Ganotheaecolin A, a Neurotrophic Conjugated Ergosterol with a Naphtho[1,8-ef]azulene Scaffold from Ganoderma theaecolum

Chemical constituents from the fruiting bodies of Lanmaoa asiatica and their anti-inflammatory activity

Four new compounds, dimethyl 3,5-bis(4-hydroxyphenyl)-1H-pyrrole-2,4-dicarboxylate (1), dimethyl 3,5-bis(4-hydroxyphenyl)-1H-furan-2,4-dicarboxylate (2), 5α-hydroxy-6β-methoxy-ergosta-7,22E-dien-3-one (3), and 6-methoxy-strophasterol E (4), together with sixteen known compounds (5-20), were isolated from the fruiting bodies of Lanmaoa asiatica. The structures of new compounds were elucidated by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculation. Among them, compounds 2, 4, 7, and 9 exhibited anti-inflammatory activity by suppressing NO production in lipopolysaccharide-stimulated RAW264.7 macrophages with IC50 values ranging from 20.3 to 47.3 μM.

Microascusteroids A and B, two 5,6-seco-9,10-seco steroids with a C-ring rearranged ergostane skeleton from the marine-derived fungus Microascus sp. SCSIO 41821

Two undescribed steroids, microascusteroids A and B (1 and 2), together with four known compounds (3-6) were isolated from the marine-derived fungal strain Microascus sp. SCSIO 41821. The structures of 1 and 2 were determined by extensive spectroscopic analysis, and their absolute configurations were established by quantum chemical calculations of electronic circular dichroism (ECD) spectra. Specially, compounds 1 and 2 were unusual 5,6-seco-9,10-seco steroids with a C-ring rearranged ergostane skeleton. In addition, 1 and 2 showed medium inhibition activity against lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells and displayed mild enzyme inhibitory activity against PTP1B and cytotoxicity against human cancer cell lines H1975 and HepG2.

Neuroprotective and antidiabetic lanostane-type triterpenoids from the fruiting bodies of Ganoderma theaecolum

Eight previously undescribed lanostane triterpenoids, including five nortriterpenoids with 26 carbons, ganothenoids A-E (1-5), and three lanostanoids, ganothenoids F-H (6-8), along with 24 known ones (9-32), were isolated from the fruiting bodies of Ganodrma theaecolum. The structures of the novel compounds were elucidated using comprehensive spectroscopic methods, including electronic circular dichroism (ECD) and nuclear magnetic resonance (NMR) calculations. Compounds 1-32 were assessed for their neuroprotective effects against H2O2-induced damage in human neuroblastoma SH-SY5Y cells, as well as their inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) and α-glucosidase. Compound 4 demonstrated the most potent neuroprotective activity against H2O2-induced oxidative stress by suppressing G0/G1 phase cell cycle arrest, reducing reactive oxygen species (ROS) levels, and inhibiting cell apoptosis through modulation of B-cell lymphoma 2 protein (Bcl-2) and Bcl-2 associated X-protein (Bax) protein expression. Compounds 26, 12, and 28 exhibited PTP1B inhibitory activities with IC50 values ranging from 13.92 to 56.94 μmol·L-1, while compound 12 alone displayed significant inhibitory effects on α-glucosidase with an IC50 value of 43.56 μmol·L-1. Additionally, enzyme kinetic analyses and molecular docking simulations were conducted for compounds 26 and 12 with PTP1B and α-glucosidase, respectively.

Bipolaristeroid A, a 5,6-seco-9,10-seco-steroid with cytotoxic activity from the fungus Bipolaris maydis

Eleven undescribed steroids, bipolaristeroids A-K, and one known compound, demethylincisterol A3, were isolated from the fungus Bipolaris maydis. Bipolaristeroid A is a 5,6-seco-9,10-seco-steroid with a rearranged B ring, in which the A and C rings are connected by an ester bond. Bipolaristeroid B is a rearranged 1(10 → 6)-abeosteroid with an aromatic B ring. Their planar structures and absolute configuration were determined using NMR, HRESIMS, DP4+ analysis, ECD calculation, and single-crystal X-ray diffraction. Bipolaristeroid A shows excellent inhibitory effects against the cancer cell lines HepG2, A549, SW620, and C4-2B with IC50 values of 7.94, 5.11, 5.13, and 3.83 μM, respectively.

