Authors : Zeleria Yusuf, Gebremeskel Mebrate, Mulugeta Desta and Sewnet Mengistu
Abstract: Milk thistle (Silybum marianum L.) fruit extract (silymarin) is a flavonolignan called silybin that has been indicated to conserve animal livers against the harming impacts. The present study was aimed to examine physicochemical properties antioxidant and antimicrobial activities of oil extracted from S. marianum, seeds and leaves. The oil extraction was done in Soxhelt apparatus using petroleum ether as a solvent. Then, physicochemical properties of the oil extracts were conducted based on determination of oil content, specific gravity, acid value, percent free fatty acid and peroxide values. The antioxidant activity was investigated based on determination of ascorbic acid content, DPPH and hydrogen peroxide free radical scavenging activities. The antimicrobial activity test were conducted using disc diffusion method and broth dilution method. The result of physicochemical properties of S. marianum seed and leaf oils indicated significance differences between seed and leaf oils were obtained for all measured parameters. It was found that oil yield (44.5%), specific gravity (0.89), acid value (1.54) and free fatty acids (0.78% were significantly higher for seed oil extract. The antioxidant activities of S. marianum seed and leaf oil extracts presented significantly higher antioxidant activities with respect to ascorbic acid content (55.05’1.47) and DPPH value (18.00’2.55) for seed oil than for leaf oil. Stronger antibacterial activity with maximum zone of inhibition (15.50mm), bactericidal activity with MIC (0.06 μL/mL) and MBC (0.12 μL/mL) were recorded for leaf oil extract against S. aureus. The stronger antifungal activity with maximum zone of inhibition (13.83 mm), MIC (0.25 μL/mL, the least value) and MFC (0.50 μL/mL) were recorded for seed oil against A. versicolor. Thus, milk thistle has low peroxide and acid values which show its low oxidation rancidity and high biological activities make it suitable for nutraceutical and drug development.
Zeleria Yusuf, Gebremeskel Mebrate, Mulugeta Desta and Sewnet Mengistu, 2021. Physicochemical Properties, Antioxidant and Antimicrobial Activities of Milk Thistle (Silybum marianum L.) Seed and Leaf Oil Extracts. Research Journal of Medical Sciences, 15: 78-82.