Two new acetophenone derivatives named knepachycarpanone A (1) and knepachycarpanone B (2) together with a new cardanol derivative named knepachycarpanol C (3) were isolated from the EtOAc extract of Knema pachycarpa stems. Their chemical structures were established on the basis of spectral evidences. Compounds 1 and 2 exhibited moderate cytotoxicity against Hela cancer cell line with IC50 values of 26.92 ± 1.46 and 30.20 ± 1.97 μM, respectively.
Knema is a genus of tropical evergreen trees of the family Myristicaceae found in South East Asian countries such as Vietnam, Thailand, and Malaysia. In this paper, four lignans, (+)-pinoresinol (1),(+) epi-pinoresinol (2), piperitol (3), and pluviatilol (4), were isolated from the ethyl acetate extract of the fruit of Knema pachycarpa, an indigenus tree in Vietnam. The chemical structures were determined by spectroscopic data and comparison with the reported literature. These compounds were isolated from Knema genus for the first time.
Asystasia gangetica (L.) T. Anderson is an edible vegetable, cultivated in Vietnam. This plant was reported to contain a diverse chemical composition including megastimans, flavonoids, iridoids, and phenylpropanoid glycosides. It also exhibited many interesting biological activities such as antibacterial, antifungal, antihypertensive, anti-asthmatic, analgesic, anti-inflammatory, tyrosinase inhibitory, antioxidant, and antidiabetic effects. However, so far, the studies on this species in Vietnam are relatively few. In this study, six compounds including lutein (1), verbascoside (2), indole-3-carboxylic acid (3), 3α,24-dihydroxy-olean-12-en-28-oic acid (4), ursolic acid (5), and pomolic acid (6) were isolated from the ethyl acetate fraction of the aerial parts of A. gangetica. Their structures were identified based on the NMR and MS spectroscopic data and comparison with those in the literature. Four compounds (3-6) have been isolated from this plant for the first time.
Chromatographic separation of ethyl acetate extract of the stingless bee Lisotrigona furva propolis, that collected in Khanh Hoa province, led to isolation of five cycloartane‐type triterpenes including cycloartenone (1), cycloartenol (2), (24E)‐3β‐hydroxycycloart‐24‐en‐26‐al (3), mangiferonic acid (4) and mangiferolic acid (5). Mango plant (Mangifera indica) was suggested to be a resin source of the propolis. The propolis EtOH extract showed good antimicrobial activity on Gram (+) strain E. feacalis and fungus C. albicans. Among the isolated compounds, compound 3 displayed selective activity against three Gram (+) strains and C. albicans over Gram (‐) strains with all MIC values of 64 μg/mL. However, the propolis EtOH extract was not active against LU‐1 and MCF‐7 cancer cell lines. Only compound 5 exhibited moderate activity on LU‐1 cancer cell line with IC50 of 13.33 μg/mL.
The genus Macaranga, one of the largest genera of the Euphorbiaceae family has approximately 300 species distributed in the tropical regions. Plants of this genus displayed various bioactivities such as antioxidant, antitumor and antimicrobial effects. Macaranga balansae Gagnep. is an endemic plant in Vietnam, that ethyl acetate extract showed cytotoxicity to cancer cell line. In this article, we report the isolation and structural elucidation of six known compounds from the ethyl acetate extract including (‐)‐dehydroxycubebin (1), trans‐coniferyl aldehyde (2), 3,3',4'‐tri‐O‐methyl ellagic acid (3), stigmastane 3β,5α,6β‐triol (4), 2,3‐dihydroxy‐1‐(4’‐hydroxy‐3’‐methoxyphenyl) propan‐1‐one (5), and protocatechuic acid (6). To the best of our knowledge, compounds 1‐5 were isolated from Macaranga genus for the first time.
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