Effect of ethyl acetate extract of usnea longissima on esophagogastric adenocarcinoma in rats

Abstract Purpose: To investigate the effects of the EtOAc extract of U. longissima which is uninvestigated previously on esophagogastric cancer induced in rats with N-methyl-N-nitro-N-nitrosoguanidin (MNNG). Methods: The anticancer activity of EtOAc extract of U. longissima was examined in the esophagogastric adenocarcinoma models induced in rats with MNNG. EtOAc extract of U. longissima, 50 and 100 mg/kg oral doses were administered once daily for six months. MNNG induced differentiated and undifferentiated type adenocarcinomas in the esophageal and gastric tissues of rats. Results: EtOAc extract of U. longissima obtained from U. longissima prevented gastric and esophageal cancerogenesis induced in rats with MNNG. EtOAc extract of U. longissima did not have a lethal effect at doses of 500, 1000 and 2000 mg/kg. The prominent anticarcinogenic activity of EtOAc extract of U. longissima 50 and 100 mg/kg suggests that it is not toxic and it is selective to the cancer tissue. Conclusion: This information may shed light on clinical implementation of EtOAc extract of U. longissima in future.

Evaluación de la actividad antifúngica del extracto de Usnea laevis en hongos fitopatógenos / Evaluation of the antifungal activity of the lichenic extract of Usnea laevis in phytopathogenic fungi

Los líquenes son producto de una asociación simbiótica entre un hongo y alga y/o cianobacteria; esta simbiosis produce una serie de metabolitos secundarios o sustancias liquénicas únicas, las mismas que son aisladas a partir de sus extractos y que han presentado una marcada actividad antibiótica y antifúngica. Considerando que en el Ecuador no se tienen antecedentes acerca de este tipo de estudios, el objetivo planteado fue el evaluar la actividad antifúngica del extracto liquénico de Usnea laevis frente a hongos fitopatógenos. En el presente estudio las sustancias liquénicas almacenadas en el talo de Usnea laevis fueron extraídas con metanol y etanol. La actividad antifúngica in vitro de estos extractos fue probado frente a géneros de hongos fitopatógenos previamente aislados (Aspergillus, Penicillium y Rhizopus stolonifer); añadiéndolo al medio de cultivo Agar Papa Dextrosa (PDA) a una concentración de 0,5%; determinándose el porcentaje de inhibición. Los datos fueron analizados estadísticamente y se realizó la clasificación del extracto en base a su porcentaje de inhibición según la OILB. El extracto metanólico y etanólico de Usnea laevis mostró una mayor efectividad frente a Rhizopus stolonifer, inhibiendo más del 50% de su crecimiento, a diferencia de Penicillium y Aspergillus cuyo porcentaje de inhibición fue mucho menor y mostraron diferencias estadísticamente significativas. El extracto liquénico fue moderadamente tóxico para Rhizopus stolonifer, ligeramente tóxico para Aspergillus sp 1 y Penicillium sp e inocuo para Aspergillus sp 2.

A lichen is an organism product of a symbiotic association between a fungus and algae and / or cyanobacteria; this symbiosis produces many secondary metabolites or unique lichen substances, which are isolated from their extracts and show a marked antibiotic and antifungal activity. Considering there is no background on this type of studies in Ecuador, the aim of this study was to evaluate the antifungal in vitro activity of Usnea laevis extract on phytopathogenic fungi. The lichenic substances stored in the thallus of Usnea laevis were extracted with methanol and ethanol. The in vitro antifungal activity of these extracts was tested against phytopathogenic fungal genera previously isolated (Aspergillus, Penicillium and Rhizopus stolonifer) . They were adding to Potato Dextrose Agar (PDA) culture medium at a concentration of 0.5%, and the inhibition percentage was determined. Data were statistically analyzed and the extract was classified based on its inhibition percentage according to the OILB. Methanolic and ethanolic extracts of Usnea laevis showed greater effectiveness against Rhizopus stolonifer, inhibiting more than 50% of its growth, unlike Penicillium and Aspergillus, whose inhibition percentage was lower and showed significant differences. The liquid extract was also moderately toxic to Rhizopus stolonifer, slightly toxic to Aspergillus sp 1 and Penicillium sp and harmless to Aspergillus sp 2.