Viburnum opulus L. Juice Phenolics Inhibit Mouse 3T3-L1 Cells Adipogenesis and Pancreatic Lipase Activity

Gilaburu (Viburnum opulus L.) fruit extract has potential therapeutic and prophylactic role in a rat model of acetic acid-induced oxidant colonic damage

ETHNOPHARMACOLOGICAL RELEVANCE

Ulcerative colitis (UC) which has a global impact on the health care system with its recurrent and incompletely curable characteristics, affects the patients' quality of life. Gilaburu (GB; Viburnum opulus L.) is a fruit with rich polyphenol ingredient which is used ethnobotanically in Türkiye for medicinal purposes (for example, to pass kidney stones, to treat stomach, heart, and liver diseases, hemorrhages, hypertension, ulcers, common cold, tuberculosis, rheumatic and menstrual pain, and diabetes). On the other hand, the effects of GB in the experimental UC model have not been studied.

AIM OF THE STUDY

This study aimed to explore the potential antioxidant and anti-inflammatory effects of GB fruit extract in improving acetic acid (AA)-induced UC.

MATERIALS AND METHODS

Starting immediately after (AA + GB group) or 1 week before (GB + AA + GB group) the colitis induced by intrarectal AA (5%; v/v) administration, the rats orally received GB (100 mg/kg) once per day for 3 days. The control and AA groups were administered orally saline (1 ml), while the AA + SS group were administered sulfasalazine (SS; 100 mg/kg; orally) as a positive control once per day for 3 days. Distal colonic tissue specimens were obtained for the histological and biochemical [myeloperoxidase (MPO), malondialdehyde (MDA), glutathione (GSH), chemiluminescence (CL), caspase-3, 8-hydroxy-2'-deoxyguanosine (8-OHdG), matrix metalloproteinase (MMP)-9, transforming growth factor (TGF)-β1, smad-3 and cytokine (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, IL-8, interferon (IFN)-γ), measurements] evaluations on the 3rd day.

RESULTS

Elevated macroscopic and microscopic damage scores, high tissue wet weight values, increased tissue-associated MPO, MDA, CL, caspase-3, 8-OHdG, cytokines (TNF-α, IL-1β, IL-6, IL-8), MMP-9, TGF-β1, smad-3 levels, and decreased GSH values of the AA group were all reversed by GB treatments (AA + GB and GB + AA + GB groups) (p < 0.05-0.001). However, sulfasalazine treatment (AA + SS group) did not change the IL-8, 8-OHdG, MMP-9, and TGF-β1 measurements significantly.

CONCLUSIONS

Gilaburu shows both anti-inflammatory and antioxidant effects against AA-induced colonic damage by suppressing neutrophil infiltration, regulating inflammatory mediators, inhibiting reactive species production, lipid peroxidation, and apoptosis, conserving endogenous antioxidant glutathione, and ameliorating oxidative DNA damage. Since the current ulcerative colitis drugs display limited benefits and adverse side effects, potential therapeutic and/or prophylactic role of gilaburu can be evaluated in ulcerative colitis.

Natural compounds against nonalcoholic fatty liver disease: A review on the involvement of the LKB1/AMPK signaling pathway

Although various therapeutic approaches are used to manage nonalcoholic fatty liver disease (NAFLD), the best approach to NAFLD management is unclear. NAFLD is a liver disorder associated with obesity, metabolic syndrome, and diabetes mellitus. NAFLD progression can lead to cirrhosis and end-stage liver disease. Hepatic kinase B1 (LKB1) is an upstream kinase of 5'-adenosine monophosphate-activated protein kinase (AMPK), a crucial regulator in hepatic lipid metabolism. Activation of LKB1/AMPK inhibits fatty acid synthesis, increases mitochondrial β-oxidation, decreases the expression of genes encoding lipogenic enzymes, improves nonalcoholic steatohepatitis, and suppresses NAFLD progression. One potential opening for new and safe chemicals that can tackle the NAFLD pathogenesis through the LKB1-AMPK pathway includes natural bioactive compounds. Accordingly, we summarized in vitro and in vivo studies regarding the effect of natural bioactive compounds such as a few members of the polyphenols, terpenoids, alkaloids, and some natural extracts on NAFLD through the LKB1/AMPK signaling pathway. This manuscript may shed light on the way to finding a new therapeutic agent for NAFLD management.

