Honokiol and magnolol: A review of structure-activity relationships of their derivatives.

Honokiol (HK) and magnolol (MAG) are typical representatives of neolignans possessing a wide range of biological activities and are employed as traditional medicines in Asia. In the past few decades, HK and MAG have been proven to be promising chemical scaffolds for the development of novel neolignan drugs. This review focuses on recent advances in the medicinal chemistry of HK and MAG derivatives, especially their structure-activity relationships. In addition, it also presents a comprehensive summary of the pharmacology, biosynthetic pathways, and metabolic characteristics of HK and MAG. This review can provide pharmaceutical chemists deeper insights into medicinal research on HK and MAG, and a reference for the rational design of HK and MAG derivatives.

A new tetracyclic triterpenoid from endophytic fungus Fusarium sporotrichioides.

Objective: To isolate bioactive compounds from the endophytic fungus Fusarium sporotrichioides isolated from Rauwolfia yunnanensis, and investigate their pharmacological activities. Methods: The chemical constituents were isolated and purified by combining with ODS column chromatography, silica gel column chromatography and by performing semipreparative HPLC. Their structures were established on the basis of 1D NMR (1H-NMR and 13C-NMR) and 2D NMR (1H-1H COSY, HSQC, HMBC and NOESY), as well as HRESIMS and comparison with literature data. In addition, the absolute configuration of compound 1 was determined by calculated ECD data. Results: One previously undescribed tetracyclic triterpenoid derivative, named as integracide L (1), 12α-acetoxy-4,4-dimethyl-24-methylene-5α-cholesta-8,14-diene-2α,3ß,11ß-triol (2), 12α-acetoxy-4,4-dimethyl-24-methylene-5α-cholesta-8-momoene-2α,3ß,11ß-triol (3), 12α-acetoxy-4,4-dimethyl-24-methylene-5α-cholesta-8,14-diene-3ß,11ß-triol (4), and 12α-acetoxy-4,4-dimethyl-24-methylene-5α-cholesta-8-momoene-3ß,11ß-triol (5) were isolated from F. sporotrichioide. Moreover, compound 1 was rare tetracyclic triterpenoid with single methyl replacement at C-4 position. Conclusion: Compound 1 was a new tetracyclic triterpenoid isolated from the endophytic fungus F. sporotrichioides. In addition, compound 2 could inhibit the growth of three different human cancer cells significantly. Compounds 3 and 5 were found to possess better cytotoxic activities on HepG-2 cells than the other compounds, with IC50 values of (2.8 ± 0.1) and (6.3 ± 0.3) µmol/L respectively.

Recent advances on cyclodepsipeptides: biologically active compounds for drug research.

Cyclodepsipeptides are a large family of peptide-related natural products consisting of hydroxy and amino acids linked by amide and ester bonds. A number of cyclodepsipeptides have been isolated and characterized from fungi and bacteria. Most of them showed antitumor, antifungal, antiviral, antimalarial, and antitrypanosomal properties. Herein, this review summarizes the recent literatures (2010-2022) on the progress of cyclodepsipeptides from fungi and bacteria except for those of marine origin, in order to enrich our knowledge about their structural features and biological sources.

A rare tetrahydroimidazopyridine from the marine-derived fungus Paraconiothyrium sp. YK-03.

A new tetrahydroimidazopyridine named butyl (5R,6R,7S,8S)-5,6,7,8-tetrahydro-6,7,8-trihydroxy-5-(hydroxymethyl)imidazo[1,2-a]pyridine-2-carboxylate(1), together with eight known compounds (2-9), were isolated from the fermentation broth of a marine-derived fungus Paraconiothyrium sp. YK-03. Their chemical structures were elucidated by extensive analysis of one-dimensional and two-dimensional NMR spectroscopy, HR-ESIMS and optical rotation. Among these compounds, compound 1 represented a rare tetrahydroimidazopyridine, and compounds 2-7 were isolated from the Paraconiothyrium species for the first time. A plausible biosynthetic pathway for compound 1 was proposed.

