Inhibition of monoamine oxidase B (MAO-B) by Chinese herbal medicines

Protective effect of pterostilbene in a streptozotocin-induced mouse model of Alzheimer's disease by targeting monoamine oxidase B

Alzheimer's disease (AD) is a neurodegenerative disease in elderly population. Pterostilbene (PTS) is a resveratrol analogue with neuroprotective activity. However, the biological mechanisms of PTS in AD progression are largely uncertain. An animal model of AD was established using streptozotocin (STZ)-treated C57BL/6J mice. Monoamine oxidase B (MAOB) expression was analyzed by bioinformatics analysis and detected by western blotting assay. The memory impairment was investigated by Morris water maze test. The levels of Tau hyperphosphorylation and death-related proteins were detected by western blotting analysis. The levels of amyloid β (Aβ)_1-42 accumulation, oxidative stress-related markers (ROS, MDA, SOD and GSH), and inflammation-relative markers (TNF-α, IL-1β, IL-6 and p-NF-κB) were measured by ELISA. MAOB expression was increased in hippocampus of AD mice, and it was decreased by PTS. PTS attenuated STZ-induced body weight loss and memory impairment by regulating MAOB. PTS mitigated Aβ_1-42 accumulation and Tau hyperphosphorylation by regulating MAOB in STZ-treated mice. PTS attenuated neuronal death by decreasing cleaved caspase-3 and Bax levels and increasing Bcl2 expression in hippocampus by regulating MAOB in STZ-treated mice. PTS weakened STZ-induced oxidative stress in hippocampus by decreasing ROS and MDA levels and increasing SOD and GSH levels by regulating MAOB. PTS protected against STZ-induced neuroinflammation in hippocampus by inhibiting TNF-α, IL-1β, IL-6 and p-NF-κB levels through regulating MAOB. In conclusion, PTS alleviates STZ-induced memory impairment, Aβ_1-42 accumulation, Tau hyperphosphorylation, neuronal death, oxidative stress and inflammation by decreasing MAOB in AD mice, proving anti-AD potential of PTS.

Anxiolytic and antidepressants' effect of Crataegus pinnatifida (Shan Zha): biochemical mechanisms

Depression and anxiety disorders are highly prevalent. Selective serotonin reuptake inhibitors (SSRIs) are the current first-line treatment for depression, but they have pronounced limitations. Traditional Chinese medicine can serve as a safe and effective alternative to conventional drugs, particularly since many herbal remedies have already been approved for human use as food additives, making the transition from bench to bedside more efficient. We previously demonstrated that a novel herbal treatment (NHT) induces anxiolytic- and antidepressant-like effects. NHT consists of four herbs: Crataegus pinnatifida (Shan Zha), Triticum aestivum (Fu Xiao Mai), Lilium brownii (Baihe), and the fruit of Ziziphus jujuba (Da Zao). In the current study, we examined the antidepressant-like and anxiolytic-like activities of each individual herb on stressed mice and compared those to the effects of NHT and escitalopram. We show here that Shan Zha is sufficient to produce an anxiolytic and antidepressant-like effect similar to NHT or the escitalopram through activation of 5-HT1A receptor and an elevation in BDNF levels in the hippocampus and Pre-frontal cortex (PFC). Chronic treatment with Shan Zha did not alter serotonin transporter levels in the PFC, as opposed to escitalopram treatment. These results were confirmed in vitro, as none of the herbs blocked SERT activity in Xenopus oocytes. Notably, Shan Zha is sold as a nutritional supplement; thus, its transition to clinical trials can be easier. Once its efficacy and safety are substantiated, Shan Zha may serve as an alternative to conventional antidepressants.

Dismantling Parkinson's disease with herbs: MAO-B inhibitory activity and quantification of chemical constituents using HPLC-MS/MS of Egyptian local market plants

Withania somnifera, Angelica sinensis, Glycyrrhiza glabra, and Simmondsia chinensis were acquired from the Egyptian market, profiled for their chemical constituents, screened for the in-vitro MAO-B inhibitory activity and evaluated for the total phenolic content. Thirty compounds were characterized in the selected herbs using HPLC-MS/MS. In-vitro MAO-B inhibitory activity and total phenolic content of the acquired herbs were compared with those of a prepared herbal formula consisting of a mixture of equal amounts of the four mentioned herbs. The most potent MAO-B inhibitory activity was exerted by the methanol extract of the prepared formula (IC₅₀ of 712.19 ± 13.90 ng/mL) compared to selegiline (IC₅₀ of 581.69 ± 11.35 ng/mL). The highest value of the total phenolic content was shown by Angelica sinensis methanolic extract (76.15 ± 0.1 mg/g) followed by Glycyrrhiza glabra methanolic extract (65.74 ± 0.1 mg/g), then the mixture's methanolic extract of the four herbs (37.04 ± 0.1 mg/g).

