Discovery of a botanical compound as a broad-spectrum inhibitor against gut microbial ß-glucuronidases from the Tibetan medicine Rhodiola crenulata.

Gut microbial ß-glucuronidases (gmß-GUS) played crucial roles in regulating a variety of endogenous substances and xenobiotics on the circulating level, thus had been recognized as key modulators of drug toxicity and human diseases. Inhibition or inactivation of gmß-GUS enzymes has become a promising therapeutic strategy to alleviate drug-induced intestinal toxicity. Herein, the Rhodiola crenulata extract (RCE) was found with potent and broad-spectrum inhibition on multiple gmß-GUS enzymes. Subsequently, the anti-gmß-GUS activities of the major constituents in RCE were tested and the results showed that 1,2,3,4,6-penta-O-galloyl-ß-d-glucopyranose (PGG) acted as a strong and broad-spectrum inhibitor on multiple gmß-GUS (including EcGUS, CpGUS, SaGUS, and EeGUS). Inhibition kinetic assays demonstrated that PGG effectively inhibited four gmß-GUS in a non-competitive manner, with the Ki values ranging from 0.12 µM to 1.29 µM. Docking simulations showed that PGG could tightly bound to the non-catalytic sites of various gmß-GUS, mainly via hydrogen bonding and aromatic interactions. It was also found that PGG could strongly inhibit the total gmß-GUS activity in mice feces, with the IC50 value of 1.24 µM. Collectively, our findings revealed that RCE and its constituent PGG could strongly inhibit multiple gmß-GUS enzymes, suggesting that RCE and PGG could be used for alleviating gmß-GUS associated enterotoxicity.

Uncovering the anti-obesity constituents in Ginkgo biloba extract and deciphering their synergistic effects.

Obesity has been recognized as a key risk factor for multiple metabolic disorders, including diabetes, cardiovascular diseases and many types of cancer. Herbal medicines have been frequently used for preventing and treating obesity in many countries, but in most cases, the key anti-obesity constituents in herbs and their anti-obesity mechanisms are poorly understood. This study demonstrated a case study for uncovering the anti-obesity constituents in an anti-obesity herbal medicine (Ginkgo biloba extract) and deciphering their synergistic effects via targeting human pancreatic lipase (hPL). Following screening the anti-hPL effects of eighty herbal medicines, Ginkgo biloba extract (GBE50) was found with the most potent anti-hPL activity. Global chemical profiling of herbal constituents coupling with hPL inhibition assay revealed that the bioflavonoids and several flavonoids in GBE50 were key anti-hPL constituents. Among all tested thirty-eight constituents, sciadopitysin, bilobetin, quercetin, isoginkgetin, and ginkgetin showed potent anti-hPL effects (IC50 values <2.5 µM). Inhibition kinetic analyses suggested that sciadopitysin, bilobetin, quercetin, isoginkgetin, and ginkgetin acted as non-competitive inhibitors of hPL, with the Ki values were <2 µM. Docking simulations revealed that four bioflavonoids (sciadopitysin, bilobetin, isoginkgetin, and ginkgetin) could tightly bind on hPL at cavity 2, which it is different from the binding cavity of quercetin on hPL. Further investigations demonstrated that the combinations of quercetin and one bioflavonoid-type hPL inhibitor (sciadopitysin or bilobetin) showed synergistic anti-hPL effects, suggesting that the multi-components in GBE50 may generate more potent anti-hPL effect. Collectively, our findings uncovered the anti-obesity constituents in GBE50, and explored their anti-hPL mechanisms as well as synergistic effects at molecular levels, which will be very helpful for further understanding the anti-obesity mechanisms of Ginkgo biloba.

Human Carboxylesterase 1A Plays a Predominant Role in Hydrolysis of the Anti-Dyslipidemia Agent Fenofibrate in Humans.

