Inhibition of glycosidase by ursolic acid: in vitro, in vivo and in silico study

Fabrication and characterization of responsible approach for targeted intestinal releasing and enhancing the effectivity of kidney tea saponin upon porous starch /xanthan gum /sodium alginate-based hydrogel bead

To enhance the intestinal targeted release of kidney tea saponins, a simple delivery system was designed through the use of porous starch (PS), sodium alginate (ALG) and xanthan gum (XG). Porous starch was prepared by hydrolysis with a combination of α-amylase and amyloglucosidase and it was characterized by scanning electron microscopy, which revealed the formation of porous structures in the starch granules. The results of one-way optimisation illustrated that this unique delivery system achieved 79.00 ± 1.22 % of the optimal encapsulation rate. The carrier structure was subjected to analysis using Fourier transform infrared spectroscopy and X-ray diffraction. The α-glucosidase inhibition assay showed better inhibition of kidney tea saponin compared to the positive control acarbose. In addition, the effectiveness of this delivery design was confirmed via an in vitro simulated digestion method. It was showed that only a 15.57 ± 1.27 % release rate of kidney tea saponin was observed in the upper gastrointestinal tract, whereas release rates of 17.51 ± 1.29 % and 41.07 ± 0.76 % were observed for xanthan gum/sodium alginate/kidney tea saponin and sodium alginate/kidney tea saponin beads, respectively. It was concluded that the utilization of PS and a xanthan gum/sodium alginate coating represents an efficacious methodology for the development of an intestinal targeted delivery system.

Chemo-profiling and exploring therapeutic potential of Momordica dioica Roxb. ex Willd. for managing metabolic related disorders: In-vitro studies, and docking based approach

ETHNOPHARMACOLOGICAL RELEVANCE

Momordica dioica Roxb. ex Willd. (M. dioica Roxb.) a nutritious and therapeutic property rich crop of Cucurbitaceae plant family. In various folklore medicine including Ayurveda fruits are used to treat several metabolic related disorders i.e., hyperglycemia, hyperlipidemia, diabetes, obesity etc. Furthermore, traditionally it is used to treat fever, inflammation, ulcer, skin diseases, haemorrhoids, hypertension and also employed as cardioprotective, hepatoprotective, analgesic, diuretic.

AIM OF THE STUDY

This study focuses to explore the therapeutic potential of Momordica dioica Roxb. ex Willd. through in-vitro and in-silico approach for managing hyperlipidemia, hyperglycemia and related metabolic disorders along with its phytochemical profiling for quality evaluation and validation of traditional claim.

MATERIALS AND METHODS

The present study was carried out on hydroalcohol extract of dried leaf and fruit of Momordica dioica. In-vitro antioxidant potential using DPPH and Nitric oxide scavenging assay along with in-vitro enzyme inhibitory potential against α-amylase, α-glucosidase, and pancreatic lipase enzymes was studied. The bioactive metabolites were identified from the most potent bioactive extract by analysis with LC-QTOF-MS and also studied their role to lessen the metabolic related disorder through in-silico approaches.

RESULTS

The results confirmed that the fruit extract is more active to possess antioxidant and prominent enzyme inhibition potential compared to the leaf. Sixteen identified metabolites in M. dioica Roxb. fruits may be responsible for the therapeutic potential related to metabolic related disorder. The in-silico study of the identified phytomolecules against α-amylase, α-glucosidase and pancreatic lipase showed significant docking scores ranging from -9.8 to -5.5, -8.3 to -4.8 and -8.3 to -6 respectively.

CONCLUSION

The current study illustrated that M. dioica Roxb., a traditionally important plant is potential against metabolic related disorders. Phytocomponents present in the fruit extract may be responsible for antioxidant as well as the enzymes' inhibitory potential. Thus, fruits of M. dioica Roxb. will be useful as alternative therapeutics for treatment of hyperlipidemia, hyperglycemia and related metabolic disorders.

