α-Glucosidase inhibitory triterpenoids from Euonymus fortunei

Bioactive Phenylpropanoid Glycosides, Dimers, and Heterodimers from the Bark of Cinnamomum cassia (L.) J.Presl

Six new phenylpropanoid glycosides (1-6), two new phenylethanol glycosides (7 and 8), one new phenylmethanol glycoside (9), three new phenylpropanoid dimers (10-12), two new phenylpropanoid-flavan-3-ol heterodimers (13 and 14), and six known relevant compounds (15-20) were isolated and identified from the well-liked edible and medicinal substance (the bark of Cinnamomum cassia (L.) J.Presl). The structures of these isolates were determined by using spectroscopic analyses, chemical methods, and quantum chemical calculations. Notably, compounds 4-9 were rare apiuronyl-containing glycosides, and compounds 13 and 14 were heterodimers of phenylpropanoids and flavan-3-ols linked through C-9″-C-8 bonds. The antioxidant and α-glucosidase inhibitory activities of all isolates were evaluated. Compounds 10 and 12 exhibited DPPH radical scavenging capacities with IC50 values of 20.1 and 13.0 μM, respectively (vitamin C IC50 value of 14.3 μM). In the ORAC experiment, all these compounds exhibited different levels of capacity for scavenging free radicals, and compound 10 displayed extraordinary free radical scavenging capacity with the ORAC value of 6.42 ± 0.01 μM TE/μM (EGCG ORAC value of 1.54 ± 0.02 μM TE/μM). Compound 12 also showed significant α-glucosidase inhibitory activity with an IC50 of 56.3 μM (acarbose IC50 of 519.4 μM).

Medicinal patterns of vines used in Chinese herbal medicine: a quantitative study

ETHNOPHARMACOLOGICAL RELEVANCE

The botanical characteristics of twinning, climbing vine plants conceptually take shape to interlink the meridians and collaterals system throughout the human body by expelling climatic evils (e.g., wind, dampness). Thus, vines have displayed great medicinal properties in traditional Chinese medicine (TCM).

AIM OF THE STUDY

Although some popular vine species have been intensively investigated, the comparable features and medicinal specifications among a vast collection of taxonomic groups based on data visualization methods are relatively lacking in attention. Moreover, the translatability of vines from ancient ethnomedical evidence to modern medical system has not been well established. This review tends to quantitatively summarize the strength of vines in healthcare from the perspectives of medicinal part, traditional function, clinical spectrum, phytochemistry divergence, pharmacological attributes, toxicity as well as the progress of proprietary drug development.

MATERIALS AND METHODS

Medicinal vines were retrieved from databases of drug standards and curated catalogues. Synonyms of plant origin across different datasets were normalized by accepted scientific names in the World Flora Online. The distribution patterns and rank of plant origin, medicinal parts, traditional functions and target conditions, as well as the correlation between phytochemical composition and clinical applications were analyzed and visualized.

RESULTS

A total of 121 crude drugs from 36 families, 77 genera, 133 species of vines were obtained and analyzed. The Fabaceae, Menispermaceae and Rubiaceae were the highest ranked families of medicinal vines. Not surprisingly, stem was the most dominant medical part. Moreover, "eliminate wind" displayed a hub node in the traditional function co-occurrence network. In addition to joint impediment disorders, these vines particularly displayed a wide range of therapeutic modalities toward conditions from various organ systems. Chemotaxonomic properties-oriented phytochemical analysis was performed and the chemical diversity among medicinal vines complementarily determined a certain group of therapeutic domains. Particularly, the anti-inflammatory effect and antiarthritic effect were highlighted for treating rheumatic diseases. Using integral animal models and cultured cells, modern pharmacological actions of medicinal vines have been largely observed and validated according to their traditional ethnopharmacology. Furthermore, a small proportion of vine species are well-known toxic plants. Successful drug development pipelines in rheumatic, cardiovascular, liver, malignant and infectious diseases have offered the capacity to generate new treatment options that are being sought out from vine plants.

