Volume 100, September 2015, Pages 75–79
Highlights
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- Roots of Rafnia amplexicaulis and R. acuminata are early Cape substitutes for liquorice root.
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- Rafnia leaves and roots are used as traditional medicine and as herbal teas.
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- Genistein 8-C-β-d-glucoside is identified as the main compound (NMR, MS, crystal structure).
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- This isoflavone C-glycoside is responsible for the intense bittersweet taste.
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- Rafnia species may have potential as new ingredients of herbal teas and functional foods.
Abstract
The roots of Rafnia amplexicaulis
have been used as a substitute for liquorice root and the leaves as a
traditional medicinal tea in Cape (Khoi-San and Cape Dutch) Herbal
Medicine. All published ethnobotanical data are presented, showing that
two other species, Rafnia acuminata and Rafnia angustifolia, have also been used as a source of tea. The major compound of the roots and leaves of Rafnia amplexicaulis,
responsible for the intense bittersweet taste, was isolated and
identified as 8-glucopyranosyl-4,5,7-trihydroxyisoflavone (genistein 8-C-β-d-glucoside). The structure was determined on the basis of NMR and MS data, as well as X-ray crystallographic analysis. R. amplexicaulis
and related species are a newly discovered source of this isoflavone (a
compound with demonstrated antioxidant and radioprotective effects)
that may be at least partly responsible for the traditional uses in
treating asthma, influenza, back problems, infertility, catarrh and
wasting. Rafnia species may therefore have potential value as new ingredients of herbal teas and functional foods.
Keywords
- Cape herbal tea;
- Crystal structure;
- Genistein-8-C-glucoside;
- Isoflavone C-glycoside;
- Liquorice (licorice) substitute
Copyright © 2015 South African Association of Botanists. Published by Elsevier B.V. All rights reserved.
