Variation in antioxidant capacity of quinoa (Chenopodium quinoa Will) subjected to drought stress

► Results of this research indicated that antioxidant activity in quinoa seed increased when water supplementation was restricted. ► Water restriction did not affect vitamin E content of quinoa under controlled water stress. ► Seed yield of quinoa genotypes was affected in different magnitude when plants were subjected to drought stress. ► Quinoa seeds had high level of total phenolic compound with a weak correlation between DPPH and CUPRAC assays. ► It is possible to increase phytochemical compounds to improve functional quality of quinoa by selecting genotype with phenotypic elasticity, under water stress conditions.