Antihypertensive Effect of Carica papaya Via a Reduction in ACE Activity and Improved Baroreflex

Abstract

The aims of this study were to evaluate the antihypertensive effects of the standardised methanolic extract of Carica papaya, its angiotensin converting enzyme inhibitory effects in vivo, its effect on the baroreflex and serum angiotensin converting enzyme activity, and its chemical composition. The chemical composition of the methanolic extract of C. papaya was evaluated by liquid chromatography-mass/mass and mass/mass spectrometry. The angiotensin converting enzyme inhibitory effect was evaluated in vivo by Ang I administration. The antihypertensive assay was performed in spontaneously hypertensive rats and Wistar rats that were treated with enalapril (10 mg/kg), the methanolic extract of C. papaya (100 mg/kg; twice a day), or vehicle for 30 days. The baroreflex was evaluated through the use of sodium nitroprusside and phenylephrine. Angiotensin converting enzyme activity was measured by ELISA, and cardiac hypertrophy was evaluated by morphometric analysis. The methanolic extract of C. papaya was standardised in ferulic acid (203.41 ± 0.02 µg/g), caffeic acid (172.60 ± 0.02 µg/g), gallic acid (145.70 ± 0.02 µg/g), and quercetin (47.11 ± 0.03 µg/g). The flavonoids quercetin, rutin, nicotiflorin, clitorin, and manghaslin were identified in a fraction of the extract. The methanolic extract of C. papaya elicited angiotensin converting enzyme inhibitory activity. The antihypertensive effects elicited by the methanolic extract of C. papaya were similar to those of enalapril, and the baroreflex sensitivity was normalised in treated spontaneously hypertensive rats. Plasma angiotensin converting enzyme activity and cardiac hypertrophy were also reduced to levels comparable to the enalapril-treated group. These results may be associated with the chemical composition of the methanolic extract of C. papaya, and are the first step into the development of a new phytotherapic product which could be used in the treatment of hypertension.

Fruits for Prevention and Treatment of Cardiovascular Diseases

“…The result showed that the angiotensin converting enzyme inhibitory effects of papaya (100 mg/kg) were similar to those of enalapril (10 mg/kg). The flavonoids, especially quercetin, rutin, nicotiflorin, clitorin, and manghaslin, were identified as bioactive components of the extract, which could be applied to the treatment of hypertension [12]. In addition, several studies revealed that cherry, Guangzao ( Choerospondias axillaris ), and acai ( Euterpe oleracea Mart.)…”

“…Nevertheless, drugs are not effective on all patients and have side effects that may aggravate the patients’ symptoms and signs. Some fruits (extract) possess similar or even more potent anti-hypertensive, lipid-lowering, and hypoglycemic activities, which has inspired many researchers to explore new therapies for CVDs [9,10,11,12]. The cardioprotective mechanisms of fruits are not entirely clear, but their outstanding antioxidant and free radical scavenging properties are considered principal [13].…”

Low dose of methyltestosterone in ovariectomised rats improves baroreflex sensitivity without geno‐ and cytotoxicity

“…The rats were anaesthetized with ketamine/xylazine (110/10 mg/kg, i.p.) as demonstrated in Brasil et al's study , and a PE 50 catheter was placed into the femoral artery and vein, and 24 h later, the MAP and HR were recorded using a pressure transducer (Model PT 300; Grass Instrument Div., Warwick, NY, USA) coupled to a Biopac System (MP100; Santa Barbara, CA, USA) during the 40‐min recording period, according to Franquni et al . The HR was calculated instantaneously from the intervals of pressure pulses.…”

“…100ª/serie 94111065 MP). The relation between the changes in MAP and the respective changes in HR was evaluated by regression according to Brasil et al . The regression coefficient (slope of the curve) expressed as beats per minute (bpm/mmHg) was used as the baroreflex sensitivity index of phenylephrine (BRSPHE) or sodium nitroprusside (BRSNP) .…”

“…Cardiovascular reflexes are important mechanisms involved in the control of cardiac function and vascular resistance and maintenance of blood pressure levels . In previous work, our group and others demonstrated the importance and influence of the sensitivity of the baroreflex (BRS) and the Bezold–Jarisch reflex (BJR) on the cardiovascular system control .…”