Loureirin B (LB, LrB), a flavonoid extracted from Dracaena cochinchinensis, is an inhibitor of PAI-1 with IC50 of 26.10 μM. Loureirin B downregulates p-ERK and p-JNK in TGF-β1-stimulated fibroblasts. Loureirin B promotes insulin secretion mainly through increasing Pdx-1, MafA, intracellular ATP level, inhibiting the KATP current, influx of Ca2+ to the intracellular.