Selective α-glucosidase inhibitory activity of (+)-eupenoxide and 3-ketone derivatives produced by the endophytic fungus of Aspergillus sp.

α-Glucosidase and α-amylase are two important glycosidases involved in carbohydrate metabolism. Inhibitors of these enzymes are considered crucial therapeutic agents for carbohydrate absorption disorders such as diabetes and obesity. However, the inhibition of salivary amylase can result in undigested starch reaching the stomach, causing indigestion and potentially leading to gastric and duodenal ulcers as well as gastritis. Selective inhibitors that possess α-glucosidase inhibitory activity without affecting α-amylase are needed to address this issue. It has been revealed that (+)-eupenoxide and its 3-ketone derivative, produced by the endophytic fungus of Aspergillus sp. C-1-1 strain associated with Catharanthus roseus, selectively inhibits α-glucosidase. Additionally, from the α-glucosidase inhibitory activity of related compounds, we have successfully deduced the chemical structure feature necessary for α-glucosidase inhibition.