MMP9 and melanoma: Luteolin, a natural flavonoid, found in fruits, vegetables and medicinal herbs, was reported to reduce EMT, angiogenesis and metastasis in CM through downregulation of HIF-1α, p-Akt, VEGF-A, p-VEGFR-2, MMP2, and MMP9 proteins expression, although the pharmacological action and mechanism of luteolin on the metastasis of melanoma was not completely elucidated [122].