“…With the higher number of hydroxyl groups, the tendency of chain breaking antioxidant behavior of the compound increases [20].Phenolic is found in abundant in plants which is the major secondary metabolites of plants, serving in plan defense mechanism for counteracting reactive oxygen species (ROS) [21,22].In cacti, red-violet betacyanin's and yellow betaxanthins are the most important fruit pigments, belonging to betalain pigments [23].Betalain is a class of water-soluble pigments that provide the colors in a wide ranging of flowers and fruits [24].Moreover, betacyanin's that are attached to n-heterocyclic compounds are a class of compounds that can also employed as antioxidants, with radical scavenging activities. Antioxidant activity of dragon fruit is mainly due to the content of ascorbic acid (vitamin C) [26].In living organisms, ascorbic acid serves in many physiological functions, such as acts reductant to prevent cellular components from oxidative damage [27].This is because ascorbic acid has the capability of serving as a scavenger in the oxidation of free radicals and oxygen-derived species, e.g., singlet oxygen, hydrogen peroxide and hydroxyl radicals [28].Hence, ascorbic acid is found to be very useful in the treatment of photo-aging [29].Instead, pro-oxidant properties of ascorbic acid also contribute to its antibacterial effects [30].In the human body, the formation of free radicals is regulated by various enzymes and antioxidants in response to exogenous stimuli. In the case of extensive production of free radicals, it could lead to traumatic injury, inflammation and other chronic events, such as cancer and degenerative disease, due to the oxidant stress [31].Over last few decades, few antioxidant vitamins which have the ability of limiting oxidative damage, have been introduced such as beta-carotene, vitamin C and vitamin E, thus minimizing the threats of particular chronic disease [32].This can be observed from the closely association of heart diseases and low plasma levels of beta-carotene, tocopherol and L-ascorbic acid in epidemiological studies [33].…”