Inhibition of digestive enzymes by condensed tannins from green and ripe carobs

Tamir, Musha; Alumot, Eugenia

doi:10.1002/jsfa.2740200402

Cited by 121 publications

(32 citation statements)

References 20 publications

(2 reference statements)

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“…Other similarities between the effects of carob extract and tannins on seedling growth have already been discussed (10). Tannins are well known to be general protein denaturants in the tanning of animal hides, and their effect on specific enzymes has been well documented (2,4,12,15,24). In the present study, the activity of preformed enzymes was not reduced by the addition of tannins, and this may reflect selective activity on the part of the tannins.…”

Section: Discussionsupporting

confidence: 55%

Tannins as Gibberellin Antagonists in the Synthesis of α-Amylase and Acid Phosphatase by Barley Seeds

Jacobson

Corcoran²

1977

Plant Physiol.

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The tannins chebulinic acid or tarn tannin were added to an incubation system in which GA3 induces enzyme synthesis in endosperm half seeds of barley (Hordeum vulgare L.). The activity of amyase and acid phosphatase in the incubation medium was reduced compared to the activity in the medium after incubation with GA3 alone. When embryo half seeds of barley were incubated with chebulinic acid or tan tannin in the absence of added GA3, the enzyme activity of the incubation medium was also reduced. The activity of preformed enzymes obtained from endosperm half seeds previously induced with GA3 was not reduced by the addition of tannin. Comparisons were made of the amount of enzyme activity from breis of aleurone layers incubated with GA3 in the presence and absence of tannins. The amounts of activity were relatively small and approximately equal in both cases, indicating that secretion from the aleurone was not blocked by the tannins. The reduction of enzyme activity caused by tannins in both endosperm and embryo half seeds could be completely reversed by the addition of GA3.Although the chemistry of tannins has been studied for over a century and their existence has been known for thousands of years, their function in the plant has received little attention, and remains essentially unknown. Recently, several tannins have been shown to reduce the GA-induced growth of seedlings (11,13,14). The effect is general to both condensed and hydrolyzable tannins. Seedlings of cucumber, pea, and rice have all been used as test plants, and growth induced by any of seven different GAs can be inhibited. The endogenous growth of the plants is not affected and the inhibition is completely reversed by additional GA.The widespread occurrence of compounds antagonistic to such important plant hormones as GAs suggests that tannins may have a role in the normal regulation of GA-induced processes. If tannins are involved in this way, then other GA effects besides shoot growth would be expected to be inhibited. Also, it would be expected that tannins could affect endogenous development normally regulated by GA. The present study concerns the effects of tannins on induction of the hydrolytic enzymes amylase and acid phosphatase in barley seeds. This paper reports that chebulinic acid and tara tannins inhibit enzyme synthesis whether the seeds are induced by exogenous or endogenous GA. Additional GA will completely reverse the inhibition in all cases tested. Schaller, University of Calif., Davis) were prepared and treated as described by Vamer and Chandra (26). Seeds were cut in half transversely to give either a 3-mm endosperm half and an embryo half which was discarded, or to give a 3-mm embryo half and an endosperm half which was discarded. The seed halves were sterilized in 1% sodium hypochlorite (commercial bleach) for 20 min and rinsed five times with sterile distilled H20. Sterilized endosperm halves were then preincubated on sterile moist sand in Petri dishes for 3 days. Sterilized embryo halves were similarly preincubated f...

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Section: Discussionsupporting

confidence: 55%

Tannins as Gibberellin Antagonists in the Synthesis of α-Amylase and Acid Phosphatase by Barley Seeds

Jacobson

Corcoran²

1977

Plant Physiol.

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“…Considering tannin level given for coffee pulp, amount of coffee pulp used in our experiment could be sufficient to induce such inhibition. Moreover, inhibition of amylase and lipase by tannin were also described (Longstaff and Mc Nab, 1991;Quesada et al, 1996;Tamir and Alumot, 1969). This could also explain the observed poor utilisation of feed as a whole.…”

Section: Discussionmentioning

confidence: 83%

Dietary utilisation of protein and energy from fresh and ensiled coffee pulp by the Nile tilapia, Oreochromis niloticus

Moreau

Arredondo

Perraud-Gaime³

et al. 2003

Braz. arch. biol. technol.

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“…Those compounds are responsible for the presence of sediment and haze in juice [45]. An excessive content of polyphenols, in particular tannins, may have adverse consequences because it inhibits the bioavailability of iron [46,47] and thiamine [48] and blocks digestive enzymes in the gastrointestinal tract [33,49]. Phenolic compounds can also limit the bioavailability of proteins with which they form insoluble complexes in the gastrointestinal tract [33,50].…”

Section: Phenolic Compoundsmentioning

confidence: 99%

“…The tart taste results from the interactions between tannins and the proteins of mucous membranes and gustatory receptors. As enzyme inhibitors, tannins decrease the nutritive value of some plant products [33,49,51]. In fruit rich in anthocyanins, tannins stabilize anthocyanins by binding to them to form copolymers [33,81].…”

Section: Tanninsmentioning

confidence: 99%