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Angiotensin-converting enzyme inhibition by certain fruits: An in vitro study

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Abstract

Angiotensin-converting enzyme (ACE) (EC 3.4.15.1) is a nonspecific dipeptidyl-carboxypeptidase that converts angiotensin I into a potent vasoconstricting, hypertensive angiotensin II. Inhibition of ACE results in an overall antihypertensive effect and several drugs are currently in use to inhibit the ACE activity such as captopril, enalapril etc. Purpose of the study was to determine the efficacy of Indian Gooseberry, Guava, Wood Apple and Star fruit for angiotensin converting enzyme (ACE) inhibitory activity using Hippuryl-L-histidyl-L-leucine (HHL) as a substrate. An in vitro study was carried out using sheep lung as an enzyme source and both dialyzed and undialyzed fruit extracts were used for testing their ability to reduce the ACE activity. The study revealed that both undialyzed and dialyzed extracts of all four fruits exhibited ACE inhibitory activity which could be due to the varied amounts of phytoconstituents present in the extracts (i. e., phenols, flavanoids, ascorbic acid and protein contents).

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... The authors suggested that the inhibitory activity is owing to the presence of polyphenols and flavonoids linked with the mucilage. The foremost mechanism consists of inhibition of the synthesis of hepatic-3-hydroxy-3-methylglutaryl-Coenzyme-A which regulates the cholesterol synthesis 62 . Thus, the results are evidence of the potential of the natural product as an inexpensive and safe approach for cardioprotection/ hypertension. ...
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The valorization of new polymer sources from underutilized plants as structuring, encapsulating, and texturizing agents for food and nutraceutical applications is gaining attention. This provides an opportunity where inexpensive plant-sourced biopolymers can play an impactful role, on both ecological and economic aspects performing equivalently effectual yet cost-effective substitutes to synthetic polymers. With this aim, we explored the use of mucilage from Althea rosea and reveal its physicochemical, in vitro antidiabetic and antihypertensive activity. Besides, structural, micrometric, crystallization, and anti-microbial properties was also seen. We determined the probable structure of the extracted mucilage by FTIR which confirmed the residues of saccharides as galactose and uronic acid with α and β configurations. It consists of 78.26% carbohydrates, 3.51% ashes, and 3.72% proteins. Here, we show that the mucilage offered protection to DNA against the oxidative damage caused by (-OH) radicals and the morphology of the mucilage particles displayed a fibrillary material settled in a net-like, tangled structure. Our results demonstrate that the reconstituted mucilage powder exhibited good water holding capacity (2.89 g water/g mucilage), solubility (27.33%), and oil holding capacity (1.79 g oil/g mucilage). Moreover, high emulsifying property (95.83%) and foaming capacity (17.04%) was noted. Our results indicate that A.rosea mucilage can potentially serve as economical and eco-friendly hydrocolloid substitute for the food and nutraceutical industry owing to its functional, hypo-lipidemic, anti-hyperglycemic, antioxidant, and anti-bacterial properties.
... Nowadays, scientists believe the effect of oxidative stress on blood pressure [28,29], and EO can be effective in the prevention or treatment of hypertension through its strong antioxidative properties [30]. More importantly, EO is a plant with the ACE (angiotensin-converting enzyme) inhibitor and diuretic activity which can explain its antihypertensive effect [31,32]. e strength of the present study was the triple-blind design and checking the medication adherence. ...
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Introduction. Emblica officinalis (EO) has some cardiovascular effects, and there are some animal studies that show its antihypertensive effect. This study was conducted to determine the effect of combination of EO with standard therapy on the systolic blood pressure (SBP) and diastolic blood pressure (DBP) in patients with uncontrolled hypertension. Materials and Methods. This was a randomized, triple-blind, placebo-controlled, 8-week study. Ninety-two patients with uncontrolled hypertension despite taking hypotensive drugs were randomly assigned into two groups to take EO (500 mg/TDS after meal) or placebo in combination with standard antihypertensive drugs. After 2, 4, 6, and 8 weeks of intervention, SBP and DBP and heart rate (HR) were measured. Data were analyzed by SPSS software using repeated measures ANOVA. Results. Eighty-one patients (41 in the drug group and 40 in the placebo group) completed the study for 8 weeks and were analyzed. The mean ± standard deviation of age was 53.64 ± 10.01 years. SBP decreased as 15.6 ± 8.23% in the EO group and 6.3 ± 7.49% in the placebo group (P < 0.001). DBP decreased as 12.3 ± 7.87% and 3.88 ± 7.98%, respectively (P < 0.001). Time effect was not significant, but the group effect was significant (F = 13.875, P=0.001 for systolic BP and F = 18.948, P < 0.001 for diastolic BP). No side effects were reported during the study. Conclusion. Eight-week combination therapy of EO with standard antihypertensive drugs significantly reduced the SBP and DBP more than placebo in patients with uncontrolled hypertension.
