TLC-densitometric analysis of didehydrostemofoline in Stemona collinsiae roots

Abstract

Stemona collinsiae (Stemonaceae) has been traditionally used as a natural pesticide for a long time. Didehydrostemofoline is a major active component that possesses potent insect toxicity. A simple thin layer chromatography (TLC) densitometric method has been developed for determination of didehydrostemofoline in S. collinsiae root extract at UV maximum absorption 300 nm. The analysis was performed on TLC aluminum sheets precoated with silica gel 60 F254 using dichloromethane: ethyl acetate: methanol: ammonium hydroxide 70:25:5:1 as a mobile phase. The method was validated for linearity, precision, accuracy and limit of detection (LOD) and limit of quantitation (LOQ). The linearity was within the concentration range of 40.48-323.84 ng/spot with correlation coefficient (r) 0.995. Intraday and interday precision studies showed the relative standard deviation (RSD) <4%. Accuracy of the method was determined by a recovery study of didehydrostemofoline at 3 different levels and was found to be 95.9, 104.3 and 103.5%, with an average of 101.2%. The LOD and LOQ were 6.88 and 22.94 ng, respectively. The contents of didehydrostemofoline in the methanol extract and in dried root powder of S. collinsiae were 1.27±0.09, 0.74±0.05% w/w, respectively. The developed method was simple, precise, specific and accurate and could be used for quantification of didehydrostemofoline in plant materials, extracts and products containing this compound. It would be suitable for routine analysis of many samples of S. collinsiae extract and its products simultaneously. © ISHS.