Chemical composition, potential toxicity, and quality control procedures of the crude drug of Cyrtopodium macrobulbon

Medicinal Orchids of Mexico: A Review

Some species of the Orchidaceae family are used in Mexican traditional medicine. However, there are no current and critical compilations of the medicinal uses and pharmacological effects of the members of the Orchidaceae family. This review provides a current, critical, and comprehensive analysis of the traditional medicinal uses, pharmacological reports, and active compounds isolated from Mexican orchids. A total of 62 Mexican orchids with medicinal potential have been recorded, of which 14 have scientific evidence. The remaining 48 plant species have ethnomedicinal information but have not been validated with scientific studies. These orchids are distributed in 14 states of the Mexican Republic, mainly in the southern region of Mexico. The most common pharmacological activities reported are anti-inflammatory, vasorelaxant, antinociceptive, antioxidant, spasmolytic, antihypertensive, and hallucinogenic activities. It is necessary to increase the number of pharmacological, phytochemical, and toxicological studies with medicinal orchids from Mexico because there are scientific studies on only 22.5% of these species. In further studies, it will be possible to evaluate the pharmacological effects of Mexican orchids in clinical trials. In addition, the mechanisms of action by which plant extracts and their active compounds exert medicinal effects remain to be studied. Plant extracts from orchids and their active compounds show promising antinociceptive and spasmolytic effects, respectively.

Ethnomedicinal Study and Evaluation of the Anxiolytic-like and Diuretic Effects of the Orchid Stanhopea tigrina Bateman ex Lindl-(Orchidaceae)

Stanhopea tigrina Bateman ex Lindl. (Orchidaceae) is an orchid endemic to Mexico, known as "Calavera" or "calaverita", in the Huasteca Potosina (central region of Mexico). This plant species is used for the folk treatment of mental disorders and urological kidney disorders, according to the ethnomedicinal information obtained in this study. Ethanolic extracts of leaves (HE) and pseudobulb (PE) were obtained by microwave-assisted extraction (MAE). Gas Chromatography coupled with Mass Spectrometry (GC-MS) was used to carry out the chemical characterization of HE and PE. The pharmacological effects (antioxidant, diuretic, anxiolytic, locomotor, hypnotic, and sedative) of HE and PE were evaluated. The possible mechanism of action of the anxiolytic-like activity induced by HE was assessed using inhibitors of the GABAergic, adrenergic, and serotonergic systems. The possible mechanism of the diuretic action of HE was assessed using prostaglandin inhibitory antagonists and nitric oxide synthase (NOS) blockers. HE at 50 and 100 mg/kg exerted anxiolytic-like activity without inducing hypnosis or sedation. Flumazenil, prazosin, and ketanserin inhibited the anxiolytic-like activity shown by HE, which suggests the participation of GABA, α1-adrenergic receptors, and 5-HT2 receptors, respectively. The diuretic effect was reversed by the non-selective NOS inhibitor L-NAME, which caused the reduction in nitric oxide (NO). These results demonstrate that the ethanolic extract of S. tigrina leaves exhibited anxiolytic-like activity and diuretic effects without inducing hypnosis or sedation. This work validates the medicinal uses of this orchid species.

Palladium-Catalyzed Sequential Cross-Coupling/Annulation of ortho-Vinyl Bromobenzene with Aryl Bromide: Bimetallic Pathway versus Pd(II)-Pd(IV) Pathway: A DFT Investigation

The palladium-catalyzed sequential cross-coupling/annulation of ortho-vinyl bromobenzenes with aryl bromides generating phenanthrenes was characterized by density functional theory (DFT). The Pd(II)-Pd(IV) pathway (Path V) is shown to be less probable than the bimetallic pathway (Path I), the latter proceeding via the following six steps: oxidative addition, vinyl-C(sp2)-H activation, Pd(II)-Pd(II) transmetalation, C-C coupling, aryl-C(sp2)-H activation, and reductive elimination. The aryl-C(sp2)-H activation process acts as the rate-determining step (RDS) of the entire chemical transformation, with an activation free energy barrier of ca. 27.4-28.8 kcal·mol-1, in good agreement with the corresponding experimental data (phenanthrenes' yields of ca. 65-90% at 130 °C after 5 h of reaction). The K2CO3 additive effectively reduces the activation free energy barrier of the RDS through direct participation in the reaction while preferentially modulating the charge distributions and increasing the stability of corresponding intermediates and complexes along the reaction path. Furthermore, bonding and electronic structure analyses of the key structures indicate that the chemo- and regioselectivities of the reaction are strongly influenced by both electronic effects and steric hindrance.

