Phellinins A1 and A2, new styrylpyrones from the culture broth of Phellinus sp. KACC93057P: I. Fermentation, taxonomy, isolation and biological properties

Evaluating the Biocontrol Efficacy and Antioxidant Potential of Phellinus caribaeo-quercicola-A First Report Dual-Action Endophyte From Inula racemosa Hook. F

Phellinus caribaeo-quercicola is a basidiomycetous fungus, isolated as an endophyte in this study from the healthy and symptomless leaves of Inula racemosa Hook. f., an important medicinal herb growing in Kashmir Himalaya. This study combines morphological, molecular and phylogenetic techniques to identify the fungal endophyte, using the ITS sequence of nrDNA. A detached leaf assay was conducted to assess the pathogenicity of the fungal endophyte suggesting its mutually symbiotic relationship with the host. The authors also investigated the antifungal potential of the isolated endophytic strain to ascertain its use as a biocontrol agent. The study shows that P. caribaeo-quercicola INL3-2 strain exhibits biocontrol activity against four key fungal phytopathogens that cause significant agronomic and economic losses: Aspergillus flavus, Aspergillus niger, Fusarium solani, and Fusarium oxysporum. Notably, P. caribaeo-quercicola INL3-2 strain is highly effective against A. flavus, with an inhibition percentage of 57.63%. In addition, this study investigates the antioxidant activity of P. caribaeo-quercicola INL3-2 strain crude extracts using ethyl acetate and methanol as solvents. The results showed that the methanolic fraction of P. caribaeo-quercicola exhibits potential as an antioxidant agent, with an IC50 value of 171.90 ± 1.15 µg/mL. This investigation is first of its kind and marks the initial report of this fungal basidiomycete, P. caribaeo-quercicola, as an endophyte associated with a medicinal plant. The findings of this study highlight the potential of P. caribaeo-quercicola INL3-2 strain as a dual-action agent with both biocontrol and antioxidant properties consistent with the medicinal properties of Inula racemosa. This endophytic fungus could be a promising source of natural compounds for use in agriculture, medicine, and beyond.

Development of RP HPLC-PDA method for simultaneous quantitative analysis of Inoscavin A and Meshimakobnol A and application on some Phellinus mushroom species

Phellinus igniarius, a medicinal mushroom containing many active ingredients with health benefits, can be applied in functional food. At present, the quantification of the main active ingredients from higher fungi (Ganoderma, Phellinus…) materials from different growing sources is a mandatory requirement to standardize the input resources of pharmaceutical and food production. Our study's aims are to perfect the RP HPLC-PDA method for quantitative analysis of Inoscavin A and Meshimakobnol A which are two main active ingredients present in Phellinus mushroom. In this analytical method, a C18-HPLC column and the mixture of methanol and formic acid solutions (pH = 2.2) are used to analyze and elute the active substances with the column activity parameters being the concentration gradient. This perfect method was tested for system suitability, repeatability, intermediate precision, recovery, and linear curve calibration to validate the method. After validation, the perfected RP HPLC-PDA method was applied to analyze eight samples of Phellinus and three samples of Ganoderma mushroom category. This method can be the basis for classifying between Phellinus and some other medicinal mushrooms.

Phaeolschidin F, a new symmetrical bis(styrylpyrone) derivative with redox-catalyzing activity from the mushroom Gymnopilus aeruginosus (order Agaricales)

Phaeolschidin F (1) was isolated from fruiting bodies of the bitter and toxic mushroom Gymnopilus aeruginosus. Structure analysis by NMR and MS revealed that 1 is a new symmetrical bis(styrylpyrone). A series of anti-oxidant and pro-oxidant tests characterized that 1 is a redox catalyst having more anti-oxidant and less pro-oxidant activities than quercetin.

