Pancreatic lipase inhibition of strictinin isolated from Pu’er tea (Cammelia sinensis) and its anti-obesity effects in C57BL6 mice

Synthesis, molecular modelling and pharmacological evaluation of novel indole-thiazolidinedione based hybrid analogues as potential pancreatic lipase inhibitors

A series of novel indole-thiazolidinedione hybrid analogues (7a to 7 u) were synthesised, characterised and evaluated for their potential Pancreatic Lipase (PL) inhibition. Amongst the screened analogues, 7r was found to be the most active PL inhibitor with an IC50 of 2.67 µM. Furthermore, enzyme inhibition kinetics study revealed a competitive mode of inhibition by the analogues. This fact was confirmed via fluorescence spectroscopy which further suggested the presence of one binding site for the synthesized analogues. Molecular docking was performed using human PL (PDB ID: 1LPB) and were in agreement with the in vitro results (Pearson's r = 0.8355, p < 0.05). A molecular dynamics study (100 ns) indicated that 7r was stable in a dynamic environment. The analogue 7r exhibited potential antioxidant activity and was devoid of cytotoxic effect on RAW 264.7 cells. Based on the in-vitro profiles, 7r was selected for the in-vivo pharmacological evaluation. Oral triglyceride tolerance test highlighted effect of 7r on the inhibition of triglyceride absorption. A four-week treatment of 7r in the HFD feed mice provided information regarding its anti-obesity effect with respect to parameters such as body weight, triglycerides, total cholesterol and high-density lipids. Quantification of the faecal triglyceride contents inveterates the potential role of 7r in the PL inhibition. Overall, the synthesized analogue 7r exerted an anti-obesity effect comparable to orlistat. All these results demonstrated the potential role of the newly synthesised indole-thiazolidinedione hybrid analogues in PL inhibition and may be studied further to find potential drug candidates for treating obesity.Communicated by Ramaswamy H. Sarma.

The inhibitory activity of Flos Sophorae Immaturus extract and its major flavonoid components on pancreatic lipase

Inhibition of pancreatic lipase (PL) is a strategy to prevent obesity. The inhibitory effects of Flos Sophorae Immaturus (FSI) extract and its main flavonoid components, rutin and quercetin, on PL were investigated. The contents of rutin and quercetin in FSI extract were 44.10 ± 1.33 % and 6.07 ± 1.62 %, respectively. The IC50 values of FSI extract, rutin and quercetin on PL were 322, 258 and 71 μg/mL, respectively. Rutin and quercetin inhibited PL in a reversible and noncompetitive manner. The combination of rutin and quercetin exhibited synergistic inhibitory effects at low concentration. The binding of rutin/quercetin with PL caused the fluorescence quenching of protein. Fluorescence titration showed the binding affinity of quercetin with PL protein was stronger than that of rutin. Circular dichroism analysis showed the binding changed the secondary structure of PL with an increase in random coil and a decrease in α-Helix and β-Sheet. Molecular docking revealed that rutin and quercetin could interact with the amino acid residues around the catalytic site through multiple secondary interactions. In vivo studies showed that FSI extract can reduce fat absorption and promote fecal fat excretion through inhibition of PL activity, and the effects were mainly due to rutin and quercetin.

Discovery of baicalein derivatives as novel inhibitors against human pancreatic lipase: Structure-activity relationships and inhibitory mechanisms

Human pancreatic lipase (hPL) is a vital digestive enzyme responsible for breaking down dietary fats in humans, inhibiting hPL is a feasible strategy for preventing and treating obesity. This study aims to investigate the structure-activity relationships (SARs) of flavonoids as hPL inhibitors, and to find potent hPL inhibitors from natural and synthetic flavonoids. In this work, the anti-hPL effects of forty-nine structurally diverse naturally occurring flavonoids were assessed and the SARs were summarized. The results demonstrated that the pyrogallol group on the A ring was a key moiety for hPL inhibition. Subsequently, a series of baicalein derivatives were synthesized, while 4'-amino baicalein (ABA) and 4'-pyrrolidine baicalein (PBA) were identified as novel potent hPL inhibitors (IC50 < 1 μM). Further investigations showed that scutellarein, ABA and PBA potently inhibited hPL in a non-competitive manner (Ki < 1 μM). Among all tested flavonoids, PBA showed the most potent anti-hPL effect in vitro, while this agent also exhibited favorable safety profiles, unique tissue distribution (high exposure level to intestinal system but low exposure levels to deep organs) and impressive in vivo effects for lowering blood triglyceride levels in mice. Collectively, this work uncovers the SARs of flavonoids against hPL, while a newly synthetic flavonoid (PBA) emerges as a potent hPL inhibitor with favorable safety profiles and impressive anti-hPL effects in vivo.

