Production of ginkgolides and bilobalide by Ginkgo biloba plants and tissue cultures

The accumulation of the terpenes ginkgolides and bilobalide in Ginkgo biloba was reported in plants as well as in plant cell cultures. Several hundred plants cultivated under controlled conditions in the field have been analyzed for their terpene production over many years. Cross-pollination experiments were performed with mature trees and the terpene content of the progeny was analyzed. The age of the tree is the main factor influencing the terpene content of the leaves as the level always decreases dramatically between young and old trees. 80 cell culture strains have been established and ginkgolides analyzed by GC/MS. These cell cultures reveal very low amounts of terpenes (1 microgram g-1 D.W. or less). On the contrary, isolated in vitro root cultures accumulate terpenes at the same concentration as the young plant leaves (4 mg g-1 D.W.). Attempts to obtain rapid growing roots or even hairy-roots did not succeed but the possibility to transform Ginkgo cell strains has been demonstrated.     

In vitro studies on penetration of terpenes from matrix-type transdermal systems through human skin

Polyurethane matrices containing up to 39% of the terpenes eucalyptol, L-limonene, D-limonene, dipentene or terpinolene were produced. Release of the terpenes directly to the acceptor fluid, as well as through isolated human epidermis and dermis, was studied. In the presence of dermis the penetration profiles were very similar to the release profiles, indicating that dermis does not present a barrier for penetration of terpenes. For all terpenes the penetration was slower in the presence of epidermis (K(p) was in the range 0.21-1.8x10(-3) cm/h). Release and penetration through the epidermis and dermis were fastest for dipenetene (mixture of D-limonene and L-limonene), being at least 3-4 times faster than for D-limonene and L-limonene. Large amounts of terpenes found in epidermis (approximately 1.5 mg/cm(2)) indicate that affinity of these compounds to the stratum corneum is very high.     

Terpenes and the Lipid–Protein–Partitioning Theory of Skin Penetration Enhancement

A series of terpenes has been assessed as skin penetration enhancers towards the model polar penetrant 5-fluorouracil (5-FU). Cyclic terpenes were selected from the chemical classes of hydrocarbons (e.g., -pinene), alcohols (e.g., -terpineol), ketones (e.g., carvone), and oxides (e.g., 1,8-cineole, ascaridole). Permeation experiments were performed on excised human epidermal membranes and the terpenes varied in their activities; -pinene only doubled the permeability coefficient of aqueous 5-FU, whereas 1,8-cineole caused a near 95-fold increase. Essential oils, e.g., chenopodium (70% ascaridole), were less effective than the corresponding isolated terpenes. 5-FU is less soluble in the terpenes than in water, and the terpenes did not exert their action by increasing partitioning of the drug into the membranes as illustrated by stratum corneum:water partitioning studies. The penetration enhancers increased drug diffusivity through the membranes, an effect which correlated empirically with the enhancer activities. The principal mode of action of these accelerants may be described by the lipid–protein–partitioning theory; the terpenes interacted with intercellular stratum corneum lipids to increase diffusivity, and the accelerant effects were not due to partitioning phenomena. Keratin interaction was assumed negligible.     

Prevention of butylated hydroxytoluene-induced lung damage in mice by cedar terpene administration.

Mice responded to an ip injection of 400 mg/kg butylated hydroxytoluene (BHT) with a loss of body weight and a rise in lung weight characterized by increases in cellularity, rate of thymidine incorporation into DNA, and total lung DNA content. These responses did not occur, however, if (a) other antioxidants, substituted phenols or BHT metabolites were used rather than BHT itself; (b) mice were under 3 weeks of age; and (c) the mice were exposed to cedar terpenes, either in the form of cedarwood shavings used as cage bedding or by a single ip injection of sesquiterpenoid compounds derived from cedarwood. This prevention of BHT-induced lung damage by the cedar terpenes could not be overcome either by increasing the BHT dose up to 2500 mg/kg, or by delaying terpene administration until 2 hr after the mice had been injected with BHT. The resistance conferred by the terpenes was fully reversible within 4 days after removal of the terpenes from the mice. The lung weights in each of 13 different inbred strains of mice were increased by BHT, and this increase could be prevented by cedar terpene administration. The mechanism(s) by which the terpenes prevent BHT toxicity is/are unknown. The terpenes may act at the level of BHT metabolism, either by preventing activation of BHT to an active metabolite, or by accelerating BHT degradation, or both. This is suggested by the observation that immature mice which cannot metabolize drugs to the same extent as adults are naturally resistant to BHT and also by earlier studies which showed induction of drug metabolizing enzymes by cedar terpenes.     

