Cyclosporin A--a review on fermentative production, downstream processing and pharmacological applications

Cyclosporine-induced alopecia:a case report, FDA adverse event reporting system analysis and literature assessment

Cyclosporine is a potent immunosuppressive drug for various immune-mediated diseases in children. Cyclosporine's expected therapeutic effect also carries a wide range of side effects. One of the most common and intriguing dermatological side effects is hypertrichosis. However, recent reports have recognized alopecia as a potential adverse effect of cyclosporine. Here, we report a case of a 29-month-old boy diagnosed with aplastic anemia. During cyclosporine therapy, the patient presented with hair loss on the scalp, which and subsequently spread to the eyebrows and eyelashes. The alopecic symptoms were not relieved following topical minoxidil liniment interventions. When the cyclosporine was discontinued, a remarkable improvement was observed in the scalp, with complete hair regrowth. Data concerning cyclosporine from the FDA Adverse Event Reporting System (FAERS) database were extracted from January 2004 to January 2023. Within FAERS, our post-marketing pharmacovigilance analysis detected the reporting association of cyclosporine and alopecia. In monotherapy, cyclosporine-induced alopecia was observed in 118 cases, and tacrolimus-induced alopecia signals were detected in 197 cases. Although the potential mechanism of medication-induced hair loss is unclear, we identified a potential correlation between alopecia and cyclosporine, and it is still necessary to adequately recognize and clinically monitor this paradoxical reaction.

The effect of Ca2+-calcineurin signaling pathway on the antifungal activity of Pd-D-V against Botrytis cinerea

Gray mold, caused by Botrytis cinerea is an intractable fungal disease that causes extensive damage to agricultural products. In the search for novel antifungal active ingredients, we discovered a linear pyranocoumarin Pd-D-V was effective against B. cinerea in both in vitro and in vivo assays. Furthermore, this study investigated the effects of Ca2+ and the Ca2+-calcineurin signaling pathway on its antifungal activity against B. cinerea. The results indicated that Pd-D-V reduced the concentration of Ca2+ in the mycelia of B. cinerea; CaCl2, the Ca2+ channel blocker verapamil, or the calcineurin inhibitor cyclosporin A could affect the sensitivity of Pd-D-V against B. cinerea; the expression of genes (Bccch1, Bcmid1, BccnA, Bccnb1, Bcpmc1, and Bcpmr1) of the Ca2+-calcineurin signaling pathway decreased after Pd-D-V treatment. In summary, Pd-D-V is compound for developing fungicides against B. cinerea. Pd-D-V can reduce intracellular Ca2+ concentration and disturb Ca2+ homeostasis. The Ca2+-calcineurin signaling pathway is important in the antifungal activity of Pd-D-V against B. cinerea.

Interventional Effect of Donkey Bone Collagen Peptide Iron Chelate on Cyclophosphamide Induced Immunosuppressive Mice

Immunodeficiency can disrupt normal physiological activity and function. In this study, donkey bone collagen peptide (DP) and its iron chelate (DPI) were evaluated their potential as immunomodulators in cyclophosphamide (Cytoxan®, CTX)-induced Balb/c mice. The femoral tissue, lymphocytes, and serum from groups of mice were subjected to hematoxylin and eosin (H&E) staining, methylthiazolyldiphenyl-tetrazolium bromide (MTT) cell proliferation assays, and enzyme-linked immunosorbent assay (ELISA), respectively. Furthermore, a non-targeted metabolomics analysis based on UPLC-MS/MS and a reverse transcription polymerase chain reaction (RT-qPCR) technology were used to explore the specific metabolic pathways of DPI regulating immunocompromise. The results showed that CTX was able to significantly reduce the proliferative activity of mouse splenic lymphocytes and led to abnormal cytokine expression. After DP and DPI interventions, bone marrow tissue damage was significantly improved. In particular, DPI showed the ability to regulate the levels of immune factors more effectively than Fe2+ and DP. Furthermore, metabolomic analysis in both positive and negative ion modes showed that DPI and DP jointly regulated the levels of 20 plasma differential metabolites, while DPI and Fe2+ jointly regulated 14, and all 3 jointly regulated 10. Fe2+ and DP regulated energy metabolism and pyrimidine metabolism pathways, respectively. In contrast, DPI mainly modulated the purine salvage pathway and the JAK/STAT signaling pathway, which are the key to immune function. Therefore, DPI shows more effective immune regulation than Fe2+ and DP alone, and has good application potential in improving immunosuppression.

New Cyclic Pentapeptides from the Mangrove-Derived Aspergillus fumigatus GXIMD 03099

Four new cyclic pentapeptides, avellanins D-G (1-4), together with four known compounds (5-8), were isolated from a mangrove-derived Aspergillus fumigatus GXIMD 03099 fungus from Acanthus ilicifolius L. Their structures were elucidated by analysis of HRESIMS, NMR, and ESI-MS/MS data. Their absolute configurations were determined by X-ray diffraction analysis and Marfey's method. Compounds 1-8 were screened for insecticidal and antibacterial activities. Compound 2 showed insecticidal activity against newly hatched larvae of Culex quinquefasciatus with an LC50 value of 86.6 µM; compound 4 had weak activity against Vibrio harveyi with an MIC value of 5.85 µM.

Resveratrol attenuates cyclosporin A-induced upregulation of the thromboxane A2 receptor and hypertension via the AMPK/SIRT1 and MAPK/NF-κB pathways in the rat mesenteric artery

Cyclosporin A, an immunosuppressive agent, is extensively utilized for the prevention of transplant rejection and treat autoimmune disease in the clinic, despite its association with a high risk of hypertension development among patients. Resveratrol is a kind of non-flavonoid phenolic compound that widely exists in many plants. The aim of the present study was to investigate the mechanism by which resveratrol ameliorates cyclosporin A-induced hypertension. The arterial rings of the mesentery were incubated with cyclosporin A and resveratrol in vitro. Rats were administered cyclosporin A and/or resveratrol for 3 weeks in vivo. Blood pressure was measured via the tail arteries. Vasoconstriction curves were recorded using a sensitive myograph. The protein expression was evaluated through Western blotting. This study demonstrated that resveratrol mitigated the cyclosporin A-induced increase in blood pressure in rats. Furthermore, resveratrol markedly inhibited the cyclosporin A-induced upregulation of thromboxane A2 receptor-mediated vasoconstriction in the rat mesenteric artery both in vitro and in vivo. Moreover, resveratrol activated AMPK/SIRT1 and inhibited the MAPK/NF-κB signaling pathway. In conclusion, resveratrol restored the cyclosporin A-induced upregulation of the thromboxane A2 receptor and hypertension via the AMPK/SIRT1 and MAPK/NF-κB pathways in rats.

