TLR4 and major depressive disorder: Isoliquiritin, on the other hand, has also shown to have neuroprotective potentials, as it inhibits monoamine oxidase and ameliorates depression [69,70], while 7-hydroxy-4′-methoxyflavone (formononetin) (15) was able to alleviate neuroinflammation in lipopolysaccharide-stimulated microglial cells by inhibiting TLR4/MyD88/MAPK signaling and activating the Nrf2/NQO-1 pathway [71].