Efficient Vortex-assisted Extraction of Phorbol Esters from Jatropha Leaves and Correlation Between Leaves and Seeds in Phorbol EstersContent

Abstract

This work aimed to optimise and validate the vortex-assisted extraction with high-performance liquid chromatographyultraviolet detection (HPLC-UV) method to quantify phorbol esters (PEs) in Jatropha leaves. Additionally, to evaluate the correlation between PEs content in leaves and seeds. The results of PEs content were expressed as equivalent of the major Jatropha phorbol ester, 12-deoxy-16-hydroxyphorbol-4'-[12',14'-butadienyl]-6'-[16',18',20'-nonatrienyl]-bicyclo[3.1.0]-hexane- (13-O)-2'-[carboxylate]-(16-O)-3'-]8'-butenoic-10']ate (DHPB) . One-variable-at-time strategy and 25-1 V factorial fractional design were employed to determine the effects of solvent type, volume, stirring frequency, extraction time and cycles on yield. The quantification was performed using HPLC-UV. The optimum conditions were three extractions with 2% tetrahydrofuran:dichloromethane (1:1) in methanol (THF:DCM/MeOH). The sample:solvent ratio was 1 mg:25 μL, and the vortex stirring was 2200 rpm for 5 minutes. The method showed good linearity (R2 0.999), recoveries (97 to 105%), selectivity and repeatability (RSD 1.93-7.95%). In addition, good limits of detection and quantification of 2.19 and 6.65 ng μL-1, respectively, were noted. DHPB content in leaves and seeds ranged from 0.01 to 0.38 mg g-1 and 0.41 to 1.82 mg g-1, respectively. There is a statistically significant and positive linear relationship between leaves and seeds for DHPB content. These results may have practical application in analysing and predicting the amount of PEs in Jatropha leaves for environmental safety studies and the selection of better varieties for genetic improvement.