Peniandrastins A-H: Andrastin-type meroterpenoids with immunosuppressive activity from a Penicillium sp

Quinazolinone nitriles and related metabolites from the deep-sea-derived fungus Penicillium viridicatum MCCC 3A00265

Two new quinazolinone nitriles (1 and 2) and one new indole alkaloid (3), together with 13 known compounds, were isolated from the deep-sea-derived Penicillium viridicatum MCCC 3A00265. Their structures were determined by extensive spectroscopic analysis, with the absolute configurations established by comparing experimental and calculated electronic circular dichroism (ECD) and optical rotation (OR) data as well as biogenetic considerations. Viricyanoamides A and B (1 and 2) are the sole representatives of quinazolinones featuring a nitrile group, while solitumidine F (3) incorporates a rare pyrrolidinedione unit as an indole terpenoid. In particular, compounds 2 and 10 exhibit significant activity in reactivating mutant p53 at 10 μM, indicating their potential for application in cancer therapy.

DMOA-derived polycyclic meroterpenoids with antiviral activities from the deep-sea-derived fungus Penicillium pancosmium A6A

Two undescribed 3,5-dimethylorsellinic acid (DMOA) derived meroterpenoids, namely pancosterpenoids A (1) and B (2), were discovered from the EtOAc extract of the deep-sea sediment-derived fungus Penicillium pancosmium A6A. The gross structures were established by detailed analysis of the spectroscopic data (NMR and HRESIMS spectra), while their absolute configurations were resolved by comparing the experimental and calculated ECD data as well as X-ray single crystal diffraction analysis. Pancosterpenoid A (1) was the first representative of DMOA-derived meroterpenoids possessing a 6/6/6/5/5 pentacyclic system, while pancosterpenoid B (2) belongs to a class of rare 13-nor-citreohybridone meroterpenoids. Two metabolites were evaluated the antiviral effects against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) trVLP pseudovirus. As a result, compounds 1 and 2 showed moderately inhibitory activities with IC50 values of 22.37 and 18.12 μM, respectively.

Penisimplinoids A-K, highly oxygenated andrastin-type meroterpenoids with diverse activities from the marine-derived fungus Penicillium simplicissimum

Penisimplinoid A (1), the first andrastin-type meroterpenoid with an unprecedented 6/6/3/6/5/5 polycyclic systems, together with ten highly oxygenated andrastin-type meroterpenoids (2-11) and one known analogue (12), were co-isolated from the marine-derived fungus Penicillium simplicissimum. Their absolute configurations were determined by single-crystal X-ray diffraction analysis (Cu Kα), DP4+ probability analyses, and ECD quantum chemistry calculations. Biological evaluation revealed that 7 and 12 showed anti-inflammatory activities in the zebrafish assay, 6 exhibited cytotoxic activity against NCI-H446 tumor cells with an IC50 value of 6.49 μM, 7 and 11 exhibited significant promoting angio-genesis activities.

Andrastin-type meroterpenoids, α-pyrone polyketides, and sesquicarane derivatives from Penicillium sp., a fungus isolated from Pinus koraiensis seed

The genus Penicillium has provided us with the household antibiotic penicillin and the well-known lipid-lowering agent mevastatin. The strain Penicillium sp. SZ-1 was found to grow vigorously in an intact Pinus koraiensis seed, it is inferred that the strain may develop unique mechanisms associated with the biosynthesis of rare metabolites. Further fermentation of the strain on solid rice medium yielded thirteen undescribed compounds, including three andrastin-type meroterpenoids (1-3), two α-pyrone polyketides (4 and 5), and eight sesquicarane derivatives (6-13), along with seven known compounds (14-20). Their structures were determined by detailed analysis of the spectroscopic and spectrometric data (NMR and HRESIMS), in addition to comparisons of the experimental and calculated ECD data for absolute configurational assignments. The hemiacetal moiety in compounds 1 and 2 and the 3α-hydroxy group in compound 3 were rarely found in the andrastin-type meroterpenoid family. The sesquicaranes belong to a small group of sesquiterpenoid that are rarely reported. Bioassay study showed that compound 1 exhibited inhibitory effects against Staphylococcus aureus ATCC 29213 and Escherichia coli ATCC 25922 with MIC values of 64 and 32 μg/mL, respectively. In addition, compounds 1 and 3 displayed weak DPPH radical scavenging activities. The andrastins and sesquicaranes in this study enriched the structural diversity of these classes of terpenoids. Of note, this study is the first report on the metabolites of a fungus isolated from P. koraiensis seed.

New Hydroxyphenylacetic Acids and α-Pyrone Derivative from the Deep-Sea Cold Seep Sediment-Derived Fungus Penicillium corylophilum CS-682

Two pairs of new enantiomeric hydroxyphenylacetic acid derivatives, (±)-corylophenols A and B ((±)-1 and (±)-2), a new α-pyrone analogue, corylopyrone A (3), and six andrastin-type meroterpenoids (4-9) were isolated and identified from the deep-sea cold-seep sediment-derived fungus Penicillium corylophilum CS-682. Their structures and stereo configurations were determined by detailed spectroscopic analysis of NMR and MS data, chiral HPLC analysis, J-based configuration analysis, and quantum chemical calculations of ECD, specific rotation, and NMR (with DP4+ probability analysis). Compound 3 showed inhibitory activity against some strains of pathogenic bacteria.

