Bangalore Prabhashankar Arathi

Enhanced cytotoxic and apoptosis inducing activity of lycopene oxidation products in different cancer cell lines.

Currently, upon understanding the metabolomics of carotenoids, it is important to address the key role of carotenoid derived products. In this regard, aim of the study was to elucidate and explore the role of lycopene (LYC) oxidative products generated through autoxidation (AOL) or chemical (KMnO4) oxidation (COL) against proliferation of selected cancer cells. Preliminary, we investigated the effect of LYC on cell viability of various cancer cell lines (PC-3, MCF-7, A431, HepG2, HeLa and A549). Based on the results of LYC treatment on cell cytotoxicity levels, MCF-7, PC-3 and HeLa cell lines were further tested with AOL and COL products. The decreased cell viability with depleted GSH and increased MDA levels were observed when treated with COL products than control, LYC and AOL. In addition, COL products increased ROS levels and percent apoptosis. The typical morphological changes and nuclear condensations showed that COL products have anti-proliferation and apoptosis inducing activity. Based on results, we hypothesized that ROS generation by LYC oxidation products may be one of intermediate step involved in apoptosis. The redox status and therapeutic approach of COL products in modulating ROS and induction of apoptosis in cancer cells were reported for the first time, to our knowledge. To conclude, COL products involves in cancer growth inhibition efficiently than intact LYC and AOL. Hence, there is a great potential for synthesizing or producing such carotenoid oxidation products to augment cancer complication.

Biofunctionality of Carotenoid Metabolites: An Insight into Qualitative and Quantitative Analysis

Epidemiological and clinical studies have shown that dietary intake of carotenoid-rich fruits and vegetables is positively correlated with reduction in age-related eye diseases, atherosclerosis, certain cancers and chronic diseases. Carotenoids consist of unique chemical characteristics and are highly vulnerable to structural modifications, leading to the formation of various derivatives under physiological conditions. The identification of these molecules is necessary before addressing their biological functions. Carotenoid metabolomics is believed to be highly complex to fingerprint due to instability and interference with complex biological matrices. Noteworthy, progress has been made in understanding carotenoid metabolism or its biotransformation in biological samples. In this regard, the chapter highlights the concept of metabolomics and their related bio-analytical techniques pertaining to the detection of carotenoids and their derived products to elucidate their bio-transformation on targeted biological functions. Further, this chapter highlights the various hyphenated analytical tools and their optimization.

Concept Notes on Carotenoid Metabolites

Carotenoids are tetraterpenoid consists of series of conjugated double bonds and they are liable to enzymatic or non-enzymatic oxidative breakdown or isomerization at various physiological conditions. Further, oxidation or isomerization can also occur during food processing and other chemical reactions. In general, biotransformation of carotenoids occurs through hydroxylation, epoxidation, isomerization and oxidation-reduction in vivo. Central cleavage of carotenoids gives C20 compounds retinoids, eccentric cleavages gives smaller fragments, notably C10, C13 and C15 compounds with end group. Carotenoids are associated with reduced incidence of major health related problems such as vitamin-A deficiency, age-related macular degeneration, atherosclerosis, cancers and other chronic diseases.