Potential Lipase Inhibitors Research Articles

Alisol C 23-acetate might be a lead compound of potential lipase inhibitor from Alismatis Rhizoma: Screening, identification and molecular dynamics simulation

Alismatis Rhizoma (AR), a traditional Chinese medicine for treating obesity in traditional Chinese medicine clinic, is recognized as a promising source of lead compounds of lipase inhibitors. Ultrafiltration centrifugal combined with liquid chromatography-mass spectrometry (UF-LC-MS) was used for screening potential lipase inhibitors from AR, and the result indicated the binding capacity between compound 7 and lipase (92.3 ± 1.28 %) was significantly higher than other triterpenoids, and was identified as alisol C 23-acetate. It exhibited a mixed-type inhibitory behavior with an IC50 value of 84.88 ± 1.03 μM. Subsequently, the binding pockets of alisol C 23-acetate to lipase were predicted, and their binding mechanism was explored with molecular simulation. Pocket 1 (active center) and pocket 4 might be the orthosteric and allosteric binding sites of alisol C 23-acetate to lipase, respectively. The interaction between alisol C 23-acetate and lipase was identified to involve key amino acid residues such as GLY-77, PHE-78, TYR-115, LEU-154, PRO-181, PHE-216, LEU-264, ASP-278, GLN-306, ARG-313, and VAL-426. Meanwhile, alisol C 23-acetate remained stable during the intestinal digestive but degraded in the gastric digestion. Overall, alisol C 23-acetate is expected to be the lead compound of lipase inhibitors for treating obesity.

Enzymatic characteristics and potential natural inhibitors of oat lipase

Lipase plays a pivotal role in the rancidity pathway of lipids and it hinders the industrial development of oat products. The existing methods to inactivate lipase are energy intensive and cause nutrient loss. Understanding the structure and characteristics of oat lipase could lead to better inactivation methods. Oat Lipase was extracted, partially purified, and its characteristics and structure were studied. The partially purified protein matched the Os06g0157000 protein with 36.5 kDa and belonged to the ‘GDSL’ lipolytic enzyme family. Oat lipase showed highest catalytic activity at 40 °C, pH 7.5 and held stability below 50 °C and at pH 7.0–8.0. Cu2+, Fe3+, Ba2+, K+ and Mg2+ all inhibited oat lipase activity, with Fe3+ having the strongest effect. The oat lipase showed high specificity for hydrolysis of oat oil. The results of molecular docking and molecular dynamics analysis showed that avenanthramides (AVAS), rutin, and ferulic acid were potential lipase inhibitors, with ferulic acid having the greatest effect. In storage experiments of pearled oats, ferulic acid delayed lipid hydrolysis and lipid oxidation degradation. In the present study, we found a natural lipase inhibition that is safe and nutritional.

A Simple and Portable Personal Glucose Meter Method Combined with Molecular Docking for Screening of Lipase Inhibitors.

With the increase of obesity incidence, the development of antiobesity drugs has aroused extensive interest. In this study, a simple and portable personal glucose meter (PGM) method based on the lipase-mediated reaction combined with molecular docking was developed for the screening of lipase inhibitors. Lipase can catalyse the hydrolysis of 4-acetamidophenyl acetate to form acetaminophen, which can directly trigger the reduction of K3[Fe(CN)6] to K4[Fe(CN)6] in the glucose test strips and generate an electrical signal that can be detected by the PGM. When lipase inhibitors exist, the yield of acetaminophen will be reduced and results in a corresponding decrease of the PGM signal. Therefore, the activity of lipase can be measured by the PGM. After optimization of the experimental conditions, the inhibitory activity of fourteen small-molecule compounds and fifteen natural product extracts on lipase were evaluated by the developed PGM method. The results indicate that tannic acid, (-)-epigallocatechin gallate, (-)-epigallocatechin, (-)-epicatechin gallate, and epicatechin have good inhibitory effect on lipase (% of inhibition higher than 40.0%). Besides, the natural product extracts of Galla Chinensis, lemon, and Rhei Radix et Rhizoma have a good inhibitory effect on lipase with % of inhibition of (97.5 ± 0.6)%, (88.1 ± 0.7)%, and (79.1 ± 1.6)%, respectively. Finally, the binding sites and modes of six small-molecule compounds on lipase were investigated by the molecular docking study. The results show that the developed PGM method is an effective approach for the discovery of potential lipase inhibitors.

