Different levels of exploring the antioxidant and antitumor potential of Salvia officinalis and Salvia rosmarinus

Abstract

Salvia officinalis (sage) and Salvia rosmarinus (previously Rosmarinus officinalis, rosemary) are commonly used medicinal plants from the Lamiaceae family, with strong antioxidant abilities. This study was carried out in several stages to comprehensively and gradually explore the antioxidant and antitumor mechanisms of their ethanolic extracts using different experimental approaches. Their in vitro antioxidant activity was assessed using ABTS assay. Plasmid pUC19 E. coli XL1-Blue was used to evaluate their genoprotective activity, while SOS/umuC assay on Salmonella typhimurium TA1535/pSK1002 and Comet assay on human lung fibroblast cell line (MRC-5) were employed to examine their antigenotoxic potential. Furthermore, their antitumor mechanisms were analyzed on the colorectal cancer cell line (HCT-116) by testing their impact on the cells’ viability (MTT assay), as well as the production of reactive oxygen species (ROS) (NBT test) and nitric oxide (NO) (Griess assay). The results showed that sage extract had slightly higher ABTS-scavenging and antigenotoxic activities in the bacterial model when compared to the rosemary extract, however, opposite results were obtained for the acellular model. Moreover, both extracts protected the MRC-5 cells from the induced genomic damages. As for tumor cells, sage extract reduced their viability by approximately 10 %. Additionally, both extracts significantly reduced the ROS production, while also increasing the NO production, especially the rosemary extract. These results delivered novel information about the nature of antioxidant effects of sage and rosemary ethanolic extracts. They provided substantial protection of the acellular, bacterial and healthy human cellular models by employing radical-scavenging and antigenotoxic mechanisms. At the same time, both extracts exhibited antitumor activity towards colorectal cancer cells in vitro that could be mediated by inducing an increase in NO production. With that being said, sage and rosemary ethanolic extracts represent potent genoprotective, antioxidant and antitumor agents. However, their exact mechanisms of action remain to be further explored and clarified