Antimicrobial Acylphloroglucinol Meroterpenoids and Acylphloroglucinols from Dryopteris crassirhizoma

New acylphloroglucinol-sesquiterpenoid adducts with antiviral activities from Dryopteris atrata

Seven novel acylphloroglucinol-sesquiterpenoid adducts, designated as dryatraols J-P (1-7), were isolated from the rhizomes of Dryopteris atrata (Wall. ex Kunze) Ching. The structures, including absolute configurations, were elucidated using comprehensive spectroscopic data, calculated 13C Nuclear Magnetic Resonance-Diastereotopic Probability Assignment Plus (13C NMR-DP4+) probability analysis, and ECD calculations. These structures represent a rare subclass of carbon skeleton of acylphloroglucinol-sesquiterpenoid adducts with a furan ring connecting the acylphloroglucinol and sesquiterpenoid moieties. Notably, compounds 1-6 are the first reported examples of acylphloroglucinol-sesquiterpenoid adducts with dimeric acylphloroglucinol incorporated into the aristolane- or rulepidanol-type sesquiterpene, while compound 7 features a hydroxylated monomeric acylphloroglucinol motif. A preliminary evaluation of their antiviral activities revealed that compounds 1-6 exhibited more potent activities against respiratory syncytial virus (RSV) with IC50 values ranging from 0.75 to 3.12 μmol·L-1 compared to the positive control (ribavirin).

Filicinic Acid-Based Meroterpenoids with Antiproliferative Activity against Prostate Cancer PC-3 Cells from Dryopteris wallichiana

Nine new structurally diverse filicinic acid-based meroterpenoids (1-9) with four kinds of carbon skeletons were isolated from the rhizomes of Dryopteris wallichiana. Their structures, including the absolute configurations, were elucidated by comprehensive analysis of spectroscopic data, quantum chemical calculations, and single-crystal X-ray diffraction. Structurally, compounds 1-4 feature an unprecedented 6/6/5/6/6/6 hexacyclic system with a rare oxaspiro[4.5]decane core linking the filicinic acid and ent-kaurane-type diterpene moieties. Compounds 5-6 are rare hybrids of filicinic acid and carotane-type sesquiterpene. Compound 7 is an unusual rearranged filicinic acid-carotane-type sesquiterpene meroterpenoid. Compounds 8-9 are two enantiomeric pairs of new meroterpenoids constructed by filicinic acid and a germarane-type sesquiterpene. A plausible biosynthetic pathway for the nine compounds was proposed. Notably, compounds 5, 6, (+)/(-)-8, and (+)/(-)-9 were discovered to possess antiproliferative activity against PC-3 cells based on virtual screening, and in vitro bioassay. An interactive preprint version of the article can be found at https://www.authorea.com/doi/full/10.22541/au.172666991.17272585/v1.

Isolation and biomimetic synthesis of acylphloroglucinol meroterpenoids as anti-breast cancer agents from Dryopteris crassirhizoma

Two new acylphloroglucinol-nerolidol meroterpenoids (APNMs) [(±)-1 and (±)-2], with a skeleton of mixed sesquiterpene and dimeric acylphloroglucinol biosynthetic origin, were isolated from the medicinal pteridophyte Dryopteris crassirhizoma. Inspired by the proposed biosynthetic pathway, we initially completed the biomimetic syntheses of eight optically active Dryopteris APNMs (1-8) in a one-pot domino reaction. The structures of APNMs 1-8 including their absolute configurations were unambiguously established by a combination of NMR analysis, ECD calculations, and synthetic methods. Furthermore, an underlying method based on NMR data to assign the stereochemistry of the long-chain alcohol moieties in APNMs was revealed. Anti-triple negative breast cancer (anti-TNBC), antifungal and antibacterial activities of the synthetic meroterpenoids were evaluated. All tested compounds exhibited cytotoxicity against TNBC cells MDA-MB-231 with IC50 values in the range of 1.22-27.43 μM, with (-)-8 being the most potent antitumor agent (IC50: 0.48 μM; selectivity index: 32.04). This study resulted in the biomimetic synthesis of APNMs for the first time and positioned APNMs from D. crassirhizoma as a new class of promising candidates for the development of new anti-TNBC drugs.