CONCLUSIONS

Medicinal vines are rich sources of Chinese Material Medica (CMM) and good fit for a variety of clinical manifestations beyond arthritis and rheumatic diseases. In addition to stem, other parts are also popular for both medicines and dietary supplements. Vine plants provide extensive biologically relevant chemical space for developing value-creating drugs. Thus, our analysis can be useful for further motivating and strengthening the preclinical and clinical research of vine-derived remedies.

Enzyme immobilized on magnetic fluorescent bifunctional nanoparticles for α-glucosidase inhibitors virtual screening from Agrimonia pilosa Ledeb extracts accompanied with molecular modeling

Agrimonia pilosa Ledeb (APL) is a significant source of inhibitors for α-glucosidase, which is an essential target enzyme for the treatment of type 2 diabetes, cancer and acquired immune deficiency syndrome. Ligand fishing is a suitable approach for the highly selective screening of bioactive substances in complex mixtures. Yet it is unable to conduct biomedical imaging screening, which is crucial for real-time identification. In this case, a bioanalytical platform combining magnetic fluorescent ligand fishing and in-situ imaging technique was established for the screening and identification of α-glucosidase inhibitors (AGIs) from APL crude extract, utilizing α-glucosidase coated CuInS2/ZnS-Fe3O4@SiO2 (AG-CIZSFS) nanocomposites as extracting material and fluorescent tracer. The AG-CIZSFS nanocomposites prepared through solvothermal and crosslinking methods displayed fast magnetic separation, excellent fluorescence performance and high enzyme activity. The tolerance of immobilized enzyme to temperature and pH was stronger than that of free enzyme. Prior to proof-of-concept with APL crude extract, a number essential parameters (glutaraldehyde concentration, immobilized time, enzyme amount, reaction solution pH, incubation temperature, incubation time, percentage of methanol in eluen, elution times and eluent volume) were optimized using an artificial test mixture. The fished ligands were identified by UPLC-MS/MS and their biological activities were preliminarily evaluated by real-time cellular morphological imaging of human colon carcinoma (HCT-116) cells based on confocal laser scanning microscope (CLSM). Their α-glucosidase inhibitory activities were further verified and studied by classical pNPG method and molecular docking. The isolated compounds exhibited significant α-glucosidase inhibitory activities with a IC50 value of 11.57 µg·mL-1. Six potential AGIs including tribuloside, ivorengenin A, tormentic acid, 1β, 2β, 3β, 19α-Tetra hydroxyurs-12-en-28-oic acid, corosolic acid and pomolic acid were ultimately screened out and identified from APL crude extracts. The proposed approach, which combined highly specific screening with in-situ visual imaging, provided a powerful platform for discovering bioactive components from multi-component and multi-target traditional Chinese medicine (TCM).

Arylureidoaurones: Synthesis, in vitro α-glucosidase, and α-amylase inhibition activity

Because of the colossal global burden of diabetes, there is an urgent need for more effective and safer drugs. We designed and synthesized a new series of aurone derivatives possessing phenylureido or bis-phenylureido moieties as α-glucosidase and α-amylase inhibitors. Most of the synthesized phenylureidoaurones have demonstrated superior inhibition activities (IC50s of 9.6-339.9 μM) against α-glucosidase relative to acarbose (IC50 = 750.0 μM) as the reference drug. Substitution of aurone analogues with two phenylureido substituents at the 5-position of the benzofuranone moiety and the 3' or 4' positions of the 2-phenyl ring resulted in compounds with almost 120-180 times more potent inhibitory activities than acarbose. The aurone analogue possessing two phenylureido substitutions at 5 and 4' positions (13) showed the highest inhibition activity with an IC50 of 4.2 ± 0.1 μM. Kinetic studies suggested their inhibition mode to be competitive. We also investigated the binding mode of the most potent compounds using the consensually docked 4D-QSAR methodology. Furthermore, these analogues showed weak-to-moderate non-competitive inhibitory activity against α-amylase. 5-Methyl substituted aurone with 4'-phenylureido moiety (6e) demonstrated the highest inhibition activity on α-amylase with an IC50 of 142.0 ± 1.6 μM relative to acarbose (IC50 = 108 ± 1.2 μM). Our computational studies suggested that these analogues interact with a hydrophilic allosteric site in α-amylase, located far from the enzyme active site at the N-terminal.