Potential Pharmacological Properties of Triterpene Derivatives of Ursolic Acid

Ursolic acid (UA) and its derivatives have garnered significant attention due to their extensive pharmacological activity. UA is a pentacyclic triterpenoid found in a variety of plants, such as apples, rosemary, thyme, etc., and it possesses a range of pharmacological properties. Researchers have synthesized various derivatives of UA through structural modifications to enhance its potential pharmacological properties. Various in vitro and in vivo studies have indicated that UA and its derivatives possess diverse biological activities, such as anticancer, antifungal, antidiabetic, antioxidant, antibacterial, anti-inflammatory and antiviral properties. This review article provides a review of the biological activities of UA and its derivatives to show their valuable therapeutic properties useful in the treatment of different diseases, mainly focusing on the relevant structure-activity relationships (SARs), the underlying molecular targets/pathways, and modes of action.

Triterpenoids-templated self-assembly nanosystem for biomimetic delivery of CRISPR/Cas9 based on the synergy of TLR-2 and ICB to enhance HCC immunotherapy

Combination immunotherapy has shown promising potential for enhancing the objective response rate compared to immune checkpoint blockade (ICB) monotherapy. However, combination therapy with multi-drugs is limited by the different properties of the agents and inconsistent synergistic targeted delivery. Herein, based on a universal triterpene template and the anticancer active agent ursolic acid (UA), a cytomembrane-coated biomimetic delivery nanoplatform (UR@M) prepared by the self-assembly of a PD-L1 targeted CRISPR/Cas9 system and UA was designed for hepatocellular carcinoma (HCC) treatment. UR@M showed enhanced tumor accumulation in vivo with homologous tumor targeting, and CRISPR in the nanosystem exhibited potent gene-editing efficiency of 76.53% in vitro and 62.42% in vivo with no off-target effects. UA activated the natural immune system through the TLR-2-MyD88-TRAF6 pathway, which synergistically enhanced the proliferation of natural killer cells and dendritic cells and realized excellent immune cytotoxic T cell infiltration by combining with the ICB of PD-L1. The strategy of work along both lines based on innate immune and adaptive immunity displayed a significant effect in tumor regression. Overall, the UA-templated strategy "killed three birds with one stone" by establishing a self-assembly nanosystem, inducing tumor cell death, and promoting synergistic immunostimulation for HCC treatment.

Determination of antioxidant, DNA protection, enzyme inhibition potential and molecular docking studies of a biomarker ursolic acid in Nepeta species

Ursolic acid (UA), which has many biological properties such as anti-cancer, anti-inflammatory and antioxidant, and regulates some pharmacological processes, has been isolated from the flowers, leaves, berries and fruits of many plant species. In this work, UA was purified from the methanol-chloroform crude extract of Nepeta species (N. aristata, N. baytopii, N. italica, N. trachonitica, N. stenantha) using a silica gel column with chloroform or ethyl acetate solvents via bioactivity-guided isolation. The most active sub-fractions were determined under bioactivities using antioxidant and DNA protection activities and enzyme inhibitions. UA was purified from these fractions and its structure was elucidated by NMR spectroscopy techniques. The highest amount of UA was found in N. stenantha (8.53 mg UA/g), while the lowest amount of UA was found in N. trachonitica (1.92 mg UA/g). The bioactivities of UA were evaluated with antioxidant and DNA protection activities, enzyme inhibitions, kinetics and interactions. The inhibition values (IC50) of α-amylase, α-glucosidase, urease, CA, tyrosinase, lipase, AChE, and BChE were determined between 5.08 and 181.96 µM. In contrast, Ki values of enzyme inhibition kinetics were observed between 0.04 and 0.20 mM. In addition, Ki values of these enzymes for enzyme-UA interactions were calculated as 0.38, 0.86, 0.45, 1.01, 0.23, 0.41, 0.01 and 2.24 µM, respectively. It is supported that UA can be widely used as a good antioxidant against oxidative damage, an effective DNA protector against genetic diseases, and a suitable inhibitor for metabolizing enzymes.Communicated by Ramaswamy H. Sarma.

