Antibacterial Activities of the Algal Bromophenol Methylrhodomelol Against Pseudomonas aeruginosa.

Methylrhodomelol (1: ) is a bromophenol from the red alga Vertebrata lanosa that has been associated with antimicrobial properties. The aim of the current study was, therefore, to assess the antimicrobial potential of this compound in more detail against the gram-negative pathogen Pseudomonas aeruginosa. 1: exerted weak bacteriostatic activity against different strains when grown in minimal medium, whereas other phenolics were inactive. In addition, 1: (35 and 10 µg/mL) markedly enhanced the susceptibility of multidrug-resistant P. aeruginosa toward the aminoglycoside gentamicin, while it did not affect the viability of Vero kidney cells up to 100 µM. Finally, pyoverdine release was reduced in bacteria treated at sub-inhibitory concentration, but no effect on other virulence factors was observed. Transcriptome analysis of treated versus untreated P. aeruginosa indicated an interference of 1: with bacterial carbon and energy metabolism, which was corroborated by RT-qPCR and decreased ATP-levels in treated bacteria. In summary, the current study characterized the antibacterial properties of methylrhodomelol, revealed its potential as an adjuvant to standard antibiotics, and generated a hypothesis on its mode of action.

Phytochemical analysis and anthelmintic activity of Combretum mucronatum leaf extract against infective larvae of soil-transmitted helminths including ruminant gastrointestinal nematodes.

BACKGROUND: Soil-transmitted helminths (STH) infect more than a quarter of the world's human population. In the absence of vaccines for most animal and human gastrointestinal nematodes (GIN), treatment of infections primarily relies on anthelmintic drugs, while resistance is a growing threat. Therefore, there is a need to find alternatives to current anthelmintic drugs, especially those with novel modes of action. The present work aimed to study the composition and anthelmintic activity of Combretum mucronatum leaf extract (CMLE) by phytochemical analysis and larval migration inhibition assays, respectively. METHODS: Combretum mucronatum leaves were defatted with petroleum ether and the residue was extracted by ethanol/water (1/1) followed by freeze-drying. The proanthocyanidins and flavonoids were characterized by thin layer chromatography (TLC) and ultra-high performance liquid chromatography (UPLC). To evaluate the inhibitory activity of this extract, larval migration assays with STH and GIN were performed. For this purpose, infective larvae of the helminths were, if necessary, exsheathed (Ancylostoma caninum, GIN) and incubated with different concentrations of CMLE. RESULTS: CMLE was found to be rich in flavonoids and proanthocyanidins; catechin and epicatechin were therefore quantified for standardization of the extract. Data indicate that CMLE had a significant effect on larval migration. The effect was dose-dependent and higher concentrations (1000 µg/mL) exerted significantly higher larvicidal effect (P < 0.001) compared with the negative control (1% dimethyl sulfoxide, DMSO) and lower concentrations (≤ 100 µg/ml). Infective larvae of Ascaris suum [half-maximal inhibitory concentration (IC50) = 5.5 µg/mL], Trichuris suis (IC50 = 7.4 µg/mL), and A. caninum (IC50 = 18.9 µg/mL) were more sensitive to CMLE than that of Toxocara canis (IC50 = 310.0 µg/mL), while infective larvae of Toxocara cati were largely unaffected (IC50 > 1000 µg/mL). Likewise, CMLE was active against most infective larvae of soil-transmitted ruminant GIN, except for Cooperia punctata. Trichostrongylus colubriformis was most sensitive to CMLE (IC50 = 2.1 µg/mL) followed by Cooperia oncophora (IC50 = 27.6 µg/mL), Ostertagia ostertagi (IC50 = 48.5 µg/mL), Trichostrongylus axei (IC50 = 54.7 µg/mL), Haemonchus contortus (IC50 = 145.6 µg/mL), and Cooperia curticei (IC50 = 156.6 µg/mL). CONCLUSIONS: These results indicate that CMLE exhibits promising anthelmintic properties against infective larvae of a large variety of soil-transmitted nematodes.

Toward a More Sustainable Sample Preparation in Phytochemistry: Case Studies in Four Subclasses of Alkaloids.

