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Flavan-3-ols and 2-diglycosyloxybenzoates from the leaves of Averrhoa carambola.
- Source :
-
Fitoterapia [Fitoterapia] 2020 Jan; Vol. 140, pp. 104442. Date of Electronic Publication: 2019 Nov 29. - Publication Year :
- 2020
-
Abstract
- Averrhoa carambola L. (Oxalidaceae) was widely cultivated for fruits (star fruit), whereas the value of leaves remains to be discovered. Our study on the leaves yielded five flavan-3-ols (1-5) and two 2-diglycosyloxybenzoates. Their structures were determined by spectroscopic and chemical methods. Epicatechin-(5,6-bc)-4β-(p-hydroxyphenyl)-dihydro-2(3H)-pyranone (1) and benzyl 2-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyloxybenzoate (6) were new structures. 6-(S <superscript>-2</superscript> -Pyrrolidinone-5-yl)epicatechin (4) and 6-(R-2-pyrrolidinone-5-yl)epicatechin (5) were obtained as monomeric diastereomer for the first time and their absolute configurations were determined by electronic circular dichroism (ECD) computation. Epicatechin-(7,8-bc)-4α-(p-hydroxyphenyl)-dihydro-2(3H)-pyranone (2), epicatechin-(7,8-bc)-4β-(p-hydroxyphenyl)-dihydro-2(3H)-pyranone (3), and methyl 2-β-d-apiofuranosyl-(1 → 6)-β-d-glucopyranosyloxybenzoate (7) were not previously reported from the genus Averrhoa. Compounds 1-5 showed more potent 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical cation and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities and ferric reducing antioxidant power (FRAP) than l-ascorbic acid. Meanwhile 1 and 3 exhibited lipase and α-glucosidase inhibitory activities, respectively. The results clarified the structures of flavan-3-ols and 2-diglycosyloxybenzoates in the leaves and their antioxidant, lipase, and α-glucosidase inhibitory activities.<br /> (Copyright © 2019 Elsevier B.V. All rights reserved.)
- Subjects :
- Antioxidants isolation & purification
Benzoates isolation & purification
China
Flavonoids isolation & purification
Glycoside Hydrolase Inhibitors chemistry
Glycoside Hydrolase Inhibitors isolation & purification
Lipase antagonists & inhibitors
Molecular Structure
Phytochemicals chemistry
Phytochemicals isolation & purification
Antioxidants chemistry
Averrhoa chemistry
Benzoates chemistry
Flavonoids chemistry
Plant Leaves chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 1873-6971
- Volume :
- 140
- Database :
- MEDLINE
- Journal :
- Fitoterapia
- Publication Type :
- Academic Journal
- Accession number :
- 31790769
- Full Text :
- https://doi.org/10.1016/j.fitote.2019.104442