Exploration of natural product ingredients as inhibitors of human HMG-CoA reductase through structure-based virtual screening

An Update of Fungal Endophyte Diversity and Strategies for Augmenting Therapeutic Potential of their Potent Metabolites: Recent Advancement

Endophytic fungi represent a significant renewable resource for the discovery of pharmaceutically important compounds, offering substantial potential for new drug development. Their ability to address the growing issue of drug resistance has drawn attention from researchers seeking novel, nature-derived lead molecules that can be produced on a large scale to meet global demand. Recent advancements in genomics, metabolomics, bioinformatics, and improved cultivation techniques have significantly aided the identification and characterization of fungal endophytes and their metabolites. Current estimates suggest there are approximately 1.20 million fungal endophytes globally, yet only around 16% (190,000) have been identified and studied in detail. This underscores the vast untapped potential of fungal endophytes in pharmaceutical research. Research has increasingly focused on the transformation of bioactive compounds by fungal endophytes through chemical and enzymatic processes. A notable example is the anthraquinone derivative 6-O-methylalaternin, whose cytotoxic potential is enhanced by the addition of a hydroxyl group, sharing structural similarities with its parent compound macrosporin. These structure-bioactivity studies open up new avenues for developing safer and more effective therapeutic agents by synthesizing targeted derivatives. Despite the immense promise, challenges remain, particularly in the large-scale cultivation of fungal endophytes and in understanding the complexities of their biosynthetic pathways. Additionally, the genetic manipulation of endophytes for optimized metabolite production is still in its infancy. Future research should aim to overcome these limitations by focusing on more efficient cultivation methods and deeper exploration of fungal endophytes' genetic and metabolic capabilities to fully harness their therapeutic potential.

Virtual screening and evaluation of bioactive peptides from Haliotis discus hannai as potential HMGCR inhibitors for hyperlipidemia treatment

Introduction

Hyperlipidemia remains a major disease threatening global public health. The morbidity and mortality associated with cardiovascular diseases have been increasing. The inhibition of 3-Hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR), a key enzyme in the cholesterol synthesis pathway, can effectively reduce cholesterol levels.

Methods and results

In this study, the most suitable protease for preparing HMGCR inhibitory peptides was screened using the evaluation indexes of peptide yield and HMGCR inhibition rate. Peptide sequences with molecular weights <1 kDa were identified, and peptide fragments were docked with HMGCR for virtual screening. The inhibitory effects of these peptides on HMGCR activity were evaluated in vitro using a high-fat Hep-G2 cell model. The screened peptides possessed significant HMGCR inhibitory activity and reduced cholesterol micelle solubility and total cholesterol and triglyceride levels in hyperlipidemic Hep-G2 cells.

Conclusion

This study provides novel insights into developing natural drugs for hyperlipidemia; moreover, the results will facilitate the functional application of marine bioactive peptides.

Plant-Based Diets and Phytochemicals in the Management of Diabetes Mellitus and Prevention of Its Complications: A Review

Diabetes mellitus (DM) is currently regarded as a global public health crisis for which lifelong treatment with conventional drugs presents limitations in terms of side effects, accessibility, and cost. Type 2 diabetes (T2DM), usually associated with obesity, is characterized by elevated blood glucose levels, hyperlipidemia, chronic inflammation, impaired β-cell function, and insulin resistance. If left untreated or when poorly controlled, DM increases the risk of vascular complications such as hypertension, nephropathy, neuropathy, and retinopathy, which can be severely debilitating or life-threatening. Plant-based foods represent a promising natural approach for the management of T2DM due to the vast array of phytochemicals they contain. Numerous epidemiological studies have highlighted the importance of a diet rich in plant-based foods (vegetables, fruits, spices, and condiments) in the prevention and management of DM. Unlike conventional medications, such natural products are widely accessible, affordable, and generally free from adverse effects. Integrating plant-derived foods into the daily diet not only helps control the hyperglycemia observed in DM but also supports weight management in obese individuals and has broad health benefits. In this review, we provide an overview of the pathogenesis and current therapeutic management of DM, with a particular focus on the promising potential of plant-based foods.

