Effects of condensed tannins prepared from leaves of fodder plants on digestive enzymes in vitro and in the intestine of rats

Abstract

1.Of the nineteen plants screened, six were found to contain large quantities of condensed tannins. Black locust (Robinia pseudo-dcucia), bush clover (Lespedezu bicolor), wistaria (Wistaria floribundu) and Japanese knotgrass (Reynoutria juponicu) were used for the present experiment. Tannins of the investigated plants were fractionated into three or four molecular forms, according to the degree of polymerization, by chromatography on a column of Sephadex LH-20.2. The protein-precipitating capacity of the fractionated tannins increased with the increase in degree of polymerization. The inhibitory effect of tannins on trypsin (EC 3 . 4 . 2 1 .4), a-amylase (EC 3 . 2 . 1 . 1) and lipase (EC 3 . 1 . 1 .3) activities in vitro also increased with the increase in degree of polymerization. The digestion of tannin-bovine serum albumin complex by trypsin was related to the degree of polymerization of tannins complexed.3. Inclusion of black locust tannins in the diet (10 g/kg) depressed the activities of trypsin and a-amylase in the upper, middle and lower parts of the intestine of the rats, but the lipase activity was increased in the middle part and remained unaffected in the upper and lower parts. It is presumed that the tannins have little affinity for lipase. Barry (1985) reported also that the liveweight gain and voluntary intake were low for sheep grazing high-tannin forage. Tannins are classified into hydrolysable and condensed types and the inhibitory effect on trypsin activity is more marked with condensed tannins than with hydrolysable tannins (Tamir & Alumot, 1969). It is also suggested that the principal tannins found in forage leaves are of the proanthocyanidin type formed by the polymerization of flavan-3,4-diols either alone or in combination with other flavonoids such as catechins (McLleod, 1974;Jones et al. 1976). 4.The present work was undertaken to isolate tannins from the leaves of black locust (Robinia pseudo-Acacia), bush clover (Lespedeza bicolor), wistaria ( WistariaJEoribunda) and Japanese knotgrass (Reynoutria juponica) which were found to have proanthocyanidin-type tannins in a survey of tannin-containing plants, and to investigate the effect of isolated tannins on trypsin (EC 3 . 4 . 2 1 .4), a-amylase (EC 3 . 2 . 1 . 1) and lipase (EC 3 . 1 . I .3) in vitro and in the intestine of rats. EXPERIMENTAL Survey of the plants containing condensed tanninsAnthocyanidin-formation and protein-precipitation tests were used for the survey of condensed tannin-containing plants.

Divergence in Structure and Activity of Phenolic Defenses in Young Leaves of Two Co-Occurring Inga Species

“…The BSA precipitation assay showed that there is a strong positive correlation between protein-binding capacity and procyanidin molecular weight, a finding that is in agreement with earlier studies (Kumar and Horigome, 1986;Horigome et al, 1988). Bioassays showed, however, that both the low and high molecular weight fractions were equally inhibitory to H. virescens larvae.…”

Effect of Tannic Acid on Activities of Certain Digestive Enzymes and Alkaline Phosphatase in Intestine and Glucose Absorption in Adult Chickens

“…This deleterious effect is likely due to the reduction in the activities of trypsin and amylase in the digestive tract (Griffiths andMoseley, 1980;Horigome et al , 1988;Longstaff and McNab, 1991b). However, Griffiths and Moseley (1980) and Horigome et al (1988) observed that the activity of lipase increased in the digesta from the rats fed on a diet containing tannin-rich field bean hulls.…”

Changes in the Phytochemical Composition and Profile of Raw, Boiled, and Roasted Peanuts

“…Legumes are inexpensive sources of proteins; however, they contain antinutritional factors such as tannins, phytates, and trypsin inhibitors, which if ingested can reduce the nutritional quality of the food and lead to undesirable physiological effects (14)(15)(16)(17). Therefore, they need to be processed prior to consumption to reduce the levels of these antinutritional factors.…”