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A 10 weeks study in rats fed a balanced diet containing "hydrosoluble" vitamin A and 3,2 p. 100 by weight of tannic acid resulted in a marked decrease of the hepatic concentration of vitamin A. The same dietary dose of chestnut tree tannins resulted in a much more marked decrease. However, there was no effect of a quebracho extract (condensed tannins) given in the same conditions.
The influences of ultrasonic frequency and ultrasonic time on the extraction rate of Tannin in Elaeagnus angustifolia L. were studied. The optimizing had been got. Results showed that the ultrasonic extraction method of Tannin in Elaeagnus angustifolia L. could save time, improve extraction rates, and need not be hot. Compared with traditional extraction, the ultrasonic extraction method is a good way.
Potassium permanganate titration and complexometry were used to determine the content of tannin in different growth phase of wild and cultivated Cynomorium songaricum Rupr. The result showed that the content appeared regularly changing and the content in coming-up phase was higher than other phases. The quality in this phase would be better if the tannin was regarded as one of the effective components. The result might provide science foundation for the quality control of Herb Cynomorii.
From 42 Rosaceae species, only the Rosoideae species exhibit high tannin content and elastase inhibiting activity such as Filipendula ulmaria, Geum montanum, G. rivale, Alchemilla xanthochlora and Sanguisorba minor. Other studied species from Spiraeoideae, Maloideae and Prunoideae subfamilies are less rich in tannin and also less active.
A 3(2) factor design was carried out in order to investigate the different home-cooking treatments applied in the preparation of pinto beans (Phaseolus vulgaris L.) on the nutritive value of their protein. The factors studied were previous soaking, type of cooking and addition of cooking broth. Biological evaluation of the protein was performed, and the protein efficiency ratio (PER) and apparent digestibility of the protein (DAP) values were obtained. The tannin content was measured in hulls, cotyledons and in the cooking broths of each experimental treatment. The most significant effect of the PER value was the type of cooking (P less than 0.0001), followed by the addition of cooking broth (P less than 0.05) as well as a significant interaction between cooking method and addition of broth (P less than 0.025). Soaking did not have significant effects per se or through its interactions in relation to PER. The highest values for PER and DAP were obtained with the boiling treatment without broth. The detrimental effect of the cooking broth can be explained by its tannin content (108.5-272.25 mg Eq. catechin/100g).
Glycoproteins which contain about 45 mol% proline were dramatically induced in mouse parotid and submandibular glands by isoproterenol treatment, but these unusual proteins were not detected in control animals. These acid-soluble substances were obtained by extracting tissues with 10% trichloroacetic acid, as reported previously for isolating proline-rich proteins from rat submandibular glands (Mehansho, H., and Carlson, D.M. (1983) J. Biol. Chem. 258, 6616-6620). Three major proline-rich glycoproteins were induced in parotid glands with apparent molecular weights of 66,000 (GP-66p), 45,000 (GP-45p), and 27,000 (GP-27p), whereas only one such protein was expressed by the submandibular glands (66,000 (GP-66sm]. Both GP-66p and GP-66sm contained about 19% carbohydrate with the following molar ratios, respectively; GalNAc, 1.0, 1.0; Gal, 1.6, 2.3; GlcNAc, 0.8, 1.1; sialic acid, 0.9, 1.9. The peptide chains of GP-66p and GP-66sm appear to be identical by amino acid compositions, glycopeptide analysis, and preliminary amino acid sequencing data. Northern blot analysis of RNAs from parotid glands of normal and isoproterenol-treated rats, probed with a 32P-labeled proline-rich protein cDNA, confirmed that control animals were devoid of mRNAs encoding these proteins and that isoproterenol treatment dramatically induced expression of these genes. Feeding sorghum high in tannins caused changes in the parotid glands similar to those observed upon isoproterenol treatment, as noted earlier with rats (Mehansho, H., Hagerman, A., Clements, S., Butler, L., Rogler, J., and Carlson, D.M. (1983) Proc. Natl. Acad. Sci. U.S.A. 80, 3948-3952). These glycoproteins have high affinities for tannins as demonstrated by competitive binding curves.
