Evaluation of bioactive saponins and triterpenoidal aglycons for their binding properties on human endothelin ET_A and angiotensin AT₁ receptors

Abstract

Different types of triterpenes including saponins and aglycons were evaluated for their ability to inhibit [ 3 H] BQ-123 and [3 H] angiotensin II binding to the human endothelin 1 ET A and angiotensin II AT 1 receptors, respectively. Selectivity for only one of the two receptors was exhibited by asiatic acid and its saponins (ET A ) and oleanolic acid (AT 1 ). To a lesser extent betulinic acid, β β β β β-amyrin and friedelin also showed selectivity for the ET A receptor. To address the question whether the effect of saponins on cell membranes might interfere with the normal binding of specific radioligands to their receptors, the activity of saponins with different haemolytic properties were compared. Highly haemolytic saponins such as α α α α α-hederin and β β β β β-escine showed partial (60%) inhibition of radioligand-binding to the ET A receptor and complete inhibition (100%) to the AT 1 receptor. Moreover, the haemolytically inactive kryptoescine, at the same concentration, caused complete inhibiton of radioligand-binding to both receptors, indicating that inhibition of receptor binding was not related to the membrane-interacting properties of saponins.

The Ameliorative Effect of 23-Hydroxytormentic Acid Isolated from Rubus coreanus on Cisplatin-Induced Nephrotoxicity in Rats

“…19) We previously isolated NIF 1 from the butanol extract of Rubus coreanus and hydrolyzed it to produce the aglycon 23-HTA, 21) because aglycones are more active than their corresponding glycosides, though not always. 36) In the present study, we compared the protective effects of the triterpenoid glycoside NIF 1 and its aglycone 23-HTA in rats exposed to acute cisplatin-induced nephrotoxicity by measuring improvements in biochemical parameters and assessing renal tissue damage amelioration observed by histopathological examination.…”

23-Hydroxytormentic Acid and Niga-Ichgoside F1 Isolated from Rubus coreanus Attenuate Cisplatin-Induced Cytotoxicity by Reducing Oxidative Stress in Renal Epithelial LLC-PK1 Cells

“…29) In this study, we compared the inhibitory effects of triterpenoid glycoside NIF 1 and its aglycone 23-HTA on cisplatin-induced cytotoxicity and sought to characterize their antioxidant effects. We found that 23-HTA is a cytoprotective as well as NIF 1 by modulating the antioxidant enzymes to reduce oxidative stress.…”

Triterpene-based plant defenses

“…This study was supported by the molecular similarities between the silphinene antifeedant and the GABA antagonist picrotoxinin, and by silphinene activity on mammalian and insect CNS preparations (Bloomquist 2001(Bloomquist , 2003Bloomquist et al 2008;González-Coloma et al 2002a;Mullin et al 1997). Furthermore, betulinic acid (5) binds angiotensine I and muscarinic receptors (Zhu et al 1996), while triterpene acids such as oleanolic acid (9) and b-glycyrrhetinic acid are angiotensin blockers (Caballero-George et al 2004). Betulin (3) binds GABA-A receptor sites in mice brain in vitro and has CNS activity in vivo (Muceniece et al 2008).…”

“…Angiotensin blockers, including triterpene such as oleanolic and b-glycyrrhetinic acids, induced ecdysteroid secretion in the lepidopteran Lymantria dispar (Caballero-George et al 2004;Loeb et al 1998), suggesting that these triterpenes could interfere with the insect's ecdysteroid levels. Triterpenes such as oleanolic and ursolic acids have fluidity-modulating effects on liposomal membranes (Han et al 1997).…”