Towards effective natural anthraquinones to mediate antimicrobial photodynamic therapy of cutaneous leishmaniasis.

Background: Cutaneous leishmaniasis (CL) is an important tropical neglected disease with broad geographical dispersion. The lack of effective drugs has raised an urgent need to improve CL treatment, and antimicrobial photodynamic therapy (APDT) has been investigated as a new strategy to face it with positive outcomes. Natural compounds have emerged as promising photosensitizers (PSs), but their use in vivo remains unexplored.

New insights into the antiviral activity of nordihydroguaiaretic acid: Inhibition of dengue virus serotype 1 replication.

Background: Dengue virus (DENV) is considered one of the most important pathogens in the world causing 390 million infections each year. Currently, the development of vaccines against DENV presents some shortcomings and there is no antiviral therapy available for its infection. An important challenge is that both treatments and vaccines must be effective against all four DENV serotypes.

Photosensitization Induced by in Goats: Sequential Development of Skin Lesions.

Five adult Saanen goats received a single oral dose of containing 42.25 μg/kg rubiadin (anthraquinone) and 3 adult goats were untreated controls. All goats were exposed to sunlight and sequential ear skin biopsies were collected before treatment and at 32 hours, 3 days, 8 days, and 15 days after treatment.

Inactivation of Herpes Simplex Virus by Photosensitizing Anthraquinones Isolated from Heterophyllaea pustulata.

is a phototoxic plant from Argentina. Aerial parts extracts, high in photosensitizing anthraquinones, have shown antiviral activity. The purpose of this study was to study the antiherpetic activity of the main purified anthraquinones, even evaluating their competence as photodynamic sensitizers to photo-stimulate the antiviral effect.

First report of antiviral activity of nordihydroguaiaretic acid against Fort Sherman virus (Orthobunyavirus).

The genus Orthobunyavirus are a group of viruses within arbovirus, with a zoonotic cycle, some of which could lead to human infection. A characteristic of these viruses is their lack of antiviral treatment or vaccine for its prevention. The objective of this work was to study the in vitro antiviral activity of nordihydroguaiaretic acid (NDGA), the most important active compound of Larrea divaricata Cav.

Natural photosensitizers in photodynamic therapy: In vitro activity against monolayers and spheroids of human colorectal adenocarcinoma SW480 cells.

Photodynamic Therapy (PDT), is a treatment option for cancer.It involves the photochemical interaction of light, photosensitizer (PS) and molecular oxygen to produce radical species as well as singlet oxygen which induce cell death. Anthraquinones (AQs) have been extensively studied with respect to their UV/Vis absorption characteristics and their photosensitizing properties in photodynamic reactions.

Natural anthraquinones as novel photosentizers for antiparasitic photodynamic inactivation.

Background: Cutaneous leishmaniasis (CL) is a vector-borne disease caused by obligate protist parasites from the genus Leishmania. The potential toxicity as well as the increased resistance of standard treatments has encouraged the development of new therapeutical strategies. Photodynamic inactivation (PDI) combines the use of a photosensitizer and light to generate reactive oxygen species and kill cells, including microorganisms.

Experimental poisoning by Heterophyllaea pustulata Hook. f. (Rubiaceae) in goats. Clinical, biochemical and toxicological aspects.

The aim of this study was to investigate the clinical, biochemical and toxicological findings of the experimentally poisoning induced by Heterophyllaea pustulata in goats. Ten healthy adult female Saanen breed goats were used in the experiment. The goats were randomly assigned to two groups of five individuals: control and experimental group (CG and EG).

On the mechanism of Candida tropicalis biofilm reduction by the combined action of naturally-occurring anthraquinones and blue light.

The photoprocesses involved in the photo-induced Candida tropicalis biofilm reduction by two natural anthraquinones (AQs), rubiadin (1) and rubiadin-1-methyl ether (2), were examined. Production of singlet oxygen (1O2) and of superoxide radical anion (O2•-) was studied. Although it was not possible to detect the triplet state absorption of any AQs in biofilms, observation of 1O2 phosphorescence incubated with deuterated Phosphate Buffer Solution, indicated that this species is actually formed in biofilms.

Photosensitizing anthraquinones from Heterophyllaea lycioides (Rubiaceae).

Seven anthraquinones were isolated from aerial parts of Heterophyllaea lycioides (Rusby) Sandwith (Rubiaceae), including three derivatives that have not been described before: a hetero-bianthraquinone identified as (R)-2-hydroxymethyl-2'methyl-1,1',6,6'-tetrahydroxy-5,5' bianthraquinone (lycionine), and two mono-chlorinated derivatives related to soranjidiol. One of them is a homo-bianthraquinone: (R)-7-chloro-2,2'-dimethyl-1,1',6,6'-tetrahydroxy-5,5' bianthraquinone (7-chlorobisoranjidiol), whereas the second halogenated derivative corresponds to a monomeric structure: 5-chloro-1,6-dihydroxy-2-methyl anthraquinone (5-chlorosoranjidiol). The four known compounds were already isolated from another species of this genus, H.

