Semimicro-estimation of Tannins

Semimicro determination of cellulose in biological materials.

The quantitative determination of cellulose in biological materials presents some difficult problems. The moisture con~ent of cellulose varies with the relative humidity, so that accurate analyses require that moisture determinations be made under carefully standardized conditions. Cellulose ordinarily occurs in association with lignin, polyuronide hemicelluloses, and xylan cellulosans. Matrone...

Tannins of Constant Structure in Medicinal and Food Plants—Hydrolyzable Tannins and Polyphenols Related to Tannins

In addition to the commonly used classification as hydrolyzable tannins and condensed tannins, tannins can also be categorized into two other types: polyphenols of constant chemical structure (Type A) and polyphenols of variable composition (Type B). Both types of tannins and related polyphenols account for a large part of plant polyphenols, but accurate structure-activity correlations on a mol...

A new simple semimicro method for colorimetric determination of urea.

Semimicro method for the determination of salicylate levels in blood.

WIDE VARIETY OF METHODS are available for the determination of salicylate in body fluids and tissues. These range from the spot test type used at the patients’ bedside to the organic solvent partition methods employed in more exact studies. In recent years, the method of Brodie et al. (1) involving extraction with ethylene chloride has gained widespread acceptance. The method commonly employs 1...

Does Propolis Contain Tannins?

Although polyphenols have been reported as common constituents of propolis, tannins have rarely been mentioned as its constituents. Propolis samples from seven localities in Brazil were analyzed for detection of proanthocyanidins (condensed tannins) and determination of the tannin content. Positive reaction for proanthocyanidins was observed for all samples tested. The contents of tannins varie...