Masterpenoids A-D, Four Unprecedented Nortriterpenoids from the Mastic (Pistacia lentiscus) and Their Anti-inflammatory Activity

Four unprecedented nortriterpenoids, masterpenoids A-D, were isolated and fully elucidated from the resin of the mastic tree (Pistacia lentiscus). Masterpenoids A-C are the first norterpenoids featuring an unprecedented 6/6/6/10 ring system, while masterpenoid D possesses a novel 6/6/6/7/5 ring system. The anti-inflammatory potential of the compounds was meticulously assessed through the establishment of an in vitro model of lipopolysaccharide-induced inflammation in RAW264.7 macrophage cells. Among them, Masterpenoids A and D showed potent inhibition of NO production, with IC50 values of 10.6 ± 0.8 and 8.2 ± 0.9 μM, respectively, compared to positive control dexamethasone (IC50 = 23.2 ± 1.2 μM).

Ten ring-B aromatized ergosterols from Aspergillus spectabilis

Spectasterols F-O (1-10), ten interesting ergosterols with an aromatized B ring, were obtained from Aspergillus spectabilis. Their structures and absolute configurations were determined using a combination of high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), nuclear magnetic resonance (NMR) spectroscopy, single-crystal X-ray diffraction analyses, and electronic circular dichroism (ECD) calculations. Structurally, these aromatic ergosterols feature versatile side chains. Notably, compound aromatic ergosterols featured versatile side chains, and compound 4 is an unusual C23 ergosterol characterized by a shorter side chain due to oxidative cleavage between C-23 and C-24. All compounds were evaluated for their neuroprotective activities, with compound 8 showing a dose-dependent ability to reduce apoptosis and protect mitochondrial function in glutamate-induced SH-SY5Y cells.

Ergosterols with rare peroxide, oxetane ring moiety, and a lactone ring from Aspergillus spectabilis and their immunosuppressive activities

Ten ergostane-type steroids, including seven undescribed ones named spectasteroids A-G, were obtained from Aspergillus spectabilis. Their structures and absolute configurations were determined based on HRESIMS, NMR, ECD calculations, and single-crystal X-ray diffraction analyses. Structurally, spectasteroid A was a unique example of aromatic ergostane-type steroid that featured a rare peroxide ring moiety; spectasteroid B contained a rare oxetane ring system formed between C-9 and C-14; and spectasteroid C was an unusual 3,4-seco-ergostane steroid with an extra lactone ring between C-3 and C-9. Spectasteroids F and G specifically showed inhibitory effects against concanavalin A-induced T lymphocyte proliferation and lipopolysaccharide-induced B lymphocyte proliferation, with IC50 values ranging from 2.33 to 4.22 μM. Spectasteroid F also showed excellent antimultidrug resistance activity, which remarkable enhanced the inhibitory activity of PTX on the colony formation of SW620/Ad300 cells.

Immunosuppressive steroids quadrilisteroids A-C and derivatives from the terrestrial fungus Aspergillus quadrilineatus

Seven undescribed compounds (1-7) along with six known compounds (8-13) were isolated from Eurotiaceae Aspergillus quadrilineatus. Their structures and absolute configurations were elucidated by NMR, HRESIMS, and ECD calculations. Quadrilisteroids A (1) and B (2) possessed an unprecedented 6/5/6/6/6/5 hexacyclic ring system in conjugation with a highly fused benzene ring, while quadrilisteroid C (3) featured a surprising 6/6/6/5/5-fused carbocyclic skeleton. Quadrilisteroid C (3) exhibited potent inhibitory activity against LPS-induced proliferation of B lymphocyte cells with an IC50 value of 1.03 μM. Compound 4, demonstrated inhibitory activity against Con A-induced proliferation of T lymphocyte cells with IC50 values of 6.42 μM.

