Condensed tannins. 3. Isolation and estimation of (−)-7:3′:4′:5′-tetrahydroxyflavan-3-ol, (+)-catechin and (+)-gallocatechin from black-wattle-bark extract
Year: 1960
Type: article
Abstract: The bark and heartwood extractives of the blackwattle tree (Acacia Moll88ima) both contain mix- tures of complex polyphenolic compounds con- sisting of a molecular-weight gradation within the range 300-3000 (Roux & Evelyn, 1958a, c).Keppler (1957) showed that wattle-heartwood ex- tractives contain a (+ )-7:3':4'-trihydroxyflavan-3:4-diol, which appears to be the prototype and possible precursor of some of the condensed tannins of the wood (Roux, 1958 b), and which was found to be enantiomorphous (Clark-Lewis & Roux, 1958, 1959) with a similar monomeric (-)-leuco-fisetinidin prototype of quebracho (Schinop8i8 balan8ae and S. quebracho-colorado) heartwood tnins (Roux, 1958a; Freudenberg & Weinges, 1958; Roux & Evelyn, 1958b).Roux & Maihs (1958) have briefly reported the isolation from the fresh bark extract of (-)-7:3':4':5'-tetrahydroxyflavan-3-ol, in addition to (+ )-catechin and (+ )-gallocatechin.The present study provides details of the isolation, characterization and estimation of these catechins. EXPERIMENTAL AND RESULTSAll melting points are uncorrected.Mixed melting points were made on the crystalline residue remaining after dis- solving equal weights of both compounds in methanol and removing the methanol under vacuum.Analyses of C, H, methoxyl and acetyl are by Weiler and Strauss, Oxford.Infrared comparisons were made by Dr J. R. Nunn, National Chemical Research Laboratory, C.S.I.R., Pretoria.Tannin analyses are by the ultraviolet photometric method for black-wattle tannins (Roux, 1951, 1957a, b), standard- ized against the hide-powder (shake) method.
Source: Biochemical Journal
DOI: 10.1042/bj0740044
Authors: D. G. Roux, E. A. Maihs
Institution: Rhodes University
Language: English
Subfield: Applied Microbiology and Biotechnology
Field: Immunology and Microbiology
Domain: Life Sciences
Open Access status: bronze
OpenAlex ID: W1785648421