• Journal of Applied Biological Chemistry
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• v.65 no.1
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• pp.75-79
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• 2022

Antioxidant, α-glucosidase inhibition, and anticoagulant effects of 80% ethanolic extract from mistletoe (Viscum album var. coloratum) were investigated. The yield and polyphenol content of the mistletoe extract were 30.9±0.4% and 57.6±1.5 mg gallic acid equivalents/g, respectively. The antioxidant effects of the mistletoe extract such as free and cationic radical scavenging ability, nitrite scavenging ability, and reducing power increased in proportion to its concentration. Also the mistletoe extract inhibited the activity of α-glucosidase, and delayed plasma coagulation mainly by inhibiting the extrinsic and common pathways in blood coagulation system.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.81-86
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• 2019

A yellow resin (gamboge) from Garcinia hanburyi has been widely used as folk medicine due to its antibacterial and antitumor activities. We isolated four ${\alpha}$-glucosidase inhibitory compounds from the methanol extract of gamboge. The compounds (1-4) were identified as gambogoic acid (1), moreollic acid (2), gambogic acid (3), and 10-methoxygambogenic acid (4), respectively through spectroscopic data including 2D-NMR and HREIMS. All compounds were examined in the enzyme inhibition assay against ${\alpha}$-glucosidase to identify their inhibitory potencies and kinetic behavior. All compounds (1-4) showed enzyme inhibition against ${\alpha}$-glucosidase, but the activity was significantly affected by the methoxy group on C-10 of ring A and pentenyl pyran moiety of ring D. For example, compound 1 ($IC_{50}=41.4{\mu}M$) bearing pyran ring eight times effective that 4 ($IC_{50}=350.6{\mu}M$) having geranyl group itself. Most active compound was found out to be gambogoic acid (1) which was analyzed most abundant metabolite in gamboge by LC-ESI-MS/MS. In kinetic study, compounds 1 and 2 were proved as noncompetitive inhibitors.

• Korean Journal of Plant Resources
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• v.23 no.5
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• pp.423-429
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• 2010

In this study, we examined the anti-diabetic activity in vitro by the mixed Korean herb water extracts(JDG) composed of Lycium chinense, Cordyceps militaris, and Acanthopanax senticosus on hepatic glucose-regulating enzyme activities such as glucokinase(GK), acetyl-CoA carboxylase(ACC), and inhibition activity of $\alpha$-glucosidase. The hepatic cytosol fraction of a type II diabetic animal(Goto-Kakizaki rat) was used in GK and ACC activity assays. JDG mixed water extracts significantly increased the hepatic GK and ACC activity. The highest anti-$\alpha$-glucosidase activity was observed in JDG 5 water extract when compared to the acarbose control, inhibitor of $\alpha$-glucosidase. We suggest that Lycium chinense, Cordyceps militaris, and Acanthopanax senticosus mixed water extracts may exert an anti-diabetic activity by enhancing the glucose metabolism and may be used as natural $\alpha$-glucosidase inhibitors in type 2 diabetic conditions.

• Journal of Nutrition and Health
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• v.46 no.4
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• pp.315-323
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• 2013

This study was conducted in order to compare the biological activities of leaf and root water extracts of Smilax china L. (SC) by measuring the total polyphenol and flavonoid contents, anti-oxidant activity, inhibitory effect on ${\alpha}$-glucosidase, and anti-inflammatory gene expression. The total polyphenol and flavonoid contents of SC leaf (SCLE) and root (SCRE) water extracts were 127.93 mg GAE/g and 39.50 mg GAE/g and 41.99 mg QE/g and 1.25 mg QE/g, respectively. The anti-oxidative activities of SCLE and SCRE were measured using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity assay and reducing power assay. Both SCLE and SCRE scavenged radicals in a concentration-dependent manner, and SCLE showed stronger radical scavenging activity and reducing power than SCRE; however, both SCLE and SCRE exhibited lower activities than ascorbic acid. Compared to the anti-diabetic drug acarbose, which was used as a positive control, SCLE and SCRE exhibited low ${\alpha}$-glucosidase inhibition activities; nevertheless, the activity of SCLE was 3.7 fold higher than that of SCRE. Finally, SCLE caused significantly decreased expression of the LPS-induced cytokines, iNOS, and COX-2 mRNA in RAW264.7 cells, indicating anti-inflammatory activity. These results indicate that SCLE might be a potential candidate as an anti-oxidant, anti-diabetic, and anti-inflammatory agent.

