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Fulltext Effects of Root Extracts of Eurycoma longifolia Jack on Corpus Cavernosum of Rat

Tee BH, Hoe SZ, Cheah SH, Lam SK

Med Princ Pract, 2017;26(3):258-265.
PMID: 28226311 DOI: 10.1159/000464363

OBJECTIVE: This study was conducted to investigate the mechanisms of action of Eurycoma longifolia in rat corpus cavernosum.
MATERIALS AND METHODS: Tincture of the roots was concentrated to dryness by evaporating the ethanol in vacuo. This ethanolic extract was partitioned into 5 fractions sequentially with hexane, dichloromethane (DCM), ethyl acetate, butanol, and water. The corpus cavernosum relaxant activity of each fraction was investigated. The DCM fraction which showed the highest potency in relaxing phenylephrine-precontracted corpora cavernosa was purified by column chromatography. The effects of the most potent DCM subfraction in relaxing phenylephrine-precontracted corpora cavernosa, DCM-I, on angiotensin I- or angiotensin II-induced contractions in corpora cavernosa were investigated. The effects of DCM-I pretreatment on the responses of phenylephrine-precontracted corpora cavernosa to angiotensin II or bradykinin were also studied. An in vitro assay was conducted to evaluate the effect of DCM-I on angiotensin-converting enzyme activity.
RESULTS: Fraction DCM-I decreased the maximal contractions (100%) evoked by angiotensin I and angiotensin II to 30 ± 14% and 26 ± 16% (p < 0.001), respectively. In phenylephrine-precontracted corpora cavernosa, DCM-I pretreatment caused angiotensin II to induce 82 ± 27% relaxation of maximal contraction (p < 0.01) and enhanced (p < 0.001) bradykinin-induced relaxations from 47 ± 8% to 100 ± 5%. In vitro, DCM-I was able to reduce (p < 0.001) the maximal angiotensin-converting enzyme activity to 78 ± 0.24%.
CONCLUSION: Fraction DCM-I was able to antagonize angiotensin II-induced contraction to cause corpus cavernosum relaxation via inhibition of angiotensin II type 1 receptor and enhance bradykinin-induced relaxation through inhibition of angiotensin-converting enzyme.

Matched MeSH terms: Peptidyl-Dipeptidase A/drug effects
ACE2 activation by xanthenone prevents leptin-induced increases in blood pressure and proteinuria during pregnancy in Sprague-Dawley rats

Ibrahim HS, Froemming GR, Omar E, Singh HJ

Reprod Toxicol, 2014 Nov;49:155-61.
PMID: 25205467 DOI: 10.1016/j.reprotox.2014.08.006

This study investigates the effect of ACE2 activation on leptin-induced changes in systolic blood pressure (SBP), proteinuria, endothelial activation and ACE2 expression during pregnancy in Sprague-Dawley rats. Pregnant rats were given subcutaneous injection of either saline, or leptin, or leptin plus xanthenone (ACE2 activator), or xanthenone (XTN) alone. SBP, serum ACE, ACE2, endothelin-1, E-selectin and ICAM-1 levels were estimated; also their gene expressions were determined in the kidney and aorta respectively. Compared to control, SBP was higher in the leptin-only treated group (P<0.001) and lower in rats treated with xanthenone alone (P<0.01). Proteinuria, markers of endothelial activation were significantly higher than controls in leptin-only treated rats (P<0.05). ACE2 activity and expression were lower in leptin-only treated rats when compared to controls (P<0.05). It seems, leptin administration during pregnancy significantly increases SBP, proteinuria, endothelial activation, but decreases ACE2 level and expression. These effects are prevented by concurrent administration of xanthenone.

Matched MeSH terms: Peptidyl-Dipeptidase A/drug effects*
Metabolites of the ellagitannin, geraniin inhibit human ACE; in vitro and in silico evidence

Looi D, Goh BH, Khan SU, Ahemad N, Palanisamy UD

Int J Food Sci Nutr, 2021 Jun;72(4):470-477.
PMID: 33032478 DOI: 10.1080/09637486.2020.1830263

Hypertension is defined as the persistence of elevated blood pressure in the circulation system. The renin-angiotensin-aldosterone system is a major modulator of blood pressure. Among the risk factors of cardiovascular disease, hypertension is the most preventable and treatable, with drugs such as ACE inhibitors. Many ACE inhibitors are known to have undesirable side effects and hence, natural alternatives are being sought. Dietary polyphenols, particularly ellagitannins, are derived from plant products and are known to exhibit a variety of bioactivities. Geraniin, an ellagitannin has been shown to have antihypertensive activity in animal experiments. It is speculated that the metabolites of geraniin are responsible for its ACE inhibitory activity. We have performed in vitro ACE inhibition and in silico studies with geraniin and its metabolites (ellagic acid, urolithins). Our studies confirm that ellagic acid exhibited similar inhibitory potential to ACE as the positive control captopril.

Matched MeSH terms: Peptidyl-Dipeptidase A/drug effects
Fulltext In vitro inhibitory potential of selected Malaysian plants against key enzymes involved in hyperglycemia and hypertension

Loh SP, Hadira O

Malays J Nutr, 2011 Apr;17(1):77-86.
PMID: 22135867 MyJurnal

This study was conducted to determine the inhibitory potential of selected Malaysian plants against key enzymes related to type 2 diabetes and hypertension.

Matched MeSH terms: Peptidyl-Dipeptidase A/drug effects