The neuroprotective attribution of Ocimum basilicum: a review on the prevention and management of neurodegenerative disorders

Background

Bioactive principles from various natural resources including medicinal herbs have always played a crucial role in healthcare settings and increasingly became key players in drug discovery and development for many biopharmaceutical applications. Additionally, natural products (NPs) have immense arrangement of distinctive chemical structures with diverse functional groups that motivated numerous investigators including synthetic chemists to discover new therapeutic entities. Numerous pre-clinical investigations involving the animal models have evident the usefulness of these NPs against various human diseases including neurodegenerative disorders (NDs).

Main text

Ocimum basilicum Linn (O. basilicum L.), also known as sweet basil, is well practiced in traditional healthcare systems and has been used to treat various human illnesses, which include malaria, skin disease, diarrhea, bronchitis, dysentery, arthritis, eye diseases, and insect bites and emphasize the significance of the ethno-botanical approach as a potential source of novel drug leads With the growing interest in advanced techniques, herbal medicine and medicinal plants explorations are still considered to be a novel resource for new pharmacotherapeutic discovery and development. O. basilicum L and its bioactive principles including apigenin, eugenol, myretenal, β-sitosterol, luteolin, rosmarinic acid, carnosic acid, essential oil (EO)-rich phenolic compounds, and others like anthocyanins and flavones could be of therapeutic values in NDs by exhibiting their neuro-protective efficacy on various signaling pathways. The present comprehensive review collected various related information using the following searching engines such as PubMed, Science Direct, Google Scholar, etc. and focused mainly the English written documents. The search period comprised of last two decades until present.

Conclusion

Although these efficacious plant genera of prime importance and has potential medical and socioeconomic importance, yet the pivotal evidence for its neuroprotective potential in novel clinical trials remains lacking. However, with the available wealth of obtainable literature on this medicinal plant, which supports this review and concludes that O. basilicum L may function as a promising therapeutics for the treatment of NDs.

Genus Arisaema: A Review of Traditional Importance, Chemistry and Biological Activities

BACKGROUND

The Arisaema (Araceae) is a genus of approximately 180 perennial herbs widely distributed in the evergreen and deciduous forests. This genus (Arisaema) has been used as a medicinal agent since ancient times. Experimental investigations have shown a promising positive correlation with its folklore claim and this encourages us to report updated medicinal review (genus Arisaema) for future research.

OBJECTIVE

This review aimed to summarize the ethnobotany, folklore uses, chemistry and biological activities.

CONCLUSION

The comprehensive literature on genus Arisaema indicates the presence of terpenoids, flavonoids, and glycosphingolipids as the principal chemical constituents. Additionally, phytosterols, alkaloids, carboline derivatives and miscellaneous compounds were documented in plants of genus Arisaema. Biological investigations led to the credentials of antioxidant, anticancer, insecticidal, antimicrobial, anthelmintic and hepatoprotective activities. Following, several plant species are promising candidates for the treatment of cancer, parasitic diseases and microbial infection complications. Though, a lot of facets of this genus like phytoconstituents identification, mechanistic profile, adverse effects and clinical studies are still quite limited. Thus, this systematic review may act as a powerful tool in future studies for promoting health benefits against various health hazards.

Flavonoids and Polyphenolic Compounds as Potential Talented Agents for the Treatment of Alzheimer's Disease and their Antioxidant Activities

Aging is a normal human cycle and the most important risk factor for neurodegenerative diseases. Alternations in cells due to aging contribute to loss of the nutrient-sensing, cell function, increased oxidative stress, loss of the homeostasis cell, genomic instability, the build-up of malfunctioning proteins, weakened cellular defenses, and a telomere split. Disturbance of these essential cellular processes in neuronal cells can lead to life threats including Alzheimer's disease (AD), Huntington's disease (HD), Lewy's disease, etc. The most common cause of death in the elderly population is AD. Specific therapeutic molecules were created to alleviate AD's social, economic, and health burden. In clinical practice, almost every chemical compound was found to relieve symptoms only in palliative treatment. The reason behind these perfect medicines is that the current medicines are not effective in targeting the cause of this disease. In this paper, we explored the potential role of flavonoid and polyphenolic compounds, which could be the most effective preventative anti-Alzheimer's strategy.

