Pyranocoumarins from tropical species of the genus Calophyllum: a chemotaxonomic study of extracts in the National Cancer Institute collection

Multicomponent Synthesis Strategies, Catalytic Activities, and Potential Therapeutic Applications of Pyranocoumarins: A Comprehensive Review

Fused coumarins, because of their remarkable biological and therapeutic properties, particularly pyranocoumarins, have caught the interest of synthetic organic chemists, leading to the development of more efficient and environmentally friendly protocols for synthesizing pyranocoumarin derivatives. These compounds are the most promising heterocycles discovered in both natural and synthetic sources, with anti-inflammatory, anti-HIV, antitubercular, antihyperglycemic, and antibacterial properties. This review employed the leading scientific databases Scopus, Web of Science, Google Scholar, and PubMed up to the end of 2022, as well as the combining terms pyranocoumarins, synthesis, isolation, structural elucidation, and biological activity. Among the catalysts employed, acidic magnetic nanocatalysts, transition metal catalysts, and carbon-based catalysts have all demonstrated improved reaction yields and facilitated reactions under milder conditions. Herein, the present review discusses the various multicomponent synthetic strategies for pyranocoumarins catalyzed by transition metal-based catalysts, transition metal-based nanocatalysts, transition metal-free catalysts, carbon-based nanocatalysts, and their potential pharmacological activities.

Synthesis and Biological Properties of Pyranocoumarin Derivatives as Potent Anti-Inflammatory Agents

This study aimed to synthesize 23 coumarin derivatives and analyze their anti-inflammatory effects on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 macrophages. A cytotoxicity test performed on LPS-induced RAW264.7 macrophages revealed that none of the 23 coumarin derivatives were cytotoxic. Among the 23 coumarin derivatives, coumarin derivative 2 showed the highest anti-inflammatory activity by significantly reducing nitric oxide production in a concentration-dependent manner. Coumarin derivative 2 inhibited the production of proinflammatory cytokines, including tumor necrosis factor alpha and interleukin-6, and decreased the expression level of each mRNA. In addition, it inhibited the phosphorylation of extracellular signal-regulated kinase, p38, c-Jun NH2-terminal kinase, nuclear factor kappa-B p65 (NF-κB p65), and inducible nitric oxide synthase. These results indicated that coumarin derivative 2 inhibited LPS-induced mitogen-activated protein kinase and NF-κB p65 signal transduction pathways in RAW264.7 cells, as well as proinflammatory cytokines and enzymes related to inflammatory responses, to exert anti-inflammatory effects. Coumarin derivative 2 showed potential for further development as an anti-inflammatory drug for the treatment of acute and chronic inflammatory diseases.

Cytotoxic Metabolites from Calophyllum tacamahaca Willd.: Isolation and Detection through Feature-Based Molecular Networking

Isocaloteysmannic acid (1), a new chromanone, was isolated from the leaf extract of the medicinal species Calophyllum tacamahaca Willd. along with 13 known metabolites belonging to the families of biflavonoids (2), xanthones (3-5, 10), coumarins (6-8) and triterpenes (9, 11-14). The structure of the new compound was characterized based on nuclear magnetic resonance (NMR), high-resolution electrospray mass spectrometry (HRESIMS), ultraviolet (UV) and infrared (IR) data. Its absolute configuration was assigned through electronic circular dichroism (ECD) measurements. Compound (1) showed a moderate cytotoxicity against HepG2 and HT29 cell lines, with IC₅₀ values of 19.65 and 25.68 µg/mL, respectively, according to the Red Dye method. Compounds 7, 8 and 10-13 exhibited a potent cytotoxic activity, with IC₅₀ values ranging from 2.44 to 15.38 µg/mL, against one or both cell lines. A feature-based molecular networking (FBMN) approach led to the detection of a large amount of xanthones in the leaves extract, and particularly analogues of the cytotoxic isolated xanthone pyranojacareubin (10).

Screening of anti-HIV activities in ethanol extract and fractions from Ficus fistulosa leaves

OBJECTIVES

Human immunodeficiency virus (HIV) infection is considered as a major immunosuppressive disease linked to malignancies and other opportunistic infections. Recently, the high prevalence of HIV drug-resistant strains required a high demand for novel antiviral drug development, especially in herbal medicine approaches. The objective of this study was to evaluate the possibility of Ficus fistulosa leaves can inhibit HIV replication in ethanol extract form as well as its fractions using chloroform, ethyl acetate, and butanol solvents.

