Using bioactivity-directed isolation procedures, three new spirostanol saponins designated sansevierin A (1), sansevistatin 1 (2), and sansevistatin 2 (3) were isolated (10(-5) % yield) from the CH3OH-CH2Cl2 extract of Sansevieria ehrenbergii, accompanied by three known steroidal saponins (4-6). The structures were determined on the basis of chemical methods and spectroscopic analysis, especially 1D and 2D NMR experiments. Each of the saponins was evaluated against the P388 lymphocytic leukemia cell line and a panel of human cancer cell lines. Except for 1, all were found to cause inhibition of cancer cell growth. In addition, most of the saponins exhibited antimicrobial activity, particularly against the pathogenic fungi Candida albicans and Cryptococcus neoformans.

A bioassay-guided investigation of Gustavia hexapetala led to the isolation of a new cancer cell growth inhibitor designated gustastatin (1) and four previously known cancer cell growth inhibitors that included betulinic acid (2). The structures were assigned on the basis of analyses of HRMS combined with 1D and 2D NMR data. The structure of portentol (5) was confirmed by an X-ray crystal structure determination.

The water-soluble crude extract prepared from Imperata cylindrica (Beauv.) was investigated for its immunomodulating activity. A set of polysaccharides with high molecular weights has been isolated by fractionation using gel filtration and anion-exchange chromatography. Each step of purification was monitored by bioassays. The presence of six monosaccharides has been established by chemical analysis. Quantitative analysis showed that the ratio of these monosaccharides differed from one polysaccharide to another. The crude extract as well as some of the purified polysaccharides enhance the proliferation of murine splenocytes.