Submerged fermentation of Ginkgo biloba seed powder using Eurotium cristatum for the development of ginkgo seeds fermented products.

BACKGROUND: Ginkgo biloba seeds are well known for the significant curative effects on relieving cough and asthma. However, the development of products from ginkgo seeds still falls behind at present, resulting in a great waste of ginkgo seeds' resource. In this work, submerged fermentation of ginkgo seed powder using Eurotium cristatum was studied to investigate its feasibility as a new processing method. RESULTS: To promote the growth of E. cristatum, the optimum fermentation medium was 80.0 g L-1 of ginkgo seed powder with addition of 5.0 g L-1 calcium chloride (CaCl2 ), 4.0 g L-1 magnesium sulfate (MgSO4 ), 1.25 g L-1 zinc sulfate (ZnSO4 ) and 0.65 g L-1 iron(II) sulfate (FeSO4 ). The optimum fermentation conditions were pH 5.8 ± 0.1, inoculum size 5.1 × 106 CFU mL-1 , liquid medium volume 100 mL in 250-mL Erlenmeyer flask and fermentation 4 days. Through fermentation, the production of lovastatin in fermentation broth could reach up to 32.97 ± 0.17 µg mL-1 and the total antioxidant capacity was improved by more than two-fold. In addition, 40.15% of the ginkgotoxin in ginkgo seed powder was degraded while the entire degradation of ginkgolic acids was obtained. Moreover, fermented ginkgo seed powder suspension presented pleasant fragrances, and the activities of amylase and protease were enhanced to 11.30 ± 0.10 U mL-1 and 23.01 ± 0.20 U mL-1 , respectively. CONCLUSIONS: Submerged fermentation using E. cristatum could significantly enhance the functional value and safety of ginkgo seed powder, and had great potential to become a novel processing method for the development of ginkgo seeds fermented products. © 2020 Society of Chemical Industry.

Hymenobacter ginkgonis sp. nov., isolated from bark of Ginkgo biloba.

Strain HMF4947T, isolated from the bark of a ginkgo tree, was a pale-pink coloured, Gram-stain-negative, non-motile, strictly aerobic and rod-shaped bacterium. The isolate grew optimally on Reasoner's 2A agar at 30 °C, pH 7.0 and with 0 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain HMF4947T belonged to the genus Hymenobacter and was most closely related to Hymenobacter metalli A2-91T (96.9 % sequence similarity) and Hymenobacter pomorum 9-2-1-1T (96.5 %). The average nucleotide identity and estimated DNA-DNA hybridization values between strain HMF4947T and Hymenobacter arizonensis DSM 17870T were 74.3 and 20.5 %, respectively. The major fatty acids were summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), iso-C15 : 0 and C16 : 1 ω5c. The predominant isoprenoid quinone was menaquinone-7. The polar lipids comprised phosphatidylethanolamine, one unidentified aminoglycolipid, three unidentified aminophospholipids, one unidentified phospholipid, three unidentified aminolipids, two unidentified glycolipids and three unidentified polar lipids. The genomic DNA G+C content was 59.3 mol%. Thus, based on phylogenetic, phenotypic and chemotaxonomic data, strain HMF4947T represents a novel species of the genus Hymenobacter, for which the name Hymenobacter ginkgonis sp. nov. is proposed. The type strain of the species is strain HMF4947T (=KCTC 72780T=NBRC 114271T).

Community structure and diversity of the microbiomes of two microhabitats at the root-soil interface: implications of meta-analysis of the root-zone soil and root endosphere microbial communities in Xiong'an New Area.

The diversity of the microbial compositions of the root-zone soil (the rhizosphere-surrounding soil) and root endosphere (all inner root tissues) of Pinus tabulaeformis Carr. and Ginkgo biloba L. were evaluated in Xiong'an New Area using high-throughput sequencing; the influence of the soil edaphic parameters on microbial community compositions was also evaluated. Our results showed that both the taxonomic and phylogenetic diversities of the root endosphere were lower than those of the root-zone soil, but the variation in the endosphere microbial community structure was remarkably higher than that of the root-zone soil. Spearman correlation analysis showed that the soil organic matter, total nitrogen, total phosphate, total potassium, ratio of carbon to nitrogen, and pH significantly explained the α-diversity of the bacterial community and that total nitrogen differentially contributed to the α-diversity of the fungal community. Variation partitioning analysis showed that plant species had a greater influence on microbial composition variations than did any other soil property, although soil chemical parameters explained more variation when integrated. Together, our results suggest that both plant species and soil chemical parameters played a critical role in shaping the microbial community composition.

