Proanthocyanidin-rich Extracts Research Articles

Characterization and Anti-Ultraviolet Radiation Activity of Proanthocyanidin-Rich Extracts from Cinnamomum camphora by Ultrasonic-Assisted Method.

The ultrasonic-assisted extraction (UAE) method was employed to separate Cinnamomum camphora proanthocyanidin-rich extracts (PCEs). This extraction process was optimized by the Box-Behnken design, and the optimal conditions, on a laboratory scale, were as follows: an ethanol concentration of 75%, a liquid-to-solid ratio of 24 mL/g, an ultrasonic time of 39 min, and an ultrasonic power of 540 W. Under the obtained conditions, the PCE yield extracted by UAE was higher than that from heat reflux extraction and soaking extraction. An ultra-performance liquid chromatography-tandem mass spectrometry analysis was employed to characterize the phloroglucinolysis products of the C. camphora PCEs, by which epigallocatechin, catechin, epicatechin, and (-)-epigallocatechin-3-O-gallate were identified as the terminal units; epigallocatechin, epicatechin, and (-)-epigallocatechin-3-O-gallate were recognized as extension units. The C. camphora PCEs possessed higher anti-ultraviolet activity in vitro compared with the commercially available sunscreen additive of benzophenone with respect to their ethanol solutions (sun protection factor of 27.01 ± 0.68 versus 1.96 ± 0.07 at a concentration of 0.09 mg/mL) and sunscreens (sun protection factor of 17.36 ± 0.62 versus 14.55 ± 0.47 at a concentration of 20%). These results demonstrate that C. camphora PCEs possess an excellent ultraviolet-protection ability and are promising green sunscreen additives that can replace commercial additives.

Alkaline oxidization can increase the in vitro antiparasitic activity of proanthocyanidin-rich plant extracts against Ascarissuum

Proanthocyanidins (PAs) are a class of plant specialized metabolites with well-documented bioactivities such as antiparasitic effects. However, little is known about how the modification of PAs influences their bioactivity. The objective of this study was to investigate a wide range of PA-containing plant samples to determine if extracts containing PAs modified by oxidation had altered antiparasitic activities, compared to the original extracts that had not been modified in alkaline conditions. We extracted and analyzed samples from 61 proanthocyanidin-rich plants. The extracts were then oxidized under alkaline conditions. We used these non-oxidized and oxidized proanthocyanidin-rich extracts to conduct a detailed analysis of direct antiparasitic effects against the intestinal parasite Ascaris suum in vitro. These tests showed that the proanthocyanidin-rich extracts had antiparasitic activity. Modification of these extracts significantly increased the antiparasitic activity for the majority the extracts, suggesting that the oxidation procedure enhanced the bioactivity of the samples. Some samples that showed no antiparasitic activity before oxidation showed very high activity after the oxidation. High levels of other polyphenols in the extracts, such as flavonoids, was found to be associated with increased antiparasitic activity following oxidation. Thus, our in vitro screening opens up the opportunity for future research to better understand the mechanism of action how alkaline treatment of PA-rich plant extracts increases their biological activity and potential as novel anthelmintics.

Anti-degranulation and bile acid-binding activity of extracts from fruits and agro-industrial by-products

To evaluate the utility of fruits and by-products/wastes as bioactive materials, we investigated the anti-allergic effects of hot-water and ethanol extracts from various fruit by-products and medicinal fruits using a β-hexosaminidase release assay. Bile acid-binding ability, which is related to the acceleration of bile acid excretion, was also determined for hot-water extracts. Among the extracts, the ethanol extract of grape bunch stem showed the highest (63.6%) inhibition of degranulation, as assessed by β-hexosaminidase release from rat basophilic leukemia cells (RBL-2H3) at a dose of 100 μg/mL. The hot-water extract from grape seed contained the highest total polyphenol content (353 mg gallic acid equivalent/g dry extract), but the total polyphenol content did not show a high correlation with the anti-degranulation effect. A positive relationship between the inhibitory effect of degranulation and proanthocyanidin content (0.1–0.3 in A550) was observed, but higher concentrations of proanthocyanidins in the system showed adverse effects. Proanthocyanidin content was also related to the bile acid-binding ability of the hot-water extracts with the highest value from Chinese quince hot-water extract (95%, 47.7 mg/g dry extract). These results suggest that proanthocyanidin-rich extracts from fruits and agro-industrial by-products have bioactive potential and can be exploited as anti-degranulation and bile acid-eliminating materials.

Bioavailability of red wine and grape seed proanthocyanidins in rats.

