Vasorelaxing alkaloids and flavonoids from Cassytha filiformis

Aporphine alkaloids and a naphthoquinone derivative from the leaves of Phaeanthus lucidus Oliv. and their α-glucosidase inhibitory activity

Three previously undescribed aporphine alkaloids, phaeanthuslucidines E-G, one previously undescribed naphthoquinone derivative, phaeanthusnaphthoquinone, and three known compounds were isolated from an EtOAc extract of the leaves of Phaeanthus lucidus Oliv. The structures of all previously undescribed compounds were established through extensive spectroscopic investigations and high-resolution mass spectroscopy. The 6aR configuration of phaeanthuslucidines E-G was assigned by comparing their ECD spectra and specific rotation values with the reported known compounds. Some isolated compounds were evaluated for their α-glucosidase inhibitory activity. Among these compounds, phaeanthuslucidine E showed the highest α-glucosidase inhibitory activity with an IC50 value of 17.9 ± 0.4 μM. The molecular docking of phaeanthuslucidine E was further studied.

Medicinal patterns of vines used in Chinese herbal medicine: a quantitative study

ETHNOPHARMACOLOGICAL RELEVANCE

The botanical characteristics of twinning, climbing vine plants conceptually take shape to interlink the meridians and collaterals system throughout the human body by expelling climatic evils (e.g., wind, dampness). Thus, vines have displayed great medicinal properties in traditional Chinese medicine (TCM).

AIM OF THE STUDY

Although some popular vine species have been intensively investigated, the comparable features and medicinal specifications among a vast collection of taxonomic groups based on data visualization methods are relatively lacking in attention. Moreover, the translatability of vines from ancient ethnomedical evidence to modern medical system has not been well established. This review tends to quantitatively summarize the strength of vines in healthcare from the perspectives of medicinal part, traditional function, clinical spectrum, phytochemistry divergence, pharmacological attributes, toxicity as well as the progress of proprietary drug development.

MATERIALS AND METHODS

Medicinal vines were retrieved from databases of drug standards and curated catalogues. Synonyms of plant origin across different datasets were normalized by accepted scientific names in the World Flora Online. The distribution patterns and rank of plant origin, medicinal parts, traditional functions and target conditions, as well as the correlation between phytochemical composition and clinical applications were analyzed and visualized.

RESULTS

A total of 121 crude drugs from 36 families, 77 genera, 133 species of vines were obtained and analyzed. The Fabaceae, Menispermaceae and Rubiaceae were the highest ranked families of medicinal vines. Not surprisingly, stem was the most dominant medical part. Moreover, "eliminate wind" displayed a hub node in the traditional function co-occurrence network. In addition to joint impediment disorders, these vines particularly displayed a wide range of therapeutic modalities toward conditions from various organ systems. Chemotaxonomic properties-oriented phytochemical analysis was performed and the chemical diversity among medicinal vines complementarily determined a certain group of therapeutic domains. Particularly, the anti-inflammatory effect and antiarthritic effect were highlighted for treating rheumatic diseases. Using integral animal models and cultured cells, modern pharmacological actions of medicinal vines have been largely observed and validated according to their traditional ethnopharmacology. Furthermore, a small proportion of vine species are well-known toxic plants. Successful drug development pipelines in rheumatic, cardiovascular, liver, malignant and infectious diseases have offered the capacity to generate new treatment options that are being sought out from vine plants.

CONCLUSIONS

Medicinal vines are rich sources of Chinese Material Medica (CMM) and good fit for a variety of clinical manifestations beyond arthritis and rheumatic diseases. In addition to stem, other parts are also popular for both medicines and dietary supplements. Vine plants provide extensive biologically relevant chemical space for developing value-creating drugs. Thus, our analysis can be useful for further motivating and strengthening the preclinical and clinical research of vine-derived remedies.

