title: Monoamine oxidase inhibition by monoterpene indole alkaloids and fractions obtained from Psychotria suterella and Psychotria laciniata.
abstract: Alkaloid fractions of Psychotria suterella (SAE) and Psychotria laciniata (LAE) as well as two monoterpene indole alkaloids (MIAs) isolated from these fractions were evaluated against monoamine oxidases (MAO-A and -B) obtained from rat brain mitochondria. SAE and LAE were analysed by HPLC-PDA and UHPLC/HR-TOF-MS leading to the identification of the compounds 1, 2, 3 and 4, whose identity was confirmed by NMR analyses. Furthermore, SAE and LAE were submitted to the enzymatic assays, showing a strong activity against MAO-A, characterized by IC(50) values of 1.37 ± 1.05 and 2.02 ± 1.08 μg/mL, respectively. Both extracts were also able to inhibit MAO-B, but in higher concentrations. In a next step, SAE and LAE were fractionated by RP-MPLC affording three and four major fractions, respectively. The RP-MPLC fractions were subsequently tested against MAO-A and -B. The RP-MPLC fractions SAE-F3 and LAE-F4 displayed a strong inhibition against MAO-A with IC(50) values of 0.57 ± 1.12 and 1.05 ± 1.15 μg/mL, respectively. The MIAs 1 and 2 also inhibited MAO-A (IC(50) of 50.04 ± 1.09 and 132.5 ± 1.33 μg/mL, respectively) and -B (IC(50) of 306.6 ± 1.40 and 162.8 ± 1.26 μg/mL, respectively), but in higher concentrations when compared with the fractions. This is the first work describing the effects of MIAs found in neotropical species of Psychotria on MAO activity. The results suggest that species belonging to this genus could consist of an interesting source in the search for new MAO inhibitors.
authors.affiliation: Laboratório Farmacognosia, Departamento de Produção de Matéria Prima, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brasil.
authors.forename: Carolina
authors.initials: C
authors.lastname: Dos Santos Passos
authors.forename: Tatiane Cristina
authors.initials: TC
authors.lastname: Soldi
authors.forename: Renata
authors.initials: R
authors.lastname: Torres Abib
authors.forename: Miriam
authors.initials: M
authors.lastname: Anders Apel
authors.forename: Cláudia
authors.initials: C
authors.lastname: Simões-Pires
authors.forename: Laurence
authors.initials: L
authors.lastname: Marcourt
authors.forename: Carmem
authors.initials: C
authors.lastname: Gottfried
authors.forename: Amélia Teresinha
authors.initials: AT
authors.lastname: Henriques
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology; D002851:Chromatography, High Pressure Liquid; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical / Q000379:methods; D020128:Inhibitory Concentration 50; D008297:Male; D008928:Mitochondria / Q000201:enzymology; D008996:Monoamine Oxidase Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology; D032069:Psychotria / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D046948:Secologanin Tryptamine Alkaloids / Q000737:chemistry* / Q000494:pharmacology*
chemical_list: D008996:Monoamine Oxidase Inhibitors; D010936:Plant Extracts; D046948:Secologanin Tryptamine Alkaloids