The fact that alkaloids are bases has been the most explored chemical feature of their extraction and purification procedures. The main drawback of these procedures is that they employ undesirable chemicals, with HCl and CH2Cl2 probably being the most commonly employed chemicals in their subsequent steps. This work tested the hypothesis that advantages in recovery efficiency support this common practice. Experiments were conducted in three laboratories, monitoring the alkaloids harmine (1), boldine (2), vincamine (3), and mescaline (4) extracted from Banisteriopsis caapi, Peumus boldus, Vinca minor, and Trichocereus macrogonus var. pachanoi, respectively. The research demonstrated that HCl could be replaced with citric acid (CA) without loss or even better extraction performance. The recommended EtOAc could completely replace CH2Cl2 in three out of four study cases and partially in the fourth case without harming the extraction efficiency. In addition, the alternative solvents tert-amyl methyl ether (TAME) and n-butyl acetate (BuOAc) could enhance the extraction of alkaloids. These results might incentivize natural products laboratories to consider sustainability more routinely, thus being closer to current practices in the pharmaceutical industry, which has been replacing solvents and processes with greener ones.

Alstoboonine, an Ulean-Type Indole Alkaloid from Alstonia boonei Leaves.

Alstonia boonei De Wild is a common plant in West Africa used in traditional medicine for various indications. While the stem bark has frequently been investigated, not much is known about the phytochemistry and bioactivity of the leaves. Within the current study, the major alkaloids of a hydroethanolic leaf extract were therefore isolated and characterized by MS, NMR, and ECD. This led to the identification of alstoboonine 1, a new ulean-type alkaloid, along with eight previously reported indole alkaloids, 15-hydroxyangustilobine A (2), 6,7-seco-angustilobine B (3), 6,7-seco-19,20-α-epoxyangustilobine B (4), alstrostine E (5), alstrostine C (6), alstrostine D (7), 12-methoxyechitamidine (8), and 19-oxo-12-methoxyechitamidine (9). 1 was moderately active in vitro against Plasmodium falciparum NF54 (IC50 6.9 µM), but inactive against other protozoan parasites (Trypanosoma brucei, Trypanosoma cruzi, Leishmania donovani). No significant cytotoxic effects were observed in L6 rat skeletal myoblast cells and MCF-7 breast cancer cells. Similarly, compounds 3 to 9 did not show cytotoxicity in MCF-7 cells. Due to the reported traditional use of the plant as an anthelmintic, the major alkaloids 2, 5, 6, and 8 were tested against the nematode Caenorhabditis elegans. Nematicidal effects were observed for 6 (LC50 400 µM), whereas 2, 5, and 8 were inactive.

Towards the development of analytical monograph specifications for the quality assessment of the medicinal plant Phyllanthus urinaria.

Many people in developing countries rely on herbal remedies for their primary healthcare needs. The challenge however is that several of these products lack proper documentation of quality and safety. To ensure consistent quality, validated methods are needed to establish and control quality attributes associated with identity, purity, and levels of bioactive constituents of the respective herbal materials. The present study focused on Phyllanthus urinaria (PU), a widely used medicinal plant in Ghana and West Africa that lacks the necessary quality control standards. The study aimed to develop an HPTLC identification method, which together with UPLC-ESI-Q-TOF-MS/MS analysis established the identity of PU samples and differentiated PU from other closely related Phyllanthus species. Quantitative UPLC and HPTLC methods were developed to assess the contents of selected active markers in the PU samples, which invariably led to the proposal of acceptance criteria for the active markers. Prior to the content analyses, the sample extraction procedure was optimized through the use of Design of Experiment method. The effects of harvest time and geographic origin on the content of active compounds were demonstrated in the investigations. PU samples were also found to be contaminated with higher levels of pesticides like chlorpyrifos and folpet. Essentially, this study provides analytical protocols, insights into the quality status of PU samples in Ghana, and analytical specifications contained in a drafted monograph for future consideration in regional and subregional African pharmacopoeias.

