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Camellia pleurocarpa (Gagnep.) Sealy, a species of yellow camellia indigenous to Vietnam, was investigated for its essential oil properties in this study. Hydrodistillation of its leaves yielded a complex mixture rich in sesquiterpenes and diterpenes. Chemical analysis identified 50 constituents, with notable compounds including spathulenol (13.26%), phytol (9.94%), and α-selinene (5.34%). The essential oil exhibited significant antimicrobial activity against three Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus; one Gram-negative bacterium Pseudomonas aeruginosa; and one yeast Candida albicans, with minimum inhibitory concentration (MIC) values ranging from 16 to 32 μg/mL and half-maximal inhibitory concentration (IC50) values ranging from 7.26 to 16.23 μg/mL. Furthermore, it demonstrated larvicidal potential against Aedes aegypti and Culex quinquefasciatus mosquitoes, with LC50 values ranging from 13.49 to 28.95 μg/mL and LC90 values ranging from 28.29 to 53.24 μg/mL. These findings underscore the promising antimicrobial and mosquito larvicidal properties of C. pleurocarpa essential oil, suggesting its potential as a natural alternative in combating microbial infections and controlling mosquito-borne diseases. This study represents the first comprehensive report on the chemical compositions and bioactivities of C. pleurocarpa essential oil. [ABSTRACT FROM AUTHOR]

The present study aims to describe the chemical composition of essential oils from three Vietnamese Annonaceae species, Meiogyne virgata, M. vietnamica, and Orophea polycarpa, and their antimicrobial activity. Essential oils were extracted by hydro-distillation. From the GC-FID/MS (gas chromatography-flame ionization detection and mass spectrometry) analysis, the leaf essential oil of M. virgata was reported to contain the major compound germacrene D (42.48%). Spathulenol (24.51%), bicyclogermacrene (18.58%), β-selinene (11.14%), and germacrene D (8.20%) can be seen as the main compound in M. vietnamica leaf essential oil. α-Phellandrene (39.35%), bicyclogermacrene (13.07%), β-phellandrene (10.87%), and limonene (8.27%) represented O. polycarpa leaf essential oil. Essential oil of M. virgata leaves exhibited strong antimicrobial activity against the Gram (+) bacterium Bacillus subtilis ATCC 5230, the Gram (-) bacterium Escherichia coli ATCC 8739, and the fungus Aspergillus niger ATCC 9587 with the same MIC value of 16 μg/mL. The docking method showed that germacrene D has the ΔGbinding (binding affinity) values of –6.68, –5.265, and –5.602 kcal/mol with the proteins E. coli DNA gyrase, B. subtilis TasA, and A. niger PhyA, respectively. Alkyl and pi-alkyl interactions are the main contributors to the binding affinity between the studied proteins and ligands. Furthermore, germacrene D is predicted to have low toxicity and is not active against any of the considered organ targets. [ABSTRACT FROM AUTHOR]

The chemical constituents and antimicrobial activity of the essential oils isolated from the leaves of Machilus cicatricosa S.K. Lee and Machilus bonii Lecomte from Vietnam were studied and reported. The techniques of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS) were used to characterize the chemical constituents of the essential oil while the microdilution assay was used to evaluate the antimicrobial activity. The main constituents of the leaf oil of M. cicatricosa were α-pinene (20.6%), bicyclogermacrene (15.2%), linalool (14.9%), and β-pinene (8.4%). On the other hand (E)-β-ocimene (26.3%), bicyclogermacrene (23.6%) and (E)-nerolidol (9.1%) were the major constituents of M. bonii leaf essential oil. The studied essential oils displayed antimicrobial activity against Enterococcus faecalis ATCC 29212, and Staphylococcus aureus ATCC 25923, with minimum inhibitory concentration (MIC) value of 64.0 μg/mL. In addition, essential oil from the leaf of M. bonii was the most active towards Bacillus cereus ATCC14579 with MIC value of 64.0 μg/mL, while M. cicatricosa showed stronger anti-candidal activity against Candida albicans ATCC 10231 with MIC value of 32.0 μg/mL. This is the first report on the chemical constituents and antimicrobial activity of the essential oils of M. cicatricosa and M. bonii. [ABSTRACT FROM AUTHOR]

