Endothelial cell injury caused by reactive oxygen species (ROS) plays a critical role in the pathogenesis of cardiovascular diseases. Omentin, an adipocytokine that is abundantly expressed in visceral fat tissue, has been reported to possess anti-inflammatory and antidiabetic properties. However, endothelial protective effects of omentin against oxidative stress remain unclear. This study aimed to evaluate the protective effect of omentin against hydrogen peroxide (H2O2)-induced cell injury in human umbilical vein endothelial cells (HUVECs). Cytotoxicity and cytoprotective effects of omentin were evaluated using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The apoptotic activity of HUVECs was detected using Annexin-V/PI and Hoechst 33258 staining methods. Antioxidant activity of omentin was evaluated by measuring both reactive oxygen species (ROS) levels and glutathione peroxidase (GPx) activity. No cytotoxicity effect was observed in HUVECs treated with omentin alone at concentrations of 150 to 450 ng/ml. MTT assay showed that omentin significantly prevented the cell death induced by H₂O₂ (p < 0.001). Hoechst staining and flow cytometry also revealed that omentin markedly prevented H₂O₂-induced apoptosis. Moreover, omentin not only significantly inhibited ROS production (p < 0.01) but also significantly (p < 0.01) increased GPx activity in HUVECs. In conclusion, our data suggest that omentin may protect HUVECs from injury induced by H₂O₂.

Background: Inflammation abrogates cellular organization and tissue homoeostasis, resulting in redness, swelling, heat, pain, and loss of function. A model of carrageenan-induced paw edema (CIE) is commonly utilized to test anti-inflammatory substances. Based on the ability of Lepisanthes alata (LA), a tropical plant that is rich in phytochemicals like polyphenols, this study assessed the optimal dose and the health benefits of LA in rats that had been induced with carrageenan to develop paw swelling. Methods: Twenty-four male Wistar rats were divided into four groups to which carrageenan was administered, after which, distilled water at oral dose (C + DW), sodium diclofenac 25 mg/kg (C + DS), LA extract in 250 mg/kg (C + LA250), and 500 mg/kg (C + LA500) was given, respectively. Paw edema was assessed in 24 h. Pain was assessed using the Rat Grimace Scale (RGS), cytokines, antioxidant activity, and tissue changes. Results: LA at 250 and 500 mg/kg significantly decreased paw edema and inflammatory markers in the results of both studies. Remarkably, LA 250 mg/kg significantly decreased RGS scores as well as IL-1β, TNF-α, and histological inflammation but had a positive effect on T-SOD levels. Conclusions: LA extract, especially at 250 mg/kg, shows potent anti-inflammatory, analgesic, and antioxidant properties in CIE rats.