Pomegranate husk extract, punicalagin and ellagic acid inhibit fatty acid synthase and adipogenesis of 3T3-L1 adipocyte

Punicalagin, a pomegranate polyphenol sensitizes the activity of antibiotics against three MDR pathogens of the Enterobacteriaceae

BACKGROUND

Multidrug resistance (MDR) in the family Enterobacteriaceae is a perniciously increasing threat to global health security. The discovery of new antimicrobials having the reversing drug resistance potential may contribute to augment and revive the antibiotic arsenal in hand. This study aimed to explore the anti-Enterobacteriaceae capability of bioactive polyphenols from Punica granatum (P. granatum) and their co-action with antibiotics against clinical isolates of Enterobacteriaceae predominantly prevalent in South Asian countries.

METHODS

The Kandhari P. granatum (Pakistani origin) extracts were tested for anti-Enterobacteriaceae activity by agar well diffusion assay against MDR Salmonella enterica serovar Typhi, serovar Typhimurium and Escherichia coli. Predominant compounds of active extract were determined by mass spectrometry and screened for bioactivity by agar well diffusion and minimum inhibitory concentration (MIC) assay. The active punicalagin was further evaluated at sub-inhibitory concentrations (SICs) for coactivity with nine conventional antimicrobials using a disc diffusion assay followed by time-kill experiments that proceeded with SICs of punicalagin and antimicrobials.

RESULTS

Among all P. granatum crude extracts, pomegranate peel methanol extract showed the largest inhibition zones of 25, 22 and 19 mm, and the MICs as 3.9, 7.8 and 7.8 mg/mL for S. typhi, S. typhimurium and E. coli, respectively. Punicalagin and ellagic acid were determined as predominant compounds by mass spectrometry. In plate assay, punicalagin (10 mg/mL) was active with hazy inhibition zones of 17, 14, and 13 mm against S. typhi, S. typhimurium and E. coli, respectively. However, in broth dilution assay punicalagin showed no MIC up to 10 mg/mL. The SICs 30 μg, 100 μg, and 500 μg of punicalagin combined with antimicrobials i.e., aminoglycoside, β-lactam, and fluoroquinolone act in synergy against MDR strains with % increase in inhibition zone values varying from 3.4 ± 2.7% to 73.8 ± 8.4%. In time-kill curves, a significant decrease in cell density was observed with the SICs of antimicrobials/punicalagin (0.03-60 μg/mL/30, 100, 500 μg/mL of punicalagin) combinations.

CONCLUSIONS

The P. granatum peel methanol extract exhibited antimicrobial activity against MDR Enterobacteriaceae pathogens. Punicalagin, the bacteriostatic flavonoid act as a concentration-dependent sensitizing agent for antimicrobials against Enterobacteriaceae. Our findings for the therapeutic punicalagin-antimicrobial combination prompt further evaluation of punicalagin as a potent activator for drugs, which otherwise remain less or inactive against MDR strains.

Monoterpenoid Glycosides from the Leaves of Ligustrum robustum and Their Bioactivities (II)

Ligustrum robustum has been not only used as a heat-clearing and detoxicating functional tea (Ku-Ding-Cha) but also consumed as a hypotensive, anti-diabetic, and weight-reducing folk medicine. From the leaves of L. robustum, ten new monoterpenoid glycosides named ligurobustosides T10 (1a), T11 (1b), T12 (2a), T13 (2b), T14 (3a), T15 (3b), F1 (4b), T16 (5a), T17 (5b), and E1 (6b), together with five known ones (4a, 6a, 7, 8a, 8b), were separated and identified using the spectroscopic method and chemical method in this research. The results of biological tests exhibited that the fatty acid synthase (FAS) inhibitory action of compound 5 (IC50: 4.38 ± 0.11 μM) was as strong as orlistat (IC50: 4.46 ± 0.13 μM), a positive control; the α-glucosidase inhibitory actions of compounds 1-4 and 7-8, and the α-amylase inhibitory actions of compounds 1-8 were medium; the ABTS radical scavenging capacities of compounds 1-3 and 5-8 (IC50: 6.27 ± 0.23 ~ 8.59 ± 0.09 μM) were stronger than l-(+)-ascorbic acid (IC50: 10.06 ± 0.19 μM) served as a positive control. This research offered a theoretical foundation for the leaves of L. robustum to prevent diabetes and its complications.

Kinetic Ultrasound-Assisted Extraction as a Sustainable Approach for the Recovery of Phenolics Accumulated through UVA Treatment in Strawberry By-Products

Ultrasound-assisted extraction (UAE) is an efficient and sustainable method for extracting bioactive compounds from agro-industrial by-products. Moreover, it has been reported that ultraviolet A (UVA) radiation can induce the biosynthesis and accumulation of bioactive phenolic compounds. This study optimized the efficiency of ultrasound-assisted extraction (UAE) for recovering ultraviolet A (UVA)-induced phenolic compounds in strawberry by-products (RF-N). The impact of three factors (solid-liquid ratio, ethanol concentration, and ultrasound power) on total phenolic compound (TPC) kinetics using Peleg's model was investigated. The developed model showed a suitable fit for both RF-N and strawberry by-products treated with UVA (RF-E). The optimal UAE conditions obtained were of a 1:30 ratio, 46% ethanol, and 100% ultrasound power, resulting in an average yield of 13 g total phenolics kg-1. The bioaccessibility of phenolic compounds during in-vitro digestion was 36.5%, with agrimoniin being the predominant compound. UAE combined with UVA treatment increased the bioactivity of RF extracts, displaying significant anti-proliferative effects on HT29 and Caco-2 cancer cell lines, as well as anti-inflammatory potential and cellular antioxidant activity. The ultrasound proved to be a sustainable and effective technique for extracting phenolic compounds from RF, contributing to the valorization of strawberry agro-industrial by-products, and maximizing their nutraceutical potential.

