• Korean Journal of Plant Taxonomy
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• v.46 no.2
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• pp.163-174
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• 2016

Gnetum (Gnetaceae, Gnetales) is a gymnosperm genus with ca. 35 species distributed in tropical forests around the world. Due to its dioecious habit and lack of diagnostic characters from vegetative tissue, the identification of Gnetum species is not easy without seeds or reproductive structures. To identify and verify their phylogenetic positions, we applied DNA barcoding to Cambodian Gnetum collections gathered between 2010 and 2015, with previously designed cp matK gene primers. We newly sequenced partial matK sequences from 72 Gnetum collections, 43 out of 72 from Cambodia, and analyzed 115 Gnetum accessions using the neighbor-joining method. The resulting neighbor-joining tree categorized Cambodian Gnetum samples into three clades of species: G. macrostachyum, G. montanum, and G. aff. gracilipes. The recognition of G. aff. gracilipes in Cambodia is reported here for the first time. Taxonomic information for the three recognized Cambodian Gnetum species is provided and the benefits of the taxonomic reevaluation assisted by DNA barcoding are emphasized in this work.

• Natural Product Sciences
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• v.12 no.1
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• pp.29-37
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• 2006

One hundred and twenty six Vietnamese traditional herbals belonging to 59 families were screened for their free radical (DPPH) scavenging activity and inhibitory effect on lipid peroxidation. Of these, MeOH extracts of seven plants, including Euphorbia thymifolia (leaf), Gnetum montanum (stem), Heterosmilax erythrantha (root), Morus alba (leaf), Syzygium formosum (leaf), Jussiaea repens (aerial parts), and Camellia sinensis (leaf), exhibited significant antioxidant activities. All of these herbs showed remarkable free radical scavenging activities with $IC_{50}$ values of 11.0, 14.5, 17.0, 13.6, 10.8, 7.7, and $8.5\;{\mu}g/ml$, respectively, and significant inhibitory effects on lipid peroxidation with 79.7, 83.8, 78.9, 82.5, 88.8, 88.0, and 96.2% inhibitions, respectively, at the concentration of $50\;{\mu}g/ml$.