Thin-layer chromatographic study on the identification of the Solanum nigrum L.from Anhui,China
Objective To establish a qualitative method using thin-layer chromatography with diosgenin as the index component.Methods According to the experimental method of the Chinese Pharmacopoeia 2020 edition Part Four General Rules(0502),the experimental conditions(using different developing agents,extraction methods,colorants,sample amounts,and thin layer plates)were investigated.The final determination was to take 2 g of the product powder(sieved through the second sieve),add 50 ml of methanol,ultrasound for 30 min(frequency of 45 kHz),filter,evaporate the filtrate to dryness,add 10 ml of 2 mol/L hydrochloric acid solution to the residue,and heat hydrolysis for 1 h,cool down,add 30 ml of trichloromethane,heat and reflux for 30 min,extract the trichloromethane solution,and concentrate to 2 ml in a water bath.Results Using silica gel G plate as the thin-layer plate,trichloromethane methanol(20:0.2)as the developing agent,and 5%phosphomolybdate ethanol solution as the chromogenic agent,the spots were heated at 105℃ until they were clear.In the chromatogram,spots of the same color appeared at the corresponding positions of the test and control samples.Conclusion The chromatographic spots of thin-layer chromatography are clear and have good separation,which can be used for the qualitative identification of Solanum nigrum L.by thin-layer chromatography.