Inhibitory effect of tea polyphenols on hepatic preneoplastic foci in Wistar rats

Amelioration of oxidative stress, inflammation and liver function by nutraceuticals in rat model of hepatic cancer initiation induced by N-nitrosodiethylamine

Introduction: Nutraceuticals might serve as protective agent against liver cancer induced by pro-cancerous chemicals that initiate high oxidative stress, inflammation and affect DNA integrity. The aim of the present research was to study the prevention of hepatocellular carcinoma initiation induced by N-nitrosodiethylamine (NDEA) through treatment by nutraceuticals. Methods: Two nutraceuticals were prepared; the first (NI) was a mixture of different extracts of green tea, wheat germ and tomato, the second one (NII) was composed of extracts mixture of broccoli, hazelnuts and carrot. Total flavonoids and flavonols were determined in the nutraceuticals. Four groups of rats were run; the first served as control normal, the other three groups were treated by intraperitoneal injection of NDEA, one of these groups was designated as control NDEA, the other two groups (test groups) were treated daily with oral doses of NI and NII, respectively. The experiment continued for 8 weeks. Plasma transaminases, alkaline phosphatase and catalase activities, total protein, albumin, malondialdehyde (MDA) and tumor necrosis factor-α (TNF-α) along with liver MDA level and catalase activity were assessed. Results: NI showed higher flavonoids and lower flavonols than NII (P < 0.05). High oxidative stress and inflammation biomarkers, liver dysfunction, reduced plasma albumin and total protein were demonstrated in control NDEA compared to control normal (P < 0.05). Test groups showed significant improvement in all parameters (P < 0.05) compared to NDEA control. NI was superior in improving plasma transaminases and catalase activities, MDA and TNF-α levels and liver catalase activity compared to NII (P < 0.05). Conclusion: Both NI and NII might prevent liver cancer initiation during exposure to carcinogenic agents, NI being superior to NII.

Tea consumption and mortality of all cancers, CVD and all causes: a meta-analysis of eighteen prospective cohort studies

Epidemiological studies have demonstrated inconsistent associations between tea consumption and mortality of all cancers, CVD and all causes. To obtain quantitative overall estimates, we conducted a dose-response meta-analysis of prospective cohort studies. A literature search in PubMed and Embase up to April 2015 was conducted for all relevant papers published. Random-effects models were used to calculate pooled relative risks (RR) with 95 % CI. In eighteen prospective studies, there were 12 221, 11 306 and 55 528 deaths from all cancers, CVD and all causes, respectively. For all cancer mortality, the summary RR for the highest v. lowest category of green tea and black tea consumption were 1·06 (95 % CI 0·98, 1·15) and 0·79 (95 % CI 0·65, 0·97), respectively. For CVD mortality, the summary RR for the highest v. lowest category of green tea and black tea consumption were 0·67 (95 % CI 0·46, 0·96) and 0·88 (95 % CI 0·77, 1·01), respectively. For all-cause mortality, the summary RR for the highest v. lowest category of green tea and black tea consumption were 0·80 (95 % CI 0·68, 0·93) and 0·90 (95 % CI 0·83, 0·98), respectively. The dose-response analysis indicated that one cup per d increment of green tea consumption was associated with 5 % lower risk of CVD mortality and with 4 % lower risk of all-cause mortality. Green tea consumption was significantly inversely associated with CVD and all-cause mortality, whereas black tea consumption was significantly inversely associated with all cancer and all-cause mortality.