Plant secondary metabolites are the compounds produced by plants that are not directly involved in their growth and development but play vital roles in their survival helping them in their defence against diverse biotic and abiotic stress factors. These phytochemicals are also involved in attracting and stimulating activities exhibited by the plants during pollination, seed dispersal, plant-microbe interaction, allelopathy and many others. These natural compounds contribute to colour, flavour, and disease resistance in plants. These bio-active metabolites are recognised for their health-promoting, disease-prevention and therapeutic roles in humans. They are referred to as phytonutrients because when consumed by humans provide numerous health benefits and are considered crucial components of functional foods. They exhibit various biological activities such as antioxidant, anti-inflammatory, antimicrobial, and anticancer effects. The phytonutrients are recognised as the functional food responsible for promoting health and are often recommended as part of a balanced diet.