Chemical and biological evaluation of rosemary (Rosmarinus officinalis L.) leaves volatile oil and its methanolic extract.

摘要

The functional activities of rosemary leaves volatile oil (RVO) and its methanolic extract, as new and natural sources having biological active compounds, as antioxidants and antifungal agents, were assessed. As well as, the effect of RVO as anti-inflammatory, analgesic and hepatoprotective agents on Albino rats were also tested. Volatile oil was separated and its constituents were identified using GC and GC/MS. The antioxidant effects of rosemary leaves and its methanolic extract were evaluated by various antioxidant assays. The stable free radical species, free radical scavenging activities using DPPH assay and the oxidative stability of sunflower oil using Ransimat assay were also studied. Moreover, the antifungal activity of RVO against two strains of spoilage fungi namely, A. flavus and A. ochraceus was tested. Rosemary volatile oil was characterized by the presence of high percentage of oxygenated compounds and monoterpene hydrocarbons. The major volatile fraction was 1,8 cineole, predominant alcohol, representing about 25.602%. Pyrogallic acid was the most abundant phenolic compound in rosemary leaves (10.764 mg/gm). Rosemary methanolic extract exhibited a strong free radical scavenging activity (100%). In addition, the high content of total phenolic compounds of rosemary showed a good protection against oxidation and increased the shelf life of sunflower oil. Furthermore, it had a high antioxidant activity and could be considered as an important source of natural antioxidants, as well as it proved to be superior to BHT especially, at a level of 200 ppm. Also, rosemary volatile oil exhibited considerable inhibitory effects against the two organisms under test. The rosemary leaves volatile oil (1.3 mg/Kg b.wt), exhibited a high acute anti-inflammatory activity and its potency was 36.19% as compared to Indomethacin (the reference drug). Moreover, the potency of chronic anti-inflammatory effect was 41.94 and 66.71% for RVO and Indomethacin administration, respectively. RVO has equivalent anti-inflammatory and analgesic activities compared with current non-steroidal anti-inflammatory drugs in preclinical animal models, without having substantially different gastrointestinal side effect profile. Furthermore, RVO administration resulted a significant improvement of signs of the liver functions. Moreover, the histological examination of liver tissues revealed that the treatment with rosemary volatile oil plus CCL4 showed minimal histological lesions and mitotic hepatocytes. Therefore, RVO could be used as hepato-protective agent, besides, it could be concluded that this study is of great importance from the economical and application view points. Further studies including rosemary incorporated in food items would be of value.