Phytochemical constituents from rhizomes of Dryopteris crassirhizoma and their anti-inflammatory activity

The phytochemical investigation on the rhizomes of Dryopteris crassirhizoma (Dryopteridaceae) resulted in the discovery of one novel compound, drycrassirhizomamide A (1), and one new natural product, drycrassirhizomamide B (2), as well as four known isolates, (S)-(-)-N-benzoylphenylalaninol (3), blumenol A (4), 8-C-glucosylnoreugenin (5), and dryopteroside (6). Their chemical structures were identified by NMR and mass spectroscopy. Compounds 1-2 were determined to be 1,19-diethyl 10-oxo-2,9,11,18-tetraazanonadecanedioate and C,C'-diethyl N,N'-1,6-hexanediylbis[carbamate]. The anti-inflammatory activities of these compounds were evaluated with LPS-stimulated RAW264.7 macrophage and BV2 microglia. The results showed that compounds 1-3 and 6 have inhibitory effects of NO production with IC50 values of 13.41, 30.36, 25.51, and 11.35 μM in LPS-stimulated RAW264.7 cells. Also, compounds 1 and 4-6 have abilities to inhibit NO production with the IC50 values of 40.11, 30.94, 15.76, and 16.79 μM in BV2 cells, which demonstrated that they may possess the potential anti-inflammatory activity.

Insights into Chemical Diversity and Potential Health-Promoting Effects of Ferns

The scientific community is focusing on how to enhance human health and immunity through functional foods, and dietary supplements are proven to have a positive as well as a protective effect against infectious and chronic diseases. Ferns act as a taxonomical linkage between higher and lower plants and are endowed with a wide chemical diversity not subjected to sufficient scrutinization before. Even though a wealth of traditional medicinal fern uses were recorded in Chinese medicine, robust phytochemical and biological investigations of these plants are lacking. Herein, an extensive search was conducted using the keywords ferns and compounds, ferns and NMR, ferns and toxicity, and the terms ferns and chemistry, lignans, Polypodiaceae, NMR, isolation, bioactive compounds, terpenes, phenolics, phloroglucinols, monoterpenes, alkaloids, phenolics, and fatty acids were utilized with the Boolean operators AND, OR, and NOT. Databases such as PubMed, Web of Science, Science Direct, Scopus, Google Scholar, and Reaxys were utilized to reveal a wealth of information regarding fern chemistry and their health-promoting effects. Terpenes followed by phenolics represented the largest number of isolated active compounds. Regarding the neuroprotective effects, Psilotium, Polypodium, and Dryopteris species possessed as their major phenolics component unique chemical moieties including catechins, procyanidins, and bioflavonoids. In this updated chemical review, the pharmacological and chemical aspects of ferns are compiled manifesting their chemical diversity in the last seven years (2017-2024) together with a special focus on their nutritive and potential health-promoting effects.

Dryopteris crassirhizoma Nakai.: A review of its botany, traditional use, phytochemistry, pharmacological activity, toxicology and pharmacokinetics

ETHNOPHARMACOLOGICAL RELEVANCE

The Dryopteris crassirhizoma Nakai., a commonly used herb, is known as "Guan Zhong" in China, "Oshida" in Japan and "Gwanjung" in Korea. It has long been used for parasitic infestation, hemorrhages and epidemic influenza.

AIM OF THE REVIEW

The present paper aims to provide an up-to-date review at the advancements of the investigations on the traditional use, phytochemistry, pharmacological activity, toxicology and pharmacokinetics of D. crassirhizoma. Besides, possible trends, therapeutic potentials, and perspectives for future research of this plant are also briefly discussed.

MATERIALS AND METHODS

Relevant information on traditional use, phytochemistry, pharmacological activity, toxicology and pharmacokinetics of D. crassirhizoma was collected through published materials and electronic databases, including the Chinese Pharmacopoeia, Flora of China, Web of Science, PubMed, Baidu Scholar, Google Scholar, and China National Knowledge Infrastructure. 109 papers included in the article and we determined that no major information was missing after many checks. All authors participated in the review process for this article and all research paper are from authoritative published materials and electronic databases.

RESULTS

130 chemical components, among which phloroglucinols are the predominant groups, have been isolated and identified from D. crassirhizoma. D. crassirhizoma with its bioactive compounds is possessed of extensive biological activities, including anti-parasite, anti-microbial, anti-viral, anti-cancer, anti-inflammatory, anti-oxidant, anti-diabetic, bone protective, immunomodulatory, anti-platelet and anti-hyperuricemia activity. Besides, D. crassirhizoma has special toxicology and pharmacokinetics characterization.

CONCLUSIONS

D. crassirhizoma is a traditional Chinese medicine having a long history of application. This review mainly summarized the different chemical components extract from D. crassirhizoma and various reported pharmacological effects. Besides, the toxicology and pharmacokinetics of D. crassirhizoma also be analysed in this review. However, the chemical components of D. crassirhizoma are understudied and require further research to expand its medicinal potential, and it is urgent to design a new extraction scheme, so that the active ingredients can be obtained at a lower cost.