The chemical constituents and hypoglycemic activity of alcoholic extract of sea buckthorn leaves / 药学学报

The purpose of this research is to identify the chemical constituents of sea buckthorn leaves extract (SBLE) and explore its hypoglycemic biological activity. SBLE was prepared by hot reflux extraction with 65% ethanol, and its chemical composition was analyzed by ultra-high-performance liquid chromatography-photodiode array-mass spectrometry/mass spectrometry (UHPLC-PDA-MS/MS) system. The animal experiments were compliant with ethical principles for animal use and had been approved by the Animal Experiment Ethics Committee of Jinan University. Mice were injected with streptozocin (STZ) to establish a hyperglycemic animal model, and SBLE (1.5 g·kg-1) was administered by gavage for 5 weeks. The fasting blood glucose (FBG) and oral glucose tolerance were detected. Normal mice were given SBLE (1.5 g·kg-1) by intragastric administration for 10 days, and blood was collected from the tail vein to detect the changes in blood glucose within 120 min after sucrose or starch loading. The mucous membrane of the small intestine of mice was taken to detect the activity of α-glucosidase (AG), and the activity of yeast-derived AG incubated with SBLE was evaluated. The glucose uptake by Caco-2 cells treated with SBLE was detected by fluorescence microscopy and cytometry, and the gene expression of sodium-dependent glucose transporter 1 (SGLT1) and glucose transporter 2 (GLUT2) in Caco-2 cells were detected by real-time quantitative PCR (qPCR). A total of 18 compounds were identified, mainly including tannins and flavonoids. SBLE reduced FBG and increased oral glucose tolerance in STZ hyperglycemic mice. SBLE effectively inhibited the increase of blood glucose caused by starch intake in normal mice. SBLE exerted good inhibitory activity on yeast-derived AG (IC50 = 16.94 μg·mL-1) and small intestinal mucosa AG with an inhibition rate of 15.48%. SBLE (25-100 μg·mL-1) dose-dependently inhibited glucose uptake by Caco-2 cells, and SBLE significantly reduced the mRNA level of SGLT1 without changing the expression of GLUT2. In conclusion, the UHPLC characteristic fingerprint of SBLE is established with 18 chemical components identified by mass spectrometry, and SBLE exerts hypoglycemic effect by inhibiting the activity of AG and the absorption of glucose by intestinal epithelial cells.

Research on hypoglycemic activity of Osmanthus fragrans var. thunbergii extract / 药学学报

This study aimed to assess the hypoglycemic activity, and in vitro inhibition of α-glucosidase, inhibition of the advanced glycation end products (AGEs), and total antioxidant capacity were used to clarify its bioactivity. Furthermore, the potential hypoglycemic active chemical constituents in the aqueous extract of Osmanthus fragrans var. thunbergii flower were characterized using high performance liquid chromatography-electrospray ionization-quadruple time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) method. The result showed that in vitro inhibition of α-glucosidase of the extract (IC50 = 2.11 ± 0.26 mg·mL-1) were similar to acarbose (IC50 = 2.88 ± 0.32 mg·mL-1), and it inhibited the AGEs formation and the total antioxidant capacity in a certain extent. Based on the MS fragmentation pathway analysis of reference chemical acteoside contained in this extract, and related references, 73 constituents were tentatively identified from the aqueous extract of Osmanthus fragrans var. thunbergii flower, including 58 phenylethanoids, 8 caffeoylquinic acids, 1 flavonoid vicenin-2, and 6 common organic chemicals in plant. Furthermore, 8 unknown alkaloids were characterized in this work. Among of these chemicals, 61 phenylethanoids were supposed to be detected for the first time. In conclusion, this work disclosed the potential hypoglycemic active constituents of Osmanthus fragrans var. thunbergii flower.