Parietin: an efficient photo-screening pigment in vivo with good photosensitizing and photodynamic antibacterial effects in vitro.

The photophysical, photoinduced pro-oxidant and antibacterial properties in vitro of the natural occurring parietin (PTN; 1,8-dihydroxy-3-methoxy-6-methyl-9,10-anthraquinone) were evaluated. PTN was extracted from the lichen identified as Teloschistes flavicans (Sw.) Norm.

The anthraquinones rubiadin and its 1-methyl ether isolated from Heterophyllaea pustulata reduces Candida tropicalis biofilms formation.

Background: Candida tropicalis is increasingly becoming among the most commonly isolated pathogens causing fungal infections with an important biofilm-forming capacity.

Purpose: This study addresses the antifungal effect of rubiadin (AQ1) and rubiadin 1-methyl ether (AQ2), two photosensitizing anthraquinones (AQs) isolated from Heterophyllaea pustulata, against C. tropicalis biofilms, by studying the cellular stress and antioxidant response in two experimental conditions: darkness and irradiation.

Reduction of Candida tropicalis biofilm by photoactivation of a Heterophyllaea pustulata extract.

Context: Biofilm formation is an important problem, since this growth mode confers resistance to drugs usually used in therapeutics.

Objective: In vitro antifungal activity of extracts obtained from Heterophyllaea pustulata Hook f. (Rubiaceae) were studied against Candida tropicalis biofilms, evaluating the effect of irradiation and the oxidative and nitrosative stresses as possible mechanisms of action.

In vitro antiviral activity of Heterophyllaea pustulata extracts.

The antiviral activity was tested of different polarity extracts, with differing chemical composition, obtained from aerial parts of Heterophyllaea pustulata Hook f. (Rubiaceae) against Herpes Simplex Virus Type I (HSV-1) and Saint Louis Encephalitis Virus (SLEV). The Vero cell line was employed as a host cell for the antiviral assessment of benzene (Ben), ethyl acetate (EtOAc) and ethanol (EtOH) extracts by means of the Neutral Red uptake assay and plaque reduction test.

Phototoxic effects of Heterophyllaea pustulata (Rubiaceae).

Heterophyllaea pustulata (Rubiaceae), a South American genus, is a phototoxic shrub that grows in the Andean mountain range of the northwest of Argentina, popularly known as "cegadera". Animals that ingest the aerial parts of this plant suffer a typical primary photosensitization reaction, clinically revealed by dermatitis and blindness in severe cases. Anthraquinone derivatives (AQs), the main metabolites of this species, are characterized as Type I and/or Type II photosensitizers according to their physicochemical properties.

Anthraquinone derivatives from Heterophyllaea pustulata.

From the leaves of Heterophyllaea pustulata two new monomeric anthraquinones, heterophylline (1,6-dihydroxy-7-methoxy-2-methylanthraquinone, 1) and pustuline (2-hydroxy-3-methoxy-7-methylanthraquinone, 2), and one new bianthraquinone, (S)-5,5'-bisoranjidiol [(S)-5,5'-bis(1,6-dihydroxy-2-methylanthraquinone), 3], were isolated. Furthermore, the iridoid glycoside asperuloside and three known flavonoids, quercetin, isoquercitrin, and quercetin-3-O-beta-d-glucosyl-6' '-acetate, were obtained. The structures were determined by analysis of their spectroscopic data and chemical evidence.

Inhibitory effects of sulphated flavonoids isolated from Flaveria bidentis on platelet aggregation.

Flaveria bidentis is a plant species that has as major constituents sulphated flavonoids in the highest degree of sulphatation. Among them, quercetin 3,7,3',4'-tetrasulphate (QTS) and quercetin 3-acetyl-7,3',4'-trisulphate (ATS) are the most important constituents. Both showed anticoagulant properties.

Natural anthraquinones probed as Type I and Type II photosensitizers: singlet oxygen and superoxide anion production.

The photosensitizing properties of six anthraquinones (AQs): soranjidiol (1), soranjidiol-1-methyl ether (2), rubiadin (3), rubiadin-1-methyl ether (4), damnacanthal (5) and damnacanthol (6), isolated from leaves and stems of Heterophyllaea pustulata Hook. f. (Rubiaceae) were studied.

Anticoagulant effect and action mechanism of sulphated flavonoids from Flaveria bidentis.

Quercetin 3-acetyl-7,3',4'-trisulphate (ATS) and quercetin 3,7,3',4'-tetrasulphate (QTS) obtained from Flaveria bidentis (Asteraceae) were investigated in vitro for anticoagulant activity. Three different concentrations of each flavonoid were assayed at different incubation times, showing at 1 mM significant prolongation on the activated partial thromboplastin time (APTT), less on the prothrombin time (PT), and no effect on the thrombin time (TT). In order to define the action mechanism of the anticoagulant activity, all coagulation factors were evaluated and no important activity decrease was observed, indicating that another mechanism is involved.