α-Glucosidase inhibitors isolated from medicinal plants

Apigenin ameliorates chronic mild stress-induced depressive behavior by inhibiting interleukin-1β production and NLRP3 inflammasome activation in the rat brain

Medicinal importance, pharmacological activities, and analytical aspects of hispidulin: A concise report.

Phenylethanoid glycosides (PhGs) are widely distributed in traditional Chinese medicines as well as in other medicinal plants, and they were characterized by a phenethyl alcohol (C6-C2) moiety attached to a β-glucopyranose/β-allopyranose via a glycosidic bond. The outstanding activity of PhGs in diverse diseases proves their importance in medicinal chemistry research. This review summarizes new findings on PhGs over the past 10 years, concerning the new structures, their bioactivities, including neuroprotective, anti-inflammatory, antioxidant, antibacterial and antivirus, cytotoxic, immunomodulatory, and enzyme inhibitory effects, and pharmacokinetic properties.

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Phenylethanoid Glycosides: Research Advances in Their Phytochemistry, Pharmacological Activity and Pharmacokinetics.

Developing techniques for isolation and identification of biocompounds, from natural products, resulted in a rapid enrichment of carotenoid pigments number. For their isolation from biometabolites mixtures, the physical and chemical properties are taken into account. Carotenoids are sensitive to light, heat, oxygen, acids and alkaline bases. The exposure to light (direct sunlight/ UltraViolet), causes cis–trans photoisomerization, which may lead to their photodestruction. Biological materials containing carotenoids and their solutions must be protected from the action of light. Many carotenoids are thermolabile (xanthophylls); their heating being indicated only when it is absolutely necessary. The separation of carotenoids is done at room temperature or up to –20°C, in the dark. In the case of hot saponification they should be protected by a low–boiling solvent (30–60°C). Carotenoids may be oxidized in the presence of oxygen or peroxides, because of their sensitivity to oxygen in the adsorbed state (in thin layer or column chromatograms). It is necessary to operate in inert conditions (under nitrogen or vacuum). The oxidation during the extraction and saponification can be minimized if it is carried out in a nitrogen atmosphere. The exposure of carotenoids to acids, leads to changes such as: the oxidative decomposition, cis–trans isomerization and isomerization of 5,6–epoxides and 5,8–epoxides. The inconveniences are minimized by neutralization (calcium carbonate, pyridine, dimetilalanine). It works with purified solvents, freshly distilled, chlorinated derivatives (dichloromethane or solvents containing hydrochloric acid). The storage of carotenoids should be done in the dark, under an atmosphere of nitrogen or in vacuum, at a temperature of –20°C. The best preservation method is in the crystalline state. The current research techniques are using spectral methods, which provide accurate information on the structure and properties of organic biosubstances. Compared to chemical methods of identification, spectral methods have the advantage that it provides data faster, are accurate, require small amounts of material and enable continuous analysis at different stages of processing of the compound extracted without changing the composition of the biosubstance investigated, which enables its recovery. This chapter presents the main methods of extraction, separation and identification of organic compounds with direct applications on carotenoids.

Methods of Analysis (Extraction, Separation, Identification and Quantification) of Carotenoids from Natural Products

Diterpenoids and phenylethanoid glycosides from the roots of Clerodendrum bungei and their inhibitory effects against angiotensin converting enzyme and α-glucosidase.

Phytochemical analysis of Panax species: a review.

Six new diterpenoids, 4-epi-7α-O-acetylscoparic acid A (1), 7α-hydroxyscopadiol (2), 7α-O-acetyl-8,17β-epoxyscoparic acid A (3), neo-dulcinol (4), dulcinodal-13-one (5), and 4-epi-7α-hydroxydulcinodal-13-one (6), and a new flavonoid, dillenetin 3-O-(6″-O-p-coumaroyl)-β-d-glucopyranoside (10), along with 12 known compounds, were isolated from the aerial parts of Scoparia dulcis. The 7S absolute configuration of the new diterpenoids 1–4 and 6 was deduced by comparing their NOESY spectra with that of a known compound, (7S)-4-epi-7-hydroxyscoparic acid A (7), which was determined by the modified Mosher’s method. The flavonoids scutellarein (11), hispidulin (12), apigenin (15), and luteolin (16) and the terpenoids 4-epi-scopadulcic acid B (9) and betulinic acid (19) showed more potent α-glucosidase inhibitory effects (with IC50 values in the range 13.7–132.5 μM) than the positive control, acarbose. In addition, compounds 1, 11, 12, 15, 16, and acerosin (17) exhibited peroxisome proliferator-activated receptor ...

Bioactive diterpenoids and flavonoids from the aerial parts of Scoparia dulcis

Alpha-glucosidase inhibitors currently form an important basis for developing novel drugs for diabetes treatment. In our preliminary tests, the ethyl acetate fraction of Phlomis tuberosa extracts showed significant α-glucosidase inhibitory activity (IC₅₀ = 100 μg/mL). In the present study, a combined method using Sepbox chromatography and thin-layer chromatography (TLC) bioautography was developed to probe α-glucosidase inhibitors further. The ethyl acetate fraction of P. tuberosa extracts was separated into 150 individual subfractions within 20 h using Sepbox chromatography. Then, under the guidance of TLC bioautography, 20 compounds were successfully isolated from these fractions, including four new diterpenoids [14-hydroxyabieta-8,11,13-triene-11-carbaldehyde-18-oic-12-carboxy-13-(1-hydroxy-1-methylethyl)-lactone (1), 14-hydroxyabieta-8,11,13-triene-17-oic-12-carboxy-13-(1-hydroxy-1-methylethyl)-lactone (2), 14,16-dihydroxyabieta-8,11,13-triene-15,17-dioic acid (3), and phlomisol (15,16-eposy-8,13(16),14-labdatrien-19-ol) (4)], and 16 known compounds. Activity estimation indicated that 15 compounds showed more potent α-glucosidase inhibitory effects (with IC50 values in the range 0.067–1.203 mM) than the positive control, acarbose (IC50 = 3.72 ± 0.113 mM). This is the first report of separation of α-glucosidase inhibitors from P. tuberosa.

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Yingbo Yang

Papers

Diterpenoids and phenylethanoid glycosides from the roots of Clerodendrum bungei and their inhibitory effects against angiotensin converting enzyme and α-glucosidase.

Phytochemical analysis of Panax species: a review.

Bioactive diterpenoids and flavonoids from the aerial parts of Scoparia dulcis

Rapid identification of α-glucosidase inhibitors from Phlomis tuberosa by Sepbox chromatography and thin-layer chromatography bioautography.

Notoginsenoside Ft1 acts as a TGR5 agonist but FXR antagonist to alleviate high fat diet-induced obesity and insulin resistance in mice