Plants from the Plectranthus genus are commonly known for their medicinal properties, and their applications are vast in traditional medicine [1,2]. Often accountable for these properties, bioactive secondary metabolites such as diterpenes are present in these plants, and some are cytotoxic.
The abietane diterpenoids obtained from Plectranthus plants, 7α-acetoxy-6β-hydroxyroyleanone, 7β,6β-dihydroxyroyleanone, 6,7-dehydroroyleanone, and Parvifloron D are examples of this class of bioactive diterpenes [3,4].
According with the previous studies, this work aimed to further evaluate the cytotoxic activity of these abietanes. This property was evaluated through MTT assays on A549 cells and CCRF-CEM cells. In addition, the level of intracellular Reactive Oxygen Species (ROS) in these cells was also measured. Our study has revealed that on CCRF-CEM cells, there is a slight increase of the ROS levels after exposure to all compounds. Nevertheless, on A549 cells the levels of ROS increase approximately 10-fold, with notorious increase after exposure to 7β,6β-dihydroxyroyleanone, which can induce cytotoxicity due to ROS accumulation on cells. In conclusion, this study proves the therapeutic potential of Plectranthus-derived diterpenes and validates its use in traditional medicine.
[1] Rijo P., et al. Magn Reson Chem MRC. 2005;43(7):595–8.
[2] Rijo P., et al. Biochem Syst Ecol. 2007 Apr;35(4):215–21.
[3] Burmistrova O., et al. J Nat Prod. 2013;76(8):1413–23.
[4] Gaspar-Marques C., et al. Phytomed. 2006;13(4)3:267-271