Anthelmintic Activities of Extract and Ellagitannins from Phyllanthus urinaria against Caenorhabditis elegans and Zoonotic or Animal Parasitic Nematodes.

The aerial parts of Phyllanthus urinaria are used in traditional medicine in West Africa against helminthiasis, but their anthelmintic potential has not been evaluated until now. Within the current study, a hydroacetonic extract (AWE) and fractions and isolated ellagitannins from P. urinaria were, therefore, tested in vitro against Caenorhabditis elegans and the larvae of the animal parasites Toxocara canis, Ascaris suum, Ancylostoma caninum, and Trichuris suis. Compounds 1:  - 13: , mainly representing ellagitannins, were isolated using different chromatographic methods, and their structures were elucidated by HR-MS and 1H/13C-NMR. AWE exerted concentration-dependent lethal effects (LC50 of 2.6 mg/mL) against C. elegans and inhibited larval migration of all animal parasites tested (T. suis L1 IC50 24.3 µg/mL, A. suum L3 IC50 35.7 µg/mL, A. caninum L3 IC50 112.8 µg/mL, T. canis L3 IC50 1513.2 µg/mL). The anthelmintic activity of AWE was mainly related to the polar, tannin-containing fractions. Geraniin 1: , the major ellagitannin in the extract, showed the strongest anthelmintic activity in general (IC50 between 0.6 and 804 µM, depending on parasite species) and was the only compound active against A. caninum (IC50 of 35.0 µM). Furosin 9: was least active despite structural similarities to 1: . Among the parasites tested, Trichuris suis L1 larvae turned out to be most sensitive with IC50 of 0.6, 6.4, 4.0, 4.8, and 2.6 µM for geraniin 1: , repandusinic acid A 3: , punicafolin 8: , furosin 9: , and phyllanthusiin A 10: , respectively.

Development of an Analytical Workflow to Support the Establishment of Monographs in African Pharmacopoeias - Combretum mucronatum Leaves as Example.

Herbal medicines are invaluable in African medicine, but quality and safety are not documented in many cases. Besides controlled farming, validated quality control methods are needed to ensure identity, purity, and content. Analytical specifications within modern monographs are needed for consistent batch quality. Combretum mucronatum leaves are widely used in West Africa, but state-of-the-art quality control methods and specifications are non-existent. The aim of the following study was the development of ICH-validated chromatographic protocols for identity, purity, content assay, and analytical specifications for consideration into pharmacopoeial monographs. UPLC-ESI-Q-TOF-MS/MS was used for untargeted phytochemical information on composition. Optimisation of extraction was based on phytochemical profiling. HPTLC was used for differentiation of C. mucronatum from other Combretum species and UPLC for simultaneous determination of 7 marker compounds. C. mucronatum batch analyses (n = 49) investigated the influence of harvest time and geographical origin. Pesticides screening from a 349-compound panel were carried out. 30 compounds, identified by LC-MS, were used for characterization of the plant material. Orietin, isoorientin, vitexin and isovitexin were used as specific marker compounds for qualitative and quantitative HPTLC purposes, while UPLC quantified additionally epicatechin, procyanidins B2 and C1. Influence of harvest time and geographic origin on the content of marker compounds was observed. Differences in the metabolite profiles of C. mucronatum compared to related Combretum species were established for quality control purposes. Contamination with high amoounts of chlorpyrifos, and folpet (sum of folpet and phtalimide, expressed as folpet) were also observed.The study provides analytical protocols, analytical specifications and a drafted monograph for consideration for African pharmacopoeias, and reveals potential challenges in the quality of C. mucronatum.

Condensed tannins act as anthelmintics by increasing the rigidity of the nematode cuticle.

Tannins and tanniferous plant extracts have been discussed as sustainable means for helminth control in the past two decades in response to a dramatic increase of resistances towards standard anthelmintics. While their bioactivities have been broadly investigated in vitro and in vivo, less is known about their mode of action in nematodes, apart from their protein binding properties. In the current study we therefore investigated the impact of a phytochemically well characterized plant extract from Combretum mucronatum, known to contain procyanidins as the active compounds, on the model organism Caenorhabditis elegans. By different microscopic techniques, the cuticle was identified as the main binding site for tannins, whereas underlying tissues did not seem to be affected. In addition to disruptions of the cuticle structure, molting defects occurred at all larval stages. Finally, an increased rigidity of the nematodes' cuticle due to binding of tannins was confirmed by force spectroscopic measurements. This could be a key finding to explain several anthelmintic activities reported for tannins, especially impairment of molting or exsheathment as well as locomotion.

