka

. Antibacterial and antifungal properties of essential oils. Curr Med Chem. 2003;10:813-829.doi:10.2174/0929867033457719

12678685

27.

Knobloch

Pauli

Iberl

Weigand

Weis

. Antibacterial and antifungal properties of essential oil components. Journal of Essential Oil Research. 1989;1(3):119-128.doi:10.1080/10412905.1989.9697767

28.

Yatagai

Sato

Yamaguchi

Morita

. Components of Chamaecyparis fossil wood having activity against Streptococcus mutans RIMD 3125001. Mokuzai Gakkaishi. 1984;30:240-243.

29.

Nabeta Katayama

K. K.

Matsubara

et al. Oxygenated sesquiterpenes from needles of Korea pine (Pinus koraiensis Sieb. et Zucc. Mokuzai Gakkaishi. 1992;38:963-971.

30.

Morita

Sakagami

Okabe

Ohe

Inamori

Ishida

. The mechanism of the bactericidal activity of hinokitiol. Biocontrol Sci. 2007;12(3):101-110.doi:10.4265/bio.12.101

17927050

31.

Wang

T-H.

Hsia

S-M.

C-H

et al. Evaluation of the antibacterial potential of liquid and vapor phase phenolic essential oil compounds against oral microorganisms. PLoS One. 2016;11(9):e0163147. doi:10.1371/journal.pone.0163147

27681039

32.

Domon

Hiyoshi

Maekawa

et al. Antibacterial activity of hinokitiol against both antibiotic-resistant and -susceptible pathogenic bacteria that predominate in the oral cavity and upper airways. Microbiol Immunol. 2019;63(6):213-222.doi:10.1111/1348-0421.12688

31106894

33.

Griffin

SG.

Wyllie

SG.

Markham

JL.

Leach

. The role of structure and molecular properties of terpenoids in determining their antimicrobial activity. Flavour Fragr J. 1999;14(5):322-332.doi:10.1002/(SICI)1099-1026(199909/10)14:5<322::AID-FFJ837>3.0.CO;2-4

34.

Y-C.

Hsu

K-P.

Wang

EI-C.

C-L

. Composition, in vitro cytotoxic, and antimicrobial activities of the flower essential oil of Diospyros discolor from Taiwan. Nat Prod Commun. 2015;10(7):1311-1314.26411038

35.

Zhou

B-P.

Pei

R-S.

. The antibacterial mechanism of carvacrol and thymol against Escherichia coli . Lett Appl Microbiol. 2008;47(3):174-179.doi:10.1111/j.1472-765X.2008.02407.x

19552781

36.

Arima

Nakai

Hayakawa

Nishino

. Antibacterial effect of beta-thujaplicin on staphylococci isolated from atopic dermatitis: relationship between changes in the number of viable bacterial cells and clinical improvement in an eczematous lesion of atopic dermatitis. J Antimicrob Chemother. 2003;51(1):113-122.doi:10.1093/jac/dkg037

12493795

37.

Coombs

RW.

Trust

. Antibacterial activity of β-thujaplicin. Can J Microbiol. 2011;19(11):1341-1346.

38.

Fotopoulou

Ćirić

Kritsi

et al. Antimicrobial/antibiofilm activity and cytotoxic studies of β-thujaplicin derivatives. Arch Pharm. 2016;349(9):698-709.doi:10.1002/ardp.201600095

39.

Marchese

Orhan

IE.

Daglia

et al. Antibacterial and antifungal activities of thymol: a brief review of the literature. Food Chem. 2016;210:402-414.doi:10.1016/j.foodchem.2016.04.111

27211664

40.

Inoue

Suzuki

Murata

Nomura

Isshiki

Kanamoto

. Evaluation of antibacterial activity expression of the hinokitiol/cyclodextrin complex against bacteria. ACS Omega. 2020;5(42):27180-27187.doi:10.1021/acsomega.0c03222

33134678

41.

Kwon

Kim

H-S.

Kim

H-W.

Lee

DW.

Choi

Y-H

. Antifungal activities of β-thujaplicin originated in Chamaecyparis obtusa . J Appl Biol Chem. 2017;60(3):265-269.doi:10.3839/jabc.2017.042

42.

de Castro

RD.

de Souza

TMPA.

Bezerra

LMD.

Ferreira

GLS.

de Brito Costa

EMM.

Cavalcanti

. Antifungal activity and mode of action of thymol and its synergism with nystatin against Candida species involved with infections in the oral cavity: an in vitro study. BMC Complement Altern Med. 2015;15:417. doi:10.1186/s12906-015-0947-2

26601661

43.

YC.

Hsu

KP.

. Composition, in vitro anti-mildew fungal activities of the heartwood essential oil of Chamaecyparis formosensis from Taiwan. Nat Prod Commun. 2018;13:1363-1366.

44.

Wang

S-Y.

C-L.

Chu

F-H

et al. Chemical composition and antifungal activity of essential oil isolated from Chamaecyparis formosensis Matsum. wood. Holzforschung. 2005;59(3):295-299.doi:10.1515/HF.2005.049

45.

Kwon

Kim

H-S.

Kim

H-W.

Lee

DW.

Choi

Y-H

. Antifungal activities of β-thujaplicin originated in Chamaecyparis obtusa . J Appl Biol Chem. 2017;60(3):265-269.doi:10.3839/jabc.2017.042

46.

NCCLS National Committee for Clinical Laboratory Standards . Performance standards for antimicrobial susceptibility testing. 9th International Supplement, Wayne PA., M100-S9; 1999.

47.

Chikezie

. Determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using a novel dilution tube method. Afr J Microbiol Res. 2017;11(23):977-980.doi:10.5897/AJMR2017.8545

48.

YC.

CL.

Wang

EIC.

Chang

. Antifungal activities and chemical compositions of essential oils from leaves of four eucalypts. Taiwan J For Sci. 2006;21:49-61.

Chemical Composition and Antimicrobial Activity Against Food-Borne Pathogens of Calocedrus formosana Heartwood Essential Oil

Abstract

Keywords

Results and Discussion

Conclusion

Experimental

Plant Materials

Isolation of Heartwood Essential Oil

Essential Oil Analysis

Component Identification

Antibacterial Activity

Anti- Food-Borne Fungal Pathogen Assays

Footnotes

Declaration of Conflicting Interests

Funding

ORCID iD

References