Placolobium vietnamense N.D.Khoi & Yakovlev (Fabaceae) is an indigenous plant of Vietnam. Up to now, this plant has not yet been chemically and biologically studied. In this paper, six isoflavones including afrormosin (1), cladrastin (2), 8‐O‐methylretusin (3), millesianin C (4), barbigerone (5), and durallone (6) were isolated from the ethyl acetate extract of the stem bark of Placolobium vietnamense. Their structures were established by means of physical data (ESI MS, 1D and 2D NMR) and evaluated for the cytotoxic activities against liver hepatocellular carcinoma (HepG2), human lung cancer (NCI‐H460), human epithelial carcinoma (HeLa) and human breast cancer (MCF‐7) cell lines. This is the first report on phytochemical studies of this plant.

Seven compounds, including two diglycoside flavonoids hesperidin (1) and rutin (2), one phenolic acid (E)-ferulic acid (3), two amino acids namely tyrosine (4) and arginine (5) and two sterols comprising spinasterol (6) and spinasterol 3-O-β-D-glucopyranoside (7) were isolated from the whole plant of Amaranthus spinosus L., Amaranthaceae collected at Bu Dang district, Binh Phuoc province, Vietnam. Their chemical structures were elucidated by spectroscopic methods including ESI-MS, 1D and 2D-NMR and compared with published data. All these compounds were known to be presented for the first time in this plant. Among them, three compounds 1, 6 and 7 were isolated from Amaranthus genus for the first time.

Lunularin (1), marchantin A (2), isoriccardin C (3), luteolin (4) and apigenin (5) were isolated from the ethyl acetate extract of Marchantia polymorpha collected at Lam Dong province, Vietnam. The chemical structures of these compounds were elucidated by HR‐MS and NMR spectroscopic analysis as well as compared with data in the literature. The evaluation of the cytotoxic activity against MCF‐7, Hep G2, NCI‐H460, and HeLa cancer cell lines of the ethyl acetate extract and compounds (1) and (3) showed that (1) was potent against MCF‐7 cancer cell with the IC50 value of 4.59±0.38 μg/mL. The evaluation of DPPH radical scavenging activity displayed strong activities of the ethyl acetate extract, compounds (1) and (3) with SC50 of 12.75±13.27, 3.99±0.47 and 12.81±0.43 μg/mL, respectively, while SC50 of the positive control Trolox was 7.34±0.87 μg/mL. The antibacterial evaluation on the ethyl acetate extract and two compounds (2) and (3) against Staphylococcus epidermidis showed that (3) possessed remarkably antibacterial activity with the inhibition zone of 12.67 mm at a concentration of 50 μg/well.

From the ethyl acetate extract of the stem bark of Phyllanthus emblica, a mixture of triterpene glycosides (1) and six compounds (2‐7) were isolated. The structure of these compounds were established as 3‐O‐α‐L‐arabinopyranosyloleanolic acid (1a), 3‐O‐α‐L‐arabinopyranosylursolic acid (1b), 16‐dehydropregnenolone (2), periplogenin (3), betulin (4), phyllanthol (5), gallic acid (6) and methyl gallate (7) by 1D, 2D NMR spectroscopies, and high resolution ESI‐MS analysis, as well as comparison with those reported in the literature. The compounds (1a), (1b), (2) and (3) were found for the first time from this genus.

In the investigation of the chemical constituents of the ethyl acetate extract of Passiflora incarnata Linn., collected at Dong Hoa district, Phu Yen province, six compounds were isolated. They were one megastigmane, dehydrovomifoliol (1), three megastigmane monoglycosides, roseoside (2), byzantionoside B (3) and foliasalacioside L (4), one flavone Cmonoglycoside vitexin (5) and one nucleotide glycoside uridine (6). Their chemical structures were elucidated by means of HR-MS, 1D and 2D-NMR data analysis and the comparison their NMR data with those reported in the literature. Although, these compounds had already reported in the other species, they were known in Passiflora incarnata Linn. for the first time to the best of our knowledge.