Chemical constituents, in vitro anti-inflammatory, antioxidant and hemostatic activities of the n-butanol extract of Hyacinthoides lingulata (Poir.) Rothm.

The phytochemical profile obtained from LC-ESI-MS/MS analysis of the n-butanol extract (BEHL) from the North African endemic plant Hyacinthoides lingulata (Poir.) Rothm. brought about the identification of ten glycosylated derivatives of apigenin and luteolin flavones. For the same plant extract, in vitro anti-inflammatory (hypotonic induced hemolysis and heat induced haemolysis assay) and antioxidant (DPPH and ß-Carotene) activities were evaluated observing high inflammatory inhibition by protecting membrane stability of erythrocyte in both heat (84.70 ± 0.24%) and hypotonic induced hemolysis (79.45 ± 0.12%). A remarkable hemostatic effect was also established by measuring the coagulation time (15.95 ± 1.05 s at a dose of 1 mg/mL) of decalcified plasma related to its phytochemical content. It is the first report on combined chemical components and biological evaluation of this specific plant.

LC-ESI/MS-Phytochemical Profiling with Antioxidant, Antibacterial, Antifungal, Antiviral and In Silico Pharmacological Properties of Algerian Asphodelus tenuifolius (Cav.) Organic Extracts.

Asphodelus tenuifolius Cav. (A. tenuifolius) is a medicinal plant with a long history of traditional use to treat ailments. In this study, total phenolic and flavonoid content evaluation using LC-ESI/MS analysis and various biological activities (antioxidant, antibacterial, antifungal, antiviral and cytotoxicity) of organic extracts from the aerial parts of A. tenuifolius were analyzed. ADME tools were used to predict the potential of the identified compounds from the most potent extract as specific drugs. As shown, LC-ESI/MS results of chloroformic extract allowed the tentative identification of 12 compounds. Chloroformic extract was rich in polyphenols and flavonoids and exhibited the highest antioxidant activity given by DPPH (IC50 = 25 µg/mL) as compared to the BHT standard (11.5 µg/mL) and ß-carotene bleaching assays (IC50 = 95.692 µg/mL). Antibacterial activity results showed that chloroformic extract has a highest activity against Gram-positive and -negative bacteria, especially against Salmonella Typhimurium DT104 (IZ = 19.3 mm, MIC = 18.75 mg/mL, MBC = 37.5 mg/mL). The MBC/MIC ratio was evaluated to interpret the activity that was bacteriostatic rather than bactericidal. Conversely, weaker antifungal activity was registered, and no antiviral activity was observed for all extracts against Herpes Simplex Virus type 2 and Coxsakievirus B-3 viruses. Cytotoxic activity on VERO cell line results revealed that butanol extract was not toxic, with CC50 value of 1430 µg/mL, while chloroformic extract showed moderate cytotoxicity. Additionally, in silico studies performed proved promising pharmacokinetic and drug-likeness properties of the main compounds from the chloroformic extract. Taken together, this work highlights the potent bioactivity and acceptable drug-likeness of this plant, which supports its further preclinical development.

Pharmacological inactivation of the prion protein by targeting a folding intermediate.

Recent computational advancements in the simulation of biochemical processes allow investigating the mechanisms involved in protein regulation with realistic physics-based models, at an atomistic level of resolution. These techniques allowed us to design a drug discovery approach, named Pharmacological Protein Inactivation by Folding Intermediate Targeting (PPI-FIT), based on the rationale of negatively regulating protein levels by targeting folding intermediates. Here, PPI-FIT was tested for the first time on the cellular prion protein (PrP), a cell surface glycoprotein playing a key role in fatal and transmissible neurodegenerative pathologies known as prion diseases. We predicted the all-atom structure of an intermediate appearing along the folding pathway of PrP and identified four different small molecule ligands for this conformer, all capable of selectively lowering the load of the protein by promoting its degradation. Our data support the notion that the level of target proteins could be modulated by acting on their folding pathways, implying a previously unappreciated role for folding intermediates in the biological regulation of protein expression.

Chemical composition, in vitro antioxidant, anticholinesterase and antibacterial activities of Linaria scariosa Desf.

The study was performed on the dichloromethane (DCM), ethyl acetate (EAc) and n-butanol (Bu) fractions (F) obtained from the 80% ethanol extract of Linaria scariosa Desf. aerial parts, collected in the North Eastern region of Algeria. Remarkable total phenolic and flavonoid contents were obtained, mainly for EAcF. These results were in accordance with the antioxidant activity of EAcF against DPPH, ABTS, CUPRAC and reducing power tests. DCMF and BuF exhibited significant cholinesterase activity inhibition of BChE and AChE. Moreover, EAcF displayed only moderate antibacterial activities, especially against S. aureus. The biological results were correlated to the chemical components, deduced by both GC-MS analysis of the fractions and the isolation of hemipholin, pectolinarigenin, antirride, antirrinoside, pectolinarin and linariosise, some of which known to exhibit potent effects on the tested biological activities. The study provides the first biological and chemical investigation on Linaria scariosa Desf (unresolved name).