Imbalance between dopamine and serotonin caused by neonatal habenula lesion

Alterations in dopamine (DA) and serotonin (5-HT) transmission have been implicated in the pathophysiology of attention deficit/hyperactivity disorder (ADHD). We have previously reported that juvenile rats with neonatal habenula lesion (NHL) exhibit an assortment of behavioral alterations resembling ADHD symptoms. In this study, we investigated the impacts of NHL on DA and 5-HT transmission in mesocorticolimbic regions of rats. Male Sprague-Dawley rats with microinjection of ibotenic acid into the habenula at postnatal day (PND) 7 were subjected for a battery of locomotion test, object exploration test and delay discounting test in the juvenile period (PND28-35), followed by DA and 5-HT brain tissue concentration measurements using high-performance liquid chromatography (HPLC). NHL rats exhibited hyperlocomotion, impulsivity, and attention deficits. NHL induced alterations of tissue DA and 5-HT concentrations only in some mesocorticolimbic regions. However, positive correlations, indicating the balance, between DA and 5-HT observed in control (CTR) rats, were more extensively disrupted across mesocorticolimbic regions in NHL rats. Pharmacological manipulations that modulated both DA and 5-HT systems simultaneously with Astragalus membranaceus (AM) and its active compound formononetin (FOR) normalized the NHL-induced DA and 5-HT imbalance in several brain areas, which consequently improved the behavioral alterations. These results suggest that behavioral alterations caused by NHL may be associated with mesocorticolimbic DA/5-HT imbalance. Drug treatments targeting multiple monoamine systems may be useful to improve the NHL-induced changes.

Flavonoids Isolated from Vitex grandifolia, an Underutilized Vegetable, Exert Monoamine A & B Inhibitory and Anti-inflammatory Effects and Their Structure-activity Relationship

Objectives

Vitex grandifolia belongs to family Lamiaceae; it consists of flowering plants and it is also called the mint family. The Yoruba people of southwest Nigeria called it "Oriri" or "Efo oriri". This plant is classified as an underutilized vegetable and little is known about its phytochemistry or its biological evaluations.

Materials and Methods

Methanol extracts of the dried leaves and stem of the plant were subjected to fractionation and isolation using vacuum layer and column chromatography methods. The structures of the compounds were elucidated using spectroscopic techniques including IR, 1D-, and 2D-NMR and by comparison with the data reported in the literature. They were evaluated in vitro for the inhibition of monoamine recombinant human MAO-A and -B and anti-inflammatory activities.

Results

Three known flavonoids were isolated from the methanolic extract of the leaves of V. grandifolia for the first time to the best of our knowledge, i.e. isoorientin (1), orientin (2), and isovitexin (3). Most of the isolated compounds showed selective inhibition of monoamine oxidase B, inhibition of MAO-B by isoorientin (1) and orientin (2) were 9-fold more potent (IC₅₀ (μg/mL) of 11.08 and 11.04) compared to the inhibition of MAO-A (IC₅₀ (μg/mL) of ˃100), while clorgyline and deprenyl were used as positive standards. The isolated flavonoids displayed good activity against the NF-ﭏb assay with IC₅₀ (μg/mL) of 8.9, 12, and 18. This study establishes a link between the structure and the biological activities on the basis of the different patterns of substitution, particularly the C2=C3 double bond and the position of glucose moiety.

Conclusion

This study is the first to establish the phytochemistry of the polar part of V. grandifolia and the anti-inflammatory and neuroprotective role of these isolated compounds.