Safety assessment of European cranberrybush (Viburnum opulus L.) fruit juice: Acute and subacute oral toxicity

European cranberrybush (ECB) (Viburnum opulus L.) fruits are abundant in phenolic compounds associated with various health benefits. However, the toxicity and safety of ECB juice have not been systematically studied. In the present study, acute and subacute oral toxicities of ECB fruit juice were evaluated on Sprague-Dawley rats and BALB/c mice to establish a toxicity profile. In acute tests, a single administration of 2000 mg/kg body weight of extract to rats exhibited no clinical signs of toxicity or mortality, indicating that the lethal dose (LD50) was over 2000 mg/kg. In subacute tests, repeated administration for 28 days at 0 (control), 500, and 2000 mg/kg doses of extract in mice did not display adverse clinical signs or deaths. However, in the 2000 mg/kg subacute group, platelet counts were significantly high, which correlated with histopathological analyses revealing that ECB extract at 2000 mg/kg was toxic to the kidney, liver, and adipose tissue. The NOAEL value of ECB extract was found as 500 mg/kg/day, but further sub-chronic and chronic toxicity studies are warranted to comprehensively evaluate the long-term safety implications. The study's results emphasize the importance of considering the dosage of dietary supplements containing high levels of phenolic compounds over an extended period to avoid potential cumulative effects from prolonged consumption of high doses.

A mix of ginger phenols exhibits anti‑adipogenic and lipolytic effects in mature adipocytes derived from 3T3‑L1 cells

The prevalence of obesity has increased rapidly worldwide. Obesity is characterized by excessive adipose tissue in the body, which is related to hyperplasia and hypertrophy in adipocytes. Ginger (Zingiber officinale Roscoe) is a medicinal plant that possesses an anti-obesogenic effect mostly attributed to gingerols, the most abundant bioactive compounds in ginger. The anti-adipogenic and lipolytic effects of these phenols have been shown when investigated individually. Therefore, the present study aimed to evaluate the lipolytic and anti-adipogenic activity of a mix of the main ginger phenols 6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 8-shogaol and 10-shogaol on the 3T3-L1 cell line. A total of four study groups were designed: Negative control (3T3-L1 preadipocytes); positive control (mature 3T3-L1 adipocytes); phenols-pre (3T3-L1 cells stimulated with the phenols mix during adipogenic differentiation); and phenols-post (mature 3T3-L1 adipocytes stimulated with the phenols mix). MTT viability cell assay and Oil Red O staining were performed. Glycerol concentration supernatants were determined using the VITROS 350 Chemistry System. Expression of mRNA was measured using qPCR. The treatment with a 2 µg/ml ginger phenol dose reduced the lipid content by 45.52±7.8 and 35.95±0.76% in the phenols-pre and -post group, respectively, compared with that in the positive control group. The phenols-post group presented a higher glycerol concentration in the supernatant compared with that in the positive control and the phenols-pre groups. The mRNA expression levels of CCAAT/enhancer-binding protein alpha, peroxisome proliferator activated receptor-γ, fatty acid-binding protein 4 and fatty acid synthase were higher in the phenols-pre and lower in the phenols-post groups, compared with those in the positive control group. To the best of our knowledge, the current study demonstrated for the first time the anti-adipogenic and lipolytic effects of a mix of the main bioactive compounds found in ginger, and it also established the basis to use this mix of phenols in in vivo studies and clinical trials.

