Cannabinoid-like meroterpenoids from Peperomia incana.

Ten previously undescribed metabolites were isolated from Peperomia incana (Haw.) A. Dietr. (Piperaceae), among which four contained a chromene moiety, two were identified as meroterpene lactones, and four were cannabinoid-like compounds. While the chemical structures of the compounds were assigned based on HRESIMS and 1D and 2D-NMR spectra analyses, the relative and absolute configurations were assigned from NOE correlations and a combination of ECD data and X-ray single crystal analyses, respectively. In a cytotoxic assay against a panel of seven human cancer cell lines (A549, MDA-MB-231, HeLa, DU 145, 5637, Hep G2, and MIA PaCa-2, which represent non-small cell lung cancer, as well as breast, cervical, prostate, bladder, liver, and pancreas carcinomas, respectively) most of the isolated compounds showed promising cytotoxic activities. The incanachromenes B, and incanabinoids A and C exhibited the highest cytotoxicity toward all tested cancer cell lines with IC50 values in the range of 5.0-10.0 µM, whereas incanolides A, B, and incanabinoid B showed the lowest cytotoxic activity. In addition, incanachromene C and incanabinoid C produced a significant antibacterial effect toward planktonic cells and biofilms of multidrug-resistant Staphylococcus aureus strains.

Mosquitocidal Activity of the Methanolic Extract of Annickiachlorantha and Its Isolated Compounds against Culex pipiens, and Their Impact on the Non-Target Organism Zebrafish, Danio rerio.

In this study, the crude extract and its isolated compounds from the stem bark of Annickia chlorantha were tested for their larvicidal, developmental, and repellent activity against the mosquito vector, Culex pipiens, besides their toxicity to the non-target aquatic organism, the zebrafish (Danio rerio). The acute larvicidal activity of isolated compounds; namely, palmatine, jatrorrhizine, columbamine, ß-sitosterol, and Annickia chlorantha methanolic extract (AC), was observed. Developmentally, the larval duration was significantly prolonged when palmatine and ß-sitosterol were applied, whereas the pupal duration was significantly prolonged for almost all treatments except palmatine and jatrorrhizine, where it shortened from those in the control. Acetylcholinesterase (AChE) enzyme showed different activity patterns, where it significantly increased in columbamine and ß-sitosterol, and decreased in (AC), palmatine, and jatrorrhizine treatments, whereas glutathione S-transferase (GST) enzyme was significantly increased when AC methanolic extract/isolated compounds were applied, compared to the control. The adult emergence percentages were significantly decreased in all treatments, whereas tested compounds revealed non-significant (p > 0.05) changes in the sex ratio percentages, with a slight female-to-male preference presented in the AC-treated group. Additionally, the tested materials revealed repellence action; interestingly, palmatine and jatrorrhizine recorded higher levels of protection, followed by AC, columbamine, and ß-sitosterol for 7 consecutive hours compared to the negative and positive control groups. The non-target assay confirms that the tested materials have very low toxic activity compared to the reported toxicity against mosquito larvae. A docking simulation was employed to better understand the interaction of the isolated compounds with the enzymes, AChE and GST. Additionally, DFT calculations revealed that the reported larvicidal activity may be due to the differing electron distributions among tested compounds. Overall, this study highlights the potential of A. chlorantha extract and its isolated compounds as effective mosquitocidal agents with a very low toxic effect on non-target organisms.

Thiazolidinedione Derivatives: In Silico, In Vitro, In Vivo, Antioxidant and Anti-Diabetic Evaluation.

This work aimed to synthesize a new antihyperglycemic thiazolidinedione based on the spectral data. The DFT\B3LYP\6-311G** level of theory was used to investigate the frontier molecular orbitals (FMOs), chemical reactivity and map the molecular electrostatic potentials (MEPs) to explain how the synthesized compounds interacted with the receptor. The molecular docking simulations into the active sites of PPAR-γ and α-amylase were performed. The in vitro potency of these compounds via α-amylase and radical scavenging were evaluated. The data revealed that compounds (4-6) have higher potency than the reference drugs. The anti-diabetic and anti-hyperlipidemic activities for thiazolidine-2,4-dione have been investigated in vivo using the alloxan-induced diabetic rat model along with the 30 days of treatment protocol. The investigated compounds didn't show obvious reduction of blood glucose during pre-treatments compared to diabetic control, while after 30 days of treatments, the blood glucose level was lower than that of the diabetic control. Compounds (4-7) were able to regulate hyperlipidemia levels (cholesterol, triglyceride, high-density lipoproteins and low- and very-low-density lipoproteins) to nearly normal value at the 30th day.

