Novel chemotherapeutic and renal protective effects for the green tea (EGCG): role of oxidative stress and inflammatory-cytokine signaling.

BACKGROUND: The green tea catechin, epigallocatechin-gallate (EGCG) is a superb nature's medicine candidate. We evaluated the chemotherapeutic/chemoenhancing effects of EGCG in mice bearing the solid Ehrlich ascites carcinoma (EAC) tumor, and jointly monitored levels of serum C-reactive protein (CRP), lipid peroxidation (as malondialdehyde: MDA) and leukocytosis (LC). Besides, we verified whether; and how then, EGCG would protect against a devastating CP-induced nephrotoxicity in rats. In particular, renal proinflammatory (TNF-α) and oxidant stress signals have been investigated. RESULTS: (EAC)-bearing mice displayed elevated serum-LC (2-fold), -CRP (11-fold) and -MDA levels (2.7-fold). EGCG (20, 40 mg/kg) significantly shrank tumors (by 48% and 92%, respectively), and reduced LC, CRP and MDA levels. Such responses for CP were less prominent than those of EGCG (40 mg/kg). Further, EGCG (20 mg/kg) markedly augmented such functional and biochemical responses to CP. Correlation studies showed positive association between tumor size and each of CRP (r=0.97) and LC (r=0.83). Additionally; in rats, CP (10 mg/kg) caused a prominent nephrotoxicity that was manifested as deteriorated glomerular filtration rate (GFR, 2-5-fold rise in serum creatinine/urea levels) after 4 days, and unanimous animal fatalities after 7 days. Kidney homogenates from CP-treated rats showed significantly higher MDA- and TNF-α-, and -depleted GSH levels. Rats treated with EGCG (50 mg/kg, but not 25 mg/kg) devoid the nephrotoxic effects of CP and their consequences; while their homogenates had appreciably lower MDA and TNF-α, and higher GSH levels. Notable correlation was detected between serum creatinine level and each of MDA (r=0.85), TNF-α (r=0.85) and GSH (r=-0.81). CONCLUSION: This study shows remarkable cytotoxic/chemoenhancing effects for EGCG and introduces CRP as a predictor of both tumor's progression and responsiveness to chemotherapy. Further, this study is the first to reveal that EGCG can obliterate the lethal CP-induced nephrotoxicity. Mechanistically, EGCG acts by suppressing leukocytosis, systemic inflammation, oxidative stress, and their sequelae.

Prominent chemopreventive and chemoenhancing effects for resveratrol: unraveling molecular targets and the role of C-reactive protein.

BACKGROUND: Resveratrol (RSVL) claims health benefits that pertain to the consumption of red wine/grapes. We currently evaluated the chemopreventive effects of RSVL, as well as its possible chemoenhancing effects when given with cisplatin (CP), in the Ehrlich ascites carcinoma (EAC) solid tumor model. Further, we monitored concomitant changes in serum levels of C-reactive protein (CRP), tumor necrosis factor-alpha (TNF-alpha), leukocytic count (LC) and lipid peroxidation (measured as malondialdehyde, MDA). RESULTS: EAC-bearing mice exhibited a markedly elevated LC (2 fold), CRP (11 fold) and MDA levels (2.7 fold). RSVL (20 or 40 mg/kg) elicited significant, dose-dependent reductions in tumor size (58 and 78%, respectively), as well as in LC (normalized), CRP (down to 2 fold), TNF-alpha (down to near control levels) and MDA levels (normalized). The chemopreventive effects for CP (55% reduction in cell growth) was significantly lower than that of RSVL (40 mg/kg, 79% inhibition). Interestingly, coadministration of RSVL (20 mg/kg) markedly enhanced the chemoprevention of CP. Correlation studies revealed a high degree of positive association between tumor growth and CRP (r = 0.89) and leukocytosis (r = 0.86), thus attesting to a diagnostic/prognostic role for CRP in this solid tumor. CONCLUSION: RSVL elicited remarkable cytotoxicity on its own and appreciably augmented those of CP as well. The extent of tumor progression in various mouse groups was highly reflected by CRP levels. RSVL acts prominently by reducing inflammatory cytokines, leukocytosis and oxidative stress.