• 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 Medicinal Crop Science
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• v.22 no.4
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• pp.289-294
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• 2014

Maesa japonica (Thunb.) is an evergreen shrub belonged to the Myrsinaceae family, which was discovered in 2006 in South Korea. And, its biological functions have not been well studied. In this study, we determined the antioxidant activities, ${\alpha}$-glucosidase inhibitory effects and antimicrobial activities of methanol extract and the solvent fractions of M. japonica leaves and twigs. The highest antioxidant activity obtained by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay and reducing power assay was found in the ethylacetate fraction of twigs methanol extract, which contained the highest level of total phenolic compounds compared to the other fractions. In addition, ethylacetate fraction of twigs extract exhibited higher inhibitory activities against ${\alpha}$-glucosidase ($IC_{50}=0.8{\mu}g/m{\ell}$) compared to the $IC_{50}$ of the buthanol fraction ($IC_{50}=16{\mu}g/m{\ell}$) of leaves extract. It showed antimicrobial activities against Bacillus atrophaeus and Bacillus subtilis subsp. Spizizenii. Although the data is too limited, the current study is the first report on biological functions of M. japonica.

• The Korean Journal of Food And Nutrition
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• v.34 no.3
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• pp.289-294
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• 2021

The antioxidant activity and α-glucosidase inhibitory activity of the solvent fraction fractionated from the methanol extract of Saururus chinensis Baill were examined. As a result of measuring the yields of methanol, hexane, chloroform, ethylacetate, butanol, and water fractions, the extraction yield of fraction was 18.60, 3.38, 24.03, 7.75, 8.11 and 62.57%, respectively. The total polyphenol content of the methanol extract of Saururus chinensis Baill was 13.40, 4.62, 7.39, 31.24, 25.76 and 5.64 mg GAE/g, respectively. DPPH radical scavenging activity (IC_50%) results were 20.81, 5.47, 10.15, 22.63, 19.68 and 21.06 ug/mL, respectively, and hydroxyl radical scavenging activity (IC_50%) results were 15.81, 2.69, 8.84, 12.80, 3.70 and 3.39 ug/mL. Hydrogen peroxide scavenging activity scavenging activity measurement (IC_50%) showed 33.63, 8.88, 16.93, 32.84, 33.79, and 33.71 ug/mL in methanol, hexane, chloroform, ethyl acetate butanol, and water fractions, respectively. The α-glucosidase inhibitory activity of the solvent fraction fractionated with the methanol extract of 300 sec was measured for the α-glucosidase inhibitory activity of methanol, hexane, chloroform, ethyl acetate butanol, and water fraction, respectively, 15.85, 10.84, 15.74, 24.90, 2.58 and 35.70%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.12
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• pp.1858-1864
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• 2014

In the present investigation, the anti-diabetic potential of 80% ethanol extract of Eleutherococcus senticosus leaves (EEES) was examined based on ${\alpha}$-glucosidase inhibitory activities. EEES was sequentially fractionated with n-hexane, chloroform, ethyl acetate (EtAOc), n-butanol, and $H_2O$. Of the various fractions, EtAOc fraction effectively inhibited ${\alpha}$-glucosidase activity by 68.05%. Therefore, EtAOc fraction was selected for further isolation and identification studies. EtAOc fraction was separated by medium pressure liquid chromatography with silica and ODS gel to yield eight fractions (EAA~EAH). Based on the results of ${\alpha}$-glucosidase inhibitory activity, EAH fraction was re-chromatographed to yielded four more fractions (EAHA~EAHD). Of these, EAHC fraction showed higher ${\alpha}$-glucosidase inhibitory activity of 93.60%. EAHC fraction was re-chromatographed and yielded EAHCA and EAHCB fractions. Further, identification and chemical structures of these two fractions were analyzed using $^1H$-NMR, $^{13}C$-NMR, and mass spectra data. Based on the results of the spectral data, the isolated compounds were identified as hyperoside and isoquercetin. Results of the present study indicate that the isolated compounds, hyperoside, and isoquercetin from leaves of E. senticosus could be used for the development of new anti-diabetic drugs.