Synthesis of ß-Enaminonitrile-Linked 8-Methoxy-1H-Benzo[f]Chromene Moieties and Analysis of Their Antitumor Mechanisms.

A series of aryl-substituted 3-amino-1-aryl-8-methoxy-1H-benzo[f]chromene-2-carbonitriles (4a-4q) were designed and synthesized via reaction of 6-methoxy-2-naphthol with a mixture of appropriate aromatic aldehydes and malononitrile under microwave conditions. The structures of the novel compounds 4b, 4c, 4f, 4g, 4i, 4l, 4m, and 4o-4q were established according to IR, 1H-NMR, 13C-NMR/13C-NMR-DEPT, and MS. The benzochromene derivative 4c with a single chlorine at the meta position of the phenyl ring and, to a lesser extent, other benzochromenes with monohalogenated phenyl ring (4a, 4c-4f) exhibited the highest cytotoxicity against six human cancer cell lines MDA-MB-231, A549, HeLa, MIA PaCa-2, 5,637, and Hep G2. The mechanisms of the cytotoxic activities of benzochromenes with monohalogenated phenyl ring (4a, 4c-4f) were further analyzed using triple-negative breast cancer cell line MDA-MB-231. Cell cycle analysis showed accumulation of the treated cells in S phase for 4a, 4d-4f, and S-G2/M phases for 4c. In vivo, 4a and 4c-4f inhibited growth, proliferation, and triggered apoptosis in preestablished breast cancer xenografts grown on the chick chorioallantoic membranes while exhibiting low systemic toxicity. Compounds 4a and 4c-4f increased levels of mitochondrial superoxide and decreased mitochondrial membrane potential resulting in initiation of apoptosis as demonstrated by caspase 3/7 activation. In addition, 4c induced general oxidative stress in cancer cells. The SAR study confirmed that halogens of moderate size at meta or para positions of the pendant phenyl ring enhance the cytotoxic activity of 3-amino-1-aryl-8-methoxy-1H-benzo[f]chromene-2-carbonitriles, and these compounds could serve as leads for the development of novel anticancer therapies.

Synthesis and evaluation of antitumor activity of 9-methoxy-1H-benzo[f]chromene derivatives.

Herein, a series of aryl-substituted derivatives of 3-amino-1-aryl-9-methoxy-1H-benzo[f]chromene-2-carbonitriles (4a-4q) were designed and synthesized via reaction of 7-methoxy-2-naphthol with a mixture of appropriate aromatic aldehydes and malononitrile under microwave conditions. Among the tested benzochromene, the known compound 4e and four novel compounds 4f, 4j, 4k, 4m exhibited the highest cytotoxicity towards a panel of six human cancer cell lines MDA-MB-231, A549, HeLa, MIA PaCa-2, RPMI 7951, and PC-3. Compound 4j with 2,4-dichloro substitution on the pendant phenyl ring exhibited the highest broad-spectrum cytotoxicity towards all tested cancer cell lines. Compounds 4e, 4f, 4j, 4k, 4m were further selected to study the mechanism of cellular toxicity using the triple-negative breast cancer cells MDA-MB-231. Compounds 4e, 4f, 4j, 4k, 4m induced accumulation of the treated MDA-MB-231 cells in the S phase and 4k additionally in the G2/M phase of the cell cycle. Compounds 4e, 4f, 4j, 4k, 4m induced dissipation of mitochondrial transmembrane potential and activation of caspase 3/7 in MDA-MB-231 cells with 4j being one of the most active. In an in vivo model, compound 4j and less efficiently 4e and 4f inhibited growth and proliferation and triggered DNA fragmentation in MDA-MB-231 xenografts grown on chick chorioallantoic membranes. SAR study confirmed that the 2,4-dichloro substitution pattern on the pendant phenyl ring enhanced the cytotoxic activity of benzochromene.

Meleagrin from marine fungus Emericella dentata Nq45: crystal structure and diverse biological activity studies.