The Analysis of Leontopodium leontopodioides (Willd.) Beauv. Chemical Composition by GC/MS and UPLC-Q-Orbitrap MS

Leontopodium leontopodioides (Willd.) Beauv. (L. leontopodioides.) has been used to treat lung diseases in traditional Chinese medicine (TCM). However, a systematic analysis of its chemical components has not been reported so far. In this study, UPLC-Q-Orbitrap MS and GC-MS were applied to investigate the chemical composition of the water extracts and essential oils of L. leontopodioides. UPLC-Q-Orbitrap MS adopts a heating electrospray ionization source, collecting primary and secondary mass spectrometry data in positive and negative ions, respectively, and uses Compound Discoverer 3.2 software to analyze the collected raw data. As a result, a total of 39 compounds were identified from their high-resolution mass spectra in both positive and negative ionization modes, including 13 flavonoids and their glycosides, 15 phenolic acids, 4 oligosaccharides and glycosides, 4 pentacyclic triterpenoids, and 3 other compounds. Among them, 18 chemical components have not been reported in L. leontopodioides. In the GC-MS section, two common organic solvents (n-hexane and diethyl ether) were used to extract essential oils, and the mass spectra were recorded at 70 eV (electron impact) and scanned in the range of 35∼450 m/z. Compounds were identified using NIST (version 2017), and the peak area normalization method was used to calculate their relative amounts. Finally, 17 components were identified in the volatile oil extracted with n-hexane, accounting for 80.38% of the total volatile oil, including monoterpenoids, phenylpropene, fatty acids, and aliphatic hydrocarbons. In the volatile oil extracted with diethyl ether, 16 components were identified, accounting for 73.50% of the total volatile oil, including phenylpropene, aliphatic hydrocarbons, monoterpenoids, fatty acids, and esters. This study was the first to conduct a comprehensive analysis of the chemical composition of the L. leontopodioides water extract and its essential oil, and a comprehensive chemical composition spectrum was constructed, to lay a foundation for its further pharmacodynamic material basis and quality evaluation.

In vitro and in silico docking and molecular dynamic of antimicrobial activities, alpha-glucosidase, and anti-inflammatory activity of compounds from the aerial parts of Mussaenda saigonensis

Twelve compounds were isolated from Mussaenda saigonensis aerial parts through phytochemical analysis and the genus Mussaenda is the first place where the compounds 4-6 and 11-12 have been found. Based on the ability to inhibit NO production in RAW264.7 cells, compound 2 has demonstrated the strongest anti-inflammatory activity in vitro with an IC50 of 7.6 μM, as opposed to L-NMMA's IC50 of 41.3 μM. Compound 12 was found to be the most effective inhibitor of alpha-glucosidase enzyme in vitro, with an IC50 value of 42.4 μM (compared to 168 μM for acarbose). Compounds 1-12 were evaluated in vitro for antimicrobial activity using the paper dish method. Compound 11 demonstrated strong antifungal activity against M. gypseum with a MIC value of 50 μM. In silico docking for antimicrobial activity, pose 90 or compound 11 docked well to the 2VF5 enzyme, PDB, which explains why compound 11 had the highest activity in vitro. Entry 2/pose 280 demonstrated excellent anti-inflammatory activity in silico. The stability of the complex between pose 280 and the 4WCU enzyme for anti-inflammatory activity has been assessed using molecular dynamics over a simulation course ranging from 0 to 100 ns. It has been found to be stable from 60 and 100 ns. The Tyr 159 (95%, H-bond via water bridge), Asp 318 (200%, multiple contacts), Met 273 (75%, hydrophobic interaction via water bridge), and Gln 369 (75%, H-bond via water bridge) interacted well within the time range of 0 to 100 ns. It has more hydrophilic or polar pharmacokinetics.

Mechanistic study on the inhibition of α-amylase and α-glucosidase using the extract of ultrasound-treated coffee leaves

BACKGROUND

Our previous studies have shown that ultrasound-treated γ-aminobutyric acid (GABA)-rich coffee leaves have higher angiotensin-I-converting enzyme inhibitory activity than their untreated counterpart. However, whether they have antidiabetic activity remains unknown. In this study, we aimed to investigate the inhibitory activities of coffee leaf extracts (CLEs) prepared with ultrasound (CLE-U) or without ultrasound (CLE-NU) pretreatment on α-amylase and α-glucosidase. Subsequently, we evaluated the binding interaction between CLE-U and both enzymes using multi-spectroscopic and in silico analyses.