Flavonoids and Phenolic Acids Content in Cultivation and Wild Collection of European Cranberry Bush Viburnum opulus L

Guelder rose (Viburnum opulus L.) is known for its health benefits. V. opulus contains phenolic compounds (flavonoids and phenolic acids), a group of plant metabolites with wide biological activities. They are good sources of natural antioxidants in human diets owing to their prevention of the oxidative damage responsible for many diseases. In recent years, observations have shown that an increase in temperature can change the quality of plant tissues. So far, little research has addressed the problem of the common impact of temperature and place of occurrence. Towards a better understanding of phenolics concentration that could indicate their potentials as therapeutic agents and towards predicting and controlling the quality of medicinal plants, the aim of this study was to compare phenolic acids and flavonoids content in the leaves of cultivation and wild collection V. opulus, and to examine the impacts of temperature and place of occurrence on their content and composition. Total phenolics were determined using the spectrophotometric method. Phenolic composition of V. opulus was determined using high-performance liquid chromatography (HPLC). The following hydroxybenzoic acids there were identified: gallic, p-hydroxybenzoic, syringic, salicylic, benzoic, as well as hydroxycinnamic acids: chlorogenic, caffeic, p-coumaric, ferulic, o-coumaric and t-cinnamic. The analysis of extracts from V. opulus leaves has indicated the presence of the following flavonoids: flavanols: (+)-catechin and (-)-epicatechin; flavonols: quercetin, rutin, kaempferol, myricetin; and flavones: luteolin, apigenin and chrysin. The dominant phenolic acids were p-coumaric and gallic acids. The major flavonoids found in V. opulus leaves were myricetin and kaempferol. Temperature and plant location affected the concentration of tested phenolic compounds. The present study shows the potential of naturally grown and wild V. opulus for the human.

Hulless barley polyphenol extract inhibits adipogenesis in 3T3-L1 cells and obesity related-enzymes

Obesity is characterized by excessive lipid accumulation, hypertrophy, and hyperplasia of adipose cells. Hulless barley (Hordeum vulgare L. var. nudum Hook. f.) is the principal crop grown in the Qinghai-Tibet plateau. Polyphenols, the major bioactive compound in hulless barley, possess antioxidant, anti-inflammatory, and antibacterial properties. However, the anti-obesity effect of hulless barley polyphenol (HBP) extract has not been explored. Therefore, the current study assessed the impact of HBP extract on preventing obesity. For this purpose, we evaluated the inhibitory effect of HBP extract against obesity-related enzymes. Moreover, we investigated the effect of HBP extract on adipocyte differentiation and adipogenesis through 3T3-L1 adipocytes. Our results demonstrated that HBP extract could inhibit α-amylase, α-glucosidase (α-GLU), and lipase in a dose-dependent manner. In addition, HBP extract inhibited the differentiation of 3T3-L1 preadipocytes by arresting the cell cycle at the G0/G1 phase. Furthermore, the extract suppressed the expression of adipogenic transcription factors such as peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), regulating fatty acid synthase (FAS), fatty acid-binding protein 4 (FABP4), and adipose triglyceride lipase (ATGL). It was also observed that HBP extract alleviated intracellular lipid accumulation by attenuating oxidative stress. These findings specify that HBP extract could inhibit obesity-related enzymes, adipocyte differentiation, and adipogenesis. Therefore, it is potentially beneficial in preventing obesity.

Phenolics-Rich Extracts of Dietary Plants as Regulators of Fructose Uptake in Caco-2 Cells via GLUT5 Involvement

The latest data link the chronic consumption of large amounts of fructose present in food with the generation of hypertension and disturbances in carbohydrate and lipid metabolism, which promote the development of obesity, non-alcoholic fatty liver disease, insulin resistance, and type 2 diabetes. This effect is possible after fructose is absorbed by the small intestine cells and, to a lesser extent, by hepatocytes. Fructose transport is dependent on proteins from the family of glucose transporters (GLUTs), among which GLUT5 selectively absorbs fructose from the intestine. In this study, we examined the effect of four phenolic-rich extracts obtained from A. graveolens, B. juncea, and M. chamomilla on fructose uptake by Caco-2 cells. Extracts from B. juncea and M. chamomilla most effectively reduced fluorescent fructose analogue (NBDF) accumulation in Caco-2, as well as downregulated GLUT5 protein levels. These preparations were able to decrease the mRNA level of genes encoding transcription factors regulating GLUT5 expression-thioredoxin-interacting protein (TXNIP) and carbohydrate-responsive element-binding protein (ChREBP). Active extracts contained large amounts of apigenin and flavonols. The molecular docking simulation suggested that some of identified phenolic constituents can play an important role in the inhibition of GLUT5-mediated fructose transport.