METHODS

F. fistulosa leaves were extracted using ethanol as a solvent and further gradually fractionated in chloroform, ethyl acetate, and butanol solvents. The targeted persistently infected virus (MT4/HIV) cell lines were cocultured with ethanol extract and fractions at different time points. The syncytium formation and cytotoxicity assays were performed to evaluate the potential antiviral activity of F. fistulosa leaves.

RESULTS

One of the four tested extract/fractions showed antiviral activity against HIV. The ethanol extract showed weak inhibition with a high level of toxicity (IC₅₀ = 8.96 μg/mL, CC₅₀ ≥50 μg/mL, and SI = 5.58). Meanwhile, chloroform fraction effectively inhibited the MT4/HIV cell proliferation while keeping the toxicity to a minimal level (IC₅₀ = 3.27 μg/mL, CC₅₀ = 29.30 μg/mL, and SI = 8.96). In contrast of ethyl acetate fraction and butanol fraction showed no anti HIV activity with a high level of toxicity (CC₅₀ ≥50 μg/mL) and low SI value (>2.17 μg/mL and >0.97 μg/mL).

CONCLUSIONS

Chloroform fraction of F. fistulosa leaves showed effectively as anti-viral activity against MT4/HIV cells.

Targeting Solid Tumors With BTK Inhibitors

The repurposing of FDA-approved Bruton's tyrosine kinase (BTK) inhibitors as therapeutic agents for solid tumors may offer renewed hope for chemotherapy-resistant cancer patients. Here we review the emerging evidence regarding the clinical potential of BTK inhibitors in solid tumor therapy. The use of BTK inhibitors may through lead optimization and translational research lead to the development of new and effective combination regimens for metastatic and/or therapy-refractory solid tumor patients.

4-Chloro-3-formylcoumarin as a multifaceted building block for the development of various bio-active substituted and fused coumarin heterocycles: a brief review

This review presents the diverse synthesis of 3,4-substituted coumarins and 5-, 6- and 7-membered ring fused coumarins using 4-chloro-3-formylcoumarin as the precursor via classical reactions including metal-catalyzed and green reaction protocols.

Naturally Occurring Calanolides: Occurrence, Biosynthesis, and Pharmacological Properties Including Therapeutic Potential

Calanolides are tetracyclic 4-substituted dipyranocoumarins. Calanolide A, isolated from the leaves and twigs of Calophyllum lanigerum var. austrocoriaceum (Whitmore) P. F. Stevens, is the first member of this group of compounds with anti-HIV-1 activity mediated by reverse transcriptase inhibition. Calanolides are classified pharmacologically as non-nucleoside reverse transcriptase inhibitors (NNRTI). There are at least 15 naturally occurring calanolides distributed mainly within the genus Calophyllum, but some of them are also present in the genus Clausena. Besides significant anti-HIV properties, which have been exploited towards potential development of new NNRTIs for anti-HIV therapy, calanolides have also been found to possess anticancer, antimicrobial and antiparasitic potential. This review article provides a comprehensive update on all aspects of naturally occurring calanolides, including their chemistry, natural occurrence, biosynthesis, pharmacological and toxicological aspects including mechanism of action and structure activity relationships, pharmacokinetics, therapeutic potentials and available patents.

Diverse synthesis of pyrano[3,2-c]coumarins: a brief update

This short review discusses the synthesis of pyrano[3,2-c]coumarins using different strategies including mechanistic illustrations.

Natural Products as a Foundation for Drug Discovery

Many natural products have been used as drugs for the treatment of diverse indications. Although most U.S. pharmaceutical companies have reduced or eliminated their in-house natural-product research over the years, new approaches for compound screening and chemical synthesis are resurrecting interest in exploring the therapeutic value of natural products. The aim of this commentary is to review emerging strategies and techniques that have made natural products a viable strategic choice for inclusion in drug discovery programs. Published 2019. U.S. Government.

