Chalcones in Bioactive Argentine Propolis Collected in Arid Environments

1. SOLÓRZANO E, VERA N , CUELLO S., ORDOÑEZ R., ZAMPINI C, MALDONADO L, BEDASCARRASBURE E, ISLA MI.

NATURAL PRODUCT COMMUNICATIONS

NATURAL PRODUCTS INC

Lugar: Westerville, Ohio; Año: 2012 p. 879 - 882

1934-578X

The aim of this study was to assess the chemical and biological profile of propolis samples collected in arid environments of Northwestern Argentina. The samples were obtained from two phytogeographical regions (Prepuna and Monte of Catamarca province). Propolis ethanolic extracts (PEE) and chloroformic (CHL), hexanic (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 by DPPH radical scavenging assay (SC50 values between 28 and 43 µg DW/mL). The CHL extract was the most active (SC50 values between 10 and 37 µg DW/mL).  The antioxidant activity by b-carotene bleaching assays was more effective for PEE and CHL (IC50 values between 2 and 9 µg 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 µg 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 considered that the Argentine arid region is appropriate to place hives in order to obtain propolis of excelent 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.