The effect of phenobarbital pretreatment on the metabolism, covalent binding, and cytotoxicity of aflatoxin B1 in primary cultures of rat hepatocytes

The effect of phenobarbital (PB) pretreatment on the metabolism, covalent binding, and cytotoxicity of [14C]aflatoxin B1 (AFB1) was studied in primary hepatocyte cultures. Hepatocytes from control and PB-pretreated rats were isolated from perfused liver biopsies and cultured in a chemically defined, hormone-supplemented medium. [14C]AFB1, dissolved in medium, was added to cultures at 20-22 h. The metabolism of AFB1 to water-soluble products and its binding to trichloroacetic acid-precipitable macromolecules were assessed 0.5 to 24 h later. At 6 h, PB pretreatment reduced total binding to macromolecules by 31% and reduced binding to RNA and DNA by 61% and 66%, respectively. In addition, PB protected cultures from the cytotoxic effects of AFB1, as evidenced by a significantly reduced (p less than 0.05) leakage of lactate dehydrogenase into the medium at 51 h. Elevated mixed-function oxidase and glutathione S-transferase activities, as well as higher levels of AFB1-glutathione conjugate were measured in cultures from rats pretreated with PB. The protective action of PB was concluded to be due to the induction of hepatic glutathione S-transferases responsible for the detoxification of AFB1.     

Effect of passive and iontophoretic skin pretreatments with terpenes on the in vitro skin transport of piroxicam

The enhancing effect of several terpenes (thymol, menthone and 1,8-cineole) in the percutaneous permeation of piroxicam (Px), either passive or iontophoretically, was investigated. These terpenes were applied, on the skin membrane, as a passive and iontophoretic skin pretreatment. Px was delivered from carbopol gels containing hydroxypropyl-beta-cyclodextrin (2% w/w Px). An increase in Px flux values, both passive and iontophoretic after skin pretreatment with 5% terpenes/50% EtOH, was found to be in the following order: thymol>menthone>1,8-cineole. Iontophoretic skin pretreatment with terpenes produced a slight increase in the passive flux of Px, in comparison with the passive skin pretreatment. This result indicated that iontophoresis could modify the skin morphology and consequently, increase the passive transport of Px. However, when Px was transported iontophoretically, passive skin pretreatment with terpenes, produced higher flux values than iontophoretic skin pretreatment. These results could be explained by the fact that with the iontophoretic pretreatment, terpenes could penetrate into the skin and limitate the movement of the ionized species, across the skin, during the iontophoretic experiments. The amount of Px retained in the skin after all experiments was related to flux values across skin.     

Activity on the CNS of crude extracts and of some diterpenoids isolated from Euphorbia calyptrata suspended cultures.

Crude methanolic extracts from both root and cell cultures of Euphorbia calyptrata were investigated and found to be active on the CNS. An active fraction was isolated from the methanolic extract of suspension cultures; this possesses significant depressant activity on the CNS. When compared with the crude methanolic root extract, this fraction showed the presence of some common products, four of which were isolated and characterized as helioscopinolides A, C, D, and E. The pure products, administered intraperitoneally to mice, showed different activities on the CNS. Helioscopinolide C showed a clear depressant activity, helioscopinolide E a mild, short depressant effect, while helioscopinolides A and D had an opposite excitatory effect.     

Mono- and Diterpenes from Cell Cultures of Thuja occidentalis

Cell cultures of THUJA OCCIDENTIALIS L. were found to biosynthesize various mono- and diterpenes when grown on B5-medium. The identification of the constituents was achieved mainly by capillary GLC-MS using fused silica columns and E.I.-mass spectrometry. Monoterpenes of the menthane type were only isolated from the culture medium whereas diterpenes were found in the cell extracts. Thujaplicin derivatives, monoterpenes of an irregular type, were detected in the medium as well as in the cells. Major differences were found between the terpene composition of the cell culture extracts and those from THUJA leaves. The cell cultures accumulated some compounds which are presently unknown as constituents of THUJA plants. On the other hand, the cultures were evidently unable to synthesize the thujone type of monoterpenes.     