In this work is studied the tannin-iron method specificity when the ferrous chloride is replaced by other iron compounds. Nervous tissue and rat duodenum cuts are used. Cuts were treated with tannic acid and after with FeCl3; FeCl2; FeOHCl2; FeAc2; Fe2O3; FeSO4; NH4Fe(SO4)2 or colloidal iron solution. Dilution effect from every one of aforementioned iron compounds too is studied. The obtained results with those furnished by the OTA method by using the tannic acid in identical conditions are compared. Also several treatments of blockade were carried-out. The obtained results prove that iron ions play a different role in the mucins staining than in other demonstrable substances coloration in the nervous tissue. In the same way evidences that the iron ion that joins the mucins in the tannin-iron method is the FeOH++ ion were obtained.
The effects of dry extract and tannin of Herba Ephedra on adenine-induced chronic renal failure in rats and their mechanisms of action have been studied. Dry extract of Herba Ephedra in dose of 10 mg, 20 mg and 30 mg/d with adenine (for 24 days) were administered to rats. After inducing renal failure (34 days), it reduced toxins in blood significantly. The action of 30 mg-dose was highly significant, BUN decreased by 37%, creatinine (Cr) 35%, methylguanidine (MG) 76%, guanidinosuccinic acid 83%, blood phosphate 39%, while blood calcium raised for 28%. But in 25mg and 45mg-dose, MG in urine decreased by 49%-65%. The mechanisms of action might be including (1) Inhibiting the production of Cr; (2) Inhibiting the production of hydroxyl free radical, blocking the conversion of Cr into creatol, thereby reducing, the production of MG from creatol. In conclusion, dry extract of Herba ephedra could improve renal function in adenine-induced chronic renal failure in rats, correct Ca and P disorder, and especially inhibit the production of MG. Fraction 2 and fraction 3 of Ephedra tannin had no effect on this renal failure model.
Based on cell culture techniques this study has demonstrated that tannin from the pericarp of Punica granatum is an effective component against genital herpes virus (HSV-2). The tannin not only inhibits HSV-2 replication, but also shows stronger effects of killing virus and blocking its absorption to cells.
The presence of antinutritional factors in legume seeds and other vegetables has been considered as an expression of the chemical warfare of plants against their predators. As a consequence, the nutritional utilization of these foods has only been possible through the use of a variety of treatments (cooking, fermentation, germination) which increase nutrient bioavailability. Nonetheless, some factors are not destroyed by effect of seed processing, among which stand a family of polymeric polyphenols called tannins. These pigments have the ability to complex and precipitate proteins and inhibit digestive enzymes. This paper describes what has been accomplished in regards to the selection of an appropriate solvent to extract bean polyphenols, the assessment of the most commonly used assay procedures, the purification of bean tannins and the evaluation of their interaction with proteins and digestive enzymes, responsible for their antinutritional effect.
The effects of A. nilotica (tannin-rich plants) on the digestion coefficient of nutrients and its antibacterial properties were "in-vivo" investigated in this study. Twenty five male baladi goats aged 3-4 years and weighing 19-21 kg were randomly classified into five groups (5 per each). Each animal group was fed on one of the experimental diets containing different levels of A. nilotica leaves (0%, 5%, 10%, 15% & 20%). Chemical analysis of A. nilotica leaves revealed that its content of crude protein, crude fiber, ash were 12.1%, 30.5%, 13.2%, respectively, while the total soluble tannins were 34%. The digestion coefficient of dry matter (DM), crude protein, crude fiber and nitrogen free-extract (NFE) in the control group were better than those of the experimental diets. However, digestion coefficient of most nutrients were significantly decreased (P < 0.01) with increasing levels of A. nilotica in the goat's diets. Absorbed and retained nitrogen (g/day) were decreased with increasing levels of A. nilotica. Concerning nitrogen balance, all animals of the experimental groups showed positive nitrogen balance. Colony forming units (CFU) were drastically reduced in both faecal und ruminal juice samples. This reduction was directly proportional to levels of A. nilotica in the ingested feed. The CFU were reduced in the faecal samples from 5.9 x 10(8)/g (control group) to 2.8 x 10(4) (fifth group) (that received 20% Acacia nilotica). On the other hand, the CFU/ml of ruminal juice samples were reduced from 5.8 x 10(6) (control group) to 1.8 x 10(3) (fifth group). On the other hand, Cl. perfringens count was reduced from 1.0 x 10(4) to 6.3 x 10/g in the faecal samples while their count was reduced from 6.2 x 10(2) to 4.4 x 10/ml in case of ruminal samples. The reduction of total bacterial and Cl. perfringens counts were directly proportional to the levels of A. nilotica in the diets of goats.