A computational study to probe the binding aspects of potent polyphenolic inhibitors of pancreatic lipase

Pancreatic lipase (PL) is a keen target for anti-obesity therapy that reduces dietary fat absorption. Here, we investigated the binding patterns of 220 PL inhibitors having experimental IC50 values, using molecular docking and binding energy calculations. Screening of these compounds illustrated most of them bound at the catalytic site (S1-S2 channel) and a few compounds are at the non-catalytic site (S2-S3 channel/S1-S3 channel) of PL. This binding pattern could be due to structural uniqueness or bias in conformational search. A strong correlation of pIC50 values with SP/XP docking scores, binding energies (ΔGMMGBSA) assured the binding poses are more true positives. Further, understanding of each class and subclasses of polyphenols indicated tannins preferred non-catalytic site wherein binding energies are underestimated due to huge desolvation energy. In contrast, most of the flavonoids and furan-flavonoids have good binding energies due to strong interactions with catalytic residues. While scoring functions limited the understanding of sub-classes of flavonoids. Hence, focused on 55 potent PL inhibitors of IC50 < 5 µM for better in vivo efficacy. The prediction of bioactivity, drug-likeness properties, led to 14 bioactive compounds. The low root mean square deviation (0.1-0.2 nm) of these potent flavonoids and non-flavonoid/non-polyphenols PL-inhibitor complexes during 100 ns molecular dynamics runs (MD) as well as binding energies obtained from both MD and well-tempered metadynamics, support strong binding to catalytic site. Based on the bioactivity, ADMET properties, and binding affinity data of MD and wt-metaD of potent PL-inhibitors suggests Epiafzelechin 3-O-gallate, Sanggenon C, and Sanggenofuran A shall be promising inhibitors at in vivo conditions.Communicated by Ramaswamy H. Sarma.

Role of Food Digestion and Digestive System in the Nutritional, Functional and Health Properties of Food Bioactives

The impact of food components on the human digestive system is an important area of research in the fields of nutrition and food science [...].

Important Role and Properties of Granular Nanocellulose Particles in an In Vitro Simulated Gastrointestinal System and in Lipid Digestibility and Permeability

This research evaluated the role and feasibility of the granular nanocellulose particles (GNC) from sugarcane bagasse obtained from enzymatic hydrolysis in reducing lipid digestibility and permeability in an in vitro simulated gastrointestinal (GI) system. GNC concentration (0.02%, w/v) had significantly affected the released free fatty acids (FFA), with a reduction of approximately 20%. Pickering emulsion of a GNC and olive oil simulation mixture revealed higher oil droplet size distribution and stability in the initial stage than the vortexed mixture formation. The difference in particle size distribution and zeta potential of the ingested GNC suspension and GNC-olive oil emulsion were displayed during the in vitro gastrointestinal simulation. GNC particles interacted and distributed surrounding the oil droplet, leading to interfacial emulsion. The GNC concentration (0.01-0.10%, w/v) showed low toxicity on HIEC-6 cells, ranging from 80.0 to 99% of cell viability. The release of FFA containing the ingested GNC suspension and GNC-olive oil emulsion had about a 30% reduction compared to that without the GNC digestion solution. The FFA and triglyceride permeability through the HIEC-6 intestinal epithelium monolayer were deceased in the digesta containing the ingested GNC and emulsion. This work indicated that GNC represented a significantly critical role and properties in the GI tract and reduced lipid digestion and absorption. This GNC could be utilized as an alternative food additive or supplement in fatty food for weight control due to their inhibition of lipid digestibility and assimilation.

