Ginkgo biloba extract alleviates fatty liver hemorrhagic syndrome in laying hens via reshaping gut microbiota

Background Ginkgo biloba extract(GBE)is evidenced to be effective in the prevention and alleviation of metabolic disorders,including obesity,diabetes and fatty liver disease.However,the role of GBE in alleviating fatty liver hemorrhagic syndrome(FLHS)in laying hens and the underlying mechanisms remain to be elucidated.Here,we investigated the effects of GBE on relieving FLHS with an emphasis on the modulatory role of GBE in chicken gut microbiota.Results The results showed that GBE treatment ameliorated biochemical blood indicators in high-fat diet(HFD)-induced FLHS laying hen model by decreasing the levels of TG,TC,ALT and ALP.The lipid accumulation and pathological score of liver were also relieved after GBE treatment.Moreover,GBE treatment enhanced the antioxidant activity of liver and serum by increasing GSH,SOD,T-AOC,GSH-PX and reducing MDA,and downregulated the expression of genes related to lipid synthesis(FAS,LXRα,GPAT1,PPARγand Ch REBP1)and inflammatory cytokines(TNF-α,IL-6,TLR4 and NF-κB)in the liver.Microbial profiling analysis revealed that GBE treatment reshaped the HFD-perturbed gut microbiota,particularly elevated the abundance of Megasphaera in the cecum.Meanwhile,targeted metabolomic analysis of SCFAs revealed that GBE treatment significantly promoted the production of total SCFAs,acetate and propionate,which were positively correlated with the GBE-enriched gut microbiota.Finally,we confirmed that the GBE-altered gut microbiota was sufficient to alleviate FLHS by fecal microbiota transplantation(FMT).Conclusions We provided evidence that GBE alleviated FLHS in HFD-induced laying hens through reshaping the composition of gut microbiota.Our findings shed light on mechanism underlying the anti-FLHS efficacy of GBE and lay foundations for future use of GBE as additive to prevent and control FLHS in laying hen industry.

The Effect of Ginkgo Biloba Leaf Dropping Pill Combined with Butylphthalide Capsule on Cognitive Dysfunction in Patients after Acute Ischemic Stroke and Its Impact on Serum Cytokines

Objective: To investigate the therapeutic effect of Ginkgo biloba extract dropping pills combined with butylphthalide capsules on cognitive dysfunction in patients after acute ischemic stroke (AIS) and its impact on serum cytokines CRP, IL-6, and Hcy. Methods: This study selected 76 patients with cognitive dysfunction after ischemic stroke who were hospitalized at Zhuji People’s Hospital from January 2023 to January 2024. The patients were divided into two groups. The control group was treated with butylphthalide capsules, while the combination group received Ginkgo biloba extract dropping pills in addition to the treatment given to the control group. The neurological function, cognitive function, activities of daily living, and levels of serum cytokines CRP, IL-6, and Hcy were compared between the two groups after 1 month and 3 months of treatment. Results: The NIHSS scores, MMSE scores, ADL scores, and levels of CRP, IL-6, and Hcy in both groups showed statistically significant differences compared to before treatment (P Conclusion: The combination of Ginkgo biloba extract dropping pills and butylphthalide capsules has a better therapeutic effect on cognitive dysfunction in patients after ischemic stroke. It can improve the neurological function and cognitive function of patients, enhance their ability to perform daily activities, and reduce inflammatory responses.

Effects of a Cocktail Supplement of Ginkgo Biloba and Acai Extract on Cognitive Symptoms of Parkinson’s Disease

Parkinson’s Disease (PD) is a neurodegenerative disorder characterized by motor and non-motor symptoms, including cognitive impairment. Current treatments often involve synthetic drugs with significant side effects and potential for dependency. This study investigates the effects of a natural supplement combination of Ginkgo Biloba and Acai Extract on cognitive symptoms in a 77-year-old male with PD. The participant underwent a three-month supplementation regimen, with cognitive function assessed using the Montreal Cognitive Assessment (MoCA) test before and after the intervention. The results indicated an improvement in cognitive scores, suggesting that the combination of Ginkgo Biloba and Acai Extract may offer a promising alternative or adjunct to conventional PD treatments. This study highlights the potential of natural supplements in managing PD symptoms and calls for further research with larger sample sizes to confirm these findings. Human data was performed in accordance with the Declaration of Helsinki by the Roxbury District IRB Board (IRB Number: IRB00011767).