Chemical Constituents from the Leaves of Ligustrum robustum and Their Bioactivities

The leaves of Ligustrum robustum have been consumed as Ku-Ding-Cha for clearing heat and removing toxins, and they have been used as a folk medicine for curing hypertension, diabetes, and obesity in China. The phytochemical research on the leaves of L. robustum led to the isolation and identification of two new hexenol glycosides, two new butenol glycosides, and five new sugar esters, named ligurobustosides X (1a), X₁ (1b), Y (2a), and Y₁ (2b) and ligurobustates A (3a), B (3b), C (4b), D (5a), and E (5b), along with seven known compounds (4a and 6-10). Compounds 1-10 were tested for their inhibitory effects on fatty acid synthase (FAS), α-glucosidase, and α-amylase, as well as their antioxidant activities. Compound 2 showed strong FAS inhibitory activity (IC₅₀ 4.10 ± 0.12 μM) close to that of the positive control orlistat (IC₅₀ 4.46 ± 0.13 μM); compounds 7 and 9 revealed moderate α-glucosidase inhibitory activities; compounds 1-10 showed moderate α-amylase inhibitory activities; and compounds 1 and 10 displayed stronger 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) ammonium salt (ABTS) radical scavenging effects (IC₅₀ 3.41 ± 0.08~5.65 ± 0.19 μM) than the positive control l-(+)-ascorbic acid (IC₅₀ 10.06 ± 0.19 μM). This study provides a theoretical foundation for the leaves of L. robustum as a functional tea to prevent diabetes and its complications.

Phenylethanoid and Phenylmethanoid Glycosides from the Leaves of Ligustrum robustum and Their Bioactivities

The phytochemical study on the leaves of Ligustrum robustum, which have been used as Ku-Ding-Cha, led to the isolation and identification of three new phenylethanoid glycosides and three new phenylmethanoid glycosides, named ligurobustosides R₁ (1b), R_2-3 (2), R₄ (3), S₁ (4b), S₂ (5), and S₃ (6), and five reported phenylethanoid glycosides (7-11). In the bioactivity test, (Z)-osmanthuside B₆ (11) displayed strong fatty acid synthase (FAS) inhibitory activity (IC₅₀: 4.55 ± 0.35 μM) as the positive control orlistat (IC₅₀: 4.46 ± 0.13 μM), while ligurobustosides R₄ (3) and S₂ (5), ligupurpuroside B (7), cis-ligupurpuroside B (8), ligurobustoside N (9), osmanthuside D (10), and (Z)-osmanthuside B₆ (11) showed stronger ABTS radical scavenging activity (IC₅₀: 2.68 ± 0.05~4.86 ± 0.06 μM) than the positive control L-(+)-ascorbic acid (IC₅₀: 10.06 ± 0.19 μM). This research provided a theoretical basis for the leaves of L. robustum as a tea with function in treating obesity and diabetes.

Peanut Shell Extract and Luteolin Regulate Lipid Metabolism and Induce Browning in 3T3-L1 Adipocytes

Peanut shells are agricultural waste products that require utilization. The freeze-dried ethanolic peanut shell extract (PSE) contained 10.01 ± 0.55 mg/g of luteolin (LUT) with a total polyphenol content of 18.11 ± 0.88 mg GAE/g. Thus, LUT is one of the major polyphenolic components in PSE. Although PSE displays antibacterial and neurotrophic activities, minimal research is available addressing its potential role in lipid metabolism. This study investigated the role of PSE in terms of inhibiting adipogenesis, accelerating lipolysis, and promoting lipid browning using the 3T3-L1 cell line. Without affecting cell viability, high concentrations of PSE and LUT prevented adipogenesis by reducing the mRNA levels of C/EBPα, PPARγ, and SREBP1-c, and increasing the protein levels of pACC and pAMPK. Moreover, PSE and LUT induced lipolysis by activating lipolytic proteins, and enhanced the protein expressions of the brown adipocyte-specific markers, UCP1, PGC-1α, and SIRT1 in fully differentiated 3T3-L1 adipocytes. Increased mitochondrial biosynthesis provided additional evidence in favor of these findings. Due to their anti-obesity properties, it is proposed that PSE and LUT could be used as potential dietary supplements.

Ellagic acid ameliorates high fructose-induced hyperuricemia and non-alcoholic fatty liver in Wistar rats: Focusing on the role of C1q/tumor necrosis factor-related protein-3 and ATP citrate lyase

AIMS

High-fructose intake (HF) represents an inducible risk factor for non-alcoholic fatty liver disease (NAFLD). Present study aimed to illustrate the effect of HF diet (HFD) on the induction of NAFLD, hyperuricemia and role of ellagic acid as modulator.

MAIN METHODS

Twenty-four adult male albino rats were randomly divided into four groups (6/each). The first group received normal chow diet only while the others received 60 % HFD for 4 weeks and subdivided later into 3 groups. The first and second groups received allopurinol and ellagic acid, respectively while the third group received HFD only for extra 4 weeks.

KEY FINDINGS

Rats fed on HFD for 8 weeks displayed body weight gain, insulin resistance (IR), hyperglycemia, dyslipidemia, hyperuricemia with increased oxidative stress and hepatic lipogenic enzymes such as ATP citrate lyase (ACL), aldolase B, and fatty acid synthase (FAS), sterol regulatory element-binding protein 1 (SERBP-1c). C1q /tumor necrosis factor-related protein -3 (CTRP3), and phosphorylated AMP-activated protein kinase (p-AMPK) however showed significant decreases. Ellagic acid or allopurinol administration significantly decreased serum lipids, uric acid, glucose, insulin levels and hepatic contents of enzymes. Malondialdehyde (MDA), FAS, aldolase B, SERBP-1c, and xanthine oxidase (XO) hepatic contents showed significant decreases along with glutathione (GSH) increase as compared to fructose group where ellagic acid was more remarkable compared to allopurinol.

