Phytochemical, antioxidant and antibacterial properties of extracts from two spice herbs under different extraction solvents

Abstract

Mountain fennel (Zaravschanicamembranacea) and Ferulagoangulata belonging to the Apiaceae family are important aromatic and spice plants in Iran, which the aerial parts of these herbs are used as flavoring agents in dairy foods. This investigation was devoted to the determination of total phenols and flavonoids contents of Z.membranacea and F.angulata after their extraction using three solvents (ethanol, n-hexane, and methanol), as well as the determination of the antioxidant and the antibacterial activities of all obtained extracts. The results indicated that methanol appeared the most effective solvent for polyphenols and flavonoids’ extraction for both herbs. In fact, the highest total phenols and flavonoids contents among the six prepared extracts from two herbs were found in the methanol extract of Z.membranacea. The results indicated that the extracts of have diverse antioxidant capacities, however, the methanol extract of Z.membranacea exhibited the highest antioxidant activities by DPPH, FRAP and ABTS assays.  Moreover, the antibacterial activity of different extracts was evaluated using the disk diffusion agar method against Salmonellaenterica and Pseudomonasaeruginosa, and Bacillussubtilis and Staphylococcusepidermidis. The highest inhibition zone was obtained from the methanol extract of Z.membranacea for four bacteria. Similarly, the maximum antibacterial activity (MIC) also was obtained from the methanol extract of Z.membranacea for four bacteria. Positive and significant correlations were noted between the phenolic and flavonoid contents and antioxidant activities by DPPH, FRAP, and TEAC assays.  In conclusion, methanol was found to be the best solvent of choice for the extraction of phenolic and flavonoid compounds rich extracts with free radical scavenging and antibacterial activities. Further studies should focus on the isolation and identification of active secondary metabolites from the extracts from Iranian herbs.