Impact of Grape Seed Powder and Black Tea Brew on Lipid Digestion-An In Vitro Co-Digestion Study with Real Foods

Effects of two foods with bioactive constituents (black tea brew, BTB and grape seed powder, GSP) on lipid digestibility was studied. Lipolysis inhibitory effect of these foods was examined using two test foods (cream and baked beef) with highly different fatty acid (FA) composition. Digestion simulations were performed either using both gastric and pancreatic lipase, or only with pancreatic lipase according to the Infogest protocol. Lipid digestibility was assessed based on the bioaccessible FAs. Results showed the triacylglycerols containing short- and medium-chain FAs (SCFA and MCFA) are non-preferred substrates for pancreatic lipase; however, this is not characteristic for GL. Our findings suggest that both GSP and BTB primarily affect the lipolysis of SCFAs and MCFAs, because the dispreference of pancreatic lipase towards these substrates was further enhanced as a result of co-digestion. Interestingly, GSP and BTB similarly resulted in significant decrease in lipolysis for cream (containing milk fat having a diverse FA profile), whereas they were ineffective in influencing the digestion of beef fat, having simpler FA profile. It highlights that the characteristics of the dietary fat source of a meal can be a key determinant on the observed extent of lipolysis when co-digested with foods with bioactive constituents.

Strictinin: A Key Ingredient of Tea

Strictinin is a relatively tiny ellagitannin, which is found in many plants as a minor constituent. Catechins are known as the major constituents in the young leaves of most tea plants, while strictinin was found as a major constituent in the Pu'er tea plant. In some Pu'er tea varieties, strictinin was identified as the most abundant phenolic compound rather than catechins. In the past decade, strictinin was demonstrated to possess several functional activities, including antiviral, antibacterial, anti-obesity, laxative, anticaries, anti-allergic, antipsoriatic, antihyperuricemia, antidiabetic, and anticancer effects. These functional activities were in accordance with the therapeutic effects empirically perceived for Pu'er tea. Evidently, strictinin is the key ingredient in Pu'er tea that acts as a herbal medicine. In functionally-based applications, an instant powder of Pu'er tea infusion was formulated as an active raw material to be supplemented in food, cosmetics, and beverages; a new type of tea named Bitter Citrus Tzen Tea was developed by combining three teas empirically consumed to expel the cold, and new edible oral care products were designed for caries prevention by supplementation with Pu'er tea extract. More functional activities and practical applications of strictinin are scientifically anticipated in follow-up research.

Hyperoside inhibits pancreatic lipase activity in vitro and reduces fat accumulation in vivo

Hyperoside, the main component of many anti-obesity plants, might exhibit a lipase inhibition effect to reduce fat accumulation. The anti-obesity effect of hyperoside was investigated by studying its inhibitory effect and mechanism on pancreatic lipase in vitro and evaluating its ability to reduce lipid accumulation in vivo. Hyperoside is a mixed-type inhibitor of lipase with an IC₅₀ of 0.67 ± 0.02 mmol L^-in vitro. Hyperoside changed the secondary conformation of lipase, increased the α-helix content, and changed the microenvironment of lipase through static quenching. The interaction between hyperoside and lipase results from a strong binding spontaneous exothermic reaction, mainly through hydrogen bonding, van der Waals force and electrostatic force. Hyperoside protected hepatic lipid accumulation and adipose tissue hypertrophy and reduced the expression of inflammatory factors in high-fat diet-induced rats. Moreover, hyperoside had a good inhibitory effect on lipase activity in serum and increased fecal fat excretion, thereby reducing lipid absorption in vivo. This study provides theoretical support for the research and development of hyperoside in fat-reducing functional foods.

Alleviation of Hyperuricemia by Strictinin in AML12 Mouse Hepatocytes Treated with Xanthine and in Mice Treated with Potassium Oxonate

Hyperuricemia, an abnormally high level of blood uric acid, is a major risk factor for gout. Although xanthine oxidase inhibitors were clinically used to lower blood uric acid level, the concerned side effects restricted their utilization. In this study, strictinin, an abundant polyphenol in Pu'er tea, was evaluated for its preventive effects on hyperuricemia. The results showed that the xanthine oxidase activity, uric acid production, and inflammation in AML12 mouse hepatocytes treated with xanthine were significantly reduced by the supplementation of strictinin. Detailed analyses revealed that strictinin inhibited xanthine-induced NLRP3 inflammasome activation. Consistently, the elevated blood uric acid level and the enhanced xanthine oxidase activity in mice treated with potassium oxonate were effectively diminished by strictinin supplementation. Moreover, for the first time, strictinin was found to promote healthy gut microbiota. Overall, strictinin possesses a great potential to be utilized as a functional ingredient for the prevention of hyperuricemia.