Bioassay-guided isolation of α-Glucosidase inhibitory constituents from Hypericum sampsonii / 中国天然药物

This study employed the α-glucosidase inhibitory activity model as an anti-diabetic assay and implemented a bioactivity-guided isolation strategy to identify novel natural compounds with potential therapeutic properties. Hypericum sampsoniiwas investigated, leading to the isolation of two highly modified seco-polycyclic polyprenylated acylphloroglucinols (PPAPs) (1 and 2), eight phenolic derivatives (3-10), and four terpene derivatives (11-14). The structures of compounds 1 and 2, featuring an unprecedented octahydro-2H-chromen-2-one ring system, were fully characterized using extensive spectroscopic data and quantum chemistry calculations. Six compounds (1, 5-7, 9, and 14) exhibited potential inhibitory effects against α-glucosidase, with IC50 values ranging from 0.050 ± 0.0016 to 366.70 ± 11.08 μg·mL-1. Notably, compound 5 (0.050 ± 0.0016 μg·mL-1) was identified as the most potential α-glucosidase inhibitor, with an inhibitory effect about 6900 times stronger than the positive control, acarbose (IC50 = 346.63 ± 15.65 μg·mL-1). A docking study was conducted to predict molecular interactions between two compounds (1 and 5) and α-glucosidase, and the hypothetical biosynthetic pathways of the two unprecedented seco-PPAPs were proposed.

Study on chemical constituents of sponge-associated Aspergillus terreus / 药学实践杂志

Objective To study the chemical constituents of Aspergillus terreus from sponge epiphytic fungal. Methods Sephadex LH-20 column chromatography, silica gel column chromatography and high performance liquid chroma-tography were used to separate and purify the compounds. The structures of compounds were identified by spectroscopic data. The α-glucosidase inhibitory activity and antioxidant activity of the compounds were tested by PNPG and DPPH methods, respectively. Results Eight compounds were isolated from Aspergillus terreus and identified as methyl-3,4,5-trimethoxy-2-(2-(nicotinamido) benzamido) benzoate (1), terrelumamide A (2), emeheterone (3), (8R,9S)-dihydroisoflavipucine (4), (8S,9S)-dihydroisoflavipucine (5), cyclo(S-Pro-S-Phe) (6), brevianamide F (7), terrein (8). Compound 3 showed strong inhibitory activity against α-glucosidase and the IC50 value was 14.28 μmol/L. Conclusion Compounds 3, 4, 5, and 7 were obtained from Aspergillus terreus for the first time.

Effect of Tartary Buckwheat Boiled Noodles on Postprandial Blood Glucose Level and Its Active Components / 日本補完代替医療学会誌

Dry solid matter (rutin content: 51.6 mg/g; quercetin content: 72.2 mg/g) extracted from Tartary buckwheat boiled noodles using 70% methanol as the solvent was found to have α-glucosidase inhibitory activity. As for fractions fractionated by silica gel column chromatography, the fractions rich in quercetin and rutin showed remarkable α-glucosidase inhibitory activity. Tartary buckwheat boiled noodles used as samples in this study contained quercetin produced from rutin by the action of rutinase, suggesting that both rutin and quercetin contained were involved in the α-glucosidase inhibitory activity of the dry solid extract. Changes in postprandial blood glucose levels were compared for boiled noodles made from two types of buckwheat (i.e., Tartary buckwheat and common buckwheat), revealing that blood glucose elevation after eating Tartary buckwheat boiled noodles was suppressed. The blood glucose level 40 minutes after eating Tartary buckwheat boiled noodles was significantly low (p<0.05). It can be concluded that this might be caused by the α-glucosidase inhibitory activity of rutin (270.0 mg) and quercetin (330.5 mg), which correspond to a total amount of 935 mg of rutin equivalents, in the gastrointestinal tract. As a result, the digestion of carbohydrates contained in the samples consumed and their absorption by the intestine might be inhibited, resulting in the suppression of increases in blood glucose levels. The presence of a certain amount of quercetin was considered to be key to the suppression of blood glucose elevation. It is important to control rapid postprandial blood glucose increases to prevent diabetes from developing or becoming serious. This study suggests the potential for Tartary buckwheat boiled noodles to contribute to diabetes prevention.