Fenofibrate, a marketed peroxisome proliferator-activated receptor-α (PPARα) agonist, has been widely used for treating severe hypertriglyceridemia and mixed dyslipidemia. As a canonical prodrug, fenofibrate can be rapidly hydrolyzed to release the active metabolite (fenofibric acid) in vivo, but the crucial enzyme(s) responsible for fenofibrate hydrolysis and the related hydrolytic kinetics have not been well-investigated. This study aimed to assign the key organs and crucial enzymes involved in fenofibrate hydrolysis in humans, as well as reveal the impact of fenofibrate hydrolysis on its non-PPAR-mediated biologic activities. Our results demonstrated that fenofibrate could be rapidly hydrolyzed in the preparations from both human liver and lung to release fenofibric acid. Reaction phenotyping assays coupling with chemical inhibition assays showed that human carboxylesterase 1A (hCES1A) played a predominant role in fenofibrate hydrolysis in human liver and lung, while human carboxylesterase 2A (hCES2A) and human monoacylglycerol esterase (hMAGL) contributed to a very lesser extent. Kinetic analyses showed that fenofibrate could be rapidly hydrolyzed by hCES1A in human liver preparations, while the inherent clearance of hCES1A-catalyzed fenofibrate hydrolysis is much higher (>200-fold) than than that of hCES2A or hMAGL. Biologic assays demonstrated that both fenofibrate and fenofibric acid showed very closed Nrf2 agonist effects, but fenofibrate hydrolysis strongly weakens its inhibitory effects against both hCES2A and hNtoum. Collectively, our findings reveal that the liver is the major organ and hCES1A is the predominant enzyme-catalyzing fenofibrate hydrolysis in humans, while fenofibrate hydrolysis significantly reduces inhibitory effects of fenofibrate against serine hydrolases. SIGNIFICANCE STATEMENT: Fenofibrate can be completely converted to fenofibric acid in humans and subsequently exert its pharmacological effects, but the hydrolytic pathways of fenofibrate in humans have not been well-investigated. This study reported that the liver was the predominant organ and human carboxylesterase 1A was the crucial enzyme involved in fenofibrate hydrolysis in humans.

A rationally engineered specific near-infrared fluorogenic substrate of human pancreatic lipase for functional imaging and inhibitor screening.

Obesity, now widespread all over the world, is frequently associated with several chronic diseases. Human pancreatic lipase (hPL) is a crucial digestive enzyme responsible for the digestion of dietary lipids in humans, and the inhibition of hPL is effective in reducing triglyceride intake and thus preventing and treating obesity. In this work, a practical sequential screening strategy was developed to construct a highly selective near-infrared fluorogenic substrate 7-STCFC for hPL. Under physiological conditions, 7-STCFC can be rapidly hydrolyzed by hPL to form 7-HTCFC, which triggers 254-fold NIR signal enhancement at 670 nm. 7-STCFC was successfully applied for the sensing and imaging of endogenous PL in living systems (including living cells, tissues and organs) with low cytotoxicity and high imaging resolution. Moreover, a high-throughput screening platform was established using 7-STCFC, and the inhibitory effects of 94 kinds of herbs toward hPL were evaluated. Among them, Pu-erh tea stood out with outstanding hPL inhibitory effects, and the inhibitory ingredients and involved inhibitory mechanism were further revealed, which strongly facilitates the discovery of novel anti-obesity agents targeting hPL. Collectively, these findings suggested that our strategy was practical to develop an isoform-specific fluorogenic substrate for a target enzyme, and 7-STCFC was a powerful tool for monitoring PL activity in complex biological systems with value for exploring physiological functions and rapid screening of inhibitors.

Small intestinal angiosarcoma on clinical presentation, diagnosis, management and prognosis: A case report and review of the literature.