Sphingomonas ginkgonis sp. nov., isolated from phyllosphere of Ginkgo biloba.

Strain HMF7854T, isolated from a ginkgo tree, was an orange-pigmented, Gram-stain-negative, motile by means of a single flagellum, strictly aerobic, rod-shaped bacterium. The isolate grew optimally on Reasoner's 2A agar at 30 °C, pH 7.0-8.0 and 0 % NaCl. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain HMF7854T belonged to the genus Sphingomonas and was most closely related to Sphingomonasagri HKS-06T (96.8 % sequence similarity). The major fatty acids were C17 : 1 ω6c, summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The predominant isoprenoid quinone was ubiquinone-10. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, sphingoglycolipid, two unidentified lipids and two unidentified glycolipids. The genomic DNA G+C content was 68.4 mol%. Thus, based on its phylogenetic, phenotypic and chemotaxonomic data, strain HMF7854T represents a novel species of the genus Sphingomonas, for which the name Sphingomonasginkgonis sp. nov. is proposed. The type strain of the species is strain HMF7854T (=KCTC 62461T=NBRC 113337T).

Control of Foodborne Pathogenic Bacteria by Endophytic Bacteria Isolated from Ginkgo biloba L.

Endophytic bacteria (EB) are a prospective source of natural and novel bioactive compounds with pharmaceutical relevance. In the present study, a total of 50 EB were isolated from the fruits and leaves of ginkgo tree (Ginkgo biloba L.), the only living species in the division Ginkgophyta and popularly known as a living fossil. All the isolated EB were screened for their antibacterial activity against five deleterious foodborne pathogenic bacteria namely Escherichia coli ATCC 43890, Salmonella Typhimurium ATCC 19586, Bacillus cereus ATCC 10876, Listeria monocytogenes ATCC19115, and Staphylococcus aureus ATCC 12600. Among the isolated EB, GbF-96, GbF-97, and GbF-98 exhibited antibacterial activity against all the pathogenic bacteria tested, with inhibition zone ranging from 33.47 to 9.55 mm. GbF-96, identified as Bacillus subtilis, exerted the highest antibacterial activity against all the tested bacteria. In contrast, the ethyl acetate extract of GbF-96 showed antibacterial activity against only B. cereus, E. coli, and Salmonella Typhimurium. Scanning electron microscopy results indicated cracked and irregular, swollen, shrunken, and lysed cell surfaces of the pathogenic bacteria treated with ethyl acetate extract of GbF-96 or B. subtilis, indicating that the metabolites of GbF-96 might penetrate the bacterial cell membranes and evoke pathways inducing cell lysis. Together, the data suggest that B. subtilis from G. biloba can be a potential candidate for controlling dreadful foodborne pathogenic bacteria, either by itself or by its metabolites.

Changes of volatile organic compounds and bioactivity of Alternaria brassicae GL07 in different ages.

Plant endophytes are rich in secondary metabolites and are widely used in medicine, chemical, food, agriculture, and other fields. Here, an endophytic fungus is isolated from Ginkgo biloba L. leaves and identified as Alternaria brassicae GL07 through genotypic characterizations. It can produce fruity scented volatiles. The analysis of volatile organic compounds (VOCs) was done by gas chromatography-mass spectrometry. A total of 32 components were identified; and at different culture times, the composition of VOCs was different. It had more components in the first two weeks, but a fewer components on the 21st day. More olefins, ketone, aldehyde, and alcohol were found in the growth period and more amines and esters were found in the decline period. Also, 2,5-dihydroxyacetophenone, ß-ionone, and nonanal were found. They were the same ingredients in Ginkgo essential oils and some of them were isolated for the first time in the volatile constituents of endophytes. The antioxidant activity and whitening activities of all extracts were also evaluated. When cultured for 10 days, it had the strongest 2,2-diphenyl-2-picrylhydrazyl radical (IC50 , 0.56 g/L), hydroxyl radical scavenging ability (IC50 , 0.47 g/L), reducing ability, and tyrosinase inhibition ability (IC50 , 5.18 g/L), which may be due to a large amount of ketones and alcohols produced during the log phase. This demonstrates the potential of A. brassicae GL07 to produce bioactive compounds and to be used for perfume and cosmetic industries.

