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

• Current Research on Agriculture and Life Sciences
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• v.31 no.4
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• pp.227-232
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• 2013

We studied antioxidant activity and inhibitory effect of ${\alpha}$-glucosidase from aqueous, ethanolic and methanolic fractions of Galla rhois. In FRAP and ORAC assay for measuring antioxidant activity, we confirmed that Galla rhois extracts had strong antioxidant activity and ethanolic and methanolic extracts were relatively stronger than aqueous extract. We used trolox as a positive control. In order to measure the inhibitory effect of ${\alpha}$-glucosidase, we compared acarbose and Galla rhois extracts. As a result of ${\alpha}$-glucosidase inhibitory assay, aqueous, ethanolic and methanolic extracts of Galla rhois showed high inhibitory activitity and ethanolic and methanolic extracts were relatively stronger than aqueous extract. The 50% inhibitory concentrations (IC50s) of acarbose, aqueous, ethanolic and methanolic fractions were 0.45 mM, $0.53{\mu}g/ml$, $0.415{\mu}g/ml$ and $0.37{\mu}g/ml$, respectively. These results suggest that Galla rhois extracts can be a clinically useful anti-diabetic ingredient, indicating that it needs to be fractionated and isolated and should be further investigated.

• Korean Journal of Oriental Medicine
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• v.10 no.1
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• pp.119-126
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• 2004

For the purpose of developing new anti-HIV agents from natural sources, the extracts of Solanum nigrum L. were tested for their inhibitory effects on HIV-1 replication and its essential enzymes as the reverse transcriptase (RT), protease and ${\alpha}$-glucosidase. In the assay of HIV-1-infected human T-cell line, water extracts inhibited the HIV- 1 -induced cytopathic effects with IC (inhibitory concentration) of 100 ug/ml. Moreover water extracts (100ug/ml) of aerial parts showed strong activity of 32.6% on anti-HIV-1 PR using the activity of the enzyme to cleave an oligopeptide. In the HIV-1 reverse transcriptase inhibition assay, aqueous extract a inhibited 17.4%, but no glucosidase inhibitory activities. 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 PR and RT. 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 PR, RT and ${\alpha}$-glucosidase inhibitors.

• Preventive Nutrition and Food Science
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• v.16 no.3
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• pp.236-241
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• 2011

Allium victorialis L. (A. victorialis) is a very popular vegetable in Korea. The most commonly used parts of this vegetable are the bulbs and young leaves. To determine if the mature leaves have any beneficial properties, we investigated antioxidant, anti-${\alpha}$-glucosidase, anti-inflammatory, and anticancer activities of water and ethanol extracts from A. victorialis. Antioxidant activity was evaluated by measuring total phenolic content, DPPH and superoxide radicals scavenging activities. The water extract from A. victorialis ($W{\cdot}A$. victorialis) exhibited higher antioxidant ability than the ethanol extract ($E{\cdot}A$. victorialis). Moreover, the water extract showed strong inhibitory effect on ${\alpha}$-glucosidase. On the other hand, the ethanol extract had greater anti-inflammatory activity on murine macrophage cells (RAW 264.7) and greater anticancer activities against human colon cancer cells (HT-29). These results suggest that mature leaves from E·A. victorialis may have health-enhancing effects.

• Preventive Nutrition and Food Science
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• v.16 no.1
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• pp.89-94
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• 2011

The potential biological activities of water and ethanol extracts from two varieties of Rubus coreanus Miquel fruits produced in the Gochang-gun (GR) and Hoengseong-gun (HR) regions of Korea were examined. The hydroxyl radical ($\cdot$OH) scavenging activity, reducing power, lipid peroxidation inhibitory activity, and antiproliferative activity on cancer cells by these extracts were examined, and $\alpha$-amylase and $\alpha$-glucosidase inhibition assays were also performed. The EtOH extract from GR showed high hydroxyl radical scavenging activity ($EC_{50}=119.47{\pm}5.13\;{\mu}g/mL$), lipid peroxidation inhibitory activity ($EC_{50}=213.45{\pm}3.14\;{\mu}g/mL$) and a concentration dependence, with OD values ranging from 0.15 to 0.56 (50 to 200 ${\mu}g/mL$), for reducing power. The EtOH extract from GR has the highest antiproliferative activities on MDA-MB-231 and HepG2 cancer cells among four extracts. Meanwhile, all extracts showed certain $\alpha$-amylase and $\alpha$-glucosidase inhibition activities. These results indicate that extracts from two varieties of R. coreanus fruits have significant antioxidant, anti-diabetic and anti-tumorigenic activities, which suggest these extracts could be a potential source for pharmaceutical.

• Food Science and Preservation
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• v.23 no.2
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• pp.239-245
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• 2016

This study was conducted to compare the functionality (antioxidant, anti-diabetic, and anti-dementia activities) of the methanol extract of Allium hookeri root grown in Korea (KR) and Myanmar (MR). The total polyphenol and flavonoid contents of KR and MR were 5.27 and 4.80 mg GAE/g, and 0.35 and 0.24 mg QE/g, respectively. KR contained significantly higher levels of total polyphenols and total flavonoids than those of MR (p<0.05). The IC50 values of KR and MR were 6.53 and 5.31 mg/mL, respectively, for DPPH radical scavenging activity. However, KR had a significantly higher ABTS radical scavenging activity, $Fe^{2+}$ chelating ability, and reducing power compared with those of MR (p<0.05). In the evaluation of anti-diabetic activity, KR showed significantly higher ${\alpha}-glucosidase$ inhibition activity than acarbose and MR at whole concentrations (p<0.05). KR and MR had acetylcholinesterase inhibition activities that of 51.44% and 44.33%, respectively, at a 50 mg/mL concentration. These results suggested that roots of A. hookeri, especially KR, could be useful in improving diabetic and dementia disorders due to their high antioxidant, anti-diabetic, and anti-dementia activities.

• 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.

• Journal of Life Science
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• v.24 no.9
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• pp.935-945
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• 2014

Persimmon leaves were commonly consumed as beverages, but were also used as popular folk medicine in Asia. The purpose of this work was to assess the biological activities of Diospyros Lotus L. extracts (DLLE). Various solvent extracts, including n-Hexnae, $CHCl_3$, EtOAc, and n-BuOH fractions, were obtained from the methanol extract of Diospyros Lotus L. leaves. The increasing interest in the powerful biological activity of plant phenolics and flavonoids outlined the necessity for determining their content in medicinal herbs. In this study, the total polyphenol and flavonoid contents (TPC and TFC) in the EA fraction were higher than those of other fractions. The biological activities of DLLE were tested using the 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity assay, as well as superoxide dismutase (SOD) activity as an anti-oxidant effect and ${\alpha}$-glucosidase inhibitory activity as an anti-diabetic effect. The EA fraction with high TPC and TFC values showed the highest anti-oxidant effect and high ${\alpha}$-glucosidase inhibition. The EA fractions were further purified into eight fractions using open column chromatography. Higher anti-oxidant and anti-${\alpha}$-glucosidase activity were observed in polar fractions. The content of the flavonoids, including quercein-3-O-rutinoside, kaempferol-3-O-glucoside, myricetin, luteolin, and kaempferol, were analyzed in effective fractions using high-performance liquid chromatography (HPLC). The results suggest that DLLE have anti-oxidative and anti-diabetic effects and thus, have the potential as anti-diabetic materials and as a source for natural health products.

• 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.

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