Correlation of total polyphenolic content with antioxidant and antibacterial activity of 24 extracts from Greek domestic Lamiaceae species

Lamiaceae family species are considered important because of their use in folk medicine, culinary and flavouring throughout the world. Their interesting bioactivities are attributed mainly to essential oils, polyphenols and terpenes. However, there are only few studies about polyphenolic extracts from Lamiaceae plants. Thus, 24 polyphenolic extracts from three Lamiaceae genera, Salvia, Mentha and Sideritis, collected in Greece were examined for antioxidant and antibacterial activity in correlation with their polyphenolic content. The results showed that the tested polyphenolic extracts had strong free radical scavenging activity against DPPH and ABTS+ radicals and protected from hydroxyl and peroxyl radical-induced DNA damage. Moreover, five extracts inhibited Staphylococcus aureus growth. Furthermore, the results showed that the total polyphenolic content is not correlated with the above activities, although this relation was different within each plant genus. This is the first study regarding the antioxidant and antibacterial activity of Salvia pomifera ssp. calycina, S. pomifera ssp. pomifera, Mentha microphylla and Sideritis raeseri ssp. attica species, and one of the few concerning protection from DNA damage and antibacterial activity of polyphenolic extracts from the rest of the tested species.

► Polyphenolic extracts from Salvia, Mentha and Sideritis had strong free radical scavenging activity. ► All the tested extracts protected from hydroxyl and peroxyl radical-induced DNA damage. ► Five extracts inhibited Staphylococcus aureus growth. ► The total polyphenolic content is not correlated with the observed activities. ► The results suggest the potential use of the extracts as natural food preservatives and supplements.