Baihe Zhimu formula attenuates the efficacy of tamoxifen against breast cancer in mice through modulation of CYP450 enzymes

Background

Major depression is an important complication in patients with breast cancer, but is an underrecognized and undertreated condition in this population. The Baihe Zhimu Tang (BZ formula) is a traditional Chinese formula consisting of Lilium brownii var. viridulum Baker (L. brownii) and Anemarrhena asphodeloides (A. asphodeloides) Bunge that is used for the treatment of depression. However, the interaction between tamoxifen and BZ formula is frequently overlooked by traditional and alternative medical doctors. In the present study, the influence of BZ formula on the effectiveness of tamoxifen in breast cancer in mice and the effects of tamoxifen on the antidepressant effect of BZ formula and its major components mangiferin and timosaponin BII in mice were investigated.

Methods

Identification of the major components of BZ formula was performed using fast HPLC-tandem mass spectrometry (HPLC-MS/MS). The main flavonoids and saponins in A. asphodeloides were determined by HPLC-UV and HPLC-ELSD, separately. The antidepressant efficacy of BZ formula was evaluated using a mouse tail-suspension test. The effects of BZ formula on the antineoplastic activity of tamoxifen were performed in a mouse xenograft model of human breast cancer MCF-7 cells. P450 activity was determined using microsomal incubations by HPLC-MS/MS. Measurement of serum concentrations of tamoxifen and its metabolites was used by HPLC-MS/MS.

Results

BZ formula attenuated the effectiveness of tamoxifen treatment of breast cancer and reduced the concentrations of endoxifen and 4-OH-tamoxifen in tumor-bearing mice. Of two of the major components of BZ formula, the antidepressant effect of mangiferin, but not timosaponin BII, was significantly inhibited by tamoxifen in mice. BZ formula and its component mangiferin also significantly inhibited CYP450 enzyme activity in rat liver microsomes.

Conclusion

BZ formula attenuated the effectiveness of tamoxifen in treatment of breast cancer in mice by influencing CYP450 enzymes. The present study laid a foundation for the treatment of patients with breast cancer and depression by BZ formula or other Chinese herbal formulas containing A. asphodeloides.

Potential plant-derived catecholaminergic activity enhancers for neuropharmacological approaches: A review

BACKGROUND

Catecholamines (CAs) have been reported to be involved in numerous functions including central nervous system. CA release from the intra neuronal storage vesicles aid in the therapy of various neurological and neuropsychiatric disorders where the catecholaminergic neurotransmission is compromised. Bioavailability of CA at the synapse can be increased through stimulated neurotransmitter release, monoamine oxidase and CA reuptake inhibition. Plant based galenicals are reported to have similar CA enhancement activities and have been used for the management of neurological disorders.

AIM

To review evidence-based literature with plant extracts, bioactive compounds, and composite extracts that modulate central catecholaminergic system, thereby enhancing CA activity for beneficial neurological effect.

METHODS

Electronic databases such as PubMed, Scopus, and ScienceDirect were used to search scientific contributions until January 2018, using relevant keywords. Literature focusing plant-derived CA enhancing compounds, extracts and/or composite extracts were identified and summarized. In all cases, dose, route of administration, the model system and type of extract were accounted.

RESULTS

A total of 49 plant extracts, 31 compounds and 16 herbal formulations have shown CA activity enhancement. Stimulated CA release from the storage vesicles, monoamine oxidase and CA reuptake inhibition were the major mechanisms involved in the increase of CA bioavailability by these phytoconstituents.

CONCLUSION

This review provides an overview on the phytoconstituents with CA enhancement property that have been used for neuropsychiatric disorders. Such herbal remedies will provide an avenue for cost effective and easily available medication which have holistic approach towards disease management. There is also scope for alternate medicines or prototype drug development utilizing these phytomedicines for treating neurodegenerative diseases. However, hurdles are to be met for analyzing the mode and mechanism of action associated with these phytomedicines and their proper scientific documentation.

Neuroprotective Strategies for Neurological Disorders by Natural Products: An update

Nature has bestowed mankind with surplus resources (natural products) on land and water. Natural products have a significant role in the prevention of disease and boosting of health in humans and animals. These natural products have been experimentally documented to possess various biological properties such as antioxidant, anti-inflammatory and anti-apoptotic activities. In vitro and in vivo studies have further established the usefulness of natural products in various preclinical models of neurodegenerative disorders. Natural products include phytoconstituents, like polyphenolic antioxidants, found in herbs, fruits, nuts, vegetables and also in marine and freshwater flora. These phytoconstituents may potentially suppress neurodegeneration and improve memory as well as cognitive functions of the brain. Also, they are known to play a pivotal role in the prevention and cure of different neurodegenerative diseases, such as Alzheimer's disease, epilepsy, Parkinson's disease and other neuronal disorders. The large-scale neuro-pharmacological activities of natural products have been documented due to the result of either the inhibition of inflammatory processes, or the up-regulation of various cell survival proteins or a combination of both. Due to the scarcity of human studies on neuroprotective effects of natural products, this review focuses on the various established activities of natural products in in vitro and in vivo preclinical models, and their potential neuro-therapeutic applications using the available knowledge in the literature.

