Bioactivity-guided isolation of kaempferol as the antidiabetic principle from Cucumis sativus L. fruits

This study was aimed at isolating the antidiabetic principle of Cucumis sativus fruit using in vitro and in vivo antidiabetic model. Antidiabetic activity was monitored using in vitro -amylase and -glucosidase inhibition, and in vivo alloxan-induced diabetic rats models. The active principle was isolated using column chromatography and identified with high performance liquid chromatography. The extract and chromatographic fraction B from C. sativus fruit lowered blood glucose of alloxan-induced diabetic rats. The extract inhibited -amylase and -glucosidase with IC50 values of 652.43 and 540.42 g/mL, respectively. Similarly, Fraction B inhibited -amylase and -glucosidase with IC50 51.24 and 29.37 g/mL, respectively. Fraction B also reversed altered lipid profile and oxidative stress biomarkers of diabetic rats. HPLC fingerprint revealed that the Fraction B was kaempferol. Data obtained from this study showed that kaempferol isolated from C. sativus is responsible for its -amylase and -glucosidase inhibition, glucose lowering, antidyslipidemic, and antioxidant activities. Practical applicationsConsumption of cooked or fresh Cucumis sativus L. fruits could help in the management of diabetes and reduction of postprandial glucose. Furthermore, the fruit extracts could be developed into phytoceutical supplements for managing diabetes and its associated complications including dyslipidemia and oxidative stress.