The antimicrobial and antioxidant activities of some Hypericum and Achillea species

IV ABSTRACT In this study, the antimicrobial, antifungal and antioxidant properties of crude methanol, ethanol and water extracts of medicinally important plants Hypericum retusum Aucher, Hypericum scabrum L., Hypericum lysimachioides Boiss.&Nöe var. lysimachioides, Achillea aleppica D.C. subsp. aleppica, Achillea aleppica D.C. subsp. zederbaueri (Hayek) Hub.-Mor., Achillea biebersteinii Afan. belonging to Hypericum and Achillea family and growing in South East of Turkey were investigated. The antimicrobial and antifungal activity of plants extracts were performed by disc diffusion assay against several bacteria. The results showed that the ethanolic crude extracts of all tested plant exhibited different activity against tested microorganisms. One of the recognised modes of action of EDTA is the disruption of the lipopolysaccharide structure in the outher membrane of Gram-negative bacteria. Through this disruption the membrane becomes more permeable to other agents. Therefore the antimicrobial activities of the EDTA added crude extracts of all plants were also studied. It has been found that the zone diameter increased by the extract obtained from H. retusum and A. aleppica subsp. aleppica on Pseudomonas aeruginosa, and the zone diameter was not changed by the extracts of H. scabrum and H. lysimachioides. On the other hand the zone diameter was reduced by the extracts of A. aleppica subsp. zederbaueri and A. biebersteinii. The crude methanol and water extracts of plants did not show any antimicrobial activity against tested microorganisms. The antioxidant activities of crude ethanol and water extracts of plants were evaluated by several in vitro systems, e.g. DPPH radical scavenging activity, metal chelating ativity and determination of total phenolic compounds. The DPPH radical scavenging ability of crude ethanol and water extracts of H. retusum were found to be in the range of 67.40- 85.00 %, and 39.70-45.40 %, respectively, at the concentration range between 50-500 [Ag/mL. The DPPH radical scavenging ability of crude ethanol and water extracts of H. scabrum were found to be in the range of 88.70-92.60 %, and 50.90-54.40 %, respectively, at the concentration range between 50-500 [xg/mL. The DPPH radical scavenging ability of crude ethanoland water extracts of H. lysimachioides were found to be in the range of 90.00-94.20 %, and 49.40-56.00 %, respectively, at the concentration range between 50-500 \ig/mL. The DPPH radical scavenging ability of crude ethanol and water extracts of A. aleppica subsp. aleppica were found to be in the range of 67.80-89.80 %, and 39.80- 43.90%, respectively, at the concentration range between 50-500 (xg/mL. The DPPH radical scavenging ability of crude ethanol and water extracts of A. aleppica subsp. zederbaueri were found to be in the range of 86.30-90.60 %, and 37.80-47.60%, respectively, at the concentration range between 50-500 [Ag/mL. The DPPH radical scavenging ability of crude ethanol and water extracts of A. biebersteinii were found to be in the range of 86.80 %-91.20, and 39.20-45.80%, respectively, at the concentration range between 50-500 [xg/mL. In the metal chelating activity assay, the chelating ability of crude ethanol and water extracts of plants against Fe2+ were investigated. It has been found that the ethanol and water extracts of plants interfered with the formation of ferrous and ferrozine complex, suggesting that they have chelating activity and capture ferrous ion before ferrozine. The metal chelating capacity of crude ethanol and water extract of H. reretusum were found to be in the range of 18.60-28.40 % and 27.30-30.20%, respectively, at the concentration range between 0.1-0.6 mg/mL. The metal chelating capacity of crude ethanol and water extract of H. scabrum were found to be in the range of 18.30-27.80 % and 29.20-31.00%, respectively, at the concentration range between 0.1-0.6 mg/mL. The metal chelating capacity of crude ethanol and water extract of if. lysimachioides were found to be in the range of 20.20-27.10% and 29.10-30.00%, respectively, at the concentration range between 0.1-0.6 mg/mL. The metal chelating capacity of crude ethanol and water extract of A. aleppica subsp. aleppica were found to be in the range of 27.10-28.40% and 27.30-29.10%, respectively, at the concentration range between 0.1-0.6 mg/mL. The metal chelating capacity of crude ethanol and water extract of A. aleppica subsp. zederbaueri were found to be in the range of 27.90-29.90% and 28.30-30.00%, respectively, at the concentration range between 0.1-0.6 mg/mL. The metal chelating capacity of crude ethanol and water extract of A. biebersteinii were found to be in the range of 25.60-28.70% and 28.30-31.00%, respectively, at the concentration range between 0.1-0.6 mg/mL.VI Phenols are very important plant constituents due to their radical scavenging ability. It is also known that the phenolic compounds shows antioxidant activity. The total phenolic compounds in the both ethanol and water extracts of tested plants were determined as a gallic acid equivalent. 226.0 and 103.0 [xg gallic acid equivalent of phenols was detected in 1 mg of ethanol and water extracts of H. retusum, respectively. 262.0 and 76.00 [xg gallic acid equivalent of phenols was detected in 1 mg of ethanol and water extracts of H. scabrum, respectively. 266.0 and 132.0 [xg gallic acid equivalent of phenols was detected in 1 mg of ethanol and water extracts of H. lysimachioides, respectively. 118.0 and 79.00 |xg gallic acid equivalent of phenols was detected in 1 mg of ethanol and water extracts of A. aleppica subsp. aleppica, respectively. 126.0 and 71.00 |xg gallic acid equivalent of phenols was detected in 1 mg of ethanol and water extracts of A. aleppica subsp. zederbaueri, respectively. 134.0 and 52.00 [xg gallic acid equivalent of phenols was detected in 1 mg of ethanol and water extracts of A. biebersteinii, respectively.