The paper reports that the main constituent of essential oil from the leaves of Macclurodendron oligophlebia (Merr.) Hartl. growing in Vietnam was α-pinene (81.7%), while α-pinene (67.4%) and limonene (11.2%) were the major compounds in fruit essential oil. The composition of essential oils from the leaves and fruits of Melicope ptelefolia (Champ. ex Benth.) T.G. Hartley was characterized as germacrene D (34.0% and 31.1%, respectively), bicyclogermacrene (5.5% and 7.6%, respectively), d-elemene (9.9% and 9.0%, respectively) and α-pinene (6.5% and 9.8%, respectively). The fruit essential oil contains limonene (4.9%) and (E)-β-ocimene (8.1%). The fruit essential oils of M. oligophlebia and M. ptelefolia exhibited anti-candial activity towards Candida albicans ATCC 10231, with minimum inhibitory concentration (MIC) value of 8.0 μg/mL and 32.0 μg/mL, respectively. M. oligophlebia fruit oil also showed action against Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, and Bacillus cereus ATCC 14579, each with MIC value of 32.0 μg/mL. Also, M. oligophlebia leaf showed higher activity against Pseudomonas aeruginosa ATCC 27853 (MIC, 32.0 μg/mL). The other oil samples exhibited varying degrees of antimicrobial activity with MIC values of either 64.0 μg/mL or 128. 0 μg/mL. The leaf essential oil of M. oligophlebia displayed larvicidal activity against Aedes aegypti larvae with minimum lethal concentration (LC50) values of 16.71 μg/mL and 11.40 μg/mL, respectively at 24 h and 48 h. The fruit oil did not exhibit any larvicidal action. However, M. ptelefolia leaf and fruit showed activity at 24 h with LC50 values of 33.18 μg/mL and 35.06 μg/mL, respectively. [ABSTRACT FROM AUTHOR]

Zingiber is a genus of medicinal plants containing a rich resource of essential oils. The current study aims to describe chemical analysis and antimicrobial assay for two Zingiber species Zingiber eberhardtii Gagnep. and Z. skornickovae N.S. Lý. The rhizome oils, which were obtained by hydro-distillation using a Clevenger apparatus, were analyzed by GC-MS (gas chromatography-mass spectrometry). Extraction of Z. eberhardtii rhizome gave a yellow oil with 41 identified compounds (96.3%), in which linalool (34.9%) and 1,8-cineole (12.7%) were the principal compounds. The yellow oil of Z. skornickovae rhizome included 53 identified compounds (97.8%), with β-pinene (25.0%), (E)-caryophyllene (8.8%), and α-pinene (7.9%) as the major agents. By broth dilution method, both oils moderately controlled the growth of Gram (+) bacteria Bacillus subtilis ATCC 6633 and Staphylococcus aureus ATCC 25923 with the same MIC (minimum inhibitory concentration) value of 128 μg/mL. In particular, Z. skornickovae rhizome oil showed the best antimicrobial activity against yeast Saccharomyces cerevisiae ATCC 4098 with a MIC value of 64 μg/mL. The obtained results are promising information for future research. [ABSTRACT FROM AUTHOR]

In this study, the antimicrobial activity and constituents of essential oils from the leaves of Cinnamomum auricolor Kosterm. and C. petelotii Kosterm collected from Pù Hoạt Natural Reserve (Hạnh Dịch Commune, Quế Phong District), Vietnam were reported. The essential oils obtained by separate hydrodistillation were analyzed by means of gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC-MS). The antimicrobial activities were evaluated by microbroth dilution susceptibility assay. The main constituents of C. auricolor comprised of oxygenated sesquiterpenes mainly caryophyllene oxide (26.0%), spathulenol (11.1%), and (E)-nerolidol (10.7%). However, oxygen-containing monoterpenes were the main compounds identified in S. petelotii and they are linalool (34.3%), 1,8-cineole (20.8%) and terpinene-4-ol (9.9%). The essential oil of C. auricolor displayed prominent antimicrobial activity towards Bacillus cereus ATCC14579 and Staphylococcus aureus ATCC25923 with minimum inhibitory concentration (MIC) value of 16.0 μg/mL. In addition, the essential oil of C. auricolor also exhibited antimicrobial activity against Enterococcus faecalis ATCC29212, and anti-candidal activity towards Candida albicans ATCC10231 with MIC value of 32.0 μg/mL. The leaf essential oil of C. petelotii only exhibited activity towards S. aureus and C. albicans with MIC value of 64.0 μg/mL. The chemical constituents and antimicrobial activity of both essential oils are being reported for the first time. [ABSTRACT FROM AUTHOR]