Chemical composition and hypoglycemic activity of Edgeworthia gardneri / 药学学报

Seven compounds were isolated from the alcohol extract of Edgeworthia gardneri by various technologies, including silica gel, Sephadex LH-20 and high performance liquid chromatography, and were identified as edgeworthiaside A (1), 2,4,6-trichlorol-3-methyl-5-methoxy-phenol 1-O-β-D-glucopyranosyl-(1-6)-β-D-glucopyranoside (2), 2,6-dimethoxy-4-(2-propen-1-yl)phenyl 6-O-(6-deoxy-α-L-mannopyranosyl)-β-D-glucopyranoside (3), eugenol rutinoside (4), tiliroside (5), edgeworoside C (6), and salicylic acid (7). Compound 1 is a new chlorophenyl glycoside and 2-4 were isolated for the first time from Edgeworthia gardneri. The in vitro inhibition of α-glucosidase showed that the inhibition rate of compounds 1 and 2 were similar to acarbose.

Establishment of high-resolution bioassay profiling platform to screen α-glucosidase inhibitors from Malus hupehensis / 药学学报

italic>α-Glucosidase inhibitors play an important role in the treatment of diabetes. This study established a high-resolution bioassay profiling platform for rapidly screening α-glucosidase inhibitors in natural product extracts. Five α-glucosidase inhibitors were identified from Malus hupehensis, namely, 3-hydroxyphloridzin, quercetin-3-O-β-D-glucopyranoside, phloridzin, avicularin and quercitrin. The establishment and successful application of this platform provides a powerful tool for the efficient discovery of anti-diabetic active ingredients in complex systems.

Exploration Of Bioactive Components Of Thunbergia Coccinea, Its Pharmacognostic, Antioxidant, Gcms And Antihyperglycemic Studies

Objective: An effort currently made to appraise the preliminary phytochemical, pharmacognostic criteria, antioxidant, GCMS and antihyperglycemic investigations of the Thunbergia coccinea leaves. Thunbergia coccinea (T. coccinea) is an ornamental plant considerably practiced by the tribes of forest areas of Assam (INDIA) as an analgesic, antipyretic, anti-inflammatory, antidote, hepatoprotective, antidiabetic and detoxificant substance. Methods: A comprehensive literature survey was conducted to recognize the ethnomedicinal value of T. coccinea, which is currently grown practically in all provinces. The physicochemical constants like moisture content, ash values especially total ash, insoluble acid ash, water-soluble ash and foreign organic matter were determined for the assessment of the drug. Pharmacognostic parameters like fluorescence examination and microscopic characters of the leaf were studied that would serve to verify for contamination. The extract secured by maceration was subjected to the phytochemical inquiry to determine the existence of substances and their antioxidant activity. The antihyperglycemic characteristic of alcoholic extract of the leaf was examined with the inhibition of α-amylase and α-glucosidase enzymes. Gas Chromatography-Mass Spectrometry (GCMS) studies of alcoholic extract of the plant leaf have undertaken to get an insight into the therapeutic properties of the molecules present based on online PASS prediction. Results: Various physicochemical, microscopic parameters studied gave a clear distinguishing and identifying features of T. coccinea leaf. Phytochemical screening gave an insight into the secondary metabolites existing in the plant leaf through picturizing its therapeutic properties against various ailments. Both extracts of T. coccinea leaf showed enhanced antioxidant activities. Nevertheless, the alcoholic leaf extract has shown significant antioxidant activity with an IC50 of 171.38±2.51 μg/ml and AQTC an IC50 value of 206.29±4.5 μg/ml respectively by DPPH method. Further, ACTC showed a better-reducing potential with an IC50 value of 105.74±0.61 μg/ml in comparison with AQTC IC50 value of 203.702±0.97 μg/ml by FRP method. The inhibition potentiality of α-amylase and α-glucosidase was found to be 71.66 % and 83.74 %, respectively at 500 µg/ml that rationally an adequate remedy in the treatment of type-2 diabetes. GCMS studies of the alcoholic extract unveiled the presence of different molecules like Glycerol, tris (trimethylsilyl) ether, 3,7,11,15-Tetramethyl-2-hexadecen-1-ol, Undecanoic acid, Ethyl ester, Phytol in comparison with NIST library, thereby giving its predicted therapeutic properties like sugar phosphatase inhibitor, antifungal, phobic disorders treatment, antiviral and so on. Conclusion: The selected plant had many proven therapeutic traits and, possibly, successively united on to the sort of potential therapeutic plants. Besides, isolation and discoveries will lead to the detection of certain novel compounds, which will be of potential medicinal value.

