Antioxidant Properties of Twelve Selected Medicinal Plants Commonly Used in Jordan

Aims: To characterize the antioxidant properties of twelve selected medicinal plants commonly used in Jordan in traditional medicine. Methodology: The following in vitro antioxidant assays were used: total antioxidant capacity, DPPH free radical scavenging , ferric reducing, ferrous chelating, total phenols and flavonoids. Results: Considering the overall antioxidant activities (µg AA equivalent /mg extract), the studied plants were arranged in the following decreasing order of their extract strength: Pista cia palaestina Boiss. (232) > Arbutus andrachne L. (197) > Hypericum triquetrifolium Turra (186) > Zingiber officinale Roscoe (1 85) > Mentha spicata L. (184) > Rosmarinus officinalis L. (183) > Salvia triloba L.f. (154) > Verbena triphylla L’H’er. (117) > Origanum syriacum L. (109) > Teucrium polium L. (96) > Nigella sativa L. (80) > Ceratonia siliqua L. (69) . When the antioxidant capacity of the dry weights (g AA equivalent /100g dry weight) of tested plants was calculated, the plants were arranged from th e strongest to the weakest as follows: Pistacia palaestina Boiss. (7.1%) > Arbutus andrachne L. (6.1%) > Hypericum triquetrifolium Turra (4.3%) > Salvia triloba L.f. (2.4%) > Rosmarinus officinalis L. (2.2%) > Ceratonia siliqua L. (1.9%) > Zingiber officin ale Roscoe ( 1.4% ) > Nigella sativa L.