Randia siamensis

Key word index -- Cardioveiscular activity, pseudoginsenoside-RTi, Randia siamensis, saponins, uterine contractility, ichthyotoxic activity. 

Accordingly, a number of components have been isolated from the fhiit of Randia siamensis and their structures established. A preliminary study found that an alcohol extract of the fruit of R. siamensis caused a significant uterine contraction in vivo. Thus the major component isolated in this study was examined for its in vivo activity on blood pressure, heart rates and spontaneous uterine contractility. 

The ethanol extract from the fruit of Randia siamensis after separation by column chromatography yielded four components ursolic acid (1), pseudoginsenoside-RPi (2), pseudoginsenoside-RTi (3) and siamenoside (4). 1 is a conunonly occurring triterpenoid acid while 2 and 3 are saponins which were first isolated from Panax (Araliaceae) species and were identified by Tanaka et al. (198S). The major component isolated in our study, oleanolic acid glycoside 3, has since been reported to be present in additional species (Morita et al., 1986 Shukla and Thakur, 1988 Shukla, 1989 Ida et al., 1994 Sakai et al., 1994). In the structural elucidation of the four components from R. siamensis, NMR spectroscopy was foimd to be... 

Plant material The fruit of Randia siamensis was collected from Nakompathom Province, Thailand, in July, 1984. Authentication was achieved by comparison with herbarium specimens in the Botany Section, Technical Division, Department of Agriculture, Ministry of Agriculture and Cooperative, Thailand. A voucher specimen of plant material has been deposited in the herbarium of the Faculty of Pharmaceutical Sciences, Chulalongkom University. 

Chemical studies of numy other species of Randia have shown the presence of triterpenoid acids such as oleanolic add and randialic add. Previous work on the roots of R. siamensis yielded mesembryanthemoidigenic acid, 3-P-acetyloleanolic add, ursolic acid and 3-0-(a-L-arabinosyl)-oleanolic add (Lapikanom et al., 1983 Woo et al., 1984). However, there have been no previous reports of compounds isolated from the fhiit of this plant. 

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