Antidiabetic activity of Ipomoea cairica (L.) Sweet leaves: in-vitro and in-silico antidiabetic potential of isolated flavonoid glycosides and sulphated flavonoids

Antidiabetic activity of methanolic extract, petroleum ether, ethyl acetate and n-butanol fractions of Ipomoea cairica (L.) Sweet leaves was performed in-vitro using α-glucosidase and α-amylase inhibition methods. Phytochemical study of the ethyl acetate fraction which possessed the highest antidiabetic activity led to isolation of five flavonoids for the first time from this plant, including two rare flavonoid sulphates, ombuin-3-sulphate [1] and rhamnetin-3-sulphate [2] and three flavonoid glycosides, kaempferol 7-O-α-L-rhamnopyranoside [3], kaempferol 3,7-di-O-α-L-rhamnopyranoside [4] and quercetin 3-O-α-L-arabinopyranoside [5]. The ¹H and ¹³C NMR of 1 and ¹³C NMR of 2, were reported here for the first time. Compounds [1-4] showed a concentration-dependent in-vitro inhibitory activity against α-glucosidase and α-amylase. Furthermore, in-silico study predicted that compounds (1-5) showed good interactions with α-glucosidase, α-amylase, and protein tyrosine phosphatase 1b.