Transmission electron microscopy and immunohistochemical characterization of the angiosuppressive activity of the crude methanol extract and hexane fraction of Ardisia squamulosa Presl (Myrsinaceae) from Bataan, Philippines

摘要

Ardisia species have been investigated as rich sources of novel and biologically potent phytochemical compounds. The antiangiogenic potential of the crude methanol extract and hexane fraction at 0.2 ml of 4.0, 6.0 and 8.0 mg/ml of Ardisia squamulosa was determined using duck in ovo chorioallantoic membrane (CAM) assay by counting the branch points of sprouting tertiary (the thinnest) blood vessels. Results showed that the methanol extracts especially the 6mg/ml dose and the 8 mg/ml hexane fraction significantly reduced the branch points of tertiary blood vessels. Transmission electron microscopy showed thicker basement membrane possibly inhibiting outward migration of endothelial cells of extract-treated CAM vessels. Immunohistochemical assays for the factor VIII-related antigen (von Willebrand factor), CD 32, epithelial membrane antigen, platelet endothelial cell adhesion molecule-1 (CD 31), Cyclin D1 and actin proteins showed decreased expression in endothelial cells of CAM vessels treated with crude methanol extract and hexane fractions. Embryo malformation and histological defects of organs could have been due to hypoxia associated with antiangiogenesis.