Anti-Obesity Effect of DKB-117 through the Inhibition of Pancreatic Lipase and α-Amylase Activity

Anti-obesity and anti-diabetic bioactive peptides: A comprehensive review of their sources, properties, and techno-functional challenges

The scourge of obesity arising from obesogens and poor dieting still ravages our planet as half of the global population may be overweight and obese by 2035. This metabolic disorder is intertwined with type 2 diabetes (T2D), both of which warrant alternative therapeutic options other than clinically approved drugs like orlistat with their tendency of abuse and side effects. In this review, we comprehensively describe the global obesity problem and its connection to T2D. Obesity, overconsumption of fats, the mechanism of fat digestion, obesogenic gut microbiota, inhibition of fat digestion, and natural anti-obesity compounds are discussed. Similar discussions are made for diabetes with regard to glucose regulation, the diabetic gut microbiota, and insulinotropic compounds. The sources and production of anti-obesity bioactive peptides (AOBPs) and anti-diabetic bioactive peptides (ADBPs) are also described while explaining their structure-function relationships, gastrointestinal behaviors, and action mechanisms. Finally, the techno-functional applications of AOBPs and ADBPs are highlighted.

The Antiobesity Effects and Potential Mechanisms of Theaflavins

Theaflavins are the characteristic polyphenols in black tea which can be enzymatically synthesized. In this review, the effects and molecular mechanisms of theaflavins on obesity and its comorbidities, including dyslipidemia, insulin resistance, hepatic steatosis, and atherosclerosis, were summarized. Theaflavins ameliorate obesity potentially via reducing food intake, inhibiting pancreatic lipase to reduce lipid absorption, activating the adenosine monophosphate-activated protein kinase (AMPK), and regulating the gut microbiota. As to the comorbidities, theaflavins ameliorate hypercholesterolemia by inhibiting micelle formation to reduce cholesterol absorption. Theaflavins improve insulin sensitivity by increasing the signaling of protein kinase B, eliminating glucose toxicity, and inhibiting inflammation. Theaflavins ameliorate hepatic steatosis via activating AMPK. Theaflavins reduce atherosclerosis by upregulating nuclear factor erythropoietin-2-related factor 2 signaling and inhibiting plasminogen activator inhibitor 1. In randomized controlled trails, black tea extracts containing theaflavins reduced body weight in overweight people and improved glucose tolerance in healthy adults. The amelioration on the hyperlipidemia and the prevention of coronary artery disease by black tea extracts were supported by meta-analysis.

Lavandula angustifolia mill. (Lamiaceae) ethanol extract and its main constituents as promising agents for the treatment of metabolic disorders: chemical profile, in vitro biological studies, and molecular docking

Lavandula angustifolia Mill. (lavender) is one of the most used medicinal plants. Herein, we chemically characterised and investigated the antioxidant properties and the capability to inhibit key enzymes for the treatment of type 2 diabetes (TD2) and obesity such as pancreatic lipase, α-glucosidase, and α-amylase of the ethanolic extract of two lavender samples (La1 and La2) from southern Italy. Both extracts significantly inhibited α-glucosidase, while La1 inhibited α-amylase and lipase more effectively than La2. To investigate whether these properties could be due to a direct interaction of the main constituents of the extracts with the targeted enzymes, molecular docking studies have been performed. As a result, the selected compounds were able to interact with the key residues of the binding site of the three proteins, thus supporting biological data. Current findings indicate the new potential of lavender ethanolic extract for the development of novel agents for T2D and obesity.

A Rational Combination of Cyclocarya paliurus Triterpene Acid Complex (TAC) and Se-Methylselenocysteine (MSC) Improves Glucose and Lipid Metabolism via the PI3K/Akt/GSK3β Pathway

Cyclocarya paliurus (CP) contains triterpene acids that can improve glucose and lipid metabolism disorders. However, controlling the composition and content of these active ingredients in CP extracts is challenging. The main active components in CP triterpene acids, including ursolic acid (UA), oleanolic acid (OA), and betulinic acid (BA), exhibit antihyperglycemic and antihypertensive effects. The response surface methodology was utilized to design and optimize the ratio of UA, OA, and BA based on the inhibition rate of pancrelipase and α-amylase. The proportional mixture of UA, OA, and BA resulted in the formation of a complex known as Cyclocarya paliurus triterpenoid acid (TAC). Se-methylselenocysteine (MSC), a compound with various physiological functions such as antioxidant properties and tumor inhibition, has been used in combination with TAC to form the TAC/MSC complex. Our data demonstrate that TAC/MSC improved palmitic acid (PA)-induced insulin resistance in HepG2 cells through activating the phosphoinositide 3-kinase (PI3K) /protein kinase B (AKT)/glycogen synthase kinase 3 beta (GSK3β) pathway. Moreover, TAC/MSC effectively improved hyperglycemia, glucose intolerance, insulin resistance, and lipid metabolism disorder in mice with type 2 diabetes mellitus (T2DM), attenuated hepatic steatosis, and reduced oxidative stress to alleviate T2DM characteristics.

