An optimized solid-liquid method for rapid extraction of phorbol esters from Mozambican Jatropha seeds

The method of extraction of phorbol esters from Jatropha curcas L. (Jatropha) seed was optimized, using an experimental design, and validated in this study. Variables such as extraction time, vortex-stirring rate, sample:solvent ratio, solvent type and extraction cycles, were selected and their influence on the extraction yield was screened by Plackett-Burman design. Thereafter, the three factors (extraction time, stirring rate and sample:solvent ratio) were optimized by response surface methodology based on Box-Behnken design. The results revealed that the best conditions to achieve optimum response are sample:methanol ratio of 1 mg:50 μL, two extraction cycles under vortex stirring at 3200 rpm for 3 min/cycle. This method shows good recoveries (84-95%), repeatability (RSD = 1.89%), linearity (R2 = 0.999), robustness, limits of detection (2.19 ng μL−1) and quantitation (6.65 ng μL-1). Using this method, phorbol esters can be extracted for quantification purposes, toxicological studies and application as biopesticides and anti-HIV agents.