Prosopis cineraria leaf tannins: their inhibitory effect upon ruminal cellulase and the recovery of inhibition by polyethylene glycol-4000.

The condensed tannins from the Prosopis cineraria leaves were purified and fractionated in two groups (Kav 0.018 and 0.74) on a column of Sephadex LH-20 (2.5 x 27 cm) using 70 percent aqueous acetone as the eluent. The Kav for catechin was 0.946. Upon acid hydrolysis, both the condensed tannin fractions yielded three pigments including cyanidin-chloride, which was separated by column chromatography using polyvinylpyrrolidone absorbent and was identified by paper chromatography (Rf Forestal 0.476) and absorption maxima (lambda max 535 nm) in 1 percent HCl in methanol. The condensed tannin fraction Kav 0.74 at 0.01 percent and 0.02 percent in incubations with butanol-acetone powder of rumen liquor, inhibited cellulase activity by 65.9 +/- 2.1 and 78.99 +/- 4.5 percent, respectively. Inclusion of 0.5 percent of polyethylene glycol -4000 in the incubation mixture, reduced the inhibition to 41 and 46 percent, respectively.