人骨髓间充质干细胞对再生障碍性贫血患者T细胞活化的影响

目的探讨人骨髓间充质千细胞在体外对再生障碍性贫血患者T细胞活化的影响。方法从人骨髓分离培养间充质干细胞，用尼龙棉柱分离T淋巴细胞，分别以不同数量间充质干细胞加入到植物血凝素刺激的再生障碍性贫血患者T淋巴细胞活化体系中，通过流式细胞仪获取数据，计算CD3^＋CD25^＋和CD3^＋CD38^＋T细胞的表达率。结果当间充质干细胞为1×10^4／孔时，与单独培养的再生障碍性贫血患者T淋巴细胞（对照组）相比，间充质干细胞对再生障碍性贫血患者T淋巴细胞CD25及CD38的表达呈明显抑制作用，差异有统计学意义（P〈0．01）。当间充质干细胞为1×10^3／孔时，与对照组相比无统计学意义。结论间充质干细胞在体外抑制再生障碍性贫血患者T细胞的活化，且这种抑制作用具有数量依赖性。     

Inhibition of serum deprivation- and staurosporine-induced neuronal apoptosis by Ginkgo biloba extract and some of its constituents

Previous studies have already demonstrated that some constituents of an extract of Ginkgo biloba (EGb), such as ginkgolide B and bilobalide, protect cultured neurons from hypoxia- and glutamate-induced damage. This prompted us to investigate whether they were also able to inhibit neuronal apoptosis. We induced apoptosis in cultured chick embryonic neurons as well as in mixed cultures of neurons and astrocytes from neonatal rat hippocampus by serum deprivation and staurosporine. The increase in the percentage of apoptotic chick neurons from 12% in controls to 30% after 24 h of serum deprivation was reduced to control level by EGb (10 mg/l), ginkgolide B (10 microM), ginkgolide J (100 microM) and bilobalide (1 microM). After treatment with staurosporine (200 nM) for 24 h we observed 74% apoptotic chick neurons. This percentage of apoptotic neurons was reduced to 24%, 62% and 31% in the presence of EGb (100 mg/l), ginkgolide J (100 microM) and ginkgolide B (10 microM), respectively. Bilobalide (10 microM) decreased apoptotic damage induced by staurosporine treatment for 12 h nearly to the control level. In mixed neuronal/glial cultures, the extract of EGb (100 mg/l) and bilobalide (100 microM) rescued rat neurons from apoptosis caused by serum deprivation, whereas, bilobalide (100 microM) and ginkgolide B (100 microM) reduced staurosporine-induced apoptotic damage. Ginkgolide A revealed no anti-apoptotic effect in either serum-deprived or staurosporine-treated neurons. Our results suggest that EGb and some of its constituents possess anti-apoptotic capacity and that bilobalide is the most potent constituent.     

Effect of oxygen concentration on the expression of glutathione S-transferase activity in periportal and perivenous rat hepatocyte cultures.

Cultures of perivenous (PV) and periportal (PP) hepatocytes could provide suitable in vitro models for studying the zone-specific hepatotoxic potential of xenobiotics. However, it is not known whether cultured PP and PV hepatocytes keep their phenotypes when the microcirculation of the liver changes. This question has been studied by culturing rat hepatocytes at 13 and 4% (v/v) O(2), respectively, mimicking the acinar oxygen gradient. PP and PV adult rat hepatocytes were isolated by digitonin-collagenase in situ perfusion and cultured on plastic Falcon and gas-permeable Petriperm dishes in Williams' E medium and kept at 13 and 4% (v/v) O(2), respectively. Cultures at 20% (v/v) O(2) on plastic dishes served as a control. Two types of cultures were studied, namely conventional cultures either unsupplemented or supplemented with 30 mM pyruvate. The activities of glutamine synthetase (GS) and glutathione S-transferase (GST) were measured in freshly isolated PP and PV hepatocytes and all cultures. The heterogeneous expression of GS (PV>PP), observed in freshly isolated hepatocytes, was kept for at least 4 days in culture. Total, Mu and Alpha class GST activities were predominantly expressed in PV freshly isolated cells. However, no beneficial effect could be observed in culture by exposing the cells to their specific in vivo oxygen concentration. The best maintenance of GST PV predominance in culture was observed in Petriperm dishes at 20% (v/v) O(2), as well in pyruvate-supplemented as unsupplemented cultures. PV GST predominance was thus kept in particular when the highest oxygen concentration was used and made available to the cells through the gas-permeable membranes. The results on GS PV predominance support these findings.     

Application of topological indexes for evaluation of the TLC separation of selected essential oil components

The selected essential oil components (menthol, (+)bomeol, geraniol, linalool, carvone, camphor, (IR)-(-)fenchone) were separated by adsorption thin-layer chromatography using benzene as mobile phase. Investigated terpenes were characterized by selected topological indexes based on the adjacency and distance matrix. From among all the topological indexes counted only Si(o) index (the sum of the distance between the oxygen atom and all the remaining atoms in graph) as well as cluster Randi? indexes (4chi(c), and 4chi(v)c) allow for estimation of the chromatograms obtained. With the fact mentioned above, there exists the possibility of prediction of relative situation on a chromatogram of the terpenes investigated. For the rest of topological indexes that possibility was not stated.     