In Silico Analysis of Selected Mikania Constituents As Human HMG-CoA Reductase, Human Inducible Nitric Oxide Synthase, and Human Squalene Synthase Inhibitory Agents

Background Numerous pharmacological activities have been reportedin Mikania species. In the present investigation, we aimed to evaluate 26 selected constituents of Mikania as potent inhibitory agents of human HMG-CoA reductase (hHMGR), human inducible nitric oxide synthase (hiNOS), and human squalene synthase (hSQS) using the in silico method. Methodology Twenty-six selected constituents of Mikania were investigated based on the docking behavior of three target enzymes, namely hHMGR, hiNOS, and hSQS, using the Cdocker method (Discovery Studio® 3.1, Accelrys, Inc., San Diego, CA). Results Docking analysis showed that methyl-3,5-di-O-caffeoyl quinate (MCQ) has the maximum binding energy (BE) (-39.63, -50.65, and -58.56 kcal/mol) with hHMGR, hiNOS, and hSQS enzymes. On the other hand, six ligands (kaurenoic acid (KAA), stigmasterol (SS), grandifloric acid (GA), kaurenol (KA), spathlenol (SP), and taraxerol (TA)) of Mikania failed to dock with either of the target enzymes (hHMGR, hiNOS, or hSQS). Conclusions The findings of the current study provide new insight regarding 26 selected ligands of Mikania as potent inhibitory agents of hHMGR, hiNOS, and hSQS.

Garcinia kola: a critical review on chemistry and pharmacology of an important West African medicinal plant

Garcinia kola Heckel (Clusiaceae) is a tree indigenous to West and Central Africa. All plant parts, but especially the seeds, are of value in local folklore medicine. Garcinia kola is used in treatment of numerous diseases, including gastric disorders, bronchial diseases, fever, malaria and is used to induce a stimulating and aphrodisiac effect. The plant is now attracting considerable interest as a possible source of pharmaceutically important drugs. Several different classes of compounds such as biflavonoids, benzophenones, benzofurans, benzopyran, vitamin E derivatives, xanthones, and phytosterols, have been isolated from G. kola, of which many appears to be found only in this species, such as garcinianin (found in seeds and roots), kolanone (fruit pulp, seeds, roots), gakolanone (stem bark), garcinoic acid, garcinal (both in seeds), garcifuran A and B, and garcipyran (all in roots). They showed a wide range of pharmacological activities (e.g. analgesic, anticancer, antidiabetic, anti-inflammatory, antimalarial, antimicrobial, hepatoprotective and neuroprotective effects), though this has only been confirmed in animal models. Kolaviron is the most studied compound and is perceived by many studies as the active principle of G. kola. However, its research is associated with significant flaws (e.g. too high doses tested, inappropriate positive control). Garcinol has been tested under better conditions and is perhaps showing more promising results and should attract deeper research interest (especially in the area of anticancer, antimicrobial, and neuroprotective activity). Human clinical trials and mechanism-of-action studies must be carried out to verify whether any of the compounds present in G. kola may be used as a lead in the drug development.

In Silico and In Vitro Analysis of Tacca Tubers (Tacca leontopetaloides) from Banyak Island, Aceh Singkil Regency, Indonesia, as Antihypercholesterolemia Agents

Tacca leontopetaloides (T. leontopetaloides) contain a number of active compounds such as flavonoids, tannins, phenolics, steroids, and alkaloids. The active compounds from plants have been shown to reduce the risk of cardiovascular disease by lowering cholesterol levels by inhibiting the enzyme 3-hydroxy-3-methylglutaryl-coenzym A (HMG-CoA) reductase activity. This study aims to investigate the potential active compounds in the ethanolic extract of Tacca tubers (T. leontopetaloides) from the Banyak Islands, Aceh Singkil Regency, Aceh Province both in vitro and in silico. Tacca tubers contain secondary metabolites including flavonoids, phenolics, tannins, steroids and saponins, according to phytochemical screening. In vitro investigation of ethanolic extract of Tacca tuber revealed inhibitory activity of HMG Co-A reductase with an IC₅₀ value of 4.92 ppm. Based on the in silico study, active compound from the extract, namely Stigmasterol with the highest binding affinities with HMG Co-A reductase (-7.2 kcal/mol). As a comparison, the inhibition of HMG Co-A reductase activity by simvastatin with an IC₅₀ 4.62 ppm and binding affinity -8.0 Kcal/mol. Our findings suggest that the ethanolic extract of Tacca tuber (T. leontopetaloides) from Banyak Islands, Aceh Province has the potential to inhibit the activity of HMG Co-A reductase.

