Optimization, characterization and biological properties of phenolic compounds extracted from Rosmarinus officinalis

Abstract

This study evaluated the optimal conditions for the extraction of phenolics from Rosmarinus officinalis. Phenolic extracts were obtained under extraction conditions in which several parameters were varied (time, temperature, solvents and free and bound forms). The results revealed that the optimum conditions for maximum phenolic content extraction and antioxidant activity were achieved using a mixture of methanol and water at 60 °C/1 h. However, the optimal extraction conditions for phenolics with the highest hypertensive (ACE) or diabetic (α-amylase and α-glucosidase) enzyme inhibitory activity were observed using a mixture of acetone and water for extraction at 40 °C/6 h or methanol at 50 °C/8 h, respectively. The results indicated that the free and bound phenolic compounds had antioxidant, antihypertensive and antidiabetic properties. The predominant free phenolic compound identified in rosemary was thymol, while chlorogenic and caffeic acids were the predominant bound phenolic compounds.

Keywords:

• Optimization
• antioxidant activity
• inhibitory activity
• ACE
• phenolics
• α-glucosidase
• α-amylase

Acknowledgements

The authors acknowledge the Jordan University of Science and Technology for funding this research. The authors also extend their appreciation to the Deanship of Scientific Research at King Saudi University for funding this work through the research group project (No. RGP-VPP-193).