Minor ergosteroids and a 19-nor labdane-type diterpenoid with anti-inflammatory effects from Ganoderma lucidum

A chemical investigation on the fruiting bodies of Ganoderma lucidum led to the isolation and identification of five undescribed ergosteroids including two des-D-steroids (3 and 4) and one rare 6/6/7/5-fused carbon skeletal ergosterol (5) along with one 19-nor labdane-type diterpenoid (6). Their structures including their absolute configurations, were assigned by spectroscopic methods, ECD calculations, and X-ray diffraction analysis. In addition, the anti-inflammatory activities of all the isolates were evaluated. The results indicated that compound 1 can significantly down-regulate the protein expression of iNOS and COX-2 at 20 μM in LPS- stimulated RAW264.7 cells.

Penicimides A and B, two novel diels-alder [4 + 2] cycloaddition ergosteroids from Penicillium herquei

Two novel naturally occurring [4 + 2] Diels-Alder cycloaddition ergosteroids (1 and 2), three undescribed oxidized ergosteroids (3-5), and eleven known analogs (6-16) were isolated from Penicillium herquei. Compounds 1 and 2 represent the first reported cycloadducts of a steroid with 1,4,6-trimethyl-1,6-dihydropyridine-2,5-dione or 4,6-dimethyl-1,6-dihydropyridine-2,5-dione to date. Compound 3 is the C-15 epimer of (22E,24R)-9α,11β-dihydroxyergosta-4,6,8(14),22-tetraen-3-one (14). The chemical structures of these compounds were elucidated through widespread spectroscopic analyses, mainly including HRESIMS and 1D and 2D NMR data, calculated 13C NMR-DP4+ analysis, and electronic circular dichroism (ECD) data analyses. Biological evaluations of Compounds 1-16 revealed that 3, 9-11, and 15 inhibited the production of NO in LPS-induced RAW264.7 cells with an IC50 value from 7.37 ± 0.69 to 38.9 ± 2.25 μM (the positive control dexamethasone IC50: 9.54 ± 0.71 μM). In addition, Compound 3 exhibited a potent inhibitory effect on the secretion of the proinflammatory cytokines TNF-α and IL-6, the transcription level of the proinflammatory macrophage markers TNF-α, and the expression of the iNOS protein.

Neurotrophic Natural Products

Neurotrophins (NGF, BDNF, NT3, NT4) can decrease cell death, induce differentiation, as well as sustain the structure and function of neurons, which make them promising therapeutic agents for the treatment of neurodegenerative disorders. However, neurotrophins have not been very effective in clinical trials mostly because they cannot pass through the blood-brain barrier owing to being high-molecular-weight proteins. Thus, neurotrophin-mimic small molecules, which stimulate the synthesis of endogenous neurotrophins or enhance neurotrophic actions, may serve as promising alternatives to neurotrophins. Small-molecular-weight natural products, which have been used in dietary functional foods or in traditional medicines over the course of human history, have a great potential for the development of new therapeutic agents against neurodegenerative diseases such as Alzheimer's disease. In this contribution, a variety of natural products possessing neurotrophic properties such as neurogenesis, neurite outgrowth promotion (neuritogenesis), and neuroprotection are described, and a focus is made on the chemistry and biology of several neurotrophic natural products.

