Antihyperglycemic activity and standardization of the bioactive extract of cleome droserifolia growing in Egypt

Abstract

Background: Cleome droserifolia herb is well known in the Egyptian folk medicine for the treatment of diabetes. However, a standardized active extract of the herb was never prepared for incorporation into a pharmaceutical dosage form. Materials and Methods: Comparative high performance liquid chromatography (HPLC) chromatographic profi les were established in order to study the ethnopharmacological use of the antihyperglycemic herb using a validated reversed phase-HPLC method which was developed for standardization of the active aqueous extract. A biologically guided fractionation of the antihyperglycemic aqueous extract was carried out in vivo using alloxan induced diabetic rats. Results: The aqueous extract contained the highest percent of the total active fl avonol glycosides (78.20%) compared to the 70% and 50% ethanolic extracts (51.17 and 42.66%, respectively). The aqueous extract and its ethyl acetate fraction possessed the highest antihyperglycemic activities. A standard calibration curve, established for the major bioactive methoxylated fl avonol glycoside (kaempferol-4'-methoxy-3,7-dirhamnoside) at a concentration range of 44-174 μg/ml, showed good linearity with a correlation coeffi cient (R2) of 0.998. The recovery of the method was 100.5%. A high degree of precision (relative standard deviation values <5%) was achieved. The limits of detection and quantifi cation were 0.01 and 0.02 μg/ml, respectively, indicating the sensitivity of the method.Conclusion: The aqueous extract contained the highest percent of the total active fl avonol glycosides. The extract, standardized to contain not <1.5 ± 0.06% of kaempferol-4′-methoxy-3,7-dirhamnoside, was tested at three different dose levels showing a 63.3% activity of that of metformin at100 mg/kg body weight. Furthermore, it raised the blood insulin level by 146.26% at this dose level.