Styrylpyrone Derivative (SPD) Extracted from Goniothalamus umbrosus Binds to Dengue Virus Serotype-2 Envelope Protein and Inhibits Early Stage of Virus Replication

A study was conducted to investigate the anti-viral effect of a styrylpyrone derivative (SPD) called goniothalamin and the effects on the dengue virus serotype 2 (DENV-2) replication cycle. The SPD was prepared from the root of Goniothalamus umbrosus after purification with petroleum ether. The isolated SPD was then subjected to gas chromatography–mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses for structure validation. The cytotoxicity of the SPD was evaluated using a cell viability assay, while the anti-viral activity of the SPD towards DENV-2 was confirmed by conducting a foci reduction assay which involved virus yield reduction, time-of-addition, and time removal assays. Transcriptomic analysis via quantitative real-time polymerase chain reaction (qRT-PCR) using the DENV-2 E gene was conducted to investigate the level of gene transcript. Immunocytochemistry analysis was used to investigate the effects of SPD treatment on protein E expression. Finally, software molecular docking of the SPD and E protein was also performed. The cytotoxicity assay confirmed that the SPD was not toxic to Vero cells, even at the highest concentration tested. In the time-of-addition assay, more than 80% foci reduction was observed when SPDs were administered at 2 h post-infection (hpi), and the reduction percentage then dropped with the delay of the treatment time, suggesting the inhibition of the early replication cycle. However, the time removal assay showed that more than 80% reduction could only be observed after 96 h post-treatment with the SPD. Treatment with the SPD reduced the progeny infectivity when treated for 24 h and was dose-dependent. The result showed that transcript level of the E gene in infected cells treated with the SPD was reduced compared to infected cells without treatment. In immunocytochemistry analysis, the DENV-2 E protein exhibited similar expression trends, shown by the gene transcription level. Molecular docking showed that the SPD can interact with E protein through hydrogen bonds and other interactions. Overall, this study showed that SPDs have the potential to be anti-DENV-2 via a reduction in viral progeny infectivity and a reduction in the expression of the DENV-2 E gene and protein at different phases of viral replication. SPDs should be further researched to be developed into an effective anti-viral treatment, particularly for early-phase dengue viral infection.

The phytochemistry and pharmacology of medicinal fungi of the genus Phellinus: a review

Phellinus Quél is one of the largest genera of Hymenochaetaceae, which is comprised of about 220 species. Most Phellinus macro-fungi are perennial lignicolous mushrooms, which are widely distributed on Earth. Some Phellinus fungi are historically recorded as traditional medicines used to treat various diseases in eastern Asian countries, especially China, Japan and Korean. Previous phytochemical studies have revealed that Phellinus fungi produce diverse secondary metabolites, which mainly contain polysaccharides, flavones, coumarins, terpenes, steroids, and styrylpyranones. Pharmacological documents have demonstrated that Phellinus mushrooms and their compounds have a variety of bioactivities, such as anti-tumor, immunomodulation, anti-oxidative and anti-inflammation, anti-diabetes, neuro-protection, and anti-viral effects. This review surveys the literature reporting the isolation, characterization, and bioactivities of secondary metabolites from the fungi of the genus Phellinus, focusing on studies published in the literature up to April 2020. Herein, a total of more than 300 compounds from 13 Phellinus species and their isolation, characterization, chemistry, pharmacological activities, and relevant molecular mechanisms are comprehensively summarized.

Gold Catalysis for Heterocyclic Chemistry: A Representative Case Study on Pyrone Natural Products

2-Pyrones and 4-pyrones are common structural motifs in bioactive natural products. However, traditional methods for their synthesis, which try to emulate the biosynthetic pathway of cyclization of a 1,3,5-tricarbonyl precursor, are often harsh and, therefore, not particularly suitable for applications to polyfunctionalized and/or sensitive target compounds. π-Acid catalysis, in contrast, has proved to be better for a systematic exploration of the pyrone estate. To this end, alkynes are used as stable ketone surrogates, which can be activated under exceedingly mild conditions due to the pronounced carbophilicity of [LAu]⁺ fragments (L=two electron donor ligand); attack of a tethered ester carbonyl group onto the transient alkyne-gold complex then forges the pyrone ring in a fully regiocontrolled manner.

