A COMPARATIVE ANALYSIS OF THE CHEMICAL COMPOSITION AND BIOACTIVITY OF THREE MEDICINAL PLANTS IN THE RUBIACEAE FAMILY: Cubanola domingensis, Morinda citrifolia, AND Morinda royoc
R. BUSSEY, E. JOVEL, J. SALAZAR, A. VELOZ, E. RODRIGUEZ

Due to the purported efficacy of traditional medicines prepared from Morinda citrifolia, Morinda royoc, and Cubanola domingensis, these three plants of the Rubiaceae family were collected in La Altagracia, Dominican Republic during June 2001. Medicinal uses of C. domingensis are unknown but the fruit, leaves, and roots of both Morinda species are used for a wide variety of ailments including cancer and impotence. These closely related species were tested for bioactivity and the chemical composition of active extracts was further analyzed with thin-layer chromatography (TLC). Fresh plant material was extracted in 95% ethanol and tested in disk diffusion assays against the gram-positive bacteria Bacillus subtilis, Bacillus cereus, and Staphylococcus aureus, the gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, and three strains of the fungus Candida albicans. M. royoc and M. citrifolia roots were the only extracts that produced consistent growth inhibition in B. cereus, B. subtilis, P. aeruginosa, S. aureus, and all strains of Candida albicans. The compounds in this extract were also phototoxic when treated with long-wave ultraviolet light. As expected from plants in the same genus, the Morinda plants showed similar chemical composition when analyzed with TLC. A preliminary cytotoxicity screening using the brine shrimp assay proved inconclusive. Further chemical analysis is necessary to isolate the active compounds.