• YAKHAK HOEJI
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• v.54 no.5
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• pp.398-402
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• 2010

[ ${\alpha}$ ]Glucosidase inhibitor is a target in the treatment of type II diabetes through the mainly inhibition of glucose levels after meals. In this study, we purified steppogenin and oxyresveratrol from the stem of Morus alba L. and examined their inhibitory activity against yeast ${\alpha}$-glucosidase. Steppogenin and oxyresveratrol were inhibited yeast ${\alpha}$-glucosidase in a dose dependent manner. The $IC_{50}$ activities (50% inhibition) were 34.4 and 9.3 ${\mu}M$, respectively. The kinetic inhibition of steppogenin showed noncompetitive inhibition ($K_m:1.1{\times}10^{-3}M$; $K_i:1{\times}10^{-5}M$), meanwhile oxyresveratrol showed competitive inhibition ($K_m:4.3{\times}10^{-3}M$; $K_i:3.4{\times}10^{-6}M$) against yeast ${\alpha}$-glucosidase. These results indicate that steppogenin and oxyresveratrol are noncompetitive and competitive inhibitors, respectively, against yeast ${\alpha}$-glucosidase.

• Microbiology and Biotechnology Letters
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• v.18 no.1
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• pp.39-43
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• 1990

The inhibitor had the inhibitory activities against hydrolysis of PNPG, sucrose and ONPG by $\alpha$-Dglucosidase, $\alpha$ - and $\beta$ -galactosidase, but it did not inhibit amylases and other carbohydrases. Kinetic studies exhibited that the inhibitory substance non-competitively inhibited the enzyme reaction with a Ki value of 118 $\mu$g/m$\ell$, and enzyme-inhibitor complex was formed slowly.

• Korean Journal of Plant Resources
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• v.26 no.4
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• pp.411-416
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• 2013

This study was conducted not only to analyze ${\alpha}$-glucosidase inhibition activity with fronds and rhizomes of nine Pteridophyte species, but also to select the plant materials suitable for natural ${\alpha}$-glucosidase inhibitor. Harvested rhizomes and fronds were washed, freeze-dried and grinded. After conducting ultrasonification extraction for 30 minutes in ultrasonic water tank with 100% methanol solvent, and vacuum filtration, ${\alpha}$-glucosidase inhibition activity was measured. Acarbose was used as the positive control. After mixing $100{\mu}L$ of 0.7 unit ${\alpha}$-glucosidase enzyme solution into $50{\mu}L$ of extract and reacting them at $37^{\circ}C$ for 10 minutes, $50{\mu}L$ of 1.5 mM ${\rho}$-NPG solution was taken and reacted at $37^{\circ}C$ for 20 minutes. The reaction was stopped with 1 mL of 1 M $Na_2CO_3$ and absorbance was measured in 405 nm. With the regression analysis, the content of solubility solids (the value of $IC_{50}$) which can inhibit 50% of 0.7 unit ${\alpha}$-glucosidase solution's activity was investigated. The frond ($IC_{50}=14.00{\sim}913.33{\mu}g{\cdot}mL^{-1}$) and rhizome extracts ($IC_{50}=12.93{\sim}205.84{\mu}g{\cdot}mL^{-1}$) of nine Pteridophyte species showed higher ${\alpha}$-glucosidase inhibition activity in comparison with acarbose ($IC_{50}=1413.70{\mu}g{\cdot}mL^{-1}$). The extracts of fronds and rhizomes showed higher value than acarbose by 1.55~100.98 and 6.87~109.33 times each. Especially, ${\alpha}$-glucosidase inhibition activities of Pyrrosia lingua in fronds and Osmunda cinnamomea var. fokiensis in rhizomes were the highest. The necessary biomass of fronds and rhizomes for inhibiting 50% of ${\alpha}$-glucosidase activity showed the lowest value, 0.35, 0.27 mg each, in O. cinnamomea var. fokiensis. $IC_{50}$ value of P. lingua was the highest among fronds of nine Pteridophyte species, but content of soluble solids was 2.4 times less than O. cinnamomea var. fokiensis. So frond of O. cinnamomea var. fokiensis is more economic in comparison with P. lingua. As the result of this study, O. cinnamomea var. fokiensis showed high ${\alpha}$-glucosidase inhibition activity even with small biomass. Therefore it was considered to be high-valued economic material as natural ${\alpha}$-glucosidase inhibitor.