Lignan glycosides from Fritillaria verticillata Willd. and their anti-inflammatory activities.

Three undescribed lignan glycosides, echiunines E-G (1-3), as well as eight known compounds (4-11) were isolated from Fritillaria verticillata Willd. Among them, compounds 1-3 were a series of lignan glycosides reported for the first time from genus Fritillaria. Their structures were elucidated by analyses of extensive spectroscopic data and comparison of the NMR data with those reported previously, the absolute configuration of compounds were further confirmed by calculated ECD method. The NO release inhibitory effects of compounds were evaluated in LPS-activated RAW264.7 macrophages. Compounds 7-8 showed inhibitory acitivities in a dose-dependent manner.

Santalane-type sesquiterpenoids and isobenzofuranones from cultures of Paraconiothyrium sporulosum YK-03.

Three undescribed santalane-type sesquiterpenoids (parasantalenoic acids A-C) and two undescribed epimeric isobenzofuranones (paraphthalides A and B) were isolated from cultures of the marine mud-associated fungus Paraconiothyrium sporulosum YK-03. Their structures were elucidated by analysis of the extensive spectroscopic and crystal X-ray diffraction data, combined with ECD calculations and comparison. Santalane-type sesquiterpenoids have been firstly found in the Paraconiothyrium species. Parasantalenoic acids A-C represent three rare polyhydroxylated santalane-type sesquiterpenoid carboxylic acids, and parasantalenoic acid A represents the first example of 2-chlorinated santalane-type sesquiterpenoid. A plausible biosynthetic pathway for parasantalenoic acids A-C was proposed. Additionally, the anti-neuroinflammatory activities of parasantalenoic acids A-C were investigated by evaluating their inhibitory effects on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated BV-2 microglia cells. Among them, parasantalenoic acid C showed significant anti-neuroinflammatory activity with an inhibition of 86.45 ± 2.45% at 10 µM.

Cytotoxic Cyclodepsipeptides and Cyclopentane Derivatives from a Plant-Associated Fungus Fusarium sp.

In this work, four new cyclodepsipeptides, fusarihexins C-E (1-3) and enniatin Q (4), four new cyclopentane derivatives, fusarilins A-D (5-8), together with eight known compounds (9-16), were isolated from cultures of the endophytic fungus Fusarium sp. The structures of the isolated compounds were elucidated by analysis of HRMS and NMR spectroscopic data. The absolute configurations were determined using Marfey's method, a modified Mosher's method, single-crystal X-ray diffraction analysis, and ECD analysis. The antitumor activities of the isolated compounds in vitro were evaluated. Cyclodepsipeptides displayed cytotoxicities against the Huh-7, MRMT-1, and HepG-2 cell lines. Compounds 4, 9, 10, and 12 with IC50 values of 1.0-9.1 µM exhibited the most potent cytotoxicities against the three cell lines as compared to the positive control-5-fluorouracil. Compounds 1-3 and 11 exhibited moderate cytotoxic activities (IC50 values of 10.7-20.1 µM).

Twelve New Seco-Pregnane Glycosides from Cynanchum taihangense.

For our interest in the potential biologically active and structurally unique steroidal glycosides, continued phytochemical investigation of Cynanchum taihangense was carried out; twelve new seco-pregnane glycosides, cynataihosides I-L (1-4), M-T (7-14), and two known glycosides, glaucoside A (5) and atratcynoside F (6), were isolated from the 95% ethanol extract of Cynanchum taihangense. Two new aglycones were found among compounds 10, 11, 13, and 14. The structures of the glycosides were elucidated based on 1D and 2D NMR spectroscopic data, HR-ESI-MS analysis, and chemical evidence. The cytotoxicity of compounds against three human tumor cell lines (HL-60, THP-1, and PC-3) were evaluated by MTT assay. Compound 11 displayed significant cytotoxicity against THP-1 and PC-3 cell line with IC50 values of 5.08 and 22.75 µm, respectively. Compounds 3 and 14 exhibited moderate and selective cytotoxicity on HL-60 and THP-1 with IC50 values of 17.78 and 16.02 µm, respectively.