This study explored plasma levels and urinary and fecal excretion of metabolites and microbial-derived catabolites over a 24 h period following the ingestion of red wine (RWP) or grape seed (GSP) proanthocyanidin-rich extracts by rats. In total, 35 structurally-related (epi)catechin metabolites (SREMs) and 5-carbon side chain ring fission metabolites (5C-RFMs) (phenyl-γ-valerolactones and phenylvaleric acids), and 50 phenolic acid and aromatic catabolites were detected after intakes of both extracts. The consumption of the RWP extract, but not the GSP extract, led to the appearance of a ∼200 nmol L-1 peak plasma concentration of SREMs formed from flavan-3-ol monomers. In contrast, ingestion of the GSPs, but not the RWPs, resulted in a substantial increase in microbiota-derived 5-carbon side chain ring fission metabolites (5C-RFMs) in plasma. 5C-RFMs, along with low molecular weight phenolic catabolites were detected in urine after ingestion of both extracts. The GSP and RWP extracts had respective mean degrees of polymerisation 5.9 and 6.5 subunits, and the RWP extract had an upper polymer size of 21 subunits compared to 44 subunits for the GSP extract. The differences in plasma metabolite profiles might, therefore, be a consequence of this polydispersity impacting on the microbiota-mediated rates of cleavage of the proanthocyanidin subunits and their subsequent metabolism and absorption. Urinary excretion of phenolic catabolites indicated that 11% of RWPs and 7% for GSPs were subjected to microbial degradation. In all probability these figures, rather than representing the percentage of proanthocyanidins that are completely degraded, indicate partial cleavage of monomer subunits producing a much higher percentage of shortened proanthocyanidin chains. Obtaining more detailed information on the in vivo fate of proanthocyanidins is challenging because of the difficulties in analysing unabsorbed parent proanthocyanidins and their partially degraded flavan-3-ol subunit chains in feces. Further progress awaits the development of improved purification and analytical techniques for proanthocyanidins and their use in feeding studies, and in vitro fecal and bacterial incubations, with radio and/or stable isotope-labelled substrates.

Roles of proanthocyanidin rich extracts in obesity.

Obesity is a multifactorial disorder involving an abnormal or excessive amount of body fat. Obese people have a very high probability of developing metabolic syndrome, a condition in which cholesterol, lipid, and glucose levels rise, causing diabetes and heart disease. From the point of view of energy balance, the main contributors to obesity are excessive energy intake, inadequate energy expenditure and metabolic malfunctions. For this reason, health organisations are working to implement policies and plans to promote healthy eating and active living. However, these measures have not yet proven sufficient to combat this worldwide epidemic; therefore, drugs and bioactive compounds are being investigated to complement the existing strategies. In the present review, we discuss the available data regarding the modulation of obesity by proanthocyanidin rich extracts. Because studies with human subjects are very scarce, we focus on studies using laboratory animals. The results of in vitro studies are included because, although they cannot be directly extrapolated to the biological effects of proanthocyanidin, they can reveal some mechanisms of action.

Neuroprotective effects of anthocyanin- and proanthocyanidin-rich extracts in cellular models of Parkinson׳s disease

Neuropathological evidence indicates that dopaminergic cell death in Parkinson׳s disease (PD) involves impairment of mitochondrial complex I, oxidative stress, microglial activation, and the formation of Lewy bodies. Epidemiological findings suggest that the consumption of berries rich in anthocyanins and proanthocyanidins may reduce PD risk. In this study, we investigated whether extracts rich in anthocyanins, proanthocyanidins, or other polyphenols suppress the neurotoxic effects of rotenone in a primary cell culture model of PD. Dopaminergic cell death elicited by rotenone was suppressed by extracts prepared from blueberries, grape seed, hibiscus, blackcurrant, and Chinese mulberry. Extracts rich in anthocyanins and proanthocyanidins exhibited greater neuroprotective activity than extracts rich in other polyphenols, and a number of individual anthocyanins interfered with rotenone neurotoxicity. The blueberry and grape seed extracts rescued rotenone-induced defects in mitochondrial respiration in a dopaminergic cell line, and a purple basal extract attenuated nitrite release from microglial cells stimulated by lipopolysaccharide. These findings suggest that anthocyanin- and proanthocyanidin-rich botanical extracts may alleviate neurodegeneration in PD via enhancement of mitochondrial function.

