Validation of the Antifungal Activity of the Tuber of Xanthosoma Robustum (Quequesque) and Determination of Secondary Metabolites Responsible for the Activity

Abstract

The field work was carried out, which consisted of collecting crop plants affected by fungal diseases, identifying in situ some of the fungi present, which were subsequently isolated, purified and identified in laboratories, achieving the identification of three of the 20 isolated fungi, of the five strains used three were isolated and two are strains provided by the Department of
Microbiology of the Faculty of Chemical Sciences and Pharmacy of the University of San Carlos of Guatemala. Once the available phytopathogenic fungi were established, the aqueous and ethanolic extracts of the Xanthosoma robustum plant were obtained. The ethanolic was partitioned liquid-liquid with hexane, chloroform, and ethyl acetate. Subsequently, a phytochemical screening was carried out on the aqueous and ethanolic extracts; obtaining the following results: in the ethanolic extract the presence of alkaloids, flavnoids, coumarins, anthraquinones, tannins, saponins, bitter principles was detected, in the aqueous extract the presence of the same families of metabolites except for flavonoids and bitter principles. The fungicidal activity is attributed to tlavonoids and anthraquinones. For the biological tests, it was possible to determine that there is a broad-spectrum amyfungal effect for all the extracts in concentrations ranging from 0.5 to 0.125 mg/mL. but from 0.05 mg/mL only the ethanolic extract inhibited mycellium growth and at concentrations of 0.0250 mg/mL it was not possible to show an antifungal effect.