A trimethoxy flavonoid isolated from stem extract of Tabebuia chrysantha suppresses angiogenesis in angiosarcoma

Objectives This research aimed to evaluate the antiangiogenic activity of isolated flavonoid 4a,5,8,8a‐tetrahydro‐5‐hydroxy‐3,7,8‐trimethoxy‐2‐(3,4‐dimethoxyphenyl) chromen‐4‐one (TMF) from Tabebuia chrysantha. STAT3‐MMP9 signalling is a signal transduction mechanism that promotes angiogenesis in various cancers. Methods The tumour xenografting chicken embryo chorioallantoic membrane (CAM) model‐based ex vivo assay was used to evaluate the activity of TMF. The Western blot, densitometric analysis and quantitative real‐time polymerase chain reaction (qRT‐PCR) were performed to evaluate the activity of the MMP9. Zebrafish embryos were used to evaluate embryotoxicity, and in vitro free radical scavenging activity of flavonoid was also elucidated. Key findings This research assessed the high level of STAT3, p‐ERK, VEGF‐R and MMP9 in the tissue extract of the control group, and also, the suppression of angiogenesis in the treatment groups was due to scavenged ROS and RNS, dephosphorylation of STAT3 and ERK, and suppression of MMP9 gene expression. Conclusion The isolated flavonoid named TMF from T. chrysantha functions as specific regulators of target proteins of angiosarcoma. The STAT3‐MMP9 signalling may be used as an effective prognostic marker of angiosarcoma.