LC-MS/MS and EMIT measure the whole blood concentration of cyclosporine A: The two methods yield concordant results within the dynamic range of the latter, but the former shows broader application scenarios

Cyclosporine A (CsA) is a widely used immunosuppressive drug with a narrow therapeutic index and large individual differences. Its therapeutic and toxic effects are closely related to blood drug concentrations, requiring routine therapeutic drug monitoring (TDM). The current main methods for TDM of CsA are enzyme multiplied immunoassay technique (EMIT) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). However, few study on the method comparison of the EMIT and LC-MS/MS for the measurement of whole blood CsA concentration in children has been reported. In this study, we developed a simple and sensitive LC-MS/MS assay for the determination of CsA, and 657 cases of CsA concentrations were determined from 197 pediatric patients by a routine EMIT assay and by the validated in-house LC-MS/MS method on the same batch of samples, aimed to address the aforementioned concern. Consistency between the two assays was evaluated using linear regression and Bland-Altman analysis. The linear range of LC-MS/MS was 0.500-2000 ng/mL and that of the EMIT was 40-500 ng/mL, respectively. Overall, the correlation between the two methods was significant (r-value ranging from 0.8842 to 0.9441). Unsatisfactory consistency was observed in the concentrations < 40 ng/mL (r = 0.7325) and 200-500 ng/mL (r = 0.6851). Bland-Altman plot showed a mean bias of -18.0 % (±1.96 SD, -73.8 to 37.8 %) between EMIT and LC-MS/MS. For Passing-Bablok regression between EMIT and LC-MS/MS did not differ significantly (p > 0.05). In conclusion, the two methods were closely correlated, but the CsA concentration by LC-MS/MS assay was slightly higher than that by EMIT method. Switching from the EMIT assay to the LC-MS/MS method was acceptable, and the LC-MS/MS method will receive broader application in clinical settings due to its better analytical capabilities, but the results need to be further verified in different laboratories.

Enhancing cancer therapy: The role of drug delivery systems in STAT3 inhibitor efficacy and safety

The signal transducer and activator of transcription 3 (STAT3), a member of the STAT family, resides in the nucleus to regulate genes essential for vital cellular functions, including survival, proliferation, self-renewal, angiogenesis, and immune response. However, continuous STAT3 activation in tumor cells promotes their initiation, progression, and metastasis, rendering STAT3 pathway inhibitors a promising avenue for cancer therapy. Nonetheless, these inhibitors frequently encounter challenges such as cytotoxicity and suboptimal biocompatibility in clinical trials. A viable strategy to mitigate these issues involves delivering STAT3 inhibitors via drug delivery systems (DDSs). This review delineates the regulatory mechanisms of the STAT3 signaling pathway and its association with cancer. It offers a comprehensive overview of the current application of DDSs for anti-STAT3 inhibitors and investigates the role of DDSs in cancer treatment. The conclusion posits that DDSs for anti-STAT3 inhibitors exhibit enhanced efficacy and reduced adverse effects in tumor therapy compared to anti-STAT3 inhibitors alone. This paper aims to provide an outline of the ongoing research and future prospects of DDSs for STAT3 inhibitors. Additionally, it presents our insights on the merits and future outlook of DDSs in cancer treatment.

The biosynthetic logic and enzymatic machinery of approved fungi-derived pharmaceuticals and agricultural biopesticides

Covering: 2000 to 2023The kingdom Fungi has become a remarkably valuable source of structurally complex natural products (NPs) with diverse bioactivities. Since the revolutionary discovery and application of the antibiotic penicillin from Penicillium, a number of fungi-derived NPs have been developed and approved into pharmaceuticals and pesticide agents using traditional "activity-guided" approaches. Although emerging genome mining algorithms and surrogate expression hosts have brought revolutionary approaches to NP discovery, the time and costs involved in developing these into new drugs can still be prohibitively high. Therefore, it is essential to maximize the utility of existing drugs by rational design and systematic production of new chemical structures based on these drugs by synthetic biology. To this purpose, there have been great advances in characterizing the diversified biosynthetic gene clusters associated with the well-known drugs and in understanding the biosynthesis logic mechanisms and enzymatic transformation processes involved in their production. We describe advances made in the heterogeneous reconstruction of complex NP scaffolds using fungal polyketide synthases (PKSs), non-ribosomal peptide synthetases (NRPSs), PKS/NRPS hybrids, terpenoids, and indole alkaloids and also discuss mechanistic insights into metabolic engineering, pathway reprogramming, and cell factory development. Moreover, we suggest pathways for expanding access to the fungal chemical repertoire by biosynthesis of representative family members via common platform intermediates and through the rational manipulation of natural biosynthetic machineries for drug discovery.

What is the role of microbial biotechnology and genetic engineering in medicine?

Microbial products are essential for developing various therapeutic agents, including antibiotics, anticancer drugs, vaccines, and therapeutic enzymes. Genetic engineering techniques, functional genomics, and synthetic biology unlock previously uncharacterized natural products. This review highlights major advances in microbial biotechnology, focusing on gene-based technologies for medical applications.

Applications of topical immunomodulators enhance clinical signs of vernal keratoconjunctivitis (VKC) and atopic keratoconjunctivitis (AKC): a meta-analysis

PURPOSE

This meta-analysis aimed to review the safety and efficacy of topical cyclosporine A (CsA) and topical tacrolimus in allergic eye disease.

METHODS

A systematic search identified thirteen studies and a total of 445 patients for inclusion, making this the largest meta-analysis published on the subject. The current review was performed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA).

RESULTS

Thirteen randomized control trials were included in the meta-analysis. Eleven studies used CsA as the treatment, and two used Tacrolimus. In total, 445 participants were included, of whom 76.6% were male. The mean age of participants across the included studies was 14 years. All studies reported clinical signs as evaluated by an examining clinician. Signs were usually assessed by anatomical region, with the most common regions being the conjunctiva and the cornea, and the most common signs assessed were hyperemia and papillae. Three studies accounted for more than 50% of the meta-analysis's weight. Effect size (d) ranged from - 2.37 to - 0.03, negative values favoring immunomodulators. Fixed Effect Meta-Analysis returned an SMD of - 0.81 (95% CI [- 0.98, - 0.65]). However, there was significant heterogeneity (I2 = 61%, Qw = 30.76) in the outcome measure (P = 0.0021); therefore, a random-effect meta-analysis was also completed in which the pooled SMD was - 0.98 (95% CI [- 1.26, - 0.69], τ2 = 0.16).

CONCLUSIONS

This study affirms the current scientific community's stance that immunomodulators effectively treat clinical signs, including blepharitis, conjunctival hyperemia, edema, papillae, and corneal damage in severe ocular allergic disease.

Exploring the Effects of Cyclosporin A to Isocyclosporin A Rearrangement on Ion Mobility Separation

Cyclosporin A (CycA) is a peptide secondary metabolite derived from fungi that plays a crucial role in transplantation surgery. Cyclic traveling wave ion mobility mass spectrometry (IM-MS) revealed an N → O peptidyl shift in singly protonated CycA to isocyclosporin A (isoA), whereas no such isomerization was observed for doubly protonated and sodiated molecules. CycA and isoA were able to be separated by considering doubly protonated precursors using a specific ion fragment. In parallel, sodium ion stabilization facilitated the simultaneous separation and quantitation of singly charged cyclosporin isomers with the limit of detection and coefficient of determination of 1.3% and 0.9908 for CycA in isoA and 1.0% and 0.9830 for isoA in CycA, respectively. Finally, 1H-13C gHSQC NMR experiments permitted parallel recording of up to 11 cyclosporin conformers. The ratios were determined by integrating the volume of cross-peaks of the upfield resonating hydrogen in the diastereotopic methylene group of sarcosine-3.