Comparative analyses of eight complete plastid genomes of two hemiparasitic Cassytha vines in the family Lauraceae

Cassytha is the sole genus of hemiparasitic vines (ca. 20 spp.) belonging to the Cassytheae tribe of the Lauraceae family. It is extensively distributed in tropical and subtropical regions. In this study, we determined the complete plastid genome sequences of C. filiformis and C. larsenii, which do not possess the typical quadripartite structure. The length of C. filiformis plastomes ranged from 114,215 to 114,618 bp, whereas that of C. larsenii plastomes ranged from 114,900 to 114,988 bp. Comparative genomic analysis revealed 1,013 mutation sites, four large intragenomic deletions, and five highly variable regions in the eight plastome sequences. Phylogenetic analyses based on 61 complete plastomes of Laurales species, 19 ITS sequences, and trnK barcodes from 91 individuals of Cassytha spp. confirmed a non-basal group comprising individuals of C. filiformis, C. larsenii, and C. pubescens in the family Lauraceae and proposed a sister relationship between C. filiformis and C. larsenii. Further morphological comparisons indicated that the presence or absence of hairs on the haustoria and the shape or size of fruits were useful traits for differentiating C. filiformis and C. larsenii.

Chemistry and biology of ent-morphinan alkaloids

Morphinan alkaloids have attracted constant attention since the isolation of morphine by Sertürner in 1805. However, a group of 45 compounds possessing a complete ent-morphinan backbone can also be found in the literature. These compounds are related to the morphinandienone subgroup and display a substitution pattern which is different from the morphinans. In particular, these alkaloids could be substituted at position C-2 and C-8 either by a hydroxy function or a methoxy moiety. Four groups of ent-morphinan alkaloids can be proposed, the salutaridine, pallidine, cephasugine and erromangine series. Interestingly, the botanical distribution of the ent-morphinans is more widespread than for the morphinans and includes the Annonaceae, Berberidaceae, Euphorbiaceae, Fumariaceae, Hernandiaceae, Lauraceae, Menispermaceae, Monimiaceae, Papaveraceae, and Ranunculaceae families. To date, their exact mode of production remains elusive and their interplay with the biosynthetic pathway of other classes of benzyltetrahydroisoquinoline alkaloids, in particular aporphines, should be confirmed. Exploration of the biological and therapeutic potential of these compounds is limited to some areas, namely central nervous system (CNS), inflammation, cancer, malaria and viruses. Further studies should be conducted to identify the cellular/molecular targets in view of promoting these compounds as new scaffolds in medicinal chemistry.

A survey on the potential contribution of Reunion Island dye plant species diversity to the market demand for bioactive plant-based dyes and pigments

BACKGROUND

Proven toxicity and environmental burdens caused by artificial dyes have motivated dyeing industries to turn to natural alternatives. Plant-based dyestuffs are an interesting group of alternative crops. Reunion Island located in the Indian Ocean is the only European region in the southern hemisphere. It has a great number of assets to find new molecules in the abundant plant biodiversity. However, the dye-producing plants diversity in this island had not been documented to date.

METHODOLOGY

The assessment of the Reunion Island's plant biodiversity through the "PLANTIN" project allowed us to establish here the first ethnobotanical inventory of plants growing on Reunion Island which may have promising properties as a new alternative source of dyes or colorants for the industries. First, an ethnobotanical survey focused on the uses of plants traditionally used in dyeing was conducted on local stakeholders. Then, the importance of different criteria (e.g., endemicity, accessibility and cultivability, plant organs used for the extraction, industrial interests of the species, etc.) has been considered to establish a classification method of the species, to finally select the most interesting plants which have been further harvested and investigated for their coloring property and dyeing application on natural fibers.

RESULTS

The results showed that local people have accumulated traditional knowledge of dyeing plants, but that this approach had been discontinued in Reunion. The uses of 194 plant species potentially rich in dyes or pigments, belonging to 72 different families, with diverse botanical status (endemic, native, introduced or alien-invasive species) have been recorded. Then, 43 species were harvested and their coloring property were investigated. It demonstrated that dyes extracted from promising species, e.g., Terminalia bentzoe, Weinmannia tinctoria, Thespesia populnea, Erythroxylum laurifolium, Morinda citrifolia, Leea guinensis, Ochrosia borbonica, Danais fragrans, Terminalia cattapa, Casuarina equisetifolia, and Coccoloba uvifera, amongst others, could be used as new textile dyes. Their efficacy in the wool and cotton dyeing has been successfully demonstrated here.

