Phytochemical Investigation of the Gnetum formosum in Vietnam

Four compounds, including a new steroidal saponin 12‐ O ‐cinnamoyl‐20‐ O ‐benzoylsarcotin‐3‐ O ‐ β ‐ d ‐thevetopyranosyl‐(1→4)‐ β ‐ d ‐oleandropyranosyl‐(1→4)‐ β ‐ d ‐cymaropyranosyl‐(1→4)‐ β ‐ d ‐cymaropyranoside ( 1 ) and three known as stemucronatoside G ( 2 ), syringaresinol ( 3 ), and 4‐hydroxybenzoic acid ( 4 ) were isolated from the aerial parts of the Gnetum formosum Markgr. by using multiple chromatography techniques. Their chemical structures were determined by modern spectroscopic techniques such as 1D, 2D‐NMR, and HR‐ESI‐MS. These compounds were screened and tested for cytotoxic activity against human hepatocarcinoma cells, human lung carcinoma cells (SK‐LU‐1), and human chronic leukemia cells (K562) with IC 50 values ranging from 3.03–5.90 µg/mL. They were also examined for nitric oxide production inhibition on RAW 264.7 cells, only compound 3 exhibited the anti‐inflammatory activity with the IC 50 value 94.79±2.46 µg/mL. Interestingly, our project is the first phytochemical and biological investigation of G. formosum . This is the first time that compound 2 was announced from the family Gnetaceae.