Geeta Mahto* & Jyoti Kumar
University Department of Botany, Ranchi University, Ranchi, Jharkhand, India
Received : 15th December, 2017 ; Revised : 11th February, 2018
Abstract : Nitrite (NO2) and nitrate (NO3) are as a part of nitrogen natural cycle and essential nutrients for plant protein synthesis. Plants take nitrogen in ionic form from soil. Nitrate is a naturally occurring form of nitrogen formed from fertilizers, decaying plants, manure and other organic residues. Due to increased use of synthetic nitrogen fertilizers and livestock manure in agriculture, vegetables and drinking water may contain higher concentrations of nitrate now than in past. Nitrate is also used as a food additive, mainly as preservative and antimicrobial agent. Its level commonly present in food is not toxic to humans but they act as the reservoir for conversion to nitrite by intestinal flora. A high nitrate accumulation in plants results in nitrite production, which then converted into nitric oxide (NO) which, together with O2, could be rapidly catalyzed by nitrate reductase into peroxynitrite (ONOO-). The presence of nitrite and nitrate in food chains is associated with numerous health problems including stomach, gullet and gallbladder cancer and methaemoglobinaemia. This review focuses on the factors for accumulation of nitrate and nitrite in some plants and its potential risks on human health.