CONCLUSION

These plant-based dyestuffs showed promising coloring properties with different shades that could meet industrial application requirement. It's an area that could promote local cultural inheritance, create opportunity for business and farmers, and that can make a significant contribution to preserving endangered native species by supporting reforestation schemes. Additional researches are in progress to evaluate the safety of these plant-based colored extracts, their chemical composition and biological activities.

13C NMR spectroscopic data of aporphine alkaloids

This study involves aporphine alkaloids identified through ¹³C Nuclear Magnetic Resonance (NMR) spectroscopic data. For the present publication, articles were selected from several databases on aporphine alkaloids from 1994 to 2021. In this class, more than 700 compounds have been registered, with 221 were included in this section, among which 122 were characterized for the first time in the investigated period. The study also addresses their biosynthetic pathways, classifying substances according to their structural characteristics based on established literature. Furthermore, pharmacological activities related to the aporphine alkaloids highlighted in this section are also presented, giving an overview of the various applications of these compounds.

Review on Ethnobotany and phytochemistry of Cassytha filiformis

Traditional medicine has a lot to give towards the world’s health, especially now that limits to conventional pharmacology has occurred. New scientific methodologies may spark a rebirth in global health research and development if rich and developing countries pooled their research capacities with inequitable collaborations. The Cassytha Filiformis has many medicinal uses. It is a parasite plant that has been used for medicinal purposes and other ornamental purposes in many parts of the world, and has found employment in Siddha, European, Ayurveda and Chinese folk medicine. In this review, the ethnobotany, phytochemistry and pharmacological benefits of Cassytha filiformis are discussed.

Stephalagine, an aporphinic alkaloid with therapeutic effects in acute gout arthritis in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Gout is an inflammatory disease characterized by the accumulation of monosodium urate crystals (MSU) in the joints, leading to severe pain and inflammation. Stephalagine is a Brazilian Savanna aporphine alkaloid isolated from Annona crassiflora Mart. Fruit peel, that has been popularly used to treat rheumatism and have been described with antinociceptive properties. However, no studies evaluated the possible therapeutic properties of stephalagine in arthritic pain.

AIM OF THE STUDY

To evaluate the possible antinociceptive and anti-inflammatory effects of stephalagine in an acute gout attack in mice.

MATERIALS AND METHODS

Adult male wild type C57BL/6/J/UFU mice (20-25 g) were used (process number 018/17). The treated group received stephalagine (1 mg/kg, by gavage) and the vehicle group received saline (10 mL/kg, by gavage), both 1 h before the MSU crystals (100 μg/ankle joint) administration. All groups were analyzed for mechanical allodynia, thermal hyperalgesia, overt pain-like behaviors, and edema development at 2, 4, 6 and 24 h after injections. Synovial fluid and the ankle articulation from the injected joint were collected 4 h after administrations for myeloperoxidase enzyme activity, IL-1β measurement, and histological analysis.

RESULTS

Stephalagine had a significant antinociceptive effect on mechanical allodynia, when compared to vehicle group at 2-24 h after intra-articular injection of MSU and 2 h for spontaneous and cold thermal sensitivity. Stephalagine was also able to significantly reduce the articular edema (45 ± 1%), the activity of the myeloperoxidase enzyme (37 ± 6%), and IL-1β levels (43 ± 3%). The histological analysis confirms that stephalagine dramatically reduced the number of infiltrating inflammatory cells (75 ± 6%) in MSU injected animals. Also, stephalagine treatment did not alter the uric acid levels, xanthine oxidase activity, AST and ALT activities, urea and creatinine levels, neither cause any macroscopic changes in the mice's weight, deformations, changes in the coat, or feces.

CONCLUSION

Stephalagine may be an alternative for the management of gout, once it was able to induce antinociceptive and anti-inflammatory effects without causing adverse effects on the evaluated parameters.

