Objective: There is an increasing interest in the use of natural products to oppose human diseases. The leaves of Flacourtia rukam Zoll and A. Mortizi, Archontophoenix alexandrae (Wendl. and Drude), and Dictyosperma album (Bory) H. Wendl. and Drude ex. Scheff were selected for phytochemical and biological screening to search for new natural drugs. Total ethanolic extracts of the mentioned plants were subjected to preliminary phytochemical screening followed by screening their cytotoxic, antimalarial, antimicrobial, and anti-inflammatory activities. Materials and Methods: The extracts were tested for the presence of various phytochemicals. The cytotoxic activity was determined against five human cancer cell lines: melanoma, breast, oral, ovarian, and cervical cancers and two noncancerous cell lines. The antimalarial activity was determined against chloroquine-sensitive (D6) and chloroquine-resistant (W2) strains of Plasmodium falciparum depending on the plasmodial lactate dehydrogenase activity. Antimicrobial screening was continued using the modified version of the CLSI method whereas anti-inflammatory activity was determined by measuring the activity of inducible nitric oxide synthase (iNOS). Results: Preliminary phytochemical screening indicated the absence of alkaloids, anthraquinones, and saponins in all the extracts. The latter showed no toxicity against the tested cancer cell lines and no activity against the tested microbes. The extract of D. album lacks the activity against D6 and showed a moderate activity against W2 P. falciparum (IC50= 41.7 μ/mL). D. album extract showed no inhibition for iNOS as contrary to F. rukam and A. alexandrae extracts which showed a good inhibition (IC50= 20 and 100 μ/mL, respectively). Conclusion: All tested extracts lack cytotoxic and antimicrobial activities.
Key words: Antimicrobial, Archontophoenix, cytotoxic, Dictyosperma, Flacourtia, inducible nitric oxide synthase