Streptomyces ginkgonis sp. nov., an endophyte from Ginkgo biloba.

A novel endophytic actinomycete strain, designated KM-1-2T, was isolated from seeds of Ginkgo biloba at Yangling, China. A polyphasic approach was used to study the taxonomy of strain KM-1-2T and it was found to show a range of phylogenetic and chemotaxonomic properties consistent with those of members of the genus Streptomyces. The diamino acid of the cell wall peptidoglycan was identified as LL-diaminopimelic acid. No diagnostic sugars were detected in whole cell hydrolysates. The predominant menaquinones were identified as MK-9(H6) and MK-9(H8). The diagnostic phospholipids were found to be phosphatidylethanolamine and phosphatidylcholine. The DNA G + C content of the novel strain was determined to be 72.9 mol%. The predominant cellular fatty acids (> 10.0 %) were identified as iso-C14 : 0, iso-C16 : 0, C16 : 0 and C17 : 0 cyclo. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that the strain is closely related to Streptomyces carpaticus JCM 6915T (99.3%), Streptomyces harbinensis DSM 42076T (98.9%) and Streptomyces cheonanensis JCM 14549T (98.5%). DNA-DNA hybridizations with these three close relatives gave similarity values of 39.1 ± 1.9, 35.8 ± 2.3, and 47.4 ± 2.7%, respectively, which indicated that strain KM-1-2T represents a novel species of the genus Streptomyces. This is consistent with the morphological, physiological and chemotaxonomic data. Cumulatively, these data suggest that strain KM-1-2T represents a novel Streptomyces species, for which the name Streptomyces ginkgonis sp. nov. is proposed, with the type strain KM-1-2T (= CCTCC AA2016004T = KCTC 39801T).

Arthrobacter ginkgonis sp. nov., an actinomycete isolated from rhizosphere of Ginkgo biloba L.

A Gram-stain-positive, aerobic actinobacterial strain (designated SYP-A7299T), which displayed a rod-coccus growth lifecycle, was isolated from the rhizosphere of Ginkgo biloba L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-A7299T belongs to the genus Arthrobacter and is most closely related to Arthrobacter halodurans JSM 078085T (97.4 % 16S rRNA gene sequence similarity). The DNA-DNA relatedness value between strain SYP-A7299T and A. halodurans JSM 078085T was 37 % ±2.9. The cell-wall peptidoglycan was A4α, and glucose and galactose were whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol, two glycolipids and an unknown polar lipid. The major menaquinone were MK-8(H2) (72 %) and MK-9(H2) (28 %), and the predominant cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 0. The DNA G+C content was 68.9 mol%. Based on the morphological, physiological, biochemical and chemotaxonomic characters presented in this study, strain SYP-A7299T represents a novel species of the genus Arthrobacter, for which the name Arthrobacter ginkgonis sp. nov. is proposed. The type strain is SYP-A7299T (=DSM 100491T=KCTC 39 592T).

