Epanorin, a lichen secondary metabolite, inhibits proliferation of MCF-7 breast cancer cells

BACKGROUND: Epanorin (EP) is a secondary metabolite of the Acarospora lichenic species. EP has been found in lichenic extracts with antimicrobial activity, and UV-absorption properties have been described for closely related molecules; however, its antiproliferative activity in cancer cells has not yet been explored. It has been hypothesized that EP inhibits cancer cell growth. MCF-7 breast cancer cells, normal fibroblasts, and the non-transformed HEK-293 cell line were exposed to increasing concentrations of EP, and proliferation was assessed by the sulforhodamine-B assay. RESULTS: MCF-7 cells exposed to EP were examined for cell cycle progression using flow cytometry, and DNA fragmentation was examined using the TUNEL assay. In addition, EP's mutagenic activity was assessed using the Salmonella typhimurium reverse mutation assay. The data showed that EP inhibits proliferation of MCF-7 cells, and it induces cell cycle arrest in G0/G1 through a DNA fragmentation-independent mechanism. Furthermore, EP's lack of overt cytotoxicity in the normal cell line HEK-293 and human fibroblasts in cell culture is supported by the absence of mutagenic activity of EP. CONCLUSION: EP emerges as a suitable molecule for further studies as a potential antineoplastic agent.

Actividad antibacteriana in vitro de la depsidona clorada 1'-cloropannarina / In vitro antibacterial activity of chlorinated depsidone, 1'-chloropannarina

Mediante el método de dilución en tubo, se determinó la concentración inhibitoria mínima (CIM) de la 1'-cloropannarina, depsidona clorada aislada de líquenes, en 75 cepas de bacterias gram-positivas y 27 cepas de hongos patógenos y oportunistas, Streptococcus pneumoniae y Mycrococcus luteus presentaron los menores valores de CIM, 0.39µg ml-1. Para Staphylococcus aureus y S. epidermidis se obtuvieron CIM de 2.80 y 2.74µg ml-1. La constante específica de inhibición de la droga (Kc) obtenida de curvas de generación de Staphylococcus aureus ATCC 3598, fue de 4.5 x 10-5 min-1 ml µg-1. La 1'-cloropannarina mayor actividad antibacteriana que la eritromicina y la penicilina frente a Staphylococcus epidermidis. La CIM para hongos flucturaron entre 35.0 y 58.6 µg ml-1; para Candida albicans el valor obtenido fue de 40µml-1