Two new aromatic polyketides from a deep-sea fungus Penicillium sp. SCSIO 06720

Metabolic and pharmacological profiling of Penicillium claviforme by a combination of experimental and bioinformatic approaches

BACKGROUND

Penicillium produces a wide range of structurally diverse metabolites with significant pharmacological impacts in medicine and agriculture. For the first time, a complete metabolome of Penicillium claviforme (P. claviforme) (FBP-DNA-1205) was studied alongside pharmacological research in this study.

METHODS

The metabolic profile of P. claviforme fermented on Potato Dextrose Broth (PDB) was investigated in this work. The complete metabolomics studies of fungus were performed using GC-MS and LC-MS-QTOF techniques. An in vitro model was utilised to study the cytotoxic and antioxidant activities, while an in vivo model was employed to investigate the antinociceptive and acute toxicity activities. Molecular Operating Environment (MOE) software was used for molecular docking analysis.

RESULTS

GC-MS study showed the presence of alkanes, fatty acids, esters, azo and alcoholic compounds. Maculosin, obtain, phalluside, quinoline, 4,4'-diaminostilbene, funaltrexamine, amobarbital, and fraxetin were among the secondary metabolites identified using the LC-MS-QTOF technique. The n-hexane fraction of P. claviforme displayed significant cytotoxic activity in vitro, with an LD50 value of 92.22 µgml^-1. The antinociceptive effects in vivo were dose-dependent significantly (p < .001). Interestingly, during the 72 h of investigation, no acute toxicity was demonstrated. In addition, a docking study of tentatively identified metabolites against the inflammatory enzyme (COX-2) supported the antinociceptive effect in an in silico model.

CONCLUSION

Metabolic profile of P. claviforme shows the presence of biologically relevant compounds in ethyl acetate extract. In addition, P. claviforme exhibits substantial antioxidant and cytotoxic activities in an in vitro model as well as antinociceptive activity in an in vivo model. The antinociceptive action is also supported by a molecular docking study. This research has opened up new possibilities in the disciplines of mycology, agriculture, and pharmaceutics. Key messagesThe first time explored complete metabolome through GC-MS and LC-MS-QTOF.Both in vivo & in vitro pharmacological investigation of P. claviforme.In silico molecular docking of LC-MS-QTOF metabolites.

Marine natural products

Covering: 2020This review covers the literature published in 2020 for marine natural products (MNPs), with 757 citations (747 for the period January to December 2020) referring to compounds isolated from marine microorganisms and phytoplankton, green, brown and red algae, sponges, cnidarians, bryozoans, molluscs, tunicates, echinoderms, mangroves and other intertidal plants and microorganisms. The emphasis is on new compounds (1407 in 420 papers for 2020), together with the relevant biological activities, source organisms and country of origin. Pertinent reviews, biosynthetic studies, first syntheses, and syntheses that led to the revision of structures or stereochemistries, have been included. A meta analysis of bioactivity data relating to new MNPs reported over the last five years is also presented.

New Tetramic Acid Derivatives From the Deep-Sea-Derived Fungus Penicillium sp. SCSIO06868 With SARS-CoV-2 Mpro Inhibitory Activity Evaluation

Three new tetramic acid derivatives (1–3) and a new polyketide (4) along with eight known compounds (5–12) were isolated from cultures of the deep-sea-derived fungus Penicillium sp. SCSIO06868. Four new structures were elucidated by analysis of one-dimensional/two-dimensional nuclear magnetic resonance (NMR) data and high-resolution electrospray ionization mass spectrometry. Their absolute configurations were established by X-ray crystallography analysis and comparison of the experimental and reported electronic circular dichroism (ECD) values or specific optical rotation. Compound 3 exhibited potent, selective inhibitory activities against Staphylococcus aureus and methicillin-resistant S. aureus with minimum inhibitory concentration values of both 2.5 μg/ml. Also, compound 3 showed weak antiviral activity against severe acute respiratory syndrome coronavirus 2 main protease, which was responsible for the coronavirus disease 2019 pandemic.