Effects of ginkgo flavone aglycone on atherosclerosis based on network pharmacology,molecular docking,and in vitro experiments

Background:Ginkgo flavone aglycones(GA),a Ginkgo(Ginkgo biloba)extract,has been proven to have good biological activity in atherosclerosis(AS)treatment.Moreover,its active compounds and the corresponding mechanism for the treatment of AS remain unclear.Methods:To evaluate and identify the potential pharmacological mechanisms of GA in AS treatment,the program Cytoscape was used to generate network mappings of the GA-AS-potential target gene.GO and KEGG enrichment analyses were performed to further investigate the potential mechanism of AS and the pharmacological properties of GA.A molecular docking approach was utilized to determine the GA components that interact with Akt.In vitro experiments were carried out to identify the anti-atherosclerotic effects of GA by targeting Akt.Results:Network pharmacological research determined that the active components of GA(quercetin,kaempferol,and isorhamnetin)correlated with AS target genes such as AKT1,EGFR,SRC,ESR1,PTGS2,MMP9,KDR,GSK3B,APP,and MMP2,respectively.GO enrichment and KEGG analysis showed that PI3K-Akt signaling may play an important role in GA treatment.Molecular docking experiments indicated that quercetin,kaempferol,and isorhamnetin integrate into the binding pockets of the most potentially beneficial GA-AS target protein(Akt).Consequently,cell experiments were conducted to support the anti-atherosclerotic activity of GA on AS by inhibiting the phosphorylation of AKT1 and its downstream signaling molecules,which regulated the proliferation of HASMCs.Conclusion:Our results detailed GA's active ingredients,potential targets,and molecular basis against AS.GA may exert anti-atherosclerotic effects by suppressing Akt phosphorylation and inhibiting the proliferation of HASMCs.It also proposed a viable approach to determining the scientific foundation and therapeutic mechanism of Chinese herbal medicine extracts in disease therapy.

Efficacy and Safety of Ginkgo Biloba Tincture(银杏叶酊) Combined with Conventional Medication in the Treatment of Cerebral Infarction: Systematic Review and Meta-analysis

Objective:To analyze the efficacy and safety of Ginkgo biloba tincture combined with conventional medication in the treatment of cerebral infarction by systematic evaluation.Methods:Searched the randomized controlled trials of Ginkgo biloba tincture in treating cerebral infarction.English literatures were searched from PubMed,EMbase,Cochrane Library and Web of Science,and Chinese literatures were searched from Chinese Biomedical Literature Database(CBM),China National Knowledge Infrastructure(CNKI),China Science and Technology Journal Database(VIP)and Wanfang Medical Database.At the same time,we searched dissertations,conference papers,and found relevant unpublished research results reports.Literature quality was evaluated using a"bias risk assessment tool"and Meta-analysis using RevMan 5.4 software(from the Cochrane Collaboration).A total of 29 literatures were retrieved,and finally 4 literatures meeting the standards were included.There were 455 samples involved,including 244 cases in the experimental group and 211 cases in the control group.Results:①Effectiveness analysis:The total effective rate of Ginkgo biloba tincture combined with routine treatment was better than that of the control group[RR=1.26,95%CI(1.07,1.47),P=0.005].The hematocrit of Ginkgo biloba tincture combined with conventional treatment was significantly better than that of conventional treatment alone(P<0.05),The neurological deficits of Ginkgo biloba tincture combined with routine therapy was significantly improved(P<0.05).After Ginkgo biloba tincture combined with conventional therapy,the scores of mini-mental state examination(MMSE),activity daily living scale(ADL)and MOSSF-36 quality of life scale were significantly better than those of the control group(P<0.05).②Safety analysis:3 articles reported the safety of medication.There was no obvious change in blood routine,liver and kidney function results and no adverse reactions in the experimental group and the control group.Conclusion:The above results indicated that Ginkgo biloba tincture combined with conventional treatment can improve the total effective rate of patients with cerebral infarction,and it is safe and has no adverse reactions.However,the number of literatures included in this study is small,and the quality of controlled trials is not good.It is still necessary to adopt clinical controlled trials with reasonable design,outcome indicators in line with international social norms and large sample content to further improve the evidence level of clinical research.