Hydroxylated polymethoxyflavones reduce the activity of pancreatic lipase, inhibit adipogenesis and enhance lipolysis in 3T3-L1 mouse embryonic fibroblast cells

Hydroxylated polymethoxyflavones (HPMFs) have been shown to possess various anti-disease effects, including against obesity. This study investigates the anti-obesity effects of HPMFs in further detail, aiming to gain understanding of their mechanism of action in this context. The current study demonstrates that two HPMFs; 3'-hydroxy-5,7,4',5'-tetramethoxyflavone (3'OH-TetMF) and 4'-hydroxy-5,7,3',5'-tetramethoxyflavone (4'OH-TetMF) possess anti-obesity effects. They both significantly reduced pancreatic lipase activity in a competitive manner as demonstrated by molecular docking and kinetic studies. In cell studies, it was revealed that both of the HPMFs suppress differentiation of 3T3-L1 mouse embryonic fibroblast cells during the early stages of adipogenesis. They also reduced expression of key adipogenic and lipogenic marker genes, namely peroxisome proliferator-activated receptor-gamma (PPAR-γ), CCAAT/enhancer-binding protein α and β (C/EBP α and β), adipocyte binding protein 2 (aP2), fatty acid synthase (FASN), and sterol regulatory element-binding protein 1 (SREBF 1). They also enhanced the expression of cell cycle genes, i.e., cyclin D1 (CCND1) and C-Myc, and reduced cyclin A2 expression. When further investigated, it was also observed that these HPMFs accelerate lipid breakdown (lipolysis) and enhance lipolytic gene expression. Moreover, they also reduced the secretion of proteins (adipokines), including pro-inflammatory cytokines, from mature adipocytes. Taken together, this study concludes that these HPMFs have anti-obesity effects, which are worthy of further investigation.

Ultrasonic-assisted enzymatic improvement of polyphenol content, antioxidant potential, and in vitro inhibitory effect on digestive enzymes of Miang extracts

The aims of this research were to optimize the ultrasonic-assisted enzymatic extraction of polyphenols under Miang and tannase treatment conditions for the improvement of antioxidant activity of Miang extracts via response surface methodology. Miang extracts treated with and without tannase were investigated for their inhibitory effects on digestive enzymes. The optimal conditions for ultrasonic-assisted enzymatic extraction of the highest total polyphenol (TP) (136.91 mg GAE/g dw) and total flavonoid (TF) (5.38 mg QE/g dw) contents were as follows: 1 U/g cellulase, 1 U/g xylanase, 1 U/g pectinase, temperature (74 °C), and time (45 min). The antioxidant activity of this extract was enhanced by the addition of tannase obtained from Sporidiobolus ruineniae A45.2 undergoing ultrasonic treatment and under optimal conditions (360 mU/g dw, 51 °C for 25 min). The ultrasonic-assisted enzymatic extraction selectively promoted the extraction of gallated catechins from Miang. Tannase treatment improved the ABTS and DPPH radical scavenging activities of untreated Miang extracts by 1.3 times. The treated Miang extracts possessed higher IC₅₀ values for porcine pancreatic α-amylase inhibitory activity than those that were untreated. However, it expressed approximately 3 times lower IC₅₀ values for porcine pancreatic lipase (PPL) inhibitory activity indicating a marked improvement in inhibitory activity. The molecular docking results support the contention that epigallocatechin, epicatechin, and catechin obtained via the biotransformation of the Miang extracts played a crucial role in the inhibitory activity of PPL. Overall, the tannase treated Miang extract could serve as a functional food and beneficial ingredient in medicinal products developed for obesity prevention.

