Pre-exposure to a novel nutritional mixture containing a series of phytochemicals prevents acetaminophen-induced programmed and unprogrammed cell deaths by enhancing BCL-XL expression and minimizing oxidative stress in the liver

Abstract

From a disease-prevention perspective, recent progress in phytochemical and nutraceutical research clearly suggests (benefits outweigh the risk pattern). Although powerful antioxidant properties have been the most acclaimed mechanism of action for these entities, the individual antioxidants studied in clinical trials do not appear to have consistent preventative effects. The actions of the antioxidant nutrients alone do not explain the observed health benefits of diets rich in fruits and vegetables for chronic diseases. Therefore, we proposed that the additive and synergistic effects of phytochemicals in fruits and vegetables are responsible for these potent antioxidant and anticancer activities, and that the benefit of a diet rich in fruits and vegetables is attributed to the complex mixture of phytochemicals present in plants [1]. Surprisingly, however, no studies have attempted to evaluate the combined antitoxic potential of a phytochemical-nutraceutical mixture (PNM) in in vivo models. Therefore, this study, for the first time, was designed to investigate whether pre-exposure to a unique PNM has the ability to impede mechanistic events involved in acetaminophen (APAP)-induced hepatotoxicity. Besides several vitamins and minerals in balanced proportions (~US RDA), the PNM used in this investigation contained several well-known phytochemicals such as citrus flavonoids, red wine polyphenols, Garcinia, Gymnema, Ginkgo, Ephedra sinica, Camelia sinensis, Silybum, Guarana, Eluthero, Allium sativum and Ocimum basilicum extracts. To evaluate PNM's antitoxic potential, groups of animals ICR mice, 3 months old) received either a control diet or PNM containing diets (1X and 10X) for 4 weeks. On day-28, animals were divided into two subgroups. Half the animals were administered normal saline and the other half received 400mg/kg ip injections of APAP. All the animals were sacrificed 24h after APAP exposure. Serum and tissue (liver and kidneys) samples were analyzed. APAP alone caused massive liver injury (nearly 495-fold increase in ALT) and oxidative stress (Lipid peroxidation: 268% increase in MDA) coupled with genomic DNA fragmentation (288% increase). Exposure to 1X-PNM for 28 days significantly reduced animal mortality and all the APAP-induced biochemical events (In 1X-PNM + AP: ALT leakage decreased to 54 fold; MDA accumulation decreased to 125%, and DNA fragmentation decreased to 122%), whereas 10X-PNM + APAP slightly escalated both oxidative stress and genomic DNA fragmentation preceding liver injury. Liver homogenates subjected to western blot analysis disclosed the ability of 1X-PNM to counteract APAP-induced decrease in Bcl-xL expression. Histopathological evaluation of stained liver tissue sections indicated anti-apoptogenic and anti-necrogenic reponses coupled with near complete prevention of glycogen depletion by 1X-PNM. Collectively, our investigation suggests that a mixture containing an assortment of phytochemicals/nutraceuticals may serve as a much more powerful blend in preventing drug or chemical-induced organ injuries than a single phytochemical or nutraceutical entity. In addition, ephedra and caffeine containing PNM-exposure in a controlled manner may potentially shield vital target organs from toxicities caused by intentional, unintentional or accidental exposures to structurally and functionally diverse drug and chemical entities.