Antigenotoxic, and anticytotoxic activities of an ethanolic extract of Lafoensia pacari (Lythraceae) stem bark in bacteria and mice.

Lafoensia pacari (Lythraceae), popularly known in Brazil as "pacari", is a small tree native to the Cerrado that is used in folk medicine to treat cancer and as an anti-inflammatory and cicatrizing agent. We evaluated the genotoxic, cytotoxic, antigenotoxic, and anticytotoxic activities of an ethanol extract of L. pacari stem bark (EESB) using the Ames test and the mouse bone marrow micronucleus test. In the Ames test, EESB did not significantly increase the number of His(+) revertants in Salmonella typhimurium tester strains TA98 and TA100 at all doses, demonstrating lack of mutagenicity. Only the highest dose of EESB significantly increased the micronucleated polychromatic erythrocyte frequency in the micronucleus test, indicating mild genotoxicity. EESB produced a mutagenic index lower than the negative control in the Ames test. In the micronucleus test, at all doses, EESB caused a significant decrease in the polychromatic/normochromatic erythrocyte ratio (PCE/NCE) at 24 h compared with the negative control. EESB co-administered together with the respective positive control caused a significant decrease in the number of His(+) revertant colonies in the Ames test and in the frequency of micronucleated polychromatic erythrocytes in the micronucleus test, demonstrating a DNA protector effect. EESB co-administered with mitomycin C significantly increased the PCE/NCE ratio at all doses, showing an anticytotoxic effect. We conclude that EESB has antigenotoxic and anticytotoxic properties.

Modulatory effects of Duguetia furfuracea (A. St. Hil) Benth. and Hook. f. in Drosophila melanogaster somatic and germinative cells.

Mutagenic and antimutagenic activities of the medicinal plant Duguetia furfuracea were assessed using SMART/wing and ring-X-loss tests. For the ring-X-loss test, 2- to 3-day-old Drosophila melanogaster ring-X-lineage males and virgin ywsn³ females received D. furfuracea infusion at doses of 0.085, 0.042, or 0.014 g/mL for 24 h. We found that D. furfuracea did not produce any mutagenic effects in D. melanogaster germinative cells. The somatic cells of D. melanogaster were analyzed using the SMART/wing test involving three lineages - mwh, flr³, and ORR - and the same doses of D. furfuracea infusion employed in the ring-X-loss test, as well as 20 mM urethane. The results of both standard (ST) and high bioactivation (HB) crosses showed absence of mutagenic activity of D. furfuracea. In contrast, in both ST and HB crosses, we observed a modulatory effect of D. furfuracea against the genotoxic activity of urethane.

Mutagenic potential and modulatory effects of the medicinal plant Luehea divaricata (Malvaceae) in somatic cells of Drosophila melanogaster: SMART/wing.

Luehea divaricata is a native plant of the Brazilian Cerrado, known as "açoita-cavalo". It is used as a popular herbal medicine in the treatment of dysentery, bleeding, arthritis, tumors, ulcers, and gangrenous wounds. Considering that herbal medicines sometimes provoke tumors and/or may prevent mutational events, it is important to study the action of these natural drugs on DNA. Aqueous extract of the bark of L. divaricata was evaluated at three different concentrations (0.10, 0.30, 0.50 mg/mL), individually and in combination with the neoplastic drug doxorubicin (DXR), by the somatic mutation and recombination test (SMART/wing) in Drosophila melanogaster. Distilled water was included as a negative control. The mutation frequency in the treatments with L. divaricata extract alone was not significantly higher than in the negative control for standard (ST) and high bioactivation (HB) crosses. When L. divaricata extract was combined with DXR, there was a significant reduction in the frequency of spots when compared to DXR alone, in both crosses. Further studies with other experimental models would be useful to confirm that L. divaricata extract is not harmful and that it could be used in the prevention of cancer.