Production, bioprocess optimization and anticancer activity of Camptothecin from Aspergillus terreus and Aspergillus flavus, endophytes of Ficus elastica

Bio-fabricated zinc oxide nanoparticles mediated by endophytic fungus Aspergillus sp. SA17 with antimicrobial and anticancer activities: in vitro supported by in silico studies

Introduction

In recent years, the world's attention has been drawn to antimicrobial resistance (AMR) because to the frightening prospect of growing death rates. Nanomaterials are being investigated due to their potential in a wide range of technical and biological applications.

Methods

The purpose of this study was to biosynthesis zinc oxide nanoparticles (ZnONPs) using Aspergillus sp. SA17 fungal extract, followed by characterization of the produced nanoparticles (NP) using electron microscopy (TEM and SEM), UV-analysis, X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR).

Results and Discussion

The HR-TEM revealed spherical nanoparticles with an average size of 7.2 nm, and XRD validated the crystalline nature and crystal structure features of the generated ZnONPs, while the zeta potential was 18.16 mV, indicating that the particles' surfaces are positively charged. The FT-IR was also used to identify the biomolecules involved in the synthesis of ZnONPs. The antibacterial and anticancer properties of both the crude fungal extract and its nano-form against several microbial strains and cancer cell lines were also investigated. Inhibition zone diameters against pathogenic bacteria ranged from 3 to 13 mm, while IC50 values against cancer cell lines ranged from 17.65 to 84.55 M. Additionally, 33 compounds, including flavonoids, phenolic acids, coumarins, organic acids, anthraquinones, and lignans, were discovered through chemical profiling of the extract using UPLC-QTOF-MS/MS. Some molecules, such pomiferin and glabrol, may be useful for antibacterial purposes, according to in silico study, while daidzein 4'-sulfate showed promise as an anti-cancer metabolite.

Bioprocessing of Epothilone B from Aspergillus fumigatus under solid state fermentation: Antiproliferative activity, tubulin polymerization and cell cycle analysis

Epothilone derivatives have been recognized as one of the most powerful anticancer drugs towards solid tumors, for their unique affinity to bind with β-tubulin microtubule arrays, stabilizing their disassembly, causing cell death. Sornagium cellulosum is the main source for Epothilone, however, the fermentation bioprocessing of this myxobacteria is the main challenge for commercial production of Epothilone. The metabolic biosynthetic potency of epothilone by Aspergillus fumigatus, an endophyte of Catharanthus roseus, raises the hope for commercial epothilone production, for their fast growth rate and feasibility of manipulating their secondary metabolites. Thus, nutritional optimization of A. fumigatus for maximizing their epothilone productivity under solid state fermentation process is the objective. The highest yield of epothilone was obtained by growing A. fumigatus on orange peels under solid state fermentation (2.2 μg/g), bioprocessed by the Plackett-Burman design. The chemical structure of the extracted epothilone was resolved from the HPLC and LC-MS/MS analysis, with molecular mass 507.2 m/z and identical molecular fragmentation pattern of epothilone B of S. cellulosum. The purified A. fumigatus epothilone had a significant activity towards HepG2 (IC50 0.98 μg/ml), Pancl (IC50 1.5 μg/ml), MCF7 (IC50 3.7 μg/ml) and WI38 (IC50 4.6 μg/ml), as well as a strong anti-tubulin polymerization activity (IC50 0.52 μg/ml) compared to Paclitaxel (2.0 μg/ml). The effect of A. fumigatus epothilone on the immigration ability of HepG2 cells was assessed, as revealed from the wound closure of the monolayer cells that was estimated by ~ 63.7 and 72.5%, in response to the sample and doxorubicin, respectively, compared to negative control. From the Annexin V-PI flow cytometry results, a significant shift of the normal cells to the apoptosis was observed in response to A. fumigatus epothilone by ~ 20 folds compared to control cells, with the highest growth arrest of the HepG2 cells at the G0-G1 stage.

