Neuroprotective activity of Swertia iberica (Gentianaceae) on BV-2 microglia cells

The Swertia L., belonging to the Gentianaceae family, includes 166 species worldwide (http-1), and 2 species growing in Türkiye (http-2). Swertia exhibits various pharmacological activities, including anticancer, antipyretic, analgesic, antidiabetic, antibacterial, antioxidant, hepatoprotective, and neuroprotective. Swertia species contain xanthones, iridoids/secoiridoids, flavonoids, alkaloids, andterpenoids (Kshirsagar et al., 2019). The aerial parts of S. iberica were extracted with methanol and partitioned by n-hexane, n-butanol, and water, respectively. The n-butanol extract was chromatographed over a polyamide column eluting with stepwise H2O–MeOH gradient to obtain fractions. Alzheimer’s disease, a progressive neurodegenerative disease, affects learning and memory resulting from cholinergic dysfunction. Scopolamine has been employed to induce Alzheimer’s disease-like pathology in vivo and in vitro through the alteration of cholinergic systems (Puangmalai et al., 2017). S. iberica extracts were applied to BV-2 microglia cells at 200 μg/mL concentrations to 3.12 μg/mL. Sodium valproate was used as a positive control. BV-2 cells were pretreated with extracts and fractions. 1 hour later, scopolamine (4mM) was applied. After 24 hours of incubation, the cell viability was evaluated using the MTT method. All tested extracts showed neuroprotective effects but, the water extract was found to be significant at the doses of 12.5-50 μg/mL (p<0.01). The isolation and structure elucidation studies to determine the active compounds are ongoing.

Keywords: Swertia iberica, cytotoxicity, Gentianaceae