Progress in approved drugs from natural product resources

Natural products (NPs) have consistently played a pivotal role in pharmaceutical research, exerting profound impacts on the treatment of human diseases. A significant proportion of approved molecular entity drugs are either directly derived from NPs or indirectly through modifications of NPs. This review presents an overview of NP drugs recently approved in China, the United States, and other countries, spanning various disease categories, including cancers, cardiovascular and cerebrovascular diseases, central nervous system disorders, and infectious diseases. The article provides a succinct introduction to the origin, activity, development process, approval details, and mechanism of action of these NP drugs.

Comparative proteomics reveals the mechanism of cyclosporine production and mycelial growth in Tolypocladium inflatum affected by different carbon sources

Cyclosporine A (CsA) is a secondary cyclopeptide metabolite produced by Tolypocladium inflatum that is widely used clinically as an immunosuppressant. CsA production and mycelial growth differed when T. inflatum was cultured in different carbon source media. During early fermentation, CsA was preferred to be produced in fructose medium, while the mycelium preferred to accumulate in sucrose medium. On the sixth day, the difference was most pronounced. In this study, high-throughput comparative proteomics methods were applied to analyze differences in protein expression of mycelial samples on day 6, revealing the proteins and mechanisms that positively regulate CsA production related to carbon metabolism. The differences included small molecule acid metabolism, lipid metabolism, organic catabolism, exocrine secretion, CsA substrate Bmt synthesis, and transcriptional regulation processes. The proteins involved in the regulation of mycelial growth related to carbon metabolism were also revealed and were associated with waste reoxidation processes or coenzyme metabolism, small molecule synthesis or metabolism, the stress response, genetic information or epigenetic changes, cell component assembly, cell wall integrity, membrane metabolism, vesicle transport, intramembrane localization, and the regulation of filamentous growth. This study provides a reliable reference for CsA production from high-efficiency fermentation. This study provides key information for obtaining more CsA high-yielding strains through metabolic engineering strategies.

Cis-trans isomerization in cyclosporin C dissolved in acetonitrile

Cyclosporin is an 11-amino acid cyclic peptide with pharmacologically valuable properties which has a variety of actual and potential applications. Its activity relies on the cell membrane permeability which, in turn, depends on the structure of cyclosporin and its ability to change the conformation. In this work, conformational exchange processes occurring in cyclosporin C were studied using one- and two-dimensional nuclear magnetic resonance spectroscopy. The free energy barrier separating two major conformers observed in polar solution (acetonitrile) was found to be 77 ± 2 kJ/mol. Less populated conformation states are also present in the solution, which agrees with the ease of formation of multiple forms revealed by MD simulations of cyclosporin C.

Codeine dysregulates ribosome biogenesis in Escherichia coli with DNA double-strand breaks to chart path to new classes of antibiotics

Aim

A bacterial genetics-guided approach was utilized for the discovery of new compounds affecting bacterial genome stability.

Materials & methods

Fungal extracts and fractions were tested for genome instability-mediated antibacterial activity. Interaction assays and RT-qPCR were used to identify compounds that boost the activity of sub-minimum inhibitory concentration streptomycin and obtain insights on the molecular mechanisms of the primary hit compound, respectively.

Results

Several extracts and fractions caused bacterial genome instability. Codeine, in synergy with streptomycin, regulates double-strand break (DSB) repair and causes bacterial ribosome dysfunction in the absence of DSBs, and dysregulation of ribosome biogenesis in a DSB-dependent manner.

Conclusion

This study demonstrates a potential viable strategy that we are exploring for the discovery of new chemical entities with activities against Escherichia coli and other bacterial pathogens.

Synthetic Approaches to the New Drugs Approved During 2021

Each year, new drugs are introduced to the market, representing structures that have affinity for biological targets implicated in human diseases and conditions. These new chemical entities (NCEs), particularly small molecules and antibody-drug conjugates, provide insight into molecular recognition and serve as potential leads for the design of future medicines. This annual review is part of a continuing series highlighting the most likely process-scale synthetic approaches to 35 NCEs that were first approved anywhere in the world during 2021.

Molecular Phylogeny and Morphology of Tolypocladium globosum sp. nov. Isolated from Soil in Korea

In this study, fungal strains designated as KNUF-22-14A and KNUF-22-15A were isolated from soil samples in Korea. These two strains were identified based on cultural and morphological characteristics as well as phylogenetic analyses and were found to be morphologically and phylogenetically identical. Upon their morphological comparison with closely related species, such as Tolypocladium album, T. amazonense, T. endophyticum, T. pustulatum, and T. tropicale, a difference in the size of short phialides [0.6-2.4(-9.3) × 0.8-1.4 µm] was observed. Meanwhile, these strains had larger conidia (1.2-3.0 × 1.2-3.0 µm) than T. album, T. amazonense, T. endophyticum, and T. tropicale and smaller conidia than T. pustulatum. Phylogenetic analyses using a multi-locus datasets based on ITS, LSU, and SSU showed that KNUF-22-14A and KNUF-22-15A formed a distinct cluster from previously identified Tolypocladium species. Thus, these fungal strains isolated from soil in Korea are proposed as a novel species according to their characteristics and are named Tolypocladium globosum sp. nov.

Cytotoxic Cyclodepsipeptides and Cyclopentane Derivatives from a Plant-Associated Fungus Fusarium sp

In this work, four new cyclodepsipeptides, fusarihexins C-E (1-3) and enniatin Q (4), four new cyclopentane derivatives, fusarilins A-D (5-8), together with eight known compounds (9-16), were isolated from cultures of the endophytic fungus Fusarium sp. The structures of the isolated compounds were elucidated by analysis of HRMS and NMR spectroscopic data. The absolute configurations were determined using Marfey's method, a modified Mosher's method, single-crystal X-ray diffraction analysis, and ECD analysis. The antitumor activities of the isolated compounds in vitro were evaluated. Cyclodepsipeptides displayed cytotoxicities against the Huh-7, MRMT-1, and HepG-2 cell lines. Compounds 4, 9, 10, and 12 with IC₅₀ values of 1.0-9.1 μM exhibited the most potent cytotoxicities against the three cell lines as compared to the positive control-5-fluorouracil. Compounds 1-3 and 11 exhibited moderate cytotoxic activities (IC₅₀ values of 10.7-20.1 μM).