Viral Hepatitis, Cholesterol Metabolism, and Cholesterol-Lowering Natural Compounds

Hepatitis is defined as inflammation of the liver; it can be acute or chronic. In chronic cases, the prolonged inflammation gradually damages the liver, resulting in liver fibrosis, cirrhosis, and sometimes liver failure or cancer. Hepatitis is often caused by viral infections. The most common causes of viral hepatitis are the five hepatitis viruses—hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). While HAV and HEV rarely (or do not) cause chronic hepatitis, a considerable proportion of acute hepatitis cases caused by HBV (sometimes co-infected with HDV) and HCV infections become chronic. Thus, many medical researchers have focused on the treatment of HBV and HCV. It has been documented that host lipid metabolism, particularly cholesterol metabolism, is required for the hepatitis viral infection and life cycle. Thus, manipulating host cholesterol metabolism-related genes and proteins is a strategy used in fighting the viral infections. Efforts have been made to evaluate the efficacy of cholesterol-lowering drugs, particularly 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, in the treatment of hepatitis viral infections; promising results have been obtained. This review provides information on the relationships between hepatitis viruses and host cholesterol metabolism/homeostasis, as well as the discovery/development of cholesterol-lowering natural phytochemicals that could potentially be applied in the treatment of viral hepatitis.

Potential dual inhibitors of PCSK-9 and HMG-R from natural sources in cardiovascular risk management

Atherosclerotic cardiovascular disease (ASCVD) stands amongst the leading causes of mortality worldwide and has attracted the attention of world's leading pharmaceutical companies in order to tackle such mortalities. The low-density lipoprotein-cholesterol (LDL-C) is considered the most prominent biomarker for the assessment of ASCVD risk. Distinct inhibitors of 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-R), the chief hepatic cholesterogenic enzyme, are being used since last seven decades to manage hypercholesterolemia. On the other hand, discovery and the association of proprotein convertase subtilisin/kexin type-9 (PCSK-9) with increased ASCVD risk have established PCSK-9 as a novel therapeutic target in cardiovascular medicine. PCSK-9 is well reckoned to facilitate the LDL-receptor (LDL-R) degradation and compromised LDL-C clearance leading to the arterial atherosclerotic plaque formation. The currently available HMG-R inhibitors (statins) and PCSK-9 inhibitors (siRNA, anti-sense oligonucleotides, and monoclonal antibodies) have shown great promises in achieving LDL-C lowering goals, however, their life long prescriptions have raised significant concerns. These deficits associated with the synthetic HMG-R and PCSK-9 inhibitors called for the discovery of alternative therapeutic candidates with potential dual HMG-R and PCSK-9 inhibitory activities from natural origins. Therefore, this report firstly describes the mechanistic insights into the cholesterol homeostasis through HMG-R, PCSK-9, and LDL-R functionality and then compiles the pharmacological effects of natural secondary metabolites with special emphasis on their dual HMG-R and PCSK-9 inhibitory action. In conclusion, various natural products exhibit atheroprotective effects via targeting HMG-R and PCSK-9 activities and lipoprotein metabolism, however, further clinical assessments are still warranted prior their approval for ASCVD risk management in hypercholesterolemic patients.

