Plasma protein affinity, antioxidant, and anti-lung cancer properties of O-methylated flavonol rhamnazin

Medicinal herbs can be used for the development of antioxidant and anticancer platforms. However, the mechanisms by which the bioactive materials show these properties remain largely unclear. Also, a detailed understanding of the interaction between small compounds and carrier proteins like albumin can provide useful information about the regulation of their stability and circulation time properties. In this paper, the interaction of rhamnazin (C17H14O7), an O-methylated flavonol exists in Rhamnus petiolaris, with human serum albumin (HSA) was investigated. Also, the antioxidant and anti-lung cancer effects of rhamnazin were assessed. The results showed that a static rhamnazin-HSA complex was formed by the contribution of hydrophobic forces, which led to an increase in the content of the α-helix structure of HSA. Cellular assays revealed that rhamnazin (10 µM) recovered cell viability in human proximal renal tubular epithelial cells (HK2) reduced by H2O2 (0.5 mM) through reduction of ROS, restoration of CAT and SOD activities and GSH content, regulation of Bax, Bcl-2, and caspase-3. Moreover, the anti-lung cancer data demonstrated that rhamnazin induced apoptosis on lung adenocarcinoma A549 cells associated with a p53-dependent manner via overexpression of apoptotic Bax and caspase-3 and down-regulation of anti-apoptotic Bcl-2. To summarize, the potential binding of rhamnazin and HSA, as well as its antioxidant/anticancer properties, are critical for understanding the solubility and stability of this bioactive compound in plasma, as well as its therapeutic implications.