Interaction of Jania rubens Polyphenolic Extract as an Antidiabetic Agent with α-Amylase, Lipase, and Trypsin: In Vitro Evaluations and In Silico Studies

Jania rubens red seaweed has various bioactive compounds that can be used for several medicinal and pharmaceutical applications. In this study, we investigate the antidiabetic, anti-inflammatory, and antioxidant competency of Jania rubens polyphenolic extract (JRPE) by assessing their interactions with α-amylase, lipase, and trypsin enzymes. HPLC analysis revealed the dominance of twelve polyphenolic compounds. We performed computational analysis using α-amylase, lipase, and trypsin as target proteins for the polyphenols to explore their activities based on their predicted modes of binding sites following molecular modeling analysis. The molecular docking analysis demonstrated a good affinity score with a noticeable affinity to polyphenolic compositions of Jania rubens. The compounds with the highest affinity score for α-amylase (PDB: 4W93) were kaempferol, quercetin, and chlorogenic acid, with −8.4, −8.8 and −8 kcal/mol, respectively. Similarly, lipase (PDB: 1LPB) demonstrated high docking scores of −7.1, −7.4, and −7.2 kcal/mol for kaempferol, quercetin, and chlorogenic acid, respectively. Furthermore, for trypsin (PDB: 4DOQ) results, kaempferol, quercetin, and chlorogenic acid docking scores were −7.2, −7.2, and −7.1 kcal/mol, respectively. The docking findings were verified using in vitro evaluations, manifesting comparable results. Overall, these findings enlighten that the JRPE has antidiabetic, anti-inflammatory, and antioxidant properties using different diabetics’ enzymes that could be further studied using in vivo investigations for diabetes treatment.

Effects of Plant-Derived Glycerol Monolaurate (GML) Additive on the Antioxidant Capacity, Anti-Inflammatory Ability, Muscle Nutritional Value, and Intestinal Flora of Hybrid Grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂)

In a context where the search for plant-derived additives is a hot topic, glycerol monolaurate (GML) was chosen as our subject to study its effect on grouper (Epinephelus fuscoguttatus♀ × Epinephelus lanceolatus♂). Seven gradient levels of GML (0, 600, 1200, 1800, 2400, 3000, and 3600 mg/kg) were used for the experiment. Based on our experiments, 1800 mg/kg GML significantly increased the final body weight (FBW) and weight gain rate (WGR). GML increased the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and decreased malondialdehyde (MDA). Adding 1800 mg/kg GML also significantly increased the levels of lauric acid (C12:0) (LA), n-3 polyunsaturated fatty acids (PFA), and the n-6 PFA-to-n-3/n-6 ratio, while significantly decreasing the levels of saturated fatty acids (SFA). Dietary supplementation with GML significantly inhibited the expression of pro-inflammatory factors and reduced the occurrence of inflammation. GML improved intestinal flora and the abundance of beneficial bacteria (Bacillus, Psychrobacter, Acinetobacter, Acinetobacter, Stenotrophomonas, and Glutamicibacter). It provides a theoretical basis for the application of GML in aquafeed and greatly enhances the possibility of using GML in aquafeed. Based on the above experimental results, the optimum level of GML in grouper feed is 1800 mg/kg.

Antiobesity Potential of Bioactive Constituents from Dichloromethane Extract of Psoralea corylifolia L. Seeds

Purpose

Effectively controlling the accumulation of adipose tissue can be a therapeutic strategy for treating obesity, which is a global problem. The present study was designed for comparative assessment of in vitro antiobesity activities of the Psoralea corylifolia-dichloromethane seed extract (DCME) and the isolated phytochemicals, bakuchiol, isopsoralen, and psoralen, through antiadipogenesis and pancreatic lipase (PL) inhibition assays. Material and Methods. In vitro pancreatic lipase activity was determined spectrophotometrically by measuring the hydrolysis of p-nitrophenyl butyrate (p-NPB) to p-nitrophenol at 405 nm, and adipogenesis was assayed in 3 T3-L1 adipocytes (by using Oil Red O staining) using P. corylifolia-dichloromethane seed extract (DCME) and individual compounds, isolated from the extract.

Result

Antilipase as well as antiadipogenesis activity was displayed by both the DCME and the compounds. Maximum antilipase property was recorded in DCME (26.02 ± .041%) at 100 μg/ml, while, among the isolated compounds, bakuchiol exhibited a higher activity (24.2 ± 0.037%) at 100 μg/ml concentration, compared to other isolates. DCME was found to exhibit antiadipogenesis property, 75 ± 0.003% lipid accumulation, compared to the control at 100 μg/ml dose. Bakuchiol, isopsoralen, and psoralen inhibited the lipid accumulation in 3T3-L1 preadipocytes, 78.06 ± 0.002%, 80.91 ± 0.004%, and 80.91 ± 0.001%, respectively, lipid accumulation in comparison to control at 25 μM dose.

Conclusion

The present study highlights the antiobesity potential of P. corylifolia and its active constituents. Thus, it can be concluded that P. corylifolia has the potential to treat obesity and related diseases; however, further research on dose standardization and clinical trials are required.