Metabolic and Anti-Inflammatory Protective Properties of Human Enriched Serum Following Artichoke Leaf Extract Absorption: Results from an Innovative Ex Vivo Clinical Trial

The aging of our population is accompanied by an increased prevalence of chronic diseases. Among those, liver, joint and adipose tissue-related pathologies have a major socio-economic impact. They share common origins as they result from a dysregulation of the inflammatory and metabolic status. Plant-derived nutrients and especially polyphenols, exert a large range of beneficial effects in the prevention of chronic diseases but require clinically validated approaches for optimized care management. In this study, we designed an innovative clinical approach considering the metabolites produced by the digestive tract following the ingestion of an artichoke leaf extract. Human serum, enriched with metabolites deriving from the extract, was collected and incubated with human hepatocytes, human primary chondrocytes and adipocytes to determine the biological activity of the extract. Changes in cellular behavior demonstrated that the artichoke leaf extract protects hepatocytes from lipotoxic stress, prevents adipocytes differentiation and hyperplasia, and exerts chondroprotective properties in an inflammatory context. These data validate the beneficial health properties of an artichoke leaf extract at the clinical level and provide both insights and further evidence that plant-derived nutrients and especially polyphenols from artichoke may represent a relevant alternative for nutritional strategies addressing chronic disease issues.

The Effect of Simulated In Vitro Digestion on Biological Activity of Viburnum opulus Fruit Juices

In the present study, an in vitro digestion method has been used to assay the influence of the physiological conditions in the mouth, stomach, and intestine on the stability and activity in different cell models of the main phenolic compounds from Viburnum opulus fresh juice (FJ), phenolic-rich juice (PJ), and the bioavailable fractions (DFJ and DPJ). The data obtained indicate that the V. opulus samples achieved after in vitro digestion had an influence on cellular glucose and lipid metabolism. The bioavailable fraction of both digested juices stimulated glucose uptake and decreased lipid accumulation by L6 myoblasts and HepG2 hepatocytes. Both DFJ and DPJ reduced the secretion of inflammatory cytokines by 3T3-L1 adipocytes: interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). Simultaneously, DFJ and DPJ enhanced oxidative stress in MIN6 cells and decreased glucose-stimulated insulin secretion (GSIS). UPLC-MS analysis revealed qualitative and quantitative changes in hydroxycinnamic acids. In particular, the content of chlorogenic acid decreased drastically; its content in the bioavailable fraction was almost 7 times and 30 times lower than in the FJ and PJ, respectively. Our results suggested that although the phenolic compounds of V. opulus juices undergo transformation during digestion, they are still potent antioxidant agents with biological activity.

Glycoside Hydrolases and Non-Enzymatic Glycation Inhibitory Potential of Viburnum opulus L. Fruit-In Vitro Studies

Phytochemicals of various origins are of great interest for their antidiabetic potential. In the present study, the inhibitory effects against carbohydrate digestive enzymes and non-enzymatic glycation, antioxidant capacity, and phenolic compounds composition of Viburnum opulus L. fruits have been studied. Crude extract (CE), purified extract (PE), and ethyl acetate (PEAF) and water (PEWF) fractions of PE were used in enzymatic assays to evaluate their inhibitory potential against α-amylase with potato and rice starch as substrate, α-glucosidase using maltose and sucrose as substrate, the antioxidant capacity (ABTS, ORAC and FRAP assays), antiglycation (BSA-fructose and BSA-glucose model) properties. Among four tested samples, PEAF not only had the highest content of total phenolics, but also possessed the strongest α-glucosidase inhibition, antiglycation and antioxidant activities. UPLC analysis revealed that this fraction contained mainly chlorogenic acid, proanthocyanidin oligomers and flavalignans. Contrary, the anti-amylase activity of V. opulus fruits probably occurs due to the presence of proanthocyanidin polymers and chlorogenic acids, especially dicaffeoylquinic acids present in PEWF. All V. opulus samples have an uncompetitive and mixed type inhibition against α-amylase and α-glucosidase, respectively. Considering strong anti-glucosidase, antioxidant and antiglycation activities, V. opulus fruits may find promising applications in nutraceuticals and functional foods with antidiabetic activity.

