Identification of Cholinesterase Inhibitors and Antioxidant Molecules from Leaf of Clerodendrum splendens G. Don (Verbenaceae) Using GC-MS

Abstract

More than half of people with dementia globally have Alzheimer's disease (AD). Memory and cognitive impairment is one of the clinical symptoms of AD. Currently there is no cure for AD; hence the need arises to search for new neurotherapeutic agent. The rationale of this research is to identify molecules with cholinesterase inhibition and antioxidant potential from Clerodendrum splendens using GC-MS. The powdered leaves of Clerodendrum splendens G.Don (Verbenaceae) was extracted by successive method. Cholinesterase inhibitory activities were measured according to Ellman's method. Antioxidant capacity was assessed using standard in vitro chemical analysis and bioactive compounds were identified using GC-MS analysis. The ethyl acetate fraction showed the highest acetylcholinesterase inhibitory activity at 1 mg/mL with IC50 of 0.42±0.01 mg/mL (81.11±1.7%) in comparism with eserine (IC50 of 0.050±0.01 mg/mL). The ethyl acetate fraction at 1 mg/mL also showed good metal chelating activity (IC50 of 0.287±0.02 mg/mL) in comparism with EDTA (IC50 = 0.086±0.00 mg/mL). The ethyl acetate fraction showed highest nitric oxide scavenging activity (IC50 of 0.564±0.1 mg/mL) when compared to ascorbic acid (IC50 of 0.064±0.06 mg/mL). The total anthocyanin was higher in ethyl acetate fraction (52.184±2.0 mg cyanidin 3-glucoside/100g of sample). The GC-MS analysis of the ethyl acetate fraction revealed fifty-eight (58) compounds which include 9,12- Octadecadienoic acid (Z,Z)- (RT-15.974, 13.56%), n-Hexadecanoic acid (RT-14.802, 8.88%). Molecules identified by GC-MS from the ethyl acetate fraction could be possible drug lead for the treatment of AD.