Purification and identification of adipogenesis inhibitory peptide from black soybean protein hydrolysate

Comprehensive review of plant-derived anti-hyperlipidemia peptides: Production, anti-hyperlipidemia mechanism, and structure-activity relationship study

Hyperlipidemia, an elevated level of cholesterol and/or triglycerides, has become a major public health problem worldwide. Although drugs intervention is effective in treating hyperlipidemia, most of them have adverse side effects. Peptides from natural plants with high anti-hyperlipidemic activity and a strong safety profile have emerged as promising candidates to prevent and ameliorate hyperlipidemia. This review summarizes the recent advances in plant-derived anti-hyperlipidemic peptides in terms of their sources, production, purification, identification, and activity evaluation. The focus is extended to their potential anti-hyperlipidemic mechanisms and structure-function relationships. Bioactive peptides derived from various plant sources, especially peptides containing hydrophobic and/or acidic amino acids, have shown remarkable effects in hyperlipidemic treatment. Their anti-hyperlipidemic effects are mediated by various mechanisms, including regulation of cholesterol metabolism and triglyceride metabolism, inhibition of inflammation-related metabolic syndrome, and modulation of the gut microbiota. Further evaluation of the stability, bioavailability, and clinical efficacy of these peptides is recommended.

Lemon basil seed-derived peptide: Hydrolysis, purification, and its role as a pancreatic lipase inhibitor that reduces adipogenesis by downregulating SREBP-1c and PPAR-γ in 3T3-L1 adipocytes

The purpose of this study is to assess the bioactive peptides derived from the defatted lemon basil seeds hydrolysate (DLSH) for their ability to inhibit pancreatic lipase, decrease intracellular lipid accumulation, and reduce adipogenesis. Response surface methodology (RSM) was employed to optimize trypsin hydrolysis conditions for maximizing lipase inhibitory activity (LI). A hydrolysis time of 387.06 min, a temperature of 49.03°C, and an enzyme concentration of 1.61% w/v, resulted in the highest LI with an IC50 of 368.07 μg/mL. The ultrafiltration of the protein hydrolysate revealed that the fraction below 0.65kDa exhibited the greatest LI potential. Further purification via RP-HPLC identified the Gly-Arg-Ser-Pro-Asp-Thr-His-Ser-Gly (GRSPDTHSG) peptide in the HPLC fraction F1 using mass spectrometry. The peptide was synthesized and demonstrated LI with an IC50 of 0.255 mM through a non-competitive mechanism, with a constant (Ki) of 0.61 mM. Docking studies revealed its binding site with the pancreatic lipase-colipase complex. Additionally, GRSPDTHSG inhibited lipid accumulation in 3T3-L1 cells in a dose-dependent manner without cytotoxic effects. Western blot analysis indicated downregulation of PPAR-γ and SREBP-1c levels under GRSPDTHSG treatment, while an increase in AMPK-α phosphorylation was observed, suggesting a role in regulating cellular lipid metabolism. Overall, GRSPDTHSG demonstrates potential in attenuating lipid absorption and adipogenesis, suggesting a prospective application in functional foods and nutraceuticals.

The Research Progress of Bioactive Peptides Derived from Traditional Natural Products in China

Traditional natural products in China have a long history and a vast pharmacological repertoire that has garnered significant attention due to their safety and efficacy in disease prevention and treatment. Among the bioactive components of traditional natural products in China, bioactive peptides (BPs) are specific protein fragments that have beneficial effects on human health. Despite many of the traditional natural products in China ingredients being rich in protein, BPs have not received sufficient attention as a critical factor influencing overall therapeutic efficacy. Therefore, the purpose of this review is to provide a comprehensive summary of the current methodologies for the preparation, isolation, and identification of BPs from traditional natural products in China and to classify the functions of discovered BPs. Insights from this review are expected to facilitate the development of targeted drugs and functional foods derived from traditional natural products in China in the future.

