The in vivo evaluation of anti-angiogenic effects of Hypericum essential oils using the chorioallantoic membrane assay

Abstract Context. Hypericum species including Hypericum confertum Choisy, H. hircinum L., H. hyssopifolium Chaix. subsp. elongatum (Ledeb.) Woron var. microcalycinum (Boiss. & Heldr.) Boiss. and H. perforatum L. (Clusiaceae) are used as medicinal plants in Turkey. Objective: The anti-angiogenic evaluation of Hypericum essential oils using the chick embryo chorioallantoic membrane (CAM) assay are performed with this study for the first time. Materials and methods: The anti-angiogenic activity of Hypericum essential oils (0.5-5.0 mg/ml) was evaluated in vivo using the CAM assay, compared to standard anti-angiogenic substances at the same concentrations, in trice replicated independent assays. GC and GC-MS analyses were carried out simultaneously to identify the chemical compositions of the Hypericum essential oils. Results: The CAM treated with H. perforatum essential oil showed anti-angiogenic effect (score 0.6 ± 0.3) at 50 µg/pellet concentration, whereas other tested Hypericum essential oils showed no effect compared to the standards (e.g. suramin score 0.5 ± 0.2). Furthermore, the tested oils showed neither membrane toxicity nor irritation at the tested concentrations. The major compound of the essential oil of H. confertum was identified as germacrene D (30.2%). The major compound of the essential oils of the H. hircinum. H. hyssopifolium subsp. elongatum var. microcalycinum and H. perforatum was identified as α-pinene (88.3, 57.8, 33.3%), respectively. Discussion and conclusion. Hypericum species and in particular H. perforatum essential oil may have important effect toward wound healing and various inflammations. The data obtained in this experiment suggest further investigations on various cancers due to its anti-angiogenic effects observed.