The crystal structure and unambiguous absolute configuration of meleagrin (1) isolated from fungus Emericella dentata Nq45 is reported herein to first time on the bases of single crystal X-ray diffraction. Together with 1, haenamindole (2), isorugulosuvine (3), secalonic acid D (4), ergosterol (5) and cerebroside A (6) were obtained and their structures were determined by ESI MS and NMR data analysis. Diverse biological activity of meleagrin (1) was investigated. Compound 1 pronounced potent cytotoxicity against the human cervix carcinoma cell line KB-3-1 and its multidrug resistant sub-clone KB-V1 of IC50 3.07 and 6.07 µM, respectively, in comparison with the reference (+) - griseofulvin (IC50 19, 19.5 µM). Based on the antibiofilm activity, compound 1 displayed as well potent activity against Staphylococcus aureus with an MIC of 0.25 mg/mL. Isolation of the producing fungus and taxonomical characterization is stated as well.

The Arsenal of Bioactive Molecules in the Skin Secretion of Urodele Amphibians.

Urodele amphibians (∼768 spp.), salamanders and newts, are a rich source of molecules with bioactive properties, especially those isolated from their skin secretions. These include pharmacological attributes, such as antimicrobial, antioxidant, vasoactive, immune system modulation, and dermal wound healing activities. Considering the high demand for new compounds to guide the discovery of new drugs to treat conventional and novel diseases, this review summarizes the characteristics of molecules identified in the skin of urodele amphibians. We describe urodele-derived peptides and alkaloids, with emphasis on their biological activities, which can be considered new scaffolds for the pharmaceutical industry. Although much more attention has been given to anurans, bioactive molecules produced by urodeles have the potential to be used for biotechnological purposes and stand as viable alternatives for the development of therapeutic agents.

RF-3192C and other polyketides from the marine endophytic Aspergillus niger ASSB4: structure assignment and bioactivity investigation.

Chemical investigation of the methanolic extract of endophytic Aspergillus niger SB4, isolated from the marine alga Laurencia obtuse, afforded the pentacyclic polyketide, RF-3192C (1), the dimeric coumarin orlandin (2), fonsecin B (3), TMC-256A1 (4), cyclo-(Leu-Ala) (5), and cerebroside A (6).The chemical structure of RF-3192C (1) is assigned herein for the first time using 1D/2D NMR and HRESI-MS. Additionally, the revision of the NMR assignments of orlandin (2) was reported herein as well. Investigation of the antimicrobial activities of isolated compounds revealed the high activity of RF-3192C (1) against Pseudomonas aeruginosa and Bacillus subtilis, and moderate activity against yeast. Moreover, an in vitro cytotoxic activity against liver (HEPG2), cervical (HELA), lung (A549), prostate (PC3), and breast (MCF7) cancer cell lines of the isolated compounds was evaluated. The isolation and taxonomical characterization of the producing fungus was reported as well.

Synthesis of novel feruloyl dipeptides with proapoptotic potential against different cancer cell lines.

In this study, a series of novel N-feruloyl dipeptides (10-17) have been synthesized through the coupling of N-feruloyl amino acids (6-9) with glycine/alanine methyl ester hydrochloride. Structures of the peptides were assigned using 1D and 2D NMR and HRESIMS. According to initial in vitro cytotoxic screening against the cervix carcinoma cell line KB-3-1, aromatic dipeptides (12, 13, 16, 17) were the most potent ones among all tested feruloyl dipeptides. Accordingly, these peptides were further intensively investigated as potential anticancer agents against a panel of ten cancer cell lines from different tissue origin. Based on that, compound 17 showed the strongest cytotoxic efficiency towards the whole panel of tested cell lines with IC50 values from 2.1 to 7.9 µM. By contrast, the dipeptides 12, 13 and 16 showed moderate to weak cytotoxicity (IC50 16.1-28.3 or >30, 5.7-21.9 and 3.9-21.2 or ≥30 µM, respectively). Mechanistically, compound 17 induced a strong dissipation of the mitochondrial transmembrane potential and an early activation of caspase 3/7 in the triple-negative MDA-MB-231 breast cancer cell line. In an in vivo model, compound 17 inhibited growth, proliferation and induced apoptosis in MDA-MB-231 xenografted onto the chick chorioallantoic membrane. All the synthesized compounds were also tested against a set of pathogenic bacterial strains, displaying no potential activity.

