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A.W. Frahm

Bio: A.W. Frahm is an academic researcher. The author has contributed to research in topics: Chemical shift & Carbon-13 NMR. The author has an hindex of 1, co-authored 1 publications receiving 71 citations.

Papers
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Journal ArticleDOI
TL;DR: In this paper, the 13 C NMR chemical shifts of eleven hydroxy-, two hydroxymethoxy xanthones, and xanthone- C -glucoside, mangiferin, are presented and analyzed.

73 citations


Cited by
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Journal ArticleDOI
TL;DR: This review, with 350 references, gives information on the chemical study of 234 naturally occurring tetraoxygenated xanthones in 12 families, 53 genus and 182 species of higher plants, and two which are described as fungal and lichen metabolites.

391 citations

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TL;DR: An aqueous decoction of mango stem bark extract is concluded that the product could be useful to prevent the production of reactive oxygen species and oxidative tissue damage in vivo.
Abstract: An aqueous decoction of mango (Mangifera indica L.) stem bark has been developed in Cuba on an industrial scale to be used as a nutritional supplement, cosmetic, and phytomedicine. Previously we reported its antioxidant activity, and we concluded that the product could be useful to prevent the production of reactive oxygen species and oxidative tissue damage in vivo. A phytochemical investigation of mango stem bark extract has led to the isolation of seven phenolic constituents: gallic acid, 3,4-dihydroxy benzoic acid, gallic acid methyl ester, gallic acid propyl ester, mangiferin, (+)-catechin, (-)-epicatechin, and benzoic acid and benzoic acid propyl ester. All structures were elucidated by ES-MS and NMR spectroscopic methods. Quantitative analysis of the compounds has been performed by HPLC, and mangiferin was found to be the predominant component. Total polyphenols were assayed also by the Folin-Ciocalteu method. The free sugars and polyols content was also determined by GC-MS.

287 citations

Journal ArticleDOI
TL;DR: It seems likely that MF exerts its antidiabetic activity by decreasing insulin resistance, and could be useful in treating type-2 diabetes.

207 citations

Journal ArticleDOI
TL;DR: In this article, the 13 C NMR spectra of twenty one iridoid glucosides and fourteen acyl IRD-glucosides of various cyclopentane oxidation states were analyzed and their carbon shifts assigned.

133 citations

Journal ArticleDOI
TL;DR: Four new xanthones have been isolated from the roots of Hypericum roeperanum and exhibited antifungal activity against Candida albicans.

113 citations