Vascular Epiphytic Medicinal Plants as Sources of Therapeutic Agents: Their Ethnopharmacological Uses, Chemical Composition, and Biological Activities

This is an extensive review on epiphytic plants that have been used traditionally as medicines. It provides information on 185 epiphytes and their traditional medicinal uses, regions where Indigenous people use the plants, parts of the plants used as medicines and their preparation, and their reported phytochemical properties and pharmacological properties aligned with their traditional uses. These epiphytic medicinal plants are able to produce a range of secondary metabolites, including alkaloids, and a total of 842 phytochemicals have been identified to date. As many as 71 epiphytic medicinal plants were studied for their biological activities, showing promising pharmacological activities, including as anti-inflammatory, antimicrobial, and anticancer agents. There are several species that were not investigated for their activities and are worthy of exploration. These epipythes have the potential to furnish drug lead compounds, especially for treating cancers, and thus warrant indepth investigations.

Alkaloids of the Lauraceae

This chapter presents an overview of the chemistry and pharmacology of the alkaloids found in species of the Lauraceae family. The occurrence of alkaloids from Lauraceae species as well as their chemical structures is summarized in informative and easy-to-understand tables. Within the Lauraceae family, the genera Ocotea (195), Litsea (180), Cryptocarya (133), and Neolitsea (110) have led to the greater number of publications regarding alkaloids content. Valuable and comprehensive information about the structure of these alkaloids is provided. The alkaloids of the aporphine type, found in 22 of the 23 genera, represent the predominant group in this family. Many of the isolated alkaloids exhibit unique structures. From plants of this family, 22 different types of skeletons have been isolated, among them only the purine alkaloids are classified as pseudoalkaloids, and the types phenethylamines, phenethylcinnamides, and phthalidoisoquinoline are classified as protoalkaloids. The chapter is presented as a contribution for the scientific community, mainly to enable the search for alkaloids in species belonging to the Lauraceae family.

Composition and Chemical Variability of Essential Oils Isolated from Aerial Parts of Cassytha filiformis from Côte d'Ivoire

The essential oils isolated from aerial parts of Cassytha filiformis L. harvested in five locations of Côte d'Ivoire were analyzed by GC(RI), GC-MS and 13C-NMR. The oils were dominated by sesquiterpene derivatives and the content of the main components varied substantially from sample to sample: (E)-β-caryophyllene (1.5-34.9%), bicyclogermacrene (1.0-25.8%), α-humulene (0.5-22.0%), spathulenol (1.0-18.5%) and germacrene D (6.6-16.6%). Two compositions could be distinguished: (i) bicyclogermacrene, germacrene D, spathulenol (2/5 samples) and (ii), (E)-β-caryophyllene, α-humulene (3/5 samples).

Alcaloides aporfínicos con actividad antituberculosa aislados de Ocotea discolor Kunth (Lauraceae)

La tuberculosis causa miles de muertes a nivel mundial y que, actualmente, los fármacos usados no son suficientes y en ocasiones son obsoletos para su tratamiento, se hace necesaria la búsqueda de nuevos compuestos que ayuden a combatirla. Por tanto, se evaluó la actividad antituberculosis de los alcaloides ocoxilonina (1), ocoteina (2), dicentrina (3) y 1,2-metilendioxi-3, 10,11-trimetoxiaporfina (4), aislados de la madera de Ocotea discolor. Las estructuras fueron identificadas por medio del análisis de los datos espectroscópicos de resonancia magnética nuclear (NMR 1D – 1H, 13C, 2D – COSY, HSQC y HMBC), espectros de masas y comparación con datos de la literatura. Todos los compuestos aislados demostraron actividad antituberculosa, con un rango de variación en la concentración mínima inhibitoria entre 140 y 310 μM, siendo la ocoteina (2) la más activo contra la cepa virulenta de Mycobacterium tuberculosis H37Rv.

Chemical constituents and bioactivity of Formosan lauraceous plants

Taiwan is rich in lauraceous plants. A review of 197 references based on the chemical analysis and bioactivity of indigenous lauraceous plants carried out by native scientists from 1963 to 2014 has been compiled. About 303 new compounds and thousands of known compounds comprising alkaloids and non-alkaloids with diverse structures have been isolated or identified from indigenous plants belonging to the 11 lauraceous genera. The volatile components, however, have been excluded from this review. This review provides an overview of the past efforts of Taiwan scientists working on secondary metabolites and their bioactivity in native lauraceous plants. The potential of lauraceous plants worthy of further study is also noted. The contents will be helpful for the chemotaxonomy of Lauraceae and be of value for the development of native Formosan lauraceous plants.