Purification and characterization of seven bioactive compounds from the newly isolated Streptomyces cavourensis TN638 strain via solid-state fermentation.

The strain TN638 was isolated from Tunisian soil contaminated with industrial wastewater and selected for its potent antimicrobial activity against the tested Gram positive bacteria: Staphylococcus aureus (S. aureus) ATCC 6538 and Listeria monocytogenes (L. monocytogenes) ATCCC 19117, and Gram negative bacteria: Agrobacterium tumefaciens (A. tumefaciens) ATCC 23308 and Salmonella typhimurium (S. typhimurium) ATCC 14028 and fungi: Candida albicans (C. albicans) ATCC 10231, Rhizoctonia solani (R. solani) ATCC 58938 and Fusarium sp. Solide-state fermentation (SSF) dry crude extract of the TN638 strain presents a strong inhibitory activity notably against the phytopathogenic microorganism A. tumefaciens ATCC 23308 and the two pathogenic bacteria S. aureus ATCC 6538 and L. monocytogenes ATCCC 19117 with a zone of inhibition of 48, 34 and 34 mm respectively. According to the morphological characteristic, the complete 16S rRNA gene nucleotide sequence determination [1492 bp deposited in National Center of Biotechnology Information (NCBI) database under the accession no. LN854629.1; https://www.ncbi.nlm.nih.gov/nuccore/LN854629.1/], and the phylogenetic analysis, we can deduce that our isolate is an actinomycete bacterium belonging to the genus Streptomyces and the most closely related strain was Streptomyces cavourensis (S. cavourensis) NRRL 2740T (99.9%). We propose the assignment of our strain as Streptomyces cavourensis (S. cavourensis) TN638 strain. Work-up and purification of the strain extract using different chromatographic techniques afforded seven bio-compounds namely: Cyclo-(Leu-Pro) (1), Cyclo-(Val-Pro) (2), Cyclo-(Phe-Pro) (3), nonactin (4), monactin (5), dinactin (6) and trinactin (7). The chemical structures of compounds 1-7 were confirmed by nuclear magnetic resonance (NMR) 1D and 2D spectroscopy, mass spectrometry, and comparison with literature data. The three purified diketopiperazine (DKP) derivatives (1-3), demonstrated significant antibacterial activity against A. tumefaciens ATCC 23308 and S. typhimurium ATCC 14028. The four pure macrotetrolides (4-7), exhibited strong inhibitory effect against all tested Gram positive and Gram negative bacteria notably against A. tumefaciens ATCC 23308 and S. typhimurium ATCC 14028 with a minimum inhibitory concentration (MIC) around 8 µg/mL quite similar to that of ampicillin. Thus, we propose the use of the (SSF) active extract of the S. cavourensis TN638 strain as safe biological product to control disease caused by plant pathogen A. tumefaciens. Also, the purified active molecules produced by this strain could be used in pharmaceutical field.

Terretonin O: a new meroterpenoid from Aspergillus terreus.

Terretonin O (1), a new meroterpenoid, was isolated individually from both methanolic extracts of thermophilic Aspergillus terreus TM8 and marine Aspergillus terreus LGO13. The recently reported terretonins M (2) and N (3) were further isolated from the fungus LGO13 along with nine known compounds, terrelumamide A (4), terrein (5), methyl-3,4,5-trimethoxyl-2-[2-(nicotinamide)benzamido] benzoate (6), butyrolactones I-III (7-9), aspulvinone O (10), ergosterol, ergost-4-ene-3-one and methyl linoleate. Structure of terretonin O (1) was established on the bases of HRESIMS, 1D and 2D NMR spectra and comparison with its analogues in literatures. The relative stereochemistry of 1 was assigned on the basis of NOESY spectra and comparison with reported configuration of its congener compounds 2 and 3. The antimicrobial and cytotoxic activities of the fungal extracts and obtained compounds were assayed using a set of microorganisms, and cervix carcinoma cell line (KB-3-1), respectively. Isolation and taxonomical characterization of the producing strains are reported.

Isoshamixanthone: a new pyrano xanthone from endophytic Aspergillus sp. ASCLA and absolute configuration of epiisoshamixanthone.