GABAA Receptor Density Is Not Altered by a Novel Herbal Anxiolytic Treatment

Anxiety disorders are highly prevalent and considered a major public health concern worldwide. Current anxiolytics are of limited efficacy and associated with various side effects. Our novel herbal treatment (NHT), composed of four constituents, was shown to reduce anxiety-like behavior while precluding a common side effect caused by current anxiolytics, i.e., sexual dysfunction. Nevertheless, NHT's mechanism of action is yet to be determined. There is evidence that some medicinal herbs interact with the GABAergic system. Therefore, we aimed to examine whether NHT's anxiolytic-like effect is exerted by alterations in GABA_A receptor density in the hippocampus, prefrontal cortex, and hypothalamus. The effects of 3-weeks treatment with NHT on anxiety-like behavior and locomotion were assessed using the elevated plus maze (EPM) and the open field test (OFT), respectively. Regional GABA_A receptor levels were analyzed using [³H] RO15-1788 high-affinity binding assays. In stressed mice, NHT reduced anxiety-like behavior similarly to the benzodiazepine, clonazepam, while locomotion remained intact. Lack of changes or minor changes in regional GABA_A receptor density in the brain were induced by NHT or clonazepam. In naive mice, performance in the EPM, locomotion and GABA_A receptor densities were not altered by treatment with NHT or clonazepam. These findings support NHT as an efficacious and safe anxiolytic, although the GABAergic involvement remains to be further elucidated.

Functionalized liposomes and phytosomes loading Annona muricata L. aqueous extract: Potential nanoshuttles for brain-delivery of phenolic compounds

BACKGROUND

Multi-target drugs have gained significant recognition for the treatment of multifactorial diseases such as depression. Under a screening study of multi-potent medicinal plants with claimed antidepressant-like activity, the phenolic-rich Annona muricata aqueous extract (AE) emerged as a moderate monoamine oxidase A (hMAO-A) inhibitor and a strong hydrogen peroxide (H₂O₂) scavenger.

PURPOSE

In order to protect this extract from gastrointestinal biotransformation and to improve its permeability across the blood-brain barrier (BBB), four phospholipid nanoformulations of liposomes and phytosomes functionalized with a peptide ligand promoting BBB crossing were produced.

METHODS

AE and nanoformulations were characterized by HPLC-DAD-ESI-MSⁿ, HPLC-DAD, spectrophotometric, fluorescence and dynamic light scattering methods. Cytotoxicity and permeability studies were carried out using an in vitro transwell model of the BBB, composed of immortalized human microvascular endothelial cells (hCMEC/D3), and in vitro hMAO-A inhibition and H₂O₂ scavenging activities were performed with all samples.

RESULTS

The encapsulation/binding of AE was more efficient with phytosomes, while liposomes were more stable, displaying a slower extract release over time. In general, phytosomes were less toxic than liposomes in hCMEC/D3 cells and, when present, cholesterol improved the permeability across the cell monolayer of all tested nanoformulations. All nanoformulations conserved the antioxidant potential of AE, while phosphatidylcholine interfered with MAO-A inhibition assay.

CONCLUSIONS

Overall, phytosome formulations registered the best performance in terms of binding efficiency, enzyme inhibition and scavenging activity, thus representing a promising multipotent phenolic-rich nanoshuttle for future in vivo depression treatment.

