Introduction: The aim of this study was to screen the leading compounds of natural origin with anti-angiogenic potential and to investigate their anti-angiogenic mechanism preliminarily.
Materials and Methods: An initial screening of 240 compounds from the Natural Products Collection of MicroSource was performed using the transgenic zebrafish strain Tg [fli1a: enhanced green fluorescent protein (EGFP)]^y1. The zebrafish embryos at 24 h post-fertilization were exposed to the natural compounds for an additional 24 h; then, morphological changes in the intersegmental vessels (ISVs) were observed and quantified under a fluorescence microscope. The expression profiles of angiogenesis-related genes in the zebrafish embryos were detected using quantitative real-time PCR.
Results: Five compounds were identified with potential anti-angiogenic activity on the zebrafish embryogenesis. Among them, deoxysappanone B 7.4ʹ-dimethyl ether (Deox B 7,4) showed anti-angiogenic activity on the formation of ISVs in a dose-dependent manner. The inhibition of ISV formation reached up to 99.64% at 5 μM Deox B 7,4. The expression of delta-like ligand 4 (dll4 ), hes-related family basic helix-loop-helix transcription factor with YRPW motif 2, ephrin B2, fibroblast growth factor receptor (fgfr ) 3, cyclooxygenase-2, protein tyrosine phosphatase, receptor type B (ptp-rb ), phosphoinositide-3-kinase regulatory subunit 2, slit guidance ligand (slit ) 2, slit3 , roundabout guidance receptor (robo ) 1, robo2 , and robo4  were down-regulated, while vascular endothelial growth factor receptor-2, fgfr 1, and matrix metallopeptidase 9 were up-regulated in the zebrafish embryos treated with Deox B 7,4.
Conclusion: Deox B 7,4 has a therapeutic potential for the treatment of angiogenesis-dependent diseases and may exert anti-angiogenic activities by suppressing the slit2/robo1/2, slit3/robo4, cox2/ptp-rb/pik3r2, and dll4/hey2/efnb2a signaling pathways as well as activation of vegfr-2/fgfr1/mmp9.
Keywords: angiogenesis, natural products, deoxysappanone B 7, 4ʹ-dimethyl ether, delta-like ligand 4, slit guidance ligand/roundabout guidance receptor, protein tyrosine phosphatase, receptor type B