Isolation and stereospecific synthesis of indole alkaloids with lipid-lowering effects from the marine-derived fungus Colletotrichum gloeosporioides BB4.

Seven undescribed compounds, colletotrichindoles A-E, colletotrichaniline A, and colletotrichdiol A, as well as three known compounds, (-)-isoalternatine A, (+)-alternatine A and 3-hydroxybutan-2-yl 2-phenylacetate were isolated from the marine-derived fungus Colletotrichu gloeosporioides BB4. The racemic mixtures colletotrichindole A，colletotrichindole C, and colletotrichdiol A were further separated by chiral chromatography to give three pairs of enantiomers (10S,11R,13S)/(10R,11S,13R)-colletotrichindole A, (10R,11R,13S)/(10S,11S,13R)-colletotrichindole C, and (9S,10S)/(9R,10R)-colletotrichdiol A, respectively. The chemical structures of seven undescribed compounds and the known compounds, (-)-isoalternatine A, and (+)-alternatine A were determined using a combination of NMR, MS, X-ray diffraction, ECD calculations, and/or chemical synthesis. All possible enantiomers of colletotrichindoles A-E were synthesized and used to determine the absolute configurations of the natural products by comparing their spectroscopic data and HPLC retention times on a chiral column. In addition, the X-ray crystal structures of the known compounds (-)-isoalternatine A and (+)-alternatine A were also obtained to confirm their absolute configurations. (10S,11R,13S)-Colletotrichindole A, colletotrichindole B, and (+)-alternatine A significantly reduced triglyceride levels in 3T3-L1 cells with EC50 values of 5.8, 9.0, and 1.3 µM, respectively.

Lentinuses A-B, two alkaloids from the marine-derived fungus Lentinus sajor-caju with potent anti-pulmonary fibrosis activity.

By adding natural amino acids into the medium as sole nitrogen source, twenty-four compounds, including two new alkaloids lentinuses A-B (1-2) with a rare oxazinone core in marine natural products, one new natural product 3-acetamido-4-phenylfurazan (3), 9ß-ergosterol (22) were firstly discovered from a marine fungus, and twenty known compounds (4-21, 23-24) were isolated from the marine-derived fungus Lentinus sajor-caju. The chemical structures of all these compounds were elucidated by HRMS, NMR spectroscopy and X-ray diffraction. Compounds 1-24 were evaluated for their inhibitory activity against TGF-ß1-induced collagen accumulation in human fetal lung fibroblasts (HFL1). Compounds 2, 3, 12, 22, and 23 showed potent activity against TGF-ß1-induced collagen accumulation and low toxicity to HFL1 cells. The binding mode of lentinus B (2) with TGF-ß1 receptor was then performed by using Schrödinger software, and the result showed that lentinus B possesses a strong binding force such as hydrogen bonding and hydrophobic interactions to the protein, which may provide a theoretical basis to design more potent anti-fibrotic drugs in the future.

ß-Carboline Alkaloids From the Deep-Sea Fungus Trichoderma sp. MCCC 3A01244 as a New Type of Anti-pulmonary Fibrosis Agent That Inhibits TGF-ß/Smad Signaling Pathway.

Pulmonary fibrosis is a scarring disease of lung tissue, which seriously threatens human health. Treatment options are currently limited, and effective strategies are still lacking. In the present study, 25 compounds were isolated from the deep-sea fungus Trichoderma sp. MCCC 3A01244. Among them, two ß-carboline alkaloids, trichocarbolines A (1) and C (4) are new compounds. The chemical structures of these compounds were elucidated based on their HRESIMS, 1D and 2D NMR spectra, optical rotation calculation, and comparisons with data reported in the literature. Trichocarboline B [(+)- and (-)-enantiomers] had previously been synthesized, and this is its first report as a natural product. Their anti-pulmonary fibrosis (PF) activity and cytotoxicity were investigated. Compounds 1, 11, and 13 strongly inhibited TGF-ß1-induced total collagen accumulation and showed low cytotoxicity against the HFL1 cell line. Further studies revealed compound 1 inhibited extracellular matrix (ECM) deposition by downregulating the expression of protein fibronectin (FN), proliferating cell nuclear antigen (PCNA), and α-smooth muscle actin (α-SMA). Mechanistic study revealed that compound 1 decreased pulmonary fibrosis by inhibiting the TGF-ß/Smad signaling pathway. As a newly identified ß-carboline alkaloid, compound 1 may be used as a lead compound for developing more efficient anti-pulmonary fibrosis agents.