SIGNIFICANCE

Our findings indicated that ellagic acid had alleviated HFD-induced hyperuricemia, its associated NAFLD pattern as mediated through activation of CTRP3 and inhibition of ACL activities in a pattern more remarkable than allopurinol.

Monoterpenoid Glycosides from the Leaves of Ligustrum robustum and Their Bioactivities

The leaves of Ligustrum robustum have been applied as Ku-Ding-Cha, a functional tea to clear heat, remove toxins, and treat obesity and diabetes, in Southwest China. The phytochemical research on the leaves of L. robustum led to the isolation and identification of eight new monoterpenoid glycosides (1–8) and three known monoterpenoid glycosides (9–11). Compounds 1–11 were tested for the inhibitory activities on fatty acid synthase (FAS), α-glucosidase, α-amylase, and the antioxidant effects. Compound 2 showed stronger FAS inhibitory activity (IC₅₀: 2.36 ± 0.10 μM) than the positive control orlistat (IC₅₀: 4.46 ± 0.13 μM), while compounds 1, 2, 5 and 11 displayed more potent ABTS radical scavenging activity (IC₅₀: 6.91 ± 0.10~9.41 ± 0.22 μM) than the positive control L-(+)-ascorbic acid (IC₅₀: 10.06 ± 0.19 μM). This study provided a theoretical basis for the leaves of L. robustum as a functional tea to treat obesity.

Pomegranate peel polyphenols interaction with intestinal flora and its metabolic transformation

1. Pomegranate peel polyphenols (PPPs) have anti-oxidation, anti-atherosclerosis, anti-obesity effect, and so on. However, few studies have been conducted on the absorption and transformation of pomegranate polyphenols in the gut and the biologically active forms that ultimately work in the body.2. In this study, PPPs (300 mg/kg/day) were given to normal rats and relatively sterile rats by gavage respectively. The relatively sterile rats were obtained by neomycin sulfate (250 mg/kg/day) gavage to rats. The purpose of this study is to elaborate the relationship between intestinal flora and polyphenol metabolism of pomegranate peel, and to quantitatively analyze the transformation process of its metabolite urolithin in rats.3. The results showed that decreased bacterial diversity could significantly reduce the abundance of PPPs metabolites in feces and urine in relatively sterile rats. PPPs can regulate intestinal flora structure, significantly enhance the content of Clostrida Firmicutes (P < 0.05), and effectively promote acetic acid, propionic acid, butyric acid, iso-butyric acid and valeric acid production in rat (P < 0.05 or P < 0.01 or P< 0.001). PPPs can significantly elevate the relative proportion of Ruminococcaceae (P < 0.05). Ruminococcaceae_NK4A214_group, Ruminococcaceae_UCG-014 and Ruminococcaceae_UCG-005 can promote the metabolic transformation of PPPs and make the utilization of Urolithin A more effective.

A nascent protein labeling strategy disclosed mitochondrial proteomic responses in punicalagin intervened insulin resistance of HepG2 cells

Insulin resistance (IR), as a common pathophysiological basis, is closely related to a variety of metabolic diseases, such as obesity and diabetes. IR is often accompanied by mitochondrial dysfunction which could be induced by a high fat diet. Punicalagin (PU), a natural compound extracted from pomegranate, could ameliorate palmitate-induced IR. However, the underlying mechanisms are not well known. We propose that understanding the proteomic response of mitochondria may help define the mechanisms of PU in the prevention of IR. Most of the mitochondrial proteins are encoded by nuclear genes and transported from cytoplasm. To distinguish newly incorporated proteins responding to stimuli from pre-existing mitochondrial proteome, nascent proteins in HepG2 cells were pulse labeled by an amino acid analog L-azidohomoalanine. Nascent nuclear encoded mitochondrial proteins were enriched by click reaction followed by mass detection. Our data showed that PU increased nuclear encoded protein incorporation to mitochondria in general though the total protein levels remained immobile. To decipher this phenomenon, we tested the protein and mRNA levels of genes related to mitophagy and mitochondrial biogenesis and found that the mitochondrial turnover was accelerated by PU treatment. By the nascent protein labeling strategy and pathway analysis, we enriched the newly incorporated proteins of mitochondria for responding to PU treatment and found that PU induced nascent protein incorporation into mitochondria and enhanced mitochondrial turnover. These findings demonstrate that PU prevents IR by targeting mitochondria, and thus, is an effective natural nutrient beneficial for mitochondrial turnover.

Therapeutic Potential of Pomegranate in Metabolic Disorders

Metabolic syndrome and associated disorders have become one of the major challenging health problems over the last decades. Considerable attention has been paid to natural products and herbal medicines for the management of metabolic disorders in recent years. Many studies have investigated the therapeutic effects of different parts (arils, peels, seeds, and flowers) of pomegranate (Punica granatum L.) for the prevention and treatment of this syndrome. This study aims to provide an updated review on the in vitro and in vivo studies as well as clinical trials investigating the effects of pomegranate and its active compounds on different components of metabolic problems such as hyperglycemia, hyperlipidemia, hypertension, as well as obesity over the last two decades. Besides, the key mechanisms by which pomegranate affects these pathogenic conditions are also discussed. The studies show that although pomegranate has promising beneficial effects on diabetes, hypertension, hyperlipidemia, and obesity in various cellular, animal, and clinical models of studies, there are some conflicting results, particularly for hyperglycemic conditions. The main mechanisms include influencing oxidative stress and anti-inflammatory responses. Overall, pomegranate seems to have positive effects on the pathogenic conditions of metabolic syndrome according to the reviewed studies. Although pomegranate is not suggested as the first line of therapy or monotherapy, it could be only used as an adjunctive therapy. Nevertheless, further large and long-term clinical studies are still required.

