Analysis of Extracts From Palestinian Inula Viscosa for Their Phenolic, Flavonoid and Lipid Contents, Antioxidant and Antibacterial Activity

Abstract

Inula Viscosa is one of the most commonly used medicinal plants in countries of Mediterranean region. In this work extracts of different parts of Palestinian Inula viscosa (whole plant, leaves, stems and flowers) were obtained using two solvents (ethanol and methanol), and studied for their Total Phenolic Content (TPC), Total Flavonoid Content(TFC), lipid content 2,2- diphenylpicrylhydrazyl (DPPH) radical scavenging and antibacterial activities. Results had shown that Methanolic extracts of all plant parts had higher TPC, TFC and antioxidant activity than those of extracts obtained using ethanol. Among all extracts, the flower methanolic one had the highest TPC (173.15 mg EGA/g extract) and demonstrated the best antioxidant activity with EC50 of 12.47μg/ml. While the best total flavonoid content was observed for the methanolic extract from leaves (142.5 mg CE/g extract). The total lipid content for extract of all parts was also determined using hexane as extraction solvent, and Leaves showed the highest lipid percentage that is 14.37% from dry plant material. The antibacterial activity of the extracts was studied using agar dilution method on E-coli. For this solutions of extracts with concentrations (10 −2, 10−3 ,10−4 and 10−5 g extract/ml) in 8% aqueous DMSO were prepared and analyzed for their bacterial growth inhibiting activity. The tested extracts in the given concentration range exhibited 90-100% bacterial inhibition. In addition, a liquid hand soap enriched with Inula Viscosa extracts was prepared, and its antibacterial activity was tested both in vitro and in vivo. In vitro study the soap showed complete inhibition of E-coli, while in vivo tests resulted in 50-100% bacterial inhibition.