• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1290-1294
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• 2006

Biflavonoid (1) showed no antimicrobial activity at a concentration of 150 ${\mu}$g/disc. However, the crude extract of Quintinia acutifolia Kirk inhibited the growth of Bacillus subtilis and the dermatophytic fungus Trichophyton mentagrophytes. 2',3'-Dihydroochanaflavone (1) showed some cytotoxicity with IC$_{50}$ value of 3.1 ${\mu}$g/mL against P388 murine lymphocytic leukemia cells (positive control: mitomycin C IC$_{50}$ 0.06 ${\mu}$g/mL). The structure was determined by Spectroscopic methods.

• Bulletin of the Korean Chemical Society
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• v.34 no.10
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• pp.3147-3149
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• 2013

• Bulletin of the Korean Chemical Society
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• v.29 no.8
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• pp.1479-1484
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• 2008

Protein tyrosine phosphatase (PTP) 1B is the superfamily of PTPs and a negative regulator of multiple receptor tyrosine kinases (RTKs). Inhibition of protein tyrosine phosphatase 1B (PTP1B) has been proposed as a strategy for the treatment of type 2 diabetes and obesity. Recently, it has been reported that amentoflavone, a biflavonoid extracted from Selaginella tamariscina, inhibited PTP1B. In the present study, docking model between amentoflavone and PTP1B was determined using automated docking study. Based on this docking model and the interactions between the known inhibitors and PTP1B, we determined multiple pharmacophore maps which consisted of five features, two hydrogen bonding acceptors, two hydrogen bonding donors, and one lipophilic. Using receptor-oriented pharmacophore-based in silico screening, we searched the biflavonoid database including 40 naturally occurring biflavonoids. From these results, it can be proposed that two biflavonoids, sumaflavone and tetrahydroamentoflavone can be potent allosteric inhibitors, and the linkage at 5',8''-position of two flavones and a hydroxyl group at 4'-position are the critical factors for their allosteric inhibition. This study will be helpful to understand the mechanism of allosteric inhibition of PTP1B by biflavonoids and give insights to develop potent inhibitors of PTP1B.

• Archives of Pharmacal Research
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• v.29 no.9
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• pp.746-751
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• 2006

Amentoflavone is a plant biflavonoid that was isolated from an ethyl acetate extract of the whole plant of Selaginella tamariscina (Beauv.) spring. 1D and 2D NMR spectroscopy including DEPT, HMQC, and HMBC were used to determine its structure. Amentoflavone exhibited potent antifungal activity against several pathogenic fungal strains but had a very low hemolytic effect on human erythrocytes. In particular, amentoflavone induced the accumulation of intracellular trehalose on C. albicans as a stress response to the drug, and disrupted the dimorphic transition that forms pseudo-hyphae during pathogenesis. In conclusion, amentoflavone has great potential to be a lead compound for the development of antifungal agents.

• Journal of the Korea Convergence Society
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• v.9 no.6
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• pp.89-98
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• 2018

To confirm the feasibility as raw materials for cosmetic formulation, ethanol, n-hexane, ethylacetate and normal butyl alcohol were extracted from 1kg of Ginko leaves. Ultimately, investigated chemical structure and physicochemical properties of ginkgetin and isoginkgetin. The purity of those two components have been evaluated higher than 99%. They are isomers with molecular weight as 566 and a molecular formular, $C_{32}H_{22}O_{10}$. Flavonoid's frame and NMR spectrum exhibited the existence of aromatic proton and the proper ratio of the carbon, which were expected structures exactly corresponded to the reported references.

• Korean Journal of Pharmacognosy
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• v.33 no.1 s.128
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• pp.49-52
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• 2002

Amentoflavone, naturally occurring biflavonoid, isolated from the leaves of Ginko biloba, selectively inhibited human seceretory phospholipase $A_2$. This compound potently and irreversibly inhibited human group IIA in a dose dependent manner with an $IC_50$ about $3\;{\mu}M$. Amentoflavone inhibited phospholipase $A_2$ by a noncompetitive manner with the apparent Ki value of $1{\times}10^{-5}M$. In addition, the inhibitory activity of amentoflavone is rather specific against group IIA phospholipase $A_2$ than group IB phospholipase $A_2$. Furthermore, this compound strong inhibit histamine release from $A_{23187}$ treated rat peritoneal mast cells. These results indicate naturally occurring biflavonoid represents a novel anti-inflammatory agent.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.57-57
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• 1995