Quality assessment of African herbal medicine: A systematic review and the way forward.

BACKGROUND: In Africa, herbalism supplements allopathic medicine's efforts to ensure Universal Health Coverage attainment. This review was conducted to identify and to summarise current literature on methodological approaches used for quality control of herbal medicines in Africa, to evaluate the gaps associated with existing strategies within context of best practices, and make recommendations for future improvements. METHODS: A systematic search was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Articles were screened and assessed for eligibility. RESULTS: 118 articles were included into the study. There was a high preference for impurity profiling tests (77%) indicating the prioritization for tests that guarantee safety despite the limited analytical resources available. Other classes of tests reported included identification tests (29%), physicochemical tests (18%), and content assays (12%). Although standard methods exist in preparing samples for impurity tests, different techniques were observed in different studies, and this could lead to differences in analytical outcomes. Content assays focused on single marker assessments, which may be inadequate to comprehensively assess the quality of products. CONCLUSION: This review provides knowledge of existing strengths and challenges for herbal medicine quality assessments in Africa. For future it is recommended to implement more studies on contaminants (e.g. mycotoxins) and pharmaceutical adulterants. The use of chemometrics to develop analytical methods should be promoted. Also, stakeholders in the medicine quality industry in Africa need to effectively collaborate to establish a well co-ordinated and harmonized system to provide a sustainable framework for the GACP and GMP guided production and quality assurance of herbal medicines.

Anti-Inflammatory Potential of Phenolic Compounds Isolated From Entada africana Guill. & Perr. Used in the Republic of Benin.

In West African medicine, Entada africana Guill. & Perr. from the family of Fabaceae is used to treat inflammatory conditions in the management of fractures, wounds, and sprains in the northern region of the Republic of Benin. The aim of the present study was to isolate and elucidate phenolic compounds from a hydroalcoholic leaf extract from E. africana and to identify compounds with anti-inflammatory activity in vitro. Eleven compounds were purified from three fractions, which have shown strong to medium anti-inflammatory activity. The isolated compounds were characterized by HRESI-MS and NMR methods as gallic acid (1), ethyl gallate (2), 5,7-dihydroxychromen-4-one (3), 3',4',7-trihydroxyflavone (4), dihydrokaempferol-7-O-glucoside (5), catechin (6), quercetin-3-O-[ß-apiosyl-(1‴→2″)-ß-glucoside] (7), quercetin-3-O-glucoside (8), naringenin-7-O-glucoside (9), aromadendrin (10), and myricetin-3-O-glucoside (11). Nine of the major phenolic compounds were tested using TNF-α stimulated human keratinocytes (HaCaT) as skin inflammation model to identify molecules, which may explain the use of the plant leaves as an anti-inflammatory remedy by assessing the release of proinflammatory cytokines IL-8 and IL-6. The hydroacoholic leaf extract of E. africana exerted a medium inhibitory effect on the release of IL-8. 3',4',7-trihydroxyflavone, aromadendrin, dihydrokaempferol-7-O-glucoside and ethyl gallate demonstrated a strong to medium effect on the release of IL-6. For the release of IL-8, 3',4',7-trihydroxyflavone demonstrated a medium activity. This study provides for the first time a detailed screening of phenolic compounds occurring in the hydroethanolic leaf extract of E. africana. Additionally, it is shown that E. africana contains active compounds which may justify its traditional medicinal use as an anti-inflammatory remedy to treat inflammatory and pain-related skin conditions in the Republic of Benin.

Anthelmintic Agents from African Medicinal Plants: Review and Prospects.