Valorization of Cheese Whey as a Feedstock for Production of Cyclosporin A by Tolypocladium inflatum

Food waste-based biorefineries are considered an essential concept for the implementation of a sustainable circular economy. In this study, cheese whey powder (CWP), a dairy industry waste, was utilized to produce cyclosporin A (CsA). As it is difficult to valorize CWP because its components vary depending on the origin, a process for sugar conversion via acid hydrolysis was designed to obtain reproducible results using refined whey powder (WP) of a consistent quality. Acid hydrolysis was carried out using 2% (w/w) HCl and biomass loading of 50 g/L at 121 °C for 20 min. CWP hydrolysates were utilized to ferment Tolypocladium inflatum ATCC 34921. CsA production was found to be 51.3 mg/L at 12 days, a 1.4-fold increase compared to the control (commercial glucose, 36.3 mg/L). Our results showed that 100 g CWP can be converted to 81.8 mg of CsA. This finding demonstrated that CWP can be used as a sustainable feedstock for biorefineries.

Transcriptomics and Metabolomics Analysis of Sclerotium rolfsii Fermented with Differential Carbon Sources

Scleroglucan is obtained from Sclerotium rolfsii and is widely used in many fields. In this study, transcriptomics combined with metabolomics were used to study the global metabolites and gene changes. The results of the joint analysis showed that the DEGs (differentially expressed genes) and DEMs (differentially expressed metabolites) of SEPS_48 (fermented with sucrose as a carbon source for 48 h) and GEPS_48 (fermented with glucose as a carbon source for 48 h) comparison groups were mainly related to cell metabolism, focusing on carbohydrate metabolism, amino acid metabolism, and amino sugar and nucleoside sugar metabolism. We therefore hypothesized that the significant differences in these metabolic processes were responsible for the differences in properties. Moreover, the joint analysis provides a scientific theoretical basis for fungal polysaccharides biosynthesis and provides new insights into the effects of carbon sources on the production. As an excellent bioenergy and biological product, scleroglucan can be better applied in different fields, such as the food industry.

Phylogeny and Systematics of the Genus Tolypocladium (Ophiocordycipitaceae, Hypocreales)

The taxonomy and phylogeny of the genus Tolypocladium are herein revised based on the most comprehensive dataset to date. Two species-level phylogenies of Tolypocladium were constructed: a single-gene phylogeny (ITS) of 35 accepted species and a multigene phylogeny (nrSSU, nrLSU, tef-1α, rpb1, and rpb2) of 27 accepted species. Three new species, Tolypocladium pseudoalbum sp. nov., Tolypocladium subparadoxum sp. nov., and Tolypocladium yunnanense sp. nov., are described in the present study. The genetic divergences of four markers (ITS, tef-1α, rpb1 and rpb2) among Tolypocladium species are also reported. The results indicated that species of Tolypocladium were best delimited by rpb1 sequence data, followed by the sequence data for the rpb2, tef-1α, and ITS provided regions. Finally, a key to the 48 accepted species of Tolypocladium worldwide is provided.

Evolutionary relationships of adenylation domains in fungi

Non-ribosomal peptide synthetases (NRPSs) and NRPS-like enzymes are abundant in microbes as they are involved in the production of primary and secondary metabolites. In contrast to the well-studied NRPSs, known to produce non-ribosomal peptides, NRPS-like enzymes exhibit more diverse activities and their evolutionary relationships are unclear. Here, we present the first in-depth phylogenetic analysis of fungal NRPS-like A domains from functionally characterized pathways, and their relationships to characterized A domains found in fungal NRPSs. This study clearly differentiated amino acid reductases, including NRPSs, from CoA/AMP ligases, which could be divided into 10 distinct phylogenetic clades that reflect their conserved domain organization, substrate specificity and enzymatic activity. In particular, evolutionary relationships of adenylate forming reductases could be refined and explained the substrate specificity difference. Consistent with their phylogeny, the deduced amino acid code of A domains differentiated amino acid reductases from other enzymes. However, a diagnostic code was found for α-keto acid reductases and clade 7 CoA/AMP ligases only. Comparative genomics of loci containing these enzymes revealed that they can be independently recruited as tailoring genes in diverse secondary metabolite pathways. Based on these results, we propose a refined and clear phylogeny-based classification of A domain-containing enzymes, which will provide a robust framework for future functional analyses and engineering of these enzymes to produce new bioactive molecules.

Cyclosporin A as a Potential Insecticide to Control the Asian Corn Borer Ostrinia furnacalis Guenée (Lepidoptera: Pyralidae)

The long-term use of chemical insecticides has caused serious problems of insect resistance and environmental pollution; new insecticides are needed to solve this problem. Cyclosporin A (CsA) is a polypeptide produced by many fungi, which is used to prevent or treat immune rejection during organ transplantation. However, little is known about the utility of CsA as an insecticide. Therefore, this study evaluated the insecticidal activity of CsA using Ostrinia furnacalis as a model. The results demonstrated that CsA was toxic to O. furnacalis with LC₅₀ values of 113.02 μg/g and 198.70 μg/g for newly hatched neonates and newly molted third-instar larvae, respectively. Furthermore, CsA treatment had sublethal effects on the development of O. furnacalis, and significantly reduced the fecundity of adults; this suggests that CsA has great potential to suppress O. furnacalis populations. Further analysis revealed that CsA suppressed calcineurin activity in larvae. CsA had independent or synergistic toxic effects on O. furnacalis when combined with β-cypermethrin, indoxacarb, emamectin benzoate, azadirachtin, and the Bacillus thuringiensis toxin Cry1Ac, which suggests that CsA can help prevent or manage resistance. Our study provides detailed information on the potential of CsA as an insecticide for controlling lepidopterans.

Identification of PKS-NRPS Hybrid Metabolites in Marine-Derived Penicillium oxalicum

Filamentous fungi are abundant resources of bioactive natural products. Here, 151 marine-derived fungi were collected from the north Yellow Sea and identified by an internal transcribed spacer (ITS) sequence. The crude extracts of all strains were evaluated for their antimicrobial activities and analyzed by HPLC fingerprint. Based on these, strain Penicillium oxalicum MEFC104 was selected for further investigation. Two new polyketide–amino acid hybrid compounds with feature structures of tetramic acid, oxopyrrolidine A and B, were isolated. Their planner structures were assigned by HRESIMS and 1D/2D NMR experiments. The absolute configurations were determined by modified Mosher’s method, J-based configuration analysis, and ECD calculations. Furthermore, the biosynthetic pathway was identified by bioinformatic analysis and gene-deletion experiments. This study established a link between oxopyrrolidines and the corresponding biosynthesis genes in P. oxalicum.

Chemical mutagenesis and high throughput media optimization in Tolypocladium inflatum MTCC-3538 leads to enhanced production of cyclosporine A

Diethyl sulphate-based mutagenesis was performed on fungal strain Tolypocladium inflatum MTCC-3538. Two mutant morphotypes MT1-3538 and MT2-3538 were selected for further chemo-profiling studies. LCMS/MS profiling of fungal crude extract confirmed that the wild-type and mutant strains (MT1-3538, MT2-3538) were competent to produce cyclosporine A. MT2-3538 produced 2.1 fold higher cyclosporine A in comparison to the wild type. Further, LCMS-based high throughput media optimization was performed for MT2-3538 in 20 different media combinations to increase cyclosporine A yield. On the basis of ion-intensity profiling, media combination consisting of Glucose 0.1 g/L; Peptone 0.005 g/L and Valine 0.005 g/L was selected and used for up-scaling purpose. Mutant MT2-3538 with optimized media combination increased cyclosporine yield 16 fold and could potentially be exploited for commercial outcomes.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03219-x.