Camptothecin bioprocessing from Aspergillus terreus, an endophyte of Catharanthus roseus: antiproliferative activity, topoisomerase inhibition and cell cycle analysis

Attenuation of camptothecin (CPT) productivity by fungi with preservation and subculturing is the challenge that halts fungi to be an industrial platform of CPT production. Thus, screening for novel endophytic fungal isolates with metabolic stability for CPT production was the objective. Catharanthus roseus is one of the medicinal plants with diverse bioactive metabolites that could have a plethora of novel endophytes with unique metabolites. Among the endophytes of C. roseus, Aspergillus terreus EFBL-NV OR131583.1 had the most CPT producing potency (90.2 μg/l), the chemical identity of the putative CPT was verified by HPLC, FT-IR, NMR and LC-MS/MS. The putative A. terreus CPT had the same molecular mass (349 m/z), and molecular fragmentation patterns of the authentic one, as revealed from the MS/MS analyses. The purified CPT had a strong activity against MCF7 (5.27 μM) and UO-31 (2.2 μM), with a potential inhibition to Topo II (IC50 value 0.52 nM) than Topo 1 (IC50 value 6.9 nM). The CPT displayed a high wound healing activity to UO-31 cells, stopping their metastasis, matrix formation and cell immigration. The purified CPT had a potential inducing activity to the cellular apoptosis of UO-31 by ~ 17 folds, as well as, arresting their cellular division at the S-phase, compared to the control cells. Upon Plackett-Burman design, the yield of CPT by A. terreus was increased by ~ 2.6 folds, compared to control. The yield of CPT by A. terreus was sequentially suppressed with the fungal storage and subculturing, losing ~ 50% of their CPT productivity by 3rd month and 5th generation. However, the productivity of the attenuated A. terreus culture was completely restored by adding 1% surface sterilized leaves of C. roseus, and the CPT yield was increased over-the-first culture by ~ 3.2 folds (315.2 μg/l). The restoring of CPT productivity of A. terreus in response to indigenous microbiome of C. roseus, ensures the A. terreus-microbiome interactions, releasing a chemical signal that triggers the CPT productivity of A. terreus. This is the first reports exploring the potency of A. terreus, endophyte of C. roseus" to be a platform for industrial production of CPT, with an affordable sustainability with addition of C. roseus microbiome.

Proteomics and metabolomics analyses of camptothecin-producing Aspergillus terreus reveal the integration of PH domain-containing proteins and peptidylprolyl cis/trans isomerase in restoring the camptothecin biosynthesis

IMPORTANCE

Decreasing the camptothecin productivity by fungi with storage and subculturing is the challenge that halts their further implementation to be an industrial platform for camptothecin (CPT) production. The highest differentially abundant proteins were Pleckstrin homology (PH) domain-containing proteins and Peptidyl-prolyl cis/trans isomerase that fluctuated with the subculturing of A. terreus with a remarkable relation to CPT biosynthesis and restored with addition of F. elastica microbiome.

Biochemical Characterization of Thermostable Acrylamide Amidohydrolase from Aspergillus fumigatus with Potential Activity for Acrylamide Degradation in Various Food Products

Acrylamide is the major by-product of the Maillard reactions in foods with the overheating processes of L-asparagine-rich foods with reducing sugars that usually allied with neurotoxicity and carcinogenicity. Several approaches have been used to prevent the formation of acrylamide, however, degrading the already formed acrylamide in foods remains unequivocal. Acrylamide hydrolyzing enzyme "amidohydrolase" is one of the most promising enzymes for acrylamide degradation in foods. So, amidohydrolase "amidase" from thermotolerant Aspergillus fumigatus EFBL was purified to their electrophoretic homogeneity by gel-filtration and ion-exchange chromatography, with overall purification folds 2.8 and yield 9.43%. The apparent molecular subunit structure of the purified A. fumigatus amidase was 50 kDa, with highest activity at reaction temperature of 40 °C and pH of 7.5 The enzyme displayed a significant thermal stability as revealed from the value of T1/2 (13.37 h), and thermal denaturation rate (Kr 0.832 × 10-3 min) at 50 °C, with metalloproteinic identity. The purified enzyme had a significant activity for acrylamide degradation in various food products such as meat, cookies, potato chips, and bread as revealed from the HPLC analysis and LC-MS analysis. So, with the purified amidase, the acrylamide in the food products was degraded by about 95% to acrylic acid, ensuring the possibility of using this enzyme in abolishing the toxic acrylamide in the foods products. This is the first report exploring the potency of A. fumigatus amidase for an actual degradation of acrylamide in foods efficiently. Further biochemical analyses are ongoing to assess the affinity of this enzyme for selective hydrolyses of acrylamide in foods, without affecting the beneficial stereochemical related compounds.