Nine undescribed oxidized ergosterols from the endophytic fungus Penicillium herquei and their cytotoxic activity

A chemical investigation of the EtOAc extract of the endophytic fungus Penicillium herquei led to the isolation of nine undescribed oxidized ergosterols, penicisterols A-I (1-9), along with ten known analogs (10-19). Their structures and absolute configurations were elucidated by a combination of spectroscopic data analysis, quantum-chemical electronic circular dichroism (ECD) calculations and comparisons, [Rh₂(OCOCF₃)₄]-induced ECD experiments, DFT-calculated ¹³C chemical shifts and DP4+ probability analysis. Compound 1 was a rare example of ergosterol in which the bond between C-8 and C-9 is cleaved to form an enol ether. Moreover, compound 2 possessed a rare (2,5-dioxo-4-imidazolidinyl)-carbamic acid ester group substituted at C-3. All undescribed oxidized ergosterols (1-9) were evaluated for their cytotoxic activity against five cancer cell lines including 4T1 (mouse breast carcinoma), A549 (human pulmonary carcinoma), HCT-116 (human colorectal carcinoma), HeLa (human cervical carcinoma) and Hepg2 (human hepatoma carcinoma) cells. Compounds 2 and 3 displayed moderate cytotoxic activity against 4T1, A549 and HeLa cells, with IC₅₀ values ranging from 17.22 to 31.35 μM.

Guaiazulene and related compounds: A review of current perspective on biomedical applications

BACKGROUND

Thousands of people worldwide pass away yearly due to neurological disorders, cardiovascular illnesses, cancer, metabolic disorders, and microbial infections. Additionally, a sizable population has also been impacted by hepatotoxicity, ulcers, gastroesophageal reflux disease, and breast fissure. These ailments are likewise steadily increasing along with the increase in life expectancy. Finding innovative therapies to cure and consequently lessen the impact of these ailments is, therefore, a global concern.

METHODS AND MATERIALS

All provided literature on Guaiazulene (GA) and its related compounds were searched using various electronic databases such as PubMed, Google Scholar, Web of Science, Elsevier, Springer, ACS, CNKI, and books via the keywords Guaiazulene, Matricaria chamomilla, GA-related compounds, and Guaiazulene analogous.

RESULTS

The FDA has approved the bicyclic sesquiterpene GA, commonly referred to as azulon or 1,4-dimethyl-7-isopropylazulene, as a component in cosmetic colorants. The pleiotropic health advantages of GA and related substances, especially their antioxidant and anti-inflammatory effects, attracted a lot of research. Numerous studies have found that GA can help to manage various conditions, including bacterial infections, tumors, immunomodulation, expectorants, diuretics, diaphoresis, ulcers, dermatitis, proliferation, and gastritis. These conditions all involve lipid peroxidation and inflammatory response. In this review, we have covered the biomedical applications of GA. Moreover, we also emphasize the therapeutic potential of guaiazulene derivatives in pre-clinical and clinical settings, along with their underlying mechanism(s).

CONCLUSION

GA and its related compounds exhibit therapeutic potential in several diseases. Still, it is necessary to investigate their potential in animal models for various other ailments and establish their safety profile. They might be a good candidate to advance to clinical trials.

Ganoaustralins A and B, Unusual Aromatic Triterpenes from the Mushroom Ganoderma australe

Two triterpenes, ganoaustralins A (1) and B (2), featuring unprecedented 6/6/6/5/6 scaffolds were isolated from the fruiting bodies of the mushroom Ganoderma australe. The structures were determined by extensive NMR and HRESIMS spectroscopic analysis. The absolute configuration of the C-25 in ganoaustralin A was assigned by the phenylglycine methyl ester (PGME) method. The relative and absolute configurations of the polycyclic backbones were determined by NMR and ECD calculations, respectively. The plausible biosynthetic pathways of ganoaustralins A and B were proposed. Ganoaustralin B showed weak inhibition against β-secretase 1.

Alkaloids, sesquiterpenoids and hybrids of terpenoid with p-hydroxycinnamic acid from Ganoderma sinensis and their biological evaluation

The fruiting bodies of Ganoderma sinensis are used as food raw materials of marketed healthcare products. To gain an insight into the chemical and biological profling of G. sinensis, twenty-five compounds including eleven undescribed ones (ganodermasines A‒K) and fourteen known ones were isolated. Among them, ganodermasines A‒D are undescribed diketopiperazine alkaloids, ganodermasines E and F are alkaloids containing a pyridine. The structures of undescribed compounds were identified by spectroscopic, computational, and crystallographic methods. The results of acetylcholinesterase (AchE) inhibitory activity show that ganodermasines I and J could inhibit AchE with IC₅₀ values of 26.05 and 20.40 μM, respectively. In addition, neurotrophic assay in PC-12 cells showed that (+)-ganodermasine E, (-)-ganodermasine E, and ganodermasine I could stimulate neurite outgrowth at 10 μM, while the other isolates are inactive. The present findings will lend a hand for further utilization of G. sinensis.