Syzygium plants are known as sources of biologically active substances. The essential oils constituents and antimicrobial activity of Syzygium petelotii Merr. & Perry and Syzygium syzygioides (Miq.) Merr. & Perry from Vietnam are being reported. Essential oils were obtained by hydrodistillation of the leaves of S. petelotii and S. syzygioides collected from Pù Hoạt Nature Reserve, Vietnam. The constituents of the essential oils were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated by microdilution broth susceptibility assay. The results indicate that γ-guaiene (24.1%), β-caryphyllene (9.3%), α-pinene (7.8%), and β-pinene (6.1%) were the major compounds of S. petelotii. The main constituents of S. syzygioides were caryophyllene oxide (14.8%), α-pinene (10.6%), β-pinene (6.6%) and spathulenol (6.4%). The essential oil of S. petelotii showed pronounced antimicrobial activity against Pseudomonas aeruginosa ATCC27853 and Enterococcus faecalis ATCC299212, with minimum inhibitory concentration (MIC) values of 16.0 μg/mL and 64.0 μg/mL, respectively. The essential oil of S. syzygioides only displayed activity towards Pseudomonas aeruginosa ATCC27853 with MIC value of 32.0 μg/mL. Both essential oils exhibited antimicrobial activity towards Bacillus cereus ATCC14579 (MIC value, 128.0 μg/mL), and anti-candidal action against Candida albicans ATCC10231 with MIC value of 64.0 μg/mL. The chemical compositions and antimicrobial activity of essential oils of S. petelotii and S. syzygioides are being reported for the first time. [ABSTRACT FROM AUTHOR]

From hydro-distillation and GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry) analysis, chemical compositions in essential oils of two Vietnamese Piper plants Piper pendulispicum C. DC. and P. hymenophyllum Miq. were identified. Essential oils of P. pendulispicum leaf and stem are highlighted with the predominant amount of sesquiterpene hydrocarbons (73.21-78.06%), in which bicyclogermacrene (12.17-12.54%) and β-caryophyllene (12.10-14.51%) were the principal compounds. Monoterpene hydrocarbons (87.44%) are the main chemical class of P. hymenophyllum leaf oil, in which α-pinene (52.92%) and β-pinene (26.65%) are the principal compounds. These obtained essential oils with the MIC (minimum inhibitory concentration) values of 16-128 μg/mL are better than the positive control streptomycin ((MIC 128-256 μg/mL) in antimicrobial assay against three Gram-positive bacteria Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, and Bacillus cereus ATCC 14579. P. pendulispicum essential oils (MIC 16-32 μg/mL) are also comparable to the other standard cycloheximide (MIC 32 μg/mL) against the yeast Candida albicans ATCC 10231. In general, P. pendulispicum essential oil is better than P. hymenophyllum leaf oil for antimicrobial treatment. [ABSTRACT FROM AUTHOR]

Lindera chunii Merr. is an important member of the Lauraceae family of plants which are known for their medicinal values. In this research article, the chemical constituents and antimicrobial activity of essential oils from the leaves of L. chunii grown in Vietnam were reported. The essential oil was obtained by hydrodistillation of the leaves of L. chunii while the constituents were determined by using gas chromatography (GC) and gas chromatography-mass (GC/MS) spectrometry methods. The antimicrobial activity was evaluated using a microdilution broth susceptibility assay. The constituents occurring in higher amounts in the leaf essential oil of L. chunii were mainly the monoterpene hydrocarbons comprising terpinolene (13.0%), α-pinene (8.0%), β-pinene (7.6%), camphene (7.3%), β-phellandrene (7.1%) and myrcene (5.0%). The leaf essential oil of L. chunii inhibited the growth of Enterococcus faecalis ATCC29212, Staphylococcus aureus ATCC25923 and Salmonella enterica ATCC13076, each with minimum inhibitory concentration (MIC) value of 64.0 μg/mL. The corresponding median lethal concentration (IC50) values were 19.45 μg/mL, 20.45 μg/mL and 18.78 μg/mL, respectively. The essential oil also displayed anti-candidal activity towards Candida albicans ATCC10231 with MIC value of 64.0 μg/mL, and IC50 value of 23.12 μg/mL. The antimicrobial activity of L. chunii essential oil was reported for the first time as a confirmation of the traditional uses of the plant in the treatment of microbial infections. Furthermore, the paper discusses the chemotaxonomy of Lindera oil samples. [ABSTRACT FROM AUTHOR]