Discovery of inhibitors of protein tyrosine phosphatase 1B contained in a natural products library from Mexican medicinal plants and fungi using a combination of enzymatic and in silico methods*

This work aimed to discover protein tyrosine phosphatase 1B (PTP1B) inhibitors from a small molecule library of natural products (NPs) derived from selected Mexican medicinal plants and fungi to find new hits for developing antidiabetic drugs. The products showing similar IC50 values to ursolic acid (UA) (positive control, IC50 = 26.5) were considered hits. These compounds were canophyllol (1), 5-O-(β-D-glucopyranosyl)-7-methoxy-3',4'-dihydroxy-4-phenylcoumarin (2), 3,4-dimethoxy-2,5-phenanthrenediol (3), masticadienonic acid (4), 4',5,6-trihydroxy-3',7-dimethoxyflavone (5), E/Z vermelhotin (6), tajixanthone hydrate (7), quercetin-3-O-(6″-benzoyl)-β-D-galactoside (8), lichexanthone (9), melianodiol (10), and confusarin (11). According to the double-reciprocal plots, 1 was a non-competitive inhibitor, 3 a mixed-type, and 6 competitive. The chemical space analysis of the hits (IC50 < 100 μM) and compounds possessing activity (IC50 in the range of 100-1,000 μM) with the BIOFACQUIM library indicated that the active molecules are chemically diverse, covering most of the known Mexican NPs' chemical space. Finally, a structure-activity similarity (SAS) map was built using the Tanimoto similarity index and PTP1B absolute inhibitory activity, which allows the identification of seven scaffold hops, namely, compounds 3, 5, 6, 7, 8, 9, and 11. Canophyllol (1), on the other hand, is a true analog of UA since it is an SAR continuous zone of the SAS map.

Bioactive natural products from orchids native to the Americas - A review

The purpose of this review is to provide information on the traditional uses, phytochemical and pharmacological studies performed with species of orchids native to the Americas and the Caribbean Islands. The treatment of inflammation is the most traditional use for plants of this family, specially in Central America, while anti-inflammatory and anticancer assays are oftenly reported in pharmacological investigations. From the chemical point of view, they are sources of phenanthrenoids and stilbenes, rare secondary metabolites not commonly found in other families of plants, as well as cycloartane triterpenes, pyrrolizidine alkaloids and flavonoids. Since just few species were chemically and pharmacologically studied, in comparison to the large number of native species (less than 0.5% of the total), the orchids of the New World may be an interesting niche for the discovery of new, bioactive natural products.

Fused diethynylbenzenes and phenanthrenes via arynes with alkynylsilanes

A method for the hydroalkynylation and catalytic cyclization reactions of hexadehydro-Diels-Alder-derived benzynes is described. Diethynylbenzene derivatives are generated in a one-step reaction via trimethylsilyl-alkyne groups with benzyne formed by heating the appropriate tetrayne substrate. Trimethyl(phenylethynyl)silane loses TMS and binds to the electron-deficient site on HDDA-derived benzynes, and then phenanthrene was synthesized under mild reaction conditions by transition-metal-free, base promoted intramolecular cyclization.

Antinociceptive effects of Laelia anceps Lindl. and Cyrtopodium macrobulbon (Lex.) G.A. Romero & Carnevali, and comparative evaluation of their metabolomic profiles

ETHNOPHARMACOLOGICAL RELEVANCE

Laelia anceps and Cyrtopodium macrobulbon are two orchids used in Mexican traditional medicine for treating pain.

AIM OF THE STUDY

The individual antinociceptive activity of ethanol extracts from the roots of Laelia anceps (LAE) and Cyrtopodium macrobulbon (CME) was evaluated, and their metabolomic profiles were comparatively evaluated. The antinociceptive activity of CME and naproxen combination (1:1) was also addressed.