30-norlanostane triterpenoids and steroid derivatives from the endophytic fungus Aspergillus nidulans

Two undescribed 30-norlanostane triterpenoids, named nidulanoids A and B, one ergostane-type steroid with an unusual double bond between C-17 and C-20 designated (17E,22E,24R)-3β,5α-dihydroxyergosta-7,17,22-trien-6,16-dione, and one pregnane, (7Z,9Z,17Z)-,2α,3β-dihydroxypregna-7,9,17 (20)-trien-18-al, along with six known steroids were isolated from the extract of the fungus Aspergillus nidulans. Among them, nidulanosides A and B represents the first example of naturally occurred 30-norlanostane triterpenoids featuring a C9 side-chain moiety at C-17 and a hemiacetal system formed between C-3 and C-19, as an intermediate between lanostane and the regular steriods; the structure of (17E,22E,24R)-3β,5α-dihydroxyergosta-7,17,22-trien-6,16-dione possesses an untypical Δ17,20 double bond; meanwhile, (7Z,9Z,17Z)-,2α,3β-dihydroxypregna-7,9,17 (20)-trien-18-al represents the first example of C-21 steroid with an aldehyde group at C-13. Their structures and absolute stereochemistry were elucidated based on spectroscopic data, electronic circular dichroism (ECD) calculations, and single-crystal X-ray diffraction analysis. (7Z,9Z,17Z)-,2α,3β-dihydroxypregna-7,9,17 (20)-trien-18-al showed moderate inhibitory activities against rat brain cancer (PC12) cell lines, with IC50 value of 7.34 μM. This study enriches the diversified structures of triterpenoids and steroids analogues from A. nidulans and indicated (7Z,9Z,17Z)-,2α,3β-dihydroxypregna-7,9,17(20)-trien-18-al to be a promising lead compound against PC12 cell lines.

An unprecedented ergostane with a 6/6/5 tricyclic 13(14 → 8)abeo-8,14-seco skeleton from Talaromyces adpressus

Talasterone A (1), an unprecedented 6/6/5 tricyclic 13(14 → 8)abeo-8,14-seco-ergostane steroid, together with two known congeners dankasterone B (2) and (14β,22E)-9,14-dihydroxyergosta-4,7,22-triene-3,6-dione (3), were characterized from Talaromyces adpressus. The structure of 1 with absolute configuration was elucidated based on NMR spectroscopic data and ECD calculation. Compound 2 belongs to a class of unconventional 13(14 → 8)abeo-ergostanes, which have been renewed via the 1,2-migration of C-13-C-14 bond to C-8. In addition, compound 1 represents the first example of ergostane with a tricyclic 13(14 → 8)abeo-8,14-seco-ergostane skeleton. The proposed biosynthetic pathway was established with the support of the coisolation of the known congeners from the producing organism. It is especially noteworthy that compound 1 exhibited potent anti-inflammatory activity with an IC₅₀ value of 8.73 ± 0.66 μM, inhibiting the NF-κB pathway and thus reducing the production of proinflammatory cytokines.

Structure and Biological Activity of Ergostane-Type Steroids from Fungi

Mushrooms are known not only for their taste but also for beneficial effects on health attributed to plethora of constituents. All mushrooms belong to the kingdom of fungi, which also includes yeasts and molds. Each year, hundreds of new metabolites of the main fungal sterol, ergosterol, are isolated from fungal sources. As a rule, further testing is carried out for their biological effects, and many of the isolated compounds exhibit one or another activity. This study aims to review recent literature (mainly over the past 10 years, selected older works are discussed for consistency purposes) on the structures and bioactivities of fungal metabolites of ergosterol. The review is not exhaustive in its coverage of structures found in fungi. Rather, it focuses solely on discussing compounds that have shown some biological activity with potential pharmacological utility.

