Insights into Ganoderma fungi meroterpenoids opening a new era of racemic natural products in mushrooms.

Ganoderma meroterpenoids (GMs) containing 688 structures to date were discovered to have multiple remarkable biological activities. 65.6% of meroterpenoids featuring stereogenic centers from Ganoderma species are racemates. Further, GMs from different Ganoderma species seem to have their own characteristics. In this review, a comprehensive summarization of GMs since 2000 is presented, including GM structures, structure corrections, biological activities, physicochemical properties, total synthesis, and proposed biosynthetic pathways. Additionally, we especially discuss the racemic nature, species-related structural distribution, and structure-activity relationship of GMs, which will provide a likely in-house database and shed light on future studies on GMs.

Z16b, a natural compound from Ganoderma cochlear is a novel RyR2 stabilizer preventing catecholaminergic polymorphic ventricular tachycardia.

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited, lethal ventricular arrhythmia triggered by catecholamines. Mutations in genes that encode cardiac ryanodine receptor (RyR2) and proteins that regulate RyR2 activity cause enhanced diastolic Ca2+ release (leak) through the RyR2 channels, resulting in CPVT. Current therapies for CPVT are limited. We found that Z16b, a meroterpenoid isolated from Ganoderma cochlear, inhibited Ca2+ spark frequency (CaSF) in R2474S/ + cardiomyocytes in a dose-dependent manner, with an IC50 of 3.2 µM. Z16b also dose-dependently suppressed abnormal post-pacing Ca2+ release events. Intraperitoneal injection (i.p.) of epinephrine and caffeine stimulated sustained ventricular tachycardia in all R2474S/+ mice, while pretreatment with Z16b (0.5 mg/kg, i.p.) prevented ventricular arrhythmia in 9 of 10 mice, and Z16b administration immediately after the onset of VT abolished sVT in 9 of 12 mice. Of translational significance, Z16b significantly inhibited CaSF and abnormal Ca2+ release events in human CPVT iPS-CMs. Mechanistically, Z16b interacts with RyR2, enhancing the "zipping" state of the N-terminal and central domains of RyR2. A molecular docking simulation and point mutation and pulldown assays identified Z16b forms hydrogen bonds with Arg626, His1670, and Gln2126 in RyR2 as a triangle shape that anchors the NTD and CD interaction and thus stabilizes RyR2 in a tight "zipping" conformation. Our findings support that Z16b is a novel RyR2 stabilizer that can prevent CPVT. It may also serve as a lead compound with a new scaffold for the design of safer and more efficient drugs for treating CPVT.

(±)-Gancochlearols J - N, renoprotective meroterpenoids from Ganoderma cochlear.

Five pairs of meroterpenoid enantiomers, (±)-gancochlearols J - N (1-5), were isolated from the fruiting bodies of Ganoderma cochlear. Their structures were elucidated on the basis of 1D and 2D NMR and HRESIMS data. The absolute configurations of gancochlearols J - M (1-4) were assigned by electronic circular dichroism (ECD) calculations. Biological evaluation showed that (-)-1 and (-)-2 could inhibit renal fibrosis in TGF-ß1-induced rat kidney proximal tubular cells (NRK-52e).

Gancochlearols E - I, meroterpenoids from Ganoderma cochlear against COX-2 and triple negative breast cancer cells and the absolute configuration assignment of ganomycin K.

Five new meroterpenoids, gancochlearols E - I (1, 3-6), and one compound ganomycin K (2) were isolated from the fruiting bodies of G. cochlear. Their structures were assigned by 1D and 2D NMR, MS, and CD analysis. Rh2(OCOCF3)4-induced ECD method was used to clarify the absolute configuration of secondary alcohol in 1 and 2. Biochemical evaluation showed that all the isolates significantly inhibit COX-2 enzyme in vitro with the IC50 values range from 1.03 µM to 2.71 µM. Further cellular assay revealed that (+)-3 and (-)-6 could suppress metastatic phenotype of triple-negative breast cancer (TNBC) cells via impeding the epithelial-mesenchymal transition (EMT).

Lucidumones B-H, racemic meroterpenoids that inhibit tumor cell migration from Ganoderma lucidum.

Seven new meroterpenoids, lucidumones B-H (1 and 3-8), along with one known meroterpenoid (2), were isolated from the fruiting bodies of Ganoderma lucidum. The structures of the new compounds were assigned by spectroscopic and computational methods. All the isolated compounds were tested for their inhibition on human cancer cell migration. It was found that compounds (-)-1, (+)-2, (-)-4, (+)-6, and (+)-8 could significantly inhibit cell migration in KYSE30 cell line. Further examination disclosed that cell migration inhibition of (+)-6 and (+)-8 might be related with downregulation of N-cadherin.

Renoprotective ganodermaones A and B with rearranged meroterpenoid carbon skelotons from Ganoderma fungi.

