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.
ABSTRACT
In present study, leaf extract of Hoya parasitica Wall. was evaluated for in vitro antioxidant and membrane stabilizing activity along with in vivo gastro intestinal motility and acute toxicity. Five different assays were performed to evaluate antioxidant activity. In DPPH free radical scavenging activity, methanol, ethanol and chloroform extract exhibited IC50 value similar to standard ascorbic acid. The presence of flavonoid and phenolic contents was also similar in all the plant extracts. However, chloroform extract showed remarkable reducing power capacity (69.10% at 200μg/mL). In case of membrane stabilization, the chloroform extract showed maximum inhibition (32.62 %) of haemolysis, whereas the ethanol extract showed a significant (p<0.001) human RBC membrane stabilizing effect. In vivo gastrointestinal motility test indicates significant (p<0.001) increase in gastrointestinal motility by Methanol extract (100 and 200 mg/kg b.w.) and ethanol extract (200 mg/kg b.w.) compared to standard. Highest dose introduced as 1000, 2000 and 3000 mg/kg body weight of each extracts in acute toxicity study and did not shown any sign of toxicity in Swiss albino mice. The result obtained from this study, can be considered as preliminary and further sophisticated investigation is needed to isolate new bioactive compounds that might act as led compounds in future.