Ferulic Acid Stimulates Adipocyte-Specific Secretory Proteins to Regulate Adipose Homeostasis in 3T3-L1 Adipocytes

Obesity has recently emerged as a public health issue facing developing countries in the world. It is caused by the accumulation of fat in adipose, characterized by insulin resistance, excessive lipid accumulation, inflammation, and oxidative stress, leading to an increase in adipokine levels. Herein, we investigated the capacity of a bioactive polyphenolic compound (ferulic acid (FA)) to control adipocyte dysfunction in 3T3-L1 adipocytes (in vitro). Key adipocyte differentiation markers, glycerol content, lipolysis-associated mRNA, and proteins were measured in experimental adipocytes. FA-treated adipocytes exhibited downregulated key adipocyte differentiation factors peroxisome proliferator-activated receptor-γ (PPAR-γ), CCAT enhancer binding-proteins-α (C/EBP-α) and its downstream targets in a time-dependent manner. The FA-treated 3T3-L1 adipocytes showed an increased release of glycerol content compared with non-treated adipocytes. Also, FA treatment significantly up-regulated the lipolysis-related factors, including p-HSL, and p-perilipin, and down-regulated ApoD, Sema3C, Cxcl12, Sfrp2, p-stearoyl-CoA desaturase 1 (SCD1), adiponectin, and Grk5. Also, the FA treatment showed significantly down-regulated adipokines leptin, chemerin, and irisin than the non-treated cells. The present findings indicated that FA showed significant anti-adipogenic and lipogenic activities by regulating key adipocyte factors and enzyme, enhanced lipolysis by HSL/perilipin cascade. FA is considered a potent molecule to prevent obesity and its associated metabolic changes in the future.

An In Vitro Study of the Effect of Viburnum opulus Extracts on Key Processes in the Development of Staphylococcal Infections

Staphylococcus aureus is still one of the leading causes of both hospital- and community-acquired infections. Due to the very high percentage of drug-resistant strains, the participation of drug-tolerant biofilms in pathological changes, and thus the limited number of effective antibiotics, there is an urgent need to search for alternative methods of prevention or treatment for S. aureus infections. In the present study, biochemically characterized (HPLC/UPLC–QTOF–MS) acetonic, ethanolic, and water extracts from fruits and bark of Viburnum opulus L. were tested in vitro as diet additives that potentially prevent staphylococcal infections. The impacts of V. opulus extracts on sortase A (SrtA) activity (Fluorimetric Assay), staphylococcal protein A (SpA) expression (FITC-labelled specific antibodies), the lipid composition of bacterial cell membranes (LC-MS/MS, GC/MS), and biofilm formation (LIVE/DEAD BacLight) were assessed. The cytotoxicity of V. opulus extracts to the human fibroblast line HFF-1 was also tested (MTT reduction). V. opulus extracts strongly inhibited SrtA activity and SpA expression, caused modifications of S. aureus cell membrane, limited biofilm formation by staphylococci, and were non-cytotoxic. Therefore, they have pro-health potential. Nevertheless, their usefulness as diet supplements that are beneficial for the prevention of staphylococcal infections should be confirmed in animal models in the future.

