Department of Health and Nutrition Biotechnology, Asia University, Taichung, Taiwan.
Food Chem Toxicol. 2011 Sep;49(9):2189-95. doi: 10.1016/j.fct.2011.05.032. Epub 2011 Jun 7.
Psidium guajava Linn. (family Myrtaceae; PG) is a tropical fruit with a blood-glucose-lowering effect in diabetic rats, but its mechanism of action is still unknown. We investigated the antihyperglycemic efficacy and mechanisms of action of PG in streptozotocin (STZ)-induced diabetic rats. After 4 weeks of PG supplementation (125 and 250 mg/kg), PG significantly restored the loss of body weight caused by STZ and reduced blood glucose levels in a dose-dependent manner compared with that in diabetic control rats. Mechanistically, PG protected pancreatic tissues, including islet β-cells, against lipid peroxidation and DNA strand breaks induced by STZ, and thus reduced the loss of insulin-positive β-cells and insulin secretion. Moreover, PG also markedly inhibited pancreatic nuclear factor-kappa B protein expression induced by STZ and restored the activities of antioxidant enzymes, including superoxide dismutase, catalase, and glutathione peroxidase. We conclude that PG has a significant antihyperglycemic effect, and that this effect is associated with its antioxidative activity.
番石榴（桃金娘科；PG）是一种热带水果，具有降低糖尿病大鼠血糖的作用，但作用机制尚不清楚。我们研究了番石榴在链脲佐菌素（STZ）诱导的糖尿病大鼠中的降血糖作用及其作用机制。在 PG 补充 4 周后（125 和 250mg/kg），PG 可显著恢复 STZ 引起的体重减轻，并呈剂量依赖性降低血糖水平，与糖尿病对照组大鼠相比。在机制上，PG 可保护胰岛β细胞等胰腺组织免受 STZ 诱导的脂质过氧化和 DNA 链断裂，从而减少胰岛素阳性β细胞的丢失和胰岛素分泌。此外，PG 还可显著抑制 STZ 诱导的胰腺核因子-κB 蛋白表达，并恢复超氧化物歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶等抗氧化酶的活性。我们得出结论，PG 具有显著的降血糖作用，这种作用与其抗氧化活性有关。