Essential oils from the leaves of Fokienia hodginsii (Dunn) A. Henry & H. H. Thomas and Amentotaxus argotaenia (Hance) Pilg. from Vietnam were obtained by hydrodisitllation and the chemical components determined by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS). Also the microdilution broth assay was used to test the antimicrobial activity of the essential oil. The yield of the essential oil was 0.22% (v/w). The major components of F. hodginsii were α-pinene (73.2%), limonene (10.3%), myrcene (4.1%) and β-pinene (2.6%). Amentotaxus argotaenia feature essential oil with α-pinene (20.4%), δ-cadinene (7.8%) and β-selinene (7.6%) as main compounds. The leaf essential oil of F. hodginsii displayed potent antimicrobial activity towards the Gram-positive microorganisms of Enterococcus faecalis ATCC 29212 and Bacillus cereus ATCC 14579 with minimum inhibitory concentration (MIC) values of 32.0 μg/mL and 64.0 μg/mL, respectively. The essential oil of A. argotaenia showed activity against E. faecalis ATCC 29212, Staphylococcus aureus ATCC 25923 and Bacillus cereus ATCC 14579 with MIC value of 64.0 μg/mL; as well as Pseudomonas aeruginosa ATCC 27853 (MIC, 32.0 μg/mL). Additionally, the essential oil of A. argotaenia exhibited the most anti-candidal action towards Candida albicans ATCC 10231 with MIC value of 32.0 μg/mL. The chemical constituents and antimicrobial activity of the essential oils of F. hodginsii were being reported for the first time. [ABSTRACT FROM AUTHOR]

The current study describes chemical compositions and antimicrobial activity of essential oils from the rhizome of two Vietnamese ginger plants Newmania orthostachys N.S. Lý & Škorničk. and Newmania serpens N.S. Lý & Škorničk. 49 compounds (98.4%) were identified in N. orthostachys rhizome oil, whereas 54 compounds (93.4%) were identified in N. serpens rhizome oil. N. orthostachys rhizome essential oil was dominated by monoterpene hydrocarbons (74.2%), in which β-pinene (35.7%), α-pinene (13.4%), sabinene (8.0%), camphene (6.7%), and limonene (5.1%) were characteristic compounds. Monoterpene hydrocarbons (33.5%) and sesquiterpene hydrocarbons (44.1%) represented N. serpens rhizome essential oil, as well as β-pinene (18.5%), bicyclogermacrene (12.4%), β-selinene (8.2%) were the principal compounds. In an antimicrobial assay against three tested Gram-positive bacteria Enterococcus faecalis ATCC 29212, Staphylococcus aureus ATCC 25923, and Bacillus cereus ATCC 14579, both two essential oils showed the minimum inhibitory concentration (MIC) values of 16-64 µg/mL lower than those of positive control Streptomycin (MIC 128-256 µg/ml). These two essential oils with the MIC values of 8-16 µg/mL are also better than the positive control cycloheximide (MIC 32 µg/mL) against the yeast Candida albicans ATCC 10231. [ABSTRACT FROM AUTHOR]

The present paper reports for the first time the chemical composition and antimicrobial activity of essential oil from the leaves of Phoebe macrocarpa C. Y. Wu. The yield of the essential oil was 0.28% (w/w). The essential oil features monoterpene hydrocarbons (3.3%), oxygenated monoterpenes (2.8%), sesquiterpene hydrocarbons (31.9%) and oxygenated sesquiterpenes (46.0%). The major compounds of the essential oil were β-caryophyllene (16.6%) and spathulenol (12.6%). The essential oil showed moderate antimicrobial activity towards Enterococcus faecalis ATCC299212 with minimum inhibitory concentration (MIC) value of 128 µg/mL, Staphylococcus aureus ATCC25923 (MIC 256 µg/mL) and Bacillus cereus ATCC14579 (MIC 1280 µg/mL). The essential oil did not display anti-candidal activity. [ABSTRACT FROM AUTHOR]

Essential oil from the leaves of Vitex axillariflora (Merr.) Bramley distributed in Sao La Nature Reserve - Quang Nam was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). The main chemical constituents of the essential oil were (E)-β-caryophyllene (54.3 %), α-humulene (15.6 %), bicyclogermacrene (7.9 %) and α-copaene (3.3 %). For the first time, the chemical composition of Vitex axillariflora (Merr.) Bramley was studied. [ABSTRACT FROM AUTHOR]

