Labiatae family is represented in Saudi Arabia. It is one of the most distinctive families of flowering plants with a great diversity. This study aimed to investigate in vitro antioxidant and antiprotozoal activities of methanolic extract of Mentha longifolia (ML) and Origanum syriacum (OS). OS exhibited high phenolic contents (mg gallic acid equivalent g-1 weight) 87±3.5 mg GAE g-1. ML produced 23±3.2 mg GAE g-1. Using potassium ferricyanide method, OS exhibited high absorbance after 120 h (0.53±0.037) that was directly proportional to the reducing power, however, ML produced lower absorbance (0.38±0.031). Percentage scavenging activity against diphenyl-2-picryl-hydrazyl radical was 875 (OS) and 128% (ML). Absorbencies of ferric thiocyanate assay was 0.86 and 0.25 for ML and OS, respectively. Using phosphomolybdenum method, OS exhibited antioxidant activity (80%) followed by ML (55%). Percentage superoxide scavenging activities was 47 (OS) and 15% (ML). OS exhibited antimalarial activity against P. falciparum-K1 strain in contrast to ML. OS extract exhibited activity against T. cruzi. ML exhibited activity against T. cruzi. OS exhibited activity against T. b. brucei. However, ML showed no marked activity against T. b. brucei. ML and OS exhibited no marked activity against L. infantum. Both ML and OS exhibited no marked cytotoxic activity against MRC-5 cells. It was concluded that, ML and OS have the potency to act as powerful antioxidants and to some extent as antiprotozoal.
Khalil H. Al-Ali, Hesham A. El-Beshbishy, Abdulaziz A. Alghaithy, Hossam Abdallah, Ayman A. El-Badry and Essam Abdel-Sattar, 2013. In vitro Antioxidant Potential and Antiprotozoal Activity of Methanolic Extract of Mentha longifolia and Origanum syriacum. Journal of Biological Sciences, 13: 207-216.