Chemodiversity of Calophyllum inophyllum L. oil bioactive components related to their specific geographical distribution in the South Pacific region

Background

Different parts of the tree Calophyllum inophyllum L. (nuts, leaves, roots, bark, fruits, nut oil and resin) are used as traditional medicines and cosmetics in most of the Pacific Islands. The oil efficiency as a natural cure and in traditional cosmetics has been largely described throughout the South Pacific, which led us to investigate C. inophyllum’s chemical and genetic diversity. A correlative study of the nut resin and leaf DNA from three distinct archipelagos in the South Pacific was carried out in order to identify diversity patterns in C. inophyllum across the South Pacific.

Methods

Calophyllum inophyllum plants were sampled from French Polynesia, New Caledonia and Fiji. We extracted tamanu oil (nut oil) resin for chemo-diversity studies and sampled leaf tissues for genetic studies. We applied an analysis method designed for small quantities (at a microscale level), and used High Performance Liquid Chromatography (HPLC) to establish the chemo-diversity of tamanu oil resin. In-house standards were co-eluted for qualitative determination. Genetic diversity was assessed using chloroplast barcoding markers (the Acetyl-CoA carboxylase (accD) gene and the psaA-ycf3 intergenic spacer region).

Results

Our HPLC analysis revealed 11 previously known tamanu oil constituents, with variability among plant samples. We also isolated and characterized two new neoflavonoids from tamanu oil resin namely, tamanolide E1 and E2 which are diastereoisomers. Although genetic analysis revealed low genetic variation, our multivariate analysis (PCA) of the tamanu oil resin chemical profiles revealed differentiation among geographic regions.

Conclusion

We showed here that chromatographic analysis using formalized in-house standards of oil resin compounds for co-elution studies against oil resin samples could identify patterns of variation among samples of C. inophyllum, and discriminate samples from different geographical origins.

Eleutheroside B1 mediates its anti-influenza activity through POLR2A and N-glycosylation

Influenza viruses represent a serious threat to human health. Although our research group has previously demonstrated the antiviral and anti-inflammatory activities of eleutheroside B1, a detailed explanation of the mechanism by which it is effective against the influenza virus remains to be elucidated. In the present study, the transcriptomic responses of influenza A virus-infected lung epithelial cells (A549) treated with eleutheroside B1 were investigated using high-throughput RNA sequencing, and potential targets were identified using a molecular docking technique, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assay, and DNA methylation analysis. The transcriptomic data revealed that there are 1,871 differentially expressed genes (DEGs) between the cells infected with the influenza virus strain variant PR8, and the cells infected with PR8 and treated with eleutheroside B1. Among the DEGs, RNA polymerase II subunit A (POLR2A; encoding the largest subunit of RNA polymerase II) and mannosidase α class II member 1 (MAN2A1) were selected from the molecular docking analysis with eleutheroside B1. The docking score of Drosophila melanogaster MAN2A1 (3BVT) was 11.3029, whereas that of POLR2A was 9.0133. The RT-qPCR results demonstrated that the expression levels of host genes (MAN2A2, POLR2A) and viral genes (PA, PB1, PB2, HA) were downregulated following eleutheroside B1 treatment. Bisulfite-sequencing PCR was performed to investigate whether eleutheroside B1 was able to modify the DNA methylation of POLR2A, and the results suggested that the average proportion of methylated CpGs (-222-72 bp) increased significantly following treatment with eleutheroside B1. Taken together, these findings suggested that eleutheroside B1 may affect N-glycan biosynthesis, the chemokine signaling pathway, cytokine-cytokine receptor interaction and, in particular, may target the POLR2A to inhibit the production of influenza virus genes.

