Selection of elite germplasms for industrially viable medicinal crop Bacopa monnieri for bacoside A production: An HPTLC-coupled chemotaxonomic study

Abstract

BackgroundBacopa monnieri (L.) Wettst., commonly known as Brahmi or water hyssop is an age old Ayurvedic nootropic and cognitive booster used as a medicinal food and also in an array of pharmaceutical and healthcare products as a memory enhancing tonic. It is a high value medicinal crop in modern healthcare industry owing to a number of bioactive pharmaceuticals of which bacoside A is of prime neuropharmacological importance. The bacosides-enriched standardized extract of Bacopa is being used and investigated for clinical purpose. ObjectivesThe objectives of this study are to analyze the intrinsic intra-specific variation in bacoside A in B. monnieri populations, to identify the elite (high bacoside A yielding) chemotypes of B. monnieri, to investigate the in vitro acetylcholinesterase (AChE)-inhibitory activity of the B. monnieri elite chemotypes and to find out the cytotoxicity and genotoxicity of B. monnieri employing Allium cepa root tips.Material and methods: This present work describes a quick, validated and reproducible high-performance thin layer chromatography (HPTLC) method to estimate bacoside A content from 25 chemotypes of B. monnieri procured from 25 districts of 8 states of India. Further, an evidence-based approach was followed to validate the reported nootropic activity of the aqueous extracts of the plants by assessing their AChE inhibitory activity. Finally, the genotoxicity of an elite (high bacoside A producing) chemotype was assessed using Allium cepa root tip meristematic cells. ResultsB. monnieri chemotype BM1 (collected from North 24 Pgs, West Bengal) (7.55 μg) was found to possess the highest amount of bacoside A followed by BM3 (6.43 μg) and BM6 (6.02 μg) chemotypes collected from Jalpaiguri, West Bengal and Ranchi, Jharkhand respectively. Chemotype BM 25 (2.17 μg) exhibited least amount of bacoside A. Bacoside A content ranged between 2.17–7.67 μg across 25 chemotypes of B. monnieri. The strongest AChE inhibitory activities (IC50 values of 259.45 and 267.89 mg/mL respectively) were showed by the highest bacoside A containing chemotype BM1 (259.45 mg/mL). Allium cepa root tip meristematic cell assay also revealed the lack of mitotoxic and cytotoxic property of the plant extract. ConclusionThe present rapid, reproducible and validated HPTLC provides an efficient tool to determine the quantitative variation in the bacoside A content in naturalB. monnieri chemotypes. This method may be applied to select high bacoside A producing elite genotypes for further propagation and commercialization of this significant neuro protectant for pharmacological industry. Besides, it’s in vitro AChE inhibitory property directly supports the popular use of the plant as a nootropic agent. Lack of genotoxicity of the plant extracts evidences its age old use as a medicinal food and commercial memory booster.