Aspersteroids A-C, Three Rearranged Ergostane-type Steroids from Aspergillus ustus NRRL 275

Aspersteroid A (1), a highly rearranged 1(10 → 6)-abeo-18,22-cyclosterol, together with two new 18,22-cyclosterols (2 and 3), was isolated from the culture extract of Aspergillus ustus NRRL 275. Their structures were determined by spectroscopic analysis, X-ray diffraction, modified Mosher's method, and Rh2(OCOCF3)4-induced electronic circular dichroism experiments. Compound 1 represents a new carbon skeleton with an uncommon 6/6/6/5/5 ring system, which is presumably biosynthesized from A-ring scission, double 1,2-shifts, and C-18/C-22 cyclization. Compound 1 exhibited potent immunosuppressive and antimicrobial activities.

Five undescribed steroids from Talaromyces stipitatus and their cytotoxic activities against hepatoma cell lines

Five undescribed sterol derivatives, (22E,24R)-7α-methoxy-5α,6α-epoxyergosta-8(14),22-diene-3β,15β-diol, (22E,24R)-5α,6α-epoxyergosta-8(14),22-diene-3β,7β,15α-triol, (22E,24R)-3β,5α-dihydroxy-14β,15β-epoxyergosta-7,22-diene-6-one, (22E,24R)-6α-methoxy-7α,15β-dihydroxyergosta-4,8(14),22-triene-3-one, and (25S)-ergosta-7,24(28)-diene-3β,4α,6α,26-tetraol were isolated from the extract of Talaromyces stipitatus, along with eight known congeners. This is the first example of a class of ergosterols isolated from T. stipitatus. Their structures with absolute configurations were elucidated based on NMR spectroscopic data, ECD calculations, and X-ray crystallographic analyses. All these compounds were tested for their effects on three hepatoma cell lines including Hep3B, HepG2, and Huh-7. Moreover, (22E,24R)-5α,6α-epoxyergosta-8(14),22-diene-3β,7β,15α-triol and (22E,24R)-9α,15α-dihydroxyergosta-4,6,8(14),22-tetraen-3-one were further evaluated for their impacts on cell cycle progression and apoptosis due to their pronounced cytotoxicity, to uncover their underlying mechanisms. Our results suggested that their antiproliferative activities were mainly mediated by inducing cell apoptosis.

In vitro and in vivo biological activities of azulene derivatives with potential applications in medicine

Azulene is an aromatic hydrocarbon that possesses a unique chemical structure and interesting biological properties. Azulene derivatives, including guaiazulene or chamazulene, occur in nature as components of many plants and mushrooms, such as Matricaria chamomilla, Artemisia absinthium, Achillea millefolium, and Lactarius indigo. Due to physicochemical properties, azulene and its derivatives have found many potential applications in technology, especially in optoelectronic devices. In medicine, the ingredients of these plants have been widely used for hundreds of years in antiallergic, antibacterial, and anti-inflammatory therapies. Herein, the applications of azulene, its derivatives and their conjugates with biologically active compounds are presented. The potential use of these compounds concerns various areas of medicine, including anti-inflammatory with peptic ulcers, antineoplastic with leukemia, antidiabetes, antiretroviral with HIV-1, antimicrobial, including antimicrobial photodynamic therapy, and antifungal.

Isolation of benzolactones, Ganodumones A-F from Ganoderma lucidum and their antibacterial activities

Six previously undescribed benzolactone constituents, ganodumones A-F (1-6), a new type of Ganoderma meroterpenoids (GMs) fused with 1,2,3,4,5-pentasubstituted phenyl and 1',2'-dioxy-3'-methyl-pentyl chain were isolated from the fruiting bodies of Ganoderma lucidum. Their structures were determined by spectroscopic analysis, X-ray crystal diffraction, and ECD computational methods. Meanwhile, bioactive evaluation showed that compounds 3 and 5 have antibacterial activities against Microsporum gypseum with MIC₉₀ 56.86 ± 3.98 and 18.48 ± 0.47 μg/mL, respectively.