MATERIALS AND METHODS

The antinociceptive actions of LAE and CME were examined using three nociceptive tests. The combination of CME with naproxen was evaluated in the acetic acid test using isobologram analysis. Metabolomic analysis was performed using capillary reversed phase liquid chromatography-electrospray ionization-high resolution mass spectrometry and the MS-DIAL 4.70 software was used for data analysis and statistics.

RESULTS

LAE (ED₅₀ = 48.4 mg/kg) and CME (ED₅₀ = 17.8 mg/kg) showed antinociceptive activity in the acetic acid test. Pre-treatment with L-NAME reverted the antinociceptive effects of LAE and CME in the acetic acid test. LAE (ED₅₀ = 97 mg/kg) and CME (ED₅₀ = 29 mg/kg) also induced antinociceptive activity in the second phase of the formalin test. The combination of CME with naproxen induced synergistic (interaction index = 0.434) antinociceptive effects (ED₅₀ = 10.6 mg/kg). Overall, 156 compounds allocated in 97 different ontologies were found to be differentially expressed in the two orchids; among them, 125 compounds corresponded to LAE and 31 to CME. Three phenanthrene derivatives annotated in CME might be associated with its antinociceptive activity.

CONCLUSION

LAE and CME induced antinociceptive activity with the possible participation of the nitric oxide pathway. CME in combination with naproxen synergistically produces antinociceptive effects in the acetic acid test. The untargeted metabolomic analysis allowed for annotation of several compounds potentially involved in the therapeutic potential of two plants; among them, three phenanthrene derivatives might contribute to the observed antinociceptive activity.

Palladium-Catalyzed Rearrangement Reaction to Access 1-Phenanthrol Derivatives

This manuscript describes an unusual Pd-catalyzed rearrangement reaction. It provides efficient access to 1-phenanthrol derivatives using allyloxy-tethered aryl iodides. This rearrangement process involves the cleavage of C-I bond, C-O bond...

Mexican Plants and Derivates Compounds as Alternative for Inflammatory and Neuropathic Pain Treatment-A Review

Despite the availability of many anti-pain drugs, in the form of NSAIDs, steroids, gabapentinoids, opioids, and antidepressants, in this study we address the natural compounds belonging to the group of Mexican medicinal plants or "Mexican folk medicine", used for pain management in Mexico. Our interest in this subject is due to the growing idea that "natural is harmless" and to the large number of side effects exhibited in pharmacotherapy. The objective of this review was to document the scientific evidence about Mexican medicinal plants and their derivatives used for inflammatory and neuropathic pain treatment, as well as the mechanisms of action implicated in their antinociceptive effects, their possible adverse effects, and the main pharmacological aspects of each plant or compound. Our data review suggested that most studies on Mexican medicinal plants have used inflammatory experimental models for testing. The anti-pain properties exerted by medicinal plants lack adverse effects, and their toxicological assays report that they are safe to consume; therefore, more studies should be performed on preclinical neuropathic pain models. Moreover, there is no convincing evidence about the possible mechanisms of action involved in the anti-pain properties exerted by Mexican plants. Therefore, the isolation and pharmacological characterization of these plant derivatives' compounds will be important in the design of future preclinical studies.

Phenanthrenes/dihydrophenanthrenes: the selectivity controlled by different benzynes and allenes

A method for the intermolecular annulation of benzynes with allenes is disclosed. This protocol utilized allenes as an unconventional diene component for the selective synthesis of phenanthrenes and dihydrophenanthrenes under the control of different benzyne precursors, featuring high atom-economy and good functional group compatibility. Density functional theory (DFT) calculations reveal that different migratory routes of the aromatic C-H bond are crucial for the observed selectivity.

Metabolomic analysis of Cyrtopodium glutiniferum extract by UHPLC-MS/MS and in vitro antiproliferative and genotoxicity assessment

ETHNOPHARMACOLOGICAL RELEVANCE

Extracts of orchids have been traditionally used as human phytotherapeutics. Cyrtopodium flavum, for example, due to the analgesic and anti-inflammatory properties, beside the capacity of heal skin lesions has been focus of research. Also Cyrtopodium glutiniferum, an orchid found in the Brazilian southeastern rainforest, is known to synthesize anti-inflammatory glucomannans in the pseudobulbs, as other potentially therapeutic compounds.