Production of Food-Derived Bioactive Peptides with Potential Application in the Management of Diabetes and Obesity: A Review

The prevalence of diabetes mellitus and obesity is increasing worldwide. Bioactive peptides are naturally present in foods or in food-derived proteins. Recent research has shown that these bioactive peptides have an array of possible health benefits in the management of diabetes and obesity. First, this review will summarize the top-down and bottom-up production methods of the bioactive peptides from different protein sources. Second, the digestibility, bioavailability, and metabolic fate of the bioactive peptides are discussed. Last, the present review will discuss and explore the mechanisms by which these bioactive peptides help against obesity and diabetes based on in vitro and in vivo studies. Although several clinical studies have demonstrated that bioactive peptides are beneficial in alleviating diabetes and obesity, more double-blind randomized controlled trials are needed in the future. This review has provided novel insights into the potential of food-derived bioactive peptides as functional foods or nutraceuticals to manage obesity and diabetes.

Hair Growth Promotion with Black Soybean Extracts: case series

Black soybean (BS) is widely thought to prevent or alleviate hair loss, which has been demonstrated by in vitro experiments. However, few clinical studies have directly assessed the effect of BS on hair growth. To assess the safety and efficacy of BS, we administered BS extract to 10 adult patients for 3 months without any other hair products and treatments. The number and diameter of hair lost from washing were examined every 4 weeks. In addition, the participants’ satisfaction with their hair condition was also measured using the VAS (1 to 10) before and after treatment. The mean number of lost hair was 140.7 (SD 59.4) at baseline and 38.8 (SD 54.4) after 12 weeks, and the diameter of lost hair was 72.4 µm (SD 11.9) at baseline and 80.4 µm (SD 8.8) after 12 weeks, which indicated a statistically significant improvement (p = 0.002, p = 0.022, paired t-test). The satisfaction score was significantly increased from 6.10 (SD 1.2) to 8.2 (SD 1.1) after 12 weeks. These results suggest that BS extract may promote hair growth and prevent hair loss.

Rhynchosia volubilis Promotes Cell Survival via cAMP-PKA/ERK-CREB Pathway

Rhynchosia volubilis, a small black bean, has been used as a traditional remedy to treat diseases and maintain health in East Asia, but its cellular effects and molecular mechanisms are not fully understood. The purpose of this study was to investigate the effect of ethanol extract from Rhynchosia volubilis (EERV) on cell survival and to elucidate the biochemical signaling pathways. Our results showed that EERV stimulated the cyclic AMP (cAMP) signal revealed by a fluorescent protein (FP)-based intensiometric sensor. Using a Förster resonance energy transfer (FRET)-based sensor, we further revealed that EERV could activate PKA and ERK signals, which are downstream effectors of cAMP. In addition, we reported that EERV could induce the phosphorylation of CREB, a key signal for cell survival. Thus, our results suggested that EERV protects against apoptosis by activating the cell survival pathway through the cAMP-PKA/ERK-CREB pathway.

Adipose and non-adipose perspectives of plant derived natural compounds for mitigation of obesity

ETHNOPHARMACOLOGICAL RELEVANCE

Phyto-preparations and phyto-compounds, by their natural origin, easy availability, cost-effectiveness, and fruitful traditional uses based on accumulated experiences, have been extensively explored to mitigate the global burden of obesity.

AIM OF THIS REVIEW

The review aimed to analyse and critically summarize the prospect of future anti-obesity drug leads from the extant array of phytochemicals for mitigation of obesity, using adipose related targets (adipocyte formation, lipid metabolism, and thermogenesis) and non-adipose targets (hepatic lipid metabolism, appetite, satiety, and pancreatic lipase activity). Phytochemicals as inhibitors of adipocyte differentiation, modulators of lipid metabolism, and thermogenic activators of adipocytes are specifically discussed with their non-adipose anti-obesogenic targets.

MATERIALS AND METHODS

PubMed, Google Scholar, Scopus, and SciFinder were accessed to collect data on traditional medicinal plants, compounds derived from plants, their reported anti-obesity mechanisms, and therapeutic targets. The taxonomically accepted name of each plant in this review has been vetted from "The Plant List" (www.theplantlist.org) or MPNS (http://mpns.kew.org).

RESULTS

Available knowledge of a large number of phytochemicals, across a range of adipose and non-adipose targets, has been critically analysed and delineated by graphical and tabular depictions, towards mitigation of obesity. Neuro-endocrinal modulation in non-adipose targets brought into sharp dual focus, both non-adipose and adipose targets as the future of anti-obesity research. Numerous phytochemicals (Berberine, Xanthohumol, Ursolic acid, Guggulsterone, Tannic acid, etc.) have been found to be effectively reducing weight through lowered adipocyte formation, increased lipolysis, decreased lipogenesis, and enhanced thermogenesis. They have been affirmed as potential anti-obesity drugs of future because of their effectiveness yet having no threat to adipose or systemic insulin sensitivity.