Asperustins A-J: Austocystins with Immunosuppressive and Cytotoxic Activities from Aspergillus ustus NRRL 5856

Ten new (1-10) and nine known (11-19) austocystins, along with four known anthraquinones (20-23), were isolated from the culture of Aspergillus ustus NRRL 5856 by bioactivity-guided fractionation. The structures of the new compounds were elucidated by spectroscopic data analysis, X-ray crystallographic study, the modified Mosher's method, [Rh2(OCOCF3)4]-induced ECD spectral analysis, and comparison of the experimental ECD spectra with those of the similar analogues. Compounds 1-8 represent the first examples of austocystins with a C-4' oxygenated substitution. The absolute configuration of 1″-hydroxy austocystin D (11) was determined by single-crystal X-ray diffraction and consideration of its biosynthetic origin. Compounds 5, 9, and 11 exhibited significant inhibitory effects against the proliferation of ConA-induced T cells with IC50 values of 1.1, 1.0, and 0.93 μM, respectively. Furthermore, these compounds suppressed the expression of IL-6 in a dose-dependent manner. Compounds 10-12 and 14 showed pronounced cytotoxicities against MCF-7 with IC50 values of 3.9, 1.3, 0.46, and 2.3 μM, respectively.

Discovery of adamantane-type polycyclic polyprenylated acylphloroglucinols that can prevent concanavalin A-induced autoimmune hepatitis in mice

Hyperadamans A-G (1-7), seven new adamantane type polycyclic polyprenylated acylphloroglucinols (PPAPs), were isolated from Hypericum wilsonii N. Robson. Structurally, 1-4 were the first adamantanes bearing an unusual 2,7-dioxabicyclo-[2.2.1]-heptane fragment, and compound 5 was the first adamantane with a rare 1,6-dioxaspiro[4.4]nonane section. Importantly, 1-7 exhibited significant immunosuppressive activity on Con A-induced T-lymphocyte proliferation in vitro, with IC50 values ranging from 3.97 ± 0.10 to 18.12 ± 1.07 μM. Pretreatment with 1 in Con A-challenged autoimmune hepatitis mice could dramatically ameliorate the levels of hepatic injury indexes (ALT and AST) and reduce the product of proinflammatory cytokines (COX-2, IL-6, IL-1β, IL-18, IL-23A and TNF-α). Furthermore, the protective effect of 1 on the Con A-induced liver injury was corroborated by the histological analysis and the immunohistochemistry.

Bialorastins A-F, highly oxygenated and polycyclic andrastin-type meroterpenoids with proangiogenic activity from the deep-sea cold-seep-derived fungus Penicillium bialowiezense CS-283

Six new highly oxygenated and polycyclic andrastin-type meroterpenoids, namely, bialorastins A-F (1-6), were discovered from the culture of Penicillium bialowiezense CS-283, a fungus isolated from the deep-sea cold seep squat lobster Shinkaia crosnieri. The planar structures and absolute configurations of these compounds were determined by detailed analysis of spectroscopic data, single crystal X-ray diffraction, and TDDFT-ECD calculations. Structurally, bialorastin A (1) represents a rare 17-nor-andrastin that possesses an unusual 2-oxaspiro[4.5]decane-1,4-dione moiety with a unique 6/6/6/6/5 polycyclic system, while bialorastin B (2) is also a 17-nor-andrastin featuring a gem-propane-1,2-dione moiety. Additionally, bialorastins C-E (3-5) possess a 6/6/6/6/5/5 fused hexacyclic skeleton, characterized by distinctive 3,23-acetal/lactone-bridged functionalities. All isolated compounds were evaluated for their proangiogenic activities in transgenic zebrafish. Compound 3 exhibited significant proangiogenic activity, which notably increased the number and length of intersegmental blood vessels in model zebrafish in a dose-dependent manner at concentrations of 20 and 40 μM. On a molecular scale, the tested compounds were modeled through molecular docking to have insight into the interactions with the possible target VEGFR2. Mechanistically, RT-qPCR results revealed that compound 3 could promote angiogenesis via activating VEGFR2 and subsequently activating the downstream PI3K/AKT and MAPK signaling pathways. These findings indicate that 3 could be a potential lead compound for developing angiogenesis agents.

Diaporaustalides A-L, Austalide Meroterpenoids from a Plant Endophytic Diaporthe sp

Twelve new austalide meroterpenoids (1-12) were isolated from the endophytic fungus Diaporthe sp. XC1211. Their structures were elucidated by extensive spectroscopic analysis. The absolute configurations of compounds 1, 3, 4, and 6 were established by single-crystal X-ray diffraction, whereas those for the others were established by experimental electronic circular dichroism (ECD) data analysis. Compounds 1-12 represent a rare class of austalides with a 24α-CH3. Compounds 2 and 5 demonstrated potent proliferation inhibitory effects against LPS-induced B cells with IC50 values of 6.7 (SI = 3.6) and 3.8 (SI > 13) μM, respectively. Compounds 2 and 5 decreased the secretion of IL-6 in LPS-induced B cells in a dose-dependent manner.