Apigenin targets protein and lipids of HeLa cells and exhibits protective efficacy against oxidative stress

Apigenin, non-toxic and non-mutagenic flavonoid, is an alternative to classical drugs that interact with membranes. Hence, the objects of the study were to examine its effects on liposomes made of egg yolk phosphatidylcholine (EYPC) with the use of 1H NMR, four-electrode BLM and EPR techniques, and determine its activity on lipids and proteins of human cervix carcinoma (HeLa) cells. In addition its protective efficacy against H2O2- induced oxidative shock was investigated. FTIR spectroscopy was applied to study molecular interactions with membrane lipids and proteins of HeLa cells. Microscopic techniques (SEM, light, and fluorescence), flow cytometer analysis, and NR assays were employed to reveal apigenin involvement in apoptosis in different cell conditions. Apigenin affected mainly the region of choline head groups and the hydrophobic core below this area. Simultaneously, the ordering effect was shown. The fingerprint region of lipids in the HeLa cells was found as a target for apigenin. Furthermore, in the amide I and amide II regions, a decrease in β-sheets and an increase in turns, loops, and unordered structures were noted. Apigenin reduced viability of cells and induced apoptosis. SEM observations revealed characteristic changes in morphology of the examined cells. Pretreatment of HeLa cells with apigenin protected them against H2O2-induced oxidative stress by the increase in glutathione content as well as superoxide dismutase and catalase levels. The consequences of molecular changes related to membranes and cancer cells make apigenin a unique and very interesting bio-compound with great significance for medical and biological applications.