Arboridinine, a Pentacyclic Indole Alkaloid with a New Cage Carbon-Nitrogen Skeleton Derived from a Pericine Precursor

A new monoterpene indole alkaloid characterized by an unprecedented pentacyclic cage skeleton, arboridinine (1), was isolated from a Malaysian Kopsia species. The structure and absolute configuration of the alkaloid were determined based on NMR, MS, and X-ray diffraction analysis. A possible biogenetic pathway from a pericine precursor is presented.

The use of plants in the traditional management of diabetes in Nigeria: pharmacological and toxicological considerations

ETHNOPHARMACOLOGICAL RELEVANCE

The prevalence of diabetes is on a steady increase worldwide and it is now identified as one of the main threats to human health in the 21st century. In Nigeria, the use of herbal medicine alone or alongside prescription drugs for its management is quite common. We hereby carry out a review of medicinal plants traditionally used for diabetes management in Nigeria. Based on the available evidence on the species׳ pharmacology and safety, we highlight ways in which their therapeutic potential can be properly harnessed for possible integration into the country׳s healthcare system.

MATERIALS AND METHODS

Ethnobotanical information was obtained from a literature search of electronic databases such as Google Scholar, Pubmed and Scopus up to 2013 for publications on medicinal plants used in diabetes management, in which the place of use and/or sample collection was identified as Nigeria. 'Diabetes' and 'Nigeria' were used as keywords for the primary searches; and then 'Plant name - accepted or synonyms', 'Constituents', 'Drug interaction' and/or 'Toxicity' for the secondary searches.

RESULTS

The hypoglycemic effect of over a hundred out of the 115 plants reviewed in this paper is backed by preclinical experimental evidence, either in vivo or in vitro. One-third of the plants have been studied for their mechanism of action, while isolation of the bioactive constituent(s) has been accomplished for twenty three plants. Some plants showed specific organ toxicity, mostly nephrotoxic or hepatotoxic, with direct effects on the levels of some liver function enzymes. Twenty eight plants have been identified as in vitro modulators of P-glycoprotein and/or one or more of the cytochrome P450 enzymes, while eleven plants altered the levels of phase 2 metabolic enzymes, chiefly glutathione, with the potential to alter the pharmacokinetics of co-administered drugs.

CONCLUSION

This review, therefore, provides a useful resource to enable a thorough assessment of the profile of plants used in diabetes management so as to ensure a more rational use. By anticipating potential toxicities or possible herb-drug interactions, significant risks which would otherwise represent a burden on the country׳s healthcare system can be avoided.

Ethnobotany, phytochemistry and pharmacology of Stephania rotunda Lour

ETHNOPHARMACOLOGICAL RELEVANCE

Stephania rotunda Lour. (Menispermaceae) is an important traditional medicinal plant that is grown in Southeast Asia. The stems, leaves, and tubers have been used in the Cambodian, Lao, Indian and Vietnamese folk medicine systems for years to treat a wide range of ailments, including asthma, headache, fever, and diarrhoea.

AIM OF THE REVIEW

To provide an up-to-date, comprehensive overview and analysis of the ethnobotany, phytochemistry, and pharmacology of Stephania rotunda for its potential benefits in human health, as well as to assess the scientific evidence of traditional use and provide a basis for future research directions.

MATERIAL AND METHODS

Peer-reviewed articles on Stephania rotunda were acquired via an electronic search of the major scientific databases (Pubmed, Google Scholar, and ScienceDirect). Data were collected from scientific journals, theses, and books.

RESULTS

The traditional uses of Stephania rotunda were recorded in countries throughout Southeast Asia (Cambodia, Vietnam, Laos, and India). Different parts of Stephania rotunda were used in traditional medicine to treat about twenty health disorders. Phytochemical analyses identified forty alkaloids. The roots primarily contain l-tetrahydropalmatine (l-THP), whereas the tubers contain cepharanthine and xylopinine. Furthermore, the chemical composition differs from one region to another and according to the harvest period. The alkaloids exhibited approximately ten different pharmacological activities. The main pharmacological activities of Stephania rotunda alkaloids are antiplasmodial, anticancer, and immunomodulatory effects. Sinomenine, cepharanthine, and l-stepholidine are the most promising components and have been tested in humans. The pharmacokinetic parameters have been studied for seven compounds, including the three most promising compounds. The toxicity has been evaluated for liriodenine, roemerine, cycleanine, l-tetrahydropalmatine, and oxostephanine.