AIM OF THE STUDY

We have reported the first metabolomic analysis focused on the phenols expression of the neotropical orchid Cyrtopodium glutiniferum Raddi, besides free radical scavenging, anti-inflammatory and antiproliferative activities, and the genotoxicity properties of the aqueous extract.

MATERIAL AND METHODS

The metabolomics of C. glutiniferum aqueous extract was performed through UHPLC-MSⁿ acquisition. We have detected the scavenging potential of the extract using DPPH assay. The genotoxic potential was performed by Ames Test (0-5000 μg mL^-1) and micronucleous assay (0-5000 μg mL^-1) in RAW264.7 cells. The cytotoxic potential of the extract against RAW264.7 was tested by WST-1 assay (0-500 μg mL^-1). And after all, the RAW264.7 cells were treated with non-cytotoxic concentrations of C. glutiniferum (0-50 μg mL^-1) to evaluate the antiproliferative and anti-inflammatory potential, besides the mitochondrial activity.

RESULTS

From the 55 molecules identified, 45.5% belonged to the phenolic compounds database from Phenol Explorer, 29% to an in-house Orchidaceae molecules database, and 25.5% to both. Among the identified phenolic compounds, 18 subclasses were discriminated, being phenanthrenes the most abundant. Doses-dependent of C. glutiniferum extracts were able to induce DPPH free radicals scavenging and also to increase TA100 His⁺ revertants, in metabolic environment, showing mutagenicity just in the highest concentration, of 5 mg/plate. On Eukaryotic cell models, the extract also has induced dose-response and time-response cytotoxicity against RAW264.7 macrophages, mainly after 48 h and 72 h, even though the extract has not been able to induce the increase of micronucleated cells and mitotic index alteration on Micronucleus assay. The activation and proliferation of macrophages cultures were downregulated after 24 h and 48 h by the non-cytotoxic concentrations of the extract in a dose-dependent manner.

CONCLUSIONS

The Cyrtopodium glutiniferum metabolomics, anti-inflammatory and anti-proliferative properties observed in this study suggest a therapeutic efficacy of the orchid extract applied in folk medicine.

In situ analysis of oxytetracycline tablets based on matrix-assisted laser desorption/ionization mass spectrometry imaging

RATIONALE

A thorough understanding of the content and distribution of active ingredients in pharmaceuticals is essential for drug efficacy and safety. Technological advancements in mass spectrometry imaging present an opportunity for methodological innovation by providing qualification and quantification analysis, as well as spatial information, in the same assay, which has great potential for applications in the rapid analysis and quality control of drugs.

METHODS

Matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) was employed to directly analyze oxytetracycline tablets in order to map the distribution of the active constituent within the whole tablet. Quantitative analysis was capable of differentiating tablets containing various doses of the active pharmaceutical ingredient.

RESULTS

To establish the methodology, detailed factors that influence matrix spraying and spatial resolution during sample preparation and the data acquisition process were optimized systematically. Quantitative analysis could differentiate the tablets containing various doses of the active compound. The proposed method was successfully applied to analyze real commercial tablets.

CONCLUSIONS

The developed method could successfully achieve the spatial location of oxytetracycline in actual tablet samples. These results could contribute to pharmaceutical tracing technology, especially the formulation process of tablets, which is helpful for monitoring the quality of pharmaceutical products and guaranteeing drug security.

Applications of machine learning in GPCR bioactive ligand discovery

GPCRs constitute the largest druggable family having targets for 475 Food and Drug Administration (FDA) approved drugs. As GPCRs are of great interest to pharmaceutical industry, enormous efforts are being expended to find relevant and potent GPCR ligands as lead compounds. There are tens of millions of compounds present in different chemical databases. In order to scan this immense chemical space, computational methods, especially machine learning (ML) methods, are essential components of GPCR drug discovery pipelines. ML approaches have applications in both ligand-based and structure-based virtual screening. We present here a cheminformatics overview of ML applications to different stages of GPCR drug discovery. Focusing on olfactory receptors, which are the largest family of GPCRs, a case study for predicting agonists for an ectopic olfactory receptor, OR1G1, compares four classical ML methods.

