Antiproliferative activity, antioxidant capacity and chemical composition of extracts from the leaves and stem of Chresta sphaerocephala

AbstractIn this study, antiproliferative and antioxidant activities of crude extracts (hexane, ethyl acetate and methanol) from leaves and stem of Chresta sphaerocephala DC., Asteraceae, were investigated. Antiproliferative activity was tested in vitro against ten human cancer cells and against VERO (no cancer cell). Antioxidant activities were determined using DPPH and ORAC-FL assays and the total phenolic content was estimated by Folin–Ciocalteu method. Hexane and ethyl acetate extracts (leaves and stem) exhibited antiproliferative activity against cancer cell lines with total growth inhibition (TGI) between 50.40 and 250 µg/ml. For VERO cell, TGI values were >250 µg/ml for all extracts, except to hexane extract of the stem (TGI 80.92 µg/ml). In an initial evaluation, ethyl acetate and methanol extracts (leaves and stem) have shown levels of phenolic compounds between 6.94 and 30.96 mg GAE/kg in Folin–Ciocalteu assay, DPPH free-radical scavenging activity with SC50 in the range of 75.22 and 400 µg/ml and antioxidant capacity between 290.08 and 1088 µmol TE/g of extract in ORAC-FL assay. HPLC-DAD and ESI-MS analysis allowed the identification of flavonoids in the methanol extract from the leaves of C. sphaerocephala. Three steroids and nine triterpenoids were identified in the bioactive hexane extracts using HRGC.

Comparative study of the effect of green and roasted water extracts of mate (Ilex paraguariensis) on glucosyltransferase activity of Streptococcus mutans.

Glucosyltransferase (GTF) plays an important role in the development of dental caries. This study was carried out to compare the efficiency of green mate (GM) and roasted mate (RM) water extracts, drinks rich in polyphenolic compounds consumed in the subtropical region of South America, on the extracellular GTF activity from Streptococcus mutans. The RM extract exhibited a greater inhibitory effect (IC50 of 10 mg/mL) despite presenting lower polyphenolic content. The kinetic analysis showed that there were significant differences (P < 0.05) between the extracts with respect to the values for K(m) and K(i), whereas the values for V(max) were the same, implying the competitive nature of GTF inhibition. GTF activity was also measured using selected polyphenols as inhibitors, and the most effective inhibitors were rutin and caffeoylshikimic acid. The characterization of the extracts by ESI-MS and UPLC-MS showed that the compounds formed during roasting, possibly shikimic acid derivatives and other unindentified compounds formed by the Maillard reaction, appeared to contribute to the inhibition of GTF activity.

Analysis of the hepatoprotective activity and the toxicological, chemical and physical-chemical profiles of a sample of Brazilian propolis

In the present assay, the hepatoprotective activity of a sample of propolis from Rio Azul (PR) BRazil was studied using the model of acute hepatotoxicity induced by carbon tetrachloride (CCl4). The physical-chemical, chemical and toxicological profiles of the sample were also studied. The chemical analyses of the sample indicated the presence of gallic acid derivatives, 3-methoxy-4-hydroxy cinnamaldehyde as well as other unidentified compounds....