Plectranthus spp. is widely known for its medicinal properties and bioactive metabolites.The cytotoxic and genotoxic properties of the four known abietane diterpenoids: 7α-Acetoxy-6β-hydroxyroyleanone (Roy), 6,7-dehydroroyleanone (Deroy), 7β,6β-dihydroxyroyleanone6 (Diroy),and Parvifloron D (Parv), isolated from P. madagascariensis (Roy, DeRoy, and Diroy) and P. ecklonii(Parv) were evaluated. The tested compounds showed cytotoxic effects against the human leukemiacell line CCRF-CEM and the lung adenocarcinoma cell line A549. All tested compounds inducedapoptosis by altering the level of pro- and anti-apoptotic genes. The results show that from the testedditerpenoids, Roy and Parv demonstrated the strongest activity in both human cancer cell lines,changing the permeability mitochondrial membrane potential and reactive oxygen species (ROS)levels, and possibly inducing mtDNA or nDNA damage. In conclusion, the abietane diterpenoidstested may be used in the future as potential natural chemotherapeutic agents.
Keywords: DNA damage; Plectranthus sp.; ROS levels; apoptosis; cytotoxic activity; gene expression; mitochondrial membrane potential.