ANTIBACTERIAL AND ANTIFUNGAL ACTIVITIES OF PARASTREPHIA LUCIDA (ASTERACEAE), A PLANT SPECIES FROM THE ARGENTINE PUNA?

D'ALMEIDA ROMINA ELISA; ALBERTO MARÍA ROSA; ZAMPINI IRIS CATIANA; ORDOÑEZ ROXANA M.; ISLA MARÍA INÉS

SAN MIGUEL DE TUCUMAN

Congreso; VII Congreso Argentino de Microbiología General; 2011

Sociedad Argentina de Microbologia

Parastrephia lucida Meyen Cabrera is one of the interesting plant species that grow in the PUNA, a place where extreme conditions like high altitude (3000-4200 meters above sea level), high exposure to UV radiation, low concentration of oxygen, temperature variations (30°C/day) produce particular adaptations on organisms that allow them to survive under these conditions. Our specimen was recollected at 3600 masl from Antofagasta de la Sierra (Catamarca, Argentine). In the folklore medicine it is used as an antimicrobial, antipyretic and anti-inflammatory plant, also for bone fractures and haematomas. In our laboratory we study the antimicrobial activity determining Minimal Inhibitory Concentration and Minimal Bactericidal Concentration (MIC/MBC) by exposing P. lucida methanolic extract (ET), aqueous (AC) and methylene chloride (DCM) subextracts against human pathogen Gram positive and negative bacteria and fungi (methicillin resistant Staphylococcus aureus, methicillin resistant Staphylococcus coagulase negative, St. aureus ATCC29213, Enterococcus faecalis, E. faecalis ATCC29212, Proteus mirabilis, Klebsiella pneumonia, Pseudomona aeruginosa, Escherichia coli, E. coli ATCC35218, Candida albicans, C. tropicalis, C. parasilopsis, C. glabrata and C. guilleirmondii.). The ET did not show antibacterial activity until the higher concentration tested (400 g/ml). The MIC value of ET against all species of Candida was 400 g/ml. However the DCM and AC subextracts did show antibacterial activity against Gram positive bacteria with MIC values of 200 and 400 g/ml, respectively. Against fungi strains both subextracts also showed antimicrobial activity with MIC values between 100 and 400 g/ml. MBC values were not found for any of the microorganism at the highest concentration tested (400 g/ml). Despite DCM and AC subextracts were active; DCM subextract showed the lowest MIC values for almost all the strains tested. According to these results we chosed the DCM subextract to continue with the isolation of the compound/s responsible for the antimicrobial activity for being more active than the ET and AC subextract. A chromatography column with Sephadex LH-20 on the DCM subextract was made and seven fractions (A-G) were obtained. The fractions C, D and E showed MIC values between 100 and 400 g/ml against Gram positive bacteria. Fractions F and G were active not only against Gram positive bacteria, with MIC values of 100 g/ml, but also against Gram negative bacteria with MIC values between 200 and 400 g/ml. For all strains of Candida we found MIC and MBC values between 100 and 400 g/ml. These results show that as we advance in the isolation of the subextract, the active compounds are more concentrated and show higher activity than the fito-complex.