RESULTS

Ultrasound pretreatment increased the inhibitory activities of CLE-U against α-amylase and α-glucosidase by 21.78% and 25.13%, respectively. CLE-U reversibly inhibits both enzymes, with competitive inhibition observed for α-amylase and non-competitive inhibition for α-glucosidase. The static quenching of CLE-U against both enzymes was primarily driven by hydrogen bond and van der Waals interactions. The α-helices of α-amylase and α-glucosidase were increased by 1.8% and 21.3%, respectively. Molecular docking results showed that the key differential compounds, including mangiferin, 5-caffeoylquinic acid, rutin, trigonelline, GABA, caffeine, glutamate, and others, present in coffee leaves interacted with specific amino acid residues located at the active site of α-amylase (ASP197, GLU233, and ASP300). The binding of α-glucosidase and these bioactive components involved amino acid residues, such as PHE1289, PRO1329, and GLU1397, located outside the active site.

CONCLUSION

Ultrasound-treated coffee leaves are potential anti-diabetic substances, capable of preventing diabetes by inhibiting the activities of α-amylase and α-glucosidase, thus delaying starch digestion. Our study provides valuable information to elucidate the possible antidiabetic capacity of coffee leaves through the inhibition of α-amylase and α-glucosidase activities. © 2023 Society of Chemical Industry.

Inhibitory Potential of Different Bilberry (Vaccinium myrtillus L.) Extracts on Human Salivary α-Amylase

Recently, consumer preferences for bilberries have increased markedly. This fact is probably related to their natural constituents, such as phenolic compounds including anthocyanins and tannins, as well as the vitamins and minerals they contain. Phenolic compounds are known for their numerous beneficial effects on human health. Moreover, bilberry fruits have been shown to inhibit the activity of carbohydrate hydrolyzing enzymes, which can significantly decrease the postprandial increase in blood glucose levels. Thus, the aim of the present study is to investigate the inhibitory effect of Vaccinium myrtillus L. extracts on key enzyme α-amylase, linked to type 2 diabetes. No data have been published on the inhibitory properties of Vaccinium myrtillus L. fruits growing wild in Bulgaria against carbohydrate enzymes. Bilberry extracts were analyzed for total polyphenols, total anthocyanin content, antioxidant activity and their inhibitory properties against α-amylase. The contents of flavonols, anthocyanins and stilbenes were determined by HPLC analysis. The identified flavonols in the analyzed bilberry extracts were mainly represented by quercetin derivatives as rutinoside. The predominant anthocyanins for both aqueous and organic solvents were delphinidin-3-galactoside and malvidin-3-glucoside. The results revealed that bilberry extracts are effective inhibitors of α-amylase, with IC50 values from 20.8 to 194.8 μg GAE/mL. All the samples proved to have antioxidant activity measured by three different in vitro assays (FRAP, CUPRAC and DPPH). The inhibitory properties of V. myrtillus L. extracts may provide a new direction in the development and research of new pharmaceuticals for the suppression of postprandial hyperglycemia in diabetic patients.

Lavandula stoechas L. subsp. stoechas, a New Herbal Source for Ursolic Acid: Quantitative Analysis, Purification and Bioactivity Studies

In this study, methanol, ethanol, methanol-dichloromethane (1 : 1, v/v), acetone, ethyl acetate, diethyl ether, and chloroform extracts of lavender (Lavandula stoechas L. subsp. stoechas) were prepared by maceration, and the ursolic acid contents in the extracts were determined quantitatively by HPLC analyses. The present results show that the methanol-dichloromethane (1 : 1, v/v) solvent system is the most efficient solvent system for the extraction of ursolic acid from the plant sample with the highest yield (2.22 g/100 g plant sample). In the present study, a new practical method for the isolation of ursolic acid from polar extracts was also demonstrated for the first time. The inhibition effects of the extracts and ursolic acid were also revealed on α-glycosidase, acetylcholinesterase, butyrylcholinesterase, and human carbonic anhydrase I and II enzymes by determining IC50 values for the first time. The extracts and ursolic acid acted as potent antidiabetic agents by strongly inhibiting the α-glycosidase activity, whereas they were found to be very weak neuroprotective agents. In view of the present results, L. stoechas and its major metabolite, ursolic acid, can be recommended as a herbal source to control postprandial blood sugar levels and prevent diabetes by delaying the digestion of starch in food.