Comparative histology,transcriptome,and metabolite profi ling unravel the browning mechanisms of calli derived from ginkgo(Ginkgo biloba L.)

Gingko biloba accumulates high levels of secondary metabolites of pharmaceutical value.Ginkgo calli develop a typical browning that reduces its regenerative capacity and thus its usefulness.To elucidate the browning mechanism,histological,transcriptomic,and metabolic alterations were compared between green and browning calli derived from immature ginkgo embryos.Histological observations revealed that browning calli had a more loosely arranged cell structure and accumulated more tannins than in green calli.Integrated metabolic and transcriptomic analyses showed that phenylpropanoid metabolism was specifi-cally activated in the browning calli,and 428 diff erentially expressed genes and 63 diff erentially abundant metabolites,including 12 fl avonoid compounds,were identifi ed in the browning calli compared to the green calli.Moreover,the expression of fl avonol synthase(FLS)and UDP-glucuronosyl-transferase(UGT)genes involved in the fl avonoid pathway was more than tenfold higher in browning calli than in green calli,thus promoting biosynthesis of fl avonol,which serves as a substrate to form glycosylated fl avonoids.Flavonoid glycosides constituted the major coloring component of the browning calli and may act in response to multiple stress conditions to delay cell death caused by browning.Our results revealed the cellular and biochemical changes in browning callus cells that accompanied changes in expression of browning-related genes,providing a scientifi c basis for improving ginkgo tissue culturability.

孑遗植物银杏(Ginkgo biloba L.)伴性光合生理特征与进化生态

银杏类是一类古老的雌雄异株植物,目前仅存单科单属。由于银杏在系统发育等方面的独特地位,吸引了科学家从不同方面进行了广泛的研究。在适宜的条件下,测定了生长在野外环境下的成年银杏的雌雄个体的光合特性。研究结果表明,银杏的雌雄植株对光具有相同的表现趋势,光饱和点,光补偿点,光下呼吸速率等均没有明显差异。但是雌性银杏的净光合速率明显大于雄性银杏的净光合速率。这种差异可能与雌性个体在繁衍后代时需要投入更多的能量有关。研究也表明,在与其它的裸子植物和被子植物比较时,银杏的光合能力并没有明显的弱势,因此光合能力可能并不是银杏在第三纪分布受限的直接原因.

Identification of a Sex-Associated RAPD Marker in Ginkgo biloba

The random amplified polymorphic DNA (RAPD) technique was used to amplify DNA fragment, aiming at finding markers linked to the sex determination in Ginkgo biloba L. One thousand and two hundred random decamers had been screened. Of the 8 372 RAPD bands, only a 682 bp RAPD marker generated by a primer (S1478) of random decamer sequence, named S1478-682, was found to be associated with the male plants. This marker was present in all male plants and absent in all female plants. Ginkgo trees collected in both Beijing and Shenyang, China were tested using primer S1478. Positive results were obtained, suggesting S1478-682 could be utilized as a reliable RAPD marker to detect the sexuality of Ginkgo.

