Journal Articles - Natural Science - 2021

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Browsing Journal Articles - Natural Science - 2021 by Author "Cong-Luan Tran"
  • Publication
    Alpha-Glucosidase Inhibitory Diterpenes from Euphorbia antiquorum Growing in Vietnam
    ( 2021)
    Cong-Luan Tran
    ;
    Thi-Bich-Ngoc Dao
    ;
    Thanh-Nha Tran
    ;
    Dinh-Tri Mai
    ;
    Thi-Minh-Dinh Tran
    ;
    Nguyen-Minh-An Tran
    ;
    Van-Son Dang
    ;
    Thi-Xuyen Vo
    ;
    Thuc-Huy Duong
    ;
    Jirapast Sichaem
    Bioactive-guided phytochemical investigation of Euphorbia antiquorum L. growing in Vietnam led to the isolation of five ent-atisanes, one seco-ent-atisane, and one lathyrane (ingol-type). The structures were elucidated as ent-1α,3α,16β,17-tetrahydroxyatisane (1), ethyl ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylate (2), ent-atisane-3-oxo-16β,17-acetonide (3), ent-3α-acetoxy-16β,17-dihydroxyatisane (4), ent-16β,17-dihydroxyatisane-3-one (5), calliterpenone (6), and ingol 12-acetate (7). Their chemical structures were unambiguously determined by analysis of one-dimensional (1D) and two-dimensional (2D) nuclear magnetic resonance (NMR) and high resolution mass spectrometry, as well as by comparison with literature data. Among them, 1 is a new compound while 2 is an ethylated artifact of ent-3,4-seco-4,16β,17-trihydroxyatisane-3-carboxylic acid, a new compound. Isolates were evaluated for alpha-glucosidase inhibition. Compound 3 showed the most significant inhibitory activity against alpha-glucosidase with an IC50 value of 69.62 µM. Further study on mechanism underlying yeast alpha-glucosidase inhibition indicated that 3 could retard the enzyme function by noncompetitive.
  • Publication
    Two new cycloartanes from the leaves of Combretum quadrangulare growing in Vietnam and their biological activities
    ( 2021)
    Huu-Hung Nguyen
    ;
    Thi-Phuong Nguyen
    ;
    Nguyen Tien Trung
    ;
    Cam-Tu D. Phan
    ;
    Thi-Bich-Ngoc Dao
    ;
    Dinh-Tri Mai
    ;
    Jirapast Sichaem
    ;
    Ngoc-Hong Nguyen
    ;
    Cong-Luan Tran
    ;
    Thuc-Huy Duong
    Two novel cycloartanes, combretanones G and H (1 and 2), were isolated from the leaves of Combretum quadrangulare. Their structures were elucidated by applying a set of spectroscopic methods, while their relative configurations were determined using DFT-NMR chemical shift calculations and subsequent assignment of DP4 probabilities. Compounds 1 and 2 are C-23/C-24 stereoisomers of the previously-reported euphonerin E. Both exhibited moderate cytotoxicity against three human cancer cell lines. Compound 2 was shown to be a potent antiparasitic. Our results confirm the traditional medicinal uses of Combretum quadrangulare in Vietnam.