Antioxidant and antimicrobial properties of Moltkia petraea (Tratt.) Griseb. flower, leaf and stem infusions.

Antioxidant and antimicrobial activities as well as the quantity of phenolic substances (total phenol, flavonoid and phenolic acid contents) were determined in aqueous extracts of leaves, stems and flowers of Moltkia petraea (Tratt.) Griseb. from two mountainous localities (Sveti Jure and Snijeznica) in Croatia. In addition, the profile of phenolic acids was analyzed by UPLC-MS/MS. Antioxidant activities of all extracts in different test systems, namely the DPPH radical scavenging, reducing power assay and chelating activity, increased with extract concentration. Activity of the extracts from Snijeznica in beta-carotene-linoleic acid assay did not differ from the activity of standard, BHA. The leaf extracts from Snijeznica demonstrated superior antioxidant activity in most of the assays, while the stem extract from the same locality was the most effective Fe(2+) ion chelator. In general, the extracts from Snijeznica were more effective antioxidants than the corresponding extracts from Sveti Jure. The aqueous extracts of M. petraea did not show antimicrobial activity against bacteria and fungi tested in the diffusion and dilution assays.