Hydroethanolic Extract of Prunus domestica L.: Metabolite Profiling and In Vitro Modulation of Molecular Mechanisms Associated to Cardiometabolic Diseases

High consumption of fruit and vegetables has an inverse association with cardiometabolic risk factors. This study aimed to chemically characterize the hydroethanolic extract of P. domestica subsp. syriaca fruit pulp and evaluate its inhibitory activity against metabolic enzymes and production of proinflammatory mediators. Ultra-high-performance liquid chromatography high-resolution mass spectrometry(UHPLC-HRMS) analysis showed the presence of hydroxycinnamic acids, flavanols, and glycoside flavonols, while nuclear magnetic resonance(NMR) analysis showed, among saccharides, an abundant presence of glucose. P. domestica fruit extract inhibited α-amylase, α-glucosidase, pancreatic lipase, and HMG CoA reductase enzyme activities, with IC50 values of 7.01 mg/mL, 6.4 mg/mL, 6.0 mg/mL, and 2.5 mg/mL, respectively. P. domestica fruit extract inhibited lipopolysaccharide-induced production of nitrite, interleukin-1 β and PGE2 in activated J774 macrophages. The findings of the present study indicate that P. domestica fruit extracts positively modulate in vitro a series of molecular mechanisms involved in the pathophysiology of cardiometabolic diseases. Further research is necessary to better characterize these properties and their potential application for human health.

Optimal Course of Statins for Patients With Aneurysmal Subarachnoid Hemorrhage: Is Longer Treatment Better? A Meta-Analysis of Randomized Controlled Trials

Statins are used in clinical practice to prevent from complications such as cerebral vasospasm (CVS) after aneurysmal subarachnoid hemorrhage (aSAH). However, the efficacy and safety of statins are still controversial due to insufficient evidence from randomized controlled trials and inconsistent results of the existing studies. This meta-analysis aimed to systematically review the latest evidence on the time window and complications of statins in aSAH. The randomized controlled trials in the databases of The Cochrane Library, PubMed, Web of Science, Embase, CNKI, and Wanfang from January 2005 to April 2021 were searched and analyzed systematically. Data analysis was performed using Stata version 16.0. The fixed-effects model (M-H method) with effect size risk ratio (RR) was used for subgroups with homogeneity, and the random-effects model (D-L method) with effect size odds ratio (OR) was used for subgroups with heterogeneity. The primary outcomes were poor neurological prognosis and all-cause mortality, and the secondary outcomes were cerebral vasospasm (CVS) and statin-related complications. This study was registered with PROSPERO (International Prospective Register of Systematic Reviews; CRD42021247376). Nine studies comprising 1,464 patients were included. The Jadad score of the patients was 5–7. Meta-analysis showed that poor neurological prognosis was reduced in patients who took oral statins for 14 days (RR, 0.73 [0.55–0.97]; I² = 0%). Surprisingly, the continuous use of statins for 21 days had no significant effect on neurological prognosis (RR, 1.04 [0.89–1.23]; I² = 17%). Statins reduced CVS (OR, 0.51 [0.36–0.71]; I² = 0%) but increased bacteremia (OR, 1.38 [1.01–1.89]; I² = 0%). In conclusion, a short treatment course of statins over 2 weeks may improve neurological prognosis. Statins were associated with reduced CVS. Based on the pathophysiological characteristics of CVS and the evaluation of prognosis, 2 weeks could be the optimal time window for statin treatment in aSAH, although bacteremia may increase.

Salvianolic Acid C Protects against Cisplatin-Induced Acute Kidney Injury through Attenuation of Inflammation, Oxidative Stress and Apoptotic Effects and Activation of the CaMKK-AMPK-Sirt1-Associated Signaling Pathway in Mouse Models