Exploring plant-based alpha-glucosidase inhibitors: promising contenders for combatting type-2 diabetes

Objective: This systematic review aimed to provide comprehensive details on the α-G inhibitory potential of various bioactive compounds derived from natural sources.Methods: A comprehensive literature search was conducted using various databases and search engines, including Science Direct, Google Scholar, SciFinder, Web of Science, and PubMed until May, 2023.Results and conclusions: The enzyme alpha-glucosidase (α-G) is found in the brush border epithelium of the small intestine and consists of duplicated glycoside hydrolase (GH31) domain. It involves the conversion of disaccharides and oligosaccharides into monosaccharides by acting on alpha (1 → 4) and (1 → 6) linked glucose residue. Once absorbed, glucose enters the bloodstream and elevates postprandial glucose, which is associated with the development of type 2 Diabetes (T2D). Epidemic obesity, cardiovascular disease, and nephropathy are linked to T2D. Traditional medicinal plants with α-G inhibitory potential are commonly used to treat T2D due to the adverse effects of currently used α-G inhibitors miglitol, acarbose, and voglibose. Various bioactive compounds derived from natural sources, including lupenone, Wilforlide A, Baicalein, Betulinic acid, Ursolic acid, Oleanolic acid, Katononic acid, Carnosol, Hypericin, Astilbin, lupeol, betulonic acid, Fagomine, Lactucaxanthin, Erythritol, GP90-1B, Procyanidins, Galangin, and vomifoliol retain α-G inhibitory potential for regulating hyperglycaemia.

Bioaffinity ultrafiltration coupled with HPLC-ESI-MS/MS for screening potential α-glucosidase inhibitors from pomegranate peel

Pomegranate peel (PoP) contains plenty of bioactive compounds and exhibits strong activity to prevent postprandial hyperglycaemia and improve diabetes mellitus. Presently, bioaffinity ultrafiltration coupled with high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS/MS) is employed to screen and identify the efficient α-glucosidase inhibitors in PoP and the detailed inhibitory mechanisms are further investigated. The results show that many substances, including ellagic acid, kaempferol, gallic acid, and resveratrol in PoP reveal strong activity to inhibit α-glucosidase and ellagic acid (EA) is screened as the most effective compound. Further research indicates that EA plays a competitive and reversible inhibition role against α-glucosidase with the value of Ki was 6.24 × 105 mol/L. EA also directly interacts with the amino acids of α-glucosidase mainly via van der Waals forces and hydrogen bonds, thereby, influencing the secondary structure and stability of α-glucosidase. Finally, the α-glucosidase inhibitory activity of EA is further confirmed to significantly reduce postprandial blood glucose in vivo.

Simultaneous Determination and Pharmacokinetics Study of Three Triterpenes from Sanguisorba officinalis L. in Rats by UHPLC–MS/MS