Tolypocladamide H and the Proposed Tolypocladamide NRPS in Tolypocladium Species

The genome of entomopathogenic fungus Tolypocladium inflatum Gams encodes 43 putative biosynthetic gene clusters for specialized metabolites, although genotype-phenotype linkages have been reported only for the cyclosporins and fumonisins. T. inflatum was cultured in defined minimal media, supplemented with or without one of nine different amino acids. Acquisition of LC-MS/MS data for molecular networking and manual analysis facilitated annotation of putative known and unknown metabolites. These data led us to target a family of peptaibols and guided the isolation and purification of tolypocladamide H (1), which showed modest antibacterial activity and toxicity to mammalian cells at micromolar concentrations. HRMS/MS, NMR, and advanced Marfey's analysis were used to assign the structure of 1 as a peptaibol containing 4-[(E)-2-butenyl]-4-methyl-l-threonine (Bmt), a hallmark structural motif of the cyclosporins. LC-MS detection of homologous tolypocladamide metabolites and phylogenomic analyses of peptaibol biosynthetic genes in other cultured Tolypocladium species allowed assignment of a putative tolypocladamide nonribosomal peptide synthetase gene.

Subcellular localization of fungal specialized metabolites

Fungal specialized metabolites play an important role in the environment and have impacted human health and survival significantly. These specialized metabolites are often the end product of a series of sequential and collaborating biosynthetic enzymes that reside within different subcellular compartments. A wide variety of methods have been developed to understand fungal specialized metabolite biosynthesis in terms of the chemical conversions and the biosynthetic enzymes required, however there are far fewer studies elucidating the compartmentalization of the same enzymes. This review illustrates the biosynthesis of specialized metabolites where the localization of all, or some, of the biosynthetic enzymes have been determined and describes the methods used to identify the sub-cellular localization.

Extracellular DNA Traps: Origin, Function and Implications for Anti-Cancer Therapies

Extracellular DNA may serve as marker in liquid biopsies to determine individual diagnosis and prognosis in cancer patients. Cell death or active release from various cell types, including immune cells can result in the release of DNA into the extracellular milieu. Neutrophils are important components of the innate immune system, controlling pathogens through phagocytosis and/or the release of neutrophil extracellular traps (NETs). NETs also promote tumor progression and metastasis, by modulating angiogenesis, anti-tumor immunity, blood clotting and inflammation and providing a supportive niche for metastasizing cancer cells. Besides neutrophils, other immune cells such as eosinophils, dendritic cells, monocytes/macrophages, mast cells, basophils and lymphocytes can also form extracellular traps (ETs) during cancer progression, indicating possible multiple origins of extracellular DNA in cancer. In this review, we summarize the pathomechanisms of ET formation generated by different cell types, and analyze these processes in the context of cancer. We also critically discuss potential ET-inhibiting agents, which may open new therapeutic strategies for cancer prevention and treatment.

Cyclosporin A up-regulated thromboxane A2 receptor through activation of MAPK and NF-κB pathways in rat mesenteric artery

Cyclosporin A (CsA) is an immunosuppressant used in transplantation patients and inflammatory diseases. CsA-induced local vasoconstriction can lead to serious side effects including nephrotoxicity and hypertension. However, the underlying mechanisms are not fully understood. Mesenteric artery rings of rats were cultured with CsA and specific inhibitors for mitogen-activating protein kinases (MAPK) and nuclear factor-κB (NF-κB) signaling pathways. A sensitive myograph recorded thromboxane (TP) receptor-mediated vasoconstriction. Protein levels of key signaling molecules were assessed by Western blotting. The results show that CsA up-regulated the TP receptor expression with the enhanced vasoconstriction in a dose- and time-dependent manner. Furthermore, the blockage of MAPKs or NF-κB activation markedly attenuated CsA-enhanced vasoconstriction and the TP receptor protein expression. Rats subcutaneously injected with CsA for three weeks showed increased blood pressure in vivo and increased contractile responses to a TP agonist ex vivo. CsA also enhanced TP receptor, as well as p-ERK1/2, p-p38, p- IκBα, p-NF-κB P65 protein levels and decreased IκBα protein expression, demonstrating that CsA induced TP receptor enhanced-vasoconstriction via activation of MAPK and NF-κB pathways. In conclusion, CsA up-regulated the expression of TP receptors via activation of MAPK and NF-κB pathways. The results may provide novel options for prevention of CsA-associated hypertension.

Discovery of immunosuppressive Lupane-type Triterpenoids from Hypericum longistylum

The phytochemistry study of Hypericum longistylum afforded one new degraded lupane-type triterpenoid, triterhyper A (1), and seven known congeners (2-8). The structures of those natural products were identified by extensive spectroscopic techniques and single crystal diffraction tests. Notably, triterhyper A (1) possessing an unusual 28-nor-lupane skeleton. More significantly, compounds 1-3 exhibited potential inhibitory effects on murine splenocytes proliferation stimulated by anti-CD3/anti-CD28 monoclonal antibodies (mAbs) and lipopolysaccharide (LPS), with IC₅₀ values ranging from (4.56 ± 0.45) μM to (18.34 ± 2.34) μM, highlighting that those isolates as potential lead compounds in the development of immunosuppressive drugs for autoimmune disease treatment.

A new nanosuspension prepared with wet milling method for oral delivery of highly variable drug Cyclosporine A: Development, optimization and in vivo evaluation

Cyclosporine A (CsA) is a cyclic polypeptide, that has been widely used for immunosuppression. This study aims to develop nanosuspension for oral administration of CsA using the wet milling (WM) method one of the top-down technologies. The WM method was optimized by studying the effects of critical process parameters for WM on the particle size (PS), particle size distribution (PDI), and zeta potential (ZP) of nanosuspensions using the Design of Experiment (DoE) approach. Nanosuspension was developed using hydroxypropyl methylcellulose (HPMC) and sodium dodecyl sulfate (SDS) and in vitro characterization studies were performed. In vitro dissolution and in vivo pharmacokinetic studies were conducted with biorelevant media (fasted and fed state simulated fluids) and fasted and fed states in rats, respectively. In vivo immunological studies were also performed. PS, PDI, and ZP values for nanosuspension were approximately 600 nm, 0.4, -25 mV, respectively. The solubility of CsA was increased by 4.5-folds by nanosuspensions. Dissolution studies showed that nanosuspension had higher dissolution than the commercial product in the FeSSIF medium. The pharmacokinetic study indicated that AUC_0-24 values of CsA nanosuspension were to be 2.09 and 5.51-fold higher than coarse powder in fasted and fed conditions, respectively. Immunological studies were carried out after oral administration of nanosuspension for 21 days, the ratio of CD4+/CD8+ was found to be more acceptable than the commercial product. These results demonstrated that nanosuspension is a promising approach for increasing the bioavailability and avoiding the food effect on absorption of CsA which one of the highly variable drugs.