Phytochemical and metabolic profiling of the different Podocarpus species in Egypt: Potential antimicrobial and antiproliferative activities

Podocarpus is the most dominant genus of Podocarpaceae, with higher taxonomical proximity to the Taxaceae, having numerous pharmaceutical applications, however, scarce studies dealing with the physiological and metabolic criteria of Podocarpus in Egypt were reported. Thus, the objective of this work was to assess the physiological and metabolical patterns of the different species of Podocarpus; P. gracilior, P. elongates, P. macrophyllus and P. neriifolius. The highest terpenoids contents were reported in P. neriifolius, followed by P. elongatus, and P. macrophyllus. P. gracilior had the highest antioxidants amount, followed by P. macrophyllus, P. neriifolius and P. elongatus. From the GC/MS metabolic profiling, caryophyllene, β-cadinene, β-cuvebene, vitispirane, β-cadinene and amorphene were the most dominant metabolites in P. gracilior. β-Caryophyllene was the common in P. gracilior, P. elongatus, P. macrophyllus and P. neriifolius with an obvious fluctuation. The plant methanolic extracts have an obvious activity against the multidrug resistant bacteria; E. coli, P. aeruginosa, S. pyogenes and S. aureus, and fungi; A. fumigatus, A. flavus, A. niger and C. albicans in a concentration-dependent manner. The highest Taxol yield was assessed in the extracts of P. elongatus (16.4 μg/gdw), followed by P. macrophyllus, and P. neriifolius. The chemical identity of Taxol derived from P. elongatus was resolved by LC/MS, with molecular mass 854.6 m/z, and similar structural fragmentation pattern of the authentic one. The highest antitumor activity of P. elongatus extracted Taxol was assessed towards HCT-116 (30.2 μg/ml), HepG-2 (53.7 μg/ml) and MCF-7 (71.8 μg/ml). The ITS sequence of P. elongatus "as potent Taxol producer" was deposited on Genbank with accession #ON540734.1, that is the first record of Podocarpus species on Genbank.

Production, bioprocessing and antiproliferative activity of camptothecin from Aspergillus terreus, endophyte of Cinnamomum camphora: restoring their biosynthesis by indigenous microbiome of C. camphora

Fungal producing potency of camptothecin (CPT) raise the hope for their usage to be a platform for industrial production of CPT, nevertheless, attenuation of their productivity of CPT with the subculturing and preservation is the challenge. So, screening for novel endophytic fungal isolates with a reliable CPT-biosynthetic stability was the objective. Among the isolated endophytic fungi from the tested medicinal plants, Aspergillus terreus OQ642314.1, endophyte of Cinnamomum camphora, exhibits the highest yield of CPT (89.4 μg/l). From the NMR, FT-IR and LC-MS/MS analyses, the extracted CPT from A. terreus gave the same structure and molecular mass fragmentation pattern of authentic CPT (349 m/z). The putative CPT had a significant activity against MCF7 (0.27 µM) and HEPG-2 (0.8 µM), with a strong affinity to inhibits the human Topoisomerase 1 activity (IC50 0.362 μg/ml) as revealed from the Gel-based DNA relaxation assay. The purified CPT displayed a strong antimicrobial activity for various bacterial (E. coli and B. cereus) and fungal (A. flavus and A. parasiticus) isolates, ensuring the unique tertiary, and stereo-structure of A. terreus for penetrating the microbial cell walls and targeting the topoisomerase I. The higher dual activity of the purified CPT as antimicrobial and antitumor, emphasize their therapeutic efficiency, especially with growth of the opportunistic microorganisms due to the suppression of human immune system with the CPT uses in vivo. The putative CPT had an obvious activity against the tumor cell (MCF7) metastasis, and migration as revealed from the wound healing assay. The overall yield of A. terreus CPT was maximized with the Blackett-Burman design by twofolds increment (164.8 μg/l). The CPT yield by A. terreus was successively diminished with the multiple fungal subculturing, otherwise, the CPT productivity of A. terreus was restored, and increased over the zero culture upon coculturing with C. camphora microbiome (1.5% w/v), ensuring the restoring of CPT biosynthetic potency of A. terreus by the plant microbiome-derived chemical signals "microbial communication". This is the first report exploring the feasibility of A. terreus "endophyte of C. camphora" to be a preliminary platform for commercial production of CPT with a reliable sustainability upon uses of indigenous C. camphora microbiome.