Two structurally novel meroterpenoids, ganodermaones A (1) and B (2), were isolated from Ganoderma fungi (G. cochlear and G. lucidum). The structures of 1 and 2 were assigned by spectroscopic, computational, and X-ray diffraction methods. Compounds 1 and 2 represent the first examples of meroterpenoids in Ganoderma fungal species featuring with carbon migration. The plausible biosynthetic pathway for 1 was proposed. Biological evaluation showed that both 1 and 2 could inhibit renal fibrosis in TGF-ß1-induced kidney proximal tubular cells.

Skeletal meroterpenoids from Ganoderma petchii mushrooms that potentially stimulate umbilical cord mesenchymal stem cells.

(±)-Petchilactones A-C (1-3), three pairs of enantiomeric meroterpenoids respectively with a 6/6/5/5 or a 5/5/5/7/6 ring system were isolated from Ganoderma petchii. Their structures including absolute configurations were assigned by using spectroscopic, computational, and X-ray diffraction methods. Compounds 1 and 2 represent a new skeletal meroterpenoid. Biological evaluation found that (-)-1 and (-)-3 could induce umbilical cord mesenchymal stem cells into keratinocyte-like cells.

(±) Cochlearoids N-P: three pairs of phenolic meroterpenoids from the fungus Ganoderma cochlear and their bioactivities.

Three pairs of meroterpenoids (±) cochlearoids N-P (1-3) were isolated from the fruiting bodies of Ganoderma cochlear. Their structures including absolute configurations were assigned by spectroscopic techniques. All the isolated compounds were tested for their inhibitory activities toward BRD4, human cancer cells, and micro-organisms. The results show that the enantiomers of (±)-1 are BRD4 inhibitors, (-)-1 and (+)-3 are cytotoxic against human cancer cells (K562) with IC50 values of 7.68 and 6.68 µM, respectively. Besides compounds (±)-2 and (±)-3 exhibit potent inhibitory activity against Staphylococcus aureus with IC50 values in the range of 5.43-17.99 µM.

Two New Triterpenoids from the Roots of Codonopsis pilosula.

Pseudolarolides U and V, two new triterpenoids, and four biogenetically related compounds, pseudolarolides E, F, K, and P were isolated from the roots of Codonopsis pilosula (Campanulaceae). Their structures were determined by spectroscopic data. The regulation of Sirtuin 1 (SIRT1) activity by all the isolated compounds was evaluated.

Three New Polyynes from Codonopsis pilosula and Their Activities on Lipid Metabolism.

Three new polyynes, named choushenpilosulynes A-C (1-3), were isolated from an 85% aqueous EtOH extract of the roots of Codonopsis pilosula cultivated in Xundian County of Yunnan province, China. Their structures, including the absolute configuration of the glucose residue in 1 and 2, were determined by spectroscopic analysis and gas chromatography (GC). In addition, biological evaluation shows that all the compounds can inhibit the expression of the squalene monooxygenase (SQLE) gene in HepG2 cells, suggesting that these compounds may be involved in lipid metabolism.

Cytotoxic and N-Acetyltransferase Inhibitory Meroterpenoids from Ganoderma cochlear.

Seven compounds, including two pairs of new meroterpenoids, (+)- and (-)-gancochlearol C (1), (+)- and (-)-cochlearoid Q (3), and a new meroterpenoid gancochlearol D (2), together with four known meroterpenoids were isolated from the aqueous EtOH extract of the fruiting bodies of Ganoderma cochlear. Their structures were determined by spectroscopic data. The isolated compounds were evaluated for their cytotoxic activity against three human lung cancer cells (H1975, PC9, A549) and N-acetyltransferase inhibitory property. The results show that (+)-gancochlearol C could inhibit N-acetyltransferase with an IC50 value of 5.29 µM. In addition, ganomycin F was found to show moderate activity against the H1975 human lung cancer cell line, with an IC50 value of 19.47 µM.

Two Novel Proline-Containing Catechin Glucoside from Water-Soluble Extract of Codonopsis pilosula.

Choushenflavonoids A (1) and B (2), two unusual proline-containing catechin glucosides, were isolated from the roots of Codonopsis pilosula cultivated in a high-altitude location of Yunnan province. Their structures were determined by spectroscopic data and chemical methods. Specifically, the absolute configuration of glucose residue in 1 and 2 was assigned by acid hydrolysis followed by derivatization and gas chromatography (GC) analysis. In addition, biological evaluation of 1 and 2 against Sirtuin 1 (SIRT1) was carried out.

A Novel Flavonoid Glucoside from the Fruits of Lycium ruthenicun.

A novel flavonoid glucoside, ruthenicunoid A (1), together with eight known substances, were isolated from the fruits of Lycium ruthenicun Murr. Their structures were elucidated by extensive spectroscopic data and chemical methods. Especially, the absolute configuration of glucose residue in 1 was assigned by acid hydrolysis followed by derivatization and GC analysis. Biological evaluation towards Sirtuin 1 (SIRT1) found that compounds 1 and 2 exhibit inhibitory activity against SIRT1 in a concentration-dependent manner, indicating its potential on SIRT1-associated disorders.

Meroterpenoid Dimers from Ganoderma Mushrooms and Their Biological Activities Against Triple Negative Breast Cancer Cells.

