Investigation of the effect of salvia palaestina benth. on the lipoxygenase enzyme

Aim: Many compounds are known to be used in the treatment of inflammatory diseases. However, due to reasons such as side effects and high costs, new alternative sources with anti-inflammatory activity are being investigated. Within the scope of this thesis, it was aimed to investigate the effect of aqueous, methanol extracts and sub-extracts prepared from Salvia palaestina Benth. on the lipoxygenase enzyme and also isolation and structure elucidation of the compounds responsible for the activity was performed by activity guided fractionation studies. Material and Method: Aqueous and methanol extract and n-hexane, dichloromethane, ethyl acetate, n-butanol (and remaining aqueous) sub-extracts obtained from methanol extracts were prepared from the plant. These extracts were evaluated in respect to their inhibitory effects on lipoxygenase enzyme by in vitro method. Activity guided fractionation method was used to isolate the compounds that are responsible for the activity, and structures of the isolated compounds were elucidated by spectroscopic and chromatographic methods. Results: Amongmain and subextracts, methanol extract, dichloromethane and ethyl acetate subextracts were found to inhibit lipoxygenase 29% (p<0.001), 58% (p<0.0001) and 70% (p<0.0001), respectively. Rosmarinic acid and methyl rosmarinate were found to be responsible for the activity, and their IC50 values were calculated to be 76.0 and 8.2 µg/mL, respectively. Apigenin and apigenin 7-O-glucuronide obtained from the active fractions were inactive. Conclusion: Inhibitory effect of Salvia palaestina on lipoxygenase was investigated for the first time with this study and the compounds responsible from this activity were determined by means of activity guided fractionation method. Keywords: Salvia palaestina, Lipoxygenase, Medicinal plant, Rosmarinic acid, Activity guided fractination