Development and Optimization of Culture Medium for the Production of Glabridin by Aspergillus eucalypticola: An Endophytic Fungus Isolated from Glycyrrhiza glabra L. (Fabaceae)

Glabridin is a well-known active isoflavone found in the root of licorice (Glycyrrhiza glabra L.) that possess a wide range of biological activity. Plant cells, hairy roots, and fungal endophytes cultures are the most important alternative methods for plant resources conservation and sustainable production of natural compounds, which has received much attention in recent decades. In the present study, an efficient culture condition was optimized for the biomass accumulation and glabridin production from fungal endophyte Aspergillus eucalypticola SBU-11AE isolated from licorice root. Type of culture medium, range of pH, and licorice root extract (as an elicitor) were tested. The results showed that the highest and lowest biomass production was observed on PCB medium (6.43 ± 0.32 g/l) and peptone malt (5.85 + 0.11 g/l), respectively. The medium culture PCB was produced the highest level of glabridin (7.26 ± 0.44 mg/l), while the lowest level (4.47 ± 0.02 mg/l) was obtained from the medium peptone malt. The highest biomass (8.51 ± 0.43 g/l) and glabridin (8.30 ± 0.51 mg/l) production were observed from the PCB medium adjusted with pH = 6, while the lowest value of both traits was obtained from the same medium with pH = 7. The highest production of total glabridin (10.85 ± 0.84 mg/l) was also obtained from the culture medium treated with 100 mg/l of the plant root extract. This information can be interestingly used for the commercialization of glabridin production for further industrial applications.

Bioactive compounds and biomedical applications of endophytic fungi: a recent review

Human life has been significantly impacted by the creation and spread of novel species of antibiotic-resistant bacteria and virus strains that are difficult to manage. Scientists and researchers have recently been motivated to seek out alternatives and other sources of safe and ecologically friendly active chemicals that have a powerful and effective effect against a wide variety of pathogenic bacteria as a result of all these hazards and problems. In this review, endophytic fungi and their bioactive compounds and biomedical applications were discussed. Endophytes, a new category of microbial source that can produce a variety of biological components, have major values for study and broad prospects for development. Recently, endophytic fungi have received much attention as a source for new bioactive compounds. In addition, the variety of natural active compounds generated by endophytes is due to the close biological relationship between endophytes and their host plants. The bioactive compounds separated from endophytes are usually classified as steroids, xanthones, terpenoids, isocoumarins, phenols, tetralones, benzopyranones and enniatines. Moreover, this review discusses enhancement methods of secondary metabolites production by fungal endophytes which include optimization methods, co-culture method, chemical epigenetic modification and molecular-based approaches. Furthermore, this review deals with different medical applications of bioactive compounds such as antimicrobial, antiviral, antioxidant and anticancer activities in the last 3 years.

