Chalcones in Bioactive Argentine Propolis Collected in Arid
Environments
Nat Prod Commun, 2012 Jul;7(7):879-82
The aim of this study was to assess the chemical and
biological profile of propolis samples collected in arid environments of
north-western Argentina.
The samples were from two phytogeographical regions (Prepuna
and Monte de Catamarca Province). Propolis ethanolic extracts (PEE) and
chloroform (CHL), hexane (HEX) and aqueous (AQ) sub-extracts of samples from
three regions (CAT-I; CAT-II and CAT-III) were obtained. All PEE exhibited
antioxidant activity in the DPPH radical scavenging assay (SC50 values between
28 and 43 microg DW/mL). The CHL extract was the most active (SC50 values
between 10 and 37 microg DW/mL). The antioxidant activity in the beta-carotene
bleaching assays was more effective for PEE and CHL (IC50 values between 2 and
9 microg DW/mL, respectively). A similar pattern was observed for antibacterial
activity.
The highest inhibitory effect on the growth of human
Gram-positive bacteria was observed for CHL-III and CHL-I (Monte region) with
minimal inhibitory concentration values (MIC100) of 50 to 100 microg DW/mL.
Nine compounds were identified by HPLC-PAD. Two of them (2', 4'-
dihydroxychalcone and 2',4'- dihydroxy 3'-methoxychalcone) were found only in
propolis samples from the Monte phytogeographical region.
We consider that the Argentine arid region is appropriate to
place hives in order to obtain propolis of excellent quality because the
dominant life forms in that environment are shrubby species that produce
resinous exudates with a high content of chalcones, flavones and flavonols.
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