Morphogenesis and in vitro production of caffeoylquinic and caffeic acids in Baccharis conferta Kunth

We established a protocol for the in vitro propagation of Baccharis conferta Kunth. This plant is used to treat gastrointestinal problems, cramps, pain, respiratory problems, and insect bites. A high rate of shoot multiplication was obtained from nodal segments on Murashige and Skoog (MS) culture medium. The shoots regenerated roots without exogenous plant growth regulators (PGRs). All explants of wild leaves on MS medium containing 5 μM of thidiazuron (TDZ) produced friable callus. An organogenic response was achieved after 3 wk of culture when callus segments were transferred to MS medium containing a combination of plant growth regulators (PGRs): either (i) 5 μM indole butyric acid (IBA) + 5 μM kinetin (KIN) or (ii) 0.5 μM IBA + 1.10 μM benzylaminopurine (BAP). The morphogenetic responses of callus were characterized by scanning electron microscopy. Shoots regenerated from callus and formed roots on MS medium without PGRs. The micropropagated plantlets and the organogenic callus showed similar chemical profiles in HPLC-mass spectrometry analyses. The main compounds present in the cultures were caffeoylquinic acids. Only plantlets contained small amounts of triterpenes (erythrodiol and ursolic acid). These findings will be useful for the micropropagation of this important native resource, and for further studies on its biology.

     

Synthesis and Cytotoxicity Studies of Br-Substituted Salphen Organic Compounds

We present the synthesis and characterization of organic Salphen compounds containing bromine substituents at the para/ortho-para positions, in their symmetric and non-symmetric versions, and describe the X-ray structure and full characterization for the new unsymmetrical varieties. We report for the first time antiproliferative activity in metal-free brominated Salphen compounds, by evaluations in four human cancer cell lines, cervix (HeLa), prostate (PC-3), lung (A549) and colon (LS 180) and one non-cancerous counterpart (ARPE-19). We assessed in vitro cell viability against controls using the MTT assay ((3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide)) and determined the concentration required for 50 % growth inhibition (IC₅₀), together with their selectivity vs. non-cancerous cells. We found promising results against prostate (9.6 μM) and colon (13.5 μM) adenocarcinoma cells. We also found a tradeoff between selectivity (up to 3-fold vs. ARPE-19) and inhibition, depending upon the symmetry and bromine-substitution of the molecules, showing up to 20-fold higher selectivity vs. doxorubicin controls.