Physiological and metabolic traits of Taxol biosynthesis of endophytic fungi inhabiting plants: Plant-microbial crosstalk, and epigenetic regulators

Attenuating the Taxol productivity of fungi with the subculturing and storage under axenic conditions is the challenge that halts the feasibility of fungi to be an industrial platform for Taxol production. This successive weakening of Taxol productivity by fungi could be attributed to the epigenetic down-regulation and molecular silencing of most of the gene clusters encoding Taxol biosynthetic enzymes. Thus, exploring the epigenetic regulating mechanisms controlling the molecular machinery of Taxol biosynthesis could be an alternative prospective technology to conquer the lower accessibility of Taxol by the potent fungi. The current review focuses on discussing the different molecular approaches, epigenetic regulators, transcriptional factors, metabolic manipulators, microbial communications and microbial cross-talking approaches on restoring and enhancing the Taxol biosynthetic potency of fungi to be industrial platform for Taxol production.

Aspergillus terreus camptothecin-sodium alginate/titanium dioxide nanoparticles as a novel nanocomposite with enhanced compatibility and anticancer efficiency in vivo

BACKGROUND

Camptothecin derivatives are one of the most prescribed anticancer drugs for cancer patients, however, the availability, efficiency, and water solubility are the major challenges that halt the applicability of this drug.

METHODS

Biosynthetic potency of camptothecin by Aspergillus terreus, open a new avenue for commercial camptothecin production, due to their short-life span, feasibility of controlled growth conditions, and affordability for higher growth, that fulfill the availability of the scaffold of this drug.

RESULTS

Camptothecin (CPT) was purified from the filtrates of A. terreus, and their purity was checked by HPLC, and its chemical structure was verified by LC/MS, regarding to the authentic one. To improve the anticancer efficiency of A. terreus CPT, the drug was conjugated with sodium alginate (SA)/Titanium dioxide nanoparticles (TiO₂NPs) composites, and their physicochemical properties were assessed. From the FT-IR profile, a numerous hydrogen bond interactions between TiO₂ and SA chains in the SA/TiO₂ nanocomposites, in addition to the spectral changes in the characteristic bands of both SA/TiO₂ and CPT that confirmed their interactions. Transmission electron microscopy analysis reveals the spherical morphology of the developed SA/TiO₂NPs nanocomposite, with the average particle size ~ 13.3 ± 0.35 nm. From the results of zeta potential, successful loading and binding of CPT with SA/TiO₂ nanocomposites were observed.

CONCLUSION

The in vivo study authenticates the significant improvement of the antitumor activity of CPT upon loading in SA/TiO₂ nanocomposites, with affordable stability of the green synthesized TiO₂NPs with Aloe vera leaves extract.

Production and bioprocessing of camptothecin from Aspergillus terreus, an endophyte of Cestrum parqui, restoring their biosynthetic potency by Citrus limonum peel extracts

The metabolic potency of fungi as camptothecin producer elevates their prospective use as an industrial platform for commercial production, however, the loss of camptothecin productivity by fungi with the storage and subculturing are the major obstacle. Thus, screening for endophytic fungal isolates inhabiting ethnopharmacological plants with an obvious metabolic stability and sustainability for camptothecin biosynthesis could be one of the most feasible paradigms. Aspergillus terreus ON908494.1, an endophyte of Cestrum parqui was morphologically and molecularly verified, displaying the most potent camptothecin biosynthetic potency. The chemical identity of A. terreus camptothecin was confirmed from the HPLC, FTIR and LC-MS/MS analyses, gave the same molecular structure and mass fragmentation patterns of authentic one. The purified putative camptothecin displayed a strong anticancer activity towards HepG-2 and MCF-7 with IC₅₀ values 0.96 and 1.4 µM, respectively, with no toxicity to OEC normal cells. As well as, the purified camptothecin displayed a significant antifungal activity towards fungal human pathogen Candida albicans, Aspergillus flavus, and A. parasiticus, ensuring the unique structural activity relationships of A. terreus camptothecin, as a powerful dually active anticancer and antimicrobial agent. The camptothecin productivity of A. terreus was maximized by bioprocessing with Plackett-Burman design, with an overall 1.5 folds increment (170.5 µg/L), comparing to control culture. So, the optimal medium components for maximum yield of camptothecin by A. terreus was acid why (2.0 mL/L), Diaion HP20 (2.0 g/L), Amberlite XAD (2.0 g/L), dextrin (5.0 g/L), glucose (10.0 g/L), salicylic acid (2.0 g/L), serine (4.0 g/L), cysteine (4.0 g/L) and glutamate (10.0 g/L), at pH 6 for 15 days incubation. By the 5th generation of A. terreus, the camptothecin yield was reduced by 60%, comparing to zero culture. Interestingly, the productivity of camptothecin by A. terreus has been completely restored and over increased (210 µg/L), comparing to the 3^rd generation A. terreus (90 µg/L) upon addition of methanolic extracts of Citrus limonum peels, revealing the presence of some chemical signals that triggers the camptothecin biosynthetic machinery. The feasibility of complete restoring of camptothecin biosynthetic-machinery of A. terreus for stable and sustainable production of camptothecin, pave the way for using this fungal isolate as new platform for scaling-up the camptothecin production.

