Baccharis trimera (BT) and Bacharis dracunculfolia (BD), two species occurring in tropical areas of South America, are widely used in folk medicine as digestive aid, anti-inflammatory and anti-diabetic agents. This study aims the comparison between these two species regarding their cytoprotective effects against the insults t-BHP (0,5 mM) and paraquat (1 mM), using two cell lines: human hepatocellular carcinoma (HepG2) and the mouse microglia BV2, providing first insights regarding the protective underlying mechanism.
BT and BD extracts, showing no significant toxicity at 100 μg/ml, were evaluated for HepG2 cytoprotection against the insults in pre-incubation assays. The extracts were pre-incubated for 2 and 6h before the application of t-BHP and paraquat respectively and then co-incubated with the insults (4h). Cellular viability (MTT assay) was assessed immediately or 16 hours later, after t-BHP or paraquat insults, respectively. Both BT and BD showed significant cytoprotection in HepG2 against t-BHP with 0,5- and 1-fold increase in cellular viability. However, only BD showed a significant protective effect against t-BHP in BV2 cells with 1-fold increase. Also, only BD showed significant cytoprotection against paraquat in HepG2 with 0,7-fold increase in cellular viability. Higher cellular viability has been confirmed through flow cytometry with a 0,37 fold-decrease in apoptotic cells following incubation with BD. To understand the protective mechanism against t-BHP toxicity, cellular oxidative stress has been quantified in pre-incubation assay (with t-BHP insult) with a 0,6-fold significant decrease in ROS production for both extracts. Moreover, 0,2- and 0,5-fold decreases in NO have been determined following 2h-pre-incubation of BV2 with the BT and BD, respectively and 16h-co-incubation with LPS 1 m g/ml. Further studies including the induction of antioxidant enzyme activities, are warranted.
This work is financed by INTERACT - ISAC project, no. NORTE-01-0145-FEDER-000017, co-financed by the European Regional Development Fund (ERDF) through NORTE 2020 (North Regional Operational Program 2014/2020).