Soil-transmitted helminthiasis affects more than 1.5 billion people globally and largely remains a sanitary problem in Africa. These infections place a huge economic burden on poor countries and affect livestock production, causing substantial economic losses and poor animal health. The emergence of anthelmintic resistance, especially in livestock, and the potential for its widespread in humans create a need for the development of alternative therapies. Medicinal plants play a significant role in the management of parasitic diseases in humans and livestock, especially in Africa. This report reviews anthelmintic studies that have been conducted on medicinal plants growing in Africa and published within the past two decades. A search was made in various electronic databases, and only full articles in English were included in the review. Reports show that aqueous and hydroalcoholic extracts and polar fractions obtained from these crude extracts form the predominant (80%) form of the extracts studied. Medicinal plants, extracts, and compounds with different chemical groups have been studied for their anthelmintic potential. Polyphenols and terpenoids are the most reported groups. More than 64% of the studies employed in vitro assays against parasitic and nonparasitic nematode models. Egg hatch inhibition, larval migration inhibition, and paralysis are the common parameters assessed in vitro. About 72% of in vivo models involved small ruminants, 15% rodents, and 5% chicken. Egg and worm burden are the main factors assessed in vivo. There were no reports on interventions in humans cited within the period under consideration. Also, few reports have investigated the potential of combining plant extracts with common anthelmintic drugs. This review reveals the huge potential of African medicinal plants as sources of anthelmintic agents and the dire need for in-depth clinical studies of extracts, fractions, and compounds from African plants as anthelmintic agents in livestock, companion animals, and humans.

In vitro screening of plant extracts traditionally used as cancer remedies in Ghana - 15-Hydroxyangustilobine A as the active principle in Alstonia boonei leaves.

ETHNOPHARMACOLOGICAL RELEVANCE: Cancer represents a major health burden and drain on the global healthcare systems. Traditional African medicine widely use a variety of plant species for treatment of different kinds of cancer. A previous systematic survey by traditional healers in the Ashanti region of Ghana revealed a good overview on the plant species and herbal materials used for the different types of cancer. AIMS OF THE STUDY: The following study aimed to investigate 18 herbal materials from 10 plant species based on the cancer survey in Ghana regarding potential cytotoxicity against different cancer cell lines under in vitro conditions followed by subsequent bioassay-guided fractionation towards the active principle. MATERIALS AND METHODS: Ethanol-water (1:1) extracts were tested (1-100 µg/mL) against a panel of cancer cell lines according to their respective traditional use. Selected extracts with relevant cytotoxicity in this screening were also tested against common pediatric malignancies (leukemias (HL-60, REH) and Ewing sarcoma (RD-ES and CADO-ES1)). Bioassay-guided fractionation of the hydroalcoholic extract from Alstonia boonei was performed by liquid-liquid chromatography and preparative HPLC. Preliminary mechanistic studies on the mode of action were performed by flow cytometric cell cycle analysis as well as apoptosis and necrosis staining. RESULTS: Screening of plant extracts revealed relevant cytotoxicity against all tested cancer cell lines for Alstonia boonei leaves and stem of Paulinia pinnata. The A. boonei extract was additionally found to be active against common pediatric tumor types (leukemias and Ewing sarcoma). Bioassay-guided fractionation of the A. boonei extract revealed the presence of 15-hydroxyangustilobine A 1 as the active principle (IC50 26 µM against MCF-7 cells). This is the first report of this compound in A. boonei. 1 was shown to lead to cell cycle arrest in the G2/M-phase (MCF-7 cells), triggering cells at least partially into apoptosis. CONCLUSION: In summary, an appreciable in vitro activity was revealed for the leaf extract from A. boonei and the isolated vallesamine type indole alkaloid 1, which has to be investigated in future studies towards a potential clinical use.

Challenges at the Time of COVID-19: Opportunities and Innovations in Antivirals from Nature.