Strictinin, a Major Ingredient in Yunnan Kucha Tea Possessing Inhibitory Activity on the Infection of Mouse Hepatitis Virus to Mouse L Cells

Theacrine and strictinin of Yunnan Kucha tea prepared from a mutant variety of wild Pu'er tea plants were two major ingredients responsible for the anti-influenza activity. As the COVID-19 outbreak is still lurking, developing safe and cost-effective therapeutics is an urgent need. This study aimed to evaluate the effects of these tea compounds on the infection of mouse hepatitis virus (MHV), a β-coronavirus serving as a surrogate for SARS-CoV. Treatment with strictinin (100 μM), but not theacrine, completely eliminated MHV infection, as indicated by a pronounced reduction in plaque formation, nucleocapsid protein expression, and progeny production of MHV. Subsequently, a time-of-drug addition protocol, including pre-, co-, or post-treatment, was exploited to further evaluate the possible mechanism of antiviral activity mediated by strictinin, and remdesivir, a potential drug for the treatment of SARS-CoV-2, was used as a positive control against MHV infection. The results showed that all three treatments of remdesivir (20 μM) completely blocked MHV infection. In contrast, no significant effect on MHV infection was observed when cells were pre-treated with strictinin (100 μM) prior to infection, while significant inhibition of MHV infection was observed when strictinin was introduced upon viral adsorption (co-treatment) and after viral entry (post-treatment). Of note, as compared with the co-treatment group, the inhibitory effect of strictinin was more striking in the post-treatment group. These results indicate that strictinin suppresses MHV infection by multiple mechanisms; it possibly interferes with viral entry and also critical step(s) of viral infection. Evidently, strictinin significantly inhibited MHV infection and might be a suitable ingredient for protection against coronavirus infection.

Establishment of a Cell Line Stably Expressing the Growth Hormone Secretagogue Receptor to Identify Crocin as a Ghrelin Agonist

The growth hormone secretagogue receptor-1a (GHSR1a) is the endogenous receptor for ghrelin. Activation of GHSR1a participates in many physiological processes including energy homeostasis and eating behavior. Due to its transitory half-life, the efficacy of ghrelin treatment in patients is restricted; hence the development of new adjuvant therapy is an urgent need. This study aimed to establish a cell line stably expressing GHSR1a, which could be employed to screen potential ghrelin agonists from natural compounds. First, by means of lentiviral transduction, the genome of a human HEK293T cell was modified, and a cell platform stably overexpressing GHSR1a was successfully established. In this platform, GHSR1a was expressed as a fusion protein tagged with mCherry, which allowed the monitoring of the dynamic cellular distribution of GHSR1a by fluorescent microscopy. Subsequently, the authenticity of the GHSR1a mediated signaling was further characterized by using ghrelin and teaghrelin, two molecules known to stimulate GHSR1a. The results indicated that both ghrelin and teaghrelin readily activated GHSR1a mediated signaling pathways, presumably via increasing phosphorylation levels of ERK. The specific GHSR1a signaling was further validated by using SP-analog, an antagonist of GHSR1a as well as using a cell model with the knockdown expression of GHSR1a. Molecular modeling predicted that crocin might be a potential ghrelin agonist, and this prediction was further confirmed by the established platform.

Theabrownin-targeted regulation of intestinal microorganisms to improve glucose and lipid metabolism in Goto-Kakizaki rats

Diabetes is a disease that is characterized by a disturbance of glucose metabolism. Theabrownin (TB) is one of the most active and abundant pigments in Pu-erh tea, and it is a brown pigment with multiple aromatic rings and attached residues of polysaccharides and proteins. TB has been shown to be hypolipidemic and displays fasting blood glucose (FBG)-lowering properties in rats fed a high-fat diet, but the underlying mechanism has not been elucidated. This study aimed to determine the effect of TB in treating diabetes and explore the underlying mechanism of action of intestinal microbes by using Goto-Kakizaki (GK) rats. Diabetic GK rats were treated up to 8 weeks with TB (GK-TB). Following treatment, the body weight, triglyceride (TG) content, fasting blood glucose (FBG) content, and Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) were significantly lower in the GK-TB group than in the GK control group (P < 0.05). Meanwhile, the circulating adiponectin (ADPN), leptin, and glucokinase levels in the serum of the GK-TB group were significantly higher than those in the GK group, while there was little difference in hepatic lipase (HL) and hormone-sensitive triglyceride lipase (HSL) enzyme activities (P > 0.05). Furthermore, with the extension of treatment time, the number of unique intestinal microorganisms in GK rats greatly increased and an interaction among intestinal microorganisms was observed. The Firmicutes/Bacteroides ratio was decreased significantly, and the composition of Actinobacteria and Proteobacteria was increased. The use of multiple omics technologies showed that TB is involved in the targeted regulation of the core characteristic intestinal flora including Bacteroides thetaiotaomicron (BT), Lactobacillus murinus (LM), Parabacteroides distasonis (PD), and Bacteroides_acidifaciens (BA) which improved the glucose and lipid metabolism of GK rats via the AMP-activated protein kinase signaling pathway, insulin signaling pathway, bile secretion and glycerophospholipid metabolism. Intragastric administration of BT, LM, PD, or BA led to a significantly reduced HOMA-IR in GK rats. Furthermore, BT significantly reduced serum lipid TG and total cholesterol (TC) and BA significantly reduced the serum lipid TC and low-density lipoprotein (LDL). PD significantly reduced serum LDL, while the effect of LM was not significant. However, LM and PD significantly increased the content of ADPN in serum. Taken together, our results indicated that the effect of TB on diabetic rats mainly depends on the targeted regulation of intestinal microorganisms and that TB is a functional food component with great potential to treat or prevent diabetes.