Three new unsaturated fatty acids from marine-derived fungus Aspergillus sp. SCAU150

Four unsaturated fatty acid derivatives including three new pantheric acids (1-3), together with three known polyketides (5-7), were isolated from a culture broth of the marine-derived fungus Aspergillus sp. SCAU150. Their complete structures were determined by NMR and HRESIMS data analyses. The antifungal activity of the isolated compounds above was evaluated and 2 was found to show moderated activity toward the phytopathogenic fungus Fusarium solani bio-80814 with an inhibition zone diameter of 6 mm under 5 µg/disc.

Antibiotics from Extremophilic Micromycetes

Extremophilic microorganisms, which are capable of functioning normally at extremely high or low temperatures, pressure, and in other environmental conditions, have been in the focus of microbiologists' attention for several decades due to the biotechnological potential of enzymes inherent in extremophiles. These enzymes (also called extremozymes) are used in the production of food and detergents and other industries. At the same time, the inhabitants of extreme econiches remained almost unexplored for a long time in terms of the chemistry of natural compounds. In recent years, the emergence of new antibiotic-resistant strains of pathogens, which affect humans and animals has become a global problem. The problem is compounded by a strong slowdown in the development of new antibiotics. In search of new active substances and scaffolds for medical chemistry, researchers turn to unexplored natural sources. In recent years, there has been a sharp increase in the number of studies on secondary metabolites produced by extremophiles. From the discovery of penicillin to the present day, micromycetes, along with actinobacteria, are one of the most productive sources of antibiotic compounds for medicine and agriculture. Many authors consider extremophilic micromycetes as a promising source of small molecules with an unusual mechanism of action or significant structural novelty. This review summarizes the latest (for 2018-2019) experimental data on antibiotic compounds, which are produced by extremophilic micromycetes with various types of adaptation. Active metabolites are classified by the type of structure and biosynthetic origin. The data on the biological activity of the isolated metabolites are summarized.

Molecules derived from the extremes of life: a decade later

Covering: Early 2008 until the end of 2019Microorganisms which survive (extreme-tolerant) or even prefer (extremophilic) living at the limits of pH, temperature, salinity and pressure found on earth have proven to be a rich source of novel structures. In this update we summarise the wide variety of new molecules which have been isolated from extremophilic and extreme-tolerant microorganisms since our original 2009 review, highlighting the range of bioactivities these molecules have been reported to possess.

Antioxidant CPA-type indole alkaloids produced from the deep-sea derived fungus Aspergillus sp. SCSIO 41024

Twelve indole alkaloids, including α-cyclopiazonic acid (CPA) (1), nine 2-oxo indole CPA derivatives (2-10), and two open-ring indole CPA derivatives (11 and 12), were isolated from the fermentation broth of a deep-sea derived fungus Aspergillus sp. SCSIO 41024. Their structures and absolute configurations were elucidated mainly by using extensive NMR spectroscopic, mass spectrometric and single crystal X-ray diffraction analysis. To the best of our knowledge, the crystallographic data of 3 and 7 were firstly reported, and the absolute configuration of 3 was confirmed for the first time by the single crystal X-ray diffraction analysis. Most isolated compounds were tested for their antimicrobial, antitumor and radical scavenging activities. In addition, compounds 1, 2 and 11 showed moderate antioxidative activity against DPPH with IC₅₀ values of 190.1, 31.9, 228.4 μg/mL, respectively.