Privileged scaffolds as MAO inhibitors: Retrospect and prospects

This review aims to be a comprehensive, authoritative, critical, and readable review of general interest to the medicinal chemistry community because it focuses on the pharmacological, chemical, structural and computational aspects of diverse chemical categories as monoamine oxidase inhibitors (MAOIs). Monoamine oxidases (MAOs), namely MAO-A and MAO-B represent an enormously valuable class of neuronal enzymes embodying neurobiological origin and functions, serving as potential therapeutic target in neuronal pharmacotherapy, and hence we have coined the term "Neurozymes" which is being introduced for the first time ever. Nowadays, therapeutic attention on MAOIs engrosses two imperative categories; MAO-A inhibitors, in certain mental disorders such as depression and anxiety, and MAO-B inhibitors, in neurodegenerative disorders like Alzheimer's disease (AD) and Parkinson's disease (PD). The use of MAOIs declined due to some potential side effects, food and drug interactions, and introduction of other classes of drugs. However, curiosity in MAOIs is reviving and the recent developments of new generation of highly selective and reversible MAOIs, have renewed the therapeutic prospective of these compounds. The initial section of the review emphasizes on the detailed classification, structural and binding characteristics, therapeutic potential, current status and future challenges of the privileged pharmacophores. However, the chemical prospective of privileged scaffolds such as; aliphatic and aromatic amines, amides, hydrazines, azoles, diazoles, tetrazoles, indoles, azines, diazines, xanthenes, tricyclics, benzopyrones, and more interestingly natural products, along with their conclusive SARs have been discussed in the later segment of review. The last segment of the article encompasses some patents granted in the field of MAOIs, in a simplistic way.

Ziziphi spinosae lily powder suspension in the treatment of depression-like behaviors in rats

Background

Depression is a chronic, recurring and potentially life-threatening illness. Current treatments for depression are characterized by a low success rate and associated with a wide variety of side effects. The aim of the present study was to evaluate the behavioral anti-depressant effect of a novel herbal compounds named ziziphi spinosae lily powder suspension, as well as to investigate its potential mechanisms.

Methods

Except for body weight, depressive-like behaviors were also evaluated using forced swimming test, sucrose consumption test and open field test. In order to investigate the underlying potential mechanisms, serum 5-HT and brain 5-HIAA were measured using ultrahigh-performance liquid chromatography and high-performance liquid chromatography, respectively.

Results

Results showed that the herbal compounds ziziphi spinosae lily suspension could alleviate depressive symptoms in rat model of chronic depression. Biochemical analysis revealed that the herbal compounds elevated serum 5-HT and brain 5-HIAA.

Conclusion

Ziziphi spinosae lily powder suspension could alleviate depressive behaviors in depression model animals. The underlying mechanisms may be related to the increase of serum 5-HT in peripheral blood and 5-HIAA in brain. The study provides important mechanistic insights into the protective effect of the herbal compounds against chronic depressive disorder and suggests that the herbal compounds may be a potential pharmacological agent for treatment of major depressive disorder.

Electronic supplementary material

The online version of this article (doi:10.1186/s12906-017-1749-5) contains supplementary material, which is available to authorized users.

Evaluation of the inhibitory effects of eckol and dieckol isolated from edible brown alga Eisenia bicyclis on human monoamine oxidases A and B

Eckol and dieckol are important phlorotannins found in edible brown algae including Eisenia bicyclis, Ecklonia stolonifera, and others. Inhibition of monoamine oxidase (MAO) play an important role in the early management of Parkinson's disease (PD). The aim of this study was to determine the effectiveness of eckol and dieckol isolated from the methanolic extract of E. bicyclis against PD by the inhibition of human MAO-A and MAO-B (hMAO-A and hMAO-B). A sensitive enzyme-based chemiluminescent assay and kinetics methods were used to investigate enzyme inhibition and mode of inhibition. A molecular docking simulation was performed to clarify the binding characteristics of eckol and dieckol to hMAO-A and hMAO-B. The results suggested that methanolic extract of E. bicyclis and its isolated phlorotannins, eckol and dieckol, have potent inhibitory activity against hMAO-A and hMAO-B. The enzyme-based kinetics results demonstrated eckol mixed and non-competitive inhibition of hMAO-A and hMAO-B, respectively, while dieckol non-competitively inhibited both hMAOs. Molecular docking simulation predicted that eckol and dieckol exhibit higher binding affinity towards hMAO-A and hMAO-B through hydrogen bonding and hydrophobic interactions. These findings implicate eckol and dieckol as inhibitors of hMAOs that might be of potential value in the management of PD.