Ongoing and potential novel trends of pomegranate fruit peel; a comprehensive review of its health benefits and future perspectives as nutraceutical

Pomegranate is an ancient shrub, globally distributed nowadays. It has been used in the middle east as a medicinal food and traditional medicine for thousands of years. Pomegranate peel (PP) constitutes about 50% of the total fruit, however, it has been previously regarded as a waste. Recent research points to PP as a rich source of phenolics (e.g., ellagitannins, flavonoids, and anthocyanins), polysaccharides, in addition to its biotransformed metabolites viz. urolithins making it a valuable waste with promising pharmacological actions. Compared to the pulp and the juice, PP exhibited stronger antioxidant and antimicrobial activities. Besides, it inhibited inflammation in several conditions, including colitis, arthritis, hepatitis, contact dermatitis, and lung inflammation. Moreover, it displayed anti-osteoporosis, anti-hyperglycemic, antidiabetic, antihypertensive, vasculoprotective, hepatoprotective, neuroprotective, and immunomodulatory effects. Additionally, it was effective as a prebiotic and in obesity control, besides it promoted wound healing. Furthermore, PP demonstrated anticancer effects against different cancer types, for example, colon, liver, thyroid, uterine, breast, bladder, prostate, leukemia, and osteosarcoma. Despite PP safety, it may interfere with the metabolism of other drugs because it inhibits cytochromes (CYP) changing their bioavailability, effectiveness, and toxicity. PP biowaste valorization not only avoids against its environmental and economic burden but can also provide a promising platform to produce novel or improved nutraceuticals. This study provides a comprehensive overview of PP biological activities with the reported action mechanisms related to its phytochemicals and further biotransformed metabolites inside the body. Future research prospects to unravel the merits of such waste and optimize its use are discussed. PRACTICAL APPLICATION: Pomegranate is widely distributed throughout the world. Although its peel was previously considered a waste, recent research regards it as a rich source of bioactive compounds with promising biological activities. Its recycling not only overcomes the bio-waste problems, but also provides a source of valuable compounds with several health benefits. In recent years, PP has been demonstrated to exhibit excellent pharmacological bioactivities, for example, antioxidant, anti-inflammatory, antimicrobial, antiosteoporosis, antihyperlipidemic, and anticancer activities. Its health-promoting power is mostly attributed to the phenolic and polysaccharide content, in addition to its amazing biotransformed metabolites. The underlying action mechanisms of such pharmacological activities are discussed and related to its chemical content. This review presents the latest research progress on the role of PP in the prevention and treatment of various chronic diseases, and its protective health effects for future research to be used in nutraceuticals.

Physiological and Immune Functions of Punicalagin

The aim of this publication is to compile a summary of the findings regarding punicalagin in various tissues described thus far in the literature, with an emphasis on the effect of this substance on immune reactions. Punicalagin (PUN) is an ellagitannin found in the peel of pomegranate (Punica granatum). It is a polyphenol with proven antioxidant, hepatoprotective, anti-atherosclerotic and chemopreventive activities, antiproliferative activity against tumor cells; it inhibits inflammatory pathways and the action of toxic substances, and is highly tolerated. This work describes the source, metabolism, functions and effects of punicalagin, its derivatives and metabolites. Furthermore, its anti-inflammatory and antioxidant effects are described.

Polyphenols and avenanthramides extracted from oat (Avena sativa L.) grains and sprouts modulate genes involved in glucose and lipid metabolisms in 3T3 L1 adipocytes

This study aimed to evaluate the effect of polyphenol (PE) and avenanthramide (AE) extracts from oat grains (OG) and sprouts (OS) on genes related to glucose and lipid metabolisms in 3T3 L1 adipocytes. The AE-OS exerted the greatest effect on genes involved in glucose metabolism, increasing Glut4, Irs1, and Pi3k expression by 3.0- to 3.9-fold. Conversely, the PE-OS exerted the greatest effect on genes involved in lipid metabolism, decreasing Fasn and Acaca expression by 0.2- to 0.3-fold, and increasing Cpt1a and Acadm expression by 2.7- to 3.0-fold. These effects were mainly related to their high content of avenanthramides A (2p), B (2f), and C (2c), quercetin 3-O-rutinoside, kaempferol, sinapoylquinic acid, and apigenin and luteolin derivatives according to the chemometric analysis. In conclusion, this study demonstrated that oat sprouts extract exerts a greater effect than oat grains on the regulation of genes involved in glucose and lipid metabolisms in adipocytes. PRACTICAL APPLICATIONS: This study demonstrates that polyphenols and avenanthramides extracted from oat (Avena sativa L.) grains and sprouts modulate key genes involved in glucose and lipid metabolisms in adipocytes and that oat sprouts exert a greatest health beneficial effect than oat grains due to their higher content of bioactive compounds. In addition, the chemometric analysis identified the bioactive compounds that can be associated with the beneficial effects of oat grains and sprouts, which can be further used for the identification of oat varieties and oat-derived products with high content of these bioactive compounds and, thus, with high nutraceutical potential.

Plants used against obesity in Turkish folk medicine: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Obesity is one of the growing public health problems in Turkey, as well as all over the world, threatening people of almost all ages. Turkey has a large potential for research on this topic due to owning broad ethnomedicinal experience and the richest flora (34% endemic) of Europe and the Middle East. Herbs that they have utilized for centuries to treat and prevent obesity can provide useful options to overcome this issue.

AIM OF THE STUDY

This survey was carried out to disclose the inventory of plant taxa that the people of Turkey have been using for a few centuries in treating obesity without any side effects or complications, and to compare them with experimental studies in the literature.

