Monoamine Oxidase-A Inhibition and Associated Antioxidant Activity in Plant Extracts with Potential Antidepressant Actions
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Hindawi BioMed Research International Volume 2018, Article ID 4810394, 10 pages https://doi.org/10.1155/2018/4810394 Research Article Monoamine Oxidase-A Inhibition and Associated Antioxidant Activity in Plant Extracts with Potential Antidepressant Actions Tomás Herraiz and Hugo Guillén Instituto de Ciencia y Tecnolog´ıa de Alimentos y Nutricion(ICTAN),SpanishNationalResearchCouncil(CSIC),´ Juan de la Cierva 3, 28006 Madrid, Spain Correspondence should be addressed to Tomas´ Herraiz; [email protected] Received 3 August 2017; Accepted 12 December 2017; Published 15 January 2018 Academic Editor: Pierluigi Di Ciccio Copyright © 2018 Tomas´ Herraiz and Hugo Guillen.´ Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Monoamine oxidase (MAO) catalyzes the oxidative deamination of amines and neurotransmitters and is involved in mood disorders, depression, oxidative stress, and adverse pharmacological reactions. Tis work studies the inhibition of human MAO-A by Hypericum perforatum, Peganum harmala, and Lepidium meyenii, which are reported to improve and afect mood and mental conditions. Subsequently, the antioxidant activity associated with the inhibition of MAO is determined in plant extracts for the frst time. H. perforatum inhibited human MAO-A, and extracts from fowers gave the highest inhibition (IC50 of 63.6 �g/mL). Plant extracts were analyzed by HPLC-DAD-MS and contained pseudohypericin, hypericin, hyperforin, adhyperforin, hyperfrin, and favonoids. Hyperforin did not inhibit human MAO-A and hypericin was a poor inhibitor of this isoenzyme. Quercetin and favonoids signifcantly contributed to MAO-A inhibition. P. har mal a seed extracts highly inhibited MAO-A (IC50 of 49.9 �g/L), being a thousand times more potent than H. perforatum extracts owing to its content of �-carboline alkaloids (harmaline and harmine). L. meyenii root (maca) extracts did not inhibit MAO-A. Tese plants may exert protective actions related to antioxidant efects. Results in this work show that P. har mal a and H. perforatum extracts exhibit antioxidant activity associated with the inhibition of MAO (i.e., lower production of H2O2). 1. Introduction Recent investigations have pointed out that plant and food extracts may inhibit MAO enzymes resulting in the above- Te enzyme monoamine oxidase (MAO) metabolizes xen- mentioned biological efects [3, 5–14]. On the other hand, as obiotic and endogenous amines and neurotransmitters a result of MAO inhibition, those products might be involved including serotonin, dopamine, norepinephrine, tyramine, in undesirable interactions with other herbal preparations, tryptamine, and the neurotoxin MPTP [1, 2]. It occurs as two foods, or drugs [1]. isoenzymes, MAO-A and MAO-B, which play an important Hypericum perforatum L. (family Hypericaceae) (St. role in the central nervous system (CNS) and peripheral John’s wort) is widely used for health purposes and their organs. MAO-B is involved in neurodegenerative diseases products are commercially available as herbs, nutraceuticals, and MAO-A in psychiatric conditions and depression. teas, tinctures, juices, oily macerates, phytopharmaceuticals, Inhibitors of MAO-B are useful as neuroprotectants, whereas and food additives and supplements [15, 16]. H. perforatum is inhibitors of MAO-A are efective antidepressants although popular for treatment of mild and moderate depression [17– their use may trigger adverse reactions (e.g., hypertensive 19]. It may trigger adverse pharmacological interactions with crisis with foods containing tyramine) [1]. On the other hand, others herbs, drugs, or foods [20–22]. Its ability to alleviate the oxidation of biogenic amines and neurotransmitters and improve mood disorders and depression is attributed to by MAO enzymes generates hydrogen peroxide (H2O2), active compounds that exhibit antidepressant properties [23, oxygen radicals, and aldehydes, which are risk factors for cell 24]. Te most accepted mechanism of action is monoamine oxidative injury. Terefore, the inhibition of MAO may result reuptake inhibition but additional mechanisms including in protection against oxidative stress and neurotoxins [1, 3, 4]. monoamine oxidase inhibition and synergistic efects can 2 BioMed Research International be involved [17]. Peganum harmala (family Zygophyllaceae) 1050 (Agilent) coupled with a 1100 diode array detector and Lepidium meyenii (family Brassicaceae) (maca) are plants (DAD) (Agilent) and a 1046A-fuorescence detector. A 150 × with CNS efects and potential antidepressant actions [14, 3.9 mm i.d.,4�m, Nova-pak C18 column (Waters) was used 25, 26]. P. har mal a , native