Functionalization of 3-chloroformylcoumarin to coumarin Schiff bases using reusable catalyst: an approach to molecular docking and biological studies

Recently, heterogeneous catalysts have been explored eximiously in the synthesis of heterocyclic compounds. Therefore, here we used solid-supported heterogeneous silica sulfuric acid as a catalyst for the synthesis of Schiff's base of 3-chloroformylcoumarin in view of simplified procedure, reusability and acceptable efficiency, which are required in organic synthesis. An efficient and facile methodology is preferred for synthesis of a class of chromeno-3-substituted derivatives (1a-1l) with good yields. The molecular docking results showed excellent binding interactions with the Mycobacterium tuberculosis InhA-D148G mutant (PDB: 4DQU). The same biomolecules were screened for their in vitro anti-tubercular activity against the M.tb H37Rv strain and antimicrobial studies. Physico-chemistry, toxicity prediction with IC50 value and bioactivity score were also calculated for title compounds. Most active compounds were further tested for cytotoxicity studies and exhibited low-level cytotoxicity against Vero cells. The suggested conjugates are promising lead compounds for the subsequent investigation in search of new anti-tubercular agents. All the conjugates were obtained within the range and followed the Lipinski rule of 5, indicating more 'drug-like' nature.

Natural Products and HIV/AIDS

The study of natural products in biomedical research is not a modern concept. Many of the most successful medical therapeutics are derived from natural products, including those studied in the field of HIV/AIDS. Biomedical research has a rich history of discovery based on screens of medicinal herbs and traditional medicine practices. Compounds derived from natural products, which repress HIV and those that activate latent HIV, have been reported. It is important to remember the tradition in medical research to derive therapies based on these natural products and to overcome the negative perception of natural products as an "alternative medicine."

Inhibition viral RNP and anti-inflammatory activity of coumarins against influenza virus

Influenza viruses pose a severe threat to human health and a significant increase in antiviral drug-resistant among influenza viruses worldwide has been observed. Therefore, there is an urgent need to develop the new antiviral drugs, specifically from the natural products. In this study, the anti-viral and anti-inflammatory activities of coumarins against influenza A virus in vitro were investigated. One of the derivatives eleutheroside B₁ showed a wide spectrum of anti- human influenza virus effect with the IC₅₀ value of 64-125μg/ml in vitro, but it showed no effects against avian influenza virus. The time of addition was done and the results indicated that it had a potent antiviral effect when added at 0-6h, and also the virus yield was reduced by 60%. The influenza virus ribonucleoprotein was inhibited at 200μg/ml, and also the NP mRNA expression was inhibited at 50 and 200μg/ml. The expression level of cytokines and chemokines influenced by eleutheroside B₁ was further demonstrated, the IL-6, CXCL-8, CCL-2 expression were all inhibited by the eleuthe roside B₁ at concentration 200μg/ml. The findings of study suggest that eleutheroside B₁ can be as potential agent to develop for the prevention and treatment of influenza A virus.

Synthesis and biological evaluation of new pyranopyridine derivatives catalyzed by guanidinium chloride-functionalized γ-Fe2O3/HAp magnetic nanoparticles

Herein, we described the synthesis of γ-Fe₂O₃@HAP-GndCl MNPs as an efficient and recyclable nanocatalyst for synthesis of new pyranopyridine derivatives under solvent-free condition and then evaluated for theirs antioxidant and antifungal activities.

Ultrasound mediated, iodine catalyzed green synthesis of novel 2-amino-3-cyano-4H-pyran derivatives

An efficient synthesis of a novel series of twelve substituted 2-amino-3-cyano-4H-pyran derivatives was achieved by a one-pot three-component cyclocondensation reaction of heteroaryl aldehydes, malononitrile and active methylene compounds catalyzed by iodine in aqueous medium under ultrasound irradiation. In comparison with conventional methods, our protocol is convenient and offers several advantages, such as shorter reaction time, higher yields, milder conditions and environmental friendliness. We have herein successfully demonstrated the synergistic outcome of multi-component reaction (MCR) and sonication to offer a facile route for the design of these derivatives.

Lipase-catalyzed regioselective domino reaction for the synthesis of chromenone derivatives

2H-Chromenones and 2-hydroxyl-2H-chromenones were synthesized under BPL- and PFL-catalyzed domino reactions from the same substrates respectively.

Synthesis and structural activity relationship study of antitubercular carboxamides

The unusual structure and chemical composition of the mycobacterial cell wall, the tedious duration of therapy, and resistance developed by the microorganism have made the recurrence of the disease multidrug resistance and extensive or extreme drug resistance. The prevalence of tuberculosis in synergy with HIV/AIDS epidemic augments the risk of developing the disease by 100-fold. The need to synthesize new drugs that will shorten the total duration of effective treatment and/or significantly reduce the dosage taken under DOTS supervision, improve on the treatment of multidrug-resistant tuberculosis which defies the treatment with isoniazid and rifampicin, and provide effective treatment for latent TB infections which is essential for eliminating tuberculosis prompted this review. In this review, we considered the synthesis and structure activity relationship study of carboxamide derivatives with antitubercular potential.