Bioactive compounds from Polygonatum genus as anti-diabetic agents with future perspectives

Diabetes mellitus (DM) is one of the most serious health problems worldwide. Species in the genus Polygonatum are traditional food and medicinal plants, which play an important role in controlling blood glucose. In this reveiw, we systematically summarized the traditional and modern applications of the genus Polygonatum in DM, focused on the material bases of polysaccharides, flavonoids and saponins. We highlighted their mechanisms of action in preventing obese diabetes, improving insulin resistance, promoting insulin secretion, regulating intestinal microecology, inhibiting advanced glycation end products (AGEs) accumulation, suppressing carbohydrate digestion and obsorption and modulating gluconeogenesis. Based on the safety and efficacy of this 'medicinal food' and its utility in the prevention and treatment of diabetes, we proposed a research and development program that includs diet design (supplementary food), medical nutrition therapy and new drugs, which could provide new pathways for the use of natural plants in prevention and treatment of DM.

Deep eutectic solvent combined with ultrasound technology: A promising integrated extraction strategy for anthocyanins and polyphenols from blueberry pomace

To avoid wasting blueberry pomace resources, deep eutectic solvents (DESs) were combined with ultrasound technology to establish an efficient green method for the recovery of anthocyanins and polyphenols from plant-derived by-products. Choline chloride:1,4-butanediol (molar ratio of 1:3) was chosen as the optimal solvent based on the screening of eight solvents and single-factor experiments. Response surface methodology was applied to optimize the extraction parameters: water content, 29%; extraction temperature, 63 °C; liquid-solid ratio, 36:1 (v/w). The yields of total anthocyanins and total polyphenols from the optimized extraction were 11.40 ± 0.14 mg cyanidin-3-glucoside equiv./g and 41.56 ± 0.17 mg gallic acid equiv./g, respectively, which were both significantly better than the yields achieved with 70% ethanol. The purified anthocyanins showed excellent inhibition of α-glucosidase (IC₅₀ = 16.57 μg/mL). The physicochemical parameters of DES suggest that it can be used for the extraction of bioactive substances.

Ursolic acid regulates gut microbiota and corrects the imbalance of Th17/Treg cells in T1DM rats

Ursolic acid (UA), a natural pentacyclic triterpenoid obtained from fruit and several traditional Chinese medicinal plants, exhibits anti-inflammatory and hypoglycemic properties. However, its protective effects against type 1 diabetes mellitus (T1DM) have not been explored. In this study, streptozotocin-induced T1DM rat models were established and treated with UA for six weeks. T1DM rats treated with UA were used to observe the effects of UA on body weight and fasting blood glucose (FBG) levels. Pathological changes in the pancreas were observed using immunohistochemical staining. The gut microbiota distribution was measured using 16S rDNA high-throughput sequencing. The proportions of Th17 and Treg cells were examined using flow cytometry. Protein and mRNA expression of molecules involved in Th17/Treg cell differentiation were assessed by quantitative real-time PCR and western blotting. The correlation between gut microbiota and Th17/Treg cell differentiation in T1DM was analyzed using redundancy analysis (RDA) analysis. Compared with the model group, FBG levels declined, and the progressive destruction of pancreatic β cells was alleviated. The diversity and uniformity of gut microbiota in T1DM rats treated with UA increased significantly. Interestingly, the Th17/Treg cell differentiation imbalance was corrected and positively correlated with the expression of Foxp3 and IL-10, and negatively correlated with the expression of RORγt, IL-17A, and TNF-α. These findings suggest that UA can lower FBG levels in T1DM rats, delay the progressive destruction of pancreatic β-cells, and modulate gut microbiota homeostasis and immune function in streptozotocin-induced T1DM rats.

Protective mechanisms of loquat leaf extract and ursolic acid against diabetic pro-inflammation

The pharmacological effectiveness of loquat leaf extract (LE) and its important component, ursolic acid (UA), in the treatment of diabetes mellitus, has been well established in traditional medicine; however, the mechanism underlying their action is still unclear. We evaluated the protective effects of LE and UA against hyperglycemia-induced advanced glycation end product (AGE) formations and hepatic pro-inflammation. Oral administration of UA and LE at a dose of 50 mg/kg/day for 15 days yielded no significant hypoglycemic effect in diabetic db/db mice. UA and LE suppressed hepatic oxidative stress and AGE formation in diabetic mice, and this was followed by the downregulated mitogen-activated protein kinase signaling and nuclear factor κ B (NF-κB) activity. To identify the molecular target of LE and UA, a docking simulation was performed, and this predicted UA to bind to liver kinase B1 (LKB1), an upstream of AMP-activated protein kinase (AMPK)/transcription factor forkhead box O3 (FOXO3) axis. UA reversed the high-glucose-induced downregulation of LKB1-AMPK1-FOXO3 activation and antioxidant gene transcription. These findings demonstrated the antioxidant and anti-inflammatory effects of UA and LE against hyperglycemia-induced hepatic inflammation. Furthermore, we speculate that the LKB1/AMPK/FOXO3 pathway is a potential target responsible for these beneficial effects of LE and UA.