BACKGROUND: Angiosarcoma is a highly malignant soft-tissue sarcoma derived from vascular endothelial cells that mainly occurs in the skin and subcutaneous tissues. Small-intestinal angiosarcomas are rare, and the prognosis is poor. CASE SUMMARY: We reported a case of primary multifocal ileal angiosarcoma and analyze previously reported cases to improve our understanding of small intestinal angiosarcoma. Small intestinal angiosarcoma is more common in elderly and male patients. Gastrointestinal bleeding, anemia, abdominal pain, weakness, and weight loss were the common symptoms. CD31, CD34, factor VIII-related antigen, ETS-related gene, friend leukemia integration 1, and von Willebrand factor are valuable immunohistochemical markers for the diagnosis of small-intestinal angiosarcoma. Small-intestinal angiosarcoma most commonly occurs in the jejunum, followed by the ileum and duodenum. Radiation and toxicant exposure are risk factors for angiosarcoma. After a definite diagnosis, the mean and median survival time was 8 mo and 3 mo, respectively. Kaplan-Meier survival analysis showed that age, infiltration depth, chemotherapy, and the number of small intestinal segments invaded by tumor lesions were prognostic factors for small intestinal angiosarcoma. Multivariate Cox regression analysis showed that chemotherapy and surgery significantly improved patient prognosis. CONCLUSION: Angiosarcoma should be considered for unexplained melena and abdominal pain, especially in older men and patients with a history of radiation exposure. Prompt treatment, including surgery and adjuvant chemotherapy, is essential to prolonging patient survival.

Discovery of human pancreatic lipase inhibitors from root of Rhodiola crenulata via integrating bioactivity-guided fractionation, chemical profiling and biochemical assay.

Although herbal medicines (HMs) are widely used in the prevention and treatment of obesity and obesity-associated disorders, the key constituents exhibiting anti-obesity activity and their molecular mechanisms are poorly understood. Recently, we assessed the inhibitory potentials of several HMs against human pancreatic lipase (hPL, a key therapeutic target for human obesity), among which the root-extract of Rhodiola crenulata (ERC) showed the most potent anti-hPL activity. In this study, we adopted an integrated strategy, involving bioactivity-guided fractionation techniques, chemical profiling, and biochemical assays, to identify the key anti-hPL constituents in ERC. Nine ERC fractions (retention time = 12.5-35 min), obtained using reverse-phase liquid chromatography, showed strong anti-hPL activity, while the major constituents in these bioactive fractions were subsequently identified using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-Q-TOF-MS/MS). Among the identified ERC constituents, 1,2,3,4,6-penta-O-galloyl-ß-d-glucopyranose (PGG) and catechin gallate (CG) showed the most potent anti-hPL activity, with pIC50 values of 7.59 ± 0.03 and 7.68 ± 0.23, respectively. Further investigations revealed that PGG and CG potently inhibited hPL in a non-competitive manner, with inhibition constant (K i) values of 0.012 and 0.082 µM, respectively. Collectively, our integrative analyses enabled us to efficiently identify and characterize the key anti-obesity constituents in ERC, as well as to elucidate their anti-hPL mechanisms. These findings provide convincing evidence in support of the anti-obesity and lipid-lowering properties of ERC.

Discovery and Characterization of the Naturally Occurring Inhibitors Against Human Pancreatic Lipase in Ampelopsis grossedentata.