Induced daldinin A, B, C with a new skeleton from cultures of the ascomycete Daldinia concentrica

Daldinin A, B, C with a new skeleton, together with four known compounds, were induced and isolated from cultures of the ascomycete Daldinia concentrica. Their structures were elucidated by spectroscopic analysis, and that of daldinin A was confirmed by single-crystal X-ray diffraction.     

Oxide terpenes as human skin penetration enhancers of haloperidol from ethanol and propylene glycol and their modes of action on stratum corneum

In this study, two terpenes with the same functional group; limonene oxide and pinene oxide were used at 5% w/v concentration in 50% v/v ethanol and 100% v/v propylene glycol (PG) to enhance the in vitro permeation of haloperidol (HP) through the human epidermis (or stratum corneum, SC). The enhancement mechanism of terpenes from both solvents was elucidated with HP-SC binding studies, Fourier transform infrared spectroscopy and differential scanning calorimetry. The enhancement activity of these terpenes was higher in 50% v/v ethanol than in 100% v/v PG. These terpenes in 50% v/v ethanol were predicted to provide the required therapeutic plasma concentration and daily-permeated amounts of the drug. Limonene oxide showed higher enhancement in both solvents, which was attributed to its less bulky structure. The terpenes in both solvents did not increase the partition of HP. Instrumental studies showed that these terpenes in 50% v/v ethanol extracted the SC lipids, disrupted the bilayer packing and partially fluidised the lipids. Limonene oxide in 100% v/v PG possibly disrupted the lipid bilayer, whilst leaving the overall bilayer structure intact and pinene oxide in the same vehicle fluidised the lipids within the ordered environment. This study showed that the mode of interactions of terpenes with SC were different in two solvent systems.     

Proliferative responses of quail aortic smooth muscle cells to benzo[a]pyrene: implications in PAH-induced atherogenesis.

Repeated exposure of avian and rodent species to benzo(a)pyrene (BaP) has been associated with the development of aortic lesions of atherosclerotic etiology. Because the occurrence of these lesions may involve alterations in the regulation of smooth muscle cell (SMC) growth, the present studies were conducted to evaluate the proliferative responses of quail aortic SMCs to BaP treatment in vivo and in vitro. Measurements of [3H]thymidine incorporation and cell growth were conducted in cultured aortic SMCs isolated from male Japanese quail treated with 10 mg/kg BaP or vehicle weekly for 10 weeks or in naive aortic SMCs exposed in vitro to BaP (0.003-30 microM). Inhibition of DNA synthesis was observed in primary and early passage cultures of aortic SMCs isolated from BaP-treated quail relative to controls. Continued propagation of these cultures yielded a population of BaP cells which proliferated at faster rates than controls. The proliferative phenotype induced by BaP was first observed after the tenth passage and preserved in all subsequent passages tested. In vitro growth of SMCs from BaP-treated animals was serum- and anchorage-dependent. A 24-h exposure of cycling SMC cultures to BaP (0.003-30 microM) was associated with a dose-dependent decrease in DNA synthesis and significant delay in the progression of SMCs through the cell cycle. A time-course study revealed that maximal inhibition of DNA synthesis occurred 10 h after addition of 3 microM BaP to cycling cultures of SMCs. As seen in SMCs isolated from BaP-treated quail, serial subculture of SMCs exposed to 0.3 microM BaP in vitro for 24 h yielded a fast-growing population of cells. In these cultures, expression of the proliferative phenotype was observed after the fifth passage. These data suggest that BaP induces the expression of a proliferative phenotype in aortic SMCs characterized by enhanced serum responsiveness. This phenotypic modulation may contribute to the initiation and/or progression of vascular lesions of atherosclerotic etiology induced by BaP.     