CONCLUSION

Stephania rotunda is traditionally used for the treatment of a wide range of ailments. Pharmacological investigations have validated different uses of Stephania rotunda in folk medicine. The present review highlights the three most promising compounds of Stephania rotunda, which could constitute potential leads in various medicinal fields, including malaria and cancer.

Lauraceae alkaloids

Lauraceae is one of the most representative botanical families, presenting 67 genera, with over 2500 species and more than 300 different alkaloids reported, mainly isoquinolines.

Plant derived aporphinic alkaloid S-(+)-dicentrine induces antinociceptive effect in both acute and chronic inflammatory pain models: evidence for a role of TRPA1 channels

S-(+)-dicentrine is an aporphinic alkaloid found in several plant species, mainly from Lauraceae family, which showed significant antinociceptive activity in an acute model of visceral pain in mice. In this work, we extended the knowledge on the antinociceptive properties of S-(+)-dicentrine and showed that this alkaloid also attenuates mechanical and cold hypersensitivity associated with cutaneous inflammation induced by Complete Freund's Adjuvant in mice. Given orally, S-(+)-dicentrine (100 mg/kg) reversed CFA-induced mechanical hypersensitivity, evaluated as the paw withdrawal threshold to von Frey hairs, and this effect lasted up to 2 hours. S-(+)-dicentrine also reversed CFA-induced cold hypersensitivity, assessed as the responses to a drop of acetone in the injured paw, but did not reverse the heat hypersensitivity, evaluated as the latency time to paw withdrawal in the hot plate (50°C). Moreover, S-(+)-dicentrine (100 mg/kg, p.o.) was effective in inhibit nociceptive responses to intraplantar injections of cinnamaldehyde, a TRPA1 activator, but not the responses induced by capsaicin, a TRPV1 activator. When administered either by oral or intraplantar routes, S-(+)-dicentrine reduced the licking time (spontaneous nociception) and increased the latency time to paw withdrawal in the cold plate (cold hypersensitivity), both induced by the intraplantar injection of cinnamaldehyde. Taken together, our data adds information about antinociceptive properties of S-(+)-dicentrine in inflammatory conditions, reducing spontaneous nociception and attenuating mechanical and cold hypersensitivity, probably via a TRPA1-dependent mechanism. It also indicates that S-(+)-dicentrine might be potentially interesting in the development of new clinically relevant drugs for the management of persistent pain, especially under inflammatory conditions.

Vasorelaxant Alkaloids from Spirospermum penduliflorum (Menispermaceae), a Plant Used to Treat Hypertension in Malagasy Traditional Medicine

Spirospermum penduliflorum Thouars (Menispermaceae) is widely used on the eastern coast of Madagascar to treat hypertension. The aim of the present study was to analyse the vasorelaxant properties of different leaf extracts. The activity of the n-hexane, dichloromethane and methanolic extracts was tested on phenylephrine-contracted aorta. The dichloromethane extract was shown to be the most effective. Further fractionation of this extract led to the isolation of an active fraction relaxing phenylephrine-contracted aorta with an IC50 of 0.18 μg/mL {log IC50 (μg/mL) −0.74 ± 0.03} but was much less effective on KCl induced contractions. Bioassay-guided fractionation of this fraction led to the isolation of two aporphinoid alkaloids, neolitsine and dicentrine, which at concentrations of 0.1 μM and 1 μM displaced to the right the phenylephrine concentration-contraction curve. Our results show that Spirospermum penduliflorum extracts possess vasorelaxant activity in vitro that could be related to the presence of dicentrine in the extracts having an α1 antagonist activity. This finding is not in accord with the previous studies by Rasoanaivo et al where no alkaloids were detected in the leaves of Spirospermum penduliflorum.

