Maximized Extraction of Flavonoid Luteolin from V.negundo L. Leaves: Optimization Using Box-Behnken Design

Background: Luteolin is a flavonoid unveiling various therapeutic activities, found in Vitex negundo L. Thus, there is a need to present process parameters at which maximum amount of luteolin can be extracted from V. negundo L. leaves in “one-run”. Objective: Response surface methodology (RSM) was employed for optimizing the process parameters for the extraction of luteolin from V. negundo L. leaves. The study also compared the efficacy of various traditional and modern extraction methods for luteolin extraction. Methods: Extraction conditions (solvent to drug ratio, extraction temperature and extraction time) were optimized by RSM, Box-Behnken Design (BBD). Quantification of luteolin in various extracts was done through High Performance Liquid Chromatography (HPLC). Results: Hot solvent extraction by reflux technique stood out to be the best technique and methanol was found to be the most effective solvent for luteolin extraction.Through the use of BBD, the optimal conditions for luteolin extraction were established as: solvent to drug ratio- 17.7 mL/g, extraction temperature- 55.5°C and extraction time-2.04 hours. Under such conditions 7.32 %w/w of luteolin was yielded which was close to predicted value of 7.29 %w/w. Conclusion: Reflux technique stood out to be the best among all the studied modes of extraction and methanol proved to be the most effective solvent. Moreover, all the three variables significantly affected the luteolin extraction. Our study shows the applicability of a statistical technique, RSM in phytocompound extraction field. This makes the optimization technique cheap and less laborious than the traditional optimization method.