Studies on α-glucosidase, aldose reductase and glycation inhibitory properties of sesquiterpenes and flavonoids ofZingiber zerumbetSmith

Abstract

Eight known phytochemicals, four sesquiterpenes and four flavonoids of Zingiber zerumbet were screened against α-glucosidase enzyme, aldose reductase enzyme and antiglycation property under in vitro conditions. The results established kaempferol-3-O-methylether as a potent inhibitor of α-glucosidase enzyme with an IC50 value of 7.88 μM. In aldose reductase enzyme inhibition assay, all the compounds except zerumbone epoxide showed good to excellent inhibition properties. Among these, the flavonoid compounds were found to be potent aldose reductase inhibitors compared with the four sesquiterpenes. In addition, compounds such as α-humulene, kaempferol, kaempferol-3-O-methylether and 3″,4″-O-diacetylafzelin displayed potent antiglycation properties. From overall results, we found that kaempferol and kaempferol-3-O-methylether are potent inhibitors of α-glucosidase enzyme, aldose reductase enzyme and glycation reaction, the three main targets of drugs for the treatment of diabetes and its complications.

Chemical Constituents of Muehlenbeckia tamnifolia (Kunth) Meisn (Polygonaceae) and Its In Vitro α-Amilase and α-Glucosidase Inhibitory Activities

“…The remaining five compounds exhibited no inhibitory activity over α-glucosidase at the maximum dose tested (less than 1% of enzyme inhibition) and only trans - p -coumaric acid exhibited 27% of enzyme inhibition. The activity of Afzelin (Kaempferol 3- O -rhamnoside) was 20-fold higher compared to the activity reported by Ajish et al [24], who obtained an IC 50 value of 81.16 μM. The method described previously in the methodology measures the pNP released during 60 min which allows us to obtain more reliable data by measuring enzymatic catalysis for a long period of time instead of short periods or even end point measurements.…”

“…Moreover, the flavonoids have demonstrated to be moderate to strong inhibitors of α-glucosidase, with IC 50 values below 100 μM [24,25,26,27,28]. Linoleic acid was demonstrated to be the most potent compound, followed by afzelin, (+)-catechin and quercitrin.…”

Antidiabetic potential: in vitro inhibition effects of some natural phenolic compounds on α‐glycosidase and α‐amylase enzymes

“…They are oral drugs, which do not have a pancreatic‐centered method of action . We speculate that after oral using of naturel phenolic compounds, which had antioxidant activity, the postprandial ascent in blood glucose amount is dose‐dependently reduced, and glucose‐induced insulin secretion is decreased . Because of reduced postprandial hyperglycemia and hyper‐insulinemia by AGIs, hepatic lipogenesis, the triglyceride uptake into adipose cell, and triglyceride amounts are decreased .…”

Litsea japonicaExtract Inhibits Aldose Reductase Activity and Hyperglycemia-Induced Lenticular Sorbitol Accumulation in db/db Mice

“…Three flavonoids, epicatechin, quercitrin, and afzelin, were identified in LJE [ 10 ]. Epicatechin, quercitrin, and afzelin are the potent AR inhibitors, with IC 50 values of 79 μ M, 0.17 μ M, and 5.54 μ M, respectively [ 23 – 25 ]. Moreover, catechin prevented N -methyl- N -nitrosourea-induced cataracts and lens epithelial cell apoptosis in rat [ 26 ].…”