No abstract

Cassia fistula L., a semi-wild Indian Labernum, is widely cultivated in Mauritius as an ornamental tree for its beautiful bunches of yellow flowers and also used in traditional medicine for several indications. The total phenolic, proanthocyanidin, and flavonoid contents, and the antioxidant activities, of fresh vegetative and reproductive organs of Cassia fistula harvested at different stages of growth were determined using the Trolox equivalent antioxidant capacity (TEAC) and ferric-reducing antioxidant power (FRAP) assays. The antioxidant activities were strongly correlated with total phenols (TEAC r = 0.989; FRAP r = 0.951) in all organs studied, and with proanthocyanidins (TEAC r = 0.980; FRAP r = 0.899) in reproductive organs including fruits. The antioxidant activities of reproductive parts were higher than those of the vegetative organs, with the pods having highest total phenolic, proanthocyanidin, and flavonoid contents and antioxidant potentials (TEAC = 992 +/- 0.4 micromol/g dry weight; FRAP = 811 +/- 23 micromol/g dry weight).

Oxidative stress and associated mechanisms involving inflammation, aberrant signaling pathways and gap junction intercellular communication is increasingly associated with the pathogenesis of various chronic degenerative disorders such as atherosclerosis, neurodegeneration and cancer. Consumption of fruits, vegetables and beverages like teas continues to be suggested to have the capacity to reduce the incidence of cancer. The bioactive compounds including phenolics may be responsible for the chemopreventive effects. While the free radical scavenging and antioxidant properties of phenolics are well established, emerging literature reports suggest that their chemopreventive effects may also be ascribed to their ability to modulate components of cell signaling pathways. This paper reviews the potential chemoprevention role of phenolics with a focus on cellular signal transduction mechanisms and prevention of gap junction intercellular communication relevant to cancer.

Current hypotheses favour the concept that lowering oxidative stress can have a health benefit. Free radicals can be overproduced or the natural antioxidant system defenses weakened, first resulting in oxidative stress, and then leading to oxidative injury and disease. Cardiovascular disease is one example of this process. This disorder continues to be the major cause of premature death worldwide. Oxidation of human low-density lipoproteins is considered an early step in the progression and eventual development of atherosclerosis, one of the leading causes to cardiovascular dysfunction. Compelling support for the involvement of free radicals in disease development originates from epidemiological studies showing that an enhanced antioxidant status is associated with reduced risk of several diseases. Dietary nutraceuticals such as vitamins C, E and polyphenolics and reduction of cardiovascular disease incidence are a notable example. This paper reviews the biology of ROS/RNS, their pathways through which they relate to the pathology of cardiovascular disease and discusses the putative roles that antioxidants, including phenolics, may play in controlling oxidative stress and reduce the incidence of cardiovascular disease.