Naturally occurring hydrolyzable (HT) and condensed (CT) tannins and their monomeric units were tested for their ability to inhibit the stimulation of DNA synthesis by UVB radiation. Hairless mice were irradiated with either single (200 mJ/cm2) or multiple (150 mJ/cm2) doses of UVB applied at 24 h intervals and epidermal DNA synthesis was measured at different times after the last of these treatments. The peak of DNA synthesis that is observed 48-56 h after a single UVB irradiation shifts to an earlier time of 16-24 h after multiple UVB treatments. Interestingly, the early inhibitory period of DNA synthesis observed 8 h after a single UVB treatment is not detected following multiple UVB treatments. Rather, DNA synthesis is stimulated six-fold 24 h after multiple UVB treatment, a response that is higher than the peak occurring 48-56 h after a single UVB irradiation. The disappearance of the early period of inhibition when the peak of DNA synthesis shifts to an earlier time may be linked to reactive oxygen species brought to the epidermis by infiltrating leukocytes, which, in turn, act as second messengers to stimulate growth signals in cells. Topical applications of HT or CT remarkably inhibit the DNA responses to single and multiple UVB treatments, an effect that is dependent on the dose and time of administration. Indeed, the peak stimulation of DNA synthesis is maximally inhibited when 17 mg of Tarapod tannic acid (TA), an HT, are applied topically 20 min before a single UVB treatment. The polymeric tannins inhibited DNA synthesis to a greater degree than equal doses of their monomeric units, gallic acid and catechin. These results suggest that various oligomeric HT and CT may be useful against tumor-promoting responses associated with the exposure of skin to physical carcinogens.
The role of bioactive tannins in browse in the postpartum performance of goats grazed under natural range conditions was studied using 40 yearling Mubende goats (20+/-0.32 kg). In a completely randomized design, goats of one group (n = 20) received a daily drench of 50 g per goat of polyethylene glycol (PEG) of molecular weight 4000 given as a condensed tannin (CT) deactivator, and goats of the other group (n = 20) acted as the control (no PEG). Mean birth weights, live weight gains, abortion and twinning rates, litter size and tissue energy retention were measured. The PEG drench resulted in lower postpartum weight gains and tissue energy retention (p < 0.05). Postpartum weekly weight loss per doe was 0.65 kg in the PEG group and 0.46 kg in the control group, while tissue energy loss was 17.7 MJ per goat in the PEG group and 10.23 MJ per goat in the control group in the first 8 weeks. Net weight gain was observed in the control group at the 11 th week but was delayed in the PEG group (15th week). The PEG group had lower birth weights and higher kids mortalities (p <0.05). Selective feeding in the Ankole rangeland exposes goats to beneficial concentrations of dietary CT with apparent cumulative effects leading to improved postpartum performance of does and kids.
The photochemistry of several model plant-derived compounds has been studied in aqueous solution. In particular, the reactions of catechin as a model tannin and methoxy-substituted hydroxybenzhydrols as model lignin functionalities were investigated. Tannins and lignins constitute a significant portion of the humic substances in aquatic systems, which are themselves the main component of dissolved organic matter thought to be responsible for the absorption and attenuation of light in these environments. Catechin (1) was found to undergo a reversible photoisomerization reaction to give epicatechin (2). Such a reaction is an explicit example of a photon absorbing process that enables catechin (1) and its derivatives to act as natural sunscreens by attenuating light energy through non-destructive reactions. The methoxy-substituted hydroxybenzhydrols were found to undergo photosolvolysis reactions via efficient generation of quinone methide intermediates. The intermediate quinone methides were observed to be longer lived, and thus more stable, than previously studied hydroxybenzhydrol derivatives. The meta-hydroxybenzhydrol isomer (5) was found to undergo additional chemistry leading to the production of a ring-closed fluorene from the quinone methide intermediate.
