Chemical constituents, antioxidant and antibacterial activities of the hexane extract of Alchemilla sericata Reichenb

The hexane extract from the aerial parts of Alchemilla sericata Reichenb. which was collected from Khalkhal-Asalem road, Ardabil Province, northwestern Iran, was obtained using a commercially available Soxhlet apparatus. The fatty acids were derived to methyl esters and determined through gas chromatography/flame ionization detector (GC/FID) and gas chromatography/mass spectrometry (GC/MS) systems. The extract was characterized by high amounts of saturated fatty acids (SFA) (66.0%) along with lower quantities of some other terpenoid compounds. Accordingly, the main components of the hexane extract were found to be hexadecanoic acid (41.4%), 9,12-octadecadienoic acid (21.0%), octadecanoic acid (18.0%) and dioctylphthalate (7.7%), respectively. The hexane extract from A. sericata was also detected as a rich source of an important source of palmitic acid compound. In addition, its antioxidant activity was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The results indicate that extracts from the aerial parts of A. sericata possess considerable antioxidant activity. The highest radical scavenging activity was detected in this plant oil (IC50=185 μg/mL). The antimicrobial activity of the hexane extract sample were determined against seven Gram-positive and Gram-negative bacteria (Bacillus subtilis, Enterococcus faecalis, Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae), as well as three fungi (Candida albicans, Saccharomyces cerevisiae and Aspergillus niger). The bioassays used showed that the hexane extract exhibited a moderate antimicrobial activity. This study revealed that the extracts from the aerial parts of this plant are potential sources of fatty acid components, as well as effective natural antioxidants.