Protective Effects of Red Guava on Inflammation and Oxidative Stress in Streptozotocin-Induced Diabetic Mice.

Pei-Ying Li,Che-Yi Chao,Cheng-Chin Hsu,Mei-Chin Yin,Feng-Yao Tang,Yueh-Hsiung Kuo

doi:10.3390/molecules201219831

Abstract

Diabetes is an important chronic disease and the 4th leading cause of death in Taiwan. Hyperglycemia-induced oxidative and inflammatory damage are the main causes of chronic complications in diabetic patients. The red guava (red-fleshed guava cultivar of Psidium guajava L.) is a tropical fruit belonging to the Myrtaceae family and an important commercial crop in Taiwan. In this study, the protective effects of a diet containing red guava on inflammation and oxidative stress in streptozotocin (STZ)-induced diabetic mice were examined. The experimental group was divided into seven subgroups: normal (N), diabetes mellitus (DM), diabetes + red guava 1% (L), 2% (M), and 5% (H), diabetes + 5% red guava + anti-diabetic rosiglitazone (HR), and diabetes + anti-diabetic rosiglitazone (R). The mice were fed for 8 weeks and sacrificed by decapitation. Compared with the DM group, the experimental groups with diets containing red guava as well as rosiglitazone all showed significant improvements in blood glucose control, insulin resistance, creatinine, blood urea nitrogen, triglycerides, non-esterified fatty acids, cholesterol, c-reactive protein, TNF-α, and IL-10. Furthermore, the expression of inflammatory proteins, such as iNOS and NF-κB, was suppressed via activated PPARγ, and the expression levels of GPx3 and ACO increased. In summary, red guava can significantly suppress inflammatory and oxidative damage caused by diabetes and alleviate diabetic symptoms; thus, it exerts protective effects and has potential applications for the development of a dietary supplement.

Highlights

Diabetes is a long-course chronic metabolic disease
After inducing diabetes by continuous STZ injection, except in the diabetes mellitus (DM) group, the blood glucose levels in mice of the L, M, H, HR, and R groups were not statistically different from those of mice in the N group (p > 0.05) after 8 weeks of feeding with experimental diets, suggesting that red guava was beneficial for blood glucose control
The experimental results indicate that the addition of an appropriate amount of red guava in the diet can alleviate hyperglycemia and hyperinsulinemia caused by diabetes

Summary

Introduction

Diabetes is a long-course chronic metabolic disease. In modern society, changes in lifestyle and diet are associated with an increasing incidence of diabetes, and this has become a global health issue. A newer strategy in the treatment of type II diabetes is to reduce insulin resistance in peripheral tissue and control of blood glucose level. According to previous studies [8], guava contains high levels of dietary fiber, which effectively controls blood glucose. The nature of functional molecules in red guava including anthocyanins, flavonoids, proanthocyanins, sesquiterpenoids and triterpenoids of fruit extract. These antioxidant properties are associated with its phenolic compounds such as protocatechuic acid, ferulic acid, quercetin and guavin B, quercetin, ascorbic acid, gallic acid and caffeic acid [9]. Activation of PPAR lowers plasma triglycerides and elevates plasma HDL cholesterol levels, at the same time increasing insulin sensitivity leading to its anti-diabetic effects [12]. Some academic studies have confirmed the glucose stabilization and anti-oxidation effects of red guava, but a detailed mechanism has yet to be elucidated, in this study, the effects of dietary red guava on type II diabetic mice were explored

Results

Discussion

Conclusion