Rabenchromenone and Rabenzophenone, Phytotoxic Tetrasubstituted Chromenone and Hexasubstituted Benzophenone Constituents Produced by the Oak-Decline-Associated Fungus Fimetariella rabenhorstii

A new phytotoxic tetrasubstituted chromen-4-one (1) and a new hexasubstituted benzophenone (2), named rabenchromenone and rabenzophenone, respectively, were isolated from the culture filtrates of Fimetariella rabenhorstii, an oak-decline-associated fungus in Iran. Rabenchromenone and rabenzophenone, isolated together with known moniliphenone (3) and coniochaetone A (4), were characterized as methyl 3-chloro-1,8-dihydroxy-6-methyl-9-oxo-1,9-dihydrocyclopenta[b]chromene-1-carboxylate and methyl 4-chloro-2-(2,6-dihydroxy-4-methylbenzoyl)-3-hydroxybenzoate, respectively, by spectroscopic methods (primarily nuclear magnetic resonance and high-resolution electrospray ionization mass spectrometry). The R absolute configuration at C-1 of rabenchromenone was determined by quantum chemical calculations and electronic circular dichroism experiments. All metabolites (1-4) were tested by leaf puncture on tomato and oak plants. All compounds were active in this assay by causing in both plants a necrosis diameter in the range of 0.2-0.7 cm. Specifically, rabenzophenone (2) was found to be the most phytotoxic compound in both plants.

Antibiotics Development and the Potentials of Marine-Derived Compounds to Stem the Tide of Multidrug-Resistant Pathogenic Bacteria, Fungi, and Protozoa

As the search for new antibiotics continues, the resistance to known antimicrobial compounds continues to increase. Many researchers around the world, in response to antibiotics resistance, have continued to search for new antimicrobial compounds in different ecological niches such as the marine environment. Marine habitats are one of the known and promising sources for bioactive compounds with antimicrobial potentials against currently drug-resistant strains of pathogenic microorganisms. For more than a decade, numerous antimicrobial compounds have been discovered from marine environments, with many more antimicrobials still being discovered every year. So far, only very few compounds are in preclinical and clinical trials. Research in marine natural products has resulted in the isolation and identification of numerous diverse and novel chemical compounds with potency against even drug-resistant pathogens. Some of these compounds, which mainly came from marine bacteria and fungi, have been classified into alkaloids, lactones, phenols, quinones, tannins, terpenes, glycosides, halogenated, polyketides, xanthones, macrocycles, peptides, and fatty acids. All these are geared towards discovering and isolating unique compounds with therapeutic potential, especially against multidrug-resistant pathogenic microorganisms. In this review, we tried to summarize published articles from 2015 to 2019 on antimicrobial compounds isolated from marine sources, including some of their chemical structures and tests performed against drug-resistant pathogens.

Two new phthalide derivatives from the endophytic fungus Penicillium vulpinum isolated from Sophora tonkinensis

Two new phthalide derivatives, (-)-3-carboxypropyl-7-hydroxyphthalide (1) and (-)-3-carboxypropyl-7-hydroxyphthalide methyl ester (2), were isolated from the endophytic fungus Penicillium vulpinum isolated from the Chinese medicinal plant Sophora tonkinensis. Their structures were elucidated using spectroscopic methods, mainly on 1D and 2D NMR. Compound 1 exhibited medium antibacterial activities against Bacillus subtilis, Shigella dysenteriae and Enterobacter areogenes with MIC values of 12.5-25 μg/mL, and 2 showed a medium inhibition to E. areogenes with MIC value of 12.5 μg/mL.

Sesquiterpenoids and meroterpenoids from a mangrove derived fungus Diaporthe sp. SCSIO 41011

One new sesquiterpenoid, 1-methoxypestabacillin B (1), along with one known sesquiterpenoid (2) and six known chrodrimanin-type meroterpenoids (3‒8) were obtained from the solid cultures of a mangrove endophytic fungus Diaporthe sp. SCSIO 41011. Their structures including the absolute configuration at C-6 of compound 1, were determined by extensive spectroscopic analyses and ECD calculations. Meanwhile, the X-ray crystal structures and absolute configurations of two previously reported chrodrimanins E (3) and H (6), are described for the first time. All the compounds were examined for HIV latency-reversal and anti-influenza A virus activities.