Heteropterys cotinifolia: a neuropharmacological and phytochemical approach with possible taxonomic implications

Heteropterys cotinifolia (Malpighiaceae) has been used in traditional Mexican medicine mainly for the treatment of nervous disorders. However, the specific neuropharmacological activities responsible for this use remain to be defined. The present study evaluates the antidepressant and anxiolytic effects produced by the methanolic extract of Heteropterys cotinifolia and the influence of such effects on motor activity in ICR mice. Our results show that the methanolic extract of Heteropterys cotinifolia produces a dose-dependent antidepressant effect in the forced swimming test in mice at doses from 31 to 310 mg/kg, with no reduction of mice locomotion. However, no anxiolytic properties were observed. Our findings suggest that the main extract compounds identified as chlorogenic acid and rutin may be involved in the antidepressant effects. To our knowledge, the present study constitutes the first report of pharmacological and phytochemical data of Heteropterys cotinifolia. The presence of flavonoids in the methanolic extract of Heteropterys cotinifolia may also provide further data to characterize taxonomically this species in order to be distinguished from others species closely related and belonging to the same genus.

Facile construction of structurally diverse thiazolidinedione-derived compounds via divergent stereoselective cascade organocatalysis and their biological exploratory studies

In this article, we present a new approach by merging two powerful synthetic tactics, divergent synthesis and cascade organocatalysis, to create a divergent cascade organocatalysis strategy for the facile construction of new "privileged" substructure-based DOS (pDOS) library. As demonstrated, notably 5 distinct molecular architectures are produced facilely from readily available simple synthons thiazolidinedione and its analogues and α,β-unsaturated aldehydes in 1-3 steps with the powerful strategy. The beauty of the chemistry is highlighted by the efficient formation of structurally new and diverse products from structurally close reactants under the similar reaction conditions. Notably, structurally diverse spiro-thiazolidinediones and -rhodanines are produced from organocatalytic enantioselective 3-component Michael-Michael-aldol cascade reactions of respective thiazolidinediones and rhodanines with enals. Nevertheless, under the similar reaction conditions, reactions of isorhodanine via a Michael-cyclization cascade lead to structurally different fused thiopyranoid scaffolds. This strategy significantly minimizes time- and cost-consuming synthetic works. Furthermore, these molecules possess high structural complexity and functional, stereochemical, and skeletal diversity with similarity to natural scaffolds. In the preliminary biological studies of these molecules, compounds 4f, 8a, and 10a exhibit inhibitory activity against the human breast cancer cells, while compounds 8a, 9a, and 9b display good antifungal activities against Candida albicans and Cryptococcus neoformans. Notably, their structures are different from clinically used triazole antifungal drugs. Therefore, they could serve as good lead compounds for the development of new generation of antifungal agents.

Comparing conventional and supercritical extraction of (-)-mammea A/BB and the antioxidant activity of Calophyllum brasiliense extracts

Calophyllum brasiliense is a rich source of bioactive coumarins, xanthones and biflavonoids. The aim of the study was to compare the phenol contents and the antioxidant activity of C. brasiliense extracts obtained by conventional and supercritical fluid extraction (SFE) methods, as well as the quantification of crude extracts and (-)-mammea A/BB yields. Dichloromethane and hexane were used as solvents for the conventional extractions and SFE was developed using supercritical CO₂; the kinetic curves were modeled using a second-order empirical model. The dichloromethane extract presented the best total yield, although it showed the lowest content of (-)-mammea A/BB. The concentration of the coumarin was considerably higher in extracts obtained by the supercritical fluid method and a higher antioxidant activity was assigned to extracts obtained by this technique. Concerning the total phenolic contents, both the dichloro-methane and the supercritical extractions produced satisfactory amounts. The SFE method proved to be more promising than conventional methods.

