Proanthocyanidin derived from the leaves of Vaccinium virgatum suppresses platelet-derived growth factor-induced proliferation of the human hepatic stellate cell line LI90

Procyanidin B2: A promising multi-functional food-derived pigment for human diseases

Natural edible pigments play a paramount part in the food industry. Procyanidin B2 (PB2), one of the most representative naturally occurring edible pigments, is usually isolated from the seeds, fruits, and leaves of lots of common plants, such as grapes, Hawthorn, black soybean, as well as blueberry, and functions as a food additive in daily life. Notably, PB2 has numerous bioactivities and possesses the potential to treat/prevent a wide range of human diseases, such as diabetes mellitus, diabetic complications, atherosclerosis, and non-alcoholic fatty liver disease, and the underlying mechanisms were partially elucidated, including mediating signaling pathways like NF-κB, MAPK, PI3K/Akt, apoptotic axis, and Nrf-2/HO-1. This paper presents a review of the natural sources, bioactivities, and the therapeutic/preventive potential of PB2 and the possible mechanisms, with the aim of promoting the development of PB2 as a functional food and providing references for its clinical application in the treatment of diseases.

Prediction of the Adult T-Cell Leukemia Inhibitory Activity of Blueberry Leaves/Stems Using Direct-Injection Electron Ionization-Mass Spectrometry Metabolomics

Although Vaccinium virgatum Aiton leaves and stems inhibit adult T-cell leukemia (ATL) cells, leaves and stems can differ between individual plants and by time and location. In this study, leaf and stem components were profiled in the same individual plant using direct-injection electron ionization-mass spectrometry (DI-EI-MS) metabolomics, with the aims of analyzing the anti-ATL activity, and quantifying proanthocyanidins (PACs). Leaves, stems, and leaf/stem mixtures showed distinct and characteristic spectra. Anti-ATL activity was stronger in stems than leaves, and the PAC content was higher in stems than leaves. These data were subjected to bivariate analysis to identify the factor (m/z) responsible for the inhibitory effect of ATL based on the highest coefficient of determination (R2). The results of this DI-EI-MS metabolomics analysis suggest that among PACs contained in V. virgatum stems and leaves, the fragment ion at m/z 149 contributes significantly to anti-ATL activity.

Effective Utilization of Vaccinium virgatum Aiton Stems as Functional Materials: Major Constituent Analysis and Bioactivity Evaluation

We previously reported that rabbit-eye blueberry (Vaccinium virgatum Aiton) leaves exhibit multiple functions. In this study, we evaluated whether V. virgatum stems can also be used as functional materials similar to leaves and clarified the major constituents and their biological activity (antioxidant activity and anti–adult T cell leukemia (ATL) activity). Water extracts of V. virgatum stems were separated into 19 fractions using a Diaion HP-20 open column. Sugars and organic acids were detected in the highly water-soluble fractions. Polyphenols and proanthocyanidin were detected in the hydrous methanol-soluble fractions. In biological activity evaluations, a difference in antioxidant activity was observed in the water-containing methanol-eluted fractions, and fractions exhibiting anti-ATL activity differed depending on cell type. These results suggest that blueberry stems, like leaves, are rich in polyphenols and exhibit antioxidant activity and inhibit ATL cell growth. In the future, aerial parts of blueberries, including stems and leaves, could be used as functional materials and/or medicinal resources.

Effects of Croton lechleri sap (Sangre de Drago) on AGEs formation, LDL oxidation and oxidative stress related to vascular diseases

The sap of Croton lechleri Müll. Arg. (Euphorbiaceae) is well-known in South American traditional medicine. This research investigated its activity against glycation and oxidative stress (glycoxidation) to estimate its usefulness in ROS-related diseases. The activity of the sap on albumin glycation, LDL oxidation and ROS formation was detected. C. lechleri sap inhibited BSA glycation and exhibited a protective effect against LDL oxidation; at the concentration of 0.8 µg/mL, it extended the Lag phase of almost 60%. Furthermore, the sap was studied on cell viability and ROS production in HUVEC showing valuable free-radical scavenging activity. In detail, the sap (1.0 and 10.0 μg/mL) significantly decreased the baseline level and H₂O₂-induced ROS production in HUVEC. This research showed for the first time the ability of C. lechleri sap to decrease the albumin glycation, LDL oxidation and ROS formation in HUVEC, supporting its potential in vascular diseases.