[Genome-wide prediction and analysis of the secretory proteins and ORFs signal peptide of ginkgo endophyte KM-1-2]

Objective: Endophytes are widespread in plants and build long-term mutually beneficial symbiotic relationship with the host. However, the mechanism of their interactions with the host needs further study. To explore the mechanism of endophytic bacterium ginkgo endophyte KM-1-2, we managed to forecast its secretory proteins based on its genome and explicit characteristics. Methods: Signal peptide analysis software SignalP, transmembrane helical structure analysis software TMHMM and Phobius, cells position software PSORT, subcellar localization software TargetP and GPI anchor site analysis software big-PI Predictor were used to predict the scope of all secreted proteins, which were defined as secretome. Results: Altogether 128 typical signal peptide secretory proteins were screened out of 5299 protein sequences in KM-1-2 genome, accounting for 2.4% of the whole genome. The shortest ORF encoding these proteins is 61 bp, the longest one is 2105 bp and the average is 373 bp. The length of the signal peptide guiding secretory protein was distributed between 15 to 37 aa, with the average length of 24 aa. Amino acid with the highest present frequency of signal peptide in proper order is alanine, leucine and valine. The type of signal peptide cleavage belongs to A-X-A which named SPI cleavage type. Among the total secretory proteins 66 pieces have functional description and 26 pieces were enzymes. These enzymes mainly include glycoside hydrolase, esterase transferase, REDOX enzyme and carbon oxygen lyase. Conclusion: The predicted secretory proteins of Streptomyces lavendulae KM-1-2 were achieved through bioinformatics analysis. These secretory proteins involved some enzymes and other unknown functions. This result laid the foundation for further study between endophyte and host.

Pseudochaetosphaeronema ginkgonis sp. nov., an endophyte isolated from Ginkgo biloba.

An endophytic strain (designated as SYPF 7195T) was isolated from a branch of a ginkgo tree in Liaoning province of China. Strain SYPF 7195T was characterized by its grey to greyish-green aerial mycelium, velvety to floccose surface and swelling near the septa. Phylogenetic analyses, which were inferred from the internal transcribed spacer (ITS) and partial sequences of the LSU and SSU of the rDNA and translation elongation factor 1-alpha (TEF1), showed that strain SYPF 7195T belonged to the genus Pseudochaetosphaeronema, and was distinct from all other species with high bootstrap-supported values (92 %). Strain SYPF 7195T constitutes a separate evolutionary clade with Pseudochaetosphaeronema larense and Pseudochaetosphaeronema martinelli, with P. martinelli as its closest phylogenetic neighbour. The nucleotide differences between strain SYPF 7195T and P. martinelli were 71 substitutions in the ITS region. Strain SYPF 7195Tcould also be distinguished from P. martinelli by a number of physiological characteristics. Combined with morphology and molecular analyses, strain SYPF 7195T merits recognition as a representative of a novel species of the genus Pseudochaetosphaeronema, for which the name Pseudochaetosphaeronemaginkgonis sp. nov. is proposed. The type strain is CBS 140953T (=CGMCC 3.17865T=SYPF 7195T). The Mycobank number is MB 816567.

Nocardioides ginkgobilobae sp. nov., an endophytic actinobacterium isolated from the root of the living fossil Ginkgo biloba L.

A Gram-stain-positive, aerobic and yellow actinobacterial strain, designated SYP-A7303T, was isolated from the root of Ginkgo biloba L. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain SYP-A7303T belongs to the genus Nocardioides. The 16S rRNA gene sequence of strain SYP-A7303T showed highest similarity to Nocardioides marinus CL-DD14T ( = JCM 15615T) (98.3 %) and Nocardioides aquiterrae GW-9T ( = JCM 11813T) (97.1 %), and less than 96.9 % to the type strains of other species of the genus Nocardioides. Strain SYP-A7303T grew optimally at 28 °C, pH 7.0 and in the absence of NaCl. It contained ll-2,6-diaminopimelic acid in the cell-wall peptidoglycan, with mannose, ribose, rhamnose, glucose and galactose as whole-cell sugars. The polar lipids consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylinositol and an unknown lipid. The menaquinone was MK-8(H4) and the predominant cellular fatty acids were iso-C16 : 0, C18 : 1ω9c and C17 : 1ω8c. The DNA G+C content was 72 mol%. Mean DNA-DNA relatedness values between strain SYP-A7303T and the closely related strains N. marinus JCM 15615T and N. aquiterrae JCM 11813T were 62.5 ± 2.4 and 56.5 ± 3.5 %, respectively. Based on the morphological, physiological, biochemical and chemotaxonomic characteristics presented in this study, strain SYP-A7303T represents a novel species of the genus Nocardioides, for which the name Nocardioides ginkgobilobae sp. nov. is proposed. The type strain is SYP-A7303T ( = DSM 100492T = KCTC 39594T).