• Food Science and Preservation
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• v.18 no.4
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• pp.620-625
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• 2011

This is a part of the study on the food materials that are effective for diabetes treatment and for use in the development of functional bread products. In this study, various commercially available Oriental medicines with the intestinal absorption enzyme called ${\alpha}$-glucosidase, which is known to be effective for diabetes treatment, were explored. According to the research results on the water and methanol in 200 kinds of Oriental medicines, which were separated by layer to investigate the inhibitory activity of ${\alpha}$-glucosidase, Astragalus membranaceus (70.9%) in the water layer and Pericaeta communissima (72.9%) in the MeOH layer showed a strong inhibitory effect of over 70%. Myristica fragrans (69%), Morus alba (66.9%), Schisandra chinensis (65%), Panax notoginsens (63.9%), Anthriscus sylvestris (62.9%), Asparagus cochinchinensis (62.1%), Erycibe obtusifolia (60.9%), Polygonum cuspidatum (60.7%), Atractylodes lancea (60.2%), and Perilla frutescens (60.2%) in the water layer, and Codonopsis pilosula (67.8%), Prunus persica batsch (67.6%), Sinomenium acutum (63.5%), and Malvae semen (61.6%) in the MeOH layer, showed a more than 60% inhibitory effect. Thirty one species, including Polygonatum sibiricum (59.8%), Medicata fementata (59.7%), Alisma canaliculatum (59.5%), Coix lacryma-jobi (59.2%), Asiasarum sieboldi (59.0%), and Bupleurum falcatum (53.0%), in the water layer, and 10 species [Quisqualis indica (58.8%), Lycium chinense (58.3%), Trichosanthes kirilowii (58.0%), Thuja orientalis (55.9%), Bombyx mori (55.6%), Gallus domesticus (55.4%), Aralia continentalis (55.3%), Cibotium barometz (52.7%), Euphorbia pekinensis (52.7%), and Dolichos lablab (52.5%)] in the MeOHlayer, showed a more than 50% inhibitory effect. Therefore, such materials are expected to be the basic materials that will be used for the development of functional materials for diabetes treatment.

• 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.

• Food Science and Preservation
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• v.23 no.7
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• pp.989-994
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• 2016

As part of our continuing search for bioactive natural products, the antioxidant and ${\alpha}$-glucosidase inhibitory activities of an 80% methanolic extract and organic solvent soluble-portions of Aruncus dioicus var. kamtschaticus roots were investigated by using a bioassay system. The antioxidant activity of A. dioicus var. kamtschaticus roots extract and organic solvent soluble-portions were assessed by examining with 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) ($ABTS^+$) radical scavenging. In addition, anti-diabetic effects of the A. dioicus var. kamtschaticus root extract and organic solvent soluble-portions were tested via ${\alpha}$-glucosidase inhibition assay. The total phenolic contents of the products were determined by applying UV-VIS spectrophotometry. All tested samples showed dose-dependent radical scavenging and ${\alpha}$-glucosidase inhibitory properties. In particular, the ${\alpha}$-glucosidase inhibitory and radical scavenging effects of the ethyl-acetate (EtOAc)-soluble portion from the roots of A. dioicus var. kamtschaticus were greater than those from other solvent-soluble portions. These results indicate that A. dioicus var. kamtschaticus could be considered a new effective source of natural antioxidants and anti-diabetic materials. More systematic research of the constituents of the roots of this A. dioicus variety will be conducted to further develop its antioxidative and anti-diabetic properties.

• The Korean Journal of Community Living Science
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• v.18 no.3
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• pp.407-415
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• 2007

