**Abstract**

The traditional and herbal medicines play significant role in the treatment of several diseases. These medicines are the outcome of extensive research on therapeutic and preventive activity of various plant species and their specific parts. Administration of various plant parts, vegetables, fruits and other herbal constituents have significant impact on reduction of clinical, carcinogenic and genotoxic effects of various environmental toxicants. Various parts of plant such as wood, bark, stem, leaf and pod are rich in antioxidants which are known for their free radical scavenging activity. Currently, the treatment options rely significantly using natural anti-oxidants which are extracted from plant products because these are largely available, cost effective and non-toxic as compared to the synthetic drugs. Some potent natural anti-oxidants include tocopherol, ascorbic acid, flavonoids, quercetin, carotene, cinnamic acid, peptides and phenolic compounds which are extensively available in various herbal extracts. The present chapter will focus upon availability of various antioxidants in vegetables and other medicinal plants and their potential activities against xenobiotics.

**Keywords:** vegetables, flavonoids, antioxidants, medicinal plants, therapeutic

## **1. Introduction**

The traditional health care system of India known as Ayurveda, is considered as the oldest medical system. Throughout history, plants (vegetables and fruits) have been used as a medicine to treat and prevent diseases on both a traditional and popular level. In India, Ayurveda has been practiced for decades as a natural method of preventing and curing diseases, and plants have a significant role to play in this process [1]. Ayurveda, the science of longevity is a collection of multiple therapeutic measures and defines various conditions of illness and measures to combat them with natural practices. It is estimated that traditional herbal medicines have existed for at least 3000 years. The medicines or extracts prepared using whole plant or some specific parts of the plant are usually termed as phytomedicines or phytoextracts.

These compounds possess potent antioxidant properties. Antioxidants are the molecules or compounds that delay the process of oxidation. The important constituents present in plant products are flavonoids, alkaloids, terpenes, bisbenzyls and coumarins that have potential medicinal value [2]. Nowadays a great attention has been focused on natural anti-oxidants containing plant products due to their easy availability, cost effective and non-toxic nature as compared to the synthetic drugs [3]. Various plants

products are recommended for their antioxidative, anticarcinogenic, anti-tumorigenic, healing and chelating property [4]. It has been shown that populations consume food rich in natural antioxidants have a lower incidence of diseases related to oxidative damage and cancer [5].

Various plant species have been studied with promising results. Many vitamins and minerals are found in plant products. They are also naturally rich in antioxidants, which protect the body against aging and illnesses such as cancer and heart disease. Alkaloids, flavonoids, glycosides, lactones, resins, sterols, and sterol derivatives are among the secondary metabolites that medicinal plants synthesize naturally. A wide range of bioactive compounds have been identified in modern science, allowing the development of new drugs from plants. Numerous plant compounds have shown potential efficacy against life threatening diseases which further requires study of mechanisms of action, pre-clinical research and clinical trials. Around 80% of Africa's population is dependent on these traditional medicines for their health care. Research has shown utilization of medicinal plants in the treatment and prevention of chronic diseases [6].

In this chapter, we have discussed the beneficial aspects of few medicinal plants and their special parts. Medicinal plants and Ayurvedic medicines are becoming increasingly popular due to the skyrocketing price of allopathic drugs [7]. The most valuable part of aloe vera is its gel and latex of its leaves, whereas, in turmeric, the rhizome shows most of the medicinal properties [8, 9]. The leaves of tea tree are used, while the leaves, flowers and seeds of Ashwagandha plant are useful for medicinal purposes whereas the whole plant of *Centella asiatica* is useful and from Holy Basil the leaves are found to be beneficial for treatment of many diseases [10–13]. In Moringa oleifera, many phytoconstituents are found in its leaves, flower, seeds, roots and stem bark [14]. The berries and seeds of Sea Buckthorn are very useful however, in Amla, the fruit is most useful [15, 16]. Garlic is a bulbous plant whose bulb is very useful. These plant parts can either directly be used as medicines or for the synthesis of therapeutic compounds. Thus, present chapter focus on the use of herbal products against adverse effects of various xenobiotics. It is essential to explore and identify the importance of natural system of medicines and modify it as per the current need.