... All herbal extracts were estimated at the dose of 10mg/ml ( Narasimhacharya et al. (2010), who suggested that the activity was directly related to the quantity of flavonoids, polyphenols, phenolic acids, protein and ascorbic acid content of the herb extract. ACE inhibitory activity of tulsi reported as 21% in aqueous extract by Nymen et al. (1998), while for ashwagandha it was in range of 11-22%, depending on type of extract used. ...
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Some herbal bioactives possess high antioxidant and angiotensin converting enzymes (ACE) inhibition activity, which affects blood pressure levels. Herbal bioactives promote health benefits via different molecular mechanisms and most of these mechanisms are yet to be fully elucidated. In the present study, health promoting potential of aqueous extracts of six herbs viz. Allium sativum L., Withania somnifera (L.) Dunal, Ocimum sanctum L., Hibiscus sabdriffa L., Ginkgo biloba L. and Emblica officinalis at different concentrations (50 to 10,000 μg/mL) were assessed through their antioxidant and ACE inhibitory potential. Results showed that the DPPH (2, 2-diphenyl-1-picrylhydrazyl) activity of the six different herbs ranged from 1.58 ± 0.63 to 11.39 ± 0.15 mM/mL trolox equivalent and was in the order of Emblica officinalis >Withania somnifera >Hibiscus sabdriffa >Ginkgo biloba >Ocimum sanctum =Allium sativum at 1000 μg/mL concentration. Emblica officinalis had IC50 value 180.35 ± 1.17 μg/mL. The corresponding observation for the herb with 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) was 167.19 ± 1.04 μg/mL. Ferric reducing antioxidant power (FRAP) values were significantly higher for Emblica officinalis than the other herbs, and varied from 1.78 ± 0.08 to 251.62 ± 6.31 mM/mL ascorbic acid equivalent at different concentrations (50 to 10000 μg/mL). Emblica officinalis had the strongest ACE inhibition potential (82.08 ± 5.18 %), followed by Withania somnifera, Hibiscus sabdriffa, Ginkgo biloba, Ocimum sanctum and Allium sativum. ACE inhibitory activity of herbs studied was lower (31.64 ± 5.05 %) than that of Captopril (0.002173 μg/mL), a standard medicine used for hypertension. The study compared and elucidated the antioxidant and ACE inhibitory potential of aqueous extracts of herbs at different concentrations. The study results may be useful in the selection of herbal bioactives for functional foods and aqueous nutraceutical formulations.
... In limited studies in human and murine models , Punica granatum L. (Lythraceae) or pomegranate juice has been shown to exert significant antihypertensive effects [29]. The efficacy of Indian gooseberry (Phyllanthus emblica L.) (Phyllanthaceae), guava (Psidium guajava), wood apple (Limonia acidissima L.) (Rutaceae) and star fruit (Averrhoa carambola L.) (Oxalidaceae) for angiotensin-converting enzyme (ACE) inhibitory activity using hippuryl-L-histidyl-Lleucine as a substrate was determined [30]. S. Das and B. De hypertension. ...
... In limited studies in human and murine models, Punica granatum L. (Lythraceae) or pomegranate juice has been shown to exert significant antihypertensive effects [29]. The efficacy of Indian gooseberry (Phyllanthus emblica L.) (Phyllanthaceae), guava (Psidium guajava), wood apple (Limonia acidissima L.) (Rutaceae) and star fruit (Averrhoa carambola L.) (Oxalidaceae) for angiotensin-converting enzyme (ACE) inhibitory activity using hippuryl-L-histidyl-Lleucine as a substrate was determined [30]. ...
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Ripened and unripened nendran, rasthali, poovan, robusta, bontha and safed velchi bananas were investigated for inhibition against angiotensin converting enzyme (ACE) using Hip-His-Leu as substrate. The inhibition of ACE by different ripened banana cultivars was much more than that of unripened banana cultivars. The ACE inhibitory activity of ripened and unripened poovan was heat stable and stable to extreme acidic pH and alkaline pH. The ACE inhibitory activity of ripened and unripened banana cultivars was reduced to 25% and 33% respectively on dialysis.
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