A concise total synthesis and PPAR activation activity of hericerin from Hericium erinaceum

The chemical structures, biosynthesis, and biological activities of secondary metabolites from the culinary-medicinal mushrooms of the genus Hericium: a review

Fungal phytochemicals derived from higher fungi, particularly those from the culinary-medicinal genus Hericium, have gained significant attention in drug discovery and healthcare. This review aims to provide a comprehensive analysis of the chemical structures, biosynthetic pathways, biological activities, and pharmacological properties of monomeric compounds isolated from Hericium species. Over the past 34 years, 253 metabolites have been identified from various Hericium species, including cyathane diterpenes, alkaloids, benzofurans, chromenes, phenols, pyrones, steroids, and other miscellaneous compounds. Detailed investigations into the biosynthesis of erinacines, a type of cyathane diterpene, have led to the discovery of novel cyathane diterpenes. Extensive research has highlighted the biological activities and pharmacological properties of Hericium-derived compounds, with particular emphasis on their neuroprotective and neurotrophic effects, immunomodulatory capabilities, anti-cancer activity, antioxidant properties, and antimicrobial actions. Erinacine A, in particular, has been extensively studied. Genomic, transcriptomic, and proteomic analyses of Hericium species have facilitated the discovery of new compounds and provided insights into enzymatic reactions through genome mining. The diverse chemical structures and biological activities of Hericium compounds underpin their potential applications in medicine and as dietary supplements. This review not only advances our understanding of Hericium compounds but also encourages further research into Hericium species within the realms of medicine, health, functional foods, and agricultural microbiology. The broad spectrum of compound types and their diverse biological activities present promising opportunities for the development of new pharmaceuticals and edible products.

Natural products in atherosclerosis therapy by targeting PPARs: a review focusing on lipid metabolism and inflammation

Inflammation and dyslipidemia are critical inducing factors of atherosclerosis. Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors and control the expression of multiple genes that are involved in lipid metabolism and inflammatory responses. However, synthesized PPAR agonists exhibit contrary therapeutic effects and various side effects in atherosclerosis therapy. Natural products are structural diversity and have a good safety. Recent studies find that natural herbs and compounds exhibit attractive therapeutic effects on atherosclerosis by alleviating hyperlipidemia and inflammation through modulation of PPARs. Importantly, the preparation of natural products generally causes significantly lower environmental pollution compared to that of synthesized chemical compounds. Therefore, it is interesting to discover novel PPAR modulator and develop alternative strategies for atherosclerosis therapy based on natural herbs and compounds. This article reviews recent findings, mainly from the year of 2020 to present, about the roles of natural herbs and compounds in regulation of PPARs and their therapeutic effects on atherosclerosis. This article provides alternative strategies and theoretical basis for atherosclerosis therapy using natural herbs and compounds by targeting PPARs, and offers valuable information for researchers that are interested in developing novel PPAR modulators.

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.

Dietary regulation of peroxisome proliferator-activated receptors in metabolic syndrome

BACKGROUND

Peroxisome proliferator-activated receptors (PPARs) are a class of ligand-activated nuclear transcription factors, members of the type nuclear receptor superfamily, with three subtypes, namely PPARα, PPARβ/δ, and PPARγ, which play a key role in the metabolic syndrome. In the past decades, a large number of studies have shown that natural products can act by regulating metabolic pathways mediated by PPARs.

PURPOSE

This work summarizes the physiological importance and clinical significance of PPARs and reviews the experimental evidence that natural products mediate metabolic syndrome via PPARs.

METHODS

This study reviews relevant literature on clinical trials, epidemiology, animals, and cell cultures published in NCBI PubMed, Scopus, Web of Science, Google Scholar, and other databases from 2001 to October 2022. Search keywords were "natural product" OR "botanical" OR "phytochemical" AND "PPAR" as well as free text words.

RESULTS

The modulatory involvement of PPARs in the metabolic syndrome has been supported by prior research. It has been observed that many natural products can treat metabolic syndrome by altering PPARs. The majority of currently described natural compounds are mild PPAR-selective agonists with therapeutic effects that are equivalent to synthetic medicines but less harmful adverse effects.

CONCLUSION

PPAR agonists can be combined with natural products to treat and prevent metabolic syndrome. Further human investigations are required because it is unknown how natural products cause harm and how they might have negative impacts.

De novo Assembly of the Benzenoid Ring as a Core Strategy for Synthesis of the Isoindolinone Natural Products Isohericerin, Erinacerin A, and Sterenin A

Here we describe the use of the hexadehydro-Diels-Alder (HDDA) reaction for the de novo construction of the isoindolinone scaffold and its application to the synthesis of the title natural products. The key isoindolinone-forming HDDA reaction involved an unprecedented substrate motif in which an amide carbonyl group was conjugated to the 4π 1,3-diyne component. In addition, a dimethylsilyl (-SiMe₂H) substituent was exploited to trigger a Fleming-Tamao-Kumada oxidation for the installation of an essential phenolic hydroxyl group.

Total Synthesis, Structure Revision, and Neuroprotective Effect of Hericenones C-H and Their Derivatives

The first total syntheses of hericenones C-H and "putative 3-hydroxyhericenone F" were achieved. Highlights of the synthesis include the straightforward construction of the resorcinol core and geranyl side chain, assembly of the natural product skeleton by sequential O-geranylation and a clay/zeolite-mediated O → C rearrangement reaction, and a biomimetic cyclization to form a variety of bicyclic natural hericenones and their congeners. The structure of the "putative 3-hydroxyhericenone F" was revised as the 5-exo cyclization product (named: hericenone Z) of epoxyhericenone C through in-depth analyses of the cyclization modes in addition to NMR spectroscopic studies. To gain insights into the biological functions of geranyl-resorcinols in Hericium erinaceus, potential neuroprotective effects against endoplasmic reticulum (ER) stress-dependent cell death were evaluated systematically to clarify a fundamental structure-activity relationship. Among the compounds assayed, the linoleate-containing hericenone analogue, i.e., the regioisomer of hericene D, was found to possess the most potent neuroprotective effect against tunicamycin and thapsigargin-induced ER stress-dependent cell death.