Ameliorating Effects of Corosolic Acid in Monocrotaline-Induced Pulmonary Hypertensive Rats

Pulmonary arterial hypertension (PAH) is a progressive and fatal disease of the cardiovascular system. PAH is characterized by thickening of the pulmonary artery wall (remodeling) and often causes inflammation around the pulmonary artery. It has been reported that corosolic acid (CRA), is a pentacyclic triterpene acid contained in banaba leaves, has anti-inflammatory, anti-diabetic, and anti-cancer effects. In the present study, the effects of CRA on the pathogenesis of PAH were examined using monocrotaline (MCT)-induced pulmonary hypertensive (PH) rats. Male SD rats (4 weeks-old) were injected subcutaneously with vehicle (saline; control) or MCT (60 mg/kg). CRA (1 mg/kg) was administered intraperitoneally daily from 1 week after MCT injection. At 3 weeks after MCT injection, the effects of CRA on the in vivo parameters of PAH pathogenesis were analyzed. Hematoxylin and eosin (H&E) staining revealed that CRA clearly improved PAH remodeling in MCT-induced PH rats. The treatment with CRA also reduced the Fulton ratio (an index of right ventricular hypertrophy) in MCT-induced PH rats. Furthermore, CRA significantly lowered right ventricular systolic pressure (RVSP) in MCT-induced PH rats. In contrast, CRA did not affect these parameters in control rats. Taken together, CRA may be useful as a novel therapeutic candidate for PAH.