Anti-inflammatory and hemostatic effects of Linaria reflexa Desf.

The work presented here was aimed to investigate the in vivo anti-inflammatory and in vitro hemostatic activities of Linaria reflexa extract and to establish the relationship between its bioactivity and chemical composition. Twenty-three secondary metabolites were identified, most of them are good anti-inflammatory agents, in line with data by carrageenin-induced rat paw edema assays of the n-butanol extract showing high anti-inflammatory inhibition (63.90%) of edema swelling in the rat paw at the dose 200 mg/kg after 4 h. Furthermore, both extent of inflammatory response and tissue injury were prevented keeping the levels of rate myeloperoxidase (60.16%) and of malondialdehyde, which is the final product of lipid peroxidation generated by free radicals (58.58%). The same extract showed also a remarkable hemostatic effect established by measuring the coagulation time of decalcified plasma (45 s), related to its flavonoid glycosides content.

Isolation and Biological Properties of the Natural Flavonoids Pectolinarin and Pectolinarigenin-A Review.

Flavonoids are metabolites widely distributed in plants and commonly present in foods, such as fruits and vegetables. Pectolinarin, which belongs to the flavone subclass, has attracted considerable attention due to its presence in many medicinal plants. It has turned out to be a good biological agent especially due to its antioxidant, anti-inflammatory, antidiabetic, and antitumor activities, evaluated both in vitro and in vivo. Its aglycone, the metabolite pectolinarigenin, is also known for a series of biological properties including anti-inflammatory and antidiabetic effects. In the first overview on the two metabolites here presented, their collection, isolation and the results of their biological evaluation are reported.

Glucopyranosylbianthrones from the Algerian Asphodelus tenuifolius: Structural Insights and Biological Evaluation on Melanoma Cancer Cells.

Two new glucopyranosylbianthrones (1 and 2) were isolated from the aerial part of the plant Asphodelus tenuifolius, collected in Southwest Algeria. The 2D structures of 1 and 2 were defined by NMR analysis, HRESIMS data, and comparison with literature data. The comparison of experimental and calculated electronic circular dichroism and NMR data led to characterization of the ( M) and ( P) atropisomeric forms of the glucopyranosylbianthrones, asphodelins (1) and (2), respectively. The in vitro activities of these two metabolites were evaluated in human melanoma A375 cells, and both the compounds inhibited cell proliferation in a concentration-dependent manner, with IC50 values of 20.6 ± 0.8 and 23.2 ± 1.1 µM, respectively. Considering their biological profile, an inverse virtual screening approach was employed to identify and suggest putative anticancer interacting targets.

Synthesis and in-vitro anticancer evaluation of polyarsenicals related to the marine sponge derived Arsenicin A.

In the light of the promising bioactivity of the tetraarsenic marine metabolite arsenicin A, the dimethyl analogue 2 and four isomeric methylene homologues (including the natural product itself) were obtained using a one-pot microwave-assisted synthesis, starting from arsenic (III) oxide. Due to the poor diagnostic value of the NMR technique in the structural elucidation of these molecules, they were fully characterized by mass spectrometry and infrared (IR)-spectroscopy, comparing density functional theory (DFT) simulated and experimental spectra. This synthetic procedure provided a fast and efficient access to the cytotoxicity evaluation of organoarsenical leads of the natural hit molecule. From in vitro screening, each tested compound resulted in being more active than the FDA-approved arsenic trioxide, with the most lipophilic molecule in the series showing the best growth inhibition of both leukemia and solid tumor cell lines. These results may open promising perspectives in the development of new more potent and selective arsenical drugs against solid tumors.

Iridoids and anti-inflammatory properties of n-butanol extract of Linaria tingitana Boiss. & Reut.

The analysis of the n-butanol extract of Linaria tingitana (BELT) by HPLC-DAD-ESI/MS allowed the identification of four iridoids structurally confirmed by NMR and ESI-MS/MS extensive experiments data. The subjection of BELT to the anti-inflammatory activity showed that it exhibited a concentration dependent stabilisation of HRBC membrane, inhibition of protein denaturation and nitric oxide scavenging effect in the in vitro process. These results were confirmed in the in vivo experiments which showed that BELT was found to be most pronounced at 200 mg/kg after carrageenan injection which significantly reduced the swelling in both early and late phases of carrageenan-evoked oedema, as well as a significant reduce at the accumulation of infiltrating cells, inhibition of the myeloperoxidase activity and suppressed the lipid peroxidation. These results were supported by the histological analysis which revealed the reduction of oedema and cells infiltration, this might be influenced by the synergistic action of the above isolated compounds.

