Free Proanthocyanidins Research Articles

Effect of free and bound proanthocyanidins from Chinese quince on heterocyclic aromatic amine formation and quality in fried chicken.

The abilities of Chinese quince free proanthocyanidins (FP) and bound proanthocyanidins (BP) at different levels (0.1%, 0.15%, and 0.3%) to mitigate heterocyclic aromatic amine (HAA) formation in fried chicken patties were investigated for the first time and compared with vitamin C (Vc). FP and BP reduced HAAs in a dose-dependent manner. Significantly, high concentrations of FP (0.3%) resulted in a reduction of PhIP, harman, and norharman levels by 59.84%, 22.91%, and 38.21%, respectively, in chicken patties. The addition of proanthocyanidins significantly (p<0.05) reduced the weight loss of fried chicken patties. Furthermore, a positive correlation was observed among pH, weight loss, and total HAA formation in all three groups (FP, BP, and Vc). Multivariate analysis showed that FP had a more pronounced effect than BP from the perspective of enhancing the quality of fried chicken patties and reducing the formation of HAAs. These results indicate that proanthocyanidins, both BP and FP, but especially FP, from Chinese quince can inhibit the formation of carcinogenic HAAs when added to protein-rich foods that are subsequently fried.

Fucoidan-proanthocyanidins nanoparticles protect against cisplatin-induced acute kidney injury by activating mitophagy and inhibiting mtDNA-cGAS/STING signaling pathway

Fucoidan (FU) is a natural polymer from marine organisms, which has been widely studied and applied in drug delivery. In this study, FU nanoparticles loaded with proanthocyanidins (PCs) (FU/PCs NPs) were prepared and their effect and mechanism in protecting cisplatin-induced acute kidney injury (AKI) were studied. The in vitro studies confirmed that FU/PCs NPs increased the antioxidant activity of free PCs and protected the death of human kidney proximal tubule (HK-2) cells induced by cisplatin. Further mechanism studies showed that FU/PCs NPs protected the mitochondrial damage induced by cisplatin, activated mitophagy, inhibited the release of mitochondrial DNA (mtDNA), and inhibited the cGAS/STING signal pathway. The in vivo results also indicated that FU/PCs NPs protected cisplatin-induced AKI, including inhibiting the increase of blood urea nitrogen (BUN) and serum creatinine (SCr) levels induced by cisplatin. The mechanism studies confirmed that cisplatin induced an increase in the expression of mitophagy-related protein Pink/Pakrin, mitochondrial mtDNA release and cGAS/STING expression in mice kidney tissues. Pre-administration of FU/PCs NPs further activated mitophagy, as well as inhibiting mtDNA release and cGAS/STING expression. In conclusion, our research proved the role of mitophagy-mtDNA-cGAS/STING signal was involved in cisplatin-induced AKI.

Defense response of pine stem phloem to wounding and treatment with mycelial extracts from Ceratocystis laricicola

Ophiostomatoid fungi colonize the conducting tissues of conifer stems, the phloem and the xylem. These pathogenic fungi penetrate into the stem through injuries made by xylophagous insects vectoring these pathogens. In this study the response of the phloem of Scotch pine (Pinus sylvestris L.) to wounding (treatment 1) was compared with the response to wounding combined with application of high-molecular-weight compounds isolated from the mycelium of the ophiostomatoid fungus Ceratocystis laricicola Redfern & Minter (treatment 2). Both treatments induced the appearance of necrosis in the inner bark, the formation of periderm separating living and dead tissues, and formation of the callus alongside the wound perimeter. In addition, the bark accumulated lignin, bound proanthocyanidins, and resins, with a parallel decrease in the content of free proanthocyanidins, low-molecular-weight carbohydrates, and non-lignin components of the cell wall (P > 0.95). The size of necrotic spots, as well as changes in the content of most substances, were significantly higher in the treatment 2 than in the treatment 1 (P > 0.95). The accumulation of lignin in cell walls of phloem sieve cells was delayed in the treatment 2 as compared with that in the treatment 1. This suggested that the mycelial extract temporarily inhibited lignification at the early stage of the wound response. This disturbance of the cell wall protective transformation led to the hypothesis that the fungal suppressors retard the repair of inner bark injured by insects, thereby favoring the invasion of conifer tissues by ophiostomatoid fungi.

Effect of Pine Callus Elicitation by the Fusarium Strains of Various Pathogenicity on the Content of Phenolic Compounds

Pine (Pinus sylvestris L.) callus culture was treated with the mycelium extracts from six Fusarium strains. Previously, pine seedlings were infected with a spore suspension in order to test the pathogenicity of the used strains. Callus culture infection resulted in a decrease in the free proanthocyanidin (PA) and an increase in bound PA content. After treating the calli with all strains except F. oxysporum var. orthoceras, the lignin content became lower than the control one. The most considerable changes involved the p-hydroxybenzoic acid (HBA) content, and its greatest change was observed after treating the calli with F. nivale, when the HBA concentration (1229 μg/g dry wt) exceeded fourfold the control one. There was a positive correlation (R = 0.81) between the HBA content in the callus culture cells treated with a fungal extract and the virulence of Fusarium strains. At the same time, there was an inverse correlation (R = –0.80) between the lignin content in a callus culture and the fungal virulence; the latter did not affect the contents of both free and bound PA.

Effects of feeding quebracho tannin diets, with or without a dietary modifier, on rumen function in sheep

AbstractThe effect of quebracho tannin (QT) on the activities of rumen microbes was studied both in vivo and in vitro. The in vivo study was carried out in four rumen environments created by feeding four fistulated sheep a basal diet of chopped grass hay, grass cubes and whole barley (control) with or without the addition of QT and the dietary modifier Browse Plus (BP). The active ingredients in BP are polyethylene glycol (PEG, more than 0·95 of the dry material), polyvinyI pyrrolidone (PVP) and calcium hydroxide. The diets offered were control, control plus 50 g QT per kg diet (CQT), control plus 50 g QT per kg and 0·1 (CQT+ 0·1) or 1.0 g BP per kg (CQT + 1·0). The experiment was a 4 X 4 Latin-square design with periods of 4 weeks. Rumen liquor samples were collected at 0, 2, and 8 h after feeding, 18 and 25 days after commencement of each period. Changes in free and bound proanthocyanidin (PA) concentrations, rumen pH, ammonia, volatile fatty acids (VFA), soluble protein concentrations, particle-bound cellulase and xylanase activities and rumen protozoal counts were used as indices of microbial activities. The same diets were incubated with rumen contents in vitro, except that the 0.1 g/kg level of BP was replaced by a fourth treatment made up of control plus 1·0 g BP per kg DM of hay (CBP). In vivo, bound PA concentrations in the rumen liquor of all the sheep given QT-containing diets were higher than those of the free PAs. The bound PA was higher (V &lt; 0·05) in the rumen liquor of sheep given CQT in comparison with those containing BP. There were reductions in ammonia (P &gt; 0·05), soluble protein (P &lt; 0·05) and total VFA (P &gt; 0·05) concentrations in the rumen liquor of sheep given CQT in comparison with those given the control and BP-containing diets. Reductions (P &gt; 0·05) were also observed in the cellulase and xylanase activities of the rumen microbes and in protozoal counts (P &lt; 0·05) in the presence of QT in the diet. In vitro, QT reduced (P &gt; 0·05) the viable bacterial counts, gas production and the total VFA concentrations after incubation. In both the in vivo and in vitro experiments, BP was able to alleviate some but not all of the depression in microbial activities. The main constituent (PEG) in BP binds to some of the tannins in solution and may displace tannins from tannin-protein complexes.