Effects and mechanisms of tea on obesity

Obesity has become a global health concern. It increases the risk of several diseases, such as type 2 diabetes mellitus, nonalcoholic fatty liver disease, and certain cancers, which threatens human health and increases social economic burden. As one of the most consumed beverages, tea contains various phytochemicals with potent bioactive properties and health-promoting effects, such as antioxidant, immune-regulation, cardiovascular protection and anticancer. Tea and its components are also considered as potential candidates for anti-obesity. Epidemiological studies indicate that regular consumption of tea is beneficial for reducing body fat. In addition, the experimental studies demonstrate that the potential anti-obesity mechanisms of tea are mainly involved in increasing energy expenditure and lipid catabolism, decreasing nutrient digestion and absorption as well as lipid synthesis, and regulating adipocytes, neuroendocrine system and gut microbiota. Moreover, most of clinical studies illustrate that the intake of green tea could reduce body weight and alleviate the obesity. In this review, we focus on the effect of tea and its components on obesity from epidemiological, experimental, and clinical studies, and discuss their potential mechanisms.

Pu'er tea rich in strictinin and catechins prevents biofilm formation of two cariogenic bacteria, Streptococcus mutans and Streptococcus sobrinus

Cariogenic bacteria, such as Streptococcus mutans and Streptococcus sobrinus, are main pathogens responsible for human dental caries. Pu'er tea is empirically observed to prevent tooth decay. Besides caffeine and catechins commonly found in oolong tea, strictinin is also found as an abundant phenolic compound in Pu'er tea. Infusion of Pu'er tea as well as single compound, strictinin, caffeine or (−)-epigallocatechin gallate (EGCG) was examined for its inhibitory effects on S. mutans and S. sobrinus. Relatively weak inhibition of bacterial growth was observed for these Pu'er tea constituents. However, biofilm formation of S. mutans or S. sobrinus was strongly prevented by the infusion of Pu'er tea as well as by strictinin or EGCG, but not caffeine. Relatively, strictinin showed a higher potency than EGCG to prevent biofilm formation. Anti-caries effect of Pu'er tea seems to be resulted from the prevention of biofilm formation of cariogenic bacteria mainly by strictinin and catechins.

Pancreatic lipase inhibitory activity of Bambusa multiplex cv. Fernleaf leaf extract in vitro and in vivo

Bambusa multiplex cv Fernleaf (B. multiplex) is a species of bamboo. In the present study, B. multiplex leaf extract was prepared through the resin absorption/desorption procedure and analyzed by HPLC. C-Glycosyl flavonoids are the main constituents of B. multiplex extract, and the content of isoorientin and vitexin was 51.8 and 23.1 mg g^-1, respectively. Besides, the extract exhibited inhibitory activities on pancreatic lipase and α-glucosidase with IC50 values of 0.91 and 1.16 mg mL^-1, respectively. The extract could bind to pancreatic lipase and showed mixed-type inhibition. An in vivo study showed that pre-administration of B. multiplex extract significantly reduced the fat absorption in rats and increased fat excretion through feces. The change in the C-glycosyl flavonoid content in feces was the same as that in the triglyceride content. The inhibitory activity of B. multiplex leaf extract on pancreatic lipase was confirmed both in vitro and in vivo.