Rapid Screening of Lipase Inhibitors from Ophiopogonis Radix Using High-Performance Thin Layer Chromatography by Two Step Gradient Elution Combined with Bioautographic Method.

In this study, a high-performance thin layer chromatography (HPTLC) method by two step gradient elution with two mobile phases was developed for the simultaneous analysis of seven constituents in Ophiopogonis Radix. The chromatography was performed on silica gel 60 F254 plate with dichloromethane-methanol-ethyl acetate-water (70:25:12:3, v/v/v/v) and dichloromethane-methanol (300:1, v/v) as the mobile phase for two step gradient elution. Then, the HPTLC profiles were observed after derivatization with 10% sulfuric acid in ethanol solution. The obtained HPTLC images were further analyzed by chemometric approaches and the samples could be clustered based on regions and/or growth years, which were two important factors affecting the constituents in Ophiopogonis Radix. Furthermore, five compounds including ophiopogonin D, ophiopojaponin C, ophiopogonin D’, ophiopogonin C’ and methylophiopogonanone B were screened as potential lipase inhibitors from Ophiopogonis Radix by the HPTLC-bioautographic method. The binding modes and interactions between the five compounds and lipase were further explored by molecular docking analysis. The developed HPTLC method could be used for quality control of Ophiopogonis Radix and screening of the potential lipase inhibitors.

Screening of Anti-Lipase Components of Artemisia argyi Leaves Based on Spectrum-Effect Relationships and HPLC-MS/MS

Pancreatic lipase is a key lipase for triacylglyceride digestion and absorption, which is recognized as a promising target for treatment of metabolic disorders. Natural phytochemicals are hopeful sources for pancreatic lipase inhibitors. The leaves of Artemisia argyi H.Lév. and Vaniot (AL) is commonly used as herbal medicine or food supplement in China and other Asian countries for hundreds of years. AL mainly contains essential oils, phenolic acids, flavonoids and terpenoids, which exhibit many pharmacological activities such as antioxidant, anti-inflammatory, antimicrobial, analgetic, anti-cancer, anti-diabetes and immunomodulatory effects. However, the anti-lipase activity of AL was lack of study and the investigation of anti-lipase ingredients from AL was also insufficient. In the present study, the anti-lipase activity of AL was evaluated in vitro and the potentially pancreatic lipase inhibitors of AL were investigated. High performance liquid chromatography was used to establish fingerprints of AL samples, and fifteen peaks were selected. The anti-lipase activities of AL samples were evaluated by a pancreatic lipase inhibition assay. Then, the spectrum-effect relationships between fingerprints and pancreatic lipase inhibitory activities were investigated to identify the anti-lipase constitutes in AL. As the results, four caffeoylquinic acids, which were identified as neochlorogenic acid, chlorogenic acid, isochlorogenic acid B, and isochlorogenic acid A by high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry, were selected as potential pancreatic lipase inhibitors in AL. Moreover, anti-lipase activity assessment and molecular docking study of the four compounds were performed to validate the potential lipase inhibitors in AL. The results revealed that the four caffeoylquinic acids in AL as bioactive compounds displayed with anti-lipase activity. The present research provided evidences for the anti-lipase activity of AL, and suggested that some bioactive compounds in AL could be used as lead compounds for discovering of new pancreatic lipase inhibitors.

