一种葡萄柚中常见的黄酮类化合物,具有抗氧化、自由基清除剂、抗炎化合物、碳水化合物代谢促进剂和免疫系统调节剂的作用。
Naringenin is a flavonoid commonly found in grapefruits which functions as an antioxidant, free radical scavenger, anti-inflammatory compound, carbohydrate metabolism promoter, and immune system modulator. Studies indicate that in vitro Naringenin reduces oxidative damage to DNA. In addition, Naringenin potently inhibits the secretion of very-low-density lipoproteins by cells. Furthermore, Naringenin has been shown to reduce cholesterol concentrations in hepatocytes and plasma cells via inhibiting HMGCR (HMG-CoA reductase). Studies conducted on Hepatitis C virus particles demonstrate that Naringenin can inhibit the virus via a PPAR-mediated mechanism by inhibiting the long term assembly of the virus.
Naringenin is shown to inhibit the proliferation of HepG2 cells resulted partly from an accumulation of cells in the G0/G1 and G2/M phase of the cell cycle. Naringenin has been shown to induce apoptosis as evidenced by nuclei damage and increased proportion of apoptotic cells. Naringenin triggers the mitochondrial-mediated apoptosis pathway as shown by an increased ratio of Bax/Bcl-2, subsequent release of cytochrome C, and sequential activation of caspase-3. Naringenin exposure significantly reduces the cell viability of A431 cells with a concomitant increase in nuclear condensation and DNA fragmentation in a dose dependent manner. Cell cycle study shows that naringenin induced cell cycle arrest in G0/G1 phase of cell cycle and caspase-3 analysis reveal a dose dependent increment in caspase-3 activity which leads to cell apoptosis.
体内研究:
Naringenin supplementation causes a significant reduction in the amount of total triglyceride and cholesterol in plasma and liver. In addition, naringenin supplementation lowers adiposity and triglyceride contents in parametrial adipose tissue. Naringenin-fed animals show a significant increase in PPARα protein expression in the liver. The expression of CPT-1 and UCP2, known to be regulated by PPARα, is markedly enhanced by naringenin treatment. Naringenin increases hepatic fatty acid oxidation through a PPARγ coactivator 1α/PPARα-mediated transcription program. It prevents sterol regulatory element-binding protein 1c–mediated lipogenesis in both liver and muscle by reducing fasting hyperinsulinemia. Naringenin decreases hepatic cholesterol and cholesterol ester synthesis. Naringenin inhibits TNF-α-induced VSMC proliferation and migration in a dose-dependent manner. Mechanistic study demonstrates that naringenin prevents ERK/MAPK and Akt phosphorylation while left p38 MAPK and JNK unchanged. Naringenin also blocks the increase of ROS generation induced by TNF-α.