Oral treatments with a flavonoid-enriched fraction from Cecropia hololeuca and with rutin reduce articular pain and inflammation in murine zymosan-induced arthritis

ETHNOPHARMACOLOGICAL RELEVANCE

Cecropia Loefl. species (Urticaceae) are widely spread across the rainforest in tropical and subtropical regions of Central and South America. Inhabitants of different regions of Brazil employ leaves, fruits and sprouts of Cecropia hololeuca Miq. mainly as anti-inflammatory, anti-asthmatic, expectorant, fever suppressant, and against cough.

AIM OF THE STUDY

To evaluate the antinociceptive and anti-inflammatory activities of an aqueous leaf extract of C. hololeuca in a murine model of zymosan-induced arthritis (ZIA) and characterize compounds contributing to these effects.

MATERIALS AND METHODS

The crude aqueous extract of C. hololeuca (CAE) was obtained by infusion, screened for antinociceptive and anti-inflammatory activities, and fractionated (solvent partition; RP-2 and Sephadex G-25 column chromatography), yielding fractions that were chemically and pharmacologically investigated. TLC, HPLC-DAD, HPLC-DAD-ESI-MS/MS and NMR analyses were peformed. The antinociceptive activity was assessed by means of acetic acid-induced writhing, hot-plate and rota-rod tests. ZIA was used to evaluate the anti-arthritic activity of oral treatment with CAE, butanolic (BF) and aqueous fraction (AF), as well as the fractions obtained from BF (F2, F2-A and F2-B). Rutin, a flavonoid found in C. hololeuca, was also tested. Mechanical hypernociception, joint edema, local neutrophil recruitment and articular TNF-α quantification were performed to measure the severity of arthritis and identify the anti-inflammatory potential of C. hololeuca.

RESULTS

CAE (0.03-1 g/kg, p.o.) showed a dose-related inhibitory effect on acetic acid-induced writhing test, but did not change the pain latency in the hotplate test, nor the first fall time on the rota-rod test. In addition, CAE (1 g/kg, p.o.) inhibited by 65% the mechanical hypernociception, 46% the joint edema, 54% the neutrophil recruitment and 53% the articular TNF-α concentration levels in ZIA. BF (0.4 g/kg, p.o.), AF (0.6 g/kg), F2 (0.1 g/kg) and F2-A (0.045 g/kg), but not F2-B (0.055 g/kg), inhibited the mechanical hypernociception, joint edema and neutrophil recruitment in ZIA. Rutin (0.001-0.03 g/kg, p.o.) produced dose-related inhibitory effects in the mechanical hypernociception, joint edema and neutrophil recruitment, and at 0.03 g/kg also inhibited articular TNF-α synthesis after intra-articular zymosan injection. Isoorientin, isovitexin, rutin and isoquercitrin were identified in the most active fraction (F2-A), along with luteolin and apigenin derivatives, tentatively identified as isoorientin-2″-O-glucoside and isovitexin-2″-O-glucoside.

CONCLUSION

This study corroborates the popular use by oral route of aqueous preparations of C. hololeuca against joint inflammatory disorders, such as rheumatoid arthritis. Our results demonstrated for the first time that oral administration of rutin shows antinociceptive and anti-inflammatory effects in ZIA, indicating that this flavonoid is one of the immunomodulatory compounds involved in the anti-arthritic activity of C. hololeuca.

High-frequency electroacupuncture versus carprofen in an incisional pain model in rats

The objective of the present study was to compare the effect of electroacupuncture (EA) and carprofen (CP) on postoperative incisional pain using the plantar incision (PI) model in rats. A 1-cm longitudinal incision was made through skin, fascia and muscles of a hind paw of male Wistar rats and the development of mechanical and thermal hypersensitivity was determined over 4 days using the von Frey and Hargreaves methods, respectively. Based on the experimental treatments received on the third postoperative day, the animals were divided into the following groups: PI+CP (CP, 2 mg/kg, po); PI+EAST36 (100-Hz EA applied bilaterally at the Zusanli point (ST36)); PI+EANP (EA applied to a non-acupoint region); PI+IMMO (immobilization only); PI (vehicle). In the von Frey test, the PI+EAST36 group had higher withdrawal force thresholds in response to mechanical stimuli than the PI, PI+IMMO and PI+EANP groups at several times studied. Furthermore, the PI+EAST36 group showed paw withdrawal thresholds in response to mechanical stimuli that were similar to those of the PI+CP group. In the Hargreaves test, all groups had latencies higher than those observed with PI. The PI+EAST36 group was similar to the PI+IMMO, PI+EANP and PI+CP groups. We conclude that 100-Hz EA at the ST36 point, but not at non-acupoints, can reduce mechanical nociception in the rat model of incisional pain, and its effectiveness is comparable to that of carprofen.

Splenic autotransplantation restores IL-17 production and antibody response to Streptococcus pneumoniae in splenectomized mice

The high incidence of overwhelming postsplenectomy infection caused by Streptococcus pneumoniae can be reduced by splenic autotransplantation. In this study the effect of splenectomy and splenic autotransplantation on the immune response to S. pneumoniae infection was investigated. Balb/c mice were divided into three groups: splenectomized (SP), splenectomized and autotransplanted (AT), and sham operated control (CT). Five days post-infection the serum antibody levels were measured and the number of S. pneumoniae CFU, neutrophil accumulation and IL-17 production in the liver and lungs were investigated. SP mice showed greater number of bacteria in both organs and lower serum levels of S. pneumoniae-specific IgM, IgG1 and IgG2a antibodies. IL-17 production and neutrophil recruitment to the liver and lungs were lower in SP mice, in comparison with both the CT and the AT groups. Levels of S. pneumoniae-specific IgM, CFU counts, neutrophil accumulation and IL-17 production did not differ significantly between the CT and AT groups. These results suggest that splenic autotransplantation restores the capacity of splenectomized mice to fight S. pneumoniae infection.