CONCLUSION

Due to high molecular diversity and a greater ratio of benefit to risk, plant derived compounds hold high therapeutic potential to tackle obesity and associated risks. This review has been able to generate fresh perspectives on the anti-diabetic/anti-hyperglycemic/anti-obesity effect of phytochemicals. It has also brought into the focus that many phytochemicals demonstrating in vitro anti-obesogenic effects are yet to undergo in vivo investigation which could lead to potential phyto-molecules for dedicated anti-obesity action.

Novel Zn-Binding Peptide Isolated from Soy Protein Hydrolysates: Purification, Structure, and Digestion

In this study, a novel Zn-binding peptide, Lys-Tyr-Lys-Arg-Gln-Arg-Trp (KYKRQRW), was purified and identified from soy protein isolate hydrolysates (SPIHs). The Zn-binding peptide exhibited improved Zn-binding capacity (83.21 ± 2.65%) than SPIH solutions. CD, NMR, and Fourier transform infrared spectroscopy were used to confirm the complexation between Zn and the peptide. The results showed that the Zn-binding peptide formed a folding structure with part of the β-sheet (29.3-13.4%) turning into random coils (41.7-57.6%) during complexation. It was further proved that the binding sites were located at the oxygen atoms on the carboxyl group of the Trp side chain and nitrogen atoms on the amino group of the Lys side chain. Moreover, the Zn-peptide complex exhibited increased solubility than ZnSO₄ during simulated gastrointestinal digestion. This study highlighted that the novel soy peptide possessed a strong zinc chelate rate and had a positive effect on the gastrointestinal stability of Zn which could be utilized as a functional ingredient in future.

Functional properties and adipogenesis inhibitory activity of protein hydrolysates from quinoa (Chenopodium quinoa Willd.)

The functional properties and adipogenesis inhibitory activity of quinoa protein hydrolysates, prepared using papain, pepsin, and pancreatin for 0, 30, 60, 90, and 120 min, were studied. For these three kinds of proteases, the solubility of the hydrolysates significantly increased with the increasing DH in pH range of 3-8, while the EAI and ESI of these hydrolysates significantly decreased during hydrolysis. The anti-inflammatory activity of these protein hydrolysates was measured. All of these protein hydrolysates showed high anti-inflammatory activity. However, there was no significant difference in anti-inflammatory activity between protein hydrolysates and total protein from quinoa. These protein hydrolysates also inhibited lipid accumulation during differentiation within the range of concentrations of 0-1,600 μg/ml, which exerted no cytotoxicity toward 3T3-L1 cells. The protein hydrolysates from quinoa prepared using pepsin for 120 min (PEP-120) had the highest activity with an IC50 value of 786.58 μg/ml. Moreover, LC-MS/MS analysis of PEP-120 showed that five main bioactive peptides, which have been demonstrated to have ACE inhibitor, antioxidant, and antithrombotic activities, were present in PEP-120. In addition, gene expression and Western blot analysis revealed that PEP-120 suppressed the 3T3-L1 cell differentiation through the peroxisome proliferator-activated receptor γ (PPARγ) pathway.

Recent update on methodologies for extraction and analysis of soybean seed proteins

Soybean is one of the best sources of plant protein. Development of improved soybean cultivars through classical breeding and new biotech approaches is important to meet the growing global demand for soybeans. There is a critical need to investigate changes in protein content and profiles to ensure the safety and nutritional quality of new soybean varieties and their food products. A proteomics study begins with an optimal combination of extraction, separation and detection approaches. This review attempts to provide a summary of current updates in the methodologies used for extraction, separation and detection of protein from soybean, the basic foundations for good proteomic research. This information can be effectively used to investigate modifications in protein content and profiles in new varieties of soybeans and other crops. © 2018 Society of Chemical Industry.

