Structure Elucidation, Antimicrobial and Cytotoxic Activities of a Halimane Isolated from Vellozia kolbekii Alves (Velloziaceae).

A new halimane diterpene was isolated from Vellozia kolbekii Alves (Velloziaceae) and identified as (5R,8R,9S,13R)-halim-1,10-ene-15,16-diol (1). It showed cytotoxicity against three human cancer cell lines, SF-295 (glioblastoma), MDA-MB-435 (melanoma), and HCT-8 (colon adenocarcinoma). In the mechanism of cytotoxic action, halimane 1 interferes in two major phases of the cell cycle: in S phase, in which DNA synthesis occurs and where it is very sensitive to damage, and G2M phase which is the phase of preparation for mitosis and mitosis itself, showing apoptosis-inducing properties. Antimicrobial activity towards Gram-positive and Gram-negative bacteria was studied and, against Bacillus cereus, B. subtilis, Escherichia coli, and Pseudomonas aeruginosa, a MIC value of 0.025 μM was observed for halimane 1, which is more active than the positive control chloramphenicol.