MATERIALS AND METHODS

The research was achieved in two phases on the matter above by using electronic databases, such as Web of Science, ScienceDirect, Scopus, ProQuest, Medline, Cochrane Library, EBSCO, HighWire Press, PubMed and Google Scholar. Both results were shown in separate tables as well as the regional comparative analysis.

RESULTS

117 herbal taxa belonging to 45 families were identified among the selected 74 studies conducted in the seven regions of Turkey. However, only 49 (41.9%) of them were found to be subjected to worldwide in vitro and in vivo research conducted on anti-obesity activity. Quercetin (9.1%), gallic acid (6.1%) and ferulic acid and epigallocatechin gallate (4.5%) have been recorded as the most common active ingredients among the 66 active substances identified. Prunus avium (32.4%) and Rosmarinus officinalis (25.7%) were identified as the most common plants used in Turkey. Also, Portulaca oleracea and Brassica oleracea emerged as the most investigated taxa in the literature.

CONCLUSION

This is the first country-wide ethnomedical review conducted on obesity treatment with plants in Turkey. Evaluating the results of the experimental anti-obesity research conducted in the recent years in the literature, it was determined that forty-nine plants were verified. This clearly shows that these herbs have a high potential to be a pharmacological resource. Moreover, 68 (41.9%) taxa, which haven't been investigated yet, are likely to be a promising resource for national and international pharmacological researchers in terms of new natural medicine searches.

Ellagic Acid Affects Metabolic and Transcriptomic Profiles and Attenuates Features of Metabolic Syndrome in Adult Male Rats

Ellagic acid, a natural substance found in various fruits and nuts, was previously shown to exhibit beneficial effects towards metabolic syndrome. In this study, using a genetic rat model of metabolic syndrome, we aimed to further specify metabolic and transcriptomic responses to ellagic acid treatment. Adult male rats of the SHR-Zbtb16^Lx/k.o. strain were fed a high-fat diet accompanied by daily intragastric gavage of ellagic acid (50 mg/kg body weight; high-fat diet–ellagic acid (HFD-EA) rats) or vehicle only (high-fat diet–control (HFD-CTL) rats). Morphometric and metabolic parameters, along with transcriptomic profile of liver and brown and epididymal adipose tissues, were assessed. HFD-EA rats showed higher relative weight of brown adipose tissue (BAT) and decreased weight of epididymal adipose tissue, although no change in total body weight was observed. Glucose area under the curve, serum insulin, and cholesterol levels, as well as the level of oxidative stress, were significantly lower in HFD-EA rats. The most differentially expressed transcripts reflecting the shift induced by ellagic acid were detected in BAT, showing downregulation of BAT activation markers Dio2 and Nr4a1 and upregulation of insulin-sensitizing gene Pla2g2a. Ellagic acid may provide a useful nutritional supplement to ameliorate features of metabolic syndrome, possibly by suppressing oxidative stress and its effects on brown adipose tissue.

Preparation of Chitosan/Alginate-ellagic Acid Sustained-release Microspheres and their Inhibition of Preadipocyte Adipogenic Differentiation

OBJECTIVE

In this study, chitosan/alginate-ellagic acid sustained-release microspheres were prepared, and the effect of sustained-release microspheres on preadipocyte adipogenic differentiation was analyzed.

METHODS

Chitosan/alginate-ellagic acid microspheres were prepared and identified by scanning electron microscopy (SEM) and infrared spectroscopy (IR). The drug release rates were measured at pH 6.8, 7.0, 7.2, 7.4 to determine sustained release of ellagic acid from microspheres. The effects of 0.1, 1, 10 mg/L chitosan/alginate-ellagic acid microsphere on 3T3-F442A preadipocyte proliferation were determined by Methyl thiazolyl tetrazolium assay (MTT), and cell morphology was checked by hematoxylin/ eosin staining (HE staining). The effect of chitosan/alginate-ellagic acid microspheres on preadipocyte adipogenic differentiation was also determined by Oil red O staining, and lipogenesis was measured by isopropanol extraction. The molecular mechanism was investigated by detecting the mRNA expression of CCAAT/enhancer binding protein alpha (C/EBPα) and peroxisome proliferatorsactivated receptor gamma (PPARγ).

RESULTS

Chitosan/alginate-ellagic acid sustained-release microspheres were successfully prepared, and the inhibition of proliferation and adipogenic differentiation of preadipocytes was found to be dosedependent. The mechanism of differentiation inhibition was found to be closely related to the expression of transcription factor C/EBPα and PPARγ.

CONCLUSION

Chitosan/alginate can be used as a good material to prepare ellagic acid sustained-release microspheres, and these microspheres can be used for treating the obesity.

Pomegranate peel polyphenols inhibits inflammation in LPS-induced RAW264.7 macrophages via the suppression of TLR4/NF-κB pathway activation

BACKGROUNDS

Inflammatory response mediated by activated immune cells is a vital process in host defense system while responding to various stresses. Our previous studies have indicated that pomegranate peel polyphenols (PPPs) and their main components punicalagin (PC) and ellagic acid (EA) decreased pro-inflammatory cytokines and inflammatory mediators by regulating the mitogen-activated protein kinases (MAPKs) pathway, but whether these tested polyphenols play an important role in NF-κB signaling pathway, another crucial pathway of inflammation, remains unclear.

OBJECTIVE

In this study, we analyzed the anti-inflammatory effect of these polyphenols via TLR4-NF-κB pathway in lipopolysaccharide (LPS)-induced RAW264.7 macrophages.

