No abstract

Homalomena cochinchinensis Engl. is a rare species which is found in Southern China, Cambodia, Laos and Vietnam and its chemical constituents and bioactivity have not been determined yet. In this study, we identified 32 and 38 compounds in acetone extracts of H. cochinchinensis aerial part and rhizome, respectively via gas chromatography mass spectrometry (GC/MS). The main constituents of acetone extract of the aerial part were 3-((4Z,7Z)-Heptadeca-4,7-dien-1-yl)phenol (18.73%); cis-9,cis-12-Octadecadienoic acid (12.04%); linolenic acid (11.08%); n-Hexadecanoic acid (10.13%); (Z)-3-(Heptadec-10-en-1-yl)phenol (7.09%); ?-Sitosterol (5.58%) and linalool (5.56%). On the other hand, acetone extract of rhizome contained linalool (28.42%); 1,2,3-Propanetriol, 1-acetate (10.13%); 3-((4Z,7Z)-Heptadeca-4,7-dien-1-yl)phenol (5.28%); 3-Buten-2-one, 3-methyl-4-(1,3,3-trimethyl-7-oxabicyclo[4.1.0]heptan-1-yl)- (5.28%) and 4-(2,6,6-Trimethyl-cyclohex-1-enyl)-butyric acid (4.54%). Furthermore, this study has also proved the antibacterial activity of acetone extracts from the aerial part and the rhizome of this species for the first time using disk diffusion method. The results showed that the extract of the aerial part could inhibit the growth of 5 out of a total 6 bacterial strains, including Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis and Staphylococcus aureus; while the susceptible strains to the rhizome extract were 5 strains, such as B. cereus, E. coli, P. aeruginosa, Salmonella typhimurium and S. aureus. The findings suggest the further application of this species in pharmacology and medicine.

Habenaria diphylla (Nimmo) Dalzell is reported for the first time as a new discovery for the flora of Vietnam based on the specimens collected in Binh Chau-Phuoc Buu Nature Reserve, Ba Ria-Vung Tau Province. The present study provided the detailed characteristics of the species including detailed photographs of the morphological characteristics, the cross section of the leaf, inflorescence axis and root. Furthermore, the information about the species, including distribution, habitat, ecology and conservation status were also provided.

The objective of this work was to analyze the content and the chemical diversity of the essential oils from the aerial parts of eight species belonging to Zingiberaceae family collected in Binh Chau-Phuoc Buu Nature Reserve, Vietnam. The essential oils were isolated by hydrodistillation and their constituents were investigated by gas chromatography-mass spectrometry. The essential oils from the aerial parts of eight studied species, including Zingiber zerumbet, Zingiber pellitum, Curcuma pierreana, Globba macrocarpa, Globba globulifera, Alpinia conchigera, Stahlianthus campanulatus and Amomum sp. were obtained in a yield of 0.01%, 0.008%, 0.01%, 0.012%, 0.012%, 0.02%, 0.015 and 0.3%, respectively. There were a total of 75 compounds identified from the essential oils obtained from eight studied species. Four main clusters and three subclusters were formed by the cluster analysis. Cluster I consisted of A. conchigera with the presence of β-elemene (51.76%) and caryophyllene (28.1%). Cluster II contained five species, including Z.

Homalomena vietnamensis is a rare species of the Homalomena genus and only found in Middle region of Vietnam. In this study, we found 10 compounds in ethanol extracts of leaf and rhizome of H. vietnamensis, such as cadinane-4β,5α,10α-triol, oplopanone, 4-epi-oplopananol, 2α-hydroxy homalomenol A, 1β,4β,7β-Trihydroxyeudesmane, homalomentetraol, 4-acetoxyoplopananol, 5,7-diepi-2a-acetoxyoplopanone, eudesma 4β, 7α- diol-1β-fumarate), and homalomenol F, via liquid chromatography-mass spectrometry (LC/MS). Moreover, the antibacterial activity of ethanol extracts of leaf and rhizome from this species has been evaluated by disc diffusion method for the first time. The results showed that rhizome extract of could inhibit the growth of 5 tested micro-organisms, including of Bacillus cereus (28.3 ± 1.5 mm), Salmonella enteritidis (19.5 ± 1.5 mm), Staphylococcus aureus (16.3 ± 1.5 mm), Escherichia coli (14.7 ± 1.2 mm), and Pseudomonas aeruginosa (8.2 ± 0.8 mm), while the leaf extract showed antibacterial effect against Bacillus cereus (22.0 ± 2.0 mm), S. enteritidis (14.7 ± 0.6 mm), and S. aureus (12.5 ± 1.8 mm).