A factorial experiment was conducted to study the effects of condensed tannins (CT) from the tropical legumes Desmodium intortum and Calliandra calothyrsus on the digestion and utilization of protein and carbohydrate in sheep and goats. CT-free Centrosema pubescens was also fed for comparison with the CT legumes, and each legume was included (300 g/kg DM) in a basal diet of pangola grass (Digitaria decumbens). Pangola grass alone was used as a control diet. There were no significant (P > 0.05) differences between sheep and goats for the efficiency of digestion of N (0.574, SE 0.013), organic matter (OM; 0.519, SE 0.010), neutral-detergent fibre (NDF; 0.524, SE 0.011) and acid-detergent fibre (ADF; 0.407, SE 0.016). Diets containing desmodium and calliandra were digested less well in the rumen (64 and 62% of total OM digested) when compared with the pangola and centrosema diets (74 and 73% of total OM digested in rumen). There was an apparent net gain of 30% in ADF across the digestive tract of sheep and goats given calliandra, and this gain was ascribed to the formation of 'artifact' fibre as a result of fibre-tannin interaction. Overall, inclusion of legume at 300 g/kg in the diet significantly increased (P < 0.05) the concentration of acetic acid and decreased butyric acid concentration in the rumen fluid of sheep and goats. Significantly higher proportions of dietary N apparently reached the abomasum of animals given the diets containing desmodium (50%) and calliandra (56%) when compared with animals given the centrosema and pangola diets (35%). Sheep and goats given the CT diets also had higher excretions of faecal N. This increment of faecal N (14%) did not affect post-rumen N digestion (P > 0.05) since animals given CT diets absorbed more N (19%) per kg total OM digested than those given the control diets. It was concluded that whilst the low levels of CT provided in desmodium (1.0%) and calliandra (2.3%) diets protected dietary protein from degradation in the rumen, there were no overall beneficial or detrimental effects of CT in these diets for sheep or goats. A method was developed to categorize CT into fractions representative of their forms (free, protein-bound, and fibre-bound) during the digestion process. A quantitative model of CT metabolism during passage through the digestive tract was developed from the measured exchanges of CT between free, protein-bound and fibre-bound pools in the rumen and lower digestive tract. CT interchange mainly occurred in the reticulo-rumen of both animal species. Desmodium and calliandra free CT showed net losses of 68 and 78% in the rumen respectively and 57 and 68% of the fibre-bound CT was lost in the same site for sheep and goats respectively. However, protein-bound CT increased across the rumen by 73 and 56% for both animal species. Post-rumen losses of the total CT abomasal flow were 86 and 83% (free CT) for sheep and goats respectively, 70 and 66% (protein-bound CT), whilst 28% loss of fibre-bound CT occurred in sheep and goats respectively.
We examined the relationship between trunk diameter and diameter relative growth rate (RGR) and fine root condensed tannin concentration in 12 genotypes of eastern cottonwood (Populus deltoides Bartr. ex Marsh.) planted in three locations across the north central United States. Across genotypes, trunk diameter, diameter RGR and root condensed tannin concentration were negatively correlated at one location (Wisconsin), but showed no significant correlation at the other locations (Iowa and Michigan). The factors responsible for this difference among sites remain unidentified, but may be related to soil fertility.
We examined the effects of fertilization and gypsy moth defoliation on condensed tannin concentration (%CT) of hybrid poplar (Populus x canadensis cv 'Eugeneii') fine roots in the summers of 1997 and 1998. This factorial experiment included two defoliation treatments (defoliated and a foliated control) and fertilization treatments (100 kg nitrogen (N) ha(-1) and an unfertilized control). Gypsy moth (Lymantria dispar L.) populations were experimentally increased to obtain defoliation in the summers of 1996, 1997 and 1998; fertilization subplots were supplemented with NH4NO3 (100 kg N ha(-1)) in the spring of each year. Despite the severity of defoliation, the effects were small, and significant on only two sampling dates: in May 1997, when fine root %CT was 23% lower in the defoliated trees, and in November 1997, when trees in the defoliated unfertilized plots had 35% higher root %CT than trees in all other plots. Defoliation effects on root %CT did not follow the same seasonal pattern as defoliation effects on root starch content, N uptake capacity or leaf %CT. Regulation of root condensed tannin concentration appeared to be partially uncoupled from these traits. The small transient effects on root defense reflect the resilience of this early successional tree to severe early season defoliation.
A selective agar plate medium (tannin-treated brain heart infusion agar supplemented with colistin-oxolinic acid) was developed to enumerate tannin-protein complex-degrading Streptococcus bovis in the feces of koalas. This medium was successfully used to enumerate strains from fecal samples but failed to enumerate those from pure cultures.