Recent Advances Regarding the Molecular Mechanisms of Triterpenic Acids: A Review (Part I)

Triterpenic acids are phytocompounds with a widespread range of biological activities that have been the subject of numerous in vitro and in vivo studies. However, their underlying mechanisms of action in various pathologies are not completely elucidated. The current review aims to summarize the most recent literature, published in the last five years, regarding the mechanism of action of three triterpenic acids (asiatic acid, oleanolic acid, and ursolic acid), corelated with different biological activities such as anticancer, anti-inflammatory, antidiabetic, cardioprotective, neuroprotective, hepatoprotective, and antimicrobial. All three discussed compounds share several mechanisms of action, such as the targeted modulation of the PI3K/AKT, Nrf2, NF-kB, EMT, and JAK/STAT3 signaling pathways, while other mechanisms that proved to only be specific for a part of the triterpenic acids discussed, such as the modulation of Notch, Hippo, and MALAT1/miR-206/PTGS1 signaling pathway, were highlighted as well. This paper stands as the first part in our literature study on the topic, which will be followed by a second part focusing on other triterpenic acids of therapeutic value.

Hypoglycaemic activity of Oleanonic acid, a 3-oxotriterpenoid isolated from Aidia Genipiflora (DC.) Dandy, involves inhibition of carbohydrate metabolic enzymes and promotion of glucose uptake

The present study evaluated the antidiabetic activities of the 70% ethanol stem bark extract of Aidia genipiflora (AGB) and one of its constituents, oleanonic acid in streptozotocin (40 mg/kg)-induced diabetic rats. In vitro assays of glucose uptake and inhibition of carbohydrate metabolizing enzymes were then used to investigate their mechanism(s) of hypoglycaemic action. In silico evaluation of the pharmacokinetic and toxicity properties of the compound was also carried out. Administration of AGB (100-400 mg/kg) and oleanonic acid (15 - 60 mg/kg) resulted in significant reductions (p < 0.001) in the blood glucose and considerable decrease (p < 0.05) in the elevated lipid parameters of the diabetic animals. AGB activity at 200 and 400 mg/kg; and oleanonic acid at 60 mg/kg were comparable to glibenclamide (5 mg/kg). The extract and its isolate strongly inhibited α-glucosidase and α-amylase activity with IC₅₀ values of (10.48 ± 1.39 µg/mL and 14.51 ± 1.26 µg/mL) and (36.52 ± 1.95 µM and 105.84 ± 1.08 µM) respectively. The glucose uptake assays showed that AGB and oleanonic acid exerted both insulin-dependent and independent promotional effect of glucose transport into the periphery by upregulating the expression of PI3K and PPARγ transcripts with a concomitant increase in GLUT-4 transcripts. Although oleanonic acid was predicted to be teratogenic, it was found to be generally non-lethal with favourable pharmacokinetics properties making it suitable for further studies. The study has shown that the stem bark of A. genipiflora is a source of new hypoglycaemic agents and that oleanonic acid possesses hypoglycaemic and anti-hyperlipidaemic activities.

Inhibition of α-Glucosidase, Acetylcholinesterase, and Nitric Oxide Production by Phytochemicals Isolated from Millettia speciosa—In Vitro and Molecular Docking Studies