• Natural Product Sciences
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• v.10 no.5
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• pp.223-227
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• 2004

This study was carried out to investigate inhibitory effect of extracts from the root of Paeonia lactiflora on postprandial hyperglycemia. Organic solvent (hexane, ethyl acetate, butanol, aqueous) extracts from the crude drug were fractionated by high performance liquid chromatography. These fractions were examined to evaluate ${\alpha}-glucosidase$ (EC 3. 2. 1. 20) inhibition by microplate colorimetric assay. Among the fractions examined, the ethyl acetate fraction from the roots of Paeonia lactiflora showed potent inhibitory effects on ${\alpha}-glucosidase$. Therefore, further fractionation of the fraction was carried out to isolate the active principles. Finally, we isolated and Purified 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) as a active principle by activity-guided fractionation. These results suggest that the extract from the root of Paeonia lactiflora can be used as a new nutraceutial for inhibition on postprandial hyperglycemia and PGG might be a candidate for developing an ${\alpha}-glucosidase$ inhibitor.

• Nutrition Research and Practice
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• v.8 no.5
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• pp.602-606
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• 2014

BACKGROUND/OBJECTIVES: We investigated total 26 ingredients of Saengshik which will be commercially produced as an anti-diabetic dietary supplement. SUBJECTS/METHODS: Thirteen vegetables, nine cereals, three legumes and one seed were extracted with aqueous ethanol for 2 h at $60^{\circ}C$, and evaluated for their inhibitory effects against ${\alpha}$-amylase and ${\alpha}$-glucosidase and for total phenolic and flavonoid contents. RESULTS: All ingredients inhibited ${\alpha}$-amylase activity except cabbage. Strong inhibitory activity of ${\alpha}$-amylase was observed in leek, black rice, angelica and barley compared with acarbose as a positive control. Stronger inhibition of ${\alpha}$-glucosidase activity was found in small water dropwort, radish leaves, sorghum and cabbage than acarbose. All Saengshik ingredients suppressed ${\alpha}$-glucosidase activity in the range of 0.3-60.5%. Most ingredients contained total phenols which were in the range of 1.2-229.4 mg gallic acid equivalent/g dried extract. But, total phenolic contents were not observed in carrot, pumpkin and radish. All ingredients contained flavonoid in the range of 11.6-380.7 mg catechin equivalent/g dried extract. CONCLUSIONS: Our results demonstrate that Saengshik containing these ingredients would be an effective dietary supplement for diabetes.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.271-275
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• 2004

Distylium racemosum Sieb. Et Zucc contains some compounds inhibit -amylase activity in experimental conditions. The inhibitory test showed that 50% acetone extracts from the bark and leaves of the plant strongly inhibited salivary -amylase activity. Proanthocyanidin(PA) which has strong inhibitory activity was extracted from the leaves by chromatography on Sephadex LH-20. The inhibitory activities and the inhibition kinetics of the PA were studied against three kinds of enzymes: human salivary ${\alpha}-Amylase$ (SAA), pork pancreatin ${\alpha}-Amylase$ (PAA) and yeast ${\alpha}-Glucosidase$ (AG). Then the activities of PA against SAA, PAA and AG were compared with those of acarbose, a commercial agent. The inhibitory activities of PA were stronger than those of acarbose. Inhibition kinetics of the PA showed competitive inhibition for SAA and PAA, and non competitive inhibition for GA.

• Journal of Microbiology
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• v.42 no.3
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• pp.223-227
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• 2004

An ${\alpha}$-glucosidase inhibitor, SKG-3, was isolated from the fruiting bodies of Ganoderma lucidum and its physico-chemical properties were characterized. It was a highly specific and effective reversible inhibitor of ${\alpha}$-glucosidase. It showed very potent inhibitory activity against a-glucosidase with an IC$\sub$50/ value of 4.6$\mu\textrm{g}$/$m\ell$, but no activity for any other glycosidases tested. Enzyme activity could be recovered upon dialysis, thus providing evidence for the reversibility of the inhibition. A Lineweaver-Burk plot indicated that the SKG-3 inhibition of ${\alpha}$-glucosidase was competitive.