Production, Bioprocessing and Anti-Proliferative Activity of Camptothecin from Penicillium chrysogenum, "An Endozoic of Marine Sponge, Cliona sp.", as a Metabolically Stable Camptothecin Producing Isolate

Exploring the metabolic potency of fungi as camptothecin producers raises the hope of their usage as an industrial source of camptothecin, due to their short-life span and the feasibility of metabolic engineering. However, the tiny yield and loss of camptothecin productivity of fungi during storage and sub-culturing are challenges that counteract this approach. Marine fungi could be a novel source for camptothecin production, with higher yield and reliable metabolic sustainability. The marine fungal isolate Penicillium chrysogenum EFBL # OL597937.1 derived from the sponge "Cliona sp." has been morphologically identified and molecularly confirmed, based on the Internal Transcribed Spacer sequence, exhibiting the highest yield of camptothecin (110 μg/L). The molecular structure and chemical identity of P. chrysogenum derived camptothecin has been resolved by HPLC, FTIR and LC-MS/MS analyses, giving the same spectroscopic profiles and mass fragmentation patterns as authentic camptothecin. The extracted camptothecin displayed a strong anti-proliferative activity towards HEP-2 and HCT-116 (IC₅₀ values 0.33-0.35 µM). The yield of camptothecin was maximized by nutritional optimization of P. chrysogenum with a Plackett-Burman design, and the productivity of camptothecin increased by 1.8 fold (200 µg/L), compared to control fungal cultures. Upon storage at 4 °C as slope culture for 8 months, the productivity of camptothecin for P. chrysogenum was reduced by 40% compared to the initial culture. Visual fading of the mycelial pigmentation of P. chrysogenum was observed during fungal storage, matched with loss of camptothecin productivity. Methylene chloride extracts of Cliona sp. had the potency to completely restore the camptothecin productivity of P. chrysogenum, ensuring the partial dependence of the expression of the camptothecin biosynthetic machinery of P. chrysogenum on the chemical signals derived from the sponge, or the associated microbial flora. This is the first report describing the feasibility of P. chrysogenum, endozoic of Cliona sp., for camptothecin production, along with reliable metabolic biosynthetic stability, which could be a new platform for scaling-up camptothecin production.

Molecular and metabolic traits of some Egyptian species of Cassia L. and Senna Mill (Fabaceae-Caesalpinioideae)

