Five new (1–5) and two known xanthones (6 and 7), one of the latter (6) obtained for the first time as a natural product, together with three known anthraquinones, questin, penipurdin A, and questinol, were isolated from the coastal saline soil-derived Aspergillus iizukae by application of an OSMAC (one strain many compounds) approach. Their structures were determined by interpretation of nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS) data, as well as comparison of these data with those of related known compounds. Antiviral activity of xanthones 1−7 was evaluated through the cytopathic effect (CPE) inhibition assay, and compound 2 exhibited distinctly strong activity towards influenza virus (H1N1), herpes simplex virus types 1 (HSV-1) and 2 (HSV-2) with IC50 values of 44.6, 21.4, and 76.7 μM, respectively, which indicated that it was worth to further investigate it as a potential lead compound. The preliminary structure-activity relationship of the xanthones is discussed.
21 September 2024 in Journal of Colloid and Interface Science
Three new γ-hydroxyl butenolides (1–3), a pair of new enantiomeric spiro-butenolides (4a and 4b), a pair of enantiomeric cyclopentenones (5a new and 5b new natural), and six known compounds (6–11), were isolated from Aspergillus sclerotiorum. Their structures were established by spectroscopic data and electronic circular dichroism (ECD) spectra. Two pairs of enantiomers [(+)/(–)-6c and (+)/(–)-6d] obtained from the reaction of 6 with acetyl chloride (AcCl) confirmed that 6 was a mixture of two pairs of enantiomers. In addition, the X-ray data confirmed that 7 was also a racemate. The new metabolites (1−5) were evaluated for their inhibitory activity against cancer and non-cancer cell lines. As a result, compound 1 exhibited moderate cytotoxicity to HL60 and A549 with IC50 values of 6.5 and 8.9 µM, respectively, and weak potency to HL-7702 with IC50 values of 17.6 µM. Furthermore, compounds 1−9 were screened for their antimicrobial activity using the micro-broth dilution method. MIC values of 200 μg/mL were obtained for compounds 2 and 3 towards Staphylococcus aureus and Escherichia coli, while compound 8 exhibited a MIC of 50 μ/mL towards Candida albicans.
Five new pyran rings containing polyketides, penicipyrans A–E (1–5), together with the known pestapyrone A (6), were isolated from the saline soil-derived Penicillium raistrickii. Their structures were determined by interpretation of NMR and HRESIMS data. The absolute configurations of compounds 4 and 5 were established by the modified Mosher’s method and single-crystal X-ray diffraction analysis, respectively. These compounds possessed high structural diversity including two α-pyrones (1, 2), three isocoumarins (3, 4, 6), and one dihydropyran derivative (5). Among them, Compound 5 exhibited cytotoxicity against HL-60 and K562 cell lines with IC50 values of 4.4 and 8.5 μM, respectively.
Three new diastereomers of polyketides (PKs), raistrickiones A−C (1–3), together with two new analogues, raistrickiones D and E (4 and 5), were isolated from a highly productive strain of Penicillium raistrickii, which was subjected to an experimental thermo-change strategy to tap its potential of producing new secondary metabolites. Metabolites 1 and 2 existed in a diastereomeric mixture in the crystal packing according to the X-ray data, and were laboriously separated by semi-preparative HPLC on a chiral column. The structures of 1–5 were determined on the basis of the detailed analyses of the spectroscopic data (UV, IR, HRESIMS, 1D, and 2D NMR), single-crystal X-ray diffractions, and comparison of the experimental and calculated electronic circular dichroism spectra. Compounds 1–5 represented the first case of 3,5-dihydroxy-4-methylbenzoyl derivatives of natural products. Compounds 1–5 exhibited moderate radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH).
12 February 2024 in Frontiers in Bioengineering and Biotechnology
The mitochondria act as the main producers of reactive oxygen species (ROS) within cells. Elevated levels of ROS can activate the mitochondrial apoptotic pathway, leading to cell apoptosis. In this study, we devised a molecular prodrug named CTT2P, demonstrating notable efficacy in facilitating mitochondrial apoptosis. To develop nanomedicine, we enveloped CTT2P within bovine serum albumin (BSA), resulting in the formulation known as CTT2P@B. The molecular prodrug CTT2P is achieved by covalently conjugating mitochondrial targeting triphenylphosphine (PPh3), photosensitizer TPPOH2, ROS-sensitive thioketal (TK), and chemotherapeutic drug camptothecin (CPT). The prodrug, which is chemically bonded, prevents the escape of drugs while they circulate throughout the body, guaranteeing the coordinated dispersion of both medications inside the organism. Additionally, the concurrent integration of targeted photodynamic therapy and cascade chemotherapy synergistically enhances the therapeutic efficacy of pharmaceutical agents. Experimental results indicated that the covalently attached prodrug significantly mitigated CPT cytotoxicity under dark conditions. In contrast, TPPOH2, CTT2, CTT2P, and CTT2P@B nanoparticles exhibited increasing tumor cell-killing effects and suppressed tumor growth when exposed to light at 660 nm with an intensity of 280 mW cm−2. Consequently, this laser-triggered, mitochondria-targeted, combined photodynamic therapy and chemotherapy nano drug delivery system, adept at efficiently promoting mitochondrial apoptosis, presents a promising and innovative approach to cancer treatment.