• Korean Journal of Pharmacognosy
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• v.40 no.3
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• pp.229-232
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• 2009

The ethanol (EtOH) extract of the branches of Cotinus coggygria (Anacardiaceae) exhibited a significant inhibition on the yeast $\alpha$-glucosidase, one of the key enzymes related with diabetes mellitus, in a dose dependent manner, in vitro. The intensive phytochemical survey of the EtOH extract of the species by way of bioactivity-guided fractionation resulted in the isolation of 1,2,3,4,6-penta-O-galloyl-$\beta$-D-glucose (1) as an active principle responsible for the inhibition on $\alpha$-glucosidase, together with two related components 2 and 3. Compound 1 demonstrated a strong inhibition on the yeast $\alpha$-glucosidase, in vitro and $IC_{50}$ value was calculated as 0.96 mg/ml, when that of a reference drug, acarbose was estimated as 5.3 mg/ml. On the other hand, other related constituents of the species, 1,2,3,6-tetra-O-galloyl-$\beta$-D-glucose (2) and gallic acid (3) were exhibited relatively poor inhibition upon the yeast $\alpha$-glucosidase, respectively.

• International Journal of Industrial Entomology and Biomaterials
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• v.15 no.2
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• pp.161-164
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• 2007

While searching for ${\alpha}$-glucosidase inhibitors, the active compound was found in a methanol extract of Burthus martensi Kirsch. The separation of the active compound was performed using various chromatography methods and the physico-chemical properties of the purified compound were characterized. The compound showed very potent inhibitory activity against ${\alpha}-glucosidase$ with an $IC_{50}$ value of $5.3\;{\mu}g/ml$. Lineweaver-Burk plot indicated that its inhibition of ${\alpha}-glucosidase$ was competitive.

• Journal of the Korean Wood Science and Technology
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• v.43 no.2
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• pp.238-247
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• 2015

Katsura tree (Cercidiphyllum japonicum Sieb. Et Zucc) leaves were collected, air-dried and extracted with 70% aqueous acetone, then concentrated and sequentially fractionated using n-hexane, $CH_2Cl_2$, EtOAc, and $H_2O$ to be freeze dried for antioxidant and ${\alpha}$-glucosidase inhibition activity tests. The antioxidant activity of the extracts was evaluated using DPPH (1,1-diphenyl 2-picrylhydrazyl) free radical scavenging assay. The test concentrations were adjusted to 500, 250, 125, 62.5, 31.25, 15.62, 7.81, 3.9, 1.95 and 0.97 ppm. The $H_2O$ and EtOAc fractions showed higher activities compared with the control, ${\alpha}$-tocopherol, at all concentrations. The crude fraction also gave better activity at the concentrations lower than 62.5 ppm. However, the nonpolar n-hexane and $CH_2Cl_2$ fractions gave prominently lower activities compared with the control at all concentrations. The $IC_{50}$ values of the crude, EtOAc, and $H_2O$ fractions exhibited 11.78, 4.29 and $9.80{\mu}g/m{\ell}$, respectively, compared with $12.08{\mu}g/m{\ell}$ of the control. But the n-hexane and $CH_2Cl_2$ fractions indicated 300 and $91.85{\mu}g/m{\ell}$ of $IC_{50}$, respectively. ${\alpha}$-Glucosidase inhibition activity was evaluated at the concentrations of 50, 25, 12.5, 6.3, 3.1, 1.6 and 0.8 ppm. The inhibition activities were increased according to as the increase of sample concentrations. However, the nonpolar n-hexane and $CH_2Cl_2$ fractions indicated very low inhibition activities compared with acarbose, a positive control. The EtOAc fraction showed very good capability as almost 100% compared with the control at the higher concentrations than 12.5 ppm and the crude fraction also indicated good potential as 95% and 100% at 25 and 50 ppm, respectively. The $H_2O$ fraction gave good inhibition value as 90% at 50 ppm although the value was lower than the control. These results showed that the polar fractions had better ${\alpha}$-glucosidase inhibition activities. The $IC_{50}$ values of the nonpolar fractions, n-hexane and $CH_2Cl_2$, showed very lower values as 468 and $103.6{\mu}g/m{\ell}$, respectively, than the control. ${\alpha}$-Glucosidase Inhibition Activity of the Extracts of Katsura Tree (Cercidiphyllum japonicum Sieb. Et Zucc) Leaves However, the polar fractions, crude, EtOAc and $H_2O$, showed 7.1, 3.7 and $13{\mu}g/m{\ell}$, respectively, indicating that these fractions can be used as natural bioresources for treating diabetes mellitus. Also ${\alpha}$-glucosidase inhibition activity had a positive correlation with antioxidant activity of the extracts.