Erinachromanes A and B and Erinaphenol A from the Culture Broth of Hericium erinaceus

The ethnopharmacology, phytochemistry and pharmacology of the genus Hericium

ETHNOPHARMACOLOGICAL RELEVANCE

Mushrooms in the genus Hericium are used as functional food and traditional medicines for a long history in East Asian countries such as China, India, Japan, and Korea. Some species of Hericium are called as monkey head mushroom (Houtougu) in China and Yamabushitake in Japan, which are traditionally considered as rare and precious health promoting food and medicinal materials for the treatment of dyspepsia, insomnia, chronic gastritis, and digestive tract tumors.

THE AIM OF THE REVIEW

This review aims to summarize the ethnopharmacology and structural diversity of secondary metabolites from Hericium species, as well as the pharmacological activities of the crude extracts and pure compounds from Hericium species in recent years.

MATERIALS AND METHODS

All the information was gathered by searching Scifinder, PubMed, Web of Science, ScienceDirect, Springer, Wiley, ACS, CNKI, Baidu Scholar, Google Scholar databases and other published materials (books and Ph.D. and M. Sc. Dissertations) using the keywords "Hericium", "Traditional uses", "Chemical composition", "Quality control" and "Pharmacological activity" (1971-May 2023). The species name was checked with https://www.mycobank.org/.

RESULTS

The traditional uses of Hericium species were summarized, and 230 secondary metabolites from Hericium species were summarized and classified into six classes, mainly focusing on their chemical diversity, biosynthesis, biological activities. The modern pharmacological experiments in vivo or in vitro on their crude and fractionated extracts showed that the chemical components from Hericium species have a broad range of bioactivities, including neuroprotective, antimicrobial, anticancer, α-glucosidase inhibitory, antioxidant, and anti-inflammatory activities.

CONCLUSIONS

The secondary metabolites discovered from Hericium species are highly structurally diverse, and they have the potential to be rich resources of bioactive fungal natural products. Moreover, the unveiled bioactivities of their crude extracts and pure compounds are closely related to critical human health concerns, and in-depth studies on the potential lead compounds, mechanism of pharmacological effects and pharmaceutical properties are clearly warranted.

Flask and reactor scale production of plant growth regulators by Inonotus hispidus: optimization, immobilization and kinetic parameters

The aims of the presented study are to compare submerged, static, and solid-state fermentation in the production of gibberellic acid (GA3), indole acetic acid (IAA), and abscisic acid (ABA) by Inonotus hispidus, to optimize with a statistical approach, and to determine the kinetic parameters under flask and reactor conditions. The maximum concentrations of GA3, (2478.85 ± 68.53 mg/L), ABA, (273.26 ± 6.17 mg/L) and IAA (30.67 ± 0.19 mg/L) were obtained in submerged conditions. After optimization, these values reached 2998.85 ± 28.85, 339.47 ± 5.50, and 34.56 ± 0.25 mg/L, respectively. Immobilization of fungal cells on synthetic fiber, polyurethane foam, and alginate beads resulted in an increase in plant growth regulators (PGR) production by 5.53%- 5.79% under optimized conditions. At the reactor scale, a significant increase was observed for GA3 concentration, 5441.54 mg/L, which was 2.14 and 1.45 times higher than non-optimized and optimized conditions in the flask scale, respectively. The maximum values for ABA and IAA were 390.39 and 44.79 mg/L, respectively. Although the specific growth rate (µ) decreases relatively from non-optimized flask conditions to optimized reactor conditions, it was observed that the PGR amounts produced per liter medium (rp) and per gram biomass (Qp) increased significantly. This is the first report on the synthesis of PGR by Inonotus hispidus which could be crucial for sustainable agriculture.

Optimization and reactor-scale production of plant growth regulators by Pleurotus eryngii