The herbicide quinclorac as potent lipase inhibitor: Discovery via virtual screening and in vitro/in vivo validation.

Lipolysis is primarily controlled by the stepwise action of hormone-sensitive lipase (HSL) and monoglyceride lipase (MGL) to release free fatty acids and glycerol. A high level of circulating free fatty acids is well-known to mediate insulin resistance. Thus, the need to discover lipase inhibitors against both enzyme systems remains urgent. Agrochemicals are tightly regulated chemicals and therefore are potential source of new medicinal agents. Accordingly, we implemented a computational workflow to search for new lipase inhibitory leads by virtually screening commercial agrochemicals against HSL and MGL employing binding pharmacophores and docking experiments. Ten agrochemicals were identified as potential lipase inhibitors, out of which quinclorac, a safe herbicide, achieved high-ranking score. Subsequent in vitro evaluation against rat epididymal lipase activity showed quinclorac to exhibit nanomolar anti-lipase IC50 . Subsequent in vivo testing showed quinclorac to significantly decrease blood glycerol levels after acute exposure (150mg/kg) and multiple dosing (50 or 25mg/kg) (p<0.05).

Monte Carlo method based QSAR modelling of natural lipase inhibitors using hybrid optimal descriptors

Obesity is one of the most provoking health burdens in the developed countries. One of the strategies to prevent obesity is the inhibition of pancreatic lipase enzyme. The aim of this study was to build QSAR models for natural lipase inhibitors by using the Monte Carlo method. The molecular structures were represented by the simplified molecular input line entry system (SMILES) notation and molecular graphs. Three sets – training, calibration and test set of three splits – were examined and validated. Statistical quality of all the described models was very good. The best QSAR model showed the following statistical parameters: r2 = 0.864 and Q2 = 0.836 for the test set and r2 = 0.824 and Q2 = 0.819 for the validation set. Structural attributes for increasing and decreasing the activity (expressed as pIC50) were also defined. Using defined structural attributes, the design of new potential lipase inhibitors is also presented. Additionally, a molecular docking study was performed for the determination of binding modes of designed molecules.

Screening of lipase inhibitors in Folium Mori with lipase-linked magnetic microspheres by high-performance liquid chromatography and evaluation in diabetic mice.

A new method for the screening of compounds with hypoglycemic effect from traditional Chinese medicines employing high-performance liquid chromatography and lipase-linked magnetic microspheres has been proposed. We hypothesized that the interaction of traditional Chinese medicine extracts with lipase-linked magnetic microspheres should decrease the concentration of compounds with hypoglycemic effect. Using this approach, the potential lipase inhibitors in Folium Mori extract were investigated. First, lipase was immobilized on magnetic microspheres by a chemical method. Then, by comparing the chromatograms of samples before and after the interaction with lipase-linked magnetic microspheres, seven compounds of Folium Mori extract were identified. It was found that protocatechuic acid, chlorogenic acid, protocatechualdehyde, rutin, isoquercitrin, astragalin, and dicaffeoylquinic acid B had evident combination with lipase-linked magnetic microspheres. Their hypoglycemic effects were verified in streptozocin-induced diabetic mice. In the present study, astragalin was verified to improve the glucose tolerance and lower the level of glucose in streptozocin-induced diabetic mice, which indicated that astragalin might be a new highly efficient lipase inhibitor. Based on these significant results, this method could be a convenient approach to screen potential lipase inhibitors from traditional Chinese medicines. Meanwhile, it also could be expanded to screen other active compounds in traditional Chinese medicines.