Selective monoamine oxidase B inhibition by an Aphanizomenon flos-aquae extract and by its constitutive active principles phycocyanin and mycosporine-like amino acids

Aphanizomenon flos-aquae (AFA) is a fresh water unicellular blue-green alga that has been traditionally used for over 25 years for its health-enhancing properties. Recent studies have shown the ability of a proprietary AFA extract (Klamin(®)) to improve mood, counteract anxiety, and enhance attention and learning. Aim of this study was to test the monoamine oxidase (MAO) inhibition activity of the same AFA extract and of its constituents phycocyanin (AFA-PC) and mycosporine-like aminoacids (AFA-MAAs). All compounds showed a dose-dependent selective inhibition of MAO-B activity as compared to MAO-A. The IC50 values of the AFA extract (concentration 10 mg/ml), AFA-PC and AFA-MAAs were 6.4 μl/ml, 1.33 μM and 1.98 μM, respectively, evidencing a mixed-type of inhibition for the AFA extract (Ki 0.99 μl/ml), a non-competitive inhibition for AFA-PC (Ki 1.06 μM) and a competitive inhibition for AFA-MAAs (Ki 0.585 μM). These results are important to explain the neuromodulating properties of the AFA extract Klamin(®), which is rich in phenylethylamine, a general neuromodulator, that would nevertheless rapidly destroyed by MAO-B enzymes without the inhibitory activity of the synergic active principles AFA-PC and AFA-MAAs. The present investigation thus proposes the extract as potentially relevant in clinical areas such as mood disorders and neurodegenerative diseases.

An Evidence-Based Systematic Review of Goji (Lycium spp.) by the Natural Standard Research Collaboration

An evidence-based systematic review of goji (Lycium spp.) by the Natural Standard Research Collaboration consolidates the safety and efficacy data available in the scientific literature using a validated, reproducible grading rationale. This article includes written and statistical analysis of clinical trials, plus a compilation of expert opinion, folkloric precedent, history, pharmacology, kinetics/dynamics, interactions, adverse effects, toxicology, and dosing.

In vitro evaluation of Bacopa monniera extract and individual constituents on human recombinant monoamine oxidase enzymes

Bacopa monniera is a traditional Ayurvedic medicinal plant that has been used worldwide for its nootropic action. Chemically standardized extract of B. monniera is now available as over the counter herbal remedy to enhance memory in children and adults. Considering the nootropic action of B. monniera, we evaluated the effect of clinically available B. monniera extract and six of B. monniera constituents (bacoside A3, bacopaside I, bacopaside II, bacosaponin C, bacosine, and bacoside A mixture) on recombinant human monoamine oxidase (MAO) enzymes. The effect of B. monniera extract and individual constituents on human recombinant MAO-A and MAO-B enzymes was evaluated using MAO-Glo(TM) assay kit (Promega Corporation, USA), following the instruction manual. IC50 and mode of inhibition were measured for MAO enzymes. Bacopaside I and bacoside A mixture inhibited the MAO-A and MAO-B enzymes. Bacopaside I exhibited mixed mode of inhibition with IC50 and Ki values of 17.08 ± 1.64 and 42.5 ± 3.53 µg/mL, respectively, for MAO-A enzyme. Bacopaside I is the major constituent of B. monniera, which inhibited the MAO-A enzyme selectively.

Selective MAO-B inhibitors: a lesson from natural products

Monoamine oxidases (MAOs) are mitochondrial bound enzymes, which catalyze the oxidative deamination of monoamine neurotransmitters. Inside the brain, MAOs are present in two isoforms: MAO-A and MAO-B. The activity of MAO-B is generally higher in patients affected by neurodegenerative diseases like Alzheimer's and Parkinson's. Therefore, the search for potent and selective MAO-B inhibitors is still a challenge for medicinal chemists. Nature has always been a source of inspiration for the discovery of new lead compounds. Moreover, natural medicine is a major component in all traditional medicine systems. In this review, we present the latest discoveries in the search for selective MAO-B inhibitors from natural sources. For clarity, compounds have been classified on the basis of structural analogy or source: flavonoids, xanthones, tannins, proanthocyanidins, iridoid glucosides, curcumin, alkaloids, cannabinoids, and natural sources extracts. MAO inhibition values reported in the text are not always consistent due to the high variability of MAO sources (bovine, pig, rat brain or liver, and human) and to the heterogeneity of the experimental protocols used.

