PRELIMINARY BIOACTIVITY STUDIES OF THREE MEDICINAL PLANTS OF THE DOMINICAN REPUBLIC
J. A. MENDOZA, A. VELOZ, E. RODRIGUEZ

Medicinal plants are widely used throughout Latin America. In this study, three plants used in folk medicine were collected in the Dominican Republic and tested for bioactivity. Macfadyena unguis-cati (Bignoniaceae) and Guazuma ulmifolia (Sterculiaceae), have been used to alleviate gastrointestinal pains while Senna occidentalis (Fabaceae) is used as a “humoral cleanser.” In addition, Senna sp. has recently been studied for its anti-cancer properties and its toxicity to cattle. Various plant parts of these three species were extracted in 95% ethanol and tested in several anti-microbial disk diffusion bioassays against the gram-positive bacteria Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus, the gram-negative bacteria, Pseudomonas aeruginosa and Escherichia coli, and three strains of the fungus Candida albicans. The assays were also conducted after exposing the extracts to both long and short UV light to test for photoactivity. A brine shrimp assay was used to test for cytotoxicity. The root and seedpod extracts of S. occidentalis and the root extract of M. unguis-cati showed some bioactivity, while all other extracts were inactive. The brine shrimp assays showed that all extracts except the S. occidentalis leaf extract were cytotoxic to some extent. The cytotoxicity and anti-microbial activity of S. occidentalis root, as well as its previously studied anti-cancer properties, make this plant a good candidate for further study.