NMR-based Structural Classification, Identification, and Quantification of Triterpenoids from Edible Mushroom Ganoderma resinaceum

Ganoderma mushrooms have been widely used as functional food in China, Japan, and Korea. Ganoderma triterpenoids are deemed to be the main functional constituents. The structures of Ganoderma triterpenoids are complex but quite similar, which makes their analyses markedly limited. In this study, we developed a general 2D NMR method to differentiate Ganoderma triterpenoids, which classifies them into six types (A-F). Then, by the NMR-based isolation of A-F type triterpenoids from the fruiting bodies of G. resinaceum, four new compounds (1-4) and eight known compounds (5-12) were obtained. Moreover, combined with spiking experiments in 1D and 2D NMR spectra, compounds 5, 7, and 8, which belong to triterpenoids of A and B types, were identified. At the end, to achieve a more extensive application for this NMR method, a qNMR method for the absolute quantification of 5, 7, and 8 in the gross triterpenoids from G. resinaceum was set up. The results showed that this NMR method is reliable for the NMR-guided isolation and quantification of triterpenoids in G. resinaceum.

C28 steroids from the fruiting bodies of Ganoderma resinaceum with potential anti-inflammatory activity

Eight undescribed ergostane-type steroids, (22E,24R)-ergosta-7,22-dien-3β,5α-diol- 6,5-olide, (22E,24R)-ergosta-7,9(11),22-trien-3β,5β,6β-triol, (22E,24R)-6β-methoxy ergosta-7,9(11),22-trien-3β,5α,14β-triol, (22E,24R)-9α,15α-dihydroxyergosta-4,6,8 (14),22-tetraen-3-one, (22E,24R)-ergosta-5,8,22-trien-3β,11α-dihydroxyl-7-one, (22E,24R)-ergosta-4,7,22-trien-3β,9α,14β-trihydroxyl-6-one, (22E,24R)-ergosta-7,22- dien-3β,9α,14β-trihydroxyl-6-one, and (22E,24R)-6β-methoxyergosta-7,22-dien-3β, 5α,9α,14β-tetraol, and twenty-one known analogues were isolated from the fruiting bodies of Ganoderma resinaceum Boud. Their chemical structures were determined on the basis of comprehensive spectroscopic analysis and X-ray crystal diffraction, as well as empirical pyridine-induced deshielding effects. Furthermore, selected compounds were evaluated for their inhibitory effects on macrophage activation using an inhibition of nitric oxide production assay. Finally, (22E,24R)-ergosta-5,8,22- trien-3β,11α-dihydroxyl-7-one, (22E,24R)-ergosta-4,7,22-trien-3β,9α,14β-tri hydroxyl-6-one, (22E,24R)-6β-methoxyergosta-7,22-dien-3β,5α,9α,14β-tetraol, (22E,24R)-ergosta-6,9,22-trien-3β,5α,8α-triol,ergost-6,22-dien-3β,5α,8α-triol, 5α,6α-epoxy-(22E,24R)-ergosta-8,22-diene-3β,7α-diol, 5α,6α-epoxy-(22E,24R)- ergosta-8(14),22-diene-3β,7α-diol, 5α,6α-epoxy-(22E,24R)-ergosta-8(14),22-diene-3β, 7β-diol, and 22E-7α-methoxy-5α,6α-epoxyergosta-8(14),22-dien-3β-ol showed inhibitory effects on NO production with IC₅₀ values ranging from 3.24 ± 0.02 to 35.19 ± 0.41 μM compared with L-NMMA (IC₅₀ 49.86 ± 2.13 μM), indicating that they have potential anti-inflammatory activity.