Pancreatic lipase (PL) inhibitor therapy has been validated as an efficacious way for preventing and treating obesity and overweight. In the past few decades, porcine PL (pPL) is widely used as the enzyme source for screening the PL inhibitors, which generates a wide range of pPL inhibitors. By contrast, the efficacious inhibitors against human PL (hPL) are rarely reported. This study aims to discover the naturally occurring hPL inhibitors from edible herbal medicines (HMs) and to characterize the inhibitory mechanisms of the newly identified hPL inhibitors. Following the screening of the inhibition potentials of more than 100 HMs against hPL, Ampelopsis grossedentata extract (AGE) displayed the most potent hPL inhibition activity. After that, the major constituents in AGE were identified and purified, while their anti-hPL effects were assayed in vitro. The results clearly showed that two abundant constituents in AGE (dihydromyricetin and iso-dihydromyricetin) were moderate hPL inhibitors, while myricetin and quercetin were strong hPL inhibitors [half-maximal inhibitory concentration (IC 50) values were around 1.5 µM]. Inhibition kinetic analyses demonstrated that myricetin and quercetin potently inhibited hPL-catalyzed near-infrared fluorogenic substrate of human pancreatic lipase (DDAO-ol) hydrolysis in a non-competitive inhibition manner, with K i values of 2.04 and 2.33 µM, respectively. Molecular dynamics simulations indicated that myricetin and quercetin could stably bind on an allosteric site of hPL. Collectively, this study reveals the key anti-obesity constituents in AGE and elucidates their inhibitory mechanisms against hPL, which offers convincing evidence to support the anti-obesity and lipid-lowering effects of this edible herb.

Discovery of human pancreatic lipase inhibitors from root of Rhodiola crenulata via integrating bioactivity-guided fractionation,chemical profiling and biochemical assay / 药物分析学报

Although herbal medicines(HMs)are widely used in the prevention and treatment of obesity and obesity-associated disorders,the key constituents exhibiting anti-obesity activity and their molecular mechanisms are poorly understood.Recently,we assessed the inhibitory potentials of several HMs against human pancreatic lipase(hPL,a key therapeutic target for human obesity),among which the root-extract of Rhodiola crenulata(ERC)showed the most potent anti-hPL activity.In this study,we adopted an integrated strategy,involving bioactivity-guided fractionation techniques,chemical profiling,and biochemical assays,to identify the key anti-hPL constituents in ERC.Nine ERC fractions(retention time=12.5-35 min),obtained using reverse-phase liquid chromatography,showed strong anti-hPL activity,while the major constituents in these bioactive fractions were subsequently identified using liquid chromatography-quadrupole time-of-flight mass spectrometry(LC-Q-TOF-MS/MS).Among the identified ERC constituents,1,2,3,4,6-penta-O-galloyl-β-D-glucopyranose(PGG)and catechin gallate(CG)showed the most potent anti-hPL activity,with pIC50 values of 7.59±0.03 and 7.68±0.23,respectively.Further investigations revealed that PGG and CG potently inhibited hPL in a non-competitive manner,with inhibition constant(Ki)values of 0.012 and 0.082 μM,respectively.Collectively,our integrative analyses enabled us to efficiently identify and characterize the key anti-obesity constituents in ERC,as well as to elucidate their anti-hPL mechanisms.These findings provide convincing evidence in support of the anti-obesity and lipid-lowering properties of ERC.

Ethnopharmacology, chemodiversity, and bioactivity of Cephalotaxus medicinal plants.