METHODS

Different concentrations of PPPs, PC, and EA were pre-incubated with RAW264.7 macrophages and then stimulated with LPS (1 μg/mL), and the effects of reactive oxygen species and TLR4 were investigated. Moreover, NF-κB p65 nuclear translocation and phosphorylation, and degradation of IκB were measured by Western blot. Furthermore, the influence of pro-inflammatory cytokines was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Our data showed that PPPs, PC, and EA inhibited LPS-induced intracellular ROS production and suppressed the mRNA and protein expression levels of TLR4 in a dose-dependent manner. Moreover, the anti-inflammatory mechanism was involved in blocking LPS-induced phosphorylation, degradation of IκB, and nuclear translocation of p65. Additionally, PPPs and PC exhibited a stronger anti-inflammatory effect than that of EA.

CONCLUSION

The results indicated that PPPs possess potent anti-inflammatory effect, and PC was the main effective component in PPPs, which provided new insights into the utilization of PPPs to prevent inflammation-associated disorders.

The Structures and Bioactivities of Fatty Acid Synthase Inhibitors

Background:

Fatty Acid Synthase (FAS or FASN) is a vital enzyme which catalyzes the de novo synthesis of long chain fatty acids. A number of studies have recently been reported that FAS was combined targets for the discovery of anti-obesity and anti-cancer drugs. Great interest has been developed in finding novel FAS inhibitors, and result in more than 200 inhibitors being reported.

Methods:

The reported research literature about the FAS inhibitors was collected and analyzedsised through major databases including Web of Science, and PubMed. Then the chemical stractures, FAS inhibitory activities, and Structure-Activity Relationships (SAR) were summarized focused on all these reported FAS inhibitors.

Results:

The 248 FAS inhibitors, which were reported during the past 20 years, could be divided into thiolactone, butyrolactone and butyrolactam, polyphenols, alkaloids, terpenoids, and other structures, in view of their structure characteristics. And the SAR of high inhibitory structures of each type was proposed in this paper.

Conclusion:

A series of synthetic quinolinone derivatives show strongest inhibitory activity in the reported FAS inhibitors. Natural polyphenols, existing in food and herbs, show more adaptive in medicine exploration because of their safety and efficiency. Moreover, screening the FAS inhibitors from microorganism and marine natural products could be the hot research directions in the future.

Moringa oleifera Leaf Petroleum Ether Extract Inhibits Lipogenesis by Activating the AMPK Signaling Pathway

In recent years, obesity has become a key factor affecting human health. Moringa oleifera Lam. is a perennial tropical deciduous tree, which is widely used in human medicine due to its nutritional and unique medicinal value. It has a cholesterol-lowering effect, but its mechanism of action is unclear. In this study, we elucidated the inhibitory effect of M. oleifera leaf petroleum ether extract (MOPEE) on lipid accumulation by in vitro and in vivo experiments, and we described its mechanism of action. MOPEE suppressed adipogenesis in 3T3-L1 adipocytes in a dose-dependent manner and had no effect on cell viability at doses up to 400 μg/ml. Furthermore, MOPEE (400 μg/ml) significantly downregulated the expression of adipogenesis-associated proteins [peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding proteins α and β (C/EBPα and C/EBPβ), and fatty acid synthase (FAS)] and upregulated the expression of a lipolysis-associated protein [hormone-sensitive lipase (HSL)] in 3T3-L1 adipocytes. Additionally, MOPEE (400 μg/ml) significantly increased the degree of phosphorylation of AMP-activated protein kinase α (AMPKα) and acetyl-CoA carboxylase (ACC). An AMPK inhibitor reversed the MOPEE-induced activation of AMPKα and ACC in 3T3-L1 adipocytes. Animal experiments showed that, in high-fat diet (HFD) mice, MOPEE [0.5 g/kg body weight (BW)] effectively decreased BW; relative epididymal, perirenal, and mesenteric fat weight and fat tissue size; and hepatic fat accumulation. Furthermore, MOPEE markedly reduced the serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and aspartate aminotransferase (AST). Moreover, MOPEE significantly downregulated the expression of adipogenesis-associated proteins (PPARγ and FAS) and upregulated the expression of a lipolysis-associated protein [adipose triglyceride lipase (ATGL)] in HFD mice hepatic and epididymal fat tissue. Additionally, MOPEE markedly increased the degree of phosphorylation of AMPKα and ACC in HFD mice hepatic and epididymal fat tissue. Following ultrahigh-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS/MS) analysis, three phytocompounds (isoquercitrin, chrysin-7-glucoside, and quercitrin) were identified as compounds with relatively high levels in MOPEE. Among them, quercitrin showed excellent fat accumulation inhibitory activity, and the three compounds had synergistic effects in inhibiting adipogenesis. Taken together, MOPEE inhibits fat accumulation by inhibiting the adipogenesis and promoting the lipolysis, and this process is related to AMPK activation.

Patuletin induces apoptosis of human breast cancer SK-BR-3 cell line via inhibiting fatty acid synthase gene expression and activity

Fatty acid synthase (FASN) is a key enzyme involved in fatty acid biosynthesis and serves an important role in breast cancer development. The aim of the present study was to investigate the effects of patuletin on the gene expression and activity of FASN in the human breast cancer SK-BR-3 cell line, and the apoptotic effects of patuletin to breast cancer cells. Quantitative reverse transcription polymerase chain reaction, western blotting and intracellular FASN activity assays were used to evaluate FASN gene expression, protein expression and activity in patuletin-treated SK-BR-3 cells. MTT assays and flow cytometry were used to measure cell growth and cell apoptosis, respectively, following patuletin treatment. As a result, it was demonstrated that patuletin dose-dependently reduces FASN expression and intracellular activity in human breast cancer cells, and induces apoptosis in FASN over-expressing SK-BR-3 cells. Notably, apoptosis is associated with the reduction of intracellular FASN activity. The present study demonstrates that patuletin may be considered as a novel natural inhibitor of FASN, may induce anti-proliferative and pro-apoptotic effects in certain human breast cancer cells and may be useful for preventing and/or treating human breast cancer.