Acute kidney injury (AKI) is a sudden reduction in kidney activity and has a high mortality rate. Salvianolic acid C (SAC), one of the main polyphenolic components of Salvia miltiorrhiza, displays significant pharmacologically active effects. An animal model of cisplatin-induced kidney injury was used to study the potential of SAC to improve AKI. First, SAC was administered intraperitoneally in mice for 10 consecutive days, and then cisplatin was administered intraperitoneally on day 7 to establish a nephrotoxicity mouse model. SAC mitigated renal histological changes, blood creatinine (CRE) and blood urea nitrogen (BUN) production and the levels of inflammatory mediators in the cisplatin-induced AKI. Furthermore, malondialdehyde (MDA) levels were reduced and glutathione (GSH) was increased after intraperitoneal injection (i.p.) administration of SAC. In addition, based on Western blot data, SAC reduced the expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), nuclear factor kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) activation in mouse renal tissues. Finally, SAC diminished the level of TLR-4 expression and enhanced the production of several antioxidative enzymes (superoxidase dismutase (SOD1), glutathione peroxidase (GPx3), catalase, nuclear-factor-erythroid-2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1)), Sirtuin 1 (Sirt1), p-AMP-activated protein kinase (AMPK) and p-Ca²⁺/calmodulin-dependent protein kinase kinase (CaMKK). In addition, Sirt1 inhibition (EX 527) inverted the effect of SAC against cisplatin-induced nephrotoxicity. Collectively, SAC provides a therapeutic target with promising clinical potential after cisplatin treatment by attenuating oxidative stress and inflammation.

IAF, QGF, and QDF Peptides Exhibit Cholesterol-Lowering Activity through a Statin-like HMG-CoA Reductase Regulation Mechanism: In Silico and In Vitro Approach

In this study, in silico approaches are employed to investigate the binding mechanism of peptides derived from cowpea β-vignin and HMG-CoA reductase. With the obtained information, we designed synthetic peptides to evaluate their in vitro enzyme inhibitory activity. In vitro, the total protein extract and <3 kDa fraction, at 5000 µg, support this hypothesis (95% and 90% inhibition of HMG-CoA reductase, respectively). Ile-Ala-Phe, Gln-Gly-Phe, and Gln-Asp-Phe peptides were predicted to bind to the substrate binding site of HMGCR via HMG-CoAR. In silico, it was established that the mechanism of HMG-CoA reductase inhibition largely entailed mimicking the interactions of the decalin ring of simvastatin and via H-bonding; in vitro studies corroborated the predictions, whereby the HMG-CoA reductase activity was decreased by 69%, 77%, and 78%, respectively. Our results suggest that Ile-Ala-Phe, Gln-Gly-Phe, and Gln-Asp-Phe peptides derived from cowpea β-vignin have the potential to lower cholesterol synthesis through a statin-like regulation mechanism.

Improvements in HOMA indices and pancreatic endocrinal tissues in type 2-diabetic rats by DPP-4 inhibition and antioxidant potential of an ethanol fruit extract of Withania coagulans

CONTEXT

Withania coagulans (Stocks) Dunal fruits are used in the therapeutics of several ailments due to possessing of potent phytoconstituents which is also used traditionally for curing the diabetes.

OBJECTIVE

The present study was assessing the amelioration potential of the phytochemicals of an ethanol fruit extract of W. coagulans (Stocks) Dunal in the HOMA (Homeostatic model assessment) indices and pancreatic endocrinal tissues by inhibition of DPP-4 and antioxidants activities.

MATERIAL AND METHODS

The identification of phytoconstituents of the test extract was performed by LCMS. Further, assessments of in-vitro, in-vivo and in-silico were achieved by following standard methods. In-vivo studies were conducted on type-2 diabetic rats.

RESULTS

The chosen extract inhibited DPP-4 activity by 63.2% in an in vitro assay as well as significantly inhibit serum DPP-4 levels. Accordingly, the administration of the ethanol fruit extract resulted in a significant (P ≤ 0.001) alterations in the lipid profile, antioxidant levels, and HOMA indices. Moreover, pancreatic endocrinal tissues (islet of Langerhans) appeared to have the restoration of normal histoarchitecture as evidenced by increased cellular mass. Molecular docking (Protein-ligands) of identified phytoconstituents with DPP-4 (target enzyme) shown incredibly low binding energy (Kcal/mol) as required for ideal interactions. ADMET analysis of the pharmacokinetics of the identified phytoconstituents indicated an ideal profile as per Lipinski laws.