The phytochemical constituents from the roots of Millettia speciosa were investigated by chromatographic isolation, and their chemical structures were characterized using the MS and NMR spectroscopic methods. A total of 10 compounds, including six triterpenoids, two flavonoids, and two phenolic compounds, were identified from the roots of M. speciosa. Out of the isolated compounds, eight showed inhibitory effects on NO production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells, with IC₅₀ values ranging from 43.9 to 449.5 µg/mL. Ursane-type triterpenes significantly suppressed NO production compared to the remaining compounds. In addition, these compounds also exhibited remarkable inhibitory effects on α-glucosidase. Among the tested compounds, 4, 5, and 10 exhibited excellent α-glucosidase inhibition, with IC₅₀ values ranging from 1.1 to 2.2 µg/mL. Almost all of the test compounds showed little or no acetylcholinesterase inhibition, except for 5, which showed moderate anti-acetylcholinesterase activity in vitro. The molecular docking study of α-glucosidase inhibition by 3–5 and 10 was conducted to observe the interactions of these molecules with the enzyme. Compounds 4, 5, and 10 exhibited a better binding affinity toward the targeted receptor and the H-bond interactions located at the entrance of the enzyme active site pocket in comparison to those of 3 and the positive control acarbose. Our findings evidence the pharmacological potential of this species and suggest that the phytochemicals derived from the roots of M. speciosa may be promising lead molecules for further studies on the development of anti-inflammatory and anti-diabetes drugs.

A Systematic Review of Orthosiphon stamineus Benth. in the Treatment of Diabetes and Its Complications

(1) Background: Orthosiphon stamineus Benth. is a traditional medicine used in the treatment of diabetes and chronic renal failure in southern China, Malaysia, and Thailand. Diabetes is a chronic metabolic disease and the number of diabetic patients in the world is increasing. This review aimed to systematically review the effects of O. stamineus in the treatment of diabetes and its complications and the pharmacodynamic material basis. (2) Methods: This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the databases ScienceDirect, PubMed, and Web of Science. (3) Results: Thirty-one articles related to O. stamineus and diabetes were included. The mechanisms of O. stamineus in the treatment of diabetes and its complications mainly included inhibiting α-amylase and α-glucosidase activities, antioxidant and anti-inflammatory activities, regulating lipid metabolism, promoting insulin secretion, ameliorating insulin resistance, increasing glucose uptake, promoting glycolysis, inhibiting gluconeogenesis, promoting glucagon-likepeptide-1 (GLP-1) secretion and antiglycation activity. Phenolic acids, flavonoids and triterpenoids might be the main components for hypoglycemia effects in O. stamineus. (4) Conclusion: O. stamineus could be an antidiabetic agent to treat diabetes and its complications. However, it needs further study on a pharmacodynamic substance basis and the mechanisms of effective constituents.

Network Pharmacology and Transcriptomics Reveal the Mechanism of GuaLouQuMaiWan in Treatment of Type 2 Diabetes and Its Active Small Molecular Compound

The main pathophysiological abnormalities in type 2 diabetes (T2D) include pancreatic β-cell dysfunction and insulin resistance. Due to hyperglycemia, patients receive long-term treatment. However, side effects and drug tolerance usually lead to treatment failure. GuaLouQuMaiWan (GLQMW), a common traditional Chinese medicine (TCM) prescription, has positive effects on controlling blood sugar and improving quality of life, but the mechanism is still unclear. To decipher their molecular mechanisms, we used a novel computational systems pharmacology-based approach consisting of bioinformatics analysis, network pharmacology, and drug similarity comparison. We divided the participants into nondisease (ND), impaired glucose tolerance (IGT), and type 2 diabetes groups according to the WHO's recommendations for diabetes. By analyzing the gene expression profile of the ND-IGT-T2D (ND to IGT to T2D) process, we found that the function of downregulated genes in the whole process was mainly related to insulin secretion, while the upregulated genes were related to inflammation. Furthermore, other genes in the ND-IGT (ND to IGT) process are mainly related to inflammation and lipid metabolic disorders. We speculate that 17 genes with a consistent trend may play a key role in the process of ND-IGT-T2D. We further performed target prediction for 50 compounds in GLQMW that met the screening criteria and intersected the differentially expressed genes of the T2D process with the compounds of GLQMW; a total of 18 proteins proved potential targets for GLQMW. Among these, RBP4 is considerably related to insulin resistance. GO/KEGG enrichment analyses of the target genes of GLQMW showed enrichment in inflammation- and T2D therapy-related pathways. Based on the RDKit tool and the DrugBank database, we speculate that (-)-taxifolin, dialoside A_qt, spinasterol, isofucosterol, and 11,14-eicosadienoic acid can be used as potential drugs for T2D via molecular docking and drug similarity comparison.