Photoinhibition and Photoprotection in Ginkgo biloba leaves: Influence of Temperature, CO 2 and O 2

In midday ginkgo ( Ginkgo biloba L.) leaves have to bear photon flux density over 1400 μmol·m -2 ·s -1 in combination with high temperatures around 35 ℃ at natural habitat. They show typical midday depression of stomatal conductance and of CO 2 assimilation rate. The zeaxanthin changes with light intensity during the day. The influence of the combination of strong light and temperature on photoinhibition was also examined in the laboratory. A low CO 2 internal conductance (31 mmol·m -2 ·s -1 ) was found in ginkgo leaves, which had been exposed to excessive light at temperature between 15 ℃ and 35 ℃ with reduced CO 2 (80 μL·L -1 ) or oxygen (2%) for 2 h, causing a low CO 2 concentration at the carboxylation site and a high proportion of photorespiration. The ratio of electron transport to CO 2 fixation was rather high in ginkgo (16 e -/CO 2 at 25 ℃) as compared with other plants. It increased with temperature also in 2% O 2 which could not be explained solely as due to change of photorespiration. The reduction of oxygen in 340 or 80 μL·L -1 CO 2 had no effect on the extent of photoinhibition at all temperatures, which indicated that electron flow caused by photorespiration in excess light was negligible in protective effect in ginkgo leaves. However, a decreased CO 2 concentration increased photoinhibition, especially at high temperature. It is concluded that the dissipation of excessive excitation energy in the PSⅡ antennae through the xanthophyll cycle may be the major protective mechanism to preventing from the deteriorated effects of strong light in ginkgo leaves.

Study and Application of Fingerprints of Ginkgo biloba Leaves Preparations

Aim To establish a method for determination of Ginkgo biloba L, its extractand preparations with HPLC fingerprints, so as to control the quality of the preparations. MethodsHPLC-DAD method was used to determine the constituents in preparations. Diamonsil? C_(18) (200mm X 4.6 mm, 5 μm) was used as analytical column, and acetonitrile/KH_2PO_4 was used as mobilephase with gradient elu-tion. The column temperature was at 24 ℃. The HPLC profile of chemicalconstituents of control sample and preparations were analyzed using similarity software. Results Thefingerprints of different preparations from different companies were slightly different because ofthe different preparing procedures. Mean while, the fingerprints of different batches of the samepreparation from the same company were similar to each other and the technology of each preparationwas stable. Conclusion This method is accurate, reproducible , simple, and can be used as ananalytical method for the routine quality control of Ginkgo biloba preparations.

High Performance Liquid Chromatography-Electrospray Ionization-Mass Spectrometric Analysis of Bilobalide and Ginkgolides in Ginkgo biloba L. Leaves

The ginkgo terpenoids including bilobalide and ginkgolides are the main pharmaceutical components in the leaves or extracts of Ginkgo biloba L. In this paper, the analysis of bilobalide and ginkgolides in leaves of Ginkgo biloba L. by high performance liquid chromatography (HPLC)-electrospray ionization (ESI)-mass spectrometry (MS) was carried out. The separation was performed on Inertsil ODS3 column with methanol-water (36:64) as mobile phase, with 1 mL·min -1 of flow rate at 35℃. Then the mass spectrum analysis was conducted by ZMD micromass electrospray ionization (ESI)-mass spectrometer (MS). The HPLC total ion chromatogram and selected ion chromatogram (with 325, 407, 423, 439 of m/z) of the sample and ESI-/MS mass spectra of the peaks in the chromatograms were obtained. So bilobalide, ginkgolide A, B, C and J in Ginkgo biloba L. leaves were identified. The method is easy and rapid, with a good accuracy.

The Construction of Fusion Expression Vector Carrying GFP and TP of GGPPS from Ginkgo biloba L.