Exophilone, a Tetrahydrocarbazol-1-one Analogue with Anti-Pulmonary Fibrosis Activity from the Deep-Sea Fungus Exophiala oligosperma MCCC 3A01264.

A new compound, exophilone (1), together with nine known compounds (2-10), were isolated from a deep-sea-derived fungus, Exophiala oligosperma. Their chemical structures, including the absolute configuration of 1, were elucidated using nuclear magnetic resonance (NMR) spectroscopy, high-resolution electrospray ionization mass spectroscopy (HRESIMS), and electronic circular dichroism (ECD) calculation. Compounds were preliminarily screened for their ability to inhibit collagen accumulation. Compounds 1, 4, and 7 showed weaker inhibition of TGF-ß1-induced total collagen accumulation in compared with pirfenidone (73.14% inhibition rate). However, pirfenidone exhibited cytotoxicity (77.57% survival rate), while compounds 1, 4, and 7 showed low cytotoxicity against the HFL1 cell line. Particularly, exophilone (1) showed moderate collagen deposition inhibition effect (60.44% inhibition rate) and low toxicity in HFL1 cells (98.14% survival rate) at a concentration of 10 µM. A molecular docking study suggests that exophilone (1) binds to both TGF-ß1 and its receptor through hydrogen bonding interactions. Thus, exophilone (1) was identified as a promising anti-pulmonary fibrosis agent. It has the potential to be developed as a drug candidate for pulmonary fibrosis.

Biotransformations of anthranilic acid and phthalimide to potent antihyperlipidemic alkaloids by the marine-derived fungus Scedosporium apiospermum F41-1.

A new diphenylamine derivative, scediphenylamine A (1), together with six phthalimide derivatives (2-7) and ten other known compounds (8-17) were obtained from the marine-derived fungus Scedosporium apiospermum F41-1 fed with synthetically prepared anthranilic acid and phthalimide. The structure and absolute configuration of the new compound were determined by HRMS, NMR, and X-ray crystallography. Evaluation of their lipid-lowering effect in 3T3-L1 adipocytes showed that scediphenylamine A (1), N-phthaloyl-tryptophan-methyl ester (4), 5-(1,3-dioxoisoindolin-2-yl) pentanamide (5), perlolyrine (10) and flazine (11) significantly reduced triglyceride level in 3T3-L1 cells by inhibiting adipogenic differentiation and synthesis with the EC50 values of 4.39, 2.79, 3.76, 0.09, and 4.52 µM, respectively. Among them, perlolyrine (10) showed the most potent activity, making it a candidate for further development as a potential agent to treat hyperlipidemia.

[Effect of Huangqi San on AMPK/ACC/CPT1 pathway in hyperlipidemia rats].

To investigate the mechanism of the treatment of hyperlipidemia rats induced by Huangqi San. The 40 male SD rats were randomly divided into normal group, model group, Huangqi San low and high dose group (1, 2 g·kg⁻¹), and positive lipitor group (2 mg·kg⁻¹). The normal group feeds on base feed, and other groups feed on high-fat feed. After 8 weeks, the hyperlipidemia model was successful. After intervention by drugs for 13 weeks, fasting blood glucose, total cholesterol, triglycerides and LDL cholesterol content of all rats were measured. The pathological changes of liver and skeletal muscle of rats were observed in rats. Real-time PCR and Western blot were used to detect the mRNA and protein expression levels of AMPK signaling pathway in the liver and skeletal muscles (AMPK, ACC, CPT1A, SREBP2, HMGCR). The degree of FPG, TC, TG and LDL-C were the highest in the model group, and the liver and skeletal muscle pathology were the most obvious. After intervention by Huangqi San and lipitor, a significant reduction in the blood sugar blood fat, liver, and skeletal muscle injury has improved significantly, except SREBF2 and HMGCR mRNA and protein expression of this enzyme is reduced, other AMPK pathway related mRNA and protein expression increased significantly. Huangqi San effect is superior to lipitor. Huangqi San may improve hyperlipidemia by regulating the AMPK signaling pathway, increasing the oxidation of fatty acids and inhibiting cholesterol synthesis.