Renata M. Araújo

Antioxidant and anti-inflammatory effect of polysaccharides from Lobophora variegata on zymosan-induced arthritis in rats

This study analyzes the action of sulfated polysaccharides, fucans, from algae Lobophora variegata on zymosan-induced arthritis in rats. Groups of fucans, obtained after acetone fractionation (0.3-2.0 volumes), were denominated F0.3, F0.5, F0.8, F1, F1.5, and F2. The results that F1 contained a high yield in relation to other fractionated fucans. Chemical and structure analysis of F1 was performed by nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies. The in vitro antioxidant activities of the fraction F1 were also observed. Thus, 2 mg/mL of F1 inhibited the phosphomolybdate in the total antioxidant activity assay. The EC(50) values were 0.3 mg/mL and 0.12 mg/mL for superoxide and hydroxyl radicals, respectively. Fucan F1 (25, 50, and 75 mg/kg by body weight), diclofenac sodium (10 mg/kg), and L-NAME (25 mg/kg) were administered intraperitoneally (i.p.) in rats, according to body weight of different groups of animals (n=6). After 6 h, analyses of cell influx and nitrite levels were conducted. Then after 96 h, analysis of edema and concentration of serum TNF-α was carried out along with histopathological analysis. F1 at 25, 50, and 75 mg/kg i.p. by body weight reduced cell influx in 52.1-96.7% and nitric oxide level in 27.2-39% compared with the control group. The reduction of edema and serum TNF-α was observed at 50 mg/kg i.p. (p<0.001). These results suggest that this heterofucan from the brown algae L. variegata has potential anti-inflammatory activity in acute zymosan-induced arthritis in rats and that antioxidant activity promotes modulation in the cellular redox state.

Glucans from the Caripia montagnei mushroom present anti-inflammatory activity.

Caripia montagnei is a basidiomycete species which contains polysaccharides with immunomodulatory properties. An extract of this mushroom underwent removal of the fat content by organic solvent and subsequently proteolysis. The aqueous phase obtained after proteolysis was precipitated with methanol yielding a fraction containing carbohydrates (98.7+/-3.3%) and protein (1.3+/-0.25%). Chemical analysis, infrared spectroscopy and nuclear magnetic resonance (NMR) showed that the carbohydrate fraction contained (63.3+/-4.1) of beta-glucans and proteins (2.2+/-0.3%). These glucans (50mg/kg of body weight) significantly reduced the inflammatory infiltrate produced by thioglycolate-induced peritonitis by 75.5+/-5.2%, when compared to Wy-14643 (60.3+/-6.1%), PFOA (37.8+/-2.8%) and clofibrate (52.2+/-3.2%), p<0.001, which are of the peroxisome proliferator-activated receptor (PPAR-alpha). L-NAME, a nitric oxide synthase inhibitor, reduced the plantar edema in Wistar rats by 91.4+/-1.3% (p<0.001). A significant reduction in nitric oxide (NO) levels was observed in the exudates when the glucans was used in comparison to carrageenan. The C. montagnei glucans did not present signs of inducing cytotoxicity. A decrease in IL-1ra, IL-10 and IFN-gamma in the peritonitis model was observed. Thus, the results suggest that glucans from the C. montagnei mushroom is an effective immunomodulator and may have potential for anti-inflammatory properties.

Discovery of the rapanone and suberonone mixture as a motif for leishmanicidal and antifungal applications.

Leishmaniasis and fungal infections are significant diseases impacting worldwide public health. Treatments have developed greatly over time, however, there is a necessity to discover less toxic drugs, which have greater efficacy and are more economically accessible. This work conducted a screening of Cerrado species extracts: Connarus suberosus Planch. (Connaraceae), Neea theifera Oerst. (Nyctaginaceae) and Myrcia linearifolia Cambess. (Myrtaceae) against Leishmania (Leishmania) amazonensis, dermatophytes and yeasts. Leishmanicidal and antifungal tests were conducted using MTT colorimetric assay and CLSI methodology, respectively. Connarus suberosus extracts presented the most promising results against the aforementioned microorganisms, which has not been described in the literature. The root bark EtOAc extract was selected for chemical fractionation resulting in a mixture of rapanone (1) and a previously unreported compound named as suberonone (2); a mixture of β-sitosterol (3) and stigmasterol (4); oleic acid (5); geranilgeraniol (6); and two derivatives obtained from 1 and 2 mixture. The rapanone and suberonone mixture demonstrated a MIC of 15.62 μg/mL against Candida albicans ATCC 10231.

Chemical characteristics of a heteropolysaccharide from Tylopilus ballouii mushroom and its antioxidant and anti-inflammatory activities.

Fucogalactomannan (FGM) is a non-sulphated polysaccharide isolated from the Tylopilus ballouii mushroom. We investigated the chemical characteristics of this FGM using HPLC, chemical methods, and NMR studies ((1)H, (13)C, (1)H/(13)C-HSQC and DEPT-135 spectroscopies) without chemical fragmentation. This polysaccharide consisted primarily of mannose and galactose with variable amounts of fucose and traces of xylose and with MW of 140kDa. Infrared and NMR spectroscopies showed the possible interaction between these polysaccharides and proteins. The antioxidant activity showed for FGM a high inhibition of superoxide and hydroxyl radicals with an IC50 of 1.25 and 1.6mg/mL, respectively. The results of peroxidation tests showed that FGM had an IC50 of 1.72mg/mL. Furthermore, the anti-inflammatory assay showed that FGM reduced edema by 32.8%, 42.0%, and 56% at doses of 30, 50, and 70mg/kg, respectively. Thus, these results suggested a structure and indicated possible anti-inflammatory and antioxidant activities use of these polysaccharides.

Quantification of Synthetic Amino-Nitroquinoxaline Dyes: An Approach Using Image Analysis

This paper describes the use of digital imaging acquired from a conventional desktop scanner for characterization of newly synthesized amino-nitroquinoxaline dyes. The synthetic protocol was based on reactions of building block 2,3-dichloro-6,7-dinitroquinoxaline with aliphatic amines and experiments based on image analysis were carried out with compounds in solution (96-microwell plates) and/or adsorbed on silica (thin-layer chromatography (TLC) plates). Three main goals were achieved: firstly, compounds 2-chloro-6,7-dinitro-3-pyrrolidinoquinoxaline and 6,7-dinitro-2,3-dipyrrolidinoquinoxaline had their concentration predicted in dimethyl sulfoxide (DMSO) solution, as a mixture. Secondly, TLC studies were performed to build a kinetic profile in attempt to monitor reaction involving conversion of 2-chloro-6,7-dinitro-3-pyrrolidinoquinoxaline into 6,7-dinitro-2,3-dipyrrolidinoquinoxaline. Lastly, image analysis and UV-Vis spectroscopy were applied to study the interaction of 2,3-di-n-butylamino-6,7-dinitroquinoxaline with hydroxide anion in DMSO. These approaches based on digital image characterization were successfully implemented in qualitative and quantitative analysis of organic dyes.