(±)-Dimercochlearlactones A-J (1-10), ten pairs of novel meroterpenoid dimers and one known spirocochlealactone A (11), were isolated from Ganoderma mushrooms. The structural elucidation of new compounds, including their absolute configurations, depends on spectroscopic analysis and electronic circular dichroism (ECD) calculations. Biological studies showed that (+)- and (-)-2, (-)-3, and (+)- and (-)-11 are cytotoxic toward human triple negative breast cancer (TNBC) cells (MDA-MB-231) with IC50 values of 28.18, 25.65, 11.16, 8.18, and 13.02 µM, respectively. Wound healing assay revealed that five pairs of meroterpenoids (±)-5-(±)-8 and (±)-10 could significantly inhibit cell mobility at 20 µM in MDA-MB-231 cells. The results provide a new insight into the biological role of Ganoderma meroterpenoids in TNBC.

Meroterpenoids containing benzopyran or benzofuran motif from Ganoderma cochlear.

Five undescribed benzopyran containing meroterpenoids, ganodercins Q－U, two undescribed benzofuran containing meroterpenoids, ganodercins V and W, and two known meroterpenoids were isolated from Ganoderma cochlear. Their structures were elucidated by using HRESIMS, NMR spectroscopy and computational methods. The results of biochemical studies using a palmitic acid (PA) induced insulin resistance (IR) model show that (-)-ganodercin Q, (+)-ganodercins R and W activate phospho-AKT (p-AKT) at 20 µM and improve glucose uptake in a concentration dependent manner. The results of renoprotection studies show that (+)-ganodercin S, cochlearol F, (+)- and (-)-ganodercins V reduce the expression of collagen I.

Four new polyynes from Codonopsis pilosula collected in Yunnan province, China.

Choushenpilosulynes D-G (1-4): four new polyynes were isolated from the roots of Codonopsis pilosula (Campanulaceae) cultivated in Yunnan province, China. Their structures were identified by spectroscopic methods. Bioactive evaluation showed that choushenpilosulynes E (2) and F (3) demonstrated potent inhibitory effect on lipid formation induced by 100 µM oleic acid stimulation. In addition, choushenpilosulyne F (3) uncovered inhibitory activity against the expression of human 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) and squalene monooxygenase (SQLE) gene transcript in HepG2 cells.

Meroterpenoids and alkaloids from Ganoderma australe.

Two new mertoterpenoids, australins A (1) and B (2), and a new alkaloid, australine (4), together with five known compounds (3, 5-8) were isolated from the fruiting bodies of Ganoderma australe. Their structures including absolute configurations were assigned by using spectroscopic methods and electronic circular dichroism (ECD) calculations. Racemic australin A was further purified by chiral HPLC. Biological assessments reveal that compounds (+)-1 and 7 could significantly protect SH-SY5Y cells from glutamate-induced neural excitotoxicity.

Terminal Cyclohexane-Type Meroterpenoids from the Fruiting Bodies of Ganoderma cochlear.

Eleven new cyclohexane-type meroterpenoids (1, 3-5, 7, 8, 11-15) and four known similar meroterpenoids (2, 6, 9, and 10) were isolated from Ganoderma cochlear. Their structures and absolute configurations at stereogenic centers were elucidated by using HRESIMS, NMR spectroscopy and computational methods. In addition, the structure of the known meroterpenoid, cochlearol G (2), was revised, and the absolute configurations at the stereogenic centers of known meroterpenoids 9 and 10 were determined. All the isolated meroterpenoids were evaluated for their activities against renal fibrosis and triple negative breast cancer, and their insulin resistance. The results of the renal fibrosis study showed that meroterpenoid 11 inhibits over-expression of fibronectin, collagen I and α-SMA. Results of the wound healing study revealed that 4, 6 and 8 significantly inhibit migration of BT549 cells. Observations made in Western blotting experiments showed that 6 decreases the levels of TWIST1 and ZEB1, and increases the level of E-cadherin. Finally, meroterpenoids 7, 9, 11, and 15 significantly up-regulate p-AMPK protein expression in normal L6 myotubes cells.

(±) Gancochlearols A and B: cytotoxic and COX-2 inhibitory meroterpenoids from Ganoderma cochlear.

(+)- and (-)-gancochlearols A (1) and B (2), two pairs of dimeric mertoterpenoid enantiomers were isolated from the fruiting bodies of Ganoderma cochlear. Their structures were identified by spectroscopic methods. Biological assessments show that the enantiomers of 1 and 2 are cytotoxic against three human cancer cell lines (A549, K562, Huh-7) and could inhibit COX-2 expression with IC50 values less than 10 µM.

Ganoderma cochlear Metabolites as Probes to Identify a COX-2 Active Site and as in Vitro and in Vivo Anti-Inflammatory Agents.

(±)-Dispirocochlearoids A-C (1-3), meroterpenoids with a 6/6/5/6/6/6 ring system, were isolated from Ganoderma cochlear. 1-3 are selective COX-2 inhibitors with an IC50 value of (-)-2 at 386 nM. Site-directed mutagenesis identified His351 as a COX-2 active site. In vivo anti-inflammatory activities of (-)-2 were performed against acute lung injury in mice.