Cephalotaxus is the only genus of Cephalotaxaceae family, and its natural resources are declining due to habitat fragmentation, excessive exploitation and destruction. In many areas of China, folk herbal doctors traditionally use Cephalotaxus plants to treat innominate swollen poison, many of which are cancer. Not only among Han people, but also among minority ethnic groups, Cephalotaxus is used to treat various diseases, e.g., cough, internal bleeding and cancer in Miao medicine, bruises, rheumatism and pain in Yao medicine, and ascariasis, hookworm disease, scrofula in She medicine, etc. Medicinal values of some Cephalotaxus species and compounds are acknowledged officially. However, there is a lack of comprehensive review summarizing the ethnomedicinal knowledge of Cephalotaxus, relevant medicinal phytometabolites and their bioactivities. The research progresses in ethnopharmacology, chemodiversity, and bioactivities of Cephalotaxus medicinal plants are reviewed and commented here. Knowledge gaps are pinpointed and future research directions are suggested. Classic medicinal books, folk medicine books, herbal manuals and ethnomedicinal publications were reviewed for the genus Cephalotaxus (Sanjianshan in Chinese). The relevant data about ethnobotany, phytochemistry, and pharmacology were collected as comprehensively as possible from online databases including Scopus, NCBI PubMed, Bing Scholar, and China National Knowledge Infrastructure (CNKI). "Cephalotaxus", and the respective species name were used as keywords in database search. The obtained articles of the past six decades were collated and analyzed. Four Cephalotaxus species are listed in the official medicinal book in China. They are used as ethnomedicines by many ethnic groups such as Miao, Yao, Dong, She and Han. Inspirations are obtained from traditional applications, and Cephalotaxus phytometabolites are developed into anticancer reagents. Cephalotaxine-type alkaloids, homoerythrina-type alkaloids and homoharringtonine (HHT) are abundant in Cephalotaxus, e.g., C. lanceolata, C. fortunei var. alpina, C. griffithii, and C. hainanensis, etc. New methods of alkaloid analysis and purification are continuously developed and applied. Diterpenoids, sesquiterpenoids, flavonoids, lignans, phenolics, and other components are also identified and isolated in various Cephalotaxus species. Alkaloids such as HHT, terpenoids and other compounds have anticancer activities against multiple types of human cancer. Cephalotaxus extracts and compounds showed anti-inflammatory and antioxidant activities, immunomodulatory activity, antimicrobial activity and nematotoxicity, antihyperglycemic effect, and bone effect, etc. Drug metabolism and pharmacokinetic studies of Cephalotaxus are increasing. We should continue to collect and sort out folk medicinal knowledge of Cephalotaxus and associated organisms, so as to obtain new enlightenment to translate traditional tips into great therapeutic drugs. Transcriptomics, genomics, metabolomics and proteomics studies can contribute massive information for bioactivity and phytochemistry of Cephalotaxus medicinal plants. We should continue to strengthen the application of state-of-the-art technologies in more Cephalotaxus species and for more useful compounds and pharmacological activities.

Beta-Glucuronidase Inhibition by Constituents of Mulberry Bark.

Intestinal bacterial ß-glucuronidases, the key enzymes responsible for the hydrolysis of various glucuronides into free aglycone, have been recognized as key targets for treating various intestinal diseases. This study aimed to investigate the inhibitory effects and mechanisms of the Mulberry bark constituents on E. coli ß-glucuronidase (EcGUS), the most abundant ß-glucuronidases produced by intestinal bacteria. The results showed that the flavonoids isolated from Mulberry bark could strongly inhibit E. coli ß-glucuronidase, with IC50 values ranging from 1.12 µM to 10.63 µM, which were more potent than D-glucaric acid-1,4-lactone. Furthermore, the mode of inhibition of 5 flavonoids with strong E. coli ß-glucuronidase inhibitory activity (IC50 ≤ 5 µM) was carefully investigated by a set of kinetic assays and in silico analyses. The results demonstrated that these flavonoids were noncompetitive inhibitors against E. coli ß-glucuronidase-catalyzed 4-nitrophenyl ß-D-glucuronide hydrolysis, with Ki values of 0.97 µM, 2.71 µM, 3.74 µM, 3.35 µM, and 4.03 µM for morin (1: ), sanggenon C (2: ), kuwanon G (3: ), sanggenol A (4: ), and kuwanon C (5: ), respectively. Additionally, molecular docking simulations showed that all identified flavonoid-type E. coli ß-glucuronidase inhibitors could be well-docked into E. coli ß-glucuronidase at nonsubstrate binding sites, which were highly consistent with these agents' noncompetitive inhibition mode. Collectively, our findings demonstrated that the flavonoids in Mulberry bark displayed strong E. coli ß-glucuronidase inhibition activity, suggesting that Mulberry bark might be a promising dietary supplement for ameliorating ß-glucuronidase-mediated intestinal toxicity.

Design, synthesis and biological evaluation of novel chalcone-like compounds as potent and reversible pancreatic lipase inhibitors.

