Anticancer Potential of Dietary Natural Products: A Comprehensive Review

Nature is a rich source of natural drug-like compounds with minimal side effects. Phytochemicals better known as "Natural Products" are found abundantly in a number of plants. Since time immemorial, spices have been widely used in Indian cuisine as flavoring and coloring agents. Most of these spices and condiments are derived from various biodiversity hotspots in India (which contribute 75% of global spice production) and form the crux of India's multidiverse and multicultural cuisine. Apart from their aroma, flavor and taste, these spices and condiments are known to possess several medicinal properties also. Most of these spices are mentioned in the Ayurveda, the indigenous system of medicine. The antimicrobial, antioxidant, antiproliferative, antihypertensive and antidiabetic properties of several of these natural products are well documented in Ayurveda. These phytoconstituemts are known to act as functional immunoboosters, immunomodulators as well as anti-inflammatory agents. As anticancer agents, their mechanistic action involves cancer cell death via induction of apoptosis, necrosis and autophagy. The present review provides a comprehensive and collective update on the potential of 66 commonly used spices as well as their bioactive constituents as anticancer agents. The review also provides an in-depth update of all major in vitro, in vivo, clinical and pharmacological studies done on these spices with special emphasis on the potential of these spices and their bioactive constituents as potential functional foods for prevention, treatment and management of cancer.