Chemical composition of Clinopodium menthifolium aqueous extract and its influence on antioxidant system in black nightshade (Solanum nigrum) and pepper (Capsicum annuum) seedlings and mortality rate of whitefly (Trialeurodes vaporariorum) adults

Abstract

The use of allelochemicals as weed control agents is becoming widely investigated. However, the impact of these bioherbicides on cultivated plants is less known. This study was carried out in order to evaluate the allelopathic effects of the aqueous extract of Clinopodium menthifolium on black nightshade (Solanum nigrum) antioxidant properties to explore the potential of this species in weed control and on pepper (Capsicum annuum) antioxidant properties so as to assess its possible side effects when applied as bioherbicide in organic production. Taking into account that plant extracts should be an alternative source for insect control, additional aim was also to evaluate contact effect of C. menthifolium aqueous extract against the greenhouse whitefly (Trialeurodes vaporariorum). Analysis by HPLC confirmed the presence of gallic acid, caffeic acid and 2-hidroxy-cinnamic acid as major components in the C. menthifolium aqueous extract. Both tested concentrations of C. menthifolium aqueous extract induced lipid peroxidation in black nightshade leaves and roots. It was observed that the aqueous extract with a concentration of 0.1% showed a toxic effect with 50% mortality of greenhouse whitefly adults.

KEY WORDS: Allelochemicals, Antioxidants, Biopesticides, Capsicum annuum, Clinopodium menthifolium, Solanum nigrum, Trialeurodes vaporariorum

Bull. Chem. Soc. Ethiop. 2017, 31(2), 211-222. 

DOI: http://dx.doi.org/10.4314/bcse.v31i2.3