Determination of quercetin, plumbagin and total flavonoids in Drosera peltata Smith var. glabrata Y.Z.Ruan

Background: Drosera peltata Smith var. glabrata Y.Z.Ruan, a kind of wild carnivorous plants in the family Droseraceae, has been used for the treatment of rheumatism and bruises in Chinese folk. None of compounds in this herb has been quantified in the previous studies. Objective: To develop a validated and reliable HPLC method for the simultaneous determination of two bioactive constituents - quercetin and plumbagin, and establish a simple UV spectrophotometry method for the analysis of total flavonoids content. Materials and Methods: Chromatographic separation was performed by using a HPLC system consisting of an Agilent Eclipse XDB C ₁₈ column and a gradient elution system of acetonitrile and water (containing 0.1% phosphoric acid, V/V) within 20 minutes. Comparing with quercetin complex with Al(NO ₃ ) ₃ , the total flavonoids were determined by UV spectrophotometry at 269 nm. Results: Both methods were validated for linearity (r ²≥0.9994 for quercetin and plumbagin in the HPLC method, r ² =0.9994 for quercetin in the UV spectrophotometry method), precision (The within-day and between-day variability was less than 0.738% and 1.64% for quercetin and plumbagin in the HPLC method, and was less than 1.67% for quercetin in the UV spectrophotometry method.) and recovery (The recoveries of the HPLC method were 96.7-100.4% and 97.4-100.4% for quercetin and plumbagin, respectively, and the recovery of the UV spectrophotometry method was 96.7-99.6% for quercetin.) Conclusion: The proposed methods are simple and accurate, and could be practiced to rapidly determine quercetin, plumbagin and total flavonoids in the herbal drug, which provide effective approaches for quality control.