CONCLUSION

It can be concluded that the phytoconstituents of an ethanol fruit extract of W. coagulans have the potential to inhibit DPP-4 which result in improved glucose homeostasis and restoration of pancreatic endocrinal tissues in type-2 diabetic rats.

Salvianolic Acid C against Acetaminophen-Induced Acute Liver Injury by Attenuating Inflammation, Oxidative Stress, and Apoptosis through Inhibition of the Keap1/Nrf2/HO-1 Signaling

Acetaminophen (APAP) overdose is one of the most common causes of drug-induced acute liver failure in humans. To investigate the hepatoprotective effect of salvianolic acid C (SAC) on APAP-induced hepatic damage, SAC was administered by daily intraperitoneal (i.p.) injection for 6 days before the APAP administration in mice. SAC prevented the elevation of serum biochemical parameters and lipid profile including aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (T-Bil), total cholesterol (TC), and triacylglycerol (TG) against acute liver failure. Additionally, SAC reduced the content of malondialdehyde (MDA), the cytochrome P450 2E1 (CYP2E1), and the histopathological alterations and inhibited the production of proinflammatory cytokines in APAP-induced hepatotoxicity. Importantly, SAC effectively diminished APAP-induced liver injury by inhibiting nuclear factor-kappa B (NF-κB), toll-like receptor 4 (TLR4), and mitogen-activated protein kinases (MAPKs) activation signaling pathway. Moreover, SAC enhanced the levels of hepatic activities of glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, and Kelch-like ECH-associated protein 1 (Keap1)/erythroid 2–related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway in APAP-induced mice. SAC mainly inhibited the activation of apoptotic pathways by reduction of cytochrome c, Bax, and caspase-3 protein expression. Taken together, we provide the molecular evidence that SAC protected the hepatocytes from APAP-induced damage by mitigating mitochondrial oxidative stress, inflammatory response, and caspase-mediated antiapoptotic effect through inhibition of the Keap1/Nrf2/HO-1 signaling axis.

Influence of extraction methods of bay leaves (Syzygium polyanthum) on antioxidant and HMG-CoA Reductase inhibitory activity

Objective

Bay leaf, one of the plants in Indonesia that has been shown to have activities to reduce cholesterol in the blood. HMG-CoA Reductase inhibition is one of many mechanisms in lowering the level of cholesterol in the blood. Here, we reported the inhibitory activity of HMG-CoA Reductase of bay leaves ethanol extracts that we suspected to be the mechanism of action of bay leaves in reducing cholesterol in the blood. In this research we also investigated the correlation between the inhibitory activities, the total phenol content and antioxidant activities of bay leaves (Syzygium polianthum) ethanol extracts.

Methods

The inhibitory activity of HMG-CoA Reductase was determined kinetically at 340 nm using simvastatin as positive control. In vitro scavenging assays of 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric ion reducing antioxidant power (FRAP), and beta-carotene method were used to determine the antioxidant activities. The total phenolic content was determined by Folin-Ciocalteu's method.

Results

The IC₅₀ of bay leaves ethanolic extract obtained by percolation and soxhlet extraction method towards HMG-CoA Reductase enzyme activity were 49.50 ± 0.700 μg/mL and 15.50 ± 0.707 μg/mL, respectively, while the IC₅₀ of simvastatin was 0.00238 ± 0.00004 μg/mL. The antioxidant activity and total phenolic content of bay leaves ethanolic extract obtained by Soxhlet extraction method was higher compared to the percolation method (DPPH and beta-carotene assay results). The 3D linear analysis showed that there was a high correlation between the inhibition activities of HMG-CoA Reductase pattern of both extract types and the total phenol pattern and also the antioxidant pattern of these extracts.

Conclusion

The result showed that the bay leaves ethanolic extract have a potent activity to reduce the cholesterol serum level by inhibition of HMG-CoA Reductase activity. The activity was due to the phenolic compounds in the extracts as well as the antioxidant activity of the extracts.