Molecular mechanisms underlying health benefits of tea compounds

Tea is one of the three most widely consumed beverages in the world, not only because of its unique flavor but also due to its various health benefits. The bioactive components in tea, such as polyphenols, polysaccharides, polypeptides, pigments, and alkaloids, are the main contributors to its health functions. Based on epidemiological surveys, the consumption of tea and its compounds in daily life has positive effects on cardiovascular diseases, cancers, hepatopathy, obesity, and diabetes mellitus. In experimental studies, the antioxidant, anti-inflammatory, anti-cancer, anti-obesity, cardiovascular protective, liver protective, and hypoglycemic activities of tea and the related mechanisms of action have been widely investigated. The regulation of several classical signaling pathways, such as nuclear factor-κB (NF-κB), AMP activated protein kinase (AMPK), and wingless/integrated (Wnt) signaling, is involved. Clinical trials have also demonstrated the potential of tea products to be applied as dietary supplements and natural medicines. In this paper, we reviewed and discussed the recent literature on the health benefits of tea and its compounds, and specifically explored the molecular mechanisms involved.

Green Tea from the Far East to the Drug Store: Focus on the Beneficial Cardiovascular Effects

Cardiovascular diseases (CVD) are the leading cause of death worldwide. Evidence from observational and randomized controlled studies showing the potential benefits of green tea on lowering CVD risk has been emerging rapidly during the past few decades. These benefits include reduced risk for major cardiovascular events, lowering of blood pressure, decreased LDL cholesterol levels and weight loss. At the same time, the understanding of the physiological mechanisms behind these alterations is advancing. Consumption of green tea originated from China thousands of years ago, but since then, it expanded all over the world. Recent advances in understanding the role of tea polyphenols, mainly catechins, as mediators of tea's health benefits, have caused the emergence of various types of green tea extracts (GTE) on the market. While taking green tea is generally considered safe, there are concerns about the safety of using tea extracts. The present article reviews the current evidence of green tea consumption leading to reduced CVD risk, its potential biological mechanisms and the safety of using GTE.

Synthesis, molecular modelling, in vitro and in vivo evaluation of conophylline inspired novel benzyloxy substituted indole glyoxylamides as potent pancreatic lipase inhibitors

Pancreatic lipase is a digestive enzyme involved in the hydrolysis of dietary fats. Orlistat, a potent pancreatic lipase inhibitor, is widely prescribed for long-term obesity treatment. Nevertheless, orlistat is reported for severe adverse effects including hepatotoxicity and pancreatitis. In the present study, a novel series of 11 benzyloxy substituted indole glyoxylamides were designed, synthesized and evaluated for in vitro pancreatic lipase inhibitory activity. Three analogues, 10b, 11b and 11c, exhibited potent activity (IC₅₀ ≤ 2.5 µM), with 11b exhibiting a potent IC₅₀ of 1.68 µM comparable to orlistat (IC₅₀ = 0.99 µM). Further, 11b exhibited reversible competitive inhibition with an inhibitory constant value of 0.98 μM. Molecular docking of these analogues was in agreement with in vitro results, wherein the MolDock scores exhibited significant correlation with their inhibitory activity (Pearson's r = 0.7122). A 50 ns molecular dynamics simulation of 11b-pancreatic lipase complex confirmed the role of extended alkyl interactions along with π-π stacking and π-cation interactions, in stabilizing the ligand (Maximum RMSD ≈ 3 Å) in the active site. Gastro-intestinal absorption and toxicity prediction of the three potent analogues highlighted the suitability of 11b for in vivo experiments. 11b at a dose of 20 mg/kg exhibited anti-obesity efficacy comparable to orlistat (10 mg/kg), wherein the serum triglycerides were found to be 94.95 and 83.85 mg/dL, respectively. Further, faecal triglyceride quantification indicated 11b to act through pancreatic lipase inhibition similar to orlistat. The present study identified a novel pancreatic lipase inhibitory benzyloxy substituted bis(indolyl) glyoxylamide 11b, with promising anti-obesity activity.Communicated by Ramaswamy H. Sarma.

Theacrine and strictinin, two major ingredients for the anti-influenza activity of Yunnan Kucha tea

ETHNOPHARMACOLOGICAL RELEVANCE

Kucha tea plant (Camellia assamica var. kucha Chang et Wang) is regarded as a mutant variety of wild Pu'er tea plant found in few mountain areas of Yunnan, China. Its fresh young leaves and shoots are picked by the indigenous aborigines in these local areas to prepare an herbal tea for the treatment of common cold empirically.