Screening of plants used in Danish folk medicine to treat depression and anxiety for affinity to the serotonin transporter and inhibition of MAO-A

ETHNOPHARMACOLOGICAL RELEVANCE

A number of plant species are used in Danish folk medicine for treatment of depression and anxiety.

MATERIALS AND METHODS

Aqueous and ethanolic extracts of 17 plant species were tested for affinity to the serotonin transporter and for inhibition of MAO-A-both targets for antidepressive treatment.

RESULTS

An ethanolic extract of aerial parts of Borago officinalis had affinity to the serotonin transporter. Ten extracts, from eight plants, had IC(50) values below 25μg/ml extract in the MAO-A assay. The most active extracts in the MAO-A assay were the ethanol extract of seeds of Trigonella foenum-graecum (IC(50) 4μg/ml); ethanol extract of leaves of Apium graveolens (IC(50) 5μg/ml) and the water extract of aerial parts of Calluna vulgaris (IC(50) 8μg/ml).

CONCLUSIONS

Besides Borago officinalis, which toxicity profile excludes it from further development as an herbal drug, none of the plants had potential as serotonin reuptake inhibitors. Several plants had MAO-A inhibitory activity.

The pharmacological effects ofSalvia species on the central nervous system

Salvia is an important genus consisting of about 900 species in the family Lamiaceae. Some species of Salvia have been cultivated world wide for use in folk medicine and for culinary purposes. The dried root of Salvia miltiorrhiza, for example, has been used extensively for the treatment of coronary and cerebrovascular disease, sleep disorders, hepatitis, hepatocirrhosis, chronic renal failure, dysmenorrhea, amenorrhea, carbuncles and ulcers. S. officinalis, S. leriifolia, S. haematodes, S. triloba and S. divinorum are other species with important pharmacological effects. In this review, the pharmacological effects of Salvia species on the central nervous system will be reviewed. These include sedative and hypnotic, hallucinogenic, skeletal muscle relaxant, analgesic, memory enhancing, anticonvulsant, neuroprotective and antiparkinsonian activity, as well as the inhibition of ethanol and morphine withdrawal syndrome.

NATURAL HEALTH PRODUCTS AND DRUG DISPOSITION

Botanicals such as herbal products (HPs) and nutraceuticals (NCs) are often regarded as low risk because of their long history of human use. Anecdotal and literature reports of adverse drug events (ADEs) and clinical studies with HPs are increasing, but many of the reports are incomplete and contradictory. These reports need to identify confounding factors and explain contradictory findings if they are to help health care professionals or patients understand what risks are involved. HPs are complex botanicals, not single-active ingredient (SAI) products. Studies can be confounded by different manufacturing processes and formulations, including cosmetics and food supplements; environment; chemotypes; misidentification or adulteration; and factors associated with the patient or user population such as use, total drug load, and genetics. Future studies need to be conducted with characterized product that includes all commercially available related products. Clinical trials should be relevant to the user population and take into account the confounding factors that may influence the interpretation of the findings.

Monoamine oxidase B (MAO-B) inhibition by active principles from Uncaria rhynchophylla

Attenuation of monoamine oxidase B (MAO-B) activity may provide protection against oxidative neurodegeneration. For this reason, inhibition of MAO-B activity is used as part of the treatment of Parkinson's and Alzheimer's patients. The hook of Uncaria rhynchophylla (Miq.) Jacks. (Rubiaceae) is a traditional Chinese herbal drug that is generally used to treat convulsive disorders. In this study, the fractionation and purification of Uncaria rhynchophylla extracts using a bioguided assay isolated two known compounds, (+)-catechin and (-)-epicatechin. The compounds inhibited MAO-B, as measured by an assay of rat brain MAO-B separated by electrophoresis on a 7.5% native polyacrylamide gel. The IC(50) values of (+)-catechin and (-)-epicatechin were 88.6 and 58.9 microM, respectively, and inhibition occurred in a dose-dependent manner, as measured by the fluorescence method. The Lineweaver-Burk plot revealed K(i) values for (+)-catechin and (-)-epicatechin of 74 and 21 microM, respectively. This suggests that these two compounds, isolated here for the first time from Uncaria rhynchophylla, might be able to protect against neurodegeneration in vitro, and, therefore, the molecular mechanism deserves further study. This finding may also increase interest in the health benefits of Uncaria rhynchophylla.