Glycosyl flavonoid profile, in vivo antidiabetic and in vitro antioxidant properties of Linaria reflexa Desf.

Aerial parts of Linaria reflexa, used in North African folk medicine for treating certain skin diseases, were investigated by HPLC-DAD-ESI/MS technique able to identify the glycosyl flavonoids pectolinarin (1), isolinariin A (2), isolinariin B (3), linariin (4), isolinariin D (5) and isolinariin E (6) as the most abundant components in both hydroalcoholic (HAE) and ultrasound-assisted (UAE) extracts profiles. Metabolite 5, isolated and fully characterised by extensive nuclear magnetic resonance (NMR) analysis, has been very recently reported from L. japonica together with the compound 6. Good antioxidant activities (DPPH radical scavenging, ß-carotene bleaching and reducing power assays) were observed for the extracts. The remarkable antidiabetic activity displayed by UAE (300 mg/kg) has yielded the most marked decrease in blood glucose levels of the alloxan diabetic rats (-72.09%), greater than the effects by the drug glybenclamide (-63.29%). This study reports the first correlation of antidiabetic activity of Linaria sp. extracts with their chemical composition.

Chemical constituents and biological activities of the genus Linaria (Scrophulariaceae).

This is a review on 95 references dealing with the genus Linaria (Scrophularioideae-Antirrhineae tribe), a known genus of the Scrophulariaceae family, which comprises about 200 species mainly distributed in Europe, Asia and North Africa. The use of some Linaria species in folk medicine has attracted the attention for chemical and biological studies. This report is aimed to be a comprehensive overview on the isolated or identified known and often new metabolites from the 41 Linaria species so far cited. It is organised presenting first the phytochemical classes of alkaloids, polyphenols including flavonoids, the latter being quite diffused and mostly present as flavones, flavonols and their glycosides, and terpenoids including iridoids and steroids. Second, the results from biological investigation on plant extracts, pure natural products isolated from Linaria species and some synthetic derivatives are reported, with antitumour, anti-acetylcholinesterase, anti-inflammatory and analgesic, antioxidant and antibacterial activities.

p-Sulfonato-calix[n]arenes inhibit staphylococcal bicomponent leukotoxins by supramolecular interactions.

PVL (Panton-Valentine leukocidin) and other Staphylococcus aureus ß-stranded pore-forming toxins are important virulence factors involved in various pathologies that are often necrotizing. The present study characterized leukotoxin inhibition by selected SCns (p-sulfonato-calix[n]arenes): SC4, SC6 and SC8. These chemicals have no toxic effects on human erythrocytes or neutrophils, and some are able to inhibit both the activity of and the cell lysis by leukotoxins in a dose-dependent manner. Depending on the type of leukotoxins and SCns, flow cytometry revealed IC50 values of 6-22 µM for Ca2+ activation and of 2-50 µM for cell lysis. SCns were observed to affect membrane binding of class S proteins responsible for cell specificity. Electrospray MS and surface plasmon resonance established supramolecular interactions (1:1 stoichiometry) between SCns and class S proteins in solution, but not class F proteins. The membrane-binding affinity of S proteins was Kd=0.07-6.2 nM. The binding ability was completely abolished by SCns at different concentrations according to the number of benzenes (30-300 µM; SC8>SC6≫SC4). The inhibitory properties of SCns were also observed in vivo in a rabbit model of PVL-induced endophthalmitis. These calixarenes may represent new therapeutic avenues aimed at minimizing inflammatory reactions and necrosis due to certain virulence factors.

Bioactive poly(arsenic) compounds.

An overview of the biological activities of arsenic compounds containing more than one arsenic atom in their molecular structure is presented. This contribution covers the literature of the last 10-12 years concerning the in vitro and in vivo studies on arsenic species. They include inorganic oxides and sulfides, already employed for a long time in traditional Chinese medicine and currently investigated against hematological or solid malignancies, with arsenic trioxide clinically used in the treatment of acute promyelocytic leukemia. Chemical and biological aspects on the marine product arsenicin A, representing the first and only organic polyarsenical isolated from Nature, have also been reviewed, pointing out the characterization of its C3H6As4O3 molecular structure by experimental and theoretical vibrational spectroscopies, the potent antimicrobial activities, and the promising perspectives as an antitumor agent.