MATERIALS AND METHODS

Two extra compounds of relative abundance were detected in Kucha tea in comparison with Pu'er tea, and their chemical structures were identified as chlorogenic acid and theacrine. These two compounds as well as two major compounds, strictinin and caffeine, in Kucha tea were evaluated for their cytotoxicity and inhibitory effects on human influenza virus A/Puerto Rico/8/34 by analyzing viral protein expression and progeny production.

RESULTS

No or low cytotoxicity was detected for the four Kucha compounds when their concentrations were below 100 μM. Expression of viral NS1 protein was significantly inhibited by chlorogenic acid, theacrine or strictinin, but not caffeine at a concentration of 100 μM. The relative inhibitory potency was detected as chlorogenic acid < theacrine < strictinin, and both theacrine and strictinin displayed significant inhibition at a concentration of 50 μM. According to a plaque assay, viral progeny production was significantly reduced by theacrine or strictinin, but not by chlorogenic acid or caffeine under the same concentration of 100 μM.

CONCLUSION

It is suggested that theacrine and strictinin are two major ingredients responsible for the anti-influenza activity of Yunnan Kucha tea traditionally used for the treatment of common cold.

Characterisation of teaghrelin-like principles from Assam tea cultivated in Thailand

Teaghrelins were identified as unique acylated flavonoid tetraglycosides and firstly reported in Chin-shin oolong tea. In the present study, two new teaghrelin-like compounds (1 and 2) were purified and characterised from Assam tea varieties collected in Thailand. Their chemical structures were constructed by the spectroscopic and spectrometric analysis. These two teaghrelin-like compounds were also not supposed to exhibit significant ghrelin receptor affinity according to the structural comparison with those teaghrelin-like compounds previously reported. In addition, compounds 1 and 2 did not display notable anti-inflammatory activity in human neutrophils assay.[Formula: see text].

Review of Distribution, Extraction Methods, and Health Benefits of Bound Phenolics in Food Plants

Phenolic compounds are important functional bioactive substances distributed in various food plants. They have gained wide interest from researchers due to their multiple health benefits. There are two forms of phenolic compounds: free form and bound form. The latter is also called bound phenolics (BPs), which are found mainly in the cell wall and distributed in various tissues/organs of the plant body. They can either chemically bind to macromolecules and food matrixes or be physically entrapped in food matrixes and intact cells. Various isolation methods, including chemical, biological, and physical methods, have been employed to extract BPs from plants. BPs have been shown to have strong biological activities, including antioxidant, probiotic, anticancer, anti-inflammation, antiobesity, and antidiabetic effects as well as beneficial effects on central nervous system diseases. This review summarizes research findings on these topics to help in better understanding of BPs and provide comprehensive information on their health effects.

Chemical profile changes during pile fermentation of Qingzhuan tea affect inhibition of α-amylase and lipase

Qingzhuan tea (QZT), a post-fermented tea, has been reported to have anti-obesity and anti-hyperglycemic effects, perhaps due to bioactive compounds that inhibit lipase and α-amylase. It is unknown what chemical constituents’ changes and what bioactive compounds occur during the manufacture of QZT. The aim of this study was to determine the secondary metabolites changes that occur during post-fermentation and how these changes affect the ability of QZT to inhibit the activities of lipase and α-amylase. During the processing steps, metabolites levels and their inhibitory effects on lipase and α-amylase were assessed. Changes in content and activities suggested that the first turn over or the second turn over was critical for the formation and conversion of bioactive compounds responsible for the anti-obesity and hypoglycemic effects. The relationship between constituents and activities was further evaluated by correlation analysis, which showed that amino acids and flavonoids might be responsible for the anti-obesity and anti-hyperglycemic effects of QZT. This study clarified that compounds were altered during pile fermentation of QZT and tentatively identified the bioactive compounds formed during QZT manufacture.

Characterization of teaghrelin-like compounds from tea cultivars

Teaghrelins, identified originally in Chin-shin oolong tea, are unique acylated flavonoid tetraglycosides and proposed to be potential oral analogues of ghrelin. In the present study, two new teaghrelin-like compounds were characterized from tea cultivars (TTES No. 12), and their chemical structures were established by the spectroscopic and spectrometric analysis. However, due to the different location of rhamnose, these two teaghrelin-like compounds may not show significant ghrelin receptor affinity.[Figure: see text].

