Tea is prepared from the young leaves, buds, stalks of the plant Camellia sinensis. The cultivation process of tea plants and the habit of tea drinking were initiated in China from ancient times. Now, the consumption of tea is very popular throughout the world and it is an integral part of our social culture. Tea contains polyphenolic compounds (catechins and epicatechins), theaflavins, flavonol glycosides, L-theanine, caffeine, theobromine, and volatile organic substances. These bioactive components are responsible for the astringency, flavor, aroma, and taste of the tea as well as its health beneficial effects. Moreover, tea has several medicinal values. The phytochemical components are involved in the prevention and cure of many illnesses like cardiovascular diseases, malignancy, digestive dysfunction, and metabolic disorders like obesity, diabetes. Tea flavonoids show strong antioxidant properties. Caffeine and other methylxanthine regulate the intracellular second messenger levels. Additionally, catechins exhibit anti-inflammatory effects. All these multidimensional actions make some positive attributes in favor of neuroprotection, cardioprotection, and cancer prevention. Various approaches are also taken to use tea ingredients as an adjuvant in cancer therapy. This review emphasizes the importance of bioactive components, and their health promotional activities.

The pineal gland is a interface between light-dark cycle and shows neuro-endocrine functions. Melatonin is the primary hormone of pineal gland, secreted at night. The night-time melatonin peak regulates the physiological functions at dark. Melatonin has several unique features as it synchronises internal rhythm with daily and seasonal variations, regulates circadian rhythm and sleep-wake cycle. Physiologically melatonin involves in detoxification of free radicals, immune functions, neuro-protection, oncostatic effects, cardiovascular functions, reproduction, and foetal development. The precise functions of melatonin are exhibited by specific receptors. In relation to pathophysiology, impaired melatonin secretion promotes sleep disorder, cancer progression, type-2 diabetes, and neurodegenerative diseases. Several reports have highlighted the therapeutic benefits of melatonin specially related to cancer protection, sleep disorder, psychiatric disorders, and jet lag problems. This review will touch the most of the area of melatonin-oriented health impacts and its therapeutic aspects.

Carbon tetrachloride (CCl4), a hepatotoxic agent is widely used to study the toxic mechanisms in experimental animals. This study was carried out to establish the hepatoprotective measures of food preservative antioxidants butylated hydroxyanisole and butylated hydroxytolune (BHA, BHT) when mixed with food towards carbon tetrachloride (CCl4) intoxication (230 mg/ kg b wt/rat/day) in rat. Biochemical markers like serum glutamate pyruvate tranaminase (AST), serum glutamate oxaloacetate transaminase (ALT), alkaline phosphatase (ALP) and bilirubin content, antioxidant enzymes such as SOD, CAT, GPx, and malondialdehyde (MDA) as the end product of lipid peroxidanion were measured. The results had shown the elevated level of AST (121.16%), ALT (124.68%), ALP (122.41%) an, bilirubin content (57.14%) after CCl4 treatment. Marked decrease of activity of antioxidant enzymes such as SOD (85.36%), CAT (67.47%), GPx (50.7%) had indicated that the ROS mediated toxicity and pretreatment of BHA and BHT restored the activity of these enzymes. High level of MDA content with reduced GSH value was also observed due to oxidative stress. The hepatic antioxidant status was restored with the food preservative (BHA, BHT) antioxidant treatment which had indicated the significant protective effect against CCl4 induced hepatotoxicity and finally confirmed by histopathological studies.

Neurodegenerative diseases are a serious problem throughout the world. There are several causes of neurodegenerative diseases; these include genetic predisposition, accumulation of misfolded proteins, oxidative stress, neuroinflammation, and excitotoxicity. Oxidative stress increases the production of reactive oxygen species (ROS) that advance lipid peroxidation, DNA damage, and neuroinflammation. The cellular antioxidant system (superoxide dismutase, catalase, peroxidase, and reduced glutathione) plays a crucial role in scavenging free radicals. An imbalance in the defensive actions of antioxidants and overproduction of ROS intensify neurodegeneration. The formation of misfolded proteins, glutamate toxicity, oxidative stress, and cytokine imbalance promote the pathogenesis of Alzheimer's disease, Parkinson's disease, Huntington's disease, and amyotrophic lateral sclerosis. Antioxidants are now attractive molecules to fight against neurodegeneration. Certain vitamins (A, E, C) and polyphenolic compounds (flavonoids) show excellent antioxidant properties. Diet is the major source of antioxidants. However, diet medicinal herbs are also rich sources of numerous flavonoids. Antioxidants prevent ROS-mediated neuronal degeneration in post-oxidative stress conditions. The present review is focused on the pathogenesis of neurodegenerative diseases and the protective role of antioxidants. KEY TEACHING POINTSThis review shows that multiple factors are directly or indirectly associated with the pathogenesis of neurodegenerative diseases.Failure to cellular antioxidant capacity increases oxidative stress that intensifies neuroinflammation and disease progression.Different vitamins, carotenoids, and flavonoids, having antioxidant capacity, can be considered protective agents.