Honeysuckle Berry (Lonicera caerulea L.) Inhibits Lipase Activity and Modulates the Gut Microbiota in High-Fat Diet-Fed Mice

Honeysuckle berry (HB, Lonicera caerulea L.) is an oriental herbal medicine reported to have beneficial effects on metabolic disorders, such as obesity and non-alcoholic fatty liver disease. The fruit part of HB is rich in anthocyanin, a type of polyphenol. Most studies credit the antioxidant and anti-inflammatory properties of HB as the mechanisms of its effectiveness. This study investigated the inhibitory effects of HB on lipase using an in vitro assay and the modulatory effect of HB on gut microbiota in high-fat diet (HFD)-fed mice. HB inhibited pancreatic lipase activity with IC50 values of approximately 0.47 mg/mL. The fecal triglyceride (TG) levels were higher from the HFD of the HB-fed mice than they were for the control mice. Moreover, the fecal microbiota from the HFD of the HB-fed mice had relatively lower Firmicutes and higher Bacteroidetes than that from the HFD-only mice. These results suggest that HB modulates gut microbiota composition, which may contribute to body fat reduction. Hence, HB could present a useful agent for treating metabolic diseases through lower TG uptake and the regulation of gut microflora.

Optimization of Pancreatic Lipase Inhibition in Fermented Beverages Brewed from Katuk Leaves Using RSM

The inhibition of pancreatic lipase and the associated reduction of lipid absorption has become the most appropriate approach for treating obesity. Meanwhile, katuk (Sauropus androgynus) leaves are rich in polyphenols that act as natural bioactive compounds and are also responsible for the potential effect on metabolic diseases, including inhibition of pancreatic lipase activity. Naturally occurring polyphenols can inhibit pancreatic lipase and consequently affect fat digestion as well as energy intake. Therefore, this study aimed to optimize the inhibitory activity of pancreatic lipase, which plays an essential role in lipid absorption. In fermented katuk (Sauropus androgynus) leaves were brewed following RSM using a Box Behnken design. Data analysis was used to optimize the formulation with a response surface model consisting of three factors namely sucrose concentration ranging from 10-20% b/v, culture 10-20 b/v, as well as fermentation time of 1-5 days. The parameters tested were the percentage inhibition of pancreatic lipase, antioxidant activity, polyphenol, and total acid. Based on the RSM optimization results obtained from the three influencing factors, the optimum conditions were established namely 10.43% w/v sucrose, 10% v/v kombucha culture, and fermentation for 5 days. These conditions yielded the most optimal responses, with the percentage inhibition of pancreatic lipase, antioxidant activity, polyphenol, and total acid being 86.13%, 96.27%, 0.97 mg GAE/mL, and 1.11%, respectively. In general, the results demons-trated that the RSM method of the Box Behnken design and the parameter prediction values obtained using the model equation are in good agreement with the experimental values with at least R2 ≥ 0.8.

Chlorophyll Inhibits the Digestion of Soybean Oil in Simulated Human Gastrointestinal System

Nowadays, much available processed and highly palatable food such as cream products and fried and convenient food, which usually showed a high energy density, had caused an increase in the intake of dietary lipids, further leading to significant growth in the prevalence of obesity. Chlorophyll, widespread in fruits and vegetables, was proven to have beneficial effects on alleviating obesity. This study investigated the effects of chlorophyll on the digestive characteristics of lipids under in vitro simulated adult and infant gastrointestinal systems. Chlorophyll decreased the release rate of free fatty acid (FFA) during in vitro adult and infant intestinal digestion by 69.2% and 60.0%, respectively. Meanwhile, after gastrointestinal digestion, chlorophyll changed the FFA composition of soybean oil emulsion and increased the particle size of oil droplets. Interestingly, with the addition of chlorophyll, the activity of pancreatic lipase was inhibited during digestion, which may be related to pheophytin (a derivative of chlorophyll after gastric digestion). Therefore, the results obtained from isothermal titration calorimetry and molecular docking further elucidated that pheophytin could bind to pancreatic lipase with a strong affinity of (4.38 ± 0.76) × 10⁷ M^-1 (K_a), while the binding site was amino acid residue Trp253. The investigation not only explained why chlorophyll inhibited digestive enzyme activity to reduce lipids digestion but also provided exciting opportunities for developing novel chlorophyll-based healthy products for dietary application in preventing obesity.

