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

• Nutrition Research and Practice
• /
• v.8 no.5
• /
• pp.602-606
• /
• 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 Plant Resources
• /
• v.26 no.4
• /
• pp.411-416
• /
• 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.

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

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

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

• The Korea Journal of Herbology
• /
• v.21 no.4
• /
• pp.115-121
• /
• 2006

Objectives : For the purpose of developing new anti-HIV agents from natural sources, the extracts of Actinidia arguta were tested for their inhibitory effects on essential enzymes as the reverse transcriptase (RT), protease and ${\alpha}-\;glucosidase$. And we predicted inhibition activity of major compounds of Actinidia arguta using Quantitative Structure Activity Relationships (QSAR). Methods : In this assay the activity of HIV-1 reverse transcriptase is measured as the formation of a strand of copy-DNA (cDNA) using RNA as a template. The activity of HIV-1 protease is measured as the cleavage of an oligopeptide by HIV-1 protease. Results : In the anti-HIV-1 RT using Enzyme Linked Oligonucleotide Sorbent Assay (ELOSA) method, water extracts (100ug/ml) of stem and leaf showed strong activity of 93.9% and 91.9%, respectively. In the HIV-1 protease inhibition assay, aqueous stem extract inhibited the activity of the enzyme to cleave an oligopeptide, resembling one of the cleavage sites in the viral polyprotein which can only be processed by HIV-1 protease with 56.8%. In the ${\alpha}-glucosidase$ inhibition assay, aqueous stem extract showed activity of 73.1%. Conclusion : We found out this result, for these samples it is possible that the inhibition of the viral replication in vitro is due to the inhibition at least one of RT and ${\alpha}-glucosidase$. It would be of great interest to identify the compounds which are responsible for this inhibition, since all therapeutically useful agent up to date are RT, PR and ${\alpha}-glucosidase$ inhibitors.

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

• Korean Journal of Pharmacognosy
• /
• v.41 no.2
• /
• pp.130-135
• /
• 2010

This study was performed to the activity of antioxidant and anti-diabetic from Zanthoxylum schnifolium fruit. The Zanthoxylum schnifolium fruits were extracted with water, 100% methanol, 100% ethanol, 70% methanol and 70% ethanol. The activities of each extracts were measured by antioxidant tests, such as total phenolic contents, total flavonoid contents, hydroxyl radical activity, DPPH radical scavenging activity, reducing power and $\alpha$-glucosidase inhibition activity assay. The water extract represented the highest activity in the antioxidants properties in vitro, including hydroxyl radical activity, DPPH radical scavenging activity, reducing power. Furthermore, water extract also showed significantly high total phenolic contents but the 100% methanol extract showed high total flavonoid contents estimated as $196.48{\mu}g/mg$. The $IC_{50}$ values for $\alpha$-glucosidase inhibition activity of the 100% ethanol and 100% methanol extracts were $275.66{\mu}g/mg$ and $261.44{\mu}g/mg$. Our results indicated that the Zanthoxylum schnifolium fruit expected to be useful as antioxidants.

• Journal of Life Science
• /
• v.29 no.1
• /
• pp.69-75
• /
• 2019

Rosemary (Rosmarinus officinalis L.) is widely used as a food material. Although various physiological activities of rosemary have been reported, there have been no studies on the physiological activity of solvent extracts with different polarities. Rosemary extracts were obtained by extraction of dried powder using 0%, 25%, 50%, 70%, and 95% ethanol (EtOH) in distilled water, methanol, ethyl acetate, and hexane. As these ratios of EtOH are generally chosen by default and scarcely optimized, we investigated the impact of the composition of EtOH in distilled water on extract-related characteristics, such as DPPH free radical scavenging and ${\alpha}$-glucosidase inhibition, on the differentiation of 3T3-L1 adipocytes and inhibition of tyrosinase. Adipogenesis inhibition was highest at 70% EtOH. DPPH scavenging activity and inhibition of tyrosinase activity were reduced with 50% EtOH in water. However, inhibition of ${\alpha}$-glucosidase activity was higher in 50% EtOH in water. The best solvents in terms of DPPH scavenging activity, inhibition of tyrosinase and ${\alpha}$-glucosidase, and differentiation of adipocytes obtained with different concentrations of EtOH, although a lower similar activities were found with 50% ethanol. Considering the extraction solvents, a ratio of EtOH in water gives different content and constituents of compounds. These differences will give activities inhibition of adipogenesis, tyrosinase, ${\alpha}$-glucosidase activity, and DPPH scavenging activity.