Identification of two teaghrelins in Shy-jih-chuen oolong tea

Teaghrelins are unique acylated flavonoid tetraglycosides originally identified in Chin-shin oolong tea, and proposed to be potential oral analogs of ghrelin. Two acylated flavonoid tetraglycosides were isolated from Shy-jih-chuen oolong tea, and their chemical structures were determined to be quercetin and kaempferol 3-O-[α-L-arabinopyranosyl(1 → 3)][2"-O-(E)-p-coumaroyl] [β-D-glucopyranosyl(1 → 3)-α-L-rhamnopyranosyl(1 → 6)]-β-D-glucoside. These two compounds were extremely similar to the two teaghrelins (teaghrelin-1 and teaghrelin-2) in Chin-shin oolong tea by simply replacing a glucopyranosyl group with an arabinopyranosyl group. Molecular modeling showed that the two putative teaghrelins identified in Shy-jih-chuen docked to and interacted with the ghrelin receptor as well as teaghrelin-1 and teaghrelin-2. Mixture of these two putative teaghrelins was shown to enhance the release of growth hormone from primary anterior pituitary cells of rats. The results suggest that two teaghrelins, named teaghrelin-3 and teaghrelin-4, are present in Shy-jih-chuen oolong tea and possess biological activities analogous to teaghrelins in Chin-shin oolong tea. PRACTICAL APPLICATIONS: According to this study, teaghrelin-3 and teaghrelin-4 may be regarded as active ingredients for the quality control of Shy-jih-chuen oolong tea. The content of teaghrelins may serve as a key factor for the farmers to select new tea plants in their next propagation of Shy-jih-chuen cultivar. Crude water extract of Shy-jih-chuen oolong tea containing teaghrelins is considered to be an adequate food supplement or additive in functional food products.

Cyanidin and cyanidin-3-glucoside derived from Vigna unguiculata act as noncompetitive inhibitors of pancreatic lipase

The consumption of legumes positively correlated with the reduction of body weight. In the present study, we identified and evaluated pancreatic lipase inhibitors from Vigna unguiculata and unraveled their mode of inhibition. The highly sensitive fluorometric method was adopted to access the pancreatic lipase activity and the ethanolic extract of Vigna unguiculata showed the maximum inhibition (IC₅₀ of 15.2 µg/ml). Cyanidin and cyanidin-3-glucoside are the major anthocyanins observed in Vigna unguiculata. The IC₅₀ value of cyanidin was 28.29 µM which was 6.5-fold higher than the cyanidin-3-glucoside (188.28 µM). We determined an apparent K_i of 27.28 µM for cyanidin and cyanidin-3-glucoside (88.97 µM) with noncompetitive inhibition. Collectively, these results suggest that the glycosylation of the anthocyanidins significantly reduces lipase inhibition. The noncompetitive inhibition of pancreatic lipase by Vigna unguiculata anthocyanins may exert significant pharmacological activities toward obesity complications by calorie restriction. PRACTICAL APPLICATIONS: The results of this study emphasize the importance of legumes in our diet to combat obesity-related complications. Consumption of legumes minimizes fat absorption by inhibiting the action of the fat-digesting enzyme.

Determination of Key Active Components in Different Edible Oils Affecting Lipid Accumulation and Reactive Oxygen Species Production in HepG2 Cells

Owing to the poor ability of cells to decompose triglycerides, most studies of edible oil have depended on animal or clinical trials. However, such trials are expensive and time-consuming, and the results are limited to considerable individual differences. This is the first study to comprehensively investigate the effect of different oils on the lipid accumulation and reactive oxygen species (ROS) production in HepG2 cells by hydrolyzing oil to fatty acids with integrated fat content. In addition, the key components of fatty acid composition, phytosterol, polyphenols, and tocopherol/tocotrienol in different oils, contributing to a decrease in content of lipid accumulation, cholesterol, ROS, and malondialdehyde (MDA), were analyzed using multivariate analysis. The results showed that the lipid accumulation content of coconut oil, Pu'er tea oil, olive oil, and flaxseed oil at a concentration of 200 μM decreased by 45.98 ± 0.75, 50.35 ± 1.37, 40.43 ± 2.44, and 42.76 ± 1.88%, respectively, compared with the lard. In addition, the ROS contents of Pu'er tea oil, olive oil, and flaxseed oil had no significant difference from that of control cells ( p < 0.05). In the results, (3β,5α)-stigmastan-3-yl, cholane-5,20(22)-diene-3b-ph, and β-sitosterol were determined to be the key components in edible oils associated with lipid accumulation and ROS production.