Validation of a method for diosgenin extraction from fenugreek (Trigonella foenum-graecum L.)

Background. Diosgenin is a very important plant secondary metabolite and raw material for the drug industry. Plant sources rich in diosgenin include yam (Dioscorea spp.) and fenugreek (Trigonella foenum-graecum L.). A method for diosgenin extraction from yam extracts has previously been validated, but its extraction from fenugreek plants still requires validation. In addition, all available methods require time-consuming additional purification steps. The present study was aimed at developing a low cost, less time-consuming single-step method for diosgenin extraction from fenugreek. Material and methods. This study represents a method developed for diosgenin extraction from fenugreek plants without any additional/supportive purification methods such as chromatography or thin-layer chromatography. Diosgenin yield estimation and purity analysis by HPLC method, along with accuracy and precision analysis, is presented. Results. Five different fenugreek varieties were subjected to a newly developed diosgenin extraction method, and an HPLC chromatogram showed a single peak corresponding to diosgenin. Yield was determined by the standard curve method. Limit of detection (LOD) and limit of quantification (LOQ) for the assay were found to be 0.0312 and 0.102 μg, respectively; t calculated for slope and other statistical parameters were found to be significant (P value < 0.001) for this method. Conclusion. We have developed a fast, accurate and low cost method for diosgenin extraction from fenugreek. Although the authors have studied this method only in fenugreek plants, it could be applied to the extraction of a few other plant secondary metabolites, which will help researchers to save time and effort.