Phenylisotertronic acids from the TCM endophytic fungus Phyllosticta sp

Endophytic Fungi: A Treasure Trove of Antifungal Metabolites

Emerging and reemerging fungal infections are very common in nosocomial and non-nosocomial settings in people having poor immunogenic profiles either due to hematopoietic stem cell transplants or are using immunomodulators to treat chronic inflammatory disease or autoimmune disorders, undergoing cancer therapy or suffering from an immune weakening disease like HIV. The refractory behavior of opportunistic fungi has necessitated the discovery of unconventional antifungals. The emergence of black fungus infection during COVID-19 also triggered the antifungal discovery program. Natural products are one of the alternative sources of antifungals. Endophytic fungi reside and co-evolve within their host plants and, therefore, offer a unique bioresource of novel chemical scaffolds with an array of bioactivities. Hence, immense possibilities exist that these unique chemical scaffolds expressed by the endophytic fungi may play a crucial role in overcoming the burgeoning antimicrobial resistance. These chemical scaffolds so expressed by these endophytic fungi comprise an array of chemical classes beginning from cyclic peptides, sesquiterpenoids, phenols, anthraquinones, coumarins, etc. In this study, endophytic fungi reported in the last six years (2018-2023) have been explored to document the antifungal entities they produce. Approximately 244 antifungal metabolites have been documented in this period by different groups of fungi existing as endophytes. Various aspects of these antifungal metabolites, such as antifungal potential and their chemical structures, have been presented. Yet another unique aspect of this review is the exploration of volatile antifungal compounds produced by these endophytic fungi. Further strategies like epigenetic modifications by chemical as well as biological methods and OSMAC to induce the silent gene clusters have also been presented to generate unprecedented bioactive compounds from these endophytic fungi.

Asymmetric interaction and concurrent remediation of copper and atrazine by Acorus tatarinowii in an aquatic system

To clarify the influence of organic pesticides on phytoremediation of potentially toxic metal elements, hydroponically-grown Acorus tatarinowii was used to repair copper pollution at six concentration levels with and without atrazine. Removal outcomes and processes exhibited asymmetry in an aquatic system. In plants, the addition of atrazine brought as much as 20.5% copper than control. Total amounts, percentage of protein or pectin combined copper and leaf: root ratio of copper were enhanced correspondingly. In solutions, cupric ions (Cu²⁺) were eliminated as much as 95.6% in plant remediation system. Though atrazine resulted in a quarter more absorption equilibrium concentration, the absorption reaction rate half declined. Copper removal in the system was contributed by both bound copper in solution and plant accumulation, and atrazine magnified contribution weight of the later one. Concurrent copper decreased absolute and relative amounts of atrazine in A. tatarinowii, indicating the influence of copper was mainly to reduce atrazine uptake by A. tatarinowii rather than to change the transformation of atrazine in plants. Copper exhibited antagonistic effects with atrazine in term of plant biomass, photosynthesis and oxidative-related responses (malondialdehyde, Ca, Fe and Mn), which might give support to asymmetry interaction between copper and atrazine accumulation in A. tatarinowii.

γ-Aromatic Butenolides of Microbial Source - A Review of Their Structures, Biological Activities and Biosynthesis

γ-Aromatic butenolides (γ-AB) are an important type of structures found in many bioactive microbial secondary metabolites (SMs). γ-AB refer to a group of natural products (NPs) containing five-membered (unsaturated) lactones with 3-phenyl and 4-benzyl substituents. Their wide-range biological activities have inspired pharmaceutical chemists to explore its biosynthesis mechanisms and design strategies to construct the γ-AB skeleton. Recently, there are a great deal of interesting research progress on the structures, biological activities and biosynthesis of γ-AB. This review will focus on these aspects and summarize the important achievements of γ-AB from 1975 to 2021.

Neuroprotective Activities of Constituents from Phyllosticta capitalensis, an Endophyte Fungus of Loropetalum chinense var. rubrum

One new dioxolanone derivative, guignardianone G (1) and twelve known compounds (2-13) were isolated from the 95 % ethanol extract of the plant endophytic fungus Phyllosticta capitalensis cultured in rice medium. Among these known compounds, isoaltenuene (3), brassicasterol (7), 5,6-epoxyergosterol (8), citreoanthrasteroid A (9), demethylincisterol A (10), and chaxine C (11) were reported from Phyllosticta sp. for the first time. The structure of 1 was elucidated by 1D- and 2D-NMR experiments and HR-ESI-MS data analysis, and its absolute configuration was established through the comprehensive use of the methods of modified Mosher methods, calculations of ECD spectra and optical rotation values. The neuroprotective activity of compounds (1-9, 11-13) were evaluated on PC12 cells damage induced by glutamate, and compounds 9 and 12 showed potential neuroprotective activities with half effective concentration (EC₅₀ ) of 24.2 and 33.9 μM, respectively.

Biological Activities of Some New Secondary Metabolites Isolated from Endophytic Fungi: A Review Study

Secondary metabolites isolated from plant endophytic fungi have been getting more and more attention. Some secondary metabolites exhibit high biological activities, hence, they have potential to be used for promising lead compounds in drug discovery. In this review, a total of 134 journal articles (from 2017 to 2019) were reviewed and the chemical structures of 449 new metabolites, including polyketides, terpenoids, steroids and so on, were summarized. Besides, various biological activities and structure-activity relationship of some compounds were aslo described.

New phthalide derivatives from the Biscogniauxia sp. and their activities

Five new phthalide derivatives, biscogniphthalides A-D (1, 2, 3a/3b, and 4), were isolated from Biscogniauxia sp. (No. 69-8-7-1), along with one related known phthalide (5). Their structures were determined by comprehensive spectroscopic analyses, chemical derivatization, and quantum chemical ECD calculations. In addition, the anti-acetyl cholinesterase, antimicrobial, and anti-α-glucosidase activities of 1-5 were evaluated.