Screening Indigenous Medicinal Plants of Northeast India for Their Anti-Alzheimer’s Properties

Roohollah Sobhani,Kripamoy Aguan,Atanu Bhattacharjee,Sivaprasad Mitra,Amarta Kumar Pal

doi:10.5530/pj.2017.1.9

Abstract

Introduction: Alzheimer’s disease (AD) is a progressive neurologic disease of the brain that affects intellectual abilities, reasoning and memory. Acetylcholine (ACh) is involved in the maintenance of cognitive process. Pathologically, ACh production is compromised in the brains of AD affected people. Presence of acetylcholinesterase (AChE) in the synaptic cleft, which hydrolyzes ACh, further decreases the ACh-levels, and thereby, additionally compromises cognition. The tribal people of North East India have been using indigenous plants as traditional medicine for brain disorders. We assayed whether the plants used in the traditional tribal knowledge for the treatment of brain disorders might contain better AChE-inhibitors. Methods: We collected 10 traditional medicinal plants from Northeast India. A total of 39 plant extracts were prepared using three solvent systems. The Acetylcholinesterase (AChE) activity was measured with Ellman method. The experiment was done in triplicate for each level of inhibitor. The activity was measured at 412 nm wavelength using Plate Reader. The standard student t-test was used to show significant difference in IC50 values between extracts. Results: The result are reported based on Km, Vmax, IC50 (μg/μl), percentage inhibition and inhibition pattern. Two extracts had competitive inhibition, 11 extracts had mixed inhibition, 2 extracts had non-competitive inhibition, 11 extracts had uncompetitive inhibition and 4 extracts did not provide any proper pattern. The IC50 for these plant extracts were at the range of 0.51-12.4 μg/μl. Notably, Cinnamomum camphora (leaf: chloroform), Litsea glutinosa (stem; chloroform), and Litsea glutinosa (stem; methanol) showed IC50 values of 0.51, 0.53 & 0.81 μg/μl, respectively.

Highlights

Alzheimer’s disease (AD) is a progressive neurologic disease of the brain that affects intellectual abilities, reasoning and memory
It is worth mentioning that the plants which were collected from Botanical Survey of India (BSI) and adjoining area of Shillong these plants may be found in other parts of India but we selected because these plants are being used by traditional healers of North East India for brain disorders
We found 20 plant extracts having more than 20% inhibition and the above mentioned plants displayed % inhibition range varying from 40-54%

Summary

Introduction

Alzheimer’s disease (AD) is a progressive neurologic disease of the brain that affects intellectual abilities, reasoning and memory. The tribal people of North East India have been using indigenous plants as traditional medicine for brain disorders. We assayed whether the plants used in the traditional tribal knowledge for the treatment of brain disorders might contain better AChE-inhibitors. Neurofibrillary tangles, Amyloid plaques and loss of cholinergic neurons are three pathological findings commonly observed in the cerebral cortex of Alzheimer’s disease cases.[5,6,7,8] Based on the findings that there exist a correlation between cholinergic system abnormalities and intellectual impairment, “cholinergic hypothesis” has been put forward in the functioning of memory and accepted as the foremost hypothesis in the field of AD.[9,10,11] relationships between levels of acetylcholine and AD have been a challenge. It is accepted that the acetylcholine dysfunction may not be the primary cause of AD but may be a consequence of the disease.[9]

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Discussion

Conclusion