Establishment of an Efficient Polyethylene Glycol (PEG)-Mediated Transformation System in Pleurotus eryngii var. ferulae Using Comprehensive Optimization and Multiple Endogenous Promoters

Pleurotus eryngii var. ferulae, a fungus of the genus Pleurotus, efficiently degrades lignin, especially during co-cultivation with other fungi. However, low transformation efficiency and heterologous gene expression restrict systematic studies of the molecular mechanisms and metabolic control of natural products in this mushroom. In this study, the homologous resistance marker carboxin (cbx) was used to establish a polyethylene glycol-mediated transformation (PMT) system in P. eryngii var. ferulae. Optimization of the transformation process greatly improved the number of positive transformants. In particular, we optimized: (i) protoplast preparation and regeneration; (ii) screening methods; and (iii) transformation-promoting factors. The optimized transformation efficiency reached 72.7 CFU/μg, which is higher than the average level of Pleurotus sp. (10–40 CFU/μg). Moreover, three endogenous promoters (Ppfgpd1, Ppfgpd2, and Ppfsar1) were screened and evaluated for different transcription initiation characteristics. A controllable overexpression system was established using these three promoters that satisfied various heterologous gene expression requirements, such as strong or weak, varied, or stable expression levels. This study lays the foundation for recombinant protein expression in P. eryngii var. ferulae and provides a method to investigate the underlying molecular mechanisms and secondary metabolic pathway modifications.

Phytochemistry profile of rosella and jambolan extracts and the therapeutic effects on obesity

Hibiscus sabdariffa extract (HSE) and Syzygium cumini extract (SCE) have been used in traditional medicine due to their hypoglycemic, antidiabetic, anti-obesity and antioxidant activities. The aim of this study was...

Phytochemical Investigation of Bioactive Compounds from White Kidney Beans (Fruits of Phaseolus multiflorus var. Albus): Identification of Denatonium with Osteogenesis-Inducing Effect

Phaseolus multiflorus var. albus (Leguminosae), commonly known as “white kidney bean”, is a twining perennial vine whose fruit has been used as a popular food worldwide owing to its high nutritional content, in terms of proteins, carbohydrates, fats, and vitamins. As part of our ongoing study to investigate novel bioactive components from various natural resources, a phytochemical investigation of the extract of P. multiflorus var. albus fruits resulted in the isolation of three phenolic compounds (1–3) and one dipeptide (4). The chemical structures of the compounds (1–4) were determined through 1D and 2D nuclear magnetic resonance spectroscopy and high-resolution-liquid chromatography–mass spectrometry; they were identified as denatonium (1), trans-ferulic acid ethyl ester (2), eugenin (3), and α-L-glutamyl-L-Leucine (4). Intriguingly, denatonium (1) is known to be the most bitter chemical compound. To the best of our knowledge, denatonium (1) was identified from natural sources for the first time, and compounds 2–4 were reported for the first time from P. multiflorus var. albus in this study; however, compound 2 turned out to be an artifact produced by an extraction with ethanol. The isolated compounds 1–4 were tested for their regulatory effects on the differentiation between osteogenesis and adipogenesis of mesenchymal stem cells (MSCs). Compound 4 slightly suppressed the adipogenic differentiation of MSCs, and compounds 1 and 4 stimulated osteogenic differentiation, unlike the negative control. These findings provide experimental evidence that compounds 1 and 4 may induce the osteogenesis of MSCs and activate bone formation.

Evaluation of Anti-Obesity Activity of an Herbal Formulation (F2) in DIO Mice Model and Validation of UPLC-DAD Method for Quality Control

Obesity is considered a chronic metabolic disorder that can be associated with multiple medical complications. Currently, there is no or limited curative therapy for obesity. This study focused on the assessment of anti-obesity activity and UPLC standardization of a polyherbal formulation (F2). An anti-obesity activity was investigated using the diet-induced obese (DIO) mice model, where obesity was developed in C57BL/6J mice by providing a high-fat diet (HFD) for five weeks without treating drugs. After the successful development of obesity, the obese mice were treated with F2 for seven weeks with continuing HFD feeding. The major obesity-related parameters such as body weight gain, food efficiency ratio, serum lipid profile, and white adipose tissue (WAT) mass were found to be significantly reduced in F2 treated obese mice. These results were supported by the down-regulation of specific adipogenic transcription factors (PPARγ, SREBP-1c, and ap2) in epididymal WAT. Histological evaluation of liver and WAT also revealed reduced fat deposition in the tissues by F2 compared to the HFD control group. The overall observations indicated that the F2 exhibited pronounced obesity-controlling activity through the inhibition of adipocyte differentiation and triglyceride accumulation in the tissues, and serum lipid depletion. In addition, F2 ameliorated obesity-induced insulin resistance. Furthermore, the UPLC-DAD method for quality control of F2 was validated and standardized using five reference compounds: astragalin, ellagic acid, fisetin, fustin, and sulfuretin.