Euphorbia tirucalli has not been chemically studied much in Vietnam. This research described the isolation and elucidation of compounds isolated from the plant collected in Binh Thuan. Multiple chromatographic methods were applied, including normal phase silica gel column chromatography and thin-layer chromatography. Seven compounds were isolated and their chemical structures were elucidated by spectroscopic analysis as well as comparing their data with the ones in the literature. They are arjunolic acid (1), eriodictyol (2), quercitrin (3), afzelin (4), scopoletin (5), 3,3′,4- trimethylellagic acid (6), and gallic acid (7). Among them, compound 1 a major component was isolated for the first time in Euphorbia genus, while three compounds 2, 4, and 5 were isolated from this species for the first time.

The lichen Roccella sinensis has not been studied chemically. This research described the isolation and elucidation of compounds isolated from the lichen Roccella sinensis collected in Binh Thuan. Phytochemistry investigation of this lichen was carried out by using normal phase silica gel column chromatography and thin-layer chromatography. Six compounds was isolated. Their structures were established by extensively spectroscopic analysis as well as comparison with NMR data in the literatures. They are (+)-D-montagnetol (1), (+)-D-erythrin (2), lecanorin (3), 1-acetylerythritol (4), (E)-nostodione A (5), and 2,4-dihydroxyphthalide (6). This is the first time compounds 3 6 were found in the Roccella genus. Compounds 1, 2, and 6 were evaluated for their cytotoxic activities against HepG2 (liver hepatocellular carcinoma), NCI-H460 (human lung cancer), MCF-7 (human breast cancer), and HeLa (human epithelial cancer) and all of them showed no activity.

From the methanol extract of the root of Streptocaulon juventas Merr, three cardenolide derivatives were isolated. Their strutures were determined by spectroscopic methods. This is the first time that (17α)-H-periplogenin-3-O-β-D-glucopyranosyl-(1–4)-2-O-acetyl-3-O-methyl-β- fucopyranoside (1) and periplogenin-3-O-β-cymaropyranosyl-(1®4)--glucopyranoside (2) were isolated from the root of S. juventas together with the known 17α-H-periplogenin-3-O-β- digitoxopyranosyl-(1®4)-O-β-glucopyranosyl-(1®6)-O-β-glucopyranoside (3).

The genus Phyllanthus (Phyllanthaceae) includes more than 900 plant species found in tropical and subtropical regions. Many of these species are widely used in folk medicine. The leaves, roots, and stem bark of Phyllanthus acidus (L.) Skeels have been used in Vietnamese folk medicine as an antibacterial, antiviral, analgesic, anti-inflammatory, neuroprotective, hepatoprotective, antifibrotic. From the ethanol extract of the roots of Phyllanthus acidus (L.) Skeels growing in Binh Thuan province, six compounds phyllanthol (1), glochidone (2), lupeol (3), glochidonol (4), 􀀱-lupene (5), and spruceanol (6) were isolated. Their structures were established by extensive spectroscopic analysis as well as comparison with NMR data in the literatures. This is the first time that compounds 4-6 were found in Phyllanthus acidus (L.) Skeels.

Three cardenolides were isolated from the root of Streptocaulon juventas Merr. Their strutures were elucidated by their spectral data. A new cardenolide derivative named acovenosigenin A 3-O-glucosid from the metanol extract of the root of Streptocaulon juventas Merr.