The compositions and antimicrobial activity of essential oils from the leaves and rhizomes of Zingiber magang N.S. Lý & Škornièk sp. nov. and Zingiber tamii N.S. Lý & Škornièk. sp. nov. from Vietnam were reported. The essential oils from Z. magang were obtained in yields of 0.12 % (leaf) and 0.18 % (rhizome), while Z. tamii afforded essential oils with yields of 0.15 % and 0.20 %, respectively, for the leaf and rhizome. The leaf essential oil of Z. magang consists of β-pinene (12.3 %) and (E)-nerolidol (10.3 %), while α-selinene (10.5 %), caryophyllene oxide (9.7 %), and neo-intermedeol (7.5 %) were found in the rhizome essential oil. However, the compositions of essential oils from the leaf and rhizome of Z. tamii comprised mainly of β-pinene (53.8 % and 55.4 %), and sabinene (12.3 % and 12.5 %), respectively. The rhizome essential oil of Z. magang displayed promising antimicrobial activity against Enterococcus faecalis ATCC 299212 and Staphylococcus aureus ATCC 25923 with the Minimum inhibitory concentration (MIC) values of 9.99 μg/mL and 9.67 μg/mL, respectively. In addition, essential oil from the leaf of Z. tamii was the most active against Escherichia coli ATCC 25922 (MIC 44.38 μg/mL) and Candida albicans ATCC 10231 (MIC, 45.62 μg/mL). This is the first report on the chemical compositions and antimicrobial activity of essential oils of Z. magang and Z. tamii. [ABSTRACT FROM AUTHOR]

Essential oils from the rhizomes of Boesenbergia quangngaiensis N.S. Lý were obtained by hydrodistillation and the chemical components were determined by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS). In addition, the microdilution broth assay was used to test the antimicrobial activity of essential oils. The yield of the B. quangngaiensis rhizome essential oils was 0.16 % (w/w). The major components identified from the rhizome essential oil of B. quangngaiensis were cis-β-elemene (18.4 %), zerumbone (11.4 %) and myrtenyl acetate (10.6 %). The antimicrobial activity test indicated that B. quangngaiensis rhizome essential oil displayed good activity against Pseudomonas aeruginosa ATCC 27853 with a Minimum inhibitory concentration (MIC) value of 7.68 μg/mL and IC50 value of 16.0 μg/mL. Also, the essential oil inhibited the growth of other tested bacteria and yeast, except Escherichia coli ATCC 25922 and Salmonella enterica ATCC 13076, with MIC value of about 30 μg/mL. The chemical components and antimicrobial activity of the B. quangngaiensis rhizome essential oil were reported for the first time. [ABSTRACT FROM AUTHOR]

In the present communication, the composition and antimicrobial activity of essential oil from the leaves of Acorus macrospadiceus (Yam.) F. N. Wei & Y. K. Li from Vietnam were reported. The yield of the essential oil was 0.25 % (w/w). The main constituents of the essential oil were β-caryophyllene (31.1 %), α-selinene (12.6 %), α-asarone (12.0 %) and α-humulene (8.0 %). The essential oil displayed anti-candidal activity against Candida albicans ATCC 10231 with a minimum inhibitory concentration (MIC) value of 8.67 μg/ mL. In addition, the essential oil exhibited a broad spectrum of antimicrobial activity against the other tested microorganisms with MIC in the range 17.33 μg/mL (Enterococcus faecalis ATCC 299212) to 100.33 μg/mL (Escherichia coli ATCC 25922). The antimicrobial activities of A. macrospadiceus are being reported for the first time. [ABSTRACT FROM AUTHOR]

This paper reports the chemical compounds and antimicrobial activity of essential oils isolated from the leaves, stem, and rhizomes of Alpinia kwangsiensis T. L. Wu and S. J. Chen (Zingiberaceae). The essential oils were separately isolated using hydrodistillation of the pulverized samples (2 kg each) materials in an all- glass Clevenger-type apparatus and characterized by GC-FID and GC/MS. The yields of the essential oils were 0.16, 0.11 %, and 0.21 % (w/w), respectively, calculated on a dry weight basis. The main constituents of the essential oils (percentages, respectively) were 1,8-cineole (16.9 %, 14.3 % and 5.8 %), terpinene-4-ol (16.0 %, 13.6 % and 14.3 %), (E)-methyl cinnamate (9.4 %, 15.4 % and 4.6 %) and β-pinene (7.6 %, 9.9.% and 3.1 %). The study found out that the rhizome essential oil was the most active against Enterococcus faecalis ATCC 299212 with a minimum inhibitory concentration (MIC) value of 1.60 μg/mL, while the leaf oil displayed pronounce activity towards Bacillus cereus ATCC 14579 (MIC 3.20 μg/mL). All the essential oils inhibited the growth of Staphylococcus aureus ATCC 25923 and Candida albicans ATCC 10231, with MIC value of 6.40 μg/mL. Therefore, the essential oils obtained from A. kwangisensis may have potential applications as antimicrobial agents. [ABSTRACT FROM AUTHOR]