[Objective]The aim was to construct the fusion gene expression vector which consisted of GFP and TP gene of GGPPS from the Ginkgo biloba L.[Method]The transit-peptide（TP） sequence of GGPPS from cDNA of Ginkgo biloba L.was successfully cloned by using DNA recombination technology,which was then linked to the efficient plant expression vector p1304 ＋ to construct the fusion gene expression vector p1304 ＋-TP.Then engineering strain EHA105-p1304 ＋-TP was constructed by transformed p1304 ＋-TP to Agrobacterium rhizogenes EHA105 using freeze-thaw method.[Result]The fusion gene expression vector which consisted of GFP and TP gene of GGPPS from the Ginkgo biloba L.and engineering strain EHA105-p1304 ＋-TP were successfully constructed.[Conclusion]It lays a foundation for further study of subcellular localization of TP transit peptide,which can help to clarify the molecular mechanism of a key step in biosynthesis of ginkgolides precursors,and also provides an important basis for the research on metabolic engineering of ginkgolide.

Effects of Ginkgo biloba extract EGb761 on neural differentiation of stem cells offer new hope for neurological disease treatment

Stem cell transplantation has brought new hope for the treatment of neurological diseases.The key to stem cell therapy lies in inducing the specific differentiation of stem cells into nerve cells.Because the differentiation of stem cells in vitro and in vivo is affected by multiple factors,the final differentiation outcome is strongly associated with the microenvironment in which the stem cells are located.Accordingly,the optimal microenvironment for inducing stem cell differentiation is a hot topic.EGb761 is extracted from the leaves of the Ginkgo biloba tree.It is used worldwide and is becoming one of the focuses of stem cell research.Studies have shown that EGb761 can antagonize oxygen free radicals,stabilize cell membranes,promote neurogenesis and synaptogenesis,increase the level of brain-derived neurotrophic factors,and replicate the environment required during the differentiation of stem cells into nerve cells.This offers the possibility of using EGb761 to induce the differentiation of stem cells,facilitating stem cell transplantation.To provide a comprehensive reference for the future application of EGb761 in stem cell therapy,we reviewed studies investigating the influence of EGb761 on stem cells.These started with the composition and neuropharmacology of EGb761,and eventually led to the finding that EGb761 and some of its important components play important roles in the differentiation of stem cells and the protection of a beneficial microenvironment for stem cell transplantation.

Cloning and Functional Analysis of HDR Gene from Ginkgo biloba L

[Objective] The aims were to obtain cloning of HDR gene from Ginkgo biloba.and study its function.[Method] The coding sequence of HDR gene was cloned from G.biloba by reversed transcription polymerase chain reaction,which was designated as GbHDR （GenBank accession No.：DQ364231）.The cDNA full-length of GbHDR is 1 827 bp containing a 1 425-bp open reading frame （ORF） encoding a 474-amino-acid polypeptide and constructed into the prokaryotic expression vector pTrcGbHDR.The β-carotene biosynthetic pathway in E.coli strain XL1-Blue was reconstructed by transforming with pAC-BETA.This engineered XL1-Blue was transformed with pTrcGbHDR.[Result] A 1 441 bp GbHDR was obtained containing a 1 425-bp ORF encoding a 474-amino-acid residues of protein,the predicted molecular weight was 53.2 kD,and predicted isoelectric point was 5.76.Functional complementation assay indicated that GbHDR could promote theβ-carotene accumulation in engineered XL1-Blue harboring pTrcGbHDR and pAC-BETA,and as a result,the engineered bacteria showed the brightly orange given by β-carotene.This suggested that GbHDR had the typical function of known HDR genes.[Conclusion] A engineered bacteria of E.coli which could highly accumulate β-carotene was obtained,which will provide candidate genes and targets for realizing β-carotene metabolic engineering.