The aim of this study was to investigate the physiological functionalities of Codonopsis lanceolata, Glycyrrhiza uralensis, Chaenomeles sinensis, Crataegus pinnafida, and their mixtures. We also determined their antioxidative, fibrinolytic, and ${\alpha}-glucosidase$ inhibitory activities. The antioxidative activities of Codonopsis lanceolata, Glycyrrhiza uralensis, Chaenomeles sinensis, and Crataegus pinnafida were 79%, 88.3%, 89.9%, and 89.3% respectively. Their fibrinolytic activities were 0.80plasmin unit/mi, 0.57 plasmin unit/mi, 0.52 plasmin unit/mi, and 0.53 plasmin unit/mi respectively. The ${\alpha}-glucosidase$ inhibitory activity of Codonopsis lanceolata was 25%. The 10-fold diluents of Glycyrrhiza uralensis, Chaenomeles sinensis, and Crataegus pinnafida showed ${\alpha}-glucosidase$ inhibitory activities of 93.6%, 65.3%, and 61.3% respectively. In antioxidative activity tests of the medicinal plants mixtures at various ratios, the mixtures of Glycyrrhiza uralensis, Chaenomeles sinensis, and Crataegus pinnafida with Codonopsis lanceolata showed antioxidative activities of approximately 90%. In fibrinolytic activity tests mixtures(1:1) of Codonopsis lanceolata with Chaenomeles sinensis and Crataegus pinnafida exhibited increases of 23% and 24% in activity respectively. In ${\alpha}-glucosidase$ inhibitory activity tests, a mixture (4:1) of Codonopsis lanceolata and 10-fold diluted Glycyrrhiza uralensis showed an inhibitory activity of 98%, a mixture (3:1) of Codonopsis lanceolata and 10-fold diluted Chaenomeles sinensis showed an inhibitory activity of 69.6%, and a mixture (1:1) of Codonopsis lanceolata and 10-fold diluted Crataegus pinnafida showed an inhibitory activity of 50.2%. In conclusion, the mixtures of Glycyrrhiza uralensis, Chaenomeles sinensis, and Crataegus pinnafida with Codonopsis lanceolata will be used as a material for the development of biofunctional foods.

• Journal of Applied Biological Chemistry
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• v.43 no.3
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• pp.141-146
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• 2000

Glycosidase activities were tested from the grape berries, Vitis labruscana B. Takasumi. Among various glycosidases, $\alpha$-D-galactosidase was found to be the most active in the flesh and other glycosidases were considerably active in the order of the following: $\alpha$-D-mannosidase>$\alpha$-D-glucosidase>$\beta$-D-glucosidase>$\beta$-D-galactosidase. In the seeds, $\alpha$-D-glucosidase activity was the highest and other glycosidases such as $\alpha$-D-galactosidase, $\beta$-D-glucosidase, and $\beta$-D-galactosidase were still significantly active. The $\alpha$-D-galactosidase in the grape flesh was purified over 83-folds through salting-out with $(NH_4)_2SO_4$ and a series of chromatographies employing Sephadex G-50, Octyl-Sepharose, Q-Sepha- rose, and Biogel P-100. The enzyme was a monomer of 45 kDs as determined through SDS-PAGE and Sephacryl S-200 chromatography. The purified enzyme showed a preference of $\alpha$-D-galactose to $\beta$-D-galactose as a substrate about 5.4 times. Sulfhydryl specific reagents such as N-ethylmaleimide and iodoacetamide significantly inhibited the enzyme activity to the extents of 48 and 52% of its initial activity, respectively. The optimumpH range of $\alpha$-D-galactosidase was around 6.5-7.0. The enzyme activity increased by 46% in the presence of 1mM $Fe^{2+}$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.7
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• pp.1090-1099
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• 2015

Among the four different parts of mulberry (Morus alba L.) tree, ethanol extract of Morus root bark showed the highest ${\alpha}$-glucosidase inhibitory activity ($IC_{50}=12.01{\mu}g/mL$). Bioassay-guided fractionation of the ethanolic extract of root bark by Diaion HP-20, silica gel, ODS-A, and Sephadex LH-20 column chromatographies led to the isolation of four compounds, including Compound (Comp.) 1 ($IC_{50}=5.22{\mu}g/mL$), Comp. 2 ($IC_{50}=1.78{\mu}g/mL$), Comp. 3 ($IC_{50}=2.94{\mu}g/mL$), and Comp. 4 ($IC_{50}=1.54{\mu}g/mL$) with strong ${\alpha}$-glucosidase inhibitory activities. Their chemical structures were elucidated as morusin (Comp. 1), kuwanon H (Comp. 2), chalcomoracin A (Comp. 3), and chalcomoracin B (Comp. 4) by UV and NMR spectral analyses. These results suggest that prenylflavonoid and mulberrofuran of Morus root bark may be useful as potential therapeutic agents for diabetes.