RESUMO
CONTEXT: Medicinal plants are continuously screened for their pharmacological properties. Despite the diversity and the numerous phytochemicals found in Ardisia (Myrsinaceae) species, its full biological potential has not been fully explored. OBJECTIVE: Four naturally occurring alkylbenzoquinone derivatives, namely ardisiaquinone N (1), ardisiaquinone J (2), ardisiaquinone K (3) and a mixture of ardisiaquinone P (4) and K (3) from Ardisia kivuensis Taton (Myrsinaceae) were investigated in vitro for their cytotoxicity and antimicrobial activity. MATERIALS AND METHODS: Minimal inhibitory concentration (MIC) was determined using the broth micro-dilution assay. Tumor cells growth inhibition was performed by sulphorhodamine B (SRB) assay while sub-diploid DNA fraction was measured by flow cytometry. RESULTS: Compounds 1, 2 and 3 showed significant antimicrobial activity against two Gram-positive bacteria and one fungus (with MICs varying between 3.12 and 6.25 µg/ml). The four compounds exhibited remarkable antiproliferative activity against the leukemia cell line TPH-1 with IC50 inhibition values between 2 and 2.1 µg/ml. Cytotoxic activity was found to be related to apoptosis induction. DISCUSSION AND CONCLUSION: These findings suggest that natural compounds herein studied are interesting potential candidates for the development of new therapeutic agents, especially against leukemia and Gram-positive bacterial infections.