Isoshamixanthone (1), a new stereoisomeric pyrano xanthone together with the previously known fungal metabolites, epiisoshamixanthone (2), sterigmatocystin (3), arugosin C (4), norlichexanthone (5), diorcinol (6), ergosterol and methyllinoleate, were obtained from the endophytic fungal strain Aspergillus sp. ASCLA isolated from leaf tissues of the medicinal plant Callistemon subulatus. The chemical structure of the new xanthone (1) was elucidated by extensive 1D, 2D NMR, and ESI HR mass measurements, and by comparison with literature data. The constitutions and absolute configurations of 1 and epiisoshamixanthone (2) were additionally confirmed by X-ray crystallography. Compounds 1,2 were evaluated for their potential anticancer activity using the human cervix carcinoma cell line (KB-3-1). The antimicrobial activities of the fungal extract and compounds 1,2 were studied using a panel of pathogenic microorganisms as well.

Coumamarin: a first coumarinyl calcium complex isolated from nature.

The first calcium complex from nature, Coumamarin (1), 7-hydroxy-3-methoxy-2-oxo-2H-chromene-6-carboxylate Ca(II) complex, was isolated from Aspergillus sydowii ASTI, together with diorcinol (2), violaceol I (3), hydroxysydonic acid (4), cyclo (Trp-Phe), kojic acid, ergosterol, and uracil. The producing strain was isolated from marine water sample collected from Tiran Island, Red Sea, Egypt. Structure 1 was assigned by intensive 1D, 2D NMR, HR-ESIMS, and X-ray crystallography as well. Coumamarin is potentially active against certain tested bacteria and yeasts, while showing no cytotoxic activity against human cervix carcinoma cell line (KB-3-1). Taxonomically, the fungus was identified by phylogenetic analysis of its 18S rRNA gene sequence.

Bioactive secondary metabolites from new endophytic fungus Curvularia. sp isolated from Rauwolfia macrophylla.

Over the last decades, endophytic fungi represent a new source of pharmacologically active secondary metabolites based on the underlying assumption that they live symbiotically within their plant host. In the present study, a new endophytic fungus was isolated from Rauwolfia macrophylla, a medicinal plant from Cameroon. The fungus showed a highest homology to Curvularia sp. based on complete nucleotide sequence data generated from the internal transcribed spacer (ITS) of ribosomal DNA region. Large scale fermentation, working-up and separation of the strain extract using different chromatographic techniques afforded three bioactive compounds: 2'-deoxyribolactone (1), hexylitaconic acid (2) and ergosterol (3). The chemical structures of compounds 1-3 were confirmed by 1 and 2D NMR spectroscopy and mass spectrometry, and comparison with corresponding literature data. Biologically, the antimicrobial, antioxidant activities and the acetylcholinesterase inhibitory of the isolated compounds were studied.

Diverse polyketides and alkaloids from Penicillium sp. KHMM: structural elucidation, biological and molecular docking studies.

As a continuation of our earlier research concerning the investigation of microbial bioactive secondary metabolites from the terrestrial Penicillium sp.KH Link 1809 isolate KHMM, the fungus was re-cultivated on a large scale to explore its bioactive compounds intensively. Fifteen compounds, including seven alkaloids (1-7), one sesquiterpene (8), an acetylenic system (9), two sterols, and sphengolipid, were identified. Their structures were established on the bases of extensive one- and two-dimensional nuclear magnetic resonance and mass measurements, and by comparison with literature data. The antimicrobial activity of the fungal extract and the corresponding compounds were studied using a panel of pathogenic microorganisms, and their in vitro cytotoxicity against the human cervix carcinoma cell line (KB-3-1) was reported as well. The molecular docking of the isolated compounds showed promising affinities for the alkaloidal compounds 4-6 towards α, ß tubulins.

Crystal structure and configuration revision of 9-hydroxy-7,8-dehydro-sarcotrocheliol and sarcotrocheliol.

Herein, we report the isolation and stereo-structure of rare pyrane-based cembranoid diterpenes, 9-hydroxy-7,8-dehydro-sarcotrocheliol (1) and sarcotrocheliol (2), from Sarcophyton trocheliophorum collected from Red Sea. Absolute configurations of both compounds were revised based on single crystal X-ray analyses.

X-ray, structural assignment and molecular docking study of dihydrogeodin from Aspergillus Terreus TM8.

