Effect of Methanol Fraction of Aspidopterys indica Aerial Parts on DOCA Salt-Induced Hypertension and HR-LC-MS Assisted Phytochemical Profiling

Abstract

Aspidopterys indica (Willd.) W. Theob. (Malpighiaceae) has been used as traditional remedy for hypertension and skin diseases. The current study aims to provide a comprehensive profile of bioactive metabolites in A. indica aerial parts and its effect against deoxycortisone acetate (DOCA) salt-induced hypertension in Wistar rats. Powdered aerial parts of A. indica were extracted by ultrasonication using methanol as solvent. The methanol extract was fractionated by silica gel vacuum liquid chromatography to obtain n-hexane fraction and methanol fraction designated as AIMF. The phytochemical constituents of AIMF were analysed using High Resolution-Liquid Chromatography-Mass Spectrometry (HR-LC-MS) performed in an LC-ESI-Q-TOF-MS system (Agilent Technologies 6550 i-Funnel). Mass analysis was conducted using the ESI-positive ionization mode. Hypertension was induced in uninephrectomised rats by injecting DOCA (25 mg/kg bw) in 1% NaCl into drinking water. Hypertensive rats were then treated with AIMF (200 mg/kg and 400 mg/kg, p.o) once daily for one week. HR-LC-MS analysis identified 52 compounds in AIMF with beta-D-gentiobiosylcrocetin, maritimetin, kaempferol-4'-glucoside-7-rhamnoside, quercetin, rutin, and isoamyl nitrite as the major compounds. AIMF at 400 mg/kg resulted in a significant reduction in the mean systolic and diastolic blood pressure in hypertensive rats with concomitant reduction in renal function parameters (urea, uric acid, and creatinine) and liver function enzymes (aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase), as well as an increase in antioxidant enzymes particularly superoxide dismutase (SOD). The key metabolites of AIMF especially those with vasodilatory effect may be responsible for its antihypertensive effect, and play a role in the renoprotective and hepatoprotective effects.