Serum metabolites of proanthocyanidin-administered rats decrease lipid synthesis in HepG2 cells

The regular consumption of flavonoids has been associated with reduced mortality and a decreased risk of cardiovascular diseases. The proanthocyanidins found in plasma are very different from the original flavonoids in food sources. The use of physiologically appropriate conjugates of proanthocyanidins is essential for the in vitro analysis of flavonoid bioactivity.In this study, the effect of different proanthocyanidin-rich extracts, which were obtained from cocoa (CCX), French maritime pine bark (Pycnogenol extract, PYC) and grape seed (GSPE), on lipid homeostasis was evaluated. Hepatic human cells (HepG2 cells) were treated with 25 mg/L of CCX, PYC or GSPE. We also performed in vitro experiments to assess the effect on lipid synthesis that is induced by the bioactive GSPE proanthocyanidins using the physiological metabolites that are present in the serum of GSPE-administered rats. For this, Wistar rats were administered 1 g/kg of GSPE, and serum was collected after 2 h. The semipurified serum of GSPE-administered rats was fully characterized by liquid chromatography tandem triple quadrupole mass spectrometry (LC–QqQ/MS2). The lipids studied in the analyses were free cholesterol (FC), cholesterol ester (CE) and triglycerides (TG).All three proanthocyanidin-rich extracts induced a remarkable decrease in the de novo lipid synthesis in HepG2 cells. Moreover, GSPE rat serum metabolites reduced the total percentage of CE, FC and particularly TG; this reduction was significantly higher than that observed in the cells directly treated with GSPE. In conclusion, the bioactivity of the physiological metabolites that are present in the serum of rats after their ingestion of a proanthocyanidin-rich extract was demonstrated in Hep G2 cells.

Protective effect of grape seed extract against ischaemia/reperfusion injury in a rat epigastricflap model

Proanthocyanidins are potent natural antioxidants which belong to a class of polyphenols. Proanthocyanidin-rich extracts are prepared from grape seeds. The effect of grape seed proanthocyanidin extract (GSPE) on the viability of abdominal skin flaps exposed to warm ischaemia and subsequent reperfusion were studied in 40 male Wistar rats. In the control group (group I; n=20), rats were fed with standard, non-purified rat diet, and the study group received GSPE 100 mgkg(-1) per day 1 week prior to surgery and 1 week following surgery. Abdominal island flaps were elevated in both the groups and subjected to 8h of warm ischaemia, followed by reperfusion. Mean flap survival areas in groups I (control group) and II (treatment group) were calculated to be 58.3%+/-11.72 and 81.0%+/-11.88, respectively. Flap survival on day 7 was significantly higher in group II compared to group I (p<0.01). Histopathological semi-quantitative analysis of the specimens revealed infiltration by polymorphonuclear leucocytes, oedema formation and necrosis in group I, whereas neo-vascularisation and fibrosis were the prominent findings in group II.

Liquid chromatography tandem mass spectrometry identification of proanthocyanidins in rat plasma after oral administration of grape seed extract

Proanthocyanidin rich plant extracts derived from grape seed extract (GSE), hawthorn and cranberry are on markets for their preventive effects against cardiovascular diseases and uroinfections in woman. However, the importance of these health beneficial effects of these botanicals remains elusive due to incomplete understanding of uptake, metabolism and bioavailability of proanthocyanidins in vivo. In the present study rats were given GSE orally (300 mg/kg, twice a day) and blood and urine were collected over a 24 h period. Monomeric catechins and their methylated metabolites, and proanthocyanidins up to trimers were detected in blood samples treated with GSE using LC-MS/MS operating in the multiple reaction monitoring (MRM) mode. A new tetramethylated metabolite of dimeric proanthocyanidin (m/z 633) in GSE-treated urine was tentatively identified. Using LC-MS/MS, (+)-catechin and (-)-epicatechin were identified in the brain conclusively. These data suggested that GSE catechins cross the blood brain barrier and may be responsible for the neuroprotective effects of GSE.

Effect of Proanthocyanidin-Rich Extract from Grape Seeds on Human Fecal Flora and Fecal Odor