New Unsaturated Lactones and a Meroterpenoid from Ganoderma lucidum

From the dried fruiting bodies of Ganoderma lucidum, 2 new unsaturated lactones, dayaolingzhilactones A and B (1 and 2), and 1 new meroterpenoid, dayaolingzhiol H (3), together with 10 known compounds (4-13), were isolated. Their chemical structures were identified by using spectroscopic data and calculated specific rotation. The inhibitory activities of compounds 1 and 2 toward acetylcholinesterase (AchE) were assessed in vitro with tacrine as the positive control. Both of them exhibited moderate AchE inhibitory activities at the concentration of 50 μM.

Rearranged ergostane-type natural products: chemistry, biology, and medicinal aspects

Rearranged ergostane-type natural products are structurally intriguing and exhibit biologically relevant properties.

Unusual constituents from the medicinal mushroom Ganoderma lingzhi

Extensive studies have revealed that triterpenoids, meroterpenoids, and polysaccharides are the main constituents of the well-known traditional Chinese medicinal mushroom Ganoderma. In this study, we report seven previously undescribed sesquiterpenoids, including six gymnomitranes (1–6) and a novel type of sesquiterpenoid (8), together with a polyketide (7) and a known steroid (9) from the fruiting bodies of Ganoderma lingzhi, a fungus used as traditional medicine and food supplement in East Asia for ages. The structures of 1–8 were deduced by analysis of spectroscopic data, X-ray single crystal diffractions and TDDFT/ECD calculations. Compound 8 possessed an unusual 14(7→6)-cuparane scaffold. Compound 9 exhibited weak cytotoxicity against the five human cancer cell lines HL-60, MCF-7, SW480, A549, and SMMC-7721 with IC₅₀ values of 18.0–32.3 μM. A simple structure-activity-relationship (SAR) investigation by acetylating the 5-OH of 9 (9a) suggested that the 5-OH is essential for its cytotoxicity. Additionally, the biosynthetic pathways for compounds 2 and 8 are discussed.

Extensive studies have revealed that triterpenoids, meroterpenoids, and polysaccharides are the main constituents of the well-known traditional Chinese medicinal mushroom Ganoderma.

Two new bioactive steroids from a mangrove-derived fungus Aspergillus sp

Two unusual naturally Diels-Alder additive steroids, ergosterdiacids A and B (1 and 2), constructing a 6/6/6/6/5 pentacyclic steroidal system, together with three known compounds (3-5) were obtained from the mangrove-derived fungus Aspergillus sp. Their structures were elucidated based on the comprehensive spectroscopic analysis, including 1D, 2D NMR and HRESIMS, as well as the quantum chemical ECD calculations. The plausible biosynthetic pathways of 1 and 2 were discussed. In the bioactivity assays, 1 and 2 exhibited potential in vitro inhibition activity against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with an IC₅₀ value of 15.1 and 30.1 μM, respectively. The inhibitory kinetic experiments indicated that both of them acted via a noncompetitive inhibition mechanism. Moreover, 1 and 2 showed strong in vitro anti-inflammatory effects by suppressing the NO production at 4.5 and 3.6 μM, respectively.

Survey of natural products reported by Asian research groups in 2017

The new natural products reported in 2017 in peer-reviewed articles in journals with good reputations were reviewed and analyzed. The advances made by Asian research groups in the field of natural products chemistry in 2017 were summarized. Compounds with unique structural features and/or promising bioactivities originating from Asian natural sources were discussed based on their structural classification.

Hot off the press

A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as furanmonogone A from Hypericum monogynum.

(±)-Applanatumines B–D: novel dimeric meroterpenoids from Ganoderma applanatum as inhibitors of JAK3

Applanatumines B–D (1–3), three pairs of dimeric meroterpenoid enantiomers featuring the presence of a 6-oxo-4,4a,5,5a,6,8,8a,8b-octahydrofuro[3′,4′:4,5]cyclopenta[1,2-b]pyran-3-carbaldehyde structure core, were isolated from the fruiting bodies of Ganoderma applanatum.