Soybean Bioactive Peptides and Their Functional Properties

Soy consumption has been associated with many potential health benefits in reducing chronic diseases such as obesity, cardiovascular disease, insulin-resistance/type II diabetes, certain type of cancers, and immune disorders. These physiological functions have been attributed to soy proteins either as intact soy protein or more commonly as functional or bioactive peptides derived from soybean processing. These findings have led to the approval of a health claim in the USA regarding the ability of soy proteins in reducing the risk for coronary heart disease and the acceptance of a health claim in Canada that soy protein can help lower cholesterol levels. Using different approaches, many soy bioactive peptides that have a variety of physiological functions such as hypolipidemic, anti-hypertensive, and anti-cancer properties, and anti-inflammatory, antioxidant, and immunomodulatory effects have been identified. Some soy peptides like lunasin and soymorphins possess more than one of these properties and play a role in the prevention of multiple chronic diseases. Overall, progress has been made in understanding the functional and bioactive components of soy. However, more studies are required to further identify their target organs, and elucidate their biological mechanisms of action in order to be potentially used as functional foods or even therapeutics for the prevention or treatment of chronic diseases.

A standardized extract of Rhynchosia volubilis Lour. exerts a protective effect on benzalkonium chloride-induced mouse dry eye model

ETHNOPHARMACOLOGICAL RELEVANCE

In contrast to other leguminous plants generally used as food, Rhynchosia volubilis Loureiro, a small soybean with a black seed coat, has been used as a traditional oriental remedy for various human diseases in Eastern Asia. In this study, we demonstrated the protective effect of R. volubilis against dry eye disease.

AIM OF THE STUDY

We aimed to investigate whether a standardized ethanol extract of R. volubilis (EERV) can protect the cornea in a benzalkonium chloride (BAC)-induced mouse dry eye model.

MATERIALS AND METHODS

Experimental dry eye was induced by the instillation of 0.2% BAC on mouse cornea. A standardized ethanol extract of R. volubilis (EERV) was orally administered following BAC treatment. The positive control group was treated with commercial eye drops. Fluorescein staining, tear break-up time (BUT), and hematoxylin and eosin staining were evaluated on the ocular surface. Squamous metaplasia and apoptosis in the corneal epithelial layer were detected by immunostaining. Furthermore, the protein expression of cytochrome c, Bcl-2, and Bax was determined.

RESULTS

EERV treatment significantly improved fluorescein scoring, BUT, and smoothness in the cornea compared to the vehicle group. In addition, EERV inhibited squamous metaplasia and apoptosis in the cornea. The expression of cytochrome c and Bax was upregulated, while that of Bcl-2 was downregulated in the vehicle group compared with that in the control group. However, EERV treatment inhibited the expression of cytochrome c and Bax, while that of Bcl-2 was improved.

CONCLUSION

Standardized EERV could be a beneficial candidate for the treatment of dry eye disease.

Enzymatic hydrolysate from velvet antler suppresses adipogenesis in 3T3-L1 cells and attenuates obesity in high-fat diet-fed mice

The purpose of the current study was to investigate the potential anti-obesity activity of an enzymatic hydrolysate of velvet antler in inhibiting adipogenesis in 3T3-L1 cells and in high-fat diet (HFD)-fed obese mice. The enzymatic hydrolysate was prepared using the commercial food grade protease, Protamex. The velvet antler Protamex hydrolysate (VAPH) indicated profound inhibitory effects on adipogenesis dose-dependently by decreasing the accumulation of triglycerides and down-regulating expression levels of adipogenesis-related proteins C/EBPα, SREBP-1, and PPARγ. In a mouse model of HFD-induced obesity, oral administration of VAPH (100 and 300 mg/kg for 13 weeks) significantly reduced the body weight gain that had resulted from the HFD. VAPH treatment also lowered the serum glucose and triglyceride levels, while increasing the HDL-C level. Furthermore, the treatment greatly reduced hepatic lipid droplet accumulation as well as the size of adipocytes. Current findings demonstrate that VAPH has profound anti-obesity effects and could be an effective candidate for preventing obesity and obesity-related chronic diseases.

