A Comparative Study of the Antihypertensive and Cardioprotective Potentials of Hot and Cold Aqueous Extracts of Hibiscus sabdariffa L. in Relation to Their Metabolic Profiles

Abstract

Ethnopharmacological relevance: Since ancient times, Hibiscus sabdariffa L. calyces have been used as a folk remedy for the treatment of hypertension. However, it is questionable as to whether there is a difference in the antihypertensive activity of the hot or cold aqueous extracts.Aim of the study: We designed this study to specify the best method for water extraction of the antihypertensive metabolites of H. sabdariffa and to confirm their in vivo antihypertensive capabilities.Materials and methods: The powdered dried calyces of H. sabdariffa were independently extracted with cold and hot water. A comparative study was performed between the cold and hot aqueous extracts of H. sabdariffa based on evaluation of the in vitro renin and angiotensin-converting enzyme (ACE) inhibition activities. Additionally, both extracts were subjected to an in vivo study for the evaluation of their antihypertensive activities in L-Nw-Nitro arginine methyl ester (L-NAME)–induced hypertensive rats. Further, a metabolomics study was also performed for both extracts to identify their chemical constituents.Results: The cold and hot extracts significantly reduced the angiotensin II, ACE, and aldosterone levels in the plasma. Furthermore, in the myocardium and aorta, decreased iNOS (inducible nitric oxide synthase) levels and elevated eNOS (endothelial nitric oxide synthase), as well as the rise in plasma NO levels, were reported with both extracts, but better results were displayed with the hot extract, leading to a potential antihypertensive effect. Additionally, the cold and hot Hibiscus extracts induced a cardioprotective effect through reducing necrosis, inflammation, and vacuolization that results from the induction of hypertension, an effect that was more prominent with the hot extract. Moreover, a comprehensive metabolomics approach using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC–MS/MS) was able to trace the metabolites in each extraction.Conclusion: The extracts showed different anthocyanin and phenolic compounds, but the hot extract showed higher contents of specific phenolics to which the superior antihypertensive and cardioprotective activities could be related.

Hibiscus attenuates renovascular hypertension–induced aortic remodeling dose dependently: the oxidative stress role and Ang II/cyclophilin A/ERK1/2 signaling

“…Several antihypertensive mechanisms are linked to the actions of HS. HS could exert diuretic and vasodilating activities, and inhibition of angiotensin converting enzyme ( Salem et al, 2022 ). Our data reported the influence of HS on controlling arterial blood pressure.…”

Tortillas made from nixtamalized maize and extruded chickpea flours: A product with improved in vitro nutritional and antihypertensive properties

“…But, the relevance of in vitro ACE inhibition seems more difficult to extrapolate to the in vivo situation. However, the physiological effects of ACE inhibition on hypertension can be inferred from the high values of bioaccessibility and bioavailability of phenolic compounds as well as from in vivo ACE inhibition results of them that have been reported in the literature (Häckl et al, 2002; Kasprzak‐Drozd et al, 2021; Salem et al, 2022). However, more research is needed in the future to obtain information regarding the components of ingested functional foods or functional food ingredients that will reach ACE in serum, lungs, and kidneys to inhibit it and thus reduce blood pressure.…”

In-vitro antiviral activity of Carica papaya formulations against dengue virus type 2 and chikungunya virus

“…PL was prepared by heat treatment with water. It has been reported that heat treatment with water leads to extraction of more amount of total phenolics which might have contributed to the cytotoxicity observed with PL [ 23 ]. The study revealed among the four formulations, silver nanoparticles based on PLE (PNP) and Papaya extract prepared using a SF extraction machine (PE) showed activity against DENV -2 virus under all conditions though the effect was more pronounced in post infection treatment conditions.…”

“…Cytotoxic effect of papaya formulations (commercial and plant material formulations) on Vero CCL-81 cells were evaluated using 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay [ 23 ]. Briefly, Vero cells were incubated with different concentrations of test formulations (0–200 μg/ml) at 37°C for 5 days.…”