Chronic intake of high-dose of blueberry leaf extract does not augment the harmful effects of ethanol in rats

Excessive alcohol consumption is a risk factor for liver diseases. Enhancement of alcohol metabolism could be an effective strategy to prevent these adverse effects since it promotes the clearance of ethanol and acetaldehyde from the serum. Polyphenol-rich products have shown to protect against alcohol-related liver damage. Blueberry leaves have attracted attention as they are rich polyphenols such as proantocyanidins and chlorogenic acid. In this study, we investigated the effects of a high dose of blueberry leaf extract (BLEx) on alcohol metabolism during chronic intake of ethanol. Seven-week old Sprague-Dawley (SD) rats were divided into four groups: normal liquid diet group (NLD), normal liquid diet + BLEx group (NLD + BLEx), alcohol liquid diet group (ALD), and alcohol liquid diet + BLEx (ALD + BLEx). Then, rats were fed experimental diet for 5 weeks and at the end of feeding period, body weight, food intake, liver weight, indices of liver injury, expression and activity of alcohol metabolism-related and anti-oxidative enzymes, and levels of carbonyl protein, triglyceride (TG), and total cholesterol (T-Chol) were measured. Body weight and food intake decreased, whereas liver aldehyde dehydrogenase (ALDH) activity, liver microsomal cytochrome P450 2E1 (CYP2E1) protein and mRNA expression, and heme oxygenase 1 (HO-1) mRNA expression were upregulated by ethanol intake. Dietary BLEx, however, did not affect any of these ethanol-related changes. Indices of liver injury, expression and activity of other alcohol metabolism-related enzymes, liver carbonyl protein, TG, and T-Chol levels were not altered by ethanol and BLEx. Thus, chronic BLEx intake does not ameliorate the harmful effects of ethanol.

Anthocyanins inhibit high glucose-induced renal tubular cell apoptosis caused by oxidative stress in db/db mice

Oxidative stress is an important contributory factor resulting the development of kidney injury in patients with diabetes. Numerous in vitro and in vivo studies have suggested that anthocyanins, natural phenols commonly existing in numerous fruits and vegetables, exhibit important antioxidative, anti‑inflammatory and antihyperlipidemic effects; however, their effects and underlying mechanisms on diabetic nephropathy (DN) have not yet been fully determined. In the present study, the regulation of apoptosis metabolism and antioxidative effects exhibited by anthocyanins [grape seed procyanidin (GSPE) and cyanidin‑3‑O‑β‑glucoside chloride (C3G)] were investigated, and the molecular mechanism underlying this process was investigated in vivo and in vitro. GSPE administration was revealed to suppress renal cell apoptosis, as well as suppress the expression of Bcl‑2 in diabetic mouse kidneys. Furthermore, GSPE administration was demonstrated to suppress the expression of thioredoxin interacting protein (TXNIP), in addition to enhancing p38 mitogen‑activation protein kinase (MAPK) and extracellular signal‑regulated kinase 1/2 (ERK1/2) oxidase activity in diabetic mouse kidneys. In vitro experiments using HK‑2 cells revealed that C3G suppressed the generation of HG‑mediated reactive oxygen species, cellular apoptosis, the expression of cleaved caspase‑3 and the Bax/Bcl‑2 ratio; and enhanced the expression of cytochrome c released from mitochondria. Furthermore, treatment with C3G was revealed to suppress the expression of TXNIP, in addition to the phosphorylation of p38 MAPK and ERK1/2 oxidase activity in HK‑2 cells under HG conditions. In addition, treatment with C3G was revealed to attenuate the HG‑induced suppression of the biological activity of thioredoxin, and to enhance the expression of thioredoxin 2 in HK‑2 cells under HG conditions. In conclusion, the present study demonstrated that anthocyanins may exhibit protective effects against HG‑induced renal injury in DN via antioxidant activity.

The effects of blueberry anthocyanins on histone acetylation in rat liver fibrosis

To determine the effects ofanthocyanins from blueberries on hepatic stellate cell (HSCs-T6) and on histone acetylation during liver fibrosis induced by CCl₄ in rats. Fifty male SD rats weighing 180 ± 20g were randomly placed into a control group, a hepatic fibrosis group, a blueberry treatment group, a blueberry intervention group, and a natural recovery group. After the rats were sacrificed, the livers and the liver indexes were measured, and the pathological changes were observed by HE staining and Masson staining. The blood was analyzed for the four indexes of liver fibrosis and liver function; nucleoprotein from liver tissues and karyoplasm were isolated to determine the expression of acH3K9, acH3K14, and acH3K18 by Western blotting.