Inhibitory effects of garcinone E on fatty acid synthase

Fatty acid synthase (FAS) is highly expressed in human adipocytes and cancer cells and is considered as a dual therapeutic target for obesity and cancer treatment. Garcinone E is a natural xanthone and exists in the pericarp of Garcinia mangostana. In previous studies, xanthones were reported to be highly active inhibitors of FAS. In the present study, the detailed inhibitory mechanism of garcinone E on FAS was investigated. We found that garcinone E inhibited the activity of FAS in a concentration-dependent manner with a half-inhibitory concentration value of 3.3 μM. The inhibition kinetic results showed that the inhibition of FAS by garcinone E was competitive with respect to acetyl-CoA, mixed competitive and noncompetitive with respect to malonyl-CoA, and noncompetitive to NADPH. In addition, garcinone E showed irreversible inhibition on FAS, which was different from all other xanthones. Since FAS is believed to be a therapeutic target for obesity and cancer treatment, these findings suggest the clinical potential of garcinone E in the prevention and treatment of both obesity and cancer.

Garcinone E exhibits both fast-binding reversible and time-dependent irreversible inhibition on the activity of fatty acid synthase.

Epigallocatechin-3-gallate suppresses differentiation of adipocytes via regulating the phosphorylation of FOXO1 mediated by PI3K-AKT signaling in 3T3-L1 cells

Epigallocatechin-3-gallate (EGCG) is a pivotal effective component of green tea. It is known that EGCG has antioxidant activity, anti-angiogenesis, anti-tumor, cardiovascular protection and blood lipid regulation functions. Forkhead box-O1 (FOXO1) is one of the downstream signals of protein kinase B (AKT) and takes part in adipogenesis. The purpose of this study is to investigate the effects of EGCG on adipose differentiation and the likely mechanisms. 3T3-L1 cells were induced by DMI for 2, 4, 6 and 8 days, respectively. During induction, the cells were treated with EGCG (5 μM, 10 μM, 50 μM and 100 μM) or DMSO for the first 2 days. In addition, another batch of 3T3-L1cells were treated with SC-3036 (PI3K activator, 10 µM), or LY294002 (PI3K inhibitor, 10 µM) alone or combined with EGCG (100 μM) for the indicated times. Medium glucose concentration, lipid accumulation, the levels of TNF-α, resistin, adiponectin and leptin and the expression of FOXO1, phosphorylated-FOXO1 (P-FOXO1), PPARγ, fatty acid synthase (FAS) were detected, respectively. The present study demonstrated that EGCG inhibited glucose uptake, lipid accumulation and adipokine secretion in a concentration-dependent manner during adipogenesis, which suggests that EGCG inhibits adipocyte’s differentiation, maturation and functions. Moreover, EGCG also down-regulated the expression levels of PPARγ and P-FOXO1. Conversely, the PI3K activator reversed these changes caused by EGCG, suggesting that the inhibitory effects of EGCG may be mediated by PI3K-AKT-FOXO1 pathway to negatively regulate the expression of PPARγ. The findings will provide a solid foundation for EGCG to prevent and cure the obesity-associated diseases.

Antiobesity and antihyperglycaemic effects of Adiantum capillus-veneris extracts: in vitro and in vivo evaluations

CONTEXT

Adiantum capillus-veneris L. (Adiantaceae) hypocholesterolemic activity is therapeutically praised.

OBJECTIVES

Pharmacological modulation of pancreatic triacylglycerol lipase (PL) and α-amylase/α-glucosidase by A. capillus-veneris are evaluated.

MATERIALS AND METHODS

Using positive controls (acarbose, orlistat, guar gum, atorvastatin, glipizide and metformin) as appropriate, crude aqueous extracts (AEs) of A. capillus-veneris aerial parts were tested via a combination of in vitro enzymatic (0.24-100 mg/mL), acute in vivo carbohydrate tolerance tests (125, 250 or 500 mg/kg body weight [b.wt]) and chronic in vivo studies (500 mg/kg b.wt) in high cholesterol diet (HCD) fed Wistar rats.

RESULTS

Like acarbose, A. capillus-veneris as well as chlorogenic acid, with respective IC₅₀ values (mg/mL) of 0.8 ± 0.0 and 0.2 ± 0.0, were identified as in vitro potent dual inhibitors of α-amylase/α-glucosidase. Unlike guar gum, A. capillus-veneris had no glucose diffusion hindrance capacity. Equivalent to orlistat, A. capillus-veneris and its phytoconstituents inhibited PL in vitro with an ascending order of PL- IC₅₀ values (μg/mL): ferulic acid; 0.48 ± 0.06 < ellagic acid; 13.53 ± 1.83 < chlorogenic acid; 38.4 ± 2.8 < A. capillus-veneris; 1600 ± 100. Incomparable to acarbose or metformin and glipizide, A. capillus-veneris (125, 250 and 500 mg/kg b.wt) lacked antihyperglycaemic efficacies in acute starch- or glucose-evoked postprandial hyperglycaemia increments in normoglycaemic overnight fasting rats. Superior to atorvastatin; A. capillus-veneris exerted significant antiobesity (p < 0.001) with marked triacylglycerol-reducing capacities (p < 0.001) in comparison to rats fed with HCD for 10 weeks.

DISCUSSION AND CONCLUSION

A. capillus-veneris, modulating pancreatic digestive enzymes, may be advocated as a combinatorial diabesity prevention/phytotherapy agent.