As viral infections are an increasing threat to human societies, the need for new therapeutic strategies is becoming even more obvious. As no vaccine is available for COVID-19, the development of directly acting antiviral agents and preventive strategies have to be considered. Nature provides a huge reservoir of anti-infectious compounds, from which we can deduce innovative ideas, therapies, and products. Anti-adhesive natural products interact with the receptor-mediated recognition and early interaction of viruses with the host cells, leading to a reduced internalisation of the virus and reduced infections (e.g., procyanidin-B-2-di-O-gallate against influenza and herpes virus). Lignans like podophyllotoxin and bicyclol show strong antiviral activities against different viruses, and essential oils can directly interact with viral membranes and reduce the host's inflammatory responses (e.g., 1,8-cineol). Echinacea extracts stimulate the immune system, and bioavailable alkamides are key players by interacting with immunomodulating cannabinoid receptors. COVID-19 and SARS-CoV-2 infections have, in part, successfully been treated in China by preparations from traditional Chinese medicine and, while it is too early to draw conclusions, some promising data are available. There is huge potential, but intensified research is needed to develop evidence-based medicines with a clearly defined chemical profile. Intensified research and development, and therefore funding, are needed for exploiting nature's reservoir against viral infections. Combined action for basic research, chemistry, pharmacognosy, virology, and clinical studies, but also supply chain, sustainable sourcing, and economic aspects have to be considered. This review calls for intensified innovative science on natural products for the patients and for a healthier world!

Anthelmintic A-Type Procyanidins and Further Characterization of the Phenolic Composition of a Root Extract from Paullinia pinnata.

Extracts from the roots of Paullinia pinnata L. are used in West Africa as traditional remedies for a variety of diseases including infestations with soil-transmitted helminths. Based on the results of an ethnopharmacological survey in Ghana, an aqueous acetone (70%) extract was investigated for its anthelmintic and phytochemical properties. Partitioning of the crude extract followed by several fractionation steps of the ethyl acetate phase using Sephadex® LH-20, fast centrifugal partition chromatography, RP-18-MPLC and HPLC led to isolation of six oligomeric A-type procyanidins (1 to 6). To determine the anthelmintic activity, the crude extract, fractions and isolated compounds were tested in vitro against the model organism Caenorhabditis elegans. A significantly better activity was observed for the trimeric A-type procyanidin (1) compared to a B-type trimer. However, this effect could not be generalized for the tetrameric procyanidins, for which the type of the interflavan-linkage (4→6 vs. 4→8) had the greatest impact on the bioactivity. Besides the procyanidins, three novel compounds, isofraxidin-7-O-α-l-rhamnopyranosyl-(1″→6')-ß-d-glucopyranoside (17), 4-methoxycatechol-2-O-(5''-O-vanilloyl-ß-apiofuranosyl)-(1''→2')-ß-glucopyranoside (18) and a 6-(3-methoxy-4-hydroxyphenyl)-hexane-2,4-diol-2-O-hexoside (19) were isolated together with further ten known compounds (7 to 16), mainly coumarins and coumarinolignans. Except for 3-ß-d-glucopyranosyloxy-4-methyl-2(5H)-furanone (15), none of the isolated compounds has previously been described for P. pinnata. The anthelmintic activity was attributed to the presence of procyanidins, but not to any of the other compound classes. In summary, the findings rationalize the traditional use of P. pinnata root extracts as anthelmintic remedies.

Caenorhabditis elegans revisited by atomic force microscopy - Ultra-structural changes of the cuticle, but not in the intestine after treatment with Combretum mucronatum extract.

Assessing the internal morphology of Caenorhabditis elegans by a topographical technique like atomic force microscopy (AFM) is a challenging process. As a prerequisite for a successful image acquisition, direct contact between the structure of interest and the AFM probe needs to be established. To gain this insight into the morphology of cuticle and intestine in C. elegans before and after treatment with a tannin-enriched hydro-ethanolic extract from Combretum mucronatum, we developed an approach based on polyethylene glycol embedding, ultra-sectioning, de-embedding and hexamethyldisilazane-dehydration prior to measuring in ambient conditions by intermittent contact mode AFM. The used experimental protocol allowed a facile and fast insight into the ultrastructure of treated versus untreated C. elegans individuals, directly leading to the identification of treatment-associated morphological alterations in the cuticle but not the intestine of C. elegans. Additionally, the presented ultra-microtomy based protocol could allow future insight into virtually any tissue or organism by AFM.

