In Vitro and in Vivo Antioxidant Related Effects of Rosemary ( Rosmarinus Officinalis L.) Extracts in Humans

Rosemary ( Rosmarinus officinalis L.) belongs to the family Lamiaceae (Labiatae) is a well-known aromatic plant used all around the world for different medicinal purposes. Aims: The present work aimed to investigate antioxidant related effects of rosemary in humans by in vitro and in vivo studies. Study design: Chemical antioxidant assays and venous blood from healthy volunteers were used to conduct in vitro experiments. For in vivo study, nine healthy volunteers, each received orally 250 ml of aqueous extract of rosemary daily for 5 days. Venous bloods were taken before and one hour after the first dose of aqueous extract (sample I and II respectively) and then one day after the last dose of day five (i.e. day 6, sample III). The first blood taken before the first dose (i.e. sample I), served as control for the next samples of II and III. Methodology: The following assays were performed: total antioxidant capacity (TAC), reducing power, scavenging activity of DPPH, scavenging activity of OH, iron chelating ability, erythrocyte reduced glutathione (GSH), malonyldialdehyde (MDA), protein carbonyl (PC), superoxide dismutase (SOD), percentage hemolysis, serum total antioxidant status (TAS) and serum selected biochemical tests. Results: Rosemary extract showed efficient total antioxidant capacity, reducing power, scavenging activity of DPPH, scavenging activity of OH and a reasonable iron chelating ability. Pre-incubation of erythrocytes in vitro with methanolic extract of rosemary then exposed to H₂O₂ decreased significantly MDA production (i.e. anti-lipid-peroxidant), PC production (i.e. anti-protein-oxidant) and oxidant hemolysis (i.e. anti-hemolytic) in a concentration dependent manner. Oral administration of aqueous extracts of rosemary to healthy volunteers, for 5 days, increased significantly serum TAS (18% increase), erythrocyte GSH (72% increase), erythrocyte superoxide dismutase (SOD) (21% increase) and decreased significantly erythrocyte MDA (17% decrease), with no effect on serum biochemical tests for kidney, liver, cardiac and pancreatic, compared to 0 time administration. Conclusion: Rosemary extracts have efficient in vitro and in vivo antioxidant related effects. As the present findings are obtained in healthy humans with no oxidative stress, this indicates that rosemary can improve the base line of the defense mechanisms against possible oxidative stress, with no adverse effects, thus decreasing susceptibility or preventing the progress of pathological conditions related to oxidative stress.