Development, Physical-Chemical Characterization, and Molecular Docking Simulations of Ursolic Acid-Sodium Alginate Complexes

The aim of this study was to fabricate ursolic acid (UA)-sodium alginate (SA) complexes to improve the dissolution rate and antioxidant abilities. The antioxidant activity was evaluated by the DPPH (1,1-diphenyl-2-trinitrophenylhydrazine) assay and the pyrogallol auto-oxidation method. For the optimal composition ratio of UA:SA (1:5, w/w), the cumulative release of UA was about 101.22 ± 1.50% for 180 min. Powder X-ray diffractometry (PXRD), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM) analyses confirmed that the crystallinity of UA was significantly reduced by forming complexes with SA. By Fourier transform infrared spectroscopy (FTIR) and molecular docking simulations, it was observed that the hydroxyl group in UA formed hydrogen bonding with the carbonyl group in SA. The DPPH scavenger activities of the complexes were also increased compared with free UA. The results indicated that SA could serve as a promising carrier for lipophilic functional food ingredients due to improved solubility and antioxidant activity.

Inhibition Mechanism of α-Amylase/α-Glucosidase by Silibinin, Its Synergism with Acarbose, and the Effect of Milk Proteins

As a natural flavonolignan, silibinin is reported to possess multiple biological activities, while the inhibitory potential of silibinin on carbohydrate-hydrolyzing enzymes is still unclear. Therefore, in this study, the inhibitory effect and underlying mechanism of silibinin against α-amylase/α-glucosidase were investigated. The results indicated that silibinin showed a strong inhibitory efficiency against α-amylase/α-glucosidase in noncompetitive manners and exhibited synergistic inhibition against α-glucosidase with acarbose. However, interestingly, the inhibitory effect of silibinin was significantly hindered in various milk protein-rich environments, but this phenomenon disappeared after simulated gastrointestinal digestion of milk proteins in vitro. Furthermore, silibinin could combine with the inactive site of α-amylase/α-glucosidase and change the microenvironment and secondary structure of the enzymes, thereby influencing the catalytic efficiency of enzymes. This research suggested that silibinin could be used as a novel carbohydrate-hydrolyzing enzyme inhibitor, and milk beverages rich in silibinin had the potential for further application in antidiabetic dietary or medicine.

Spectroscopic and computational studies on the binding interaction between gallic acid and Pin1

Gallic acid (GA) is a natural ingredient in functional foods, which has various health-promoting and antitumour effects. Peptidyl-prolyl cis/trans isomerase Pin1 plays an important role in preventing the development of some malignant tumours. However, whether there was an interaction between Pin1 and GA remains unknown. In this work, the binding information of GA and Pin1 was investigated systematically using multiple spectral and computational methods. GA bound to Pin1 directly with moderate binding affinity in the order of 10⁴  mol/L, therefore decreasing the activity of Pin1. Also, the binding process of GA to Pin1 was driven through weak van der Waals forces, hydrogen bonds, and electrostatic forces. In addition, the important residues Lys63, Arg68, and Arg69 played a significant role in maintaining the binding stability between Pin1 and GA. Interestingly, GA reduced the activity of Pin1 by affecting its conformational characteristics. Our present work showed that GA binds to Pin1 and inhibits its activity, affecting its structural and functional properties, which may contribute to the therapy of Pin1-related diseases.

Ursolic Acid-Based Derivatives as Potential Anti-Cancer Agents: An Update

Ursolic acid is a pharmacologically active pentacyclic triterpenoid derived from medicinal plants, fruit, and vegetables. The pharmacological activities of ursolic acid have been extensively studied over the past few years and various reports have revealed that ursolic acid has multiple biological activities, which include anti-inflammatory, antioxidant, anti-cancer, etc. In terms of cancer treatment, ursolic acid interacts with a number of molecular targets that play an essential role in many cell signaling pathways. It suppresses transformation, inhibits proliferation, and induces apoptosis of tumor cells. Although ursolic acid has many benefits, its therapeutic applications in clinical medicine are limited by its poor bioavailability and absorption. To overcome such disadvantages, researchers around the globe have designed and developed synthetic ursolic acid derivatives with enhanced therapeutic effects by structurally modifying the parent skeleton of ursolic acid. These structurally modified compounds display enhanced therapeutic effects when compared to ursolic acid. This present review summarizes various synthesized derivatives of ursolic acid with anti-cancer activity which were reported from 2015 to date.