Establishment of the Agrobacterium-mediated Genetic Transformation System of Ginkgo biloba and the Construction of the Expression Vector of Gb-DXR

[Objective] The research aimed to provide reference for increasing the genetic transformation efficiency of Ginkgo biloba mediated by Agrobacterium.[Method] Taking the mature embryos of Ginkgo biloba seeds as explants,after 48 hours＇ pre-cultivation on MS medium in the absence of phytohormone,GUS gene was transmitted into embryos of Ginkgo biloba mediated by three kinds of Agrobacterium.Transient expression of GUS gene activity was observed through histochemical staining,and the influencing factors of the expression of GUS gene were analyzed.And the expression vector of 1-deoxy-D-xylulose-5-phosphate reductoisomerase in the biosynthesis approach of biobalide precursor of Ginkgo biloba was constructed.[Result] A more suitable genetic transformation scheme was obtained as follows：taking embryos of Ginkgo biloba as explants,using EHA105 Agrobacterium with pCAMBIA1304＋ for infection,co-culture for 3 days and GUS staining.The results showed that transient expression rate of GUS after transformation was higher.[Conclusion] The research provide a more effective method for further study on the transgene of Ginkgo biloba.

Preliminary Study on Water Physiological Characters of Male and Female Ginkgo biloba L.

[Objective] The experiment aimed to study the difference of water physiology of male and female Ginkgo biloba L. for discussing the strategy of water utilization as well as the important role of this difference during evolution process. [Method] The stem sap flow, stomatal conductance(Gs), transpiration rate(Tr) and water use efficiency (WUE) of male and female Ginkgo biloba L. were comparatively studied. [Result] The day-night processes of flow on male and female Ginkgo biloba L. were similar. The flow on male and female Ginkgo biloba L. in day were almost same while the flow at night on male Ginkgo biloba L. was bigger than that on female Ginkgo biloba L. The Tr and Gs of male and female Ginkgo biloba L. were high in morning and at night but low at noon ,while Tr and Gs of female Ginkgo biloba L. in morning and at night were higher than these of male Ginkgo biloba L. at the same time point. However, these indexes of female plant were lower than these of male plant from 11:00 to 14:00. WUE changing trends of male and female Ginkgo biloba L. were similar, while average water utilization rate of female Ginkgo biloba L. was slightly lower than that of male Ginkgo biloba L. [Conclusion] Compared with other companion plants, water physiology of male and female Ginkgo biloba L. had strong homoplasy. The phenomenon might be a survival strategy of dioecious plants under long term evolutionary pressure.

Dynamic Change Laws of Chlorophyll Fluorescence Parameters in Different Parts of Leaves of Ginkgo biloba

[Objective] The aim was to explore the dynamic change laws of chlorophyll fluorescence parameters in different parts of leaves of Ginkgo biloba.[Method] The G.biloba cultivated in North China was used as materials in this study to explore the law of daily change and ten-day change of the chlorophyll fluorescence parameters of leaves in different parts of leaves.[Result] The daily change of Fm（maximal fluorescence）,Fv（variable fluorescence）,Fv/Fm,Fm/Fo（electron transfer rate）,Fv/Fo（potential activity of PSⅡ）in leaves of G.biloba obviously presented a descending-ascending trend,the lowest value was at 12：00 and the NPQ（non-photochemical quenching）of sunny leaves arrived at the maximum at noon.The values of Fm,Fv,Fv/Fm,Fm/Fo,Fv/Fo in shade leaves of G.biloba were obviously higher than those in sunny leaves,but the peak value of NPQ of shade leaves presented earlier and higher,suggesting that the shade leaves might have more sensitive hot dissipation mechanism.Comparing to sunny leaves,shade leaves had the higher PSⅡ potential activity and inner light energy translation efficiency.[Conclusion] This study had provided theoretical basis for the protection of G.biloba resources.

