Abstract
In
the presented study, a comparative analysis of phenolic compounds,
parallel with antioxidant and antimicrobial activity of selected plants
from Spanish medicinal flora was conducted. Total phenolic content,
flavonoid concentrantions, antioxidant activity and antioxidant
capacity, as well as antimicrobial activity were determined for
methanolic extracts from 21 medicinal or potential medicinal plants
sampled from eight different locations on the teritory of Spain. The
phenolic content, antioxidant properties and antimicrobial activity were
determined for the first time for some analyzed species. Results for
total phenolic content determined using Folin-Ciocalteu reagent and
expressed in term of gallic acid equivalent, GAE (mg of GA/g of extract)
ranged from 35.67 to 286.18 mg of GA/g of extract. The concentrations
of flavonoids determined using spectrophotometric method with aluminium
chloride and expressed in terms of rutin equivalent, RuE (mg of Ru/g of
extract) ranged from 31.58 to 147.34 mg of Ru/g of extract. Antioxidant
activity was determined using DPPH (1,1-diphenyl-2-picrylhydrazyl
radical) reagent and was expressed as IC50 (concentration of sample
which is required to scavenge 50% of radicals), where values ranged from
123.80 to 14.77 μg/ml. Obtained results for antioxidant capacity
evaluated using the Briggs-Rauscher oscillating reaction method ranged
from 190.00 to 19.00 min. Antimicrobial activities of the studied
methanol extracts were determined against three gram positive, three
gram negative and two fungal strains using microdilution method.
Investigated extracts exhibited variable activities with minimal
inhibitory concentrations ranging from 0.01-20.00 mg/ml. A significant
relation was noticed between the phenolic content, antioxidant activity
analyzed through both methods and antimicrobial activity. High amounts
of phenolics responsible for the good biological activity of the
extracts from the tested plants is in connection with the local, zonal
imposed habitat characteristics. The findings of our comparative study
and interpretations of the obtained results promote the Mediterranean
medicinal flora as an effective source of bioactive substances.