An ethnopharmacological survey of medicinal plants traditionally used for cancer treatment in the Ashanti region, Ghana.

AIMS: Cancer represents a major health burden and drain on healthcare resources in the world. The majority of the people of Africa still patronize traditional medicine for their health needs, including various forms of cancer. The aim of the following study is the identification of medicinal plants used for cancer treatment by the traditional healers in the Ashanti area of Ghana and to cross-reference the identified plant species with published scientific literature. METHODOLOGY: Validated questionnaires were administered to 85 traditional healers in 10 communities within Ashanti region. For cross-validation, also 7 healers located outside Ashanti region were investigated to evaluate regional differences. Interviews and structured conversations were used to administer the questionnaires. Selected herbal material dominantly used by the healers was collected and identified. RESULTS: The ethnopharmacological survey revealed 151 plant species used for cancer treatment. Identified species were classified into different groups according to their frequency of use, resulting in the "top-22" plants. Interestingly group I (very frequent use) contained 5 plant species (Khaya senegalensis, Triplochiton scleroxylon, Azadirachta indica, Entandrophragma angolense, Terminalia superba), three of which belong to the plant family Meliaceae, phytochemically mainly characterized by the presence of limonoids. Cross-referencing of all plants identified by current scientific literature revealed species which have not been documented for cancer therapy until now. Special interest was laid on use of plants for cancer treatment of children. CONCLUSION: A variety of traditionally used anti-cancer plants from Ghana have been identified and the widespread use within ethnotraditional medicine is obvious. Further in vitro and clinical studies will be performed in the near future to rationalize the phytochemical and functional scientific background of the respective extracts for cancer treatment.

Transcriptome analysis reveals molecular anthelmintic effects of procyanidins in C. elegans.

Worldwide, more than 1 billion people are affected by infestations with soil-transmitted helminths and also in veterinary medicine helminthiases are a severe threat to livestock due to emerging resistances against the common anthelmintics. Proanthocyanidins have been increasingly investigated for their anthelmintic properties, however, except for an interaction with certain proteins of the nematodes, not much is known about their mode of action. To investigate the anthelmintic activity on a molecular level, a transcriptome analysis was performed in Caenorhabditis elegans after treatment with purified and fully characterized oligomeric procyanidins (OPC). The OPCs had previously been obtained from a hydro-ethanolic (1:1) extract from the leaves of Combretum mucronatum, a plant which is traditionally used in West Africa for the treatment of helminthiasis, therefore, also the crude extract was included in the study. Significant changes in differential gene expression were observed mainly for proteins related to the intestine, many of which were located extracellularly or within cellular membranes. Among the up-regulated genes, several hitherto undescribed orthologues of structural proteins in humans were identified, but also genes that are potentially involved in the worms' defense against tannins. For example, T22D1.2, an orthologue of human basic salivary proline-rich protein (PRB) 2, and numr-1 (nuclear localized metal responsive) were found to be strongly up-regulated. Down-regulated genes were mainly associated with lysosomal activity, glycoside hydrolysis or the worms' innate immune response. No major differences were found between the groups treated with purified OPCs versus the crude extract. Investigations using GFP reporter gene constructs of T22D1.2 and numr-1 corroborated the intestine as the predominant site of the anthelmintic activity. The current findings support previous hypotheses of OPCs interacting with intestinal surface proteins and provide the first insights into the nematode's response to OPCs on a molecular level as a base for the identification of future drug targets.

A Hydroalcoholic Extract from Paullinia pinnata L. Roots Exerts Anthelmintic Activity against Free-Living and Parasitic Nematodes.