Potential lipase inhibitors from Chinese medicinal herbs

Context: Obesity has become a major health concern, and it places both personal and economic burdens on the world’s population. Traditional Chinese medicinal herbs are rich source of lead compounds and are possible drug candidates, which may be used to treat this condition.Objective: This study screened potent pancreatic lipase inhibitors found in traditional Chinese medicinal herbs for ability to treat obesity.Materials and methods: A porcine pancreatic lipase inhibition assay was established, and the inhibitory activity of 35 traditional Chinese medicinal herbs was evaluated at a concentration of 200 μg/mL. Two elutions of herbal extracts with strong lipase inhibitory activity were further fractionated by preparative high-performance liquid chromatography into 22 sub-fractions each, and these sub-fractions were tested for anti-lipase activity. Sub-fractions, which exhibited strong lipase inhibitory activity, were continuously fractionated into individual compounds. Two active compounds with potent anti-lipase activity were finally isolated and identified from two traditional Chinese medicinal herbs, respectively.Results: Among 35 traditional Chinese medicinal herbs, the 95% ethanol elutions of Panax notoginseng (Burk.) F.H. Chen (Araliaceae) and Magnolia officinalis Rehd. et Wils (Magnoliaceae) showed strong anti-lipase activity. Two compounds, including 20(S)-ginsenoside Rg3 and honokiol were identified using bioactivity-guided isolation with IC50 = 33.7 and 59.4 μg/mL, respectively.Conclusion: 20(S)-ginsenoside Rg3 and honokiol might be suitable candidates for the treatment of obesity.

A Bioactivity-Based Method for Screening, Identification of Lipase Inhibitors, and Clarifying the Effects of Processing Time on Lipase Inhibitory Activity of Polygonum Multiflorum.

Traditional Chinese medicine (TCM) has been used for the treatment of many complex diseases. However, the bioactive components are always undefined. In this study, a bioactivity-based method was developed and validated to screen lipase inhibitors and evaluate the effects of processing on the lipase inhibitory activity of TCM by ultrahigh performance liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry and fraction collector (UHPLC/Q-TOF-MS-FC). The results showed that both Polygonum multiflorum and processed P. multiflorum extracts had inhibitory effect against lipase with IC50 values of 38.84 μg/mL and 190.6 μg/mL, respectively. Stilbenes, phenolic acid, flavonoids, and anthraquinones were considered to be the potential lipase inhibitors. Eleven potential lipase inhibitors were simultaneously determined by UHPLC. Principal component analysis (PCA) was employed in exploring the effects of processing time on lipase inhibitory activity of P. multiflorum. Compared with conventional methods, a bioactivity-based method could quantitatively analyze lipase inhibitory activity of individual constituent and provide the total lipase inhibitory activity of the samples. The results demonstrated that the activity integrated UHPLC/Q-TOF-MS-FC method was an effective and powerful tool for screening and identifying lipase inhibitors from traditional Chinese medicines.

A new TLC bioautographic assay for qualitative and quantitative estimation of lipase inhibitors.

Lipase inhibitory assays based on TLC bioautography have made recent progress; however, an assay with greater substrate specificity and quantitative capabilities would advance the efficacy of this particular bioassay. To address these limitations, a new TLC bioautographic assay for detecting lipase inhibitors was developed and validated in this study. The new TLC bioautographic assay was based on reaction of lipase with β-naphthyl myristate and the subsequent formation of the purple dye between β-naphthol and Fast Blue B salt (FBB). The relative lipase inhibitory capacity (RLIC) was determined by a TLC densitometry with fluorescence detection, expressed as orlistat equivalents in millimoles on a per sample weight basis. Six pure compounds and three natural extracts were evaluated for their potential lipase inhibitory activities by this TLC bioautographic assay. The β-naphthyl myristate as the substrate improved the detection sensitivity and specificity significantly. The limit of detection (LOD) of this assay was 0.01 ng for orlistat, the current treatment for obesity. This assay has acceptable accuracy (92.07-105.39%), intra-day and inter-day precisions [relative standard deviation (RSD), 2.64-4.40%], as well as intra-plate and inter-plate precisions (RSD, 1.8-4.9%). The developed method is rapid, simple, stable, and specific for screening and estimation of the potential lipase inhibitors.