Permissive and suppressive effects of dexamethasone on enzyme induction in hepatocyte co-cultures

1. Steroids are known to act as permissive factors in hepatocytes. This study shows that dexamethasone (DEX) is a permissive factor for induction of CYP2B1/2, CYP3A1, CYP2A1 and probably also CYP2C11 in cultures with primary rat hepatocytes. 2. The induction factor of phenobarbital (PB)-induced formation of 16beta-hydroxytestosterone (OHT), a testosterone biotransformation product predominantly formed by CYP2B1, is increased 18-fold by the addition of 32 nM DEX to the culture medium. Interestingly, higher concentrations of DEX up to 1000 nM led to a concentration-dependent maximally 5-fold decrease (p = 0.002) of phenobarbital-induced 16beta-OHT formation compared with the effect observed with 32 nM DEX. Thus, DEX shows permissive and suppressive effects on enzyme induction depending on the concentration of the glucocorticoid. 3. Qualitatively similar but smaller permissive and suppressive effects of DEX were observed for PB-induced CYP3A1 activity as evidenced by formation of 2beta-, 6beta- and 15beta-OHT. 4. DEX is a permissive factor for induction of CYP2A1 activity by 3-methylcholanthrene (3MC), as evidenced by the formation of 7alpha-OHT. Without addition of DEX, 3MC did not induce formation of 7alpha-OHT, whereas an almost 3-fold induction occurred in the presence of DEX. In contrast to CYP2B and CYP3A, concentrations up to 1000 nM DEX were not suppressive for the induction of CYP2A1. 5. We described recently a technique that allows preparation of cultures from cryopreserved hepatocytes. An almost identical influence of dexamethasone on enzyme induction was observed here in cultures from cryopreserved compared with freshly isolated hepatocytes. 6. Cultures with primary hepatocyte cultures represent a well-established technique for the study of drug-drug interactions. However, a large interlaboratory variation is known. Our study provides evidence that differences in glucocorticoid concentration in the culture medium contribute to this variation.     

Production of triterpenoids in liquid-cultivated hairy roots of Galphimia glauca

The production of three triterpenoids from Galphimia glauca hairy root cultures, the sedative principle galphimine E (2), the recently described glaucacetalin A (3), and maslinic acid (6), was quantified by HPLC in the biomass and the culture medium. Batch cultures of the hairy root line VYT, obtained through infecting cotyledons with Agrobacterium rhizogenes ATCC 15 834, were grown for 41 days in shake flasks containing B5 medium without phytohormones. A maximum biomass of 11 g/L DW was obtained on day 33, while the doubling time was 6 days. Throughout the growth cycle fresh and dry weights as well as triterpene production were registered. Glaucacetalin A (3), excreted into the culture media, reached a maximum amount of 2.14 mg/L after 21 days while galphimine E (2) and maslinic acid (6) were recovered from the root biomasses reaching maximum concentrations of 0.11 and 0.43 mg/g, respectively, on day 39.     

节孢状镰孢菌含氮代谢产物的研究Ⅰ.恩镰孢菌素B的分离提纯及药理活性试验

已知镰孢菌属的几个种产生一种含氮化合物——恩镰孢菌素B,但尚未见有从节孢状镰孢菌中分离到这种化合物的报道。为了开发青藏高原的微生物资源,对本地区分离到一株节孢状镰孢菌的含氮代谢产物进行了研究。     

Development of a Monoclonal Antibody-Based icELISA for the Detection of Ustiloxin B in Rice False Smut Balls and Rice Grains

Rice false smut is an emerging and economically-important rice disease caused by infection by the fungal pathogen Villosiclava virens. Ustiloxin B is an antimitotic cyclopeptide mycotoxin isolated from the rice false smut balls that formed in the pathogen-infected rice spikelets. A monoclonal antibody (mAb) designated as mAb 1B5A10 was generated with ustiloxin B—ovalbumin conjugate. A highly-sensitive and specific indirect competitive enzyme-linked immunosorbent assay (icELISA) was then developed. The median inhibitory concentration (IC₅₀) of the icELISA was 18.0 ng/mL for the detection of ustiloxin B; the limit of detection was 0.6 ng/mL, and the calibration range was from 2.5 to 107.4 ng/mL. The LOD/LOQ values of the developed ELISA used for the determination of ustiloxin B in rice false smut balls and rice grains were 12/50 μg/g and 30/125 ng/g, respectively. The mAb 1B5A10 cross-reacted with ustiloxin A at 13.9% relative to ustiloxin B. Average recoveries of ustiloxin B ranged from 91.3% to 105.1% for rice false smut balls at spiking levels of 0.2 to 3.2 mg/g and from 92.6% to 103.5% for rice grains at spiking levels of 100 to 5000 ng/g. Comparison of ustiloxin B content in rice false smut balls and rice grains detected by both icELISA and high performance liquid chromatography (HPLC) demonstrated that the developed icELISA can be employed as an effective and accurate method for the detection of ustiloxin B in rice false smut balls, as well as rice food and feed samples.