Biologically active peptides: Processes for their generation, purification and identification and applications as natural additives in the food and pharmaceutical industries

Recent technological advances have created great interest in the use of biologically active peptides. Bioactive peptides can be defined as specific portions of proteins with 2 to 20 amino acids that have desirable biological activities, including antioxidant, anti-hypertensive, antithrombotic, anti-adipogenic, antimicrobial and anti-inflammatory effects. Specific characteristics, including low toxicity and high specificity, make these molecules of particular interest to the food and pharmaceutical industries. This review focuses on the production of bioactive peptides, with special emphasis on fermentation and enzymatic hydrolysis. The combination of different technologies and the use of auxiliary processes are also addressed. A survey of isolation, purification and peptide characterization methods was conducted to identify the major techniques used to determine the structures of bioactive peptides. Finally, the antioxidant, antimicrobial, anti-hypertensive, anti-adipogenic activities and probiotic-bacterial growth-promoting aspects of various peptides are discussed.

Functional significance of bioactive peptides derived from soybean

Biologically active peptides play an important role in metabolic regulation and modulation. Several studies have shown that during gastrointestinal digestion, food processing and microbial proteolysis of various animals and plant proteins, small peptides can be released which possess biofunctional properties. These peptides are to prove potential health-enhancing nutraceutical for food and pharmaceutical applications. The beneficial health effects of bioactive peptides may be several like antihypertensive, antioxidative, antiobesity, immunomodulatory, antidiabetic, hypocholesterolemic and anticancer. Soybeans, one of the most abundant plant sources of dietary protein, contain 36-56% of protein. Recent studies showed that soy milk, an aqueous extract of soybean, and its fermented product have great biological properties and are a good source of bioactive peptides. This review focuses on bioactive peptides derived from soybean; we illustrate their production and biofunctional attributes.

Obesity-related metabolomic analysis of human subjects in black soybean peptide intervention study by ultraperformance liquid chromatography and quadrupole-time-of-flight mass spectrometry

The present study aimed to identify key metabolites related to weight reduction in humans by studying the metabolic profiles of sera obtained from 34 participants who underwent dietary intervention with black soybean peptides (BSP) for 12 weeks. This research is a sequel to our previous work in which the effects of BSP on BMI and blood composition of lipid were investigated. Sera of the study were subjected to ultra performance liquid chromatography and quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS), and the data were analyzed using partial least-squares discriminate analysis (PLS-DA) score plots. Body mass index and percent body fat of the test group were reduced. Levels of betaine, benzoic acid, pyroglutamic acid, pipecolic acid, N-phenylacetamide, uric acid, l-aspartyl-l-phenylalanine, and lysophosphatidyl cholines (lysoPCs) (C18:1, C18:2, C20:1, and C20:4) showed significant increases. Levels of l-proline, valine, l-leucine/isoleucine, hypoxanthine, glutamine, l-methionine, phenylpyruvic acid, several carnitine derivatives, and lysoPCs (C14:0, PC16:0, C15:0, C16:0, C17:1, C18:0, and C22:0) were significantly decreased. In particular, lysoPC 16:0 with a VIP value of 12.02 is esteemed to be the most important metabolite for evaluating the differences between the 2 serum samples. Our result confirmed weight-lowering effects of BSP, accompanied by favorable changes in metabolites in the subjects' blood. Therefore, this research enables us to better understand obesity and increases the predictability of the obesity-related risk by studying metabolites present in the blood.

Optimization of the preparation of fish protein anti-obesity hydrolysates using response surface methodology

The enzymatic condition for producing the anti-obesity hydrolysates from fish water-soluble protein was optimized with the aid of response surface methodology, which also derived a statistical model for experimental validation. Compared with neutral protease, papain and protamex, the porcine pancreas lipase inhibitory rate of hydrolysates from fish water-soluble protein was higher with alkaline protease. Results showed that the model terms were significant, the terms of lack of fit were not significant, and the optimal conditions for the hydrolysis by alkaline protease were initial pH 11, temperature 39 °C, enzyme dosage 122 U/mL and 10 h of hydrolysis time. Under these conditions, the porcine pancreas lipase and the α-amylase inhibitory rate could reach 53.04% ± 1.32% and 20.03 ± 0.89%, while predicted value were 54.63% ± 1.75%, 21.22% ± 0.70%, respectively. In addition, Lineweaver-Burk plots showed noncompetitive inhibition. The K_i value calculated was 84.13 mg/mL. These results demonstrated that fish water-soluble protein could be used for obtaining anti-obesity hydrolysates.