Paullinia pinnata is a medicinal plant traditionally used in West Africa against a wide range of diseases including soil-transmitted helminthiases. In this study, a hydroethanolic root extract was investigated for its phytochemical composition and in vitro activity against the free-living nematode Caenorhabditis elegans as well as the larval stages of the parasitic helminths Ancylostoma caninum, Haemonchus contortus, Toxocara cati, and Trichuris vulpis.LC-MS analysis of the ethanol-water (1 : 1) extract revealed epicatechin and different A-type linked oligomeric and polymeric procyanidins as the predominant compounds.Within an in vitro mortality assay, the extract showed a lethal activity against T. cati (LC50 of 112 µg/mL), T. vulpis (LC50 of 17 µg/mL), and C. elegans (LC50 2.5 of mg/mL), but not against A. caninum. Additionally, effects on egg hatching and larval migration of H. contortus were investigated, but no inhibitory activity was observed.Overall, these findings rationalize the traditional use of the root extract from P. pinnata as an anthelmintic remedy and provide insight into the phytochemical composition of the extract.

Bioassay-Guided Fractionation of a Leaf Extract from Combretum mucronatum with Anthelmintic Activity: Oligomeric Procyanidins as the Active Principle.

Combretum mucronatum Schumach. &amp; Thonn. is a medicinal plant widely used in West African traditional medicine for wound healing and the treatment of helminth infections. The present study aimed at a phytochemical characterization of a hydroalcoholic leaf extract of this plant and the identification of the anthelmintic compounds by bioassay-guided fractionation. An EtOH-H2O (1:1) extract from defatted leaves was partitioned between EtOAc and H2O. Further fractionation was performed by fast centrifugal partition chromatography, RP18-MPLC and HPLC. Epicatechin (1), oligomeric proanthocyanidins (OPC) 2 to 10 (mainly procyanidins) and flavonoids 11 to 13 were identified as main components of the extract. The hydroalcoholic extract, fractions and purified compounds were tested in vitro for their anthelmintic activity using the model nematode Caenorhabditis elegans. The bioassay-guided fractionation led to the identification of OPCs as the active compounds with a dose-dependent anthelmintic activity ranging from 1 to 1000 µM. Using OPC-clusters with a defined degree of polymerization (DP) revealed that a DP ≥ 3 is necessary for an anthelmintic activity, whereas a DP > 4 does not lead to a further increased inhibitory effect against the helminths. In summary, the findings rationalize the traditional use of C. mucronatum and provide further insight into the anthelmintic activity of condensed tannins.

An ethnopharmacological survey and in vitro confirmation of the ethnopharmacological use of medicinal plants as anthelmintic remedies in the Ashanti region, in the central part of Ghana.

ETHNOPHARMACOLOGICAL RELEVANCE: Infections with helminths are still a big problem in many parts of the world. The majority of the people in West Africa treat such infections with medicinal plants related to the local traditional medicine. The present study aims at identifying medicinal plants traditionally used for worm infections in the Ashanti region, Ghana. In vitro screening of selected extracts from plants on which scientific knowledge is limited was to be performed. MATERIALS AND METHODS: Validated questionnaires were administered to 50 traditional healers in the Ashanti region, Ghana. Interviews and structured conversations were used to obtain relevant information. Quantitative and qualitative evaluation was performed additionally to structured cross-referencing of the data using SciFinder(®) data base. Selected plant species were used for in vitro testing on anthelmintic activity against the free-living model nematode Caenorhabditis elegans. RESULTS: 35 plant species were recorded for the use in humans and 6 for the use in animals. Plant material most frequently used were the seeds from Carica papaya, mentioned by nearly all healers. The plausibility of most plants used for treatment of infections with helminths was given in most cases by documentation of potential anthelmintic activity in recent scientific literature. 9 species from plants not or scarcely described in literature for this indication were investigated on in vitro activity. A hydroethanolic (1:1) extract of Combretum mucronatum was most active with a survival rate of nematodes of 89% at 0.1mg/mL and 58% at 1mg/mL respectively (levamisole 16%). Extracts of Paullinia pinnata and Phyllanthus urinaria were also assessed to exhibit a minor (85% and 89% respectively at 1mg/mL), but still significant activity. CONCLUSION: Traditional use of anthelmintic plants from Ghana can be well rationalized by cross-referencing with published literature and phytochemical/pharmacological plausibility.The in vitro investigations of extracts from Combretum mucronatum, Paullinia pinnata and Phyllanthus urinaria exhibited significant effects against nematodes. The anthelmintic activity of these plants should be investigated in detail for pinpointing the respective lead structures responsible for the activity.