A selective and rapid ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method was established and validated for the determination of ziyuglycoside I, 3β,19α-dihydroxyurs-12-en-28-oic-acid 28-β-d-glucopyranosyl ester, and pomolic acid in rats after the oral administration of ziyuglycoside I, 3β,19α-dihydroxyurs-12-en-28-oic-acid 28-β-d-glucopyranosyl ester, pomolic acid, and Sanguisorba officinalis L. extract. The separation was carried out on an ACQUITY UPLC^®HSS T₃ column (2.1 mm × 100 mm, 1.8 μm), using methanol and 5 mmol/L ammonium acetate water as the mobile phase. The three compounds were quantified using the multiple reaction monitoring mode with the electrospray ion source in both the positive and negative mode. Liquid-liquid extraction was applied to the plasma sample preparation. Bifendate was selected as the internal standard. The intra-day and inter-day precision and the accuracy of the method were all within receivable ranges. The lower limit of quantification of ziyuglycoside I, 3β,19α-dihydroxyurs-12-en-28-oic-acid 28-β-d-glucopyranosyl ester, and pomolic acid were 6.50, 5.75, and 2.63 ng/mL, respectively. The extraction recoveries of analytes in rat plasma ranged from 83 to 94%. The three components could be rapidly absorbed into the blood (T_max, 1.4–1.6 h) both in the single-administration group or S. officinalis extract group, but the first peak of PA occurred at 0.5 h and the second peak at 4–5 h in the S. officinalis extract. Three compounds were eliminated relatively slowly (t_1/2, 7.3–11 h). The research was to establish a rapid, sensible, and sensitive UHPLC–MS/MS method using the multi-ion mode for multi-channel simultaneous mensuration pharmacokinetics parameters of three compounds in rats after oral administration of S. officinalis extract. This study found, for the first time, differences in the pharmacokinetic parameters of the three compounds in the monomer compounds and S. officinalis extract administration, which preliminarily revealed the transformation and metabolism of the three compounds in vivo.

α-Glucosidase inhibitory effect of an anthraquinonoid produced by Fusarium incarnatum GDZZ-G2

α-Glucosidase is the key enzyme on carbohydrate metabolism, and its bioactive inhibitors are supposed to be an effective therapeutic for type 2 diabetes mellitus. During our continuing study for discovering α-glucosidase inhibitors, a fungus GDZZ-G2 which is derived from a medicinal plant Callicarpa kwangtungensis Chun, exhibited significant inhibition on α-glucosidase. The strain was identified as Fusarium incarnatum by morphological and molecular methods. Further bioassay-guided fractionation result in six known secondary metabolites (1-6). All the compounds except 4 were isolated from F. incarnatum for the first time. Among them, an anthraquinonoid (S)-1,3,6-trihydroxy-7-(1-hydroxyethyl)anthracene-9,10-dione (compound 1) exhibited strong inhibitory effect against α-glucosidase (IC₅₀  = 77.67 ± 0.67 μΜ), compared with acarbose (IC₅₀  = 711.8 ± 5 μΜ). An enzyme kinetics analysis revealed that compound 1 was an uncompetitive inhibitor. Besides, docking simulations predicted that compound 1 inhibited α-glucosidase substrate complex by binding Gln322, Gly306, Thr307, and Ser329 through hydrogen-bond interactions. Our findings suggested that compound 1 can be considered a lead compound for further modifications and the development of a new effective drug candidate in the treatment of type 2 diabetes mellitus.

Terpenoids with α-glucosidase inhibitory activity from Rhododendron minutiflorum Hu

Five undescribed triterpenoids, two unusual omphalane-type sesquiterpenoids together with twenty-five known compounds were isolated from the leaves and stems of Rhododendron minutiflorum Hu. The absolute configurations of 1-3 and 6 were established by single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD). Compounds 6-7 feature the rare omphalane-type sesquiterpene skeleton and are verified by single-crystal X-ray diffraction analysis for the first time. In the biological activity assay, most of the triterpenoids have different degrees of inhibitory effects on α-glucosidase, with IC₅₀ values ranging from 6.97 to 229.3 μM (the positive control drug acarbose has an IC₅₀ value of 3.07 × 10^-3 μM). Structure and activity relationship (SAR) study reveals that the oxidation degrees of C-3, C-8, or C-11 to C-13 of the ursane-type triterpenoid influence the inhibitory activity dramatically.