Compared with the lethal rate of the control group, the median lethal rate of HSCs-T6 cells treated with a the 50μmol/L concentration was 66.94% (P < 0.05). The protein expression on α-SMA, type I collagen, TIMP1 significantly decreased (P < 0.05) following treatment with 50 ug/ml of anthocyanin for 36 h; moreover, the expression of acH3K9, acH3K14 and acH3K18 modification were up-regulated (P < 0.05). Furthermore, compared with the liver in the model group, the liver in the intervention group showed the most obvious improvement (P < 0.01), and its karyoplasm had increased expression of acH3K9, acH3K14 and acH3K18 (P<0.01).

Regulating histone acetylation could improve liver function and liver fibrosis indexes in rats with hepatic fibrosis. The mechanism might be related to certain genes that promote apoptosis, so as to inhibit the effect of anti hepatic fibrosis.

Dietary supplementation of blueberry juice enhances hepatic expression of metallothionein and attenuates liver fibrosis in rats

Aim

To investigate the effect of blueberry juice intake on rat liver fibrosis and its influence on hepatic antioxidant defense.

Methods

Rabbiteye blueberry was used to prepare fresh juice to feed rats by daily gastric gavage. Dan-shao-hua-xian capsule (DSHX) was used as a positive control for liver fibrosis protection. Liver fibrosis was induced in male Sprague-Dawley rats by subcutaneous injection of CCl₄ and feeding a high-lipid/low-protein diet for 8 weeks. Hepatic fibrosis was evaluated by Masson staining. The expression of α-smooth muscle actin (α-SMA) and collagen III (Col III) were determined by immunohistochemical techniques. The activities of superoxide dismutase (SOD) and malondialdehyde (MDA) in liver homogenates were determined. Metallothionein (MT) expression was detected by real-time RT-PCR and immunohistochemical techniques.

Results

Blueberry juice consumption significantly attenuates CCl₄-induced rat hepatic fibrosis, which was associated with elevated expression of metallothionein (MT), increased SOD activity, reduced oxidative stress, and decreased levels of α-SMA and Col III in the liver.

Conclusion

Our study suggests that dietary supplementation of blueberry juice can augment antioxidative capability of the liver presumably via stimulating MT expression and SOD activity, which in turn promotes HSC inactivation and thus decreases extracellular matrix collagen accumulation in the liver, and thereby alleviating hepatic fibrosis.

Intragastric administration of blueberry juice decreases the expression of Toll-like receptors 4 and 9 in rats with immune hepatic fibrosis

AIM: To investigate the effect of blueberry on the expression of Toll-like receptor 4 (TLR4) and toll-like receptor 9 (TLR9) in rats with immune hepatic fibrosis.

METHODS: Sixty healthy Wistar rats were randomly divided into six groups: normal control group (group A), hepatic fibrosis model group (group B), low-, medium-, and high-concentration blueberry groups (groups C, D and E), and Fufang Biejia Ruanganpian group (group F). Hepatic fibrosis was induced in rats of groups B-F by intraperitoneally injecting porcine serum once daily for 12 wk. Simultaneously, rats of groups C-F were intragastrically given blueberry juice or Fufang Biejia Ruanganpian for 12 wk. All rats were sacrificed at the end of the experiment. Liver index was calculated. Pathological changes in the hepatic tissue were evaluated by hematoxylin-eosin (HE) staining. Serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured. The activity of superoxide dismutase (SOD), the contents of malondialdehyde (MDA), hydroxyproline (Hyp) and reduced glutathione (GSH) in liver homogenates were determined. The expression of TLR4 and TLR9 in the liver was detected by Western blot.

RESULTS: There were no significant differences in serum levels of ALT and AST among various groups (F = 4.274, 0.917, both P > 0.05). Compared to group B, the activities of SOD and contents of GSH in liver homogenates were significantly higher (F = 6.662, 61.472, both P < 0.05); liver index and the contents of Hyp and MDA in liver homogenates were significantly lower (F = 3.972, 42.755, 41.265, all P < 0.05); and the degree of hepatic fibrosis was significantly reduced (F = 63.339, P < 0.05) in groups D and E. The expression of hepatic TLR4 and TLR9 in group E was significantly lower than that in group B (F = 6.932, 7.534, both P < 0.05).

CONCLUSION: Higher expression of TLR4 and TLR9 protein may be associated with the occurrence and development of immune hepatic fibrosis. Blueberry has a preventive effect on immune hepatic fibrosis in rats.