Effects of water stress on antioxidant activity and phenolic contents of African nightshades and their distribution in Kisii and Siaya Counties of Kenya

Abstract

Over the last decade, African nightshades have featured increasingly in both formal and informal markets in different parts of Kenya. African nightshades were to be found only in the backstreets and in a few open-air markets but since then, they have become a common occurrence in most supermarkets, where they are sold in increasing quantities on a daily basis. However, consumption pattern seems to change as more consumers are becoming aware of the importance of health promoting phytochemicals with antioxidants properties present in African nightshades. This observed upward trend in consumption has been attributed partly to the benefits construed to accrue from their consumption. There is scantly scientific report point on the role of the vegetables in alleviation of diseases due to their richness in antioxidants. The study aims to characterize the different African nightshades in different agro-ecologies of Kenya (Kisii, Siaya and Kakamega counties) and assess the effects of water stress on the relative concentration of the antioxidants. The findings will help assign relative significance of the secondary metabolites to abiotic factor (water) and genetic (nightshade accession). The Participatory Rural appraisal will be employed to gather information from farmers on agronomic practices and the various African nightshades being grown. Water stress treatments will be carried out in farmers fields in the selected regions, however a control will be set up in a greenhouse. The treatments will be subjected to randomized complete block design. Different methods will be used in identification and quantification of the main phytochemicals. The researcher proposes to make use of Analysis of variance, data analysis approach to determine the correlations between subjecting the plants of different genotypes to water stress and the accumulation of phytochemicals in different plant