Advances in solid-state fermentation for bioconversion of agricultural wastes to value-added products: Opportunities and challenges

The increase in solid waste has become a common problem and causes environmental pollution worldwide. A green approach to valorise solid waste for sustainable development is required. Agricultural residues are considered suitable for conversion into profitable products through solid-state fermentation (SSF). Agricultural wastes have high organic content that is used as potential substrates to produce value-added products through SSF. The importance of process variables used in solid-phase fermentation is described. The applications of SSF developed products in the food industry as flavouring agents, acidifiers, preservatives and flavour enhancers. SSF produces secondary metabolites and essential enzymes. Wastes from agricultural residues are used as bioremediation agents, biofuels and biocontrol agents through microbial processing. In this review paper, the value addition of agricultural wastes by SSF through green processing is discussed with the current knowledge on the scenarios, sustainability opportunities and future directions of a circular economy for solid waste utilisation.

Development of cyclosporine A nanosuspension: cytotoxicity and permeability on Caco-2 cell lines

Cyclosporine A is a calcineurin inhibitor and is usually used as an immunosuppressant medication. The main purpose of this study is to develop nanosuspension of polypeptide cyclosporine A by using the wet milling method for oral administration. Cell culture studies were also performed with human intestinal Caco-2 cell lines. Hydroxypropyl methylcellulose and sodium dodecyl sulfate were used as stabilizers in nanosuspension. In vitro characterization studies such as Fourier-transform infrared analysis and morphological imaging with scanning electron microscopy have been carried out with obtained cyclosporine A nanosuspension. The particle size, particle size distribution, and zeta potential values of the nanosuspension were measured approximately 400 nm, 0.4, and -25 mV, respectively. The solubility of cyclosporine A was increased 4.5 times in nanosuspension compared to the coarse cyclosporine A powder. As a result of cytotoxicity studies conducted with different concentrations, it was decided to conduct permeability studies at a dose equivalent to 150 µg/mL cyclosporine A. Permeation studies have shown that the nanosuspension increases cyclosporine A transport by 5 and 1.5 times, respectively, compared to coarse powder and commercial product.

Analysis of Molecular Interactions between Components in Phospholipid-Immunosuppressant-Antioxidant Mixed Langmuir Films

The study of Langmuir monolayers incorporating biomimetic and bioactive substances plays an important role today in assessing the properties and quality of the molecular films for potential biomedical applications. Here, miscibility of binary and ternary monolayers of phospholipid (dioleoyl phosphatidylcholine, DOPC), immunosuppressant (cyclosporine A, CsA), and antioxidant (lauryl gallate, LG) of varying molar fractions was analyzed by means of the Langmuir technique coupled with a surface potential (ΔV) module at the air-water interface. The surface pressure-area per molecule (π-A) isotherms provided information on the physical state of the films at a given surface pressure, the monolayer packing and ordering, and the type and strength of intermolecular interactions. Surface potential-area (ΔV-A) isotherms revealed the molecular orientation changes at the interface upon compression. In addition, the apparent dipole moment of the monolayer-forming molecules was determined from the surface potential isotherms. The obtained results indicated that the film compression provoked subsequent changes of CsA conformation and/or orientation, conferring better affinity for the hydrocarbon environment. The mutual interactions between the components were analyzed here in terms of the excess and total Gibbs energy of mixing, whose values depended on the stoichiometry of the mixed films. The strongest attraction, thus the highest thermodynamic stability, was found for a DOPC-CsA-LG mixture with a 1:1:2 molar ratio. Based on these results, a molecular model for the organization of the molecules within the Langmuir film was proposed. Through this model, we elucidated the significant role of LG in improving the miscibility of CsA in the model DOPC membrane and thus in increasing the stability of self-assembled monolayers by noncovalent interactions, such as H-bonds and Lifshitz-van der Waals forces. The above 1:1:2 combination of three components is revealed as the most promising film composition for the modification of implant device surfaces to improve their biocompatibility. Further insight into mechanisms concerning drug-membrane interactions at the molecular level is provided, which results in great importance for biocoating design and development as well as for drug release at target sites.

Cyclophilin A Plays Potential Roles in a Rat Model of Asthma and Suppression of Immune Response

Purpose

Cyclophilin A (CypA) inhibits CD4⁺ T cell signal transduction via interleukin-2-inducible T-cell kinase (Itk), a tyrosine kinase required for T helper (Th) 2 cells function. Furthermore, mice with CypA silencing developed allergic diseases associated with increased Th2 cytokines production. CD4⁺ T cells with a Th2-cytokine pattern have been demonstrated to have a pivotal role in the pathogenesis of asthma. However, the effects of CypA in regulating immunity in asthma and in relieving asthmatic symptoms in vivo are entirely unknown.

Methods

Recombinant CypA protein (rCypA) was generated and purified. Ovalbumin (OVA)-challenged asthmatic rats model and acetylcholine chloride (ACh)-induced contraction of tracheal spirals were established. The pulmonary resistance (RL) value of asthmatic rats in vivo and the isometric tension of tracheal spirals ex vivo were recorded by MFLab 3.01 software. The levels of Th1 and Th2 cytokines and the quantities of immunoglobulin (IgA, IgG, IgM and IgE) in the supernatants of rat spleen lymphocytes were detected and analysed by bio-plex Suspension Array System and ELISA, respectively. CD4⁺ T cells were separated by MicroBeads, and the levels of interleukin (IL)-4 and interferon-γ (IFN-γ) were detected by ELISA.

Results

rCypA (10 ng/kg) significantly reduced RL within 2–7 min in OVA-challenged asthmatic rats in vivo, and there were no significant differences compared with terbutaline (TB) and hydrocortisone (HC). Furthermore, rCypA (10 ng/mL) significantly reduced the isometric tension in the ACh-induced contraction of the tracheal spiral ex vivo, and the effect of rCypA was better than that of TB. Additionally, rCypA suppressed the secretion of both Th1 and Th2 cytokines, and the suppressive effects of rCypA were stronger than those of HC, especially on Th2 cytokines.

Conclusion

These findings indicate that CypA may serve as a potential novel therapeutic strategy for asthma.

Identification of isocyclosporins by collision-induced dissociation of doubly protonated species

Nonribosomal cyclopeptide cyclosporin A (CsA), produced by fungus Tolypocladium inflatum, is an extremely important immunosuppressive drug used in organ transplantations and for therapy of autoimmune diseases. Here we report for the first time production of CsA, along with related cyclosporins B and C, by Tolypocladium inflatum strains of marine origin (White Sea). Cyclosporins A-C contain an unusual amino acid, (4R)-4-((E)-2-butenyl)-4,N-dimethyl-l-threonine (MeBmt), and are prone to isomerization to non-active isocyclosporin by N→O acyl shift of valine connected to MeBmt in acidic conditions. CsA and isoCsA are not distinguishable in MS analysis of [M+H]⁺ ions due to rapid [CsA + H]⁺→[isoCsA + H]⁺ conversion. We found that the N→O acyl shift is completely suppressed in cyclosporine [M+2H]²⁺ ions, and their collision-induced dissociation (CID) can be used for rapid and unambiguous analysis of cyclosporins and isocylosporins. Fragmentation patterns of [CsA+2H]²⁺ and [isoCsA+2H]²⁺ ions were analyzed and explained. The developed approach could be useful for MS analysis of other peptides containing β-hydroxy-α-amino acids.

