Phyllodulcin, an orally active sweetener discovered in Hydrangea macrophylla var. thunbergii, functions as a non-selective phosphodiesterase inhibitor that mitigates allergic reactions by suppressing the activation of lymphocytes. Additionally, it combats obesity through the regulation of leptin levels, genes associated with fat browning, and the hypothalamic BDNF-TrkB signaling pathway.