Context: Finding effective therapies for neurodegenerative diseases is of utmost importance for the aging population. Plants growing in Iran are rich sources of antioxidants and active phytochemicals.
Objective: The protective capacity of plants, with a special focus on those with reported antioxidant or neuroprotective potential or nervous system-related applications in folk medicine, was tested against oxidative stress-induced apoptosis.
Materials and methods: Aerial parts of 20 plants including Carthamus, Salvia, and Stachys species were extracted with 80% methanol and dichloromethane and preincubated with neuronal PC12 cells for 3 h. Oxidative stress and apoptosis were induced by hydrogen peroxide (75 µM, 1 h exposure). Cell viability and intracellular reactive oxygen species (ROS) were measured by MTT and 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assays, respectively, while apoptosis was determined by annexin V-FITC/propidium iodide staining by a flow cytometer.
Results: Eighty percent methanol extracts of Carthamus oxyacantha Bieb. (Asteraceae), Salvia santolinifolia Boiss. (Lamiaceae), and Salvia sclarea L. (Lamiaceae) at the concentration of 100 μg/ml showed significant neuroprotection in the MTT assay by 38.7, 34.7, and 39.5%, respectively, and inhibited intracellular ROS by 48.6, 61.9, and 61.4%, respectively. The first two extracts also significantly inhibited apoptosis. Dichloromethane extracts of C. oxyacantha and Stachys pilifera Benth. (Lamiaceae) at the concentration of 25 μg/ml showed neuroprotection by 27.5 and 26.5%, respectively, and inhibited ROS by 44.5 and 39.4%, respectively.
Conclusion: The above-mentioned plants seem to have important biological activities and their further study may lead to the discovery of new natural therapeutics useful against disorders such as Alzheimer and Parkinson diseases.
Keywords: Medicinal plants; PC12; reactive oxygen species.