Evaluation of the Antiangiogenic Activity of Thymus serpyllum Aerial Parts Extracts Using the Chorioallantoic Membrane Assay.

BACKGROUND AND AIM: Unregulated excessive angiogenesis is a hallmark of many diseases, including cancers, rheumatoid arthritis, and diabetic retinopathy. Plant Thymus serpyllum is well-known for its wide range of pharmacological effects. This study aimed to determine the in vivo antiangiogenic activity of Thymus serpyllum in fertilized chicken eggs using the chorioallantoic membrane (CAM) assay. MATERIALS AND METHODS: The plant Thymus serpyllum aerial parts extract was prepared by maceration. The fourth-day fertilized chicken eggs were incubated. On the fifth day, eggs were windowed, and albumin was withdrawn. On the sixth day, 0.5% and 1% extracts were applied to the chorioallantoic membrane area, and the eggs were then reincubated. On the seventh day, CAM vasculature was imaged, and the diameter (primary, secondary, and tertiary), height (Abbott curve), and orientation pattern with amplitude of (angular spectrum) of blood vessels were measured by MountainsSPIP software (Besançon, France: Digital Surf). A relative comparison of the control and extract treatment groups was conducted. RESULTS: The control group exhibited a well-developed vascular network, characterized by dense and prominent branching of blood vessels with increased diameter; a steep Abbott curve, indicating increased complex vasculature and surface roughness; and a broad angular spectrum, revealing high amplitude and uniform orientation of blood vessels. In contrast, the 0.5% and 1% extracts reduced the dense vasculature, complexity, diameter of primary, secondary and tertiary blood vessels, uniform directionality, and amplitude of blood vessels in the angular spectrum. The 1% extract showed fading of tertiary blood vessels. Both extracts showed a gradual decline in the Abbott curve, but 1% extract showed a decrease in the height of blood vessels.  Conclusion: Thymus serpyllum 0.5% and 1% extracts exerted antiangiogenic effect on blood vessels in fertilized chicken eggs by reducing the vascular network, surface roughness, amplitude, and orientation pattern of blood vessels with a decrease in height by 1% extract. The antiangiogenic activity of Thymus serpyllum can be utilized therapeutically to treat various diseases associated with unregulated neovascularization.