antioxidant and antimicrobial properties of ethanolic extracts of guarana, boldo, rosemary and cinnamon

Abstract

Abstract In this investigation, the ethanolic extracts of two less known plants, little reported in the literature (guarana and boldo leaves) were studied in comparison with the ethanolic extracts of two well studied plants (cinnamon and rosemary), regarding their colour, GC-MS profile, phenolic content and their antioxidant and antimicrobial properties. The rosemary (59.20 ± 0.28) and guarana (56.63 ± 0.54) extracts showed the highest values for luminosity (L*) and the UV-Vis absorption increased when L* decreased. GC-MS identified a limited number of compounds in the cinnamon and guarana extracts. The cinnamon extract showed the highest value for the total phenolic content (172 mg GA/g extract) as compared to the other extracts. The highest antioxidant capacity was observed for the boldo leaves extract in the TEAC (6.66 ± 0.17 mM) assay and for the rosemary extract in the DPPH (0.80 ± 0.14 mg/L) test. In addition, all the extracts showed antimicrobial activity against the S. aureus strain, indicating that all the extracts studied could be used by food industries to develop new active food packaging materials.