Carotenoids, pigments, phenolic composition and antioxidant activity of Oxalis corniculata leaves

Abstract

Carotenoids, pigments, phenolic composition and antioxidant activity of Oxalis corniculata leaves grown in dry, marshy and moist areas were evaluated. High-performance liquid chromatography analyses showed 13 phenolic compounds, which were higher in samples from dry areas, followed by those from marshy and moist areas. Kaempferol-3-sophorotrioside, quercetin-3-(caffeoyldiglucoside)-7-glucoside, isorhamnetin-3-caffeoyl-7-glucoside, and p-coumaric acid were the major compounds. High levels of all-E-violaxanthin, all-E-neoxanthin, all-E-lutein, and 9-Z-lutein were present in samples from marshy and moist areas. Phytofluene, hydroxy-pheophytin a, and chlorophyll b were major pigments. Pigments were higher in samples from marshy areas, followed by moist and lowest in dry area samples. Total phenolic and flavonoids contents varied among the samples. Oxalis corniculata leaves showed high radical scavenging activity attributed to the high levels of carotenoids and phenolic compounds. Results showed that Oxalis corniculata leaves are a good source of bioactive substances such as carotenoids and phenolics for the uses in food fortification and as ingredients.