Chain terpenoids isolated from cultures of basidiomycete Phellinus sp

Two new sesquiterpenoids (phellinuins H and I), together with five known compounds, were isolated from cultures of mushroom Phellinus sp. Their structures were elucidated based on comparison of nuclear magnetic resonance and MS data and those reported in the literature. All of these compounds were tested for cytotoxicity against five cancer cell lines (HL-60, SMMC-721, A-549, MCF-7, and SW-480).

Fungal natural products in research and development

To date approximately 100 000 fungal species are known although far more than one million are expected. The variety of species and the diversity of their habitats, some of them less exploited, allow the conclusion that fungi continue to be a rich source of new metabolites. Besides the conventional fungal isolates, an increasing interest in endophytic and in marine-derived fungi has been noticed. In addition new screening strategies based on innovative chemical, biological, and genetic approaches have led to novel fungal metabolites in recent years. The present review focuses on new fungal natural products published from 2009 to 2013 highlighting the originality of the structures and their biological potential. Furthermore synthetic products based on fungal metabolites as well as new developments in the uses or the biological activity of known compounds or new derivatives are discussed.

Safety assessment of the fermented Phylloporia ribis (Lonicera japonica Thunb.) mycelia by oral acute toxicity study in mice and 90-day feeding study in rats

Phylloporia ribis is an edible fungus in China. Its fermented mycelia have been approved by the National Health and Family Planning Commission (NHFPC) of PR China for use as a novel food material, but little information on its safety is available. The present research was the first to evaluate acute and subchronic toxicity in experimental animals of fermented Phylloporia ribis mycelia (FPM) following standard procedures. In acute toxicity study, FPM was orally administered to male and female mice twice a day at single dose of 10 g/kg bw. The Maximum Tolerated Dose (MTD) of FPM for mice of both sexes was over 10 g/kg bw. No death and abnormal behaviors occurred during 14 days study except for an increased locomotor activity in three animals. In 90-day feeding study, male and female Sprague-Dawley rats were fed diets containing 10.0%, 5.0%, 2.5%, 1.25% and 0% (control) FPM for 90 days. The treatment caused no effects on mortality, gross pathology, histology, hematology, and blood chemistry, no dose-dependent changes in food consumption, but caused effect on body weight gain compared with control group. The No Observed Adverse-Effect Level (NOAEL) of FPM was greater than 8.7 g/kg bw/day in both sexes of rats.

Styrylpyrone-class compounds from medicinal fungi Phellinus and Inonotus spp., and their medicinal importance

Members of the genera Phellinus and Inonotus, including P. linteus, P. igniarius, P. ribis, I. obliquus and I. xeranticus are well-known medicinal fungi (mushrooms) and have been used in treatment of cancer, diabetes, bacterial and viral infections and ulcer. Adverse effects of these medicinal mushrooms have not yet been reported, indicating the safe nature of these mushrooms. Polysaccharides, particularly β-glucan, are considered the compounds responsible for the biological activity of medicinal mushrooms. However, there is only a limited amount of evidence to indicate that polysaccharides are in fact responsible for the biological effects of these medicinal mushrooms. Recently, many research groups have begun identification of active low-MW compounds in medicinal mushrooms, with a focus on the yellow polyphenol pigments, which are composed of a styrylpyrone class of compounds. Interestingly, a representative group of medicinal fungi, including P. linteus, P. igniarius, P. ribis, I. obliquus and I. xeranticus were shown to produce a large and diverse range of styrylpyrone-type polyphenol pigments that exhibited various biological activities, including anti-oxidative, anti-inflammatory, cytotoxic, anti-platelet aggregation, anti-diabetic, anti-dementia and anti-viral effects. Styrylpyrone pigments in mushrooms are thought to have a role similar to that of flavonoids in plants. The unique and unprecedented carbon skeleton of fused styrylpyrone might be an attractive molecular scaffold for pharmacological applications. In this review, the structural diversity, biological effects and biogenesis of styrylpyrone-class polyphenols from medicinal fungi are described.