A fast and efficient HPLC-PDA-MS method for detection and identification of pyranochromanone acids in Calophyllum species

Pyranochromanone acids isolated from Calophyllum species have shown a variety of biological potentialities including antioxidant, antiulcer, anticancer and anti-Helicobacter pylori activities. These compounds seem to be the main constituents of Cuban Calophyllum species together xanthones and biflavonoids. Recently, the pyranochromanone acids calophyllic acid, isocalophyllic acid, apetalic acid, calolongic acid, isoapetalic acid, pinetoric acid I, pinetoric acid II, were isolated from Calophyllum pinetorum, a Cuban endemic species. The objective of the present work was the development of a rapid and efficient HPLC-DAD-MS method for fast screening of pyranochromanones in the leaves and resins of different endemic Calophyllum spp of Cuba, without clean-up procedures. For this purpose, a generalized fragmentation pathway was proposed and used to characterize, by HPLC-DAD-MS, the pyranochromanone acids in leaves and resins of different Calophyllum species. The developed method enables to detect also minor compounds in Calophyllum spp. The structures proposed by MS data for these compounds were unambiguous confirmed by 1D and 2D-NMR analysis and three new pyranochromanone acids, isocalolongic acid, pinetoric acid III and isopinetoric acid III, were reported here for the first time.

Antiproliferative activity of trans-avicennol from Zanthoxylum chiloperone var. angustifolium against human cancer stem cells

Zanthoxylum chiloperone var. angustifolium root bark was studied with the aim of finding novel molecules able to overcome cancer stem cell chemoresistance. Purification of a methanol-soluble extract resulted in the isolation of a known pyranocoumarin, trans-avicennol (1). Compound 1 demonstrated antiproliferative activity on glioma-initiating cells, whereas it was inactive on human neural stem cells. trans-Avicennol (1) activated the MAPK/ERK pathway and was also evaluated for its ability to inhibit the enzyme indoleamine-2,3-dioxygenase.

Extraction of plant secondary metabolites

This chapter presents an overview of the preparation of extracts from plants using organic solvents, with emphasis on common problems encountered and methods for their reduction or elimination. In addition to generally applicable extraction protocols, methods are suggested for selectively extracting specific classes of plant-derived compounds, and phytochemical procedures are presented for the detection of classes of compounds encountered commonly during extraction, including selected groups of secondary metabolites and interfering compounds. Successful extraction begins with careful selection and preparation of plant samples and thorough review of the appropriate literature for suitable protocols for a particular class of compounds or plant species. During the extraction of plant material, it is important to minimize interference from compounds that may co-extract with the target compounds, and to avoid contamination of the extract, as well as to prevent decomposition of important metabolites or artifact formation as a result of extraction conditions or solvent impurities.

Inhibition of HIV-1 reverse transcriptase, toxicological and chemical profile of Calophyllum brasiliense extracts from Chiapas, Mexico

Calophyllum species are sources of calanolides, which inhibit human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT). The hexane extract of the leaves from C. brasiliense collected in Soconusco, State of Chiapas, Mexico, analyzed by HPLC showed to contain apetalic acid, calanolides B, and C. It showed potent anti-HIV-1 RT inhibition (IC(50)=20.2 μg/ml), but was not toxic in mice (LD(50)=1.99 g/kg). The histological study of the mice treated at the highest dose revealed no alteration on hepatocytes, and an increase in the number of spleen megakaryocytes. These results suggest this extract is suitable to continue studies for developing a phytodrug against HIV-1.

Mexican medicinal plants used for cancer treatment: pharmacological, phytochemical and ethnobotanical studies

AIM OF THE STUDY

This review provides a summary of Mexican medicinal flora in terms of ethnobotanical, pharmacology, and chemistry of natural products related to anticancer activity.

MATERIALS AND METHODS

Bibliographic investigation was carried out by analyzing recognized books and peer-reviewed papers, consulting worldwide accepted scientific databases from the last five decades. Mexican plants with attributed anti-cancer properties were classified into six groups: (a) plant extracts that have been evaluated for cytotoxic effects, (b) plant extracts that have documented anti-tumoral effects, (c) plants with active compounds tested on cancer cell lines, (d) plants with novel active compounds found only in Mexican species, (e) plants with active compounds that have been assayed on animal models and (f) plants with anti-cancer ethnopharmacological references but without scientific studies.