In vitro antimicrobial and α-glucosidase inhibitory potential of enantiopure cycloalkylglycine derivatives: Insights into their in silico pharmacokinetic, druglikeness, and medicinal chemistry properties

The present investigation deals with the evaluation for the first time of the in vitro antimicrobial and α-glucosidaseinhibitory potential of a series of 15 enantiopure cycloalkylglycines using agar well diffusion and spectrophotometricmethods, respectively. The obtained results were compared to the positive controls. The antimicrobial results revealedthat all compounds exerted strongly inhibitory activity, especially against Gram-positive bacterial strains with the mostpotent activity was ascribed to α-γ-hydroxy-α-amino acids 11–14 [minimum inhibitory concentration (MIC) = 1.58–12.50 mg/ml, minimum bactericidal concentration (MBC) = 3.17–100 mg/ml, and minimum fungicidal concentration(MFC) = 6.25–50 mg/ml], followed by both isoxazolidine 5–9 (MIC = 1.58–12.50 mg/ml, MBC = 6.25–100 mg/ml,and MFC = 25–100 mg/ml) and isoxazine 10 (MIC = 3.17–12.50 mg/ml, MBC = 3.17–50 mg/ml, and MFC = 25–50mg/ml) compounds, and slightly inhibitory effect with α-amino-γ-lactones series 1–4 (MIC = 3.17–25 mg/ml, MBC =6.25–100 mg/ml, and MFC = 25–100 mg/ml). All the derivatives exhibited a potent α-glucosidase inhibitory activitywith compound 10 (IC50 = 30.1 ± 0.6 μM) was found to be the most active. The druglikeness and pharmacokineticprofiles have been also predicted. The in silico results indicate that all derivatives showed a resemblance with severalparameters of the antimicrobial standards, especially in terms of molecular property, bioavailability, lipophilicity,medicinal chemistry, and enzymatic inhibitory effects as well as they agree with the different drug discovery rules suchas Lipinski (Pfizer), Ghose (Amgen), Veber (GlaxoSmithKline), Egan (Pharmacia), and Muegge (Bayer) displaying ahigher druglikeness behavior.

New furo3,2-hisochroman from the mangrove endophytic fungus Aspergillus sp. 085242 / 中国天然药物

Four new compounds, asperisocoumarin G (1), asperisocoumarin H (2), (±)-asperisocoumarin I [(±)-3], along with the known pergillin (4) and penicisochroman L (5) were isolated from a mangrove endophytic fungus Aspergillus sp. 085242 by further chemical investigation. The structures of the new compounds, including their absolute configurations, were established by analysis of HR-ESI-MS and NMR spectroscopic data, and ECD calculation. Asperisocoumarins G-I (1-3) were new isocoumarins belonging to the class of furo[3, 2-h]isocoumarins which are rarely found in natural sources. All of the isolated compounds were evaluated for their α-glucosidase inhibitory effects, and compounds 1 and 4 showed moderate α-glucosidase inhibitory activity, respectively. In an antimicrobial test, the racemate of 3 showed antibacterial activity against Salmonella.

Novel carbohydrate-triazole derivatives as potential α-glucosidase inhibitors / 中国天然药物

A series of novel pyrano[2, 3-d]trizaole compounds were synthesized and their α-glucosidase inhibitory activities were evaluated by in vitro enzyme assay. The experimental data demonstrated that compound 10f showed up to 10-fold higher inhibition (IC74.0 ± 1.3 μmol·L) than acarbose. The molecular docking revealed that compound 10f could bind to α-glucosidase via the hydrophobic, π-π stacking, and hydrogen bonding interactions. The results may benefit further structural modifications to find new and potent α-glucosidase inhibitors.

