Preclinical (animal) evidence suggests that apigenin may function as an antioxidant, anti-inflammatory, and/or means to resist pathogenic infection.[1][2][3][4] Apigenin’s anti-inflammatory effects (typically seen at concentrations of 1–80 micromolar) may be derived from its ability to suppress the activity of some enzymes (NO-synthase and COX2) and cytokines (interleukin 4, interleukin 6, interleukin 8, interleukin 17A, and TNF-α) that are known to be involved in inflammatory and allergic responses.[5][6][7][8][2][9][10] On the other hand, apigenin’s antioxidant properties (seen at concentrations of 100–279 micromolar/L) may be due in part to its ability to scavenge free radicals and protect DNA from free radical damage.[11][12][13] Apigenin may also serve as an adjunctive to stave off the proliferation of parasites (at concentrations of 5–25 μg/mL), microbial biofilms (at a concentration of 1 millimolar), and viruses (at concentrations of 5–50 micromolar), suggesting it may have the potential to improve resistance to infection.[3][4][14]
Though there is little clinical evidence available on apigenin’s effect on immune health, what evidence there is does suggest some anti-inflammatory,[15][16] antioxidant,[17][18] and infection-resistance[19] benefits. It should be noted, however, that all clinical evidence explores apigenin as a part of its source (i.e., plants, herbs), so these effects cannot be attributed to apigenin alone.