Amomum velutinum X.E.Ye, Škornièk. & N.H.Xia (local name: Sa nhân lông hung) has been used in ethnomedicine for the amelioration of fever, rheumatism and microbial infections among others. In this study, the chemical constituents and antimicrobial activity of essential oils from the leaf, pseudo-stem and rhizome of A. velutinum were described. The study includes hydrodistillation of essential oils from the plant parts, instrumental analysis of the essential oils by gas chromatography (GC) and gas chromatography coupled with mass spectrometry (GC/MS) and the determination of the antimicrobial activity of the essential oils by the microdilution broth susceptibility assay. The essential oils were obtained in yields of 0.18 %, 0.11 and 0.21 % (v/w,±0.01) respectively for the leaf, pseudo-stem and rhizomes. β-Pinene (43.5 %-46.3 %) and α-pinene (5.2 %-8.1 %) were the main constituents of the essential oils. The leaf oil contained a significant quantity of myrtenyl acetate (10.5 %) and thymol (6.8 %), while β-caryophyllene (14.0 %), cis-β-elemene (9.8 %) and α-pinene (5.2 %) were found in the pseudo-stem oil in sizeable amount. The essential oils inhibited the growth of gram-positive bacteria namely Enterococcus faecalis ATCC299212 with minimum inhibitory concentration value (MIC) of 3.98-25. 56 μg/mL), Staphylococcus aureus ATCC25923 (MIC 32.87-100.56 μg/mL), Bacillus cereus ATCC14579 (MIC19. 78-20.45 μg/mL) and a strain of yeast, Candida albicans ATCC10231 (MIC 20.56-55.67 μg/mL). This was the first report on the chemical compositions and antimicrobial activity of essential oils from A. velutinum. The results are an indication of the potential of A. velutinum essential oils as a source of antimicrobial agents. [ABSTRACT FROM AUTHOR]

The rhizome essential oil of Curcuma sahuynhensis from Quang Ngãi Province, Vietnam, was obtained by hydrodistillation and analyzed by gas chromatographic techniques. The major components in the essential oil were β-pinene (52.7 %), β-caryophyllene (11.1 %), α-pinene (8.6 %), caryophyllene oxide (6.5 %), and (Z)-β-farnesene (5.9 %). The rhizome essential oil was screened for antimicrobial activity and showed good activity against the Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, and the pathogenic yeast Candida albicans with minimum inhibitory concentrations of 64 μg/mL against each of the microorganisms. This study represents the first phytochemical analysis and bioactivity screening of C. sahuynhensis. [ABSTRACT FROM AUTHOR]

This paper reports the chemical constituents and the antimicrobial activity of essential oils hydrodisitlled from the leaves of Alpinia globosa Hour (syn. Amomum globosum Lour.) and Alpinia tonkinensis Gagnep. The essential oils were analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS) techniques. The minimum inhibitory concentration (MIC) values were measured by the microdilution broth susceptibility assay. The absolute yields of the essential oils were 0.16 % (v/w, ± 0.01) and 0.21 % (v/w, ± 0.02), respectively for A. globosa and A. tonkinensis, calculated on a dry weight basis. The major constituents of A. biglobosa were β-pinene (12.1 %), α-gurjunene (10.5 %) and (Z)-13-docosenamide (9.0 %). The compounds occurring in higher amount in A. tonkinensis includes β-pinene (33.5 %), (E)-β-ocimene (9.6 %), γ-terpinene (9.2 %) and α-pinene (8.4 %). The essential oil of A. tonkinensis inhibited the growth of Saccharomyces cerevisiae (ATCC 16404) with MIC value of 25.0 μg/mL. In addition, both essential oils displayed antimicrobial activity against Escherichia coli (ATCC 25922), Staphylococcus aureus subsp. aureus (ATCC 11632) and Fusarium oxysporum (ATCC 48112) with MIC value of 50.0 μg/mL. The chemical constituents and antimicrobial activity of the studied essential oils were being reported for the first time. [ABSTRACT FROM AUTHOR]