The aims of the this study are to select the best cultivation type for plant growth regulator (PGR) production, to optimize PGR production with statistical experimental design, and to calculate bioprocess parameters and yield factors during PGR production by P. eryngii in flask and reactor scales. Submerged fermentation was the best cultivation type with 4438.67 ± 37.14, 436.95 ± 27.31, and 54.32 ± 3.21 mg/L of GA3, ABA, and IAA production values, respectively. The Plackett-Burman and Box-Behnken designs were used to determine effective culture parameters and interactive effects of the selected culture parameters on PGR production by Pleurotus eryngii under submerged fermentation. The statistical model is valid for predicting PGR production by P. eryngii. After these studies, maximum PGR production (7926.17 ± 334.09, 634.92 ± 12.15, and 55.41 ± 4.38 mg/L for GA3, ABA, and IAA, respectively) was reached on the 18th day of fermentation under optimized conditions. The optimum formula was 50 g/L fructose, 3 g/L NaNO3, and 1.5 g/L KH2PO4, 1 mg/L thiamine, incubation temperature 25 °C, initial medium pH 7.0, and an agitation speed of 150 rpm. The kinetics of PGR production was investigated in batch cultivation under 3-L stirred tank reactor conditions. Concentrations of GA3, ABA, and IAA of 10,545.00 ± 527.25, 872.32 ± 21.81, and 60.48 ± 3.48 mg/L were obtained at the reactor scale which were 4.1, 3.4, and 2.3 times higher than the initial screening values. The specific growth rate (µ), the volumetric (rp) and specific (Qp) PGR production rates, 486.11 mg/L/day and 107.43 mg/g biomass/day for GA3, confirmed the successful transfer of optimized conditions to the reactor scale. In the presented study, PGR production of P. eryngii is reported for the first time.

Microbispofurans A-C, plant growth-promoting furancarboxylic acids from plant root-derived Microbispora sp

Microbispofurans A-C (1-3), new alkyl/alkenyl furancarboxylic acids, were isolated from the culture extract of the plant root-derived Microbispora sp. RD004716. The planar structures of 1-3 were determined by extensive analysis of 1D and 2D NMR spectroscopic data. Although 1-3 showed no appreciable antimicrobial activity or cytotoxicity, strong plant growth-promotion activity of the germinated red leaf lettuce seeds was observed at 10 μM. Furancarboxylic acids and their methyl esters were found in actinomycetes and fungi; however, the isolation of furandicarboxylic acid was unprecedented.

Bio-Derived Furanic Compounds with Natural Metabolism: New Sustainable Possibilities for Selective Organic Synthesis

Biomass-derived C6-furanic compounds have become the cornerstone of sustainable technologies. The key feature of this field of chemistry is the involvement of the natural process only in the first step, i.e., the production of biomass by photosynthesis. Biomass-to-HMF (5-hydroxymethylfurfural) conversion and further transformations are carried out externally with the involvement of processes with poor environmental factors (E-factors) and the generation of chemical wastes. Due to widespread interest, the chemical conversion of biomass to furanic platform chemicals and related transformations are thoroughly studied and well-reviewed in the current literature. In contrast, a novel opportunity is based on an alternative approach to consider the synthesis of C6-furanics inside living cells using natural metabolism, as well as further transformations to a variety of functionalized products. In the present article, we review naturally occurring substances containing C6-furanic cores and focus on the diversity of C6-furanic derivatives, occurrence, properties and synthesis. From the practical point of view, organic synthesis involving natural metabolism is advantageous in terms of sustainability (sunlight-driven as the only energy source) and green nature (no eco-persisted chemical wastes).

Anti-phytopathogenic-bacterial fatty acids from the mycelia of the edible mushroom Agaricus blazei

Five compounds including a new compound (1) were isolated from mycelia of a mushroom-forming fungus Agaricus blazei. Compound 2 was isolated from nature for the first time. Their structures were determined by the interpretation of spectroscopic data. In the bioassay examining growth inhibitory activity against phytopathogenic bacteria Clavibacter michiganensis, Burkholderia glumae, and Peptobacterium carotovorum, all the compounds showed inhibition effects on C. michiganensis. Compounds 3 and 4 also showed weak inhibitory activity against growth of B. glumae.

Plant growth regulators from mushrooms

Plants interact with fungi in their natural growing environments, and relationships between plants and diverse fungal species impact plants in complex symbiotic, parasitic, and pathogenic ways. Over the past 10 years, we have intensively investigated plant growth regulators produced by mushrooms, and we succeeded in finding various regulators from mushroom-forming fungi: (1) fairy chemicals as a candidate family of new plant hormones from Lepista sordida, (2) agrocybynes A to E from fungus Agrocybe praecox that stimulate strawberry growth, (3) armillariols A to C and sesquiterpene aryl esters from genus Armillaria that are allelopathic and cause Arimillaria root disease, and (4) other plant growth regulators from other mushrooms, such as Stropharia rugosoannulata, Tricholoma flavovirens, Hericium erinaceus, Leccinum extremiorientale, Russula vinosa, Pholiota lubrica and Cortinarius caperatus.