Evaluation of Antioxidant and Cholinesterase Inhibitory Activities of Hoya parasitica Variegata - An In-vitro Study

Abstract

Aim: Oxidative stress is responsible for the development of different neurological disorders such as Alzheimer’s disease (AD). In the present study, Hoya parasitica variegata belonging to the family Apocynaceae was evaluated for its cholinesterase inhibitory and antioxidant activities with an objective of searching a new natural source to treat different neurological disorders. Study Design: The methanolic extract of H. parasitica was subjected for in-vitro evaluation which included antioxidant and cholinesterase inhibitory activities. Place and Duration of Study: Department of Pharmacy, Southeast University, Banani, Dhaka-1213, Bangladesh, from July to December 2016. Methodology: The cholinesterase inhibitory and antioxidant activities were assessed by total phenol content, flavonoid content, total antioxidant, iron  reducing power capacity, DPPH and hydroxyl radical scavenging capacity, lipid peroxidation inhibition, metal chelating activity as well as acetylcholinestrase (AChE) and butyrylcholinestrase (BChE) inhibitory activities. Results: Total phenolic and flavonoid content of the extract were 53.31 mg of gallic acid and 129.88 mg of quercetin equivalent respectively. The methanolic extract of H. parasitica (MEHP) showed considerable total antioxidant activity and reducing capacity. In DPPH and hydroxyl radical scavenging assay, the MEHP showed IC50 of 485 μg/mL and 39.65 μg/mL respectively. In lipid peroxidation inhibition activity MEHP showed IC50 value of 857.63 μg/mL and exhibited metal chelating activity with IC50 value 961.21 μg/mL. The MEHP represented inhibition of bovine brain acetylcholinesterase and human blood butyrylcholinesterase and the IC50 value was 269.5 μg/mL and 343.14 μg/mL respectively. Conclusion: The results obtained from present study revealed that MEHP has considerable amount of antioxidant activity as well as anti-acetylcholinesterase and anti-butyrylcholinesterase activity suggesting its potential use in different neurological disorders such as AD.