Syringic acid exerts antiangiogenic activity by downregulation of VEGF in zebrafish embryos

Angiogenesis, the formation of new blood vessels is essential for the conservancy of normal cell func-
tions. The dysfunction and/or increase in angiogenesis may lead to uncontrolled cell proliferation of cells
resulting in cancer. Inhibiting angiogenic factors using natural compound has substantial hope in cancer
research. Hence, we investigated syringic acid (SA), a naturally occurring phenolic acid for its antiangio-
genic property using the zebrafish embryo in vivo model. Morphological observations of the SA treated
embryos were analyzed to evaluate the toxicity of the compound. RBC staining was performed to evaluate
the ISV inhibition in zebrafish embryos. Further, to determine the mechanism behind ISV inhibition, a
real-time reverse-transcriptase polymerase chain reaction and western blot analysis was done to evaluate
VEGF mRNA and protein expression respectively. Our result showed that SA didn’t affect the morphology
up to 50␮M. The apparent angiogenic effect was seen from 20 to 50 ␮M, which significantly reduced
number of circulating red blood cells in ISV region compared to that of control. At 50 ␮M there was no
visible RBC present in the ISV region of the embryos. Further, Real-time PCR and western blot analysis
showed, SA inhibited VEGF mRNA expression and protein expression respectively in a dose dependent
manner. These findings altogether suggest that syringic acid may have antiangiogenic activity by down
regulating VEGF mediated pathway thereby having potential therapeutic benefit and promises to be a
weapon against cancer.