Viburnum opulus L.-A Review of Phytochemistry and Biological Effects

Viburnum opulus (VO) is a valuable decorative, medicinal, and food plant. This deciduous shrub is found in natural habitats in Europe, Russia, and some regions in North Africa and North Asia. The VO is traditionally used to treat aliments such as cough, colds, tuberculosis, rheumatic aches, ulcers, stomach, and kidney problems, among others. Many of the health-promoting properties of VO are associated with antioxidant activity, which has been demonstrated in both in vitro and in vivo studies. The results of in vitro studies show the antimicrobial potential of VO, especially against Gram-positive bacteria. In cell-based studies, VO demonstrated anti-inflammatory, anti-obesity, anti-diabetic, osteogenic, cardio-protective, and cytoprotective properties. The applicability of VO in the treatment of urinary tract diseases, endometriosis, and some cancers has been confirmed in in vivo studies. The health benefits of VO result from the presence of bioactive components such as phenolic compounds, vitamin C, carotenoids, iridoids, and essential oils. The aim of this review is to present an overview of the botanical characteristics, chemical compositions, including bioactive compounds, and pro-health properties of VO different morphological parts.

Inula britannica Inhibits Adipogenesis of 3T3-L1 Preadipocytes via Modulation of Mitotic Clonal Expansion Involving ERK 1/2 and Akt Signaling Pathways

The flower of Inula britannica contains various phenolic compounds with prophylactic properties. This study aimed to determine the anti-adipogenic effect of an I. britannica flower aqueous extract (IAE) and its underlying mechanisms in the 3T3-L1 preadipocytes and to identify the phenolic compounds in the extract. Treatment with IAE inhibited the adipogenesis by showing a dose-dependent suppressed intracellular lipid accumulation and mitigated expression levels of lipogenesis- and adipogenesis-associated biomarkers including transcription factors. IAE exerted an anti-adipogenic effect through the modulation of the early phases of adipogenesis including mitotic clonal expansion (MCE). Treatment with IAE inhibited MCE by arresting the cell cycle at the G0/G1 phase and suppressing the activation of MCE-related transcription factors. Furthermore, IAE inhibited adipogenesis by regulating the extracellular signal-regulated kinase 1/2 and Akt signaling pathways. Protocatechuic acid, chlorogenic acid, kaempferol-3-O-glucoside, and 6-methoxyluteolin, which are reported to exhibit anti-adipogenic properties, were detected in IAE. Therefore, modulation of early phases of adipogenesis, especially MCE, is a key mechanism underlying the anti-adipogenic activity of IAE. In summary, the anti-obesity effects of IAE can be attributed to its phenolic compounds, and hence, IAE can be used for the development of anti-obesity products.

Viburnum opulus L. Juice Phenolic Compounds Influence Osteogenic Differentiation in Human Osteosarcoma Saos-2 Cells

Bone mass loss occurs with a decrease in osteoblast proliferation and differentiation, or the enhancement of bone resorption, which further leads to the impairment of bone mineral density and increase in bone fracture. Recent studies suggest that some phenolic compounds found in food play positive role in bone metabolism. High content of phenolic compounds with potential beneficial effects on bone metabolism have been identified in the Viburnum opulus fruit. The aim of the study was to determine the influence of V. opulus fresh juice (FJ) and juice purified by solid phase extraction (PJ) on osteogenesis processes with osteosarcoma Saos-2 cell lines. V. opulus purified juice revealed stronger potential as an inducer of Saos-2 osteogenic differentiation. Saos-2 cells matrix mineralization was evaluated with alkaline phosphatase (ALP) activity measurement and alizarin red S staining. Gene expression analysis showed the elevation of the mRNA levels of Runt-related transcription factor 2 (RUNX2), ALP, collagen type 1 and osteonectin, whereas the nuclear factor-κB ligand and osteoprotegerin ratio (RANKL/OPG) decreased. Furthermore, V. opulus was able to diminish the secretion of pro-inflammatory cytokines Il6 and TNFα, however had no effect on vascular endothelial growth factor (VEGF). It decreased intracellular oxidative stress and induced DNA repair, but had no effect on the growth inhibition of lactic acid beneficial microorganisms.