Antimicrobial and antioxidant activities of the various extracts of Verbascum pinetorum Boiss. O. Kuntze (Scrophulariaceae).

Background and Objectives: The present study was performed to evaluate the in vitro antimicrobial and antioxidant properties of various extracts of Verbascum (V.) pinetorum, a member of Scrophulariaceae family. While the antimicrobial activity of various extracts of V. pinetorum was determined with agar-well diffu- sion method, the antioxidant activity was exam- ined with two complementary test systems, namely 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and β-carotene/linoleic acid test systems. Results: The hexane extract exhibits antimi- crobial activity against few microorganisms. However, dichloromethane, direct methanol and methanol/chloroform extracts are effective on a broad range of microorganisms. Among the test- ed bacteria Haemophilus influenzae was found to be the most sensitive bacterium. The 50% (IC50) inhibition activity of the methanolic extract of V. pinetorum on the free radical DPPH was de- termined as 13.04 mg/ml. In the case of the linoleic acid system, oxidation of linoleic acid was inhibited by methanolic extract of V. pineto- rum, which showed 89.39% inhibition that is quite close to the value of the synthetic antioxi- dant reagent butylhydroxytoluene (BHT), 92.46%. Iridoid glycosides, flavonoids and saponins were determined as the major natural com- pounds in the methanolic extracts. The total phenolic components of V. pinetorum were found as 42.45 mg/g gallic acid equivalent. Conclusion: The results provide evidence that the extracts of V. pinetorum contained iri- doid glycosides, flavonoids, saponins and phe- nolic compounds which may be responsible for the substantial antimicrobial and antioxidant ac- tivities.