Antidiabetic effect of Chrysophyllum albidum is mediated by enzyme inhibition and enhancement of glucose uptake via 3T3-L1 adipocytes and C2C12 myotubes

Objective: To investigate the in vivo and in vitro antidiabetic potential of Chrysophyllum albidum. Methods: The effects of oral treatment with hydro-ethanolic extract (125, 250 and 500 mg/kg) of the stem bark of Chrysophyllum albidum and glibenclamide for 21 d on glucose level, serum enzyme markers for liver function, lipid profile, total protein, serum urea, serum creatinine, and body weight were evaluated in experimental diabetic rats administered with 45 mg/kg of streptozotocin. In vitro assays including glucose uptake in C2C12 cells and 3T3-L1 adipose tissues, α-glucosidase and α-amylase inhibition were employed to evaluate the possible mechanism of hypoglycemic action of the extract. DPPH and nitric oxide radical antioxidant activity of the extract was also measured. Results: The increased levels of blood glucose, triglycerides, low-density lipoprotein, total cholesterol, serum aspartate, and alanine transaminases, creatinine, and urea in the diabetic animals were reduced significantly (P<0.01) after treatment with Chrysophyllum albidum extract. The decreased total protein and high-density lipoprotein concentrations were normalized after treatment. In addition, the extract significantly (P<0.01) increased the transport of glucose in 3T3-L1 cells and C2C12 myotubes and exhibited considerable potential to inhibit α-amylase and α-glucosidase. It also demonstrated potent antioxidant action by scavenging considerably DPPH and nitric oxide radicals. Conclusions: Chrysophyllum albidum stem bark extract exhibits considerable antidiabetic effect by stimulating glucose uptake and utilization in C2C12 myotubes and 3T3-L1 adipocytes as well as inhibiting the activities of α-amylase and α-glucosidase.

A new phenylpropanoid glycoside from leaves of Platycladus orientalis / 中草药

Objective: To study the chemical constituents from the leaves of Platycladus orientalis, as well as their antioxidant and α-glucosidase inhibitory activities. Methods: The compounds were isolated and purified by silica gel, MCI, polyamide, and prep-HPLC chromatography, their structures were elucidated by spectral analysis. DPPH and ABTS methods were used to study the antioxidant activity, and pNPG method was used to study the α-glucosidase inhibitory activity. Results: Eleven compounds (1-11) were isolated from the 80% ethanol extract of the leaves of P. orientalis, and identified as 4-O-(1’,3’-dihydroxypropan-2’-yl)- dihydroconiferyl alcohol 9-O-β-D-glucopyranoside (1), myricetrin (2), 5,8,3’,4’-tetrahydroxy-flavone-7-O-β-D-xylopyranoside (3), isomassonianoside B (4), (-)-isopramine 9’-O-β-D-glucopyranoside (5), (7R,8S,7’S,8’R)-4,9,4’,7’-tetrahydroxy-3,3’-dimethoxy- 7,9’-epoxylignan 4-O-β-D-glucopyranoside (6), sugiol (7), totarol (8), 5,6-dehydrosugiol methyl ether (9), isopimara-8,15-dien-7-one (10) and ethanol α-L-rhamnopyranoside (11). Conclusion: Compound 1 is a new compound, named as platycloside A; In the known compounds, seven compounds (4-7, 9-11) are isolated from this plant for the first time, six compounds (4-6, 9-11) are isolated from the family Thujoideae for the first time, and four compounds (5, 6, 10, 11) are isolated from the family Cupresaceae for the first time. The compounds 2-6 showed a degree of antioxidant activities. The compounds 2 and 3 showed the α-glucosidase inhibitory activities.

