Hyperoside

Abstract: Hyperoside, an active compound from the genera of Hypericum and Crataegus, was reported to have antioxidant, antihyperglycemic, anticancer, anti-inflammatory, and anticoagulant activities. Vascular inflammatory process has been suggested to play a key role in initiation and progression of atherosclerosis, a major complication of diabetes mellitus. Thus, in this study, we attempted to determine whether hyperoside can suppress vascular inflammatory processes induced by high glucose (HG) in human umbilical vein endothelial cells (HUVECs) and mice. Data showed that HG induced markedly increased vascular permeability, monocyte adhesion, expressions of cell adhesion molecules (CAMs), formation of reactive oxygen species (ROS), and activation of nuclear factor (NF)-κB. Remarkably, all of the above-mentioned vascular inflammatory effects of HG were attenuated by pretreatment with hyperoside. Vascular inflammatory responses induced by HG are critical events underlying development of various diabetic complications; therefore, our results suggest that hyperoside may have significant therapeutic benefits against diabetic complications and atherosclerosis.

Abstract: As a part of our ongoing effort to identify anti-diabetic constituents from natural sources, we examined the inhibitory activity of the methanol extracts of 12 species of the genus Artemisia, against α-glucosidase and protein tyrosine phosphatase 1B (PTP1B). The methanol extracts of different species exhibited promising α-glucosidase and PTP1B inhibitory activities. Since the methanol extract of Artemisia capillaris exhibited the highest α-glucosidase inhibitory activity together with significant PTP1B inhibitory activity, it was selected for further investigation. Repeated column chromatography based on bioactivity guided fractionation yielded 10 coumarins (esculetin, esculin, scopolin, isoscopolin, daphnetin, umbelliferone, 7-methoxy coumarin, scoparone, scopoletin, 6-methoxy artemicapin C), 8 flavonoids (hyperoside, quercetin, isorhamnetin, cirsilineol, arcapillin, isorhamnetin 3-robinobioside, linarin, isorhamnetin 3-glucoiside), 6 phenolic compounds (1,5-dicaffeoylquinic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid methyl ester, 4,5-dicaffeoylquinic acid, 3-caffeoylquinic acid), and one chromone (capillarisin). Among these compounds, esculetin, scopoletin, quercetin, hyperoside, isorhamnetin, 3,5-dicaffeoylquinic acid methyl ester, 3,4-dicaffeoylquinic acid, and 1,5-dicaffeoylquinic acid exhibited potent α-glucosidase inhibitory activity when compared to the positive control acarbose. In addition, esculetin and 6-methoxy artemicapin C displayed PTP1B inhibitory activity. Interestingly, all isolated dicaffeoylquinic acids showed significant PTP1B inhibitory activity. Therefore, the results of the present study clearly demonstrate the potential of the A. capillaris extract to inhibit α-glucosidase and PTP1B. These inhibitory properties can be largely attributed to a combination of different chemical structures, including coumarins, flavonoids, and dicaffeoylquinic acids, which could be further explored to develop therapeutic or preventive agents for the treatment of diabetes.