Pancreatic lipase (PL), a crucial enzyme responsible for hydrolysis of dietary lipids, has been validated as a key therapeutic target to prevent and treat obesity-associated metabolic disorders. Herein, we report the design, synthesis and biological evaluation of a series of chalcone-like compounds as potent and reversible PL inhibitors. Following two rounds of structural modifications at both A and B rings of a chalcone-like skeleton, structure-PL inhibition relationships of the chalcone-like compounds were studied, while the key substituents that would be beneficial for PL inhibition were revealed. Among all tested chalcone-like compounds, compound B13 (a novel chalcone-like compound bearing two long carbon chains) displayed the most potent PL inhibition activity, with an IC50 value of 0.33 µM. Inhibition kinetic analyses demonstrated that B13 could potently inhibit PL-mediated 4-MUO hydrolysis in a mixed inhibition manner, with the Ki value of 0.12 µM. Molecular docking simulations suggested that B13 could tightly bind on PL at both the catalytic site and a non-catalytic site that was located on the surface of PL, which was consistent with the mixed inhibition mode of this agent. In addition, B13 displayed excellent stability in artificial gastrointestinal fluids and good metabolic stability in human liver preparations. Collectively, our findings suggested that chalcone-like compounds were good choices for design and development of orally administrated PL inhibitors, while B13 could be served as a promising lead compound to develop novel anti-obesity agents via targeting on PL.

Pancreatic lipase inhibitory constituents from Fructus Psoraleae.

Pancreatic lipase (PL), a crucial enzyme in the digestive system of mammals, has been proven as a therapeutic target to prevent and treat obesity. The purpose of this study is to evaluate and characterize the PL inhibition activities of the major constituents from Fructus Psoraleae (FP), one of the most frequently used Chinese herbs with lipid-lowering activity. To this end, a total of eleven major constituents isolated from Fructus Psoraleae have been obtained and their inhibition potentials against PL have been assayed by a fluorescence-based assay. Among all tested compounds, isobavachalcone, bavachalcone and corylifol A displayed strong inhibition on PL (IC50 < 10 µmol·L-1). Inhibition kinetic analyses demonstrated that isobavachalcone, bavachalcone and corylifol A acted as mixed inhibitors against PL-mediated 4-methylumbelliferyl oleate (4-MUO) hydrolysis, with the Ki values of 1.61, 3.77 and 10.16 µmol·L-1, respectively. Furthermore, docking simulations indicated that two chalcones (isobavachalcone and bavachalcone) could interact with the key residues located in the catalytic cavity of PL via hydrogen binding and hydrophobic interactions. Collectively, these finding provided solid evidence to support that Fructus Psoraleae contained bioactive compounds with lipid-lowering effects via targeting PL, and also suggested that the chalcones in Fructus Psoraleae could be used as ideal leading compounds to develop novel PL inhibitors.

A high-resolution summary of Cambrian to Early Triassic marine invertebrate biodiversity.

One great challenge in understanding the history of life is resolving the influence of environmental change on biodiversity. Simulated annealing and genetic algorithms were used to synthesize data from 11,000 marine fossil species, collected from more than 3000 stratigraphic sections, to generate a new Cambrian to Triassic biodiversity curve with an imputed temporal resolution of 26 ± 14.9 thousand years. This increased resolution clarifies the timing of known diversification and extinction events. Comparative analysis suggests that partial pressure of carbon dioxide (Pco2) is the only environmental factor that seems to display a secular pattern similar to that of biodiversity, but this similarity was not confirmed when autocorrelation within that time series was analyzed by detrending. These results demonstrate that fossil data can provide the temporal and taxonomic resolutions necessary to test (paleo)biological hypotheses at a level of detail approaching those of long-term ecological analyses.

Inhibition of pancreatic lipase by the constituents in St. John's Wort: In vitro and in silico investigations.

