Background and Aims: Rosmarinus officinalis L. (Rosemary) is an important medicinal plant with broad pharmaco logical activities. Because of their antioxidant activity, products prepared from rosemary extracts are used worldwide. There is no study comparing the antioxidant activities of the commercial products of R. officinalis sold in Trkiye. The study aimed to obtain an extract from rosemary with the highest antioxidant capacity that can be evaluated industrially. Methods: Two commercial products containing rosemary extract available for sale in Trkiye were obtained. Rosemary samples collected from both Trabzon (T) and Aydn (A) were extracted with 100% methanol, 70% methanol, 100% acetone, 100% ethyl acetate, and 30% ethanol. In addition, basic and acidic hydrolysis were used to prepare rosemary extracts with a high phenolic content. The antioxidant capacities of all samples were examined using in vitro 2,2 diphenyl 1 picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), and phosphomolibdenum reducing antioxidant power (PRAP) test systems. Results: It was demonstrated that the rosemary extracts obtained by one step base hydrolysis were the most effective in DPPH (IC 50 values of 12.0 0.1 μg/mL for A and T, respectively), FRAP (A: 500.2 26.4 mg butylated hdroxyanisole equivalents (BHAE)/g extract, T: 487.4 13.5 mg BHAE/g extract, and PRAP (A: 736.6 25.1 mg quercetin equivalents (QE)/g extract, T: 841.8 24.1 mg QE/g extract) assays. These rosemary extracts had the highest total phenolic content (A: 1158.0 11.3 mg gallic acid equivalents (GAE)/g extract, T: 1382.5 11.5 mg GAE/g extract). The rosemary extracts obtained from one step base hydrolysis were more active than the commercial preparations. Conclusion: This is the first study to compare the antioxidant properties of rosemary commercial products with different extraction methods. These findings provide a significant contribution to the literature by revealing various extraction methods that can be used in the development of products with high antioxidant effects from rosemary.
