Characterization of Flavonoids from Candidate Striga Weed Controlling Food Legumes; Cicer arietinum L. and Vigna radiata L.

In Africa, intercropping of some legumes with cereal crops has been found to cause remarkable reduction of Striga infestation and improved production of cereal crop. Desmodium uncinatum controls Striga infestation in intercrop with cereals through an allelopathic mechanism, which involves post-germination growth inhibitors exuded from the roots. Allelopathy is a natural and environmentally friendly technique, which has a potential to be a new approach for weed control. A standardized profiling method based on Reverse Phase-High Performance Liquid Chromatography (RP-HPLC) and Liquid Chromatography coupled with Mass Spectrometry (LC/MS) was used to identify flavonoids in extracts of chickpea (Cicer arietinum) and mung bean (Vigna radiata), potential trap crops for Striga weed. Nine flavonoids including mono- and diglycosyl derivatives of fisetin, baicalein, rahamnetin, isorhamnetin, formonometin, quercetin, isosakuranetin, and sakuranetin were tentatively identified. The detected phenolics were present at concentrations greater than 0.001% of the dry materials. Many of these phenolic compounds have been reported to have human health benefits. These glycosylated flavones are reported for the first time in these two species. The comprehensive analysis of the polar secondary metabolites in these leguminous plants was helpful for understanding their inhibitory chemistry and proposed biosynthesis by C-glucoside traits. All the isolated and characterized compounds in the food legume C. arietinum were O-glucosylated. While, Food legume V. radiata should be examined further to see if it can attain Desmodium’s allelopathic ability since it possess inhibitory chemistry and proposed biosynthesis by C-glucosylation.