Quantitative Estimation of Immunomodulatory Flavonoid Quercetin by HPTLC in Different Leafy Vegetables Available in West Bengal

Introduction: Leafy vegetables are commonly consumed medicinal plants used in various metabolic and infectious diseases. Additionally, their antiviral, antioxidant, anticancer, and antihypertensive activities have been reported in the literature. Objectives: To determine the quantity of immunomodulatory flavonoid, quercetin in different types of leafy vegetables available in West Bengal by using a simple validated HPTLC method. Materials and Methods: The chromatographic analysis was performed by using aluminium-backed silica gel 60 F254 plates with Toluene–Ethyl acetate–Formic acid 5:4:0.2 (%v/v) as the mobile phase. The method was validated according to the ICH guidelines. Results: The total flavonoid content (TFC) in the four leafy vegetables studied varied between 58.10 to 12.28 mg QE/g. Well-separated and compact spots (Rf) of quercetin (0.55±0.03) were detected. The regression equation obtained was y = 0.0011x - 0.0569, with a correlation coefficient (R²) of 0.9939. The linearity range (μg/spot) was 60-160. The LOD/LOQ (ng/spot) was 6.09/18.47. Murraya koenigii (0.1992±0.037 %w/w) contained the maximum amount of quercetin compared to Ipomoea aquatic (0.1501±0.039%w/w), Coriandrum sativum (0.1430±0.061%w/w) and Trigonella foenum- graecum (0.1201±0.055%w/w) in methanolic extract. Conclusion: This study revealed that the validated HPTLC method was simple, accurate and sensitive for separating and quantifying quercetin in different leaf vegetables. Quercetin content was highest in Murraya koenigii (0.1992±0.037 %w/w), and least in Trigonella foenum-graecum (0.1201±0.055 %w/w). The developed method might be used further in standardizing and quality control of secondary metabolites in herbal formulations.