Sudachitin is an orally active compound that potently inhibits mouse PDE1C and human PDE4B, with IC50 values of 5.0 µM and 15.0 µM, respectively. Sudachitin upregulates Sirt1 and PGC-1alpha expression in skeletal muscle to regulate energy metabolism and promote mitochondrial biogenesis. Sudachitin improves lipid metabolism, glucose tolerance, insulin sensitivity, energy expenditure, and fatty acid beta-oxidation. Sudachitin activates p38MAPK signaling, induces HSP27 phosphorylation and caspase-dependent apoptosis, and blocks EGF-driven keratinocyte migration and proliferation. Sudachitin suppresses LPS-induced TNF-alpha, NO, and iNOS expression in macrophages and shows potent anti-inflammatory activity. Sudachitin can be used for the research of metabolic syndrome, type 2 diabetes, and psoriasis.[1][2][3].