Actividad antifúngica y citotóxica de extractos hidroalcohólicos de cortezas arbóreas empleadas en medicina tradicional en el Noroeste argentino

BEJARANO GABRIELA; NEGRO MELISA FABIANA; PERALTA MARIANA ANDREA; VERA NANCY

Congreso; 7ma Reunión Internacional de Ciencias Farmacéuticas (RICiFa 2023); 2023

Alnus acuminata (aliso), Anadenanthera colubrina (cebil), Eucalyptus grandis (eucalyptus) Pinus sylvestris (pine), and Polylepis australis (queñoa) are species distributed in the provinces of northwestern Argentina and are used in traditional medicine for the treatment of rheumatic pain, as well as healing, anti-inflammatory, analgesic, among others uses. The aim of the present work was to evaluate the antifungal and cytotoxicity activities of these species and to further explore the knowledge of their chemical composition. Ethanolic and aqueous extracts of barks were prepared according to the method proposed by Mamprim et.al (2014) and according to Farmacopea Argentina 8th Edition. The antifungal activity was evaluated against two clinical strains of Candida albicans, one sensitive (CaS) and the other resistant (CaR) to imidazole antifungals, using the Clinical and Laboratory Standards Institute (CLSI) M27-A4 plate microdilution method. The MIC of the extracts (antifungal concentration that decreases OD 540nm by 50% or more with respect to control growth) was determined. Fluconazole was the reference antifungal with MIC values of 2 µg/ml and 32 µg/ml for CaS and CaR respectively. The evaluations were made at concentrations of 125 to 750 µg/ml for all the extracts. The eucalyptus ethanolic extract was the most active; its MIC was 250 ug/ml, inhibiting the growth of CaS and CaR at 73% and 50%, respectively. For the ethanolic extracts of cebil and queñoa, the MIC was determined at 500 µg/ml for both strains. The MIC of the ethanolic extracts of pine and aliso as well as of the aqueous extracts of all species was higher than 750 µg/ml for both the sensitive and the resistant strains. Cytotoxicity was evaluated using the Artemia salina nauplii viability bioassay, the aqueous extracts being non-toxic (LC50 >1000 µg/ml) and the ethanolic extracts of cebil (LD50: 123.02 µg/ml), eucalyptus (LD50: 190.54 µg/ml) and queñoa (LD50: 186 µg/ml) moderately toxic, according to the Valdés-Iglesias (2003) classification. The detection of groups of secondary metabolites of the extracts of each species was made through a phytochemical march using colorimetric reactions. Reducing compounds, sterols and polysaccharides were identified in all the extracts. Tannin compounds, alkaloids, quaternary amines, flavofenos, anthocyanins, leucoanthocyanins, flavonoids, anthracenoids, bitter principles, coumarins, quinones, sugars and amides vary in the different extracts. Finally, thin layer chromatographic profiles were performed, the mobile phase for the ethanolic extracts in normal phase was chloroform-methanol and chloroform-ethyl acetate in different proportions while for the aqueous extracts, methanol was employed in reverse phase. The results obtained reveal that the ethanolic extracts present a complex chemical composition of substances, since different colors are observed and they present a wide range of polarity. The observed stains could be triterpenes, sterols, flavonoids, coumarins and tannins. The predominant constituents of the aqueous extract are high polarity glycosides.These results suggest the medicinal potential of ethanolic extracts from the bark of eucalyptus, cebil and queñoa, for preventive and/or therapeutic use in topical applications for skin fungal infections.