Triterpenoids from Gynostemma pentaphyllum and their inhibition activity to α-glycosidase and protein tyrosine phosphatase 1B / 中草药

Objective: To determine the total saponins from Gynostemma pentaphyllum, the dammarane-type triterpenoids of its hydrolysate, and its hypoglycemic activity. Methods: Compounds from the acid hydrolyzate extracts and total saponins were isolated by silica gel, recrystal and preparative liquid chromatography, and their structures were identified by the NMR spectral analysis. The sensitive screening modles of α-glucosidase and PTP1B inhibitors were established in vitro. The inhibitory kinetics of compounds were also investigated. Using the method of computer aided drug design of active site, PTP1B interact with the strongest active compound for docking simulation. Results: Seven compounds were isolated from the acid hydrolyzate of total saponins, which identified as gpsapogenin A (1), 20(S)-panaxadiol (2), gypensapogenin F (3), 20(R)-protopanaxadiol (4), (23S)-3β- hydroxydama-20,24-diene-21-carboxylic acid 21,23-lactone (5), gypsapogenin A (6), and (20S,24S)-3β,20,21β,23β,25- pentahydroxy-21,24-epoxydammarane (7). Five compounds were isolated from total saponins, including (20R,23R)- 3β,20-dihydroxydammar-24-en-21-oic acid 21,23-lactone 3-O-[α-L-rhamnopyranosyl(1→2)][β-D-xylopyranosyl(1→3)]-6-O- acetyl-β-D-glucopyranoside (8), (20S,23S)-3β,20-dihydroxydammar-24-en-21-oic acid 21,23-lactone 3-O-[α-L-rhamnopyranosyl(1→2)][β-D-xylopyranosyl(1→3)]-6-O-acetyl-β-D-glucopyranoside (9), (20R,23R)-19-oxo-3β,20-dihydroxydammar-24-en-21-oci acid 21,23-lactone3-O-[α-L-rhamnopyranosyl-(1→2)][β-D-xylopyranosyl(1→3)]-α-L-arabinopyranoside (10), (20S)-3β,20,21- trihydroxydammar-23,25-diene 3-O-{[α-L-rhamnopyranosyl(1→2)][β-D-xylopyranosyl(1→3)]-β-D-glucopyranosyl}-21-O-β- D-glucopyranoside (11), and (20S,23S)-3β,20-dihydroxydammar-24-en-21-oic acid and 21,23-lactone 3-O-[α-L-rhamnopyranosyl(1→2)][β-D-xylopyranosyl-(1→3)]-β-D-glucopyranoside (12). Conclusion: Beside compound 4, the other compounds showed inhibitory activity against α-glucosidase and PTP1B. For the α-glucosidase and PTP1B inhibitions assay, compound 9 indicated the strongest inhibitory effect with IC50 2.10 and 1.07 μmol/L, respectively.

New phenolic constituents obtained from Polygonum multiflorum / 中草药·英文版

Objective: To isolate the phenolic compounds obtained from the dried roots of Polygonum multiflorum and investigate their pharmacological activities. Methods: The chemical constituents were isolated and purified by combining them with a macroporous resin (DM-8), MCI gel, and Sephadex LH-20 and by performing ODS column chromatography. Their structures were elucidated by 1D and 2D NMR analyses, as well as mass spectrometry. The isolated compounds were evaluated to determine their hepatoprotective and α-glucosidase inhibitory activities in vitro. Results: Two phenolic compounds, namely, polygonimitin E (1) and polygonimitin F (2), were isolated from the dried roots of P. multiflorum. Compound 2 (10 µmol/L) only showed moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced HepG2 cell damage. Unfortunately, these two compounds exhibited no α-glucosidase inhibitory activity. Conclusion: Compounds 1 and 2 were new compounds. Compound 2 could be one of the potential hepatoprotective constituents of P. multiflorum.

