Antioxidant effects of Camellia sinensis L. extract in patients with type 2 diabetes

Abstract

The prevalence of diabetes mellitus (DM) has dramatically increased in the past decade. Furthermore, increasing evidence from research shows that oxidative stress (OS) plays a crucial role in the pathogenesis of diabetes and in its complications. A search for ways to reduce oxidative damage has become the focus of interest for the majority of scientists. In this study, we determined the radical scavenging activity of single green tea constituents by using an on-line high performance liquid chromatography (HPLC)-2,2-diphenyl-1-picrylhydrazyl (DPPH) method and evaluated the antioxidant effects on type 2 diabetic patients by performing a double-blind, placebo-controlled study. Epigallocatechin gallate was identified as the most potent antioxidant, contributing approximately 50% of the total antioxidant capacity of green tea extract. We also found a statistically significant decrement of lipid peroxidation markers in patients treated with green tea extract after 9 months or after 18 months of follow-up. Overall, these findings are attractive for diabetic patients, helping them to keep a high level of performance and well-being, which ultimately may delay the time of disability and reduce mortality.

Antidiabetic Effects of Tea

“…There are many bioactive components in tea showing antioxidant activity, including catechins [ 23 ], gallic acid [ 44 ] and polysaccharides [ 45 ]. EGCG, the most abundant catechin compound, is a potent antioxidant in GTE [ 46 ]. Tea polysaccharides are another group of antioxidants in tea, and their antioxidant activities depend on monosaccharide composition and molecular weight [ 47 ].…”

Antioxidant Activity of Methanol Extract from Several Indonesian Green Teas

“…This result indicated that antioxidant compounds in the extracts are significantly able to reduce DPPH radical into its nonradical form DPPH-H. Therefore, our results suggested that tea extracts may be a promising source of antioxidant which may protect against diseases induced by radicals (Patlevič et al, 2016, Spadiene et al, 2014. Recent studies have highlighted the importance of polyphenolic compounds due to their importance in antioxidant activities and other biological activities (Makris et al, 2007).…”

Citric acid‐enhanced dissolution of polyphenols during soaking of different teas

“…Previous studies suggest that EGCG, EGC, ECG, EC, and C are the major catechins in tea, with their antioxidant activities demonstrated in the following order: EGCG > ECG > EGC > EC > C (Li et al, ; Spadiene et al, ). It is widely recognized that polyphenols of different molecular structures present different antioxidant activities.…”