Preliminary Study on Leaf Color Development and Photosynthetic Characteristics of Golden-leaf Ginkgo

[Objective]The aim of this study is to research leaf color development and photosynthetic characteristics of golden-leaf ginkgo.[Method]With one-year-old grafted seedlings of golden-leaf ginkgo as the materials,the changes of leaf color,chlorophyll content（Chl）,carotenoid（x.c）content and rate of chlorophyll and carotenoid content,as well as photosynthetic characteristics under full sunlight and overshadowing were all investigated in this study.[Result]Sprouts of golden-leaf ginkgo were pale-yellow,and changed from orange to golden in April,to light yellow-green in May,to yellow-green from June to October,to yellow in November.The chlorophyll and carotenoid contents and the rates of chlorophyll and carotenoid contents of yellow-leaf were significantly lower than that of green-leaf,while the rate of Chla/x.c and Chlb/x.c was obviously lower than the corresponding pigment content of green-leaf.During the leaf color development,Chla,Chlb and x.c content as well as the rate of Chla/x.c and Chlb/x.c of yellow-leaf ginkgo all increased.The saturation light intensity of ginkgo leaf under natural light was higher than that under overshadowing.Maximum net photosynthetic rate,light compensation point and dark respiration rate of yellow leaf were all significantly higher than that of green leaf.Chla/x.c,Chlb/x.c and Chla＋b/x.c of yellow-leaf ginkgo under overshadowing were higher than the corresponding pigment rate of leaf under natural light.[Conclusion]The best ornamental duration of golden-leaf ginkgo is April and May.The major reason for showing yellow leaf is that Chla/x.c and Chlb/x.c of yellow-leaf is obviously lower than that of green-leaf.During the leaf color development,the major reason for yellow-leaf turning to yellow-green is that the rate of Chla/x.c and Chlb/x.c increases.Chlb content of yellow-leaf under overshadowing is higher than that under natural light,which is an adaptive response to overshadowing.Chla/x.c,Chlb/x.c and Chla＋b/x.c of yellow-leaf under overshadowing are relatively higher,which is one of the reasons why yellow-leaf under overshadowing becomes yellow-green or green.

Early Development of Pollen Chamber in Ginkgo biloba Ovule

The early stage of pollen chamber development in ovule and the cytological mechanism of nucellar cell death were studied in Ginkgo biloba L. DNA ladder appearance and TUNEL assay demonstrated that the nucellar cell death, doomed to bring about pollen chamber formation, was a process of programmed cell death (PCD). A spatial distribution of PCD was visualized during the development of pollen chamber. Together with the observation under the scanning electron microscope, these results have revealed that the early developmental pattern of pollen chamber consists of four phases. Firstly, several layers of the nucellar cells at the micropylar end elongate longitudinally. Thereafter, the uppermost layer of the nucellar cells at the micropylar end initiate PCD; and the nucellar cell death extends in a basally and laterally oriented direction to form a cavity. Finally, the epidermal cells at the micropylar end detach from the other epidermis by dehiscence, bringing about the opening of the pollen chamber. The early development of pollen chamber begins sometime after the stage of megasporocyte and continues by the time of the formation of megaspore tetrad, and finally completes at the stage of development of female gametophyte. This shows a synchronous development of megaspore and pollen chamber.

Selective 3-OH Isomerization of Resibufogenin by Cell Suspension Cultures of Ginkgo biloba

Aim To modify the structure of resibufogenin by using Ginkgo bilobasuspension. Methods Young leaves of Ginkgo biloba were differentiated into callus in MS medium withonly 2,4-D as plant growth regulator. The callus was then transferred aseptically to liquid MSmedium exoge-nously supplemented with appropriate concentration of 6-BA, NAA and 2,4-D to establishsuspension cell culture system. Resibufogenin was administered into the well-grown cell cultures andincubated for 4 d. The products dissolved in the liquid phase of the cultures were extracted andpurified by silica gel column chromatography gradiently eluted with petroleum ether and acetonesystem. Results One transformed product was obtained in 40% yield after 4 d incubation, which wasidentified as 3-epi-resibufogenin on the basis of FAB MS, ~1H NMR and ^(13)C NMR spectroscopicanalysis and corresponding data reported in literature. Conclusion G. biloba suspension cultures canbe used as an enzyme system to biotransform resibufogenin, an animal-originated bufadienolide, into3-epi-resibufogenin.