The term ROS includes superoxide, hydrogen peroxide, hydroxyl radical, nitric oxide and peroxynitrite. Collectively, they are also referred to as free radicals. In excess, they contribute to a host of chronic and age-related disorders. ROS can be extinguished by antioxidants which function to restore physiological equilibrium (homeostasis). Therefore, to boost the aging process, excessive ROS must be eliminated. One way this may be achieved is by regulating the NADPH oxidase (NOX) system: the system that generates ROS. Older adults are more prone excessive accumulation of ROS (aka: oxidative stress) due to a slow-down of antioxidant generation. Because they produce high levels of ROS, the heart and brain, with high oxygen consumption, are especially susceptible. Typically, an inverse relationship exists between high blood antioxidant concentrations and the onset and progression of diseases including cardiovascular diseases and cancer. To rephrase, the higher the level of antioxidants the lower the incidence of these diseases. Yet, the presence of ROS per se is not deleterious. At physiological concentrations ROS regulate a myriad of cellular processes. In humans and other animals, physiological ROS regulate DNA and cell signaling. Moreover, cellular activities such as cell survival, adrenaline release, inflammation and infections are influenced by ROS. 
Dietary antioxidants and longevity
Undoubtedly, high circulating ROS cause cellular damage. And, cellular injury accelerates aging and the progression of age-related diseases. In fact, a buildup of ROS triggers a host of chronic aging diseases. Among them are arthritis, type II diabetes, cancer, cardiovascular diseases, obesity, osteoporosis and neurodegenerative disorders: namely, dementia, Parkinson’s and Alzheimer’s diseases (AD). But there is hope. Natural antioxidants offsets excess free radical (oxidative stress), improve immune function and increase healthy longevity. In part, this is achieved by disrupting free radical propagation and/or inhibiting the formation of free radicals. Antioxidants are capable of quenching the ROS (hydroxyl or hydroperoxyl radicals) that initiate peroxidation of cell membrane lipids. They disrupt the oxidative process and neutralize free radicals. As a result, dietary antioxidants have received considerable attention as therapeutic agents accelerated aging. Accordingly, lowering ROS levels in the body retards aging, increases lifespan, and prevents age-associated diseases.
Of the high antioxidant therapeutic candidates, resveratrol and curcumin show enormous potential. They are being evaluated for treating cognitive dysfunction in aging and AD. After a 4-months dietary regimen on resveratrol, middle-aged men with metabolic syndrome showed marked improvement. Subjects showed increased muscle turnover and lipid metabolism. Regarding the latter, resveratrol-treated subjects showed an accumulation of long-chain saturated, monounsaturated and polyunsaturated free fatty acids. Another trial revealed that resveratrol reduced blood pressure to normal levels in hypertensive subjects. No side-effects were reported. Other clinical trials have shown that resveratrol treatment improved memory performance in healthy overweight elderly individuals and patients with type 2 diabetes. Amyloid β is central to the formation of amyloid plaques found in the brains of people with Alzheimer’s disease. According to research data, resveratrol treatment decreased amyloid β levels in both plasma and cerebrospinal fluid in individuals with mild to a moderate AD.
In clinical trials of healthy elderly subjects, curcumin was found to improve attention span, working memory, mood and fatigue. Studies also reveal that daily oral ingestion of curcumin augmented memory performance over 18-months in normal middle-aged and older adults. Also, daily oral consumption of curcumin led to less amyloid β plaques in the brain. Both curcumin and resveratrol have been reported to be safe and well-tolerated.
Herbs in Traditional Chinese Medicine
In Traditional Chinese Medicine (TCM) several herbal products have been touted as potential promoters of healthy longevity. Among them is Astragalus membranaceus (Huangqi). It is touted as a robust antiaging drug. Astragalus has been a prime ingredient in TCM herbal formulations. It is also lauded as a life-extending tonic for humans. Among the active ingredients of Astragalus membranaceus are polysaccharides, flavonoids, and saponins. These components have been shown to potentiate antioxidant effects. Other properties attributed to them anti-inflammatory, immunoregulatory, anticancer, hypolipidemic, anti-hyperglycemic, hepatoprotective and diuretic. An extract of the dried roots, reportedly boost immune responses. In view of its putative health benefits, Astragalus membranaceus may be suitable dietary candidate for investigation against vascular aging, brain aging, cancer and age-related diseases.
 Homeostasis: Resistance to change to ensure a stable internal environment. It involves feedback loops that offset changes in preset values.