|Antioxidative and Neuroprotective Activities of Loranthus parasiticus Extracts in NG108-15 Mouse Neuroblastoma Cell Line
Wong Daniel Zin Hua & Habsah Abdul Kadir
Biomolecular Research Group, Biochemistry Program, Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia, email: email@example.com
The aim of this study was to investigate the antioxidative and neuroprotective effects of Loranthus parasiticus (L.) Merr, which is believed in treating several neurodegenerative diseases. The dried leave powder of Loranthus parasiticus was extracted into ethanol, ethyl acetate and aqueous extracts. The antioxidant activity of these extracts were tested by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and reducing power activity assay. Results showed that aqueous extract yielded the highest IC50 value of 16.40 ± 0.71 µg/ml in DPPH radical scavenging activity and possessed the strongest reducing power activity. The total phenolic content in all the extracts were determined spectrometrically according to the Folin-Ciocalteu procedure and calculated as gallic acid equivalents per gram of dry weight (GAE/gDW). Results showed that antioxidant activity was closely related to the content of phenolic compounds as evident by aqueous extract showing the highest value of 59.55 ± 0.61 mg GAE/gDW. In neuroprotective study, aqueous extract decreased dose-dependently (3.125-100 ug/ml) on hydrogen peroxide-induced cell damage in NG108-15 mouse neuroblastoma cell line. At 100 ug/ml, aqueous extract showed the highest neuroprotective effect with 75.23 ± 2.376 % cell viability. The restoration of intracellular glutathione, a major endogenous antioxidant was also observed and suggested to be an underlying mechanism in the neuroprotective effects. Furthermore, morphological analysis by 4´, 6-diamidino-2´-phenylindole, dihydrochloride (DAPI) staining demonstrated that NG108-15 cells treated with hydrogen peroxide exhibited apoptotic features, while such changes was reduced in cells pre-treated with aqueous extract. In conclusion, these results suggested that aqueous extract of L. parasiticus may be used as a potent antioxidant and neuroprotectant in treating or preventing degenerative diseases where oxidative stress is implicated.