from the Mediterranean region for separation. Chromatographic conditions were 50 mM and Asia and extended to North America areas, is used ammonium phosphate bufer (pH 3) (bufer A) and 20% of as a multipurpose health remedy including CNS disorders. A in acetonitrile (bufer B). Te gradient was programmed Preparations of this plant may trigger adverse pharmaco- from 0% (100% A) to 32% B in 8 min and 100% B at 10 min. logical interactions [27]. L. meyenii is an edible plant from Te fow rate was 1 mL/min, the column temperature was ∘ the central Andes whose roots are used as a food energizer 40 C, and the injection volume was 20 �L. Detection of and nutraceutical to improve physical and mental conditions hypericins was carried out by absorbance at 590 nm and andfertility[28].Tepurposeofthisworkwastostudythe fuorescenceat236nmforexcitationand592nmforemis- inhibition of human MAO-A by extracts of H. perforatum, sion. Te concentration of hypericin was determined from a P. har mal a , and L. meyenii (maca) as well as by their active calibration curve of response (absorbance at 590 nm) versus components that were identifed and analyzed by HPLC- concentration with solutions made in the laboratory from DAD-MS and subsequently evaluate the antioxidant activity hypericin standard. Te same response factor was applied which is specifcally associated with the inhibition of MAO. to pseudohypericin, protohypericin, and protopseudohyper- Tis specifc antioxidant activity is determined for the frst icin. Flavonoids and favonoid glycosides were analyzed at time in plant extracts. 265 nm and 355 nm and the concentration of quercetin was determined at 355 nm from a calibration curve of response 2. Materials and Methods versus concentration. Te HPLC fraction corresponding to favonoids and favonoid glycosides (7 to 11 min) was Hypericum perforatum L.plantscollectedinCiudadReal collected by successive injections of H. perforatum extract (Spain) were dried and separated in parts: fowers; top aerial (herbs) and, afer evaporation in vacuum, dissolved in 30% portions of the plant including branched stems and leaves but methanol and used for MAO-A inhibition. Te phlorogluci- no fowers; and main stems (central and lower) and roots. nols (hyperforin, adhyperforin, hyperfrin, and adhyperfrin) Tey were ground and the powder used for sample prepa- wereanalyzedat280nmbyusingthesamecolumn(Nova- ration. Commercial herbs and herbal supplements (capsules pak C18) and conditions but under isocratic elution with and tablets) of H. perforatum were also purchased in local 20% of 50 mM ammonium phosphate bufer, pH 3, and 80% herbal shops. Peganum harmala L. plant and seeds were of acetonitrile. Te concentration of these compounds was collectedinToledo(Spain).Lepidium meyenii (maca) both determined from a calibration curve of hyperforin standard. as powder and commercial tablets were obtained from Peru Te analysis of �-carboline alkaloids in P. har mal a and L. and local shops. Hypericin standard (>95% purity by HPLC) meyenii wascarriedoutaspreviouslydescribed[14,29]. from HWI Analytik GMBH pharma solutions, hyperforin dicyclohexylammonium salt, quercetin, harmaline, harmine, � � 2.3. Identifcation by HPLC-ESI-Mass Spectrometry. Identi- catalase, clorgyline, 3,3 ,5,5 -tetramethylbenzidine (TMB), fcation of compounds in H. perforatum extracts was done and horseradish peroxidase (HRP) type II were purchased by HPLC-MS (electrospray-negative ion mode) by using a from Sigma-Aldrich. 1200 series HPLC-DAD coupled to a 6110 quadrupole-MS (Agilent). Chromatographic separation was performed on a 2.1. Sample Preparation of Plant Extracts. Samples containing 150 × 2.1 mm i.d. Zorbax SB-C18 (5 �m) column (Agilent H. perforatum (i.e., plant parts, herbal preparation, cap- Technologies). Te chromatographic conditions were eluent sules, or tablets) (500 mg) were homogenized in 10 mL of A: formic acid (0.1%); B: formic acid (0.1%) in acetonitrile; water/methanol (1 : 1) by using an Ultra Turrax homogenizer, gradient:0%to70%Bin8minand100%Bat10min, ∘ centrifuged at 10000 rpm for 10 min, and the supernatant was fow rate: 0.3 mL/min; �:40C; mass range: 50–700 u, and collected. Te process was repeated twice with the residue and cone voltage: 150 V. For identifcation of phloroglucinols the three supernatant fractions collected, mixed and analyzed (e.g., hyperforin), separation was done using a Nova-pak by HPLC as mentioned below. Afer three consecutive extrac- C18 (4 �m)columnwiththesameeluentsandisocratic tions, the recoveries of hypericin and pseudohypericin were elution (eluent A, 20% and eluent B, 80%) at a fow rate higher than 97%. Samples of L. meyenii (maca) (500 mg) and of 0.7 mL/min and mass spectra recorded in negative and P. har mal a seeds (500 mg) were homogenized, respectively,