A Bilobalide-Producing Endophytic Fungus, Pestalotiopsis uvicola from Medicinal Plant Ginkgo biloba.

For screening bilobalide (BB)-producing endophytic fungi from medicinal plant Ginkgo biloba, a total of 57 fungal isolates were isolated from the internal stem, root, leaf, and bark of the plant G. biloba. Fermentation processes using BB-producing fungi other than G. biloba may become a novel way to produce BB, which is a terpene trilactones exhibiting neuroprotective effects. In this study, a BB-producing endophytic fungal strain GZUYX13 was isolated from the leaves of G. biloba grown in the campus of Guizhou University, Guiyang city, Guizhou province, China. The strain produced BB when grown in potato dextrose liquid medium. The amount of BB produced by this endophytic fungus was quantified to be 106 µg/L via high-performance liquid chromatography (HPLC), substantially lower than that produced by the host tissue. The fungal BB which was analyzed by thin layer chromatography (TLC) and HPLC was proven to be identical to authentic BB. The strain GZUYX13 was identified as Pestalotiopsis uvicola via morphology and ITS rDNA phylogeny. To the best of our knowledge, this is the first report concerning the isolation and identification of endophytic BB-producing Pestalotiopsis spp. from the host plant, which further proved that endophytic fungi have the potential to produce bioactive compounds.

Anti-phytopathogenic activity of sporothriolide, a metabolite from endophyte Nodulisporium sp. A21 in Ginkgo biloba.

Phytopathogenic fungi such as Rhizoctonia solani and Sclerotinia sclerotiorum caused multiple plant diseases resulting in severe loss of crop production. Increasing documents endorsed that endophytes are a striking resource pool for numerous metabolites with various bioactivities such as anti-fungal. Here we reported the characterization and anti-phytopathogenic activity of sporothriolide, a metabolite produced by Nodulisporium sp. A21-an endophytic fungus in the leaves of Ginkgo biloba. Among the total twenty-five endophytic fungi isolated from the healthy leaves of G. biloba, the fermentation broth (FB) of the strain A21 was found potently inhibitory activity against R. solani and S. sclerotiorum using mycelia growth inhibition method. A21 was then identified as Nodulisporium sp., the asexual stage of Hypoxylon sp., by microscopic examination and ITS rDNA sequence data comparison. Under the bioassay-guided fractionation, sporothriolide was isolated from the petroleum ether extract of the FB of A21, whose structure was established by integrated interpretation of HR-ESI-MS and (1)H- and (13)C-NMR. Furthermore, the crystal structure of sporothriolide was first reported. In addition, sporothriolide was validated to be potently antifungal against R. solani, S. sclerotiorum and inhibit conidium germination of Magnaporthe oryzae in vitro and in vivo, indicating that it could be used as a lead compound for new fungicide development.

Spatial structuring of bacterial communities within individual Ginkgo biloba trees.

Plant-associated microorganisms affect the health of their hosts in diverse ways, yet the distribution of these organisms within individual plants remains poorly understood. To address this knowledge gap, we assessed the spatial variability in bacterial community diversity and composition found on and in aboveground tissues of individual Ginkgo biloba trees. We sampled bacterial communities from > 100 locations per tree, including leaf, branch and trunk samples and used high-throughput sequencing of the 16S rRNA gene to determine the diversity and composition of these communities. Bacterial community structure differed strongly between bark and leaf samples, with bark samples harbouring much greater bacterial diversity and a community composition distinct from leaves. Within sample types, we observed clear spatial patterns in bacterial diversity and community composition that corresponded to the samples' proximity to the exterior of the tree. The composition of the bacterial communities found on trees is highly variable, but this variability is predictable and dependent on sampling location. Moreover, this work highlights the importance of carefully considering plant spatial structure when characterizing the microbial communities associated with plants and their impacts on plant hosts.

Natural phenolic metabolites from endophytic Aspergillus sp. IFB-YXS with antimicrobial activity.

