Based on the role of HO-1 in the development of obesity and insulin resistance, Wang et al. proved that butein (20) activates the p38 MAPK/Nrf2/HO-1 pathway to act as a potent inhibitor of adipose hypertrophy and inflammation in a diet-induced obesity mouse model [142]. Here, HMOX1 is linked to obesity due to melanocortin 4 receptor deficiency.