Anti-protozoal activity of aporphine and protoberberine alkaloids from Annickia kummeriae (Engl. & Diels) Setten & Maas (Annonaceae)

BACKGROUND

Malaria, trypanosomiasis and leishmaniasis have an overwhelming impact in the poorest countries in the world due to their prevalence, virulence and drug resistance ability. Currently, there is inadequate armory of drugs for the treatment of malaria, trypanosomiasis and leishmaniasis. This underscores the continuing need for the discovery and development of new anti-protozoal drugs. Consequently, there is an urgent need for research aimed at the discovery and development of new effective and safe anti-plasmodial, anti-trypanosomal and anti-leishmanial drugs.

METHODS

Bioassay-guided chromatographic fractionation was employed for the isolation and purification of antiprotozoal alkaloids.

RESULTS

The methanol extract from the leaves of Annickia kummeriae from Tanzania exhibited a strong anti-plasmodial activity against the multi-drug resistant Plasmodium falciparum K1 strain (IC50 0.12 ± 0.01 μg/ml, selectivity index (SI) of 250, moderate activity against Trypanosoma brucei rhodesiense STIB 900 strain (IC50 2.50 ± 0.19 μg/ml, SI 12) and mild activity against Leishmania donovani axenic MHOM-ET-67/82 strain (IC50 9.25 ± 0.54 μg/ml, SI 3.2). Bioassay-guided chromatographic fractionation led to the isolation of four pure alkaloids, lysicamine (1), trivalvone (2), palmatine (3), jatrorrhizine (4) and two sets of mixtures of jatrorrhizine (4) with columbamine (5) and palmatine (3) with (-)-tetrahydropalmatine (6). The alkaloids showed low cytotoxicity activity (CC50 30 - >90 μg/ml), strong to moderate anti-plasmodial activity (IC50 0.08 ± 0.001 - 2.4 ± 0.642 μg/ml, SI 1.5-1,154), moderate to weak anti-trypanosomal (IC50 2.80 ± 0.001 - 14.3 ± 0.001 μg/ml, SI 2.3-28.1) and anti-leishmanial activity IC50 2.7 ± 0.001 - 20.4 ± 0.003 μg/ml, SI 1.7-15.6).

CONCLUSION

The strong anti-plasmodial activity makes these alkaloids good lead structures for drug development programs.

Isoquinolines from the roots of Thalictrum flavum L. and their evaluation as antiparasitic compounds

Alkaloids from Thalictrum flavum L. (Ranuculaceae) growing in the Loire valley (France) were isolated and evaluated for their antiplasmodial and leishmanicidal activities. Berberine was identified as a major component but its analogue, pseudoberberine, was isolated for the first time from this plant. As far as bisbenzylisoquinolines are concerned, thalfoetidine was also isolated and, besides, its nor- derivative, northalfoetidine, was identified as a new compound. Previously isolated alkaloids from Thalictrum species such as northalidasine, northalrugosidine, thaligosidine, thalicberine, thaliglucinone, preocoteine, O-methylcassythine and armepavine were newly described in the roots of T. flavum. Tertiary isoquinolines, and particularly bisbenzylisoquinolines, were found to be leishmanicidal against L. major. Thalfoetidine appeared as the most potent but its new nor- derivative northalfoetidine, as well as northalidasine, were of particular interest due to the fact that their potential leishmanicidal activity was not associated to a strong cytotoxicity.

Larvicidal activity against Aedes aegypti of some plants native to the West-Central region of Brazil

A total of 42 ethanolic extracts from 30 different plant species, native to the Pantanal and Cerrado of the West-Central region of Brazil, have been evaluated for their larvicidal activity against Aedes aegypti larvae, the vector of dengue and dengue hemorrhagic fevers. Among the extracts tested, that obtained from the trunk bark of Ocotea velloziana was the most active. Using a bioassay-directed fractionation of this extract, the active constituent was isolated and characterized as the aporphine alkaloid (+)-dicentrine. Its structure was established on the basis of (1)H and (13)C NMR spectra, optical rotation and by comparison with an authentic sample. This is the first report on the larvicidal activity against A. aegypti of this alkaloid. Our results suggest that (+)-dicentrine may be considered as a promising natural mosquito larvicidal agent.