• KSBB Journal
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• v.23 no.5
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• pp.419-424
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• 2008

In this study, we examined the anti-diabetic activity in vitro by the crude extracts of Tetragonia tetragonioides which has been known to superior plants for the traditional prevention and treatment of stomach-related diseases. $\alpha$-Amylase and $\alpha$-glucosidase, the principal enzymes involved in the metabolism of carbohydrates, and aldose reductase, the key enzyme of the polyol pathway, have been shown to play the important roles in the complications associated with diabetes. A hexane (HX) fraction of T. tetragonioides were shown to inhibit more than 50% of salivary and pancreatin $\alpha$-amylase activity at concentration of 2.882 mg/mL and 2.043 mg/mL, respectively. In addition, the HX and ethylacetate (EA) fraction showed the highest inhibitory activity on yeast $\alpha$-glucosidase at values of $IC_{50}$ of 0.723 mg/mL and 1.356 mg/mL respectively. The HX, dichloromethane (DCM) and EA fraction showed more higher inhibitory activity on yeast $\alpha$-glucosidase than commercial agent such as 1-deoxynorjirimycin and acarbose. Also, the aldose reductase from human muscle cell had been inhibited strongly by the DCM fraction and HX fraction at 51.95% and 47.22% at a concentration of 1 mg/mL, respectively. Our study, for the first time, revealed the anti-diabetic potential of T. tetragonioides and this study could be used to develop medicinal preparations or nutraceutical and functional foods for diabetes and related symptoms.

• Preventive Nutrition and Food Science
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• v.19 no.1
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• pp.5-9
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• 2014

This study was designed to investigate the inhibitory effects of Polyopes lancifolia extract (PLE) on ${\alpha}$-glucosidase activity, ${\alpha}$-amylase activitiy, and postprandial hyperglycemia in streptozotocin (STZ)-induced diabetic mice. The results of this study revealed a marked inhibitory effect of PLE on ${\alpha}$-glucosidase and ${\alpha}$-amylase activities. The $IC_{50}s$ of PLE against ${\alpha}$-glucosidase and ${\alpha}$-amylase were 0.20 mg/mL and 0.35 mg/mL, respectively. PLE was a more effective inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase activities than acarbose, the positive control. The postprandial blood glucose levels of STZ-induced diabetic mice were significantly lower in the PLE treated group than in the control group. Moreover, PLE administration was associated with a decreased area under the curve for the glucose response in diabetic mice. These results indicate that PLE may be a potent inhibitor of ${\alpha}$-glucosidase and ${\alpha}$-amylase activities and may suppress postprandial hyperglycemia.

• Food Science and Preservation
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• v.24 no.6
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• pp.879-884
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• 2017

In a continuing screening of selected medicinal plants native to Mongolia, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of methanol extract of Iris bungei were investigated. After extraction with 80% of methanol, the methanol fraction was further extracted with n-hexane, EtOAc and n-BuOH in order to obtain four different solvent-soluble fractions, namely n-hexane-soluble, EtOAc-soluble, n-BuOH-soluble and $H_2O$ residue. The antioxidant properties were evaluated by radical scavenging assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radicals. The anti-diabetic efficacy of I. bungei extract was investigated by ${\alpha}$-glucosidase assay. All tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory activities. Among the tested extracts, the EtOAc-soluble fractions showed the greatest radical scavenging activity and ${\alpha}$-glucosidase inhibitory properties among other solvent-soluble fractions. This result suggested that there was a significant relationship between the total phenolic content and biological efficacy. Thus, I. bungei extract might be considered as a new potential source of natural antioxidant and as a ${\alpha}$-glucosidase inhibitory source. A more systematic investigation of this biomass sill be performed for further investigation of activity against antioxidative and anti-diabetic effects.