Weight reduction effects of a black soy peptide supplement in overweight and obese subjects: double blind, randomized, controlled study

The present study determined the effect of black soy peptide supplementation on body weight and body fat in overweight/obese subjects. In a double-blind controlled trial, participants (n = 80) were randomized to either soy peptide supplementation (the test group) or to a placebo (the placebo group). Sixty-four people completed the study, and anthropometric parameters, serum inflammatory markers, and leptin and lipid profiles were measured. After 6 weeks, the test group (n = 35) had significant reductions in body weight (p = 0.003) and body mass index (BMI) (p = 0.004), body fat mass (p = 0.038). After 12 weeks, they also had significant reductions in body weight (p < 0.001), BMI (p < 0.001), body fat percentage (p = 0.002), and body fat mass (p = 0.001). However, these significances were not observed in the placebo group (n = 29). In addition, net changes in body weight and body fat mass in the test group were significantly bigger than those in the placebo group after 12 weeks. Leptin levels were significantly reduced in the test groups (p = 0.047), but were not observed in the placebo group (p = 0.323). Interestingly, the subjects with weight reductions ≥1kg in the test group had greater reductions in circulating leptin levels (p = 0.002). Additionally, fasting insulin levels were significantly reduced in the test groups. The conclusion is that black soy peptide supplementation may be beneficial for body weight control in overweight/obese subjects.

Effect of germinated soybean protein hydrolysates on adipogenesis and adipolysis in 3T3-L1 cells

Germination of soybeans increases the bioavailability of some nutrients. An evaluation was done to determine if germination increased the anti-adipogenic and lipolytic effects of soybean. Soybeans were germinated for 0 to 6 days and protein concentrates extracted from beans germinated at each period. Soy protein concentrates can retain notable amounts of phytochemicals with anti-adipogenic activity. For this reason, it was evaluated the effect of protein hydrolysates with and without phytochemicals in the adipocyte-like cells after 3T3-L1 (murine fibroblasts) cell line differentiation. Cell viability decreased with exposure to the germinated soybean protein hydrolysates during the differentiation stage, but not during the fibroblast or mature adipocyte stages. Adipogenesis and triglycerides accumulation were strongly inhibited by the hydrolysate from soybeans germinated for 2 days (with ethanol-soluble phytochemicals), when compared to ungerminated soybean. Adipolysis increased with exposure to hydrolysates from beans germinated for 2 days (with phytochemicals) and 5 days (without phytochemicals). Germinated soy protein hydrolysates had an effect on inhibition of lipid storage in adypocites and increasing lipolysis, which was improved by changes of the protein and increased phytochemical content due to germination.

Human cancer cell proliferation inhibition by a pentapeptide isolated and characterized from rice bran

Food-derived bioactive peptides promote functional activity against diseases and present as nutraceutical agents. The purpose of our research was to isolate and fully characterize peptide(s) derived from rice bran having anti-cancer properties. Gastrointestinal juices resistant peptide fractions were initially generated from heat stabilized de-fatted rice bran from which <5 kDa fraction was shown to inhibit proliferation of cancer cells. Based on these published findings the <5 kDa peptide fraction was selected for further characterization to obtain single pure peptide(s) with enhanced anti-cancer properties. Purification and characterization from the fraction was done employing chromatography and mass spectrometric techniques. Cancer cell viability was measured using a cell titer assay that uses a tetrazolium dye [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium, inner salt; (MTS)] and the electron coupling reagent, phenazine methosulfate. Ion-exchange chromatography elutes that showed anti-cancer properties were further purified to liberate pure peptide. The pure peptide at 600-700 microg/mL dose caused 84% inhibition to colon cancer cells (Caco-2, HCT-116) growth, 80% to breast cancer cells (MCF-7, MDA-MB-231) growth and 84% to liver cancer cells (HepG-2) growth. Mass spectrometry analysis and de novo sequencing revealed the sequence of Glu-Gln-Arg-Pro-Arg for the peptide with a molecular mass of 685.378 Da. A novel pentapeptide was isolated from rice bran to possess cancer growth inhibitory properties on colon, breast, lung and liver cancer cells. This peptide could serve as a nutraceutical agent against cancer.