1) 효소원의 조제 : 류마티스 관절염환자의 관절액 및 rat platelet PLA$_2$는 장등의 방법으로 조재하여 사용하였으며, 기질은 1-pal- (1-$^{14}$ C) linoleoyl PE로 하여 Dole 변법으로 효소활성을 측정하였다. 2) Histamine 유리반응 ; Rat복강으로부터 정제한 비만세포를 항원-항체 복합체로 자극하거나, $A_{23187}$등의 처리로 유리되는 histamine 을 methylation 시킨 후 유기용매법으로 추출한 후 scintillation counter로 측정하였다. 결과 : \circled1 천연물로부터 분리한 5종의 biflavonoid (amentoflavone 및 그 유도체)의 PLA$_2$ 저해 활성을 검토한 결과 거의 유사한 IC50 (약 3$\mu\textrm{m}$)을 나타내었다. \circled2 이들 중 amentoflavone은 염증성 PLA$_2$(Group II형 PLA$_2$)에 비교적 특이성을 나타내었다. 또한 제해양식은 비경쟁적 이면서 비가역적이였다. \circled3 비만세포에서 histamine 유리 억제반응은 자극제의 종류에 관계없이 억제작용을 나타내었으며, 기존에 임상적으로 사용되고 있는 Tranilast나 DSCG(disodium chromoglycate)에 비하여 10배 이상 강한 histamine 유리 억제작용을 나타내었다.다.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.56-56
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• 1995

자연계에 널리 분포하고 있는 flavonoid 유도체들은 다양한 구조에 따라, 다양한 생물활성을 보인다. 최근에는 이들이 cyclooxygenase/lipoxygenase를 저해한다는 사실이 알려진 후에 이들 유도체들을 항염증제 또는 항알레르기 약물로 개발하려는 시도가 계속되고 있다. 이들 연구의 일환으로 본 연구자들은 여러 flavonoid유도체들에 대한 in vivo 항염증능 및 림프구증식억제능을 보고하였다 (Arch. Pharm. Res. 16, 18, 25 (1993), 17, 31, 236 (1994), Life Sci. 54, 313 (1994)). 또한 flavonoid 유도체들 중 apigenin-dimer인 수종의 biflavonoid들이 group II phospholipase $A_2$ 저해제인 것을 밝혔고 (BBRC 205, 843 (1994)), 이들 중 몇 종은 림프구증식능에 대하여 억제작용을 보인다는 것을 알았다 (Life Sci. in revision). 본 연구에서는 이들 biflavonoid 유도체들 중 amentoflavone과 ginkgetin을 중심으로 이들의 림프구증식억제능 및 in vivo에서의 항염증작용을 연구하였다. 그 결과, ginkgetin (1-10 $\mu$M)은 Con A와 LPS에 의해 유도되는 림프구중식을 비가역적으로 억제하였으며, 이들 유도체들은 마우스 귀부종에 대하여 복강내투여에서 강력한 항염증능을 보인다는 것을 알았다.

• Archives of Pharmacal Research
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• v.21 no.4
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• pp.406-410
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• 1998

Biflavonoid is one of unique classes of naturally-occurring bioflavonoids. Certain biflavonoids including amentoflavone were previously reported to have inhibitory effect on the group 11 phospholipase $A_2$ activity. Amentoflavone was also found to inhibit cyclooxygenase from guinea-pig epidermis without affecting lipoxygenase. In this study, anti-inflammatory and analgesic activities of amentoflavone were evaluated. When amentoflavone was administered intraperitoneally, it showed a potent anti-inflammatory activity as determined by amelioration of croton-oil induced mouse ear edema. It also showed a potent anti-inflammatory activity in the rat carrageenan paw edema model ($ED_{50}$=42 mg/kg) compared to the activity of prednisolone (35 mg/kg) and indomethacin (10 mg/kg). However, amentoflavone did not show a significant inhibitory activity against rat adjuvant-induced arthritis, a chronic inflammatory model. In addition, amentoflavone was found to possess a potent analgesic activity in the acetic acid writhing test ($ED_{50}$=9.6 mg/kg) compared to the activity of indomethacin (3.8 mg/kg). These results suggest that amentoflavone may be a potential lead for a new type of anti-inflammatory agents having dual inhibitory activity of group 11 phospholipase $A_2$ and cyclooxygenase.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.05a
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• pp.41-42
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• 2003

Matrix metalloproteinases (MMPs) inhibitors were screened from Metasequoia glyptostroboides and one potent inhibitor, dihydrohinokiflavone (DHHF), a biflavonoid, was selected. DHHF inhibited proliferation of HT1080, human fibrosarcoma cells in a dose-dependent manner. Noncytotoxic levels of DHHF dramatically decreased MMP-9 and MMP-2 production in unistimulated cells, but did not change the level of tissue inhibited of metalloproteinase (TIMP)-1, an inhibitor of MMP-9.(omitted)