The genus Cassia and Senna have been classified under subfamily Caesalpinioideae of family Fabaceae (Leguminosae) of order Fabales. There is a scarce taxonomical studies of the genus Cassia and Senna inhabiting Egyptian environments, thus, the main objective of the current was to revise and authenticate the phylogenetic relationship between studied taxa of the species of the genera Cassia and Senna in Egypt using the recent tools of ITS barcoding, RAPD analysis and metabolic profiling, in comparing to the traditional taxonomical features. From the cluster analysis of the traditional 27 morphological characters, the studied taxa were categorized into two major clades with an average taxonomic distance of 4.3. The clade I include Cassia fistula, C. renigera, C. javanica L subsp. nodosa and C. roughiia that belongs to series Obolospermae, and C. grandis that belongs to series Grandes. The clade (II) includes Senna surattensis and S. alata at taxonomic level 3.6. The taxonomical description of the studied taxa was confirmed from the molecular analysis of ITS sequences and RAPD analysis. The ITS sequences of the tested plants species C. fistula L, C. grandis MD4, C. javanica subsp. nodosa MD7, C. roxburghii MD5, C. renigera MD5 were deposited at genbank with accession numbers MW367973, MZ960447, MW386305, MW326753 and MW32685, respectively. While, the ITS sequences of the S. surrattensis and S. alata were deposited into genbank accession # MD14 MW367670 and MD20 MW412635, respectively. Thus, from the molecular analysis, two clades were clearly separated into Clade I of Cassia and Clade II of Senna. The cluster I represented by C. fistula, C. renigera, C. roxburghii, and C. javanica sub nodosa, and the cluster II represented by S. alata and S. surattensis. From the PCA of RAPD, a clearly discrimination between the two Taxa was observed revealing the characteristic grouping of Cassia and Senna. The species Senna alata and Senna surattensis were grouped together, but the species of C. renigera, C. javanica, C. roxburghii and C. grandis was grouped on a distinct group. The separation of Cassia and Senna species into two clusters verify the segregation of the genus Cassia L. senso lato into two distinct genera namely Senna P. and Cassia L. The morphological, molecular traits of the studied plants were authenticated from the metabolic profiling by GC-MS analysis. Among the 23 identified metabolites, four compounds namely hexadecanoic acid, methyl ester, 9-Octadecenoic acid (Z)-ethyl ester and Vitamin E were detected with fluctuated concentrations, among C. fistula, C. grandis, C. javanica subsp. nodosa and C. roxburghii. Conclusively, the traditional morphological features, molecular barcoding using ITS sequences, RAPD analysis and metabolic traits by GC-MS analysis, authenticates the taxonomical diversity of the genus Cassia and Senna.

Endophytic Fungi: An Effective Alternative Source of Plant-Derived Bioactive Compounds for Pharmacological Studies

Plant-associated fungi (endophytic fungi) are a biodiversity-rich group of microorganisms that are normally found asymptomatically within plant tissues or in the intercellular spaces. Endophytic fungi promote the growth of host plants by directly producing secondary metabolites, which enhances the plant's resistance to biotic and abiotic stresses. Additionally, they are capable of biosynthesizing medically important "phytochemicals" that were initially thought to be produced only by the host plant. In this review, we summarized some compounds from endophyte fungi with novel structures and diverse biological activities published between 2011 and 2021, with a focus on the origin of endophytic fungi, the structural and biological activity of the compounds they produce, and special attention paid to the exploration of pharmacological activities and mechanisms of action of certain compounds. This review revealed that endophytic fungi had high potential to be harnessed as an alternative source of secondary metabolites for pharmacological studies.

Boosting the Anticancer Activity of Aspergillus flavus "endophyte of Jojoba" Taxol via Conjugation with Gold Nanoparticles Mediated by γ-Irradiation

