Quantitative estimation of quercetin of some selected edible plants of West Bengal by high-performance thin-layer chromatography densitometry method

Introduction: Quercetin is a polyphenol, widely found in most edible fruits and vegetables. This plant pigment provides cardiovascular, anti-inflammatory, antidiabetic, asthma, and many more health benefits. Objective: The aim of this study is to quantify the quercetin by high-performance thin-layer chromatography (HPTLC) method from the methanolic leaf extracts of three edible plants of Bengal, viz., Nyctanthes arbor-tristis L., Oxalis corniculata L., and Polygonum plebeium R.Br. Materials and Methods: HPTLC was carried out on aluminum-backed plate precoated with silica gel 60 F254, using the solvent system of toluene, ethyl acetate, formic acid, and methanol (5.5:3:1:0.5 v/v/v/v). The method validation was done according to the International Conference on Harmonization guidelines in terms of linearity, limit of detection, limit of quantification, accuracy, precision, and specificity. Results: The desired compound was well separated using the solvent system toluene, ethyl acetate, formic acid, and methanol (5.5:3:1:0.5 v/v/v/v) which gave a sharp and well-defined band with Rf 0.60 for quercetin. The calibration curves showed a good linear correlation coefficient (R2 = 0.9774). The linearity range was found to be 20–100 (μg/spot). Among the selected plants, the highest amount of quercetin was found in the leaf extracts of O. corniculata L. (220.035 ± 0.06 mg/100 g) and the lowest for N. arbor-tristis L. (31.253 ± 0.99 mg/100 g). Conclusion: The proposed HPTLC method for quercetin estimation was found to be simple, cost-effective, precise, and accurate and can be used for the quality control of plant material. O. corniculata L. was found to be a potent source of quercetin as it possesses a decent amount of quercetin.