Prompted by the pressing necessity to conquer phytopathogenic infections, the antimicrobial compounds were characterized with bioassay-guided method from the ethanol extract derived from the solid-substrate fermentation of Aspergillus sp. IFB-YXS, an endophytic fungus residing in the apparently healthy leave of Ginkgo biloba L. The aim of this work was to evaluate the antimicrobial activity and mechanism(s) of these bioactive compounds against phytopathogens. Among the compounds, xanthoascin (1) is significantly inhibitory on the growth of the phytopathogenic bacterium Clavibacter michiganense subsp. Sepedonicus with a minimum inhibitory concentration (MIC) value of 0.31µg/ml, which is more potent than streptomycin (MIC 0.62µg/ml), an antimicrobial drug co-assayed herein as a positive reference. Moreover, terphenyl derivatives 3, 5 and 6 are also found to be active against other phytopathogens including Xanthomonas oryzae pv. oryzae Swings, Xanthomonas oryzae pv. oryzicola Swings, Erwinia amylovora and Pseudomonas syringae pv. lachrymans etc. The antibacterial mechanism of xanthoascin (1) was addressed to change the cellular permeability of the phytopathogens, leading to the remarkable leakage of nucleic acids out of the cytomembrane. The work highlights the possibility that xanthoascin (1), an analogue of xanthocillin which is used to be an approved antibiotic, may find its renewed application as a potent antibacterial agrichemical. This study contributes to the development of new antimicrobial drugs, especially against C. michiganense subsp. Sepedonicus.

Bacillus-derived consortium enhances Ginkgo biloba's health and resistance to Alternaria tenuissima.

BACKGROUND: Bacillus, as a plant-growth-promoting rhizobacteria, can enhance the resistance of plants to phytopathogens. In our study, Bacillus strains showing excellent biocontrol were screened and used to control ginkgo leaf blight (Alternaria tenuissima). RESULTS: Four biocontrol Bacillus strains-Bsa537, Bam337, Bso544, and Bsu503-were selected from 286 isolates based on their capacity to inhibit pathogens and promote plant growth. The four Bacillus strains significantly improved the resistance of ginkgo to leaf blight. This was especially the case when the four strains were used as a mixture, which contributed to a decrease in lesion area of >40%. Hence, a mixture of Bacillus strains was used to control ginkgo leaf blight in the field. Treatment efficiency varied from 30% to 100% (average 81.5%) and was higher than that of the control (-2% to -18%, average - 8.5%); the antioxidant capacity of the treated ginkgo was also stronger. In addition, ginkgo biomass increased as a result of treatment with the Bacillus mixture, including leaf weight, area, thickness, number of lateral roots and root weight. Furthermore, the Bacillus mixture improved the ginkgo rhizosphere soil by boosting the number of beneficial microorganisms, lowering the number of pathogens and hastening soil catabolism. CONCLUSION: The Bacillus mixture improved the health status of ginkgo by protecting it from pathogen attack, promoting its growth and improving the microorganism community in the rhizosphere. This work closes a technological gap in the biological control of ginkgo leaf blight, investigates application methods for compound Bacillus biofertilizers and establishes a framework for the popularity and commercialization of these products. © 2024 Society of Chemical Industry.

Combinative effect of pulsed-light irradiation and solid-state fermentation on ginkgolic acids, ginkgols, ginkgolides, bilobalide, flavonoids, product quality and sensory assessment of Ginkgo biloba dark tea.