Recent advances in medicinal chemistry of oleanolic acid derivatives.

Oleanolic acid (OA), a ubiquitous pentacyclic oleanane-type triterpene isolated from edible and medicinal plants, exhibits a wide spectrum of pharmacological activities and tremendous therapeutic potential. However, the undesirable pharmacokinetic properties limit its application and development. Numerous researches on structural modifications of OA have been carried out to overcome this limitation and improve its pharmacokinetic and therapeutic properties. This review aims to compile and summarize the recent progresses in the medicinal chemistry of OA derivatives, especially on structure-activity relationship in the last few years (2010-2021). It gives insights into the rational design of bioactive derivatives from OA scaffold as promising therapeutic agents.

Pyranone Derivatives With Antitumor Activities, From the Endophytic Fungus Phoma sp. YN02-P-3.

Two new pyranone derivatives phomapyrone A (2) and phomapyrone B (3), one new coumarin 11S, 13R-(+)-phomacumarin A (1), three known pyranones (4-6), together with three known amide alkaloids fuscoatramides A-C (7-9), as well as 9S, 11R-(+)-ascosalitoxin (10) were isolated from the endophytic fungus Phoma sp. YN02-P-3, which was isolated from the healthy leaf tissue of a Paulownia tree in Yunnan Province, China. Their structures were elucidated using extensive NMR spectroscopic and HRESIMS data and by comparing the information with literature data. In addition, all compounds were tested for their cytotoxicity activity against human tumor cell lines, and the results showed that new compounds 1-3 showed moderate inhibitory activity against the HL-60 cell line with IC50 values of 31.02, 34.62, and 27.90 µM, respectively.

Structure Elucidation and Anti-Tumor Activities of Trichothecenes from Endophytic Fungus Fusariumsporotrichioides.

The secondary metabolites of Fusarium sporotrichioides, an endophytic fungus with anti-tumor activity isolated from Rauvolfia yunnanensis Tsiang, were investigated. Five trichothecenes, including one previously undescribed metabolite, were isolated and identified. Their structures were elucidated by means of extensive spectroscopic methods; the absolute configuration of compound 1 was determined by the ECD method. Surprisingly, 8-n-butyrylneosolaniol (3) exhibited stronger anti-tumor activity than T-2 toxin against Huh-7 cell line, with an IC50 value of 265.9 nM. 8-n-butyrylneosolaniol (3) promoted apoptosis induction in Huh-7 cells. Moreover, cell cycle analysis showed that cell cycle arrest caused by 8-n-butyrylneosolaniol (3) at the G2/M phase resulted in cell proliferation inhibition and pro-apoptotic activity. Further studies showed a significant decrease in mitochondrial membrane permeabilization and a significant increase in ROS generation, which led to the activation of caspase cascades and subsequent cleavage of PARP fragments. In conclusion, 8-n-butyrylneosolaniol (3) induced cell apoptosis in Huh-7 cells via the mitochondria-mediated apoptotic signaling pathway, which could be a leading compound for anti-tumor agents.

A novel strategy by integrating chemical profiling, molecular networking, chemical isolation, and activity evaluation to target isolation of potential anti-ACE2 candidates in Forsythiae Fructus.