• Journal of Applied Biological Chemistry
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• v.49 no.3
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• pp.82-85
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• 2006

Eucommia ulmoides bark extracts by cold water, boiling water, 100% EtOH, 70% EtOH, 100% MeOH, 70% MeOH and $CHCl_3$ were assayed for their medicinal effects. The antioxidant activity of the extracts ranged from $IC_{50}$ 125.2 to $IC_{50}\;872.7{\mu}g/ml$ in the 1,1-diphenyl-2-picrylhydrazyl (DDPH) free radical-scavenging assay, and cold water extracts had the highest antioxidant activity. $CHCl_3$ extracts had the highest inhibitory effect on angiotensin I-converting enzyme (ACE) giving inhibition of up to 56.4% at a concentration of 1 mg/ml. Extracts in 100% EtOH had the greatest inhibitory effect on $\acute{a}-amylase$ activity ($IC_{50}=174.6{\mu}g/ml$), and 70% MeOH extracts had the greatest inhibitory effect on ${\alpha}-glucosidase$ activity ($IC_{50}=14.0{\mu}g/ml$). Taken together, these results provided the in vitro evidence on the ACE, amylase and glucosidase inhibitory actions of E. ulmoides bark that form the pharmacological basis for its antihypertensive and antidiabetic action.

• Korean Journal of Medicinal Crop Science
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• v.26 no.5
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• pp.382-390
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• 2018

Background: The plant Aster koraiensis has long been used as an ingredient in folk medicine. It has been reported that Aster koraiensis extract (AKE) prevents the progression of diabetes-induced retinopathy and nephropathy. However, although these beneficial effects of AKE on diabetes complications have been identified, the antidiabetic effects of AKE have not yet been completely investigated and quantified. In the present study, the glucose-lowering and antioxidant effects of aqueous and ethanolic AKEs were evaluated. Methods and Results: The glucose-lowering effects of aqueous and ethanolic (30%-, 50%-, and 80%-ethanol) AKEs were investigated via ${\alpha}$-glucosidase inhibitory assays. The mode of inhibition by AKEs on ${\alpha}$-glucosidase was identified through kinetic analysis. The total antioxidant capacity of each of the 4 AKEs was evaluated by assessing their conversion rate of $Cu^{2+}$ to $Cu^+$. The content of chlorogenic acid and 3,5-di-O-caffeoylquinic acid, the bioactive compounds in AKE, in each extract were analyzed by high performance liquid chromatography (HPLC). The AKEs showed potent ${\alpha}$-glucosidase inhibitory activity with mixed inhibition mode, and significant antioxidant capacity. Conclusions: These results of this study suggested that the AKEs tested had ${\alpha}$-glucosidase inhibitory and antioxidant effects. Among the extracts, the 80% ethanol extract showed the most significant ${\alpha}$-glucosidase inhibitory activity, with a half maximal inhibitory concentration ($IC_{50}$ value) of $1.65{\pm}0.36mg/m{\ell}$ and a half maximal effective concentration ($EC_{50}$ value) for its antioxidant activity of $0.42{\pm}0.10mg/m{\ell}$. It can therefore be used as a source of therapeutic agents to treat diabetes patients.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.12
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• pp.1672-1678
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• 2009

This study was carried out to investigate the total polyphenol, total flavonoid content, antioxidant activity, angiotensin I-converting enzyme (ACE) inhibitory activity, $\alpha$-glucosidase inhibitory activity, and antiproliferation activity of the citron seed. The citron seed were separated to hull and embryo, and extracted with n-hexane and 70% ethanol. Antioxidant activity of ethanol extract was higher than that of n-hexane extract. IC50 value for DPPH radical scavenging activity of ethanol extract of hull (CSE1) and embryo (CSE2) were 3.18 and 8.43 mg/mL, and those of total antioxidant activity were 19.96 and 11.28 mg AA eq/g, respectively. ACE inhibitory activity and $\alpha$-glucosidase inhibitory activity on CSE1 showed the highest values of 31.61 and 45.17%, respectively. Antiproliferation effects on the MCF7, HepG2, H460, HCT-116, and PC3 cell line showed the highest values of 14.09, 19.12, 12.29, 9.78, and 9.12% in extract concentration of 5 mg/mL, respectively. These results suggested that citron seed can be used for development of functional food material which have biological activities.