Chemistry and Biology of Selected Mexican Medicinal Plants

Herbal medicines are an integral element of alternative medical care in Mexico, and the best testimony to their efficacy and cultural value is their persistence in contemporary Mexican marketplaces where the highest percentages of medicinal and aromatic plants are sold. This chapter summarizes current trends in research on medicinal plants in Mexico, with emphasis on work carried out at the authors' laboratories. The most relevant phytochemical and pharmacological profiles of a selected group of plants used widely for treating major national health problems are described.From this contribution, it is evident that in the last five decades a significant amount of research on medicinal plants has been performed by Mexican scientists. Such efforts have led to the publication of many research papers in noted peer-reviewed journals and technical books. The isolation and structural characterization of hundreds of bioactive secondary metabolites have been accomplished, and most importantly, these studies have tended to support the ethnomedical uses of many different species. A multidisciplinary approach for investigating these plants has led to an increased emphasis on areas such as phytopharmacology, phytotoxicology, quality control, regulation, and conservation issues for these valuable resources. The medicinal plants analyzed so far have shown a very broad chemical diversity of their constituents, which have a high potential for exhibiting novel mechanistic effects biologically. The chapter shows also that there is need to conduct additional clinical studies on herbal drugs, in particular because the longstanding traditional evidence for their safety is not always sufficient to assure their rational use. There is also need to move to "omics" approaches for investigating the holistic effect and the influence of groups of phytochemicals on the whole organism. Mexican scientists may be expected to have bright prospects in this regard, which will imbue medicinal plant research with a new dynamism in the future.

Oxidative cyclization of 2-allenyl-1,1'-biphenyls with α-carbonyl alkyl bromides: facile access to functionalized phenanthrenes

A new copper-facilitated oxidative cyclization of 2-allenyl-1,1'-biphenyls with α-carbonyl alkyl bromides for producing functionalized phenanthrenes is presented, which represents the first allene 2,3-dicarbofunctionalization triggered by oxidative radical-medicated C3-addition of the terminal allene moiety and C-Br/C-H functionalization.

Metal-free naphthannulation reactions of yne-allenone esters for accessing polycyclic aromatic hydrocarbons

The first metal-free base-promoted naphthannulation reactions of yne-allenone esters were developed for the direct assembly of a wide range of polycyclic aromatic hydrocarbons with generally good yields.

Chemical Constituents from the Aerial Parts of Cyrtopodium paniculatum

We report the first phytochemical study of the neotropical orchid Cyrtopodium paniculatum. Eight new compounds, including one phenanthrene 1, one 9,10-dihydro-phenanthrene 2, one hydroxybenzylphenanthrene 3, two biphenanthrenes 4–5, and three 9,10 dihydrophenanthrofurans 6–8, together with 28 known phenolic compounds, mostly stilbenoids, were isolated from the CH₂Cl₂ extract of its leaves and pseudobulbs. The structures of the new compounds were established on the basis of extensive spectroscopic methods.

Genomics and Evolution in Traditional Medicinal Plants: Road to a Healthier Life

Medicinal plants have long been utilized in traditional medicine and ethnomedicine worldwide. This review presents a glimpse of the current status of and future trends in medicinal plant genomics, evolution, and phylogeny. These dynamic fields are at the intersection of phytochemistry and plant biology and are concerned with the evolution mechanisms and systematics of medicinal plant genomes, origin and evolution of the plant genotype and metabolic phenotype, interaction between medicinal plant genomes and their environment, the correlation between genomic diversity and metabolite diversity, and so on. Use of the emerging high-end genomic technologies can be expanded from crop plants to traditional medicinal plants, in order to expedite medicinal plant breeding and transform them into living factories of medicinal compounds. The utility of molecular phylogeny and phylogenomics in predicting chemodiversity and bioprospecting is also highlighted within the context of natural-product-based drug discovery and development. Representative case studies of medicinal plant genome, phylogeny, and evolution are summarized to exemplify the expansion of knowledge pedigree and the paradigm shift to the omics-based approaches, which update our awareness about plant genome evolution and enable the molecular breeding of medicinal plants and the sustainable utilization of plant pharmaceutical resources.