BACKGROUND: Traditional Chinese medicine (TCM) is regarded as a large database containing hundreds to thousands of chemical constituents that can be further developed as clinical drugs, such as artemisinin in Artemisia annua. However, effectively exploring novel candidates is still a challenge faced by researchers. PURPOSE: In this work, an integrated strategy combining chemical profiling, molecular networking, chemical isolation, and activity evaluation (CMCA strategy) was proposed and applied to systematically characterize and screen novel candidates, and Forsythiae fructus (FF) was used as an example. STUDY DESIGN: It contained four parts. First, the chemical compounds in FF were detected by ultra-high-performance liquid chromatography-mass spectrometry (UPLC/Q-TOF MS) with data-dependent acquisition, and further, the targeted compounds were screened out based on an in-house database. In the meantime, the representative MS/MS fragmentation behaviors of different chemical structure types were summarized. Second, homologous constituents were grouped and organized based on feature-guided molecular networking, and the nontargeted components with homologous mass fragmentation behaviors were characterized. Third, the novel compounds were isolated and unambiguously identified by nuclear magnetic resonance (NMR). Finally, the anti-angiotensin-converting enzyme 2 (ACE2) activities of isolated chemical constituents were further evaluated by in vitro experiments. RESULTS: A total of 278 compounds were profiled in FF, including 151 targeted compounds and 127 nontargeted compounds. Among them, 16 were unambitiously identified by comparison with reference standards. Moreover, 25 were classified into potential novel compounds. Two novel compounds were unambiguously identified by using conventional chromatographic methods, and they were named phillyrigeninside D (peak 254) and forsythenside O (peak 155). Furthermore, the ACE2 activity of the compounds in FF was evaluated by modern pharmacological methods, and among them, suspensaside A was confirmed to present obvious anti-ACE2 activity. CONCLUSION: Our work provides meaningful information for revealing potential FF candidates for the treatment of COVID-19, along with new insight for exploring novel candidates from complex systems.

A new diterpernoid glycoside from the fruit of Forsythia suspensa.

One new diterpernoid glycoside, lanceolatinoside A (1), together with one known iridoid glycoside, luzonoside C (2) were isolated from the fruit of Forsythia suspensa. The structure of the new compound (1) was elucidated through 1 D and 2 D NMR spectroscopic data, and HR-ESIMS. Compound 2 was identified as luzonoside C (2) on the basis of NMR spectroscopic data analyses and comparison with those reported in the literature.

Polyhydroxylated bergamotane-type sesquiterpenoids from cultures of Paraconiothyrium sporulosum YK-03 and their absolute configurations.

Eight undescribed polyhydroxylated bergamotane-type sesquiterpenoids with bicyclic, tricyclic and tetracyclic systems, namely sporulamides A-D, sporulosoic acids A-B and sporuloketals A-B, along with three known analogs were isolated from cultures of the marine mud-associated fungus Paraconiothyrium sporulosum YK-03. The chemical structures of these sesquiterpenoids were elucidated by the extensive spectroscopic techniques of NMR and HR-ESI-MS. Assisted by the X-ray crystallography analysis and electronic circular dichroism (ECD) spectroscopic calculation and comparison, their absolute configurations were established. Sporuloketals A-B represent two rare tetracyclic bergamotanes. It's the first time that ECD empirical rules have been successfully verified and applied for determining the absolute configurations of these bergamotane-type sesquiterpenoids.

7-Hydroxy questin, a new anthraquinone from a wetland fungus Aspergillus flavipes PJ03-11.

One new anthraquinone, questinlin (1), four known anthraquinones (2-5), together with three known benzophenone derivatives (6-8) were isolated from a wetland fungus Aspergillus flavipes PJ03-11. Their structures were elucidated on the basis of detailed spectroscopic analysis, including 1D, 2D NMR (HMQC, HMBC), mass spectrometry, and optical rotation and IR spectra. In addition, the cytotoxic activities against three human cancer cell lines (HepG2, Caco-2 and A549) were evaluated. In this article, Aspergillus flavipes PJ03-11, a wetland soil fungus isolated from Honghaitan, Panjin city, Liaoning province, was used to study the secondary metabolites through one strain many compounds (OSMAC) methods. By changing the culture medium and adding the substance stimulating the metabolism of the strain into the fermentation medium, the peak type and amount of ethyl acetate extract in the fermentation medium were studied by HPLC. Finally, 2 mM MgCl2 was added into the rice solid medium for the expansion fermentation.

Dissection of the Functional Mechanism of Human Gut Bacterial Strain AD16 by Secondary Metabolites' Identification, Network Pharmacology, and Experimental Validation.