Fingerprint Establishment ，Content Determination and α-glucosidase Inhibitory Activity Study of Polysaccharide from Desmodium styracifolium / 中国药房

OBJECTIVE：To estab lish the fingerprint ，analyze the monosaccharide composition and content ，investigate the inhibitory effects of the polysaccharide from Desmodium styracifolium on α-glucosidase in vitro . METHODS ：Polysaccharide from D. styracifolium was prepared by water extraction and ethanol precipitation. After hydrolyzed by TFA and derived by PMP ，HPLC method was adopted to establish the fingerprint （using glucose peak as reference ），and analyze the constituent and content of monosaccharide. The content determination was performed on Phenomenex Luna C 18 column with mobile phase consisted of acetonitrile-0.05 mol/L potassium phosphate （pH adjusted to 6.8 with sodium hydroxide ）in gradient elution at the flow rate of 0.8 mL/min. The detection wavelength was set at 250 nm，and column temperature was set at 30 ℃. The sample size was 10 μL. Using acarbose as control ，PNPG assay was used to investigate the α-glucosidase inhibitory activity of polysaccharide from D. styracifolium. RESULTS ：There were 9 common peaks in HPLC fingerprints of 18 batches of samples ，and the similarity of 15 batches of samples was higher than 0.90. Totally 7 peaks were identified as mannose ，rhamnose，galacturonic acid ，glucose， galactose，xylose and arabinose. The contents of rhamnose ，galacturonic acid ，glucose，galactose and arabinose were 0.471-2.092， 1.379-8.919，2.560-35.679，1.194-6.905，0.566-4.158 mg/g，respectively. Based on rhamnose ，the molar ratios of the other four monosaccharides were 1.58-4.07，2.26-19.95，2.20-4.21 and 1.31-2.86，respectively. The inhibitory activity of polysaccharide from D. styracifolium on α-glucosidase increased with the increase of dose ，and the half inhibitory concentrations of it was 0.70 mg/mL， lower than 7.76 mg/mL of acarbose （positive control ）. CONCLUSIONS ：Glucose is the main component of D. styracifolium polysaccharide in different batches ，and the contents of monosaccharides are different. The polysaccharide from D. styracifolium have significant inhibitory activity on α-glucosidase，which is better than that of acarbose.

Antidiabetic effect of Chrysophyllum albidum is mediated by enzyme inhibition and enhancement of glucose uptake via 3T3-L1 adipocytes and C2C12 myotubes

Objective: To investigate the in vivo and in vitro antidiabetic potential of Chrysophyllum albidum. Methods: The effects of oral treatment with hydro-ethanolic extract (125, 250 and 500 mg/kg) of the stem bark of Chrysophyllum albidum and glibenclamide for 21 d on glucose level, serum enzyme markers for liver function, lipid profile, total protein, serum urea, serum creatinine, and body weight were evaluated in experimental diabetic rats administered with 45 mg/kg of streptozotocin. In vitro assays including glucose uptake in C2C12 cells and 3T3-L1 adipose tissues, α-glucosidase and α-amylase inhibition were employed to evaluate the possible mechanism of hypoglycemic action of the extract. DPPH and nitric oxide radical antioxidant activity of the extract was also measured. Results: The increased levels of blood glucose, triglycerides, low-density lipoprotein, total cholesterol, serum aspartate, and alanine transaminases, creatinine, and urea in the diabetic animals were reduced significantly (P<0.01) after treatment with Chrysophyllum albidum extract. The decreased total protein and high-density lipoprotein concentrations were normalized after treatment. In addition, the extract significantly (P<0.01) increased the transport of glucose in 3T3-L1 cells and C2C12 myotubes and exhibited considerable potential to inhibit α-amylase and α-glucosidase. It also demonstrated potent antioxidant action by scavenging considerably DPPH and nitric oxide radicals. Conclusions: Chrysophyllum albidum stem bark extract exhibits considerable antidiabetic effect by stimulating glucose uptake and utilization in C2C12 myotubes and 3T3-L1 adipocytes as well as inhibiting the activities of α-amylase and α-glucosidase.