Unveiling the Interaction Potential Surface between Drug-Entrapped Polymeric Micelles Clarifying the High Drug Nanocarrier Efficiency

Polymeric micelles are invaluable media as drug nanocarriers. Although knowledge of an interaction between the micelles is a key to understanding the mechanisms and developing the superior functions, the interaction potential surface between drug-incorporated polymeric micelles has not yet been quantitatively evaluated due to the extremely complex structure. Here, the interaction potential surface between drug-entrapped polymeric micelles was unveiled by combining a small-angle scattering experiment and a model-potential-free liquid-state theory. Triblock copolymer composed of poly(ethylene oxide) and poly(propylene oxide) was investigated over a wide concentration range (0.5-10.0 wt %). Effects of the entrapment of a water-insoluble hydrophobic drug, cyclosporin A, on the interaction were explored by comparing the interactions with and without the drug. The results directly clarified the high drug carrier efficiency in terms of the interaction between the micelles. In addition, an investigation based on density functional theory provided a deeper insight into the monomer contribution to the extremely stable dispersion of the nanocarrier.

Cytochrome P450 enzymes in fungal natural product biosynthesis

Covering: 2015 to the end of 2020 Fungal-derived polyketides, non-ribosomal peptides, terpenoids and their hybrids contribute significantly to the chemical space of total natural products. Cytochrome P450 enzymes play essential roles in fungal natural product biosynthesis with their broad substrate scope, great catalytic versatility and high frequency of involvement. Due to the membrane-bound nature, the functional and mechanistic understandings for fungal P450s have been limited for quite a long time. However, recent technical advances, such as the efficient and precise genome editing techniques and the development of several filamentous fungal strains as heterologous P450 expression hosts, have led to remarkable achievements in fungal P450 studies. Here, we provide a comprehensive review to cover the most recent progresses from 2015 to 2020 on catalytic functions and mechanisms, research methodologies and remaining challenges in the fast-growing field of fungal natural product biosynthetic P450s.

Cordycepin, a metabolite of Cordyceps militaris, reduces immune-related gene expression in insects

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High doses of cordycepin are lethal to G. mellonella.

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Cordycepin interacts with EPF to increase the rate of G. mellonella mortality.

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Cordycepin reduces immune-related gene expression in G. mellonella and S2r+ cells.

Hypocrealean entomopathogenic fungi (EPF) (Sordariomycetes, Ascomycota) are natural regulators of insect populations in terrestrial environments. Their obligately-killing life-cycle means that there is likely to be strong selection pressure for traits that allow them to evade the effects of the host immune system. In this study, we quantified the effects of cordycepin (3′-deoxyadenosine), a secondary metabolite produced by Cordyceps militaris (Hypocreales, Cordycipitaceae), on insect susceptibility to EPF infection and on insect immune gene expression. Application of the immune stimulant curdlan (20 µg ml⁻¹, linear beta-1,3-glucan, a constituent of fungal cell walls) to Drosophila melanogaster S2r+ cells resulted in a significant increase in the expression of the immune effector gene metchnikowin compared to a DMSO-only control, but there was no significant increase when curdlan was co-applied with 25 µg ml⁻¹ cordycepin dissolved in DMSO. Injection of cordycepin into larvae of Galleria mellonella (Lepidoptera: Pyralidae) resulted in dose-dependent mortality (LC₅₀ of cordycepin = 2.1 mg per insect 6 days after treatment). Incubating conidia of C. militaris and Beauveria bassiana (Hypocreales, Cordycipitaceae; an EPF that does not synthesize cordycepin) with 3.0 mg ml⁻¹ cordycepin had no effect on the numbers of conidia germinating in vitro. Co-injection of G. mellonella with a low concentration of cordycepin (3.0 mg ml⁻¹) plus 10 or 100 conidia per insect of C. militaris or B. bassiana caused a significant decrease in insect median survival time compared to injection with the EPF on their own. Analysis of predicted vs. observed mortalities indicated a synergistic interaction between cordycepin and the EPF. The injection of C. militaris and B. bassiana into G. mellonella resulted in increased expression of the insect immune effector genes lysozyme, IMPI and gallerimycin at 72 h post injection, but this did not occur when the EPF were co-injected with 3.0 mg ml⁻¹ cordycepin. In addition, we observed increased expression of IMPI and lysozyme at 48 h after injection with C. militaris, B. bassiana and sham injection (indicating a wounding response), but this was also prevented by application of cordycepin. These results suggest that cordycepin has potential to act as a suppressor of the immune response during fungal infection of insect hosts.

Production of Diverse Beauveriolide Analogs in Closely Related Fungi: a Rare Case of Fungal Chemodiversity

Fungal chemodiversity is well known in part due to the production of diverse analogous compounds by a single biosynthetic gene cluster (BGC). Usually, similar or the same metabolites are produced by closely related fungal species under a given condition, the foundation of fungal chemotaxonomy. Here, we report a rare case of the production of the cyclodepsipeptide beauveriolides (BVDs) in three insect-pathogenic fungi. We found that the more closely related fungi Beauveria bassiana and Beauveria brongniartii produced structurally distinct analogs of BVDs, whereas the less-close relatives B. brongniartii and Cordyceps militaris biosynthesized structurally similar congeners under the same growth condition. It was verified that a conserved BGC containing four genes is responsible for BVD biosynthesis in three fungi, including a polyketide synthase (PKS) for the production of 3-hydroxy fatty acids (FAs) with chain length variations. In contrast to BVD production patterns, phylogenetic analysis of the BGC enzymes or enzyme domains largely resulted in the congruence relationship with fungal speciation. Feeding assays demonstrated that an FA with a chain length of eight carbon atoms was preferentially utilized, whereas an FA with a chain longer than 10 carbon atoms could not be used as a substrate for BVD biosynthesis. Insect survival assays suggested that the contribution of BVDs to fungal virulence might be associated with the susceptibility of insect species. The results of this study enrich the knowledge of fungal secondary metabolic diversity that can question the reliability of fungal chemotaxonomy.IMPORTANCE Fungal chemotaxonomy is an approach to classify fungi based on the fungal production profile of metabolites, especially the secondary metabolites. We found an atypical example that could question the reliability of fungal chemical classifications in this study, i.e., the more closely related entomopathogenic species Beauveria bassiana and Beauveria brongniartii produced structurally different congeners of the cyclodepsipeptide beauveriolides, whereas the rather divergent species B. brongniartii and Cordyceps militaris biosynthesized similar analogs under the same growth condition. The conserved biosynthetic gene cluster (BGC) containing four genes present in each species is responsible for beauveriolide production. In contrast to the compound formation profiles, the phylogenies of biosynthetic enzymes or enzymatic domains show associations with fungal speciation. Dependent on the insect species, production of beauveriolides may contribute to fungal virulence against the susceptible insect hosts. The findings in this study augment the diversity of fungal secondary metabolisms.