Taxol production by fungi is one of the promising alternative approaches, regarding to the natural and semisynthetic sources; however, the lower yield and rapid loss of Taxol productivity by fungi are the major challenges that halt their further industrial implementation. Thus, searching for fungal isolates with affordable Taxol-production stability, in addition to enhance its anticancer activity via conjugation with gold nanoparticles, is the main objectives of this study. Twenty-four endophytic fungal isolates were recovered from the barks, twigs, and leaves of jojoba plant, among these fungi, Aspergillus flavus MW485934.1 was the most potent Taxol producer (88.6 µg/l). The chemical identity of the extracted Taxol of A. flavus was verified by the TLC, HPLC, HNMR, and FTIR analyses. The yield of Taxol produced by A. flavus was optimized by the response surface methodology (RSM) using Plackett-Burman (PBD) and faced central composite designs (FCCD). The yield of Taxol by A. flavus was increased by about 3.2 folds comparing to the control cultures (from 96.5 into 302.7 µg/l). The highest Taxol yield by was obtained growing A. flavus on a modified malt extract medium (g/l) (malt extract 20.0, peptone 2.0, sucrose 20.0, soytone 2.0, cysteine 0.5, glutamine 0.5, and beef extract 1.0 adjusted to pH 6.0) and incubated at 30 °C for 16 days. From the FCCD design, the significant variables affecting Taxol production by A. flavus were cysteine, pH, and incubation time. Upon A. flavus γ-irradiation at 1.0 kGy, the Taxol yield was increased by about 1.25 fold (375.9 µg/l). To boost its anticancer activity, the purified Taxol was conjugated with gold nanoparticles (AuNPs) mediated by γ-rays irradiation (0.5 kGy), and the physicochemical properties of Taxol-AuNPs composite were evaluated by UV-Vis, DLS, XRD, and TEM analyses. The IC₅₀ values of the native-Taxol and Taxol-AuNPs conjugates towards HEPG-2 cells were 4.06 and 2.1 µg/ml, while the IC₅₀ values against MCF-7 were 6.07 and 3.3 µg/ml, respectively. Thus, the anticancer activity of Taxol-AuNPs composite was increased by 2 folds comparing to the native Taxol towards HEPG-2 and MCF-7 cell lines. Also, the antimicrobial activity of Taxol against the multidrug resistant bacteria was dramatically increased upon conjugation with AuNPs comparing to authentic AuNPs and Taxol, ensuring the higher solubility, targetability, and efficiency of Taxol upon AuNPs conjugation.

Purification and Biochemical Characterization of Taxadiene Synthase from Bacillus koreensis and Stenotrophomonas maltophilia

Taxadiene synthase (TDS) is the rate-limiting enzyme of Taxol biosynthesis that cyclizes the geranylgeranyl pyrophosphate into taxadiene. Attenuating Taxol productivity by fungi is the main challenge impeding its industrial application; it is possible that silencing the expression of TDS is the most noticeable genomic feature associated with Taxol-biosynthetic abolishing in fungi. As such, the characterization of TDS with unique biochemical properties and autonomous expression that is independent of transcriptional factors from the host is the main challenge. Thus, the objective of this study was to kinetically characterize TDS from endophytic bacteria isolated from different plants harboring Taxol-producing endophytic fungi. Among the recovered 23 isolates, Bacillus koreensis and Stenotrophomonas maltophilia achieved the highest TDS activity. Upon using the Plackett–Burman design, the TDS productivity achieved by B. koreensis (18.1 µmol/mg/min) and S. maltophilia (14.6 µmol/mg/min) increased by ~2.2-fold over the control. The enzyme was purified by gel-filtration and ion-exchange chromatography with ~15 overall folds and with molecular subunit structure 65 and 80 kDa from B. koreensis and S. maltophilia, respectively. The chemical identity of taxadiene was authenticated from the GC-MS analyses, which provided the same mass fragmentation pattern of authentic taxadiene. The tds gene was screened by PCR with nested primers of the conservative active site domains, and the amplicons were sequenced, displaying a higher similarity with tds from T. baccata and T. brevifolia. The highest TDS activity by both bacterial isolates was recorded at 37–40 °C. The Apo-TDSs retained ~50% of its initial holoenzyme activities, ensuring their metalloproteinic identity. The activity of purified TDS was completely restored upon the addition of Mg2+, confirming the identity of Mg2+ as a cofactor. The TDS activity was dramatically reduced upon the addition of DTNB and MBTH, ensuring the implementation of cysteine-reactive thiols and ammonia groups on their active site domains. This is the first report exploring the autonomous robust expression TDS from B. koreensis and S. maltophilia with a higher affinity to cyclize GGPP into taxadiene, which could be a novel platform for taxadiene production as intermediary metabolites of Taxol biosynthesis.