Anthocyanin Profile and Antioxidant Activity of Edible Leaves of Dissotis brazzae Cogn (Melastomataceae)
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Date
2020
Journal Title
Journal ISSN
Volume Title
Publisher
Journal of Food and Nutrition Sciences
Abstract
Anthocyanins are colored bioactive phytochemicals in the class of flavonoids with high potential as dietary antioxidants. Demand for anthocyanins in functional food and nutraceutical industries has continued to increase over the past decades. However, sources of anthocyanins for commercial exploitation are currently limited. Tropical Africa and Uganda in
particular, harbors many plant species with potential to serve as new sources of anthocyanins. In this study, the anthocyanin
profile and antioxidant activity of edible leaves of Dissotis brazzae, a plant of tropical African origin, were investigated. Two
known anthocyanins, (1) cyanidin 3-O-β-glucopyranoside (1.28±0.44 mg/g fr. wt.) and (2) cyanidin 3-O-α-rhamnopyranoside
(1.89±0.42 mg/g fr. wt.), were isolated from D. brazzae purple leaves by a combination of chromatographic techniques. Their
structures were elucidated mainly by homo- and heteronuclear NMR spectroscopy and online HPLC/UV-Vis spectroscopy. The
isolated anthocyanins showed appreciable level of antioxidant activity against DPPH, with 1 (IC50=9.2±0.2 μg/ml) showing
slightly higher antioxidant potency than 2 (IC50=14.0±0.6 μg/ml). However, quercetin (IC50=4.5±0.4 μg/ml) used as a reference
showed a higher antioxidant activity than 1 and 2. The total anthocyanin content of D. brazzae leaves (317 mg/100g) was within
the range (80 – 680 mg/100g) of anthocyanins content in most dietary sources. This is the first report of fully characterised
anthocyanins from the genus Dissotis, which may be of taxonomic importance. A new dietary source of the rare cyanidin
3-O-α-rhamnopyranoside has been identified.
Description
Keywords
Dissotis brazzae, Anthocyanins, Nutraceutical, Colorant, Dietary Antioxidant, Functional Food
Citation
Adaku, C., Skaar, I., Gumisiriza, H., Byamukama, R., Jordheim, M., & Andersen, O. M. (2020). Anthocyanin Profile and Antioxidant Activity of Edible Leaves of Dissotis brazzae Cogn (Melastomataceae). Journal of Food and Nutrition Sciences, 8(6), 139-145.doi: 10.11648/j.jfns.20200806.11