• Proceedings of the Korean Society of Applied Pharmacology
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• 1998.11a
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• pp.195-195
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• 1998

Ginkgetin was previously reported as an inhibitor of group II phospholipase A$_2$. It also inhibited in vitro arachidonate release from the activated macrophages and lymphocyte proliferation. These previous studies suggested an anti-inflammatory nature of ginkgetin, especially on chronic inflammation. In fact, ginkgetin showed potent anti-inflammatory activity against rat adjuvant-induced arthritis, a chronic inflammatory animal model, with comparable analgesic activity. In order to investigate the action mechanisms, tumor necrosis factor and interferone release were studied from human PMMC. It was found that ginkgetin clearly inhibited release of these cytoknes from human PMMC. Ginkgetin was also found to inhibit immunoglobulin M production at 1 - 10 uM. These results may contribute to antiarthritic activity of ginkgetin in vivo.

• 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.

• Natural Product Sciences
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• v.6 no.1
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• pp.1-4
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• 2000

Four biflavonoids were isolated from the leaves of Cephalotaxus koreana. Based on spectroscopic data, the compounds were identified as amentoflavone-7',7",4',4"'-tetramethyl ether, sciadopitysin, ginkgetin and bilobetin, respectively.

• Korean Journal of Pharmacognosy
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• v.21 no.2
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• pp.111-120
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• 1990

Five biflavones and sevenflavonolglycosideswereisolatedfromtheleaves of Ginkgo biloba. They were sciadopitysin(1), ginkgetin(2), isoginkgetin(3), bilobetin(4), amentoflavone(5), kaempferol 3-O-[$6'-O-{\rho}-coumaroyl-{\beta}-_D-glucopyranosyl(1{\rightarrow}2)-{\alpha}-_Lrhamnopyranoside$](6), quercetin 3-O-[$6'-O-{\rho}-coumaroyl-{\beta}-_D-glucopyranosyl(1{\rightarrow}2)-{\alpha}-_Lrhamnopyranoside$](8), rutinosides of kaempferol(7), isorhamnetin(9), quercetin(10), laricitrin(11), and kaempferol 3-O-($2',6'-{\alpha}-_L-dirhamnopyranosyl-{\beta}-_{D}-glucopyranoside$)(12). The structures were established by spectroscopic and chemical methods.

• Proceedings of the PSK Conference
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• 2001.10a
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• pp.209.1-209.1
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• 2001

• Natural Product Sciences
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• v.6 no.4
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• pp.170-178
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• 2000

Flavonoids are natural polyphenolic compounds widely distributed in plant kingdom. Although many flavonoids were found to show anti-inflammatory activity in vitro and in vivo, the potency of anti-inflammatory activity was not enough for a clinical trial. Thus, a search for finding potential flavonoid molecules is continuing. In this review, in vivo anti-inflammatory activity of various flavonoid derivatives is summarized mainly based on the results obtained in authors' laboratories. Among them, several biflavonoids such as amentoflavone and ginkgetin were found to possess anti-inflammatory activity on animal models of acute/chronic inflammation comparable to nonsteroidal and steroidal anti-inflammatory drugs currently used. In respect of their action mechanisms, the effects on arachidonic acid metabolism and nitric oxide production were described. Some flavonoids directly inhibit cyclooxygenase and/or lipoxygenase. Biflavones such as ochnaflavone and ginkgetin are inhibitors of phospholipase $A_2$. In recent studies, certain flavonoids were also found to suppress cyclooxygenase-2 and inducible nitric oxide synthase expression induced by inflammatory stimuli. Therefore, it is suggested that anti-inflammatory activity of the certain flavonoids (mainly flavones, flavonols and biflavonoids) may be mediated by direct inhibition of arachidonic acid metabolizing enzymes as well as suppression of the enzyme expression involved in inflammatory responses.

• 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.20 no.6
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• pp.533-538
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• 1997

Biflavonoid is one of unique classes of naturally-occurring bioflavonoid. Previously, certain biflavonoids were found to possess the inhibitory effects on phospholipase $A_2$ activity and lymphocytes $ proliferation^1$ suggesting their anti-inflammatory/immunoregulatory potential. In this study, effects of several biflavonoids on arachidonic acid release from rat peritoneal macrophages were investigated, because arachidonic acid released from the activated macrophages is one of the indices of inflammatory conditions. When resident peritoneal macrophages labeled with $[^{3}H]$arachidonic acid were activated by phorbol 12-myristate 13-acetate(PMA) or calcium ionophore, A23187, radioactivity released in the medium was increased approximately 4.1-7.3 fold after 120 min incubation compared to the spontaneous release in the control incubation. In this condition, biflavonoids (10 uM) such as ochnaflavone, ginkgetin and isoginkgetin, showed inhibition of arachidonate release from macrophages activated by PMA (32.5-40.0% inhibition) or A23187 (21.7-41.7% inhibition). Amentoflavone showed protection only against PMA-induced arachidonate release, while apigenin, a monomer of these biflavonoids, did not show the significant inhibition up to 10 uM. Staurosporin (1 uM), a protein kinase C inhibitor, showed an inhibitory effect only against PMA-induced arachidonate release (96.8% inhibition). Inhibition of arachidonate release from the activated macrophages may contribute to an anti-inflammatory potential of biflavonoids in vivo.

• Korean Journal of Pharmacognosy
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• v.24 no.1
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• pp.54-57
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• 1993

The seasonal variations of five biflavones from Ginkgo biloba leaves from May to November were investigated by a reversed phase HPLC method. The total amount of biflavones was increased with time to reach its maximum in yellow autumnal leaves. Each biflavone showed a similar tendency. It increased rapidly about 3.1-fold from May to June and thereafter gradually increased about 2.5-fold. The ratio of each biflavone content to the total amount of biflavones was in the order of as follows: isoginkgetin>sciadopitysin>bilobetin>ginkgetin>amentoflavone.

• Natural Product Sciences
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• v.2 no.1
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• pp.1-8
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• 1996

Flavonoids are widely distributed polyphenol compounds in plant kingdom and known to possess varieties of biological/pharmacological activities in vitro and in vivo. A search for antiinflammatory/immunoregulatory flavonoids as potential therapeutic agents has been continued, since serious side effects of currently used nonsteroidal and steroidal antiinflammatory drugs limit their long term uses for the inflammatory disorders. In this reserch, various flavonids were isolated and tested for their in vivo antiinflammatory activity and in vitro inhibitory activity of lymphocyte proliferation. Using a mouse ear edema assay, it was found that certain flavones/flavonols possess mild antiinflammatory activity and a C-2,3-double bond might be essential. Isoflavones were less active. These flavonoids inhibited in vitro lymphocyte proliferation, relatively specific for T-cell proliferation $(IC_{50}=1-10\;{\mu}M)$ and the inhibition was reversible. We have also tested several biflavonoid derivatives, since we recently found that biflavones were phospholipase $A_2$ inhibitors. It was demonstrated that biflavones such as ochnaflavone and ginkgetin inhibited lymphocyte proliferation induced by both concanavaline A and lipopolysaccharide. The inhibition was irreversible in contrast to that of flavones/flavonols. And antiinflammatory activity of biflavonoids are discussed.