Antioxidants, naturally occurring plants

Naturally occurring compounds such as phytochemicals, which possess anticar-cinogenic and other beneficial properties, are referred to as chemopreventers. One of the predominant mechanisms of their protective action is due to their antioxidant activity and the capacity to scavenge free radicals. Among the most investigated chemopreventers are some vitamins, plant polyphenols, and pigments such as carotenoids, chlorophylls, flavonoids, and betalains. Resolution of the potential protective roles of... 

Naturally occurring antioxidants are present in many plants and trees such as hevea rubber. The first synthetic antioxidants were synthesized independently by Caldwell and by Winkelman and Gray by the condensation of aromatic amines with aliphatic aldehydes. 

Tocopherols (2) are the major class of natural or nature-identical antioxidants. They occur naturally in many plant tissues, particularly... 

There is a growing interest in naturally occurring phenolic compounds that display biological antioxidant properties such as -hydroxycinnamic acid, ferulic zcid, caffeic acid/ and curcumin which are ubiquitous in plant food. It has been demonstrated that the interaction of the oxidizing OH adduct of DNA, poly-A and poly-G with hydrox-ycinnamic acid derivatives proceed via electron transfer. Cinnamic acid derivatives have been shown to be able to scavenge superoxide, peroxyl, and hydroxyl radicals. 

Use of plant parts (bark, leaves, seeds, etc.) and their extracts to preserve food from developing a rancid taste is a practice that has continued since prehistoric time. There is evidence that even for the industrial materials, plant-based components were used as antidrying agents to prevent oxidation and polymerization of polyunsaturated fatty acid-rich plant oils (2, 5, 48). During the past two decades, intensive research has been carried out on naturally occurring antioxidative compounds from different sources. The main drive behind this search was to reduce the use of synthetic compounds as food additives because of their potential negative health effects and as a result of consumer demand. 

Ascorbic acid and tocopherols are the most important commercial natural antioxidants. In addition, many naturally occurring phenolic antioxidants have been identified in plant sources and vegetable extracts that may lend themselves for use in a variety of food applications (53). Recent research has focused on isolation and identification of effective antioxidants of natural origin (11). 

ABSTRACT More than 200 naturally occurring oligostilbenes isolated from plant kingdom are grouped into I-V structural types. They are a special kind of polyphenolic natural products with multi-faceted bioactivities. This article will review their classification, distribution, spectral characteristics, biological activities (anti-fungal, antibacterial, antioxidant, anti-inflammatory and anticarcinogenic activities, etc.) and mimetic biosynthesis. 

Phytochemicals are bioactive natural antioxidants which occur in different fruits and vegetables [26], These plant-derived antioxidants are defined as chemicals with health -promoting effects which derive fi om plants, but cannot be considered human essential nutrients [31], Due to the complexity of some plant-derived antioxidants, there is limited information about the health-promoting effects of these compounds [32], However, major groups of natural antioxidants are carotenoids, flavonoids, alkaloids, etc. [33],... 

Documented effects The alkaloid spherophysine, which was isolated from the aboveground plant parts, has hypotensive activity and effects uterine action. In the form of a benzoic-acid salt, it is used for essential hypertension of the first and second degrees. Spherophysine is used for arterial hypertension, weak birthing activity (labor difficulties), and post natal bleeding (Sokolov and Zamotaev 1989). A stilbene isolated from the plant was synthesized and tested for antioxidant activity and showed superior antioxidative activity when compared to the well-known antioxidants resveratrol, vitamin C and butylated hydroxyanisole (BHA) (Venkateswarlu et al. 2003). Additionally, synthesized stilbenes based on naturally occurring compounds were active against leukemia and lymphoma cell lines (Tolomeo et al. 2005). 

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