Thesis (M.Sc. in Pharm.)--Chulalongkorn University, 2013

During the course of our screening of medicinal plants for anti-Herpes simplex virus (HSV) activity, an ethyl acetate extract and a methanol extract prepared from the stem bark of Mallotus plicatus (Müll.Arg.) Airy Shaw showed significant anti-HSV potential. A chemical investigation was then conducted using several chromatographic techniques. This led to the isolation of nine compounds. The structure determinations of the isolated compounds were carried out using a combination of spectroscopic techniques (UV, IR, MS and NMR). Two of the isolates were structurally characterized as new compounds and named bergenin-8-O-α-L-rhamnoside and seco-bergenin-8-O-α-L-rhamnoside. The other seven compounds were identified as bergenin, daucosterol, protocatechuic acid, 11-O-acetylbergenin, scopoletin and blumenol A. The results from the anti-HSV activity assay showed that bergenin-8-O-α-L-rhamnoside and protocatechuic acid were weakly active against HSV. Some of the isolated compounds were also evaluated for cytotoxicity against KB cells and scavenging activity against DPPH free radicals, but none of them showed the activities.