R. D. Lele Nuclear Medicine Dept
Jaslok Hospital & Research Centre
India
Abstract:
Carcinogenesis is a multi-step process, the initiation of which can be blocked or suppressed by dietary phytochemicals. They can also halt or retard the progression of pre-cancerous cells into malignant cells.
Non-nutrient phytochemicals exert their substantial antimutagenic and anticarcinogenic properties by blocking cell signalling pathways that regulate cell proliferation & differentiation. One of the central components of the intracellular signalling network that maintain homeostasis is the family of Mitogen-activated protein kinases (MAPKs) (MAPK, NFkB and AP1, NRF2) as well as β catenin, a component of cell-cell adhesion machinery. Extensive work has been done to elucidate the chemo-preventive potential of Haldi (curcumin), Red Chilli pepper (capsaicin) ginger (gingerol), green tea (epigallocatechin) honey (caffeic acid), garlic (diallylsulphide) cabbage (indol-3 carbinol), broccoli (sulphara-phane), carrots (β carotene) grapes (resveratrol).
A novel approach to cancer prevention is transcriptional gene silencing via small interfering RNAs. Nutrigenomics and epigenetics have elucidated how dietary phytochemicals can modify gene expression.
Since the progression of cancer is a multi-step process occuring over years, clinical trials for Chemoprevention of cancer will have to extend over a 10 year period, similar to the Framingham study in USA in the 1950’s. But an ancient Indian insight encourages this approach. Ayurveda the ancient Indian system of Health Care describes Satwik Ahar (diet) and states that Rishis and Munees who took this ahar (Kanda, Moola, Phala- Fruits and vegetables) lived for 100 years. In today’s parlence Satwik ahar (400 gm fruits and vegetable) is a low calorie diet (1300) which gives the least oxidative stress, and provides several anti-oxidants. Excessive free radical generation (through reactive oxygen species- ROS and reactive nitrogen species RNS) is central to DNA damage and carcinogenesis. 12 herbal drugs described in Ayurveda have proven antioxidant effect at various levels - suppress free radical formation, suppress chain initiation and break chain propagation, reconstitute cell membrane and repair DNA damage. (Fig. 1).
Ref.: R. D. Lele Ayurveda & Modern Medicine 2nd ed. 2001. Bharatiya Vidya Bhavan, Mumbai.
Keywords: Carcinogenesis- multi-step process, Dietary phyochemicals capable of blocking or suppressing progression via MAPK, NFKB, AP-1, NRF2 β catenin.. Nutrigenomics and epigenetic gene silencing.
Anti-oxidants prevent DNA damage.
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