Staphylococcus aureus infection after splenectomy and splenic autotransplantation in BALB/c mice

Splenectomy results in an increased risk of sepsis. The autogenous transplant of the spleen is an option for preserving splenic functions after total splenectomy. In this study, the capacity of animals undergoing autogenous spleen transplantation to respond to Staphylococcus aureus infection was investigated. BALB/c mice were divided into three groups: splenectomy followed by autotransplantation in the retroperitonium (AT), splenectomized only (SP) and operated non-splenectomized sham control (CT). Thirty days after surgery the mice were infected intravenously with S. aureus. Splenectomized mice had a higher number of colony-forming units (CFU) of S. aureus in liver and lungs in comparison with either AT or with CT mice (P < 0.05). Higher CFU numbers in lung of SP mice correlated with elevated production of interleukin-10 associated with a lower production of interferon-gamma and tumour necrosis factor-alpha. However, systemically, the level of tumour necrosis factor-alpha was higher in the SP group than in CT or AT. Lower titres of specific anti-S. aureus immunoglobulin (Ig)M and IgG1 were observed 6 days after infection in SP mice in comparison either with the AT or CT groups. Thus, splenectomy is detrimental to the immune response of BALB/c mice against infection by S. aureus which can be re-established by autogenous implantation of the spleen.

Performance of bean bruchids Callosobruchus maculatus and Zabrotes subfasciatus (Coleoptera: Bruchidae) reared on resistant (IT81D-1045) and susceptible (Epace 10) Vigna unguiculata seeds: Relationship with trypsin inhibitor and vicilin excretion

Callosobruchus maculatus (Cm) and Zabrotes subfasciatus (Zs) were reared on resistant (IT81D-1045) and on susceptible (Epace 10) cowpea seeds. The emergence of adult insects, total developmental period (TDP) and excretion of trypsin inhibitor and vicilin were determined for both bruchid populations. Parameter evaluation showed that the Zs populations emerged from both seeds had no significant differences in emergence and TDP. The Cm population raised from resistant seeds had lower emergence (5.6+/-1.3%) and delayed TDP (46+/-1.25 days) than those emerged from susceptible seeds. The excretion of defense proteins showed that Zs reared in resistant seeds excreted 1.7 times more trypsin inhibitor, but this did not affect emergence or TDP. Furthermore, Cm population emerged from resistant seeds excreted 7 times higher vicilin and 0.4 times less trypsin inhibitor than that emerged from susceptible seeds. These results indicate that vicilins from resistant seeds are involved to significantly longer TDP (46 days) and also drastic reduction of insect emergence ( approximately 5%) of C. maculatus.

A serine proteinase inhibitor isolated from Tamarindus indica seeds and its effects on the release of human neutrophil elastase

Proteinaceous inhibitors with high inhibitory activities against human neutrophil elastase (HNE) were found in seeds of the Tamarind tree (Tamarindus indica). A serine proteinase inhibitor denoted PG50 was purified using ammonium sulphate and acetone precipitation followed by Sephacryl S-300 and Sephadex G-50 gel filtration chromatographies. Inhibitor PG50 showed a Mr of 14.9 K on Sephadex G-50 calibrated column and a Mr of 11.6 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. PG50 had selective activity while cysteine proteinases (papain and bromelain) and serine proteinases (porcine pancreatic elastase and bovine chymotrypsin) were not inhibited, it was strongly effective against serine proteinases such as bovine trypsin and isolated human neutrophil elastase. The IC50 value was determined to be 55.96 microg.mL-1. PG50 showed neither cytotoxic nor haemolytic activity on human blood cells. After pre-incubation of PG50 with cytochalasin B, the exocytosis of elastase was initiated using PAF and fMLP. PG50 exhibited different inhibition on elastase release by PAF, at 44.6% and on release by fMLP, at 28.4%. These results showed that PG50 preferentially affected elastase release by PAF stimuli and this may indicate selective inhibition on PAF receptors.

Immunomodulatory activity of Mollugo verticillata L

This article describes the evaluation of immunomodulatory activity of Mollugo verticillata L. (Molluginaceae), a weed plant common in warm and/or wet regions of the American continent. Nitric oxide (NO) release was evaluated in mice peritoneal cell cultures treated in vivo using the ethanolic extract of M. verticillata with and without BCG. The plant extract showed immunostimulatory activity when peritoneal cells were stimulated in vitro with BCG antigen only. However, mice peritoneal cells treated with M. verticillata plus BCG showed a drastic reduction in NO production when they received the additional stimulus in vitro with BCG. Ethanolic extracts of M. verticillata could directly increase NO release by peritoneal cells, but suppress the immune response of these cells when treated with BCG antigen and Mycobacterium tuberculosis whole antigen (TB). Preliminary phytochemical tests allowed the detection of quercetin and triterpenoid glycosides in the ethanolic extract of M. verticillata, and those compounds are probably responsible for the effect of this plant material on the immune system.