title: Activity-guided discovery of (S)-malic acid 1'-O-β-gentiobioside as an angiotensin I-converting enzyme inhibitor in lettuce (Lactuca sativa).
abstract: Angiotensin-converting enzyme (ACE), playing a crucial role in the renin angiotensin aldosterone system, is well-known to catalyze the conversion of the decapeptide angiotensin I into the physiologically active octapeptide angiotensin II, triggering blood pressure increasing mechanisms. To meet the demand for natural phytochemicals as antihypertensive agents in functional food development, extracts prepared from a series of vegetables were screened for their ACE-inhibitory activity by means of a LC-MS/MS-based in vitro assay. By far the highest ACE inhibition was found for a lettuce extract, in which the most active compound was located by means of activity-guided fractionation. LC-MS, NMR spectroscopy, and hydrolysis experiments followed by ion chromatography led to the unequivocal identification of the ACE inhibitor as the previously not reported (S)-malic acid 1'-O-β-gentiobioside. This glycoside represents a novel class of ACE-inhibiting phytochemicals with a low IC(50) value of 27.8 μM. First incubation experiments in saliva and aqueous hydrochloric acid demonstrated the stability of (S)-malic acid 1'-O-β-gentiobioside against salivary glycosidases and stomach acid.
authors: Chair of Food Chemistry and Molecular Sensory Science, Technische Universität München, Lise-Meitner-Strasse 34, D-85354 Freising-Weihenstephan, Germany.
authors: Annika
authors: A
authors: Lagemann
authors: Andreas
authors: A
authors: Dunkel
authors: Thomas
authors: T
authors: Hofmann
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors / Q000032:analysis* / Q000494:pharmacology*; D000959:Antihypertensive Agents; D004355:Drug Stability; D055951:Functional Food / Q000032:analysis; D006027:Glycosides / Q000032:analysis* / Q000494:pharmacology*; D018545:Lactuca / Q000737:chemistry*; D008293:Malates / Q000032:analysis* / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry; D012463:Saliva; D014675:Vegetables / Q000737:chemistry
chemical_list: C576323:(S)-malic acid 1'-O-beta-gentiobioside; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D006027:Glycosides; D008293:Malates; D010936:Plant Extracts