A re-cultivation of the thermophilic fungus Aspergillus terreus TM8, and working up of its extract afforded the dichloro-benzophenone derivative, dihydrogeodin (1) in addition to the butyrolactones I (2), V (3) and VI (4). A literature surveying revealed one recent structural assignment trial for dihydrogeodin (1), however, with some inaccuracies. We report herein a full assignment of dihydrogeodin (1) using extensive study of 1D, 2D NMR and ESI HR mass data. For the first time as well, we report the planar structure of 1 using X-ray crystallography. Docking and molecular dynamic simulation of dihydrogeodin (1) on the isomerase cyclophilin A has revealed its significant potential activity as an antiviral and immunosuppressive agent.

New pyranosyl cembranoid diterpenes from Sarcophyton trocheliophorum.

During our continual searching programme for novel bioactive metabolites from Sarcophyton trocheliophorum, collected from Red Sea, we describe herein the isolation and structural elucidation of further two new pyrane-based cembranoid diterpenes: 9-hydroxy-7,8-dehydro-sarcotrocheliol (1) and 8,9-expoy-sarcotrocheliol acetate (2), along with the well-known sarcotrocheliol acetate (3), (+)-sarcophine (4), (+)-sarcophytoxide (5) and (-)-sarcophytoxide (6). The chemical structures of compounds 1 and 2 were determined on the basis of 1D and 2D NMR (1H, 13C, 1H-1H COSY, HMQC, HMBC and NOE), mass spectra (ESI and HR-ESIMS) and by comparison with related structures. The antimicrobial activities of the reported compounds 1-6 were investigated. According to the molecular docking study of compounds 1-6 using 3D structure of α,ß tubulin in complex with taxol (PDB code 1JFF) and epothilone A (PDB code 1TVK), sarcophine (4) displayed the highest affinity towards both crystal structures, followed by 5 and 6, meanwhile pyrane-based cembranoid diterpenes (1-3) showed less affinity.

Penicisteroid C: New polyoxygenated steroid produced by co-culturing of Streptomyces piomogenus with Aspergillus niger.

Penicisteroid C, a new polyoxygenated steroid was isolated from co-cultivation of Streptomyces piomogenus AS63D and Aspergillus niger using solid-state fermentation on rice medium. Additional diverse eleven known metabolites were identified: Fumigaclavine C, fumiquinazoline C, physcion, methylsulochrin, methyllinoleate, glycerol linoleate, cerebroside A, thymine, adenine, thymidine and adenosine. The structure of penicisteroid C was determined by HRESIMS, 1D and 2D NMR data. The antimicrobial and in vitro cytotoxic activities of the microbial extract and penicisteroid C were reported as well.

Ecological and Phytochemical Studies on Euphorbia retusa (Forssk.) from Egyptian Habitat.

This study deals with the ecology, phytochemistry, and biological activity investigation of Euphorbia retusa, belonging to Euphorbiaceae family, obtained from Egypt. Ecologically, Euphorbia retusa secretes white sap inhibiting the growth of the other species, so Euphorbia retusa is forming complete patches. Phytochemical study of the plant was visualized intensively based on its extraction with a protic organic solvent, working up and purifying its entire bioactive compounds using a series of different chromatographic techniques. A broad range of diverse compounds were isolated, namely, 1-hexacosanol (1), 3ß-hydroxy-24-methylene-9,19-cyclolanostane; 24-methylenecycloartanol (2), 3ß-hydroxy-9,19-cyclolanostane; cyclolaudanol (3), 3ß,24S-Ergost-5-en-ol (4), and methyllinoleate. Additionally, GC-MS analysis of the unpolar fractions detected the existence of n-dodecane, methyllaurate, 6,10,14-trimethyl-pentadecan-2-one (5), 6,10-dimethyl-undecan-2-one (6), 2-methyl-hexadecanal (7), methylpalmitate, methyl-9,12,15-octadecatrienoate (8), and n-heneicosane (9). A full assignment for compounds 2 and 3 using 1 and 2 DNMR was carried out herein for the first time. The antimicrobial activity of the strain extract and obtained compounds was studied using a panel of pathogenic bacterial strains. The in vitro cytotoxicity of the compounds as well as the crude extract was studied against the human cervix carcinoma cell line (KB-3-1).