Gut microbiota plays important roles in several metabolic processes, such as appetite and food intake and absorption of nutrients from the gut. It is also of great importance in the maintenance of the health of the host. However, much remains unknown about the functional mechanisms of human gut microbiota itself. Here, we report the identification of one anticancer gut bacterial strain AD16, which exhibited potent suppressive effects on a broad range of solid and blood malignancies. The secondary metabolites of the strain were isolated and characterized by a bioactivity-guided isolation strategy. Five new compounds, streptonaphthalenes A and B (1-2), pestaloficins F and G (3-4), and eudesmanetetraiol A (5), together with nine previously known compounds, were isolated from the effective fractions of AD16. Structures of the new compounds were established by 1D and 2D NMR and MS analysis, and the absolute configurations were determined by the CD method. The analysis of network pharmacology suggested that 3, 2, and 13 could be the key components for the anti-NSCLC activity of AD16. In addition to the PI3K-Akt signaling pathway, the proteoglycans in cancer pathway could be involved in the anti-NSCLC action of AD16.

New Cytotoxic Cytochalasans from a Plant-Associated Fungus Chaetomium globosum kz-19.

Four new cytochalasans, phychaetoglobins A-D (1-4), together with twelve known cytochalasans (5-16), were isolated from a mangrove-associated fungus Chaetomium globosum kz-19. The new structures were elucidated on the basis of extensive 1D and 2D NMR, HR ESIMS spectroscopic analyses, and electronic circular dichroism (ECD) calculations. The absolute configuration of 2 was established by application of Mosher's method. Compounds 4-8 exhibited moderate cytotoxicities against A549 and HeLa cell lines with the IC50 values less than 20 µM.

Novel glutamic acid derivatives from the bulbs of Fritillaria verticillate Willd and their antitumor activities.

Four previously undescribed glutamic acid derivatives, verticillamines A-D (1-4), together with six known compounds (5-10) were isolated from the bulbs of Fritillaria verticillate Willd. The structures of (1-10) were established on the basis of UV, IR, MS, 1D and 2D NMR, and the absolute configurations of compounds (1-4) were determined by calculated ECD methods. Among them, compounds (1-3) were rare 2-methyl-γ-lactam alkaloid derivatives. Moreover, both γ-lactam alkaloids (1-5) and pyrrolidine alkaloids (6-7) were discovered in Fritillaria for the first time. Compound 8 exhibited moderate cytotoxic activities against A2780 and HepG 2 cells, with IC50 values of 11.7 ± 5.2 µM and 25.6 ± 2.8 µM.

Xanthones and anthraquinones from the soil fungus Penicillium sp. DWS10-P-6.

Two new xanthones, oxisterigmatocystins J and K (1-2), and two new anthraquinones, versicolorins D and E (3-4), were isolated from solid cultures of the fungus Penicillium sp. DWS10-P-6, together with twelve known compounds (5-16). Their structures, including their absolute configurations, were characterized on the basis of extensive 1D NMR, 2D NMR, MS and CD spectral data. The cytotoxic activities of compounds 1-12 against HL-60, MDA-MB-231 and PC-3 cells were also evaluated. Compounds 4 and 5 showed significant cytotoxic activity against the HL-60 cell line with IC50 values of 1.65 µM and 1.05 µM, respectively.

Two new pregnane steroidal glycosides from Cynanchum taihangense.

As our ongoing chemical investigation, two new pregnane steroidal glycosides, cynataihosides G (1), with a new aglycone, and H (2) were isolated from the 95% ethanol extract of Cynanchum taihangense. Their structures were elucidated on the basis of 1 D and 2 D NMR spectral data, HR-ESI-MS analysis and qualitative chemical methods. The compounds were subjected to detect the cytotoxicity against three human tumor cell lines (HL-60, THP-1 and PC-3). The compounds displayed no significant cytotoxicity.Supplemental data for this article can be accessed at https://doi.org/10.1080/14786419.2019.1672682.