Herbal medicines are frequently used for the prevention and treatment of obesity and obesity-related disorders. Our preliminary screening showed that St. John's Wort (SJW) displayed potent inhibition on pancreatic lipase (PL), a key hydrolase responsible for lipid digestion and absorption in mammals. Herein, the inhibition potentials and inhibitory mechanism of SJW extract and its major constituents on PL were fully investigated by a set of in vitro and in silico studies. The results clearly demonstrated that the naphthodianthrones, biflavones and most of flavonoids in SJW displayed strong to moderate inhibition on PL. Among all tested natural compounds, two naphthodianthrones (hypericin and pseudohypericin) and one biflavone (I3,II8-biapigenin) isolated from SJW exhibited potent PL inhibition activity, with the IC50 values of <1 µM. Inhibition kinetics analyses showed that hypericin, pseudohypericin and I3,II8-biapigenin inhibited PL via a mixed manner, while molecular dynamics simulations revealed that three newly identified PL inhibitors could bind on PL at both the catalytic cavity and the interface between colipase and the C-terminal domain of PL. Collectively, our findings suggested that part of major constituents in SJW displayed potent PL inhibition activities, which could be used as lead compounds for the development of novel PL inhibitors.

Mechanism and Selectivity of the Oxidative Ring Contraction of Cyclic α-Formyl Ketones.

The oxidative contraction of α-formal ketone to form continuous all carbon chiral centers promoted by H2 O2 is widely used in natural product total synthesis. Typically, using this transformation, chiral cyclic ketones are obtained as the major products and ring-opening products as the minor products. Herein, DFT calculations have been used to investigate the detailed reaction mechanism and chemoselectivity. In addition, with the widely accepted mechanism of H2 O2 -promoted transformation, our systematic investigation with various explicit-solvent-model calculations for the first time shows that H2 O and H2 O2 are comparable at catalyzing the rate-determining step of this reaction, which emphasis the importance of solvent effect in such transformations. It is found that both the less ring-constrain and a later transition state in an exothermic reaction account for the origin why the reaction favors ring-contraction pathway rather than ring-opening one. By a comprehensive analysis for the substituted groups, it has been disclosed that the steric effects of the substituted groups on R2 and R3 contribute to the selectivity with larger steric hindrance favoring the chiral cyclic products. Moreover, the electronic effects on R1 but not R3 affect the selectivity with electron-donating groups leading to the cyclic products. Based on our calculations, some predictions for higher selectivity have been made.

Natural constituents from Cortex Mori Radicis as new pancreatic lipase inhibitors.

Pancreatic lipase (PL), a key enzyme responsible for the hydrolysis of triacylglycerides in the gastrointestinal tract, has been identified as the therapeutic target for the regulation of lipid absorption. In the present study, six major constituents from a famous Chinese herbal medicine Cortex Mori Radicis (also named sangbaipi in Chinese), have been collected and their inhibitory effects on PL have been carefully investigated and well characterized by a fluorescence-based assay. The results clearly demonstrated that all tested bioactive constituents from Cortex Mori Radicis including sanggenone C (SC), sanggenone D (SD), kuwanon C (KC), kuwanon G (KG), morin and morusin displayed strong to moderate inhibitory effects towards PL with the IC50 values ranging from 0.77 µM to 20.56 µM. Further investigations on inhibition kinetics demonstrated that SC, SD, KC and KG functioned as potent and mixed inhibitors against PL-mediated 4-MU oleate hydrolysis, with the Ki values less than 5.0 µM. Furthermore, molecular docking simulations demonstrated that SD (the most potent PL inhibitor from Cortex Mori Radicis) could create strong interaction with Ser152 (the key amino acid in the catalytic triad) of PL via hydrogen bonding. All these findings provided a new powerful evidence for explaining the hypolipidemic effect of Cortex Mori Radicis, also suggested that some abundant natural compounds in this herbal medicine could be served as lead compounds for the development of new PL inhibitors.