Phytochemical Composition, In Vitro Studies On Α-Amylase And Α-Glucosidase Inhibitory Activity Of Selected Mangrove Plants

The purpose of this study is to show the phytochemical composition and in vitro antidiabetic potential in the leaves of Ceriops tagal, Bruguiera cylindrica, and Salvadora persica mangrove plants. The phytochemical composition was studied by qualitative analysis. To determine in vitro antidiabetic activity leaves were subjected to solvent extraction by the Soxhlet method using methanol, ethanol, ethyl acetate, and pet ether and α-amylase, α-glucosidase inhibition assays were performed. The findings indicates that alkaloid, steroid, flavonoid, terpenoid, glycosides, tannin, saponin, phenol, quinones and coumarin principles are present in the leaves of selected mangrove species. Among the selected mangrove species C. tagal leaves recorded the highest antidiabetic activity for both the assay followed by B. cylidrica and S. persica. Overall C. tagal was found highly potent in the antidiabetic activity.

Characterization of ethyl acetate and methanol extracts of Commiphora myrrha and evaluating in vitro anti-diabetic and anti-obesity activities

Diabetes mellitus is a clinical disease categorized by hyperglycemia. Reduction of gastrointestinal glucose absorptionthrough the inhibition of carbohydrate digesting enzymes is one of in vitro anti-diabetic therapeutic approach. Thisinvestigation aimed to estimate the in vitro anti-diabetic and anti-obesity activities for ethyl acetate and methanolextracts of Commiphora myrrha oleo-gum as well as the identification of the bioactive compounds. Commiphoramyrrha was extracted with methanol and ethyl acetate. The two extracts were used to evaluate their α-glucosidase,α-amylase, and pancreatic lipase inhibitory activities. Identification of the bioactive compounds of ethyl acetate wasanalyzed by GC-MS (gas chromatography-mass spectrometry). The results showed that the ethyl acetate extract hada stronger inhibition activity on α-amylase (IC50 = 54.60 µg/ml) and α-glucosidase (IC50 = 58.7 µg/ml) than methanolextract on α-amylase (IC50 = 124.01 µg/ml) and α-glucosidase (IC50 = 191.2 µg/ml). Also, ethyl acetate extract hada promising inhibitory effect on pancreatic lipase (IC50 = 107.8 µg/ml) than methanol extract (IC50 = 498.1 µg/ml).GC-MS analysis of ethyl acetate extract identified 31 compounds. Among them nobiletin (50.26%), metaproterenol(orciprenaline) (14.99%), morantel (8.86%), and tricetin (3.38%) were the main compounds. These findings provedthat C. myrrha has anti-diabetic and anti-obesity inhibition activity may be due to the bioactive compounds withinteresting medicinal properties.

Isolation of flavonol rhamnosides from Pometia pinnata leaves and investigation of α-glucosidase inhibitory activity of flavonol derivatives

Pometia pinnata belonging to the Sapindaceae family has been traditionally used as the therapeutic agent for burns andwounds in Indonesia. Based on the result of the experiment conducted, the ethyl acetate fraction of P. pinnata leavesshowed strong α-glucosidase inhibitory activity. After two flavonol rhamnoside compounds were isolated from ethylacetate fraction of P. pinnata leaves methanol extract using chromatography method, their structures were identifiedas kaempferol-3-O-rhamnoside (1) and quercetin-3-O-rhamnoside (2). The ultra-performance liquid chromatographyelectrospray ionization time-of-flight mass spectrometry (UPLC-ESI-TOFMS) chromatogram showed compounds1 and 2 were the major compounds of the ethyl acetate fraction. In this study, the structure–activity relationshipamong the kaempferol, quercetin, and their derivatives bearing sugar moiety were also evaluated. Among tested eightcompounds, kaempferol 7 (percent inhibition = 80.10% ± 0.8) and quercetin 8 (percent inhibition = 82.93% ± 0.4) hadstronger α-glucosidase inhibitory activity than that of other derivatives. Among kaempferol derivatives bearing sugarmoiety, compound 1 showed the strongest activity. Moreover, compound 2 showed strong α-glucosidase inhibitoryactivity among quercetin derivatives. Therefore, it can be confirmed that the hydroxyl group at C-3 position is veryimportant for α-glucosidase inhibitory activity of flavonol compounds.