Antidiabetic activity screening and nmr profile of vegetable and spices commonly consumed in Indonesia

Abstract Apart from their nutritional value, vegetables and spices were empirically known to have functional properties such as antioxidant and antidiabetic activity. However, scientific evidence of these health effects is limited. In our effort to find potent raw material for antidiabetic functional food development, α-glucosidase inhibition and antioxidant activity of 15 Indonesian vegetables and spices methanolic extracts were screened. Their phytochemical profiles were assessed by determining total phenolic content (TPC) and 1H NMR fingerprinting. The results showed that the Syzygium polyanthum, Pluchea indica, Etlingera elaitor, and Cosmos caudatus had the highest GIA (IC50 11.76 ± 0.32, 12.17 ± 0.18, 53.13 ± 2.87, and 61.33 ± 1.21 μg/ml, respectively). The AA and TPC of the four samples were also higher than the others. The 1H NMR profiles of the active samples were different from the non-active samples mainly in the aromatic region. Further observation of the spectra revealed that caffeoylquinic derivatives and esculetin were identified in P. indica; while gallic acid, syringic acid, and myricetin were identified in S. polyanthum. These compounds were known to have antidiabetic activity through different mechanisms.