• Korean Journal of Pharmacognosy
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• v.21 no.2
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• pp.148-152
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• 1990

Seven flavonol glycosides from the EtOAc fraction of Ginkgo biloba leaves were identified by high performance liquid chromatography. Separation by reversed phase chromatography on $Lichrosorb^{\circledR}$ RP-18 column was achieved by isocratic elution. The content of the major acylated flavonol glycoside, kaempferol 3-0-[$6'-O-{p}-coumaroyl-{\beta}-_D-glucosyl(1{\rightarrow}2)-{\alpha}-_L-rhamnoside$] was about 8.0% and 0.55% for EtOAc fraction and MeOH extract, 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.

• Journal of Applied Biological Chemistry
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• v.48 no.2
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• pp.101-104
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• 2005

DXS catalyzes the first step of MEP pathway. Escherichia coli disruptants defective in dxs were constructed by insertional mutation and characterized. Selected disruptant, DXM3, was auxotrophic for DX or ME. Putative class 1 DXS ORF from Ginkgo biloba was shown to rescue DXM3 grown without DX or ME supplementation. The putative ORF was thus confirmed as DXS1. The disruptant was demonstrated to be useful for DSX screening.

• Korean Journal of Pharmacognosy
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• v.31 no.2
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• pp.240-244
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• 2000

Antimutagenicity profiles of the enzymatic browning reaction products(EBRP) were investigated. The rec-assay with Bacillus subtilis strains $H17(rec^+)$ and $M45(rec^-)$ was carried out using their spores. The biological activities were evaluated for seven different enzymatic browning reaction products, which resulted from the reactions of seven polyphenols with polyphenol oxidase isolated from Ginkgo biloba leaves. In the spore $rec^-$ assay, most of the polyphenolic compounds tested were positive, whereas their enzymatic browning reaction products were tested negative. The mutagenicity of enzymic browning mixtures of the polyphenols and the enzymes obtained from Ginkgo biloba leaves showed negative results in the mutagenicity test using Bacillus subtilis strains $H17(rec^+)$ and $M45(rec^-)$. In the case where polyphenol oxidase inhibitors were added in the enzymatic reaction mixtures with polyphenols, the polyphenols showed mutagenic effect in the spore $rec^-$ assay. This suggests that the activity of polyphenol oxidase is decreased.

• Journal of Plant Biology
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• v.38 no.3
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• pp.281-288
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• 1995

The progressive differentiation of interfascicular cambium from residual meristem in the first internode of Ginkgo biloba seedlings was elucidated by light and electron microscopy. The cells of residual meristem were small and homogeneous and heterogeneous in their arrangement but those of the adjacent cortex and pith were large and homogeneous. Some interprocambial residual meristem progressively became elongated and vacuolated during the process of the differentiation. In tangential section, residual meristem composed of long and short cells. The eventual interfascicular cambium had long fusiform initials and short ray initials. Storage materials in the cells progressively disappeared from the interprocambial residual meristem and were absent in early interfascicular cambium. Both the radial and tangential walls of cells of the interprocambial residual meristem were almost the same, but the radial wall became progressively thicker than the tangential wall during differentiation of interfascicular cambium. From these results, it is clear that interfascicular cambium is gradually differentiated from residual meristem.

• Korean Journal of Pharmacognosy
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• v.20 no.1
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• pp.43-47
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• 1989

An attempt was made to increase the yield of extraction of ginkgoflavonglycosides from leaves of Ginkgo biloba by treatments of with Cellulase C and macerating enzymes. The yield of dried extract and its contents of ginkgoflavonols, when treated only with cellulase C, were analyzed to be 1. 99% and 0. 38%, respectively. The contents of ginkgoflavonglycosides in the dried extracts were calculated to be 25. 28%. By the treatment with a mixture of three enzymes, cellulase C: cellulase NC and macerosin (1 : 1 : 2), the yield of the dried extract, ginkgoflavonols as well as their glycosides were determined to be 2. 48%, 0. 48% and 24. 16%, respectively.

• Korean Journal of Pharmacognosy
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• v.24 no.1
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• pp.47-53
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• 1993

The seasonal variations of the major six flavonol glycosides(kaempferol 2,6-dirhamnosyl glucoside, quercetin 3-O-rutinoside, kaempferol 3-O-rutinoside, isorhamnetin 3-O-rutinoside, quercetin 3-O-coumaroyl glucorhamnoside and kaempferol 3-O-coumaroyl glucorhamnoside) in Ginkgo biloba leaves were investigated. The contents were determined by HPLC on reversed phase $C_{18}$ column. This result showed that the percentage of six flavonol glycosides decreased during the season from 1.57% in May to 0.39% in November. The content of each flavonol glycoside indicated a similar tendency to decrease. However, the contents of rutinosides of kaempferol, quercetin and isorhamnetin fluctuated markedly than those of coumaroyl glucorhamnosides of kaempferol and quercetin and kaempferol 2,6-dirhamnosyl glucoside.

• 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.

• Journal of Applied Biological Chemistry
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• v.42 no.2
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• pp.97-99
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• 1999

Endophytic fungi from Ginkgo biloba and Taxus cuspidata in Korea were screened for production of taxol. Eighteen and twelve fungal isolates from G. biloba and T. cuspidata, respectively, were shown to produce immunologically detectable amount of taxol. The highest production of taxol at 260 ng/l was achieved by stationary culture of an Alternaria isolate from G. biloba. The strain also produced unidentified antifungal agent(s) against Pythium ultimum. However, the activity gradually decreased when the strain was stored at $4^{\circ}C$ for 6 months.

• Korean Journal of Veterinary Service
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• v.35 no.3
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• pp.191-195
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• 2012

Accumulated evidence indicate that Ginkgo biloba extract (EGb 761) acts as an antioxidant and scavenger of free radicals as well as influencing apoptotis. Earlier studies have employed the inflammatory agent lipopolysaccharide (LPS) to induce severe sepsis. In the present study, we examined whether the intraperitoneal injection of EGb 761 increases the survival rate of mice in the LPS-induced severe sepsis model. The survival rate was significantly increased by 30% in mice administered with 100 mg/kg of EGb 761 but not in mice administered with 50 mg/kg EGb 761. In addition, pre-treatment with EGb 761 increased the survival rate (30%) but post-treatment with EGb 761 did not. These results suggest that EGb 761 may have clinical potential in preventing sepsis induced mortality.