The aim of this study was to evaluate the effects of proanthocyanidin-rich extracts from grape seeds on human fecal  ora and fecal odor. Proanthocyanidin-rich extract containing 38.5% proanthocyanidin was administered to nine healthy adults at a dose of 0.5 g/day (0.19 g/day as proanthocyanidin) for 2 weeks, and proanthocyanidin-rich extract containing 89.3% proanthocyanidin was administered to eight elderly inpatients at a dose of 0.43 g/day (0.38 g/day as proanthocyanidin) for 2 weeks. Green tea extract and/or champignon extract, both of which have been found to have a deodorant effect on fecal odor, were administered in a similar manner as controls. In healthy adults, marked decreases in fecal odor and concentrations of methyl mercaptan and hydrogen sul. de in feces were observed during proanthocyanidin-rich extract intake, but the effects of green tea extract and champignon extract were weak. After 2 weeks of proanthocyanidin-rich extract intake, the number of Bifidobacterium had increased significantly (p<0.05), whereas the number of Enterobacteriaceae tended to decrease ( p =0.121). The level of putrefactive substances, including ammonia, phenol, p -cresol, 4-ethylphenol, indole, and skatols tended to decrease after proanthocyanidin-rich extract intake, and fecal pH also tended to decrease. Nurses and hospital aides performed organoleptic evaluations that showed less fecal odor in elderly inpatients with proanthocyanidin-rich extract intake than with champignon extract intake. In an in vitro study, the proanthocyanidin-rich extract reduced methyl mercaptan and hydrogen sul. de release from the feces of healthy adults, and also reduced methyl mercaptan release from methyl mercaptan solution. The absorptive ability of methyl mercaptan was stronger in procyanidin oligomers larger than decamer than procyanidin dimer to tetramer. These results suggest that proanthocyanidin-rich extract from grape seed intake induces a reduction in the level of putrefactive products in the intestine, which may be linked to the modest change in the numbers of Bifidobacterium and Enterobacteriaceae . They also suggest that the strong deodorant effect of proanthocyanidins on fecal odor is due to the decrease of putrefactive products and the absorption of malodorous compounds from feces by the larger molecular procyanidin oligomers in the proanthocyanidins. Keywords : proanthocyanidin, grape seed extract, polyphenol, fecal  ora, fecal odor.

Proanthocyanidin-rich extract from grape seeds attenuates the development of aortic atherosclerosis in cholesterol-fed rabbits

The aim of this study was to evaluate the antiatherosclerotic effect of proanthocyanidin-rich extracts from grape seeds in cholesterol-fed rabbits. Proanthocyanidin-rich extracts (0.1% and 1% in diets [w/w]) did not appreciably affect the changes in serum lipid profile of cholesterol-fed rabbits. The level of cholesteryl ester hydroperoxides (ChE-OOH) induced by 2,2′-azobis(2-amidinopropane-dihydrochloride (AAPH) were lower in the plasma of rabbits fed proanthocyanidin-rich extract plus cholesterol than in the plasma of rabbits fed cholesterol alone, but not in the low-density lipoprotein (LDL). Aortic malondialdehyde (MDA) content decreased in rabbits fed proanthocyanidin-rich extract. Feeding proanthocyanidin-rich extracts (0.1 and 1% in the diet) to rabbits significantly reduced severe atherosclerosis in the aorta. Immunohistochemical analysis revealed a decrease in the number of oxidized LDL-positive macrophage-derived foam cells in atherosclerotic lesions in the aorta of rabbits fed proanthocyanidin-rich extract. When proanthocyanidin-rich extract was administered orally to rats, proanthocyanidin was detected in the plasma by Porters method but not in the lipoproteins (LDL plus VLDL). In an in vitro experiment using human plasma, proanthocyanidin-rich extract added to the plasma inhibited the oxidation of cholesteryl linoleate in LDL, but not in the LDL isolated after the plasma and the extract were incubated in advance. These results suggested that proanthocyanidins, the major polyphenols in red wine, might trap reactive oxygen species in aqueous series such as plasma and interstitial fluid of the arterial wall, thereby inhibiting oxidation of LDL and showing an antiatherosclerotic activity.

Isolation, characterisation and determination of biological activity of coffee proanthocyanidins

Abstract: Two proanthocyanidin-containing preparations were isolated from thepulp of ripe Co†ea canephora co†ee cherries. The preparations were partiallypuriÐed by Sephadex LH-20 column chromatography and characterised bymeans of infrared and 13C NMR spectroscopy, and reactions with several func-tional group-speciÐc reagents. These proanthocyanidin-rich extracts from co†eepulp, obtained also from co†ee leaves, inhibit the germination in vitro of Hemi-leia vastatrix race 2 uredospores. Greater proanthocyanidin content was associ-ated with greater potency, and the leaves of Co†ea arabica, a co†ee speciessusceptible to rust, contained less proanthocyanidins than the leaves of C canep-hora, a rust-resistant co†ee. 1998 SCI.(J Sci Food Agric 77, 368E372 (1998)Key words: co†ee pulp; proanthocyanidins; condensed tannins; antifungal activ-ity; co†ee rust; Hemileia vastatrix INTRODUCTIONPhenolic compounds are some of the most widespreadmolecules in nature. They are especially associated withplants where they are found as simple phenols, phenolicacids, hydroxycinnamic acids derivatives, Navonoidsand tannins (Ho 1992). Tannins have relatively largemolecular mass and complex strongly with carbo-hydrates and proteins (Porter 1989). Several tannin sub-groups are known: one of these, condensed tannins or