Comparison of the antihypertensive effect of maguey (Agave salmiana) sap concentrate extracts by in vitro and in vivo tests

Abstract

Introduction: The use of antihypertensive drugs causes side effects that lead to treatment discontinuation; therefore, plants containing polyphenols and saponins represent a viable alternative. Previous studies indicate that maguey sap concentrate (SC) contains these bioactive compounds. The objective of this study was to compare the antihypertensive effect of maguey SC extracts through in vitro and in vivo tests.

Methods: In the in vitro study, angiotensin-converting enzyme (ACE) inhibition was measured with butanolic and methanolic extracts of SC (100-250 ppm). For the in vivo tests, 48 male Wistar rats were divided into 6 groups: negative control (C), positive control (E): enalapril (25 mg/kg/day), BE1 and BE2: butanolic extracts (250 and 500 mg/kg/day) and ME1 and ME2: methanolic extracts (500 and 750 mg/kg/day). Their blood pressure was measured once a week for 28 days. In addition, blood samples were taken to determine glucose, creatinine, C-reactive protein, cholesterol, sodium potassium, calcium, and platelet count. At the end of the experiment, the animals were sacrificed, and their livers, kidneys, and hearts were preserved for histopathological analysis.

Results: Both extracts showed ACE inhibition greater than 90%. All treatments, except C, showed a decrease in blood pressure at 28 days; however, the ME2 treatment had an effect like that of enalapril (P>0.05). Blood test results showed an increase in glucose levels, although within normal parameters, C-reactive protein levels are outside or above the maximum allowed limit except in those treated with enalapril. This research demonstrates for the first time the antihypertensive effect of methanolic and butanolic extracts obtained from maguey sap concentrate, opening the possibility of using them in the production of functional foods, as well as promoting the production and consumption of maguey sap, adding value to this natural resource.

Conclusion: The results of this study introduce the possibility of further exploring the bioactive compounds in aguamiel concentrate. Although the methanolic extract was able to lower blood pressure, it should only be considered as an adjunct to pharmacological treatments, and the possible toxicological effect of the extracts in the long term should be explored in greater detail.

Keywords: hypertension; sap; aguamiel; agave; saponins; antioxidants