Phytochemical contents, antioxidant activity and functional properties of Raphanus sativus L, Eruca sativa L. and Hibiscus sabdariffa L. growing in Ethiopia

Ebisa Olika Keyata; Yetenayet B Tola; Geremew Bultosa; Sirawdink Fikreyesus Forsido

doi:10.1016/j.heliyon.2021.e05939

Phytochemical contents, antioxidant activity and functional properties of Raphanus sativus L, Eruca sativa L. and Hibiscus sabdariffa L. growing in Ethiopia

Heliyon. 2021 Jan 13;7(1):e05939. doi: 10.1016/j.heliyon.2021.e05939. eCollection 2021 Jan.

Authors

Ebisa Olika Keyata^{1

2}, Yetenayet B Tola², Geremew Bultosa³, Sirawdink Fikreyesus Forsido²

Affiliations

¹ Department of Food Science and Nutrition, Wollega University, P.O. Box 38, Shambu, Ethiopia.
² Department of Post-Harvest Management, Jimma University College of Agriculture and Veterinary Medicine, P.O. Box: 307, Jimma, Ethiopia.
³ Department of Food Science and Technology, Botswana University of Agriculture and Natural Resources, Private Bag 0027, Gaborone, Botswana.

Abstract

Information on phytochemical contents, antioxidant activity and functional properties of underutilized plants Figl (Raphanus sativus L.), Girgir (Eruca sativa L.) and Karkade (Hibiscus sabdariffa L.) grown in Benishangul Gumuz, Ethiopia are limited. In view of this, leaves and roots of Figl, leaves of Girgir, calyces and seeds of Karkade were evaluated following standard analytical methods. The total flavonoids, total anthocyanins, β-carotene and L-ascorbic acid contents were ranged: 5.28-35.97, 0.01-2.53, 0.15-0.42 and 0.28-1.49 (db mg/g), respectively. The total flavonoids content, total anthocyanins content and antioxidant capacity were high in the brown calyces of Karkade, but are low in the roots of Figl. The antioxidant activity of roots of Figl and seeds of Karkade were low. The effective inhibitory concentration (IC₅₀) toward 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity demanded from brown calyces of Karkade was low and the IC₅₀ was strong negatively correlated with β-carotene and L-ascorbic acid contents (i.e., achieve IC₅₀ with low amounts of these bioactive compounds). The ferric reducing antioxidant power was positively strong correlated with total flavonoids and anthocyanins content. The finding showed that calyces of Karkade can be used as a candidate to substitute synthetic antioxidants and food colorant in food, beverage and pharmaceutical industries because of their high antioxidant capacity, desired color and as a good source of phytochemicals. The study also showed that the leaves of Figl and Girgir were found to exhibit good sources of vitamin C, β-carotene with low bulk density. Because of these properties, they can be regarded as good candidate to supplement micronutrients particularly for vulnerable groups like infants and young children.

Keywords: Antioxidants; Figl; Functional properties; Girgir; Karkade; Phytochemicals.