Impact of non-proteinogenic amino acids in the discovery and development of peptide therapeutics

With the development of modern chemistry and biology, non-proteinogenic amino acids (NPAAs) have become a powerful tool for developing peptide-based drug candidates. Drug-like properties of peptidic medicines, due to the smaller size and simpler structure compared to large proteins, can be changed fundamentally by introducing NPAAs in its sequence. While peptides composed of natural amino acids can be used as drug candidates, the majority have shown to be less stable in biological conditions. The impact of NPAA incorporation can be extremely beneficial in improving the stability, potency, permeability, and bioavailability of peptide-based therapies. Conversely, undesired effects such as toxicity or immunogenicity should also be considered. The impact of NPAAs in the development of peptide-based therapeutics is reviewed in this article. Further, numerous examples of peptides containing NPAAs are presented to highlight the ongoing development in peptide-based therapeutics.

Immunosuppressive Nor-isopimarane Diterpenes from Cultures of the Fungicolous Fungus Xylaria longipes HFG1018

Eighteen new nor-isopimarane diterpenes, xylarinorditerpenes A-R (1-18), along with two previously reported compounds, 14α,16-epoxy-18-norisopimar-7-en-4α-ol (19) and the labdane-type diterpene agatadiol (20), were isolated from cultures of the fungicolous fungus Xylaria longipes HFG1018 isolated from the wood-rotting basidiomycete Fomitopsis betulinus. The structure elucidation and relative configuration assignments of 1-18 were accomplished by interpretation of spectroscopic data and through computational methods. The absolute configurations of 1, 4, and 16 were determined by single-crystal X-ray diffraction. Compounds 1-16 possess an 18- or 19-nor-isopimarane skeleton, and compounds 17 and 18 possess an 18,19-dinor-isopimarane skeleton. Compounds 2-5, 9, 14, 19, and 20 showed immunosuppressive activity but were devoid of cytotoxicity against the cell proliferation by concanavalin A-induced T lymphocytes and lipopolysaccharide-induced B lymphocytes, with IC₅₀ values varying from 1.0 to 27.2 μM and from 16.1 to 51.8 μM, respectively.

Non-lipopeptide fungi-derived peptide antibiotics developed since 2000

The 2,5-diketopiperazines (DKPs) are the smallest cyclopeptides and their basic structure includes a six-membered piperazine nucleus. Typical peptides lack a special functional group in the oligopeptide nucleus. Both are produced by at least 35 representative genera of fungi, and possess huge potential as pharmaceutical drugs and biocontrol agents. To date, only cyclosporin A has been developed into a commercial product. This review summarises 186 fungi-derived compounds reported since 2000. Antibiotic (antibacterial, antifungal, synergistic antifungal, antiviral, antimycobacterial, antimalarial, antileishmanial, insecticidal, antitrypanosomal, nematicidal and antimicroalgal) activities are discussed for 107 of them, including 66 DKPs (14 epipolythiodioxopiperazines, 20 polysulphide bridge-free thiodiketopiperazines, and 32 sulphur-free prenylated indole DKPs), 15 highly N-methylated, and 26 non-highly N-methylated typical peptides. Structure-activity relationships, mechanisms of action, and research methods are covered in detail. Additionally, biosynthases of tardioxopiperazines and neoechinulins are highlighted. These compounds have attracted considerable interest within the pharmaceutical and agrochemical industries.

(±)-Alternamgin, a Pair of Enantiomeric Polyketides, from the Endophytic Fungi Alternaria sp. MG1

A pair of enantiomeric polyketides, (+)- and (-)-alternamgin (1), featuring an unprecedented 6/6/6/6/5/6/6 seven ring backbone, were isolated from the endophytic fungi Alternaria sp. MG1. The relative configuration of 1 was determined using X-ray diffraction, and the absolute configurations of (±)-1 were confirmed by comparing the experimental and calculated ECD data. Plausible biosynthetic pathways for 1 were proposed. Compound (-)-1 exhibited moderate necrosis rates to Hela and HepG2 cells, but (+)-1 only showed similar necrosis rates to HepG2 cells.

Drug Bioavailability Enhancing Agents of Natural Origin (Bioenhancers) that Modulate Drug Membrane Permeation and Pre-Systemic Metabolism

Many new chemical entities are discovered with high therapeutic potential, however, many of these compounds exhibit unfavorable pharmacokinetic properties due to poor solubility and/or poor membrane permeation characteristics. The latter is mainly due to the lipid-like barrier imposed by epithelial mucosal layers, which have to be crossed by drug molecules in order to exert a therapeutic effect. Another barrier is the pre-systemic metabolic degradation of drug molecules, mainly by cytochrome P450 enzymes located in the intestinal enterocytes and liver hepatocytes. Although the nasal, buccal and pulmonary routes of administration avoid the first-pass effect, they are still dependent on absorption of drug molecules across the mucosal surfaces to achieve systemic drug delivery. Bioenhancers (drug absorption enhancers of natural origin) have been identified that can increase the quantity of unchanged drug that appears in the systemic blood circulation by means of modulating membrane permeation and/or pre-systemic metabolism. The aim of this paper is to provide an overview of natural bioenhancers and their main mechanisms of action for the nasal, buccal, pulmonary and oral routes of drug administration. Poorly bioavailable drugs such as large, hydrophilic therapeutics are often administered by injections. Bioenhancers may potentially be used to benefit patients by making systemic delivery of these poorly bioavailable drugs possible via alternative routes of administration (i.e., oral, nasal, buccal or pulmonary routes of administration) and may also reduce dosages of small molecular drugs and thereby reduce treatment costs.

Cyclic undecapeptide Cyclosporin A mediated inhibition of amyloid synthesis: Implications in alleviation of amyloid induced neurotoxicity

Amyloids are highly organized fibril aggregates arise from inappropriately folded form of the protein or polypeptide precursors under both physiological as well as simulated ambience. Amyloid synthesis is a multistep process that involves formation of several metastable intermediates. Among various intermediate species, the as-formed soluble oligomers are extremely toxic to the neuronal cells. In the present study, we evaluated cyclosporine A (CsA), an undecapeptide, for its potential to prevent aggregation of model protein ovalbumin (OVA). In an attempt to elucidate involved operative mechanism, the preliminary studies delineate that CsA affects both primary nucleation as well as other secondary pathways involved in OVA fibrillation process. By its specific interaction with amyloid intermediates, the cyclic peptide CsA seems to regulate the lag phase of the fibrillation process in concentration dependent manner. The present study further suggests that exposure to CsA during lag phase ensues in reversal of OVA fibrillation process. On the contrary, mature OVA fibril remained impervious to the CsA treatment. The cyclic undecapeptide CsA was also found to successfully alleviate amyloid induced toxicity in neuroblastoma cells.