No abstract

Condensed tannins of sorghum seeds could, if also present in vegetative tissue, lower the digestibility of the forage. In order to eliminate interference by pigments such as chlorophyll and anthocyanins in tannin assays of forage, we adsorb tannin and related flavanols on insoluble poly(vinylpyrrolidone) (PVP). After washing out interfering materials we heat the PVP in HC1/butanol to convert the bound tannins to anthocyanidins which are measured spectrophotometrically. By use of this assay, no tannins were found in leaf tissue of the 47 sorghum lines examined. However, leaf tissue from 16 of the lines was found to contain a PVP-binding material with properties corresponding to a monomeric flavan-4-ol (designated a leucoanthocyanidin). The leucoanthocyanidin, which is also present in seed of these varieties, has been tentatively identified as apiforol (4',5,7-trihydroxyflavan-4-ol). This unusual monomeric flavan-4-ol, which has not been previously reported from plants, yields the yellow anthocyanidin, apigeninidin, when heated in aqueous acid and at low temperatures in acid/alcohol mixtures is converted to an unidentified unstable pink anthocyanidin.

No abstract

No abstract

No abstract