title: Isolation of an angiotensin converting enzyme (ACE) inhibitor from Olea europaea and Olea lancea.
abstract: The aqueous extract of the leaves of Olea europaea and Olea lancea both inhibited Angiotensin Converting Enzyme (ACE) in vitro. A bioassay-directed fractionation resulted in the isolation of a strong ACE-inhibitor namely the secoiridoid 2-(3,4-dihydroxyphenyl)ethyl 4-formyl-3-(2-oxoethyl)-4 E-hexenoate (oleacein) (IC(50) = 26 μM). Five secoiridoid glycosides (oleuropein, ligstroside, excelcioside, oleoside 11-methyl ester, oleoside) isolated from Oleaceous plants showed no significant ACE-inhibition whereas, after enzymatic hydrolysis, the ACE-inhibition at 0.33 mg/ml was between 64% to 95%. Secoiridoids have not been described previously in the literature as inhibitors of ACE. Oleacein showed a low toxicity in the brine shrimp (Artemia satina) lethality test (LC(50) (24 h) = 969 ppm).
authors.affiliation: Department of Pharmacognosy, The Royal Danish School of Pharmacy, Universitetsparken 2, DK-2100 Copenhagen Ø, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Hansen
authors.forename: A
authors.initials: A
authors.lastname: Adsersen
authors.forename: S B
authors.initials: SB
authors.lastname: Christensen
authors.forename: S R
authors.initials: SR
authors.lastname: Jensen
authors.forename: U
authors.initials: U
authors.lastname: Nyman
authors.forename: U W
authors.initials: UW
authors.lastname: Smitt