RESULTS

Three hundred plant species belonging to 90 botanical families used for cancer treatment have been recorded, of which only 181 have been experimentally analyzed. The remaining 119 plant species are in use in empirical treatment of diseases consistent with cancer symptomatology. Only 88 of the plant extracts experimentally studied in in vitro cellular models have demonstrated active cytotoxic effects in at least one cancer cell line, and 14 out of the 88 have also been tested in vivo with the results that one of them demonstrated anti-neoplasic effects. A total of 187 compounds, belonging to 19 types of plant secondary metabolites, have been isolated from 51 plant extracts with active cytotoxic effects, but only 77 of these compounds (41%) have demonstrated cytoxicity. Seventeen of these active principles have not been reported in other plant species. However, only 5 compounds have been evaluated in vivo, and 3 of them could be considered as active.

CONCLUSION

Clearly, this review indicates that it is time to increase the number of experimental studies and to begin to conduct clinical trials with those Mexican plants and its active compounds selected by in vitro and in vivo activities. Also, the mechanisms of action by which plant extracts and their active compounds exert anti-cancer effects remain to be studied.

Phylogeny of the clusioid clade (Malpighiales): evidence from the plastid and mitochondrial genomes

PREMISE OF THE STUDY

The clusioid clade includes five families (i.e., Bonnetiaceae, Calophyllaceae, Clusiaceae s.s., Hypericaceae, and Podostemaceae) represented by 94 genera and ≈1900 species. Species in this clade form a conspicuous element of tropical forests worldwide and are important in horticulture, timber production, and pharmacology. We conducted a taxon-rich multigene phylogenetic analysis of the clusioids to clarify phylogenetic relationships in this clade.

METHODS

We analyzed plastid (matK, ndhF, and rbcL) and mitochondrial (matR) nucleotide sequence data using parsimony, maximum likelihood, and Bayesian inference. Our combined data set included 194 species representing all major clusioid subclades, plus numerous species spanning the taxonomic, morphological, and biogeographic breadth of the clusioid clade.

KEY RESULTS

Our results indicate that Tovomita (Clusiaceae s.s.), Harungana and Hypericum (Hypericaceae), and Ledermanniella s.s. and Zeylanidium (Podostemaceae) are not monophyletic. In addition, we place four genera that have not been included in any previous molecular study: Ceratolacis, Diamantina, and Griffithella (Podostemaceae), and Santomasia (Hypericaceae). Finally, our results indicate that Lianthus, Santomasia, Thornea, and Triadenum can be safely merged into Hypericum (Hypericaceae).

CONCLUSIONS

We present the first well-resolved, taxon-rich phylogeny of the clusioid clade. Taxon sampling and resolution within the clade are greatly improved compared to previous studies and provide a strong basis for improving the classification of the group. In addition, our phylogeny will form the foundation for our future work investigating the biogeography of tropical angiosperms that exhibit Gondwanan distributions.

Antimycobacterial screening of traditional medicinal plants using the microplate resazurin assay

Multidrug-resistant Mycobacterium tuberculosis strains have rapidly become a global health concern. North American First Nations communities have used traditional medicines for generations to treat many pulmonary infections. In this study, we evaluated the antimycobacterial activity of 5 medicinal plants traditionally used as general therapeutics for pulmonary illnesses and specifically as treatments for tuberculosis. Aqueous extracts of Aralia nudicaulis, Symplocarpus foetidus, Heracleum maximum, Juniperus communis, and Acorus calamus were screened for antimycobacterial activity against Bacillus Calmette-Guérin, Mycobacterium avium, and M. tuberculosis H37Ra using the colorimetric microplate resazurin assay. Extracts of Acorus calamus and H. maximum root demonstrated significant antimycobacterial activity comparable to that of the rifampin control (2 microg/mL). Evaluation of the cytotoxicity of these 2 extracts using the MTT assay also showed that the extracts were less toxic to 3 human cell lines than was the DMSO positive control. This study demonstrates that aqueous extracts of the roots of H. maximum and Acorus calamus possess strong in vitro antimycobacterial activity, validates traditional knowledge, and provides potential for the development of urgently needed novel antituberculous therapeutics.