Phenolic Compounds of Pomegranate Byproducts (Outer Skin, Mesocarp, Divider Membrane) and Their Antioxidant Activities

Pomegranate peel was separated into outer leathery skin (PS), mesocarp (PM), and divider membrane (PD), and its phenolic compounds were extracted as free (F), esterified (E), and insoluble-bound (B) forms for the first time. The total phenolic content followed the order PD > PM > PS. ABTS(•+), DPPH, and hydroxyl radical scavenging activities and metal chelation were evaluated. In addition, pomegranate peel extracts showed inhibitory effects against α-glucosidase activity, lipase activity, and cupric ion-induced LDL-cholesterol oxidation as well as peroxyl and hydroxyl radical-induced DNA scission. Seventy-nine phenolic compounds were identified using HPLC-DAD-ESI-MS(n) mainly in the form of insoluble-bound. Thirty compounds were identified for the first time. Gallic acid was the major phenolic compound in pomegranate peel, whereas kaempferol 3-O-glucoside was the major flavonoid. Moreover, ellagic acid and monogalloyl-hexoside were the major hydrolyzable tannins, whereas the dominant proanthocyanidin was procyanidin dimers. Proanthocyanidins were detected for the first time.

Effects of pomegranate peel polyphenols on lipid accumulation and cholesterol metabolic transformation in L-02 human hepatic cells via the PPARγ-ABCA1/CYP7A1 pathway

PPPs, PC and PEA in different concentrations were found to decrease the total cholesterol (TC) content and increase the total bile acid (TBA) content of a human hepatic cell model, and so possess a lipid-lowering effect.

In vitro steatosis hepatic cell model to compare the lipid-lowering effects of pomegranate peel polyphenols with several other plant polyphenols as well as its related cholesterol efflux mechanisms

This study was aimed to compare the relative activities of the purified pomegranate peels polyphenols (PPPs) with some other plant polyphenols including punicalagin, ellagic acid, gallic acid, phlorizin, and epigallocatechin gallate (EGCG) on the lipid metabolism regulation, and the cholesterol efflux mechanisms of PPPs and punicalagin were also investigated. In this paper, a convenient and accurate in vitro HL7702 steatosis hepatic cell model was applied to evaluate the lipid-lowering effects of the tested polyphenols. The results showed that PPPs possessed the strongest lipid-lowering effects. Prevention group (treated with polyphenols when establishing of steatosis model) was more effective than treatment group (treated with polyphenols after establishment of steatosis model). Punicalagin displayed the strongest lipid-lowering effects among all the tested components of pomegranate peel polyphenols. Moreover, PPPs and punicalagin (10, 20, 40 μg/mL) significantly increased the mRNA expression of LXRα (Liver X receptor alpha) and its target genes-ABCA1 (ATP-binding cassette transporter A1) in a dose-dependent manner in HL7702 steatosis hepatic cells. The high mRNA expression of LXRα and ABCA1, next to lovastatin, was observed in cells treated with 40 μg/mL of PPPs. These in vitro findings suggested that PPPs might have great potential in the clinic treatment of hyperlipemia.

2,4,5-trimethoxybenzaldehyde, a bitter principle in plants, suppresses adipogenesis through the regulation of ERK1

Because of the prevalence of obesity, there is particular interest in finding potential therapeutic targets. In a previous study, we demonstrated that 2,4,5-trimethoxybenzaldehyde (2,4,5-TMBA), a bitter principle in plants and a natural cyclooxygenase II (COX-2) inhibitor, suppressed the differentiation of preadipocyts into adipocytes at the concentration of 0.5 mM. In this current study, we aimed to investigate the stage during adipogenesis that is critically affected by 2,4,5-TMBA and the effects of 2,4,5-TMBA on the time-course expression of signaling molecules MAP kinase kinase (MAPKK, represented by MEK) and extracellular signal-regulated kinase (ERK), transcription factors CCAAT/enhancer binding protein (C/EBP)α, β, and δ and peroxisome proliferator-activated receptor (PPAR)γ, lipogenic enzymes acetyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), and lipid droplet-coating protein perilipin A. When preadipocytes were co-cultured with 2,4,5-TMBA (0.5 mM) specifically at post-induction days 0-2, 2-4, 4-6, or 6-8 only, relative lipid accumulation was decreased by 67.93, 34.65, 49.56, and 34.32%, respectively. A time-course study showed that treatment of 2,4,5-TMBA suppressed the phosphorylation of ERK1 at the initial stage of adipogenesis but upregulated the phosphorylation at the late stage, which is opposite to the conditions required for the differentiation process. The overall expression of C/EBPα, β, and δ, PPARγ2, ACC, FAS, and perilipin A in preadipocytes was downregulated by the treatment of 2,4,5-TMBA. Taken together, our findings suggest that 2,4,5-TMBA suppresses adipogenesis through the regulation of ERK1 phosphorylation. Although results from in vitro studies cannot be directly extrapolated into clinical effects, our study will help to elucidate the anti-adipogenic potential of 2,4,5-TMBA.

Apoptotic effect of genistein on human colon cancer cells via inhibiting the nuclear factor-kappa B (NF-κB) pathway

Genistein possesses a wide variety of biological activities, and it is best known for its ability to inhibit cancer progression. Its cancer-preventive effect has been attributed to various mechanisms, including the induction of cell cycle arrest and apoptosis as well as the antioxidant functions. Nuclear factor kappa-B (NF-κB) is a signaling pathway that controls transcriptional activation of genes important for the tight regulation of many cellular processes and is aberrantly expressed in many types of cancer. Inhibitors of NF-κB pathway have shown potential anti-tumor activities. However, it is not fully elucidated in colon cancer. In the present study, we demonstrated that genistein could induce apoptosis in human colon cancer LoVo and HT-29 cells through inhibiting NF-κB pathway, as well as downregulation of Bcl-2 and upregulation of Bax, thus providing basis for clinical application of genistein in colon cancer cases.