Ponencia
Phytochemical studies and hypoglycemic activity of extracts from Gleichenia squamulosa (Pteridophyta)
Fecha
2017Institución
Resumen
Ferns have been used for ornamental purposes as well as for medicinal purposes. Accordingly, the
production of secondary metabolites with various biological activities could be useful in the
treatment of various diseases. In addition, pharmacological and ethnopharmacological studies
have revealed that some ferns have compounds with hypoglycemic effects. The objectives of this
study were to evaluate the inhibitory effect of different extracts of the fern Gleichenia squamulosa
colleted en Chiloe on the enzyme α-glucosidase and to determine the presence of secondary
metabolites. Metabolites phytochemical screening was performed by colorimetric and
precipitation reactions. To evaluate the inhibitory capacity on a-glucosidase, extracts were
prepared by Soxhlet (ethyl acetate, and methanol) and by maceration in water:methanol (70:30),
and concentrated on a rotary evaporator. We studied the inhibitory capacity on α-glucosidase
using p-nitrophenyl-1,4-α-glucopyranoside as substrate. Aqueous solutions were prepared at
different concentrations of each extract (among 10 - 2000 μg mL-1). Extracts at different
concentrations were tested as enzymatic inhibitors using acarbose as a positive control. The
percent inhibition was determined by colorimetry on a UV-VIS spectrophotometer at 400 nm.
Phytochemical studies showed the presence of flavonoids, sesquiterpene lactones, coumarins,
tannins and phenols. The results of enzymatic inhibition present values of IC50 (50% of inhibition
capacity) of 270, 645 and 733 μg mL-1 for methanol, ethyl acetate and hydro-alcohol respectively.
In the case of acarbose, it showed an IC50 = 1016 μg mL-1. It has been documented that some
phenolic compounds as myricetin, baicalein and epigallocatechingallate are responsible for
inhibiting α-glucosidase. In conclusion, this study suggests that the presence of different
secondary metabolites from Gleichenia squamulosa could have pharmacological activities as α-
glucosidase inhibitor.