Evaluation of the mutagenic activity of chrysin, a flavonoid inhibitor of the aromatization process

Chrysin is one of the natural flavonoids present in plants, and large amounts are present in honey and propolis. In addition to anticancer, antioxidation, and anti-inflammatory activities, chrysin has also been reported to be an inhibitor of aromatase, an enzyme converting testosterone into estrogen. The present study evaluated the mutagenicity of this flavonoid using micronucleus (MN) with HepG2 cells and Salmonella. Cell survival after exposure to different concentrations of chrysin was also determined using sulforhodamine B (SRB) colorimetric assay in HepG2 cells and the influence of this flavonoid on growth of cells in relation to the cell cycle and apoptosis. The MN test showed that from 1 to 15 μM of this flavonoid mutagenic activity was noted in HepG2 cells. The Salmonella assay demonstrated a positive response to the TA100 Salmonella strain in the presence or absence of S9, suggesting that this compound acted on DNA, inducing base pair substitution before or after metabolism via cytochrome P-450. The SRB assay illustrated that chrysin promoted growth inhibition of HepG2 cells in both periods studied (24 and 48 h). After 24 h of exposure it was noted that the most significant results were obtained with a concentration of 50 μM, resulting in 83% inhibition and SubG0 percentage of 12%. After 48 h of incubation cell proliferation inhibition rates (97% at 50 μM) were significantly higher. Our results showed that chrysin is a mutagenic and cytotoxic compound in cultured human HepG2 cells and Salmonella typhimurium. Although it is widely accepted that flavonoids are substances beneficial to health, one must evaluate the risk versus benefit relationship and concentrations of these substances to which an individual may be exposed.

Lafoensia pacari extract inhibits IL-5 production in toxocariasis

Toxocariasis is an infection induced by Toxocara canis, an intestinal parasite of dogs. In this study, an experimental murine model of toxocariasis was used to evaluate the anti-inflammatory activity of an ethanolic extract of Lafoensia pacari stem bark. Mice infected with T. canis were treated with L. pacari extract (200 mg/kg, p.o.). Subsequently, we observed a reduction in the number of eosinophils in the peritoneal cavity, bronchoalveolar fluid, blood and bone marrow. Production of interleukin (IL)-5, a major cytokine involved in eosinophilic differentiation, proliferation and activation, is also an important marker for infection. The reduced levels of IL-5 observed in serum, lung homogenates and bronchoalveolar fluid demonstrated the anti-inflammatory mechanisms of L. pacari. Larvae recovery from infected mice treated with L. pacari was comparable with that from untreated mice, suggesting that L. pacari is not toxic to the parasite. Nonetheless, our results demonstrate a potential therapeutic effect of L. pacari extract in IL-5-mediated inflammatory diseases and provide new prospects for the development of drugs to treat IL-5-dependent allergic diseases such as parasite infection and asthma.

[Endomyocardial fibrosis: surgical treatment]

The authors analyse the experience acquired for surgical treatment of endomyocardiofibrosis. Among the 15 patients submitted to the operation, nine had the biventricular form, four had the disease in the right ventricle and two only in the left ventricle. The surgery consisted of endocardioectomy of the ventricles (RV--04,LV--02, bilateral--08) and replacement of the diseased atrioventricular valves (mitral--02, tricuspid--06, mitral and tricuspid--07). In one patient there was severe obstruction of the anterior descending artery and a bypass was done. Three patients had associated rheumatic mitral stenosis. There was one early operative death and three late deaths (respectively 13.34 and 37 months later). Two patients required re-operation. The first one, 33 months later, to replace the mitral valve which had been preserved in the first procedure, and the second, 12 months later, who presented ventricular septal defect secondary to rupture of the weak septum. Of all the patients who underwent surgery, 11 survived and all, except one, have had a good course. The detailed analysis of this series permitted us to conclude that: 1st--the general use of the bidimensional echocardiography in high risk patients, allows early diagnosis in a greater number of them; 2nd, the surgery must be early to avoid cardiac and extracardiac injury due to the disease; 3rd--a low profile valve must be used; 4th--to this moment there have been no signs of recurrence; 5th--surgical treatment appears to improve the course of this terrible disease.