Biflavones from Ginkgo biloba as novel pancreatic lipase inhibitors: Inhibition potentials and mechanism.

Reduction of lipid absorption has been recognized as an attractive approach for the discovery of new drugs to treat obesity and overweight. The leave extract of Ginkgo biloba has been widely used for the treatment of metabolic diseases (such as hyperlipidemia) in both eastern and western countries, but the bioactive compounds in Ginkgo biloba and the underlying mechanism have not been fully characterized. This study aimed to investigate the inhibition potentials and mechanism of major biflavones from G. biloba on pancreatic lipase (PL), a key target regulating lipid absorption. The results clearly demonstrated that all tested biflavones in G. biloba including isoginkgetin, bilobetin, ginkgetin and sciadopitysin, displayed strong to moderate inhibitory effects on PL with the IC50 values ranging from 2.90 µM to 12.78 µM. Further investigations on both inhibition kinetic analyses and docking simulations demonstrated that isoginkgetin, bilobetin and ginkgetin were potent PL inhibitors (Ki < 2.5 µM), which could create strong interactions with the catalytic triad of PL via hydrogen bonding. These findings provided a new powerful evidence for explaining the hypolipidemic effects of G. biloba, while these newly identified PL inhibitors from G. biloba could serve as lead compounds for the development of biflavonoid-type PL inhibitors.

Effect of tissue factor knockdown on the growth, invasion, chemoresistance and apoptosis of human gastric cancer cells.

This study aimed to explore the role of tissue factor (TF) and evaluate its antitumor effects in the biological processes of gastric cancer cells using the application of RNA interference technology to silence TF in the SGC7901 gastric cancer cell line. Specific small interfering RNA (siRNA) designed for targeting human TF was transfected into SGC7901 cells. The expression levels of TF in the cells were detected by reverse transcription-polymerase chain reaction. Cell proliferation and chemosensitivity were measured by Cell Counting Kit-8. The metastatic potential of the SGC7901 cells was determined by Transwell experiments and wound-healing assays. Cell apoptosis was assessed by Annexin V-fluorescein isothiocyanate/propidium iodide double-staining method. The expression levels of TF mRNA were significantly reduced by the TF-siRNA in the SGC7901 cells, resulting in the suppression of cell proliferation, chemoresistance and invasion, and subsequently the induction of cell apoptosis. TF knockdown with siRNA inhibits the growth, invasion and chemoresistance and enhances the apoptosis of SGC7901 cells, providing a potential approach for gene therapy against human gastric cancer.

Effect of tissue factor on invasion inhibition and apoptosis inducing effect of oxaliplatin in human gastric cancer cell.

OBJECTIVE: Tissue factor (TF) is expressed abnormally in certain types of tumor cells, closely related to invasion and metastasis. The aim of this study was to construct a human gastric cancer cell line SGC7901 stably-transfected with human TF, and observe effects on oxaliplatin-dependent inhibition of invasion and the apoptosis induction. METHODS: The target gene TF was obtained from human placenta by nested PCR and introduced into the human gastric cell line SGC7901 through transfection mediated by lipofectamine. Stably-transfected cells were screened using G418. Examples successfully transfected with TF-pcDNA3 recombinant (experimental group), and empty vector pcDNA3 (control group) were incubated with oxaliplatin. Transwell chambers were used to show change in invasive ability. Caspase-3 activity was detected using a colorimetric method and annexin-V/PI double- staining was applied to detect apoptosis. RESULTS: We generated the human gastric cancer cell line SGC7901/TF successfully, expressing TF stably and efficiently. Compared with the control group, invasion increased, whereas caspase-3 activity and apoptosis rate were decreased in the experimental group. CONCLUSION: TF can enhance the invasive capacity of gastric cancer cells in vitro. Its increased expression may reduce invasion inhibition and apoptosis-inducing effects of oxaliplatin and therefore may warrant targeting for improved chemotherapy.