Pulsed light (PL) is a prospective non-thermal technology that can improve the degradation of ginkgolic acid (GA) and retain the main bioactive compounds in Ginkgo biloba leaves (GBL). However, only using PL hasn't yet achieved the ideal effect of reducing GA. Fermentation of GBL to make ginkgo dark tea (GDT) could decrease GA. Because different microbial strains are used for fermentation, their metabolites and product quality might differ. However, there is no research on the combinative effect of PL irradiation fixation and microbial strain fermentation on main bioactive compounds and sensory assessment of GDT. In this research, first, Bacillus subtilis and Saccharomyces cerevisiae were selected as fermentation strains that can reduce GA from the five microbial strains. Next, the fresh GBL was irradiated by PL for 200 s (fluences of 0.52 J/cm2), followed by B. subtilis, S. cerevisiae, or natural fermentation to make GDT. The results showed that compared with the control (unirradiated and unfermented GBL) and the only PL irradiated GBL, the GA in GDT using PL + B. subtilis fermentation was the lowest, decreasing by 29.74%; PL + natural fermentation reduced by 24.53%. The total flavonoid content increased by 14.64% in GDT using PL + B. subtilis fermentation, whose phenolic and antioxidant levels also increased significantly. Sensory evaluation showed that the color, aroma, and taste of the tea infusion of PL + B. subtilis fermentation had the highest scores. In conclusion, the combined PL irradiation and solid-state fermentation using B. subtilis can effectively reduce GA and increase the main bioactive compounds, thus providing a new technological approach for GDT with lower GA.

The Antiphytopathogenic Metabolites and the Synergy of Endophytes Paraphaeosphaeria sp., Nigrospora oryzae from the Same Ginkgo biloba Host.

Two endophytes from the same Ginkgo biloba host were isolated and cultured separately. Three new eremophilane sesquiterpenoids (1-3), three new furan derivates (6, 8-9), one new polyketide (10), and four known compounds (4, 5, 7, 11) from Paraphaeosphaeria sp. and two new 10-membered macrolides (12-13), a new liner polyketide (14), a new benzofuran (15), and six known compounds (16-21) from Nigrospora oryzae were isolated. The structures of the isolated compounds were determined by spectroscopic methods, NMR calculations, and ECD calculations. The compounds 3-7, 9-10, 12, and 14-17 showed significant antiphytopathogenic effects against mycotoxigenic Alternaria sp. comparable to the activity of nystatin (positive control). Compounds 2, 6, 8, 9, and 18 indicated inhibitions against phytopathogen Fusarium asiaticum with MICs < 10 µg/mL. In addition, the compounds with weak antifungal activities from two endophytes were mixed to test their antifungal activity. The results showed that the metabolites from two endophytes had synergistic antifungal effects, and the beneficial interactions between natural products can induce more antifungal effects against plant pathogens than that of single compounds.

Flavipin in Chaetomium globosum CDW7, an endophytic fungus from Ginkgo biloba, contributes to antioxidant activity.

1,2-Benzenedicarboxaldehyde-3,4,5-trihydroxy-6-methyl (flavipin) was found to be antagonistic against nematodes and fungi. Here we demonstrated that flavipin is a potent antioxidant in vitro and in vivo, which has great potential in the therapy for free radical-associated diseases. Therefore, flavipin-producing bio-source was screened from 80 endophytes in Ginkgo biloba. Seven endophytic fungi were able to synthesize antioxidant substances and identified by ITS rDNA sequences. Among them, Chaetomium globosum CDW7 was a remarkable producer of flavipin. The fermentation parameters of CDW7 were then optimized for high flavipin production. Cultured under the optimal condition (25 °C, 100/250 mL flask, 12 discs/flask, 150 rpm, pH 6.5) for 14 days, CDW7 was able to synthesize flavipin at a production of 315.5 mg/L. In addition, flavipin output was positively correlated to antioxidant activities of crude extracts with a correlation coefficient of 0.8235, indicating that flavipin was the major antioxidant component of CDW7's metabolites. These data demonstrated that CDW7 was a highly yielded bio-source of antioxidant flavipin.

New flavonol and diterpenoids from the endophytic fungus Aspergillus sp. YXf3.

One new flavonol, chlorflavonin A (1), four new diterpenoids, aspergiloids E-H (3, 5-7), together with eight known compounds (2, 4, 8-13) were isolated from solid fermentation of Aspergillus sp. (strain no. YXf3), an endophytic fungus from Ginkgo biloba. Their structures were determined through detailed spectroscopic analysis combined with comparison of NMR spectra data with reported ones. All of them were screened on cytotoxicity against KB, SGC-7901, SW1116, and A549 cell lines; compounds 4, 9-11 exhibited moderate activities with IC50 values ranging from 6.74 to 46.64 µM.