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A new vobasine–tryptamine-based monoterpene indole alkaloid pseudodimer was isolated from the stem bark of Voacanga africana. As a minor constituent occurring in a thoroughly investigated plant, this molecule was targeted based on a molecular networking strategy and a rational MS2-guided phytochemical investigation led to its isolation. Its structure was formally established based on HRMS, 1D/2D NMR data, and the application of the tool Small Molecule Accurate Recognition Technology (SMART 2.0). Its absolute configuration was assigned by the exciton chirality method and TD-DFT ECD calculations. Besides featuring an unprecedented intermonomeric linkage in the small group of vobasine/tryptamine hybrids, pyrrovobasine also represents the first pyrraline-containing representative in the whole monoterpene indole alkaloids group. Biosynthetic hypotheses possibly underpinning these structural oddities are proposed here.

The Apocynaceae tree Voacanga thouarsii, native to southern Africa and Madagascar, produces monoterpene indole alkaloids (MIA), which are specialized metabolites with a wide range of bioactive properties. Voacanga species mainly accumulates tabersonine in seeds making these species valuable medicinal plants currently used for industrial MIA production. Despite their importance, the MIA biosynthesis in Voacanga species remains poorly studied. Here, we report the first genome assembly and annotation of a Voacanga species. The combined assembly of Oxford Nanopore Technologies long-reads and Illumina short-reads resulted in 3,406 scaffolds with a total length of 1,354.26 Mb and an N50 of 3.04 Mb. A total of 33,300 protein-coding genes were predicted and functionally annotated. These genes were then used to establish gene families and to investigate gene family expansion and contraction across the phylogenetic tree. A transposable element (TE) analysis showed the highest proportion of TE in Voacanga thouarsii compared with all other MIA-producing plants. In a nutshell, this first reference genome of V. thouarsii will thus contribute to strengthen future comparative and evolutionary studies in MIA-producing plants leading to a better understanding of MIA pathway evolution. This will also allow the potential identification of new MIA biosynthetic genes for metabolic engineering purposes.

Two new bisindole alkaloids, 12'-O-demethyl-vobtusine-5-lactam and isovobtusine-N-oxide (1 and 2), were isolated from the leaves of Voacanga grandifolia, together with two known bisindole alkaloids. Their structures were elucidated on the basis of 1D and 2D NMR data. 1 and 2 showed potent antimalarial activity against Plasmodium falciparum 3D7 and very low cytotoxic activity against a human cell line, HepG2 cells.

Voatriafricanines A and B (

A new iboga-vobasine-type isomeric bisindole alkaloid named voacamine A (1), along with eight known compounds&mdash, voacangine (2), voacristine (3), coronaridine (4), tabernanthine (5), iboxygaine (6), voacamine (7), voacorine (8) and conoduramine (9)&mdash, were isolated from the stem bark of Voacangaafricana. The structures of the compounds were determined by comprehensive spectroscopic analyses. Compounds 1, 2, 3, 4, 6, 7 and 8 were found to inhibit the motility of both the microfilariae (Mf) and adult male worms of Onchocerca ochengi, in a dose-dependent manner, but were only moderately active on the adult female worms upon biochemical assessment at 30 &mu, M drug concentrations. The IC50 values of the isolates are 2.49&ndash, 5.49 &micro, M for microfilariae and 3.45&ndash, 17.87 &micro, M for adult males. Homology modeling was used to generate a 3D model of the O. ochengi thioredoxin reductase target and docking simulation, followed by molecular dynamics and binding free energy calculations attempted to offer an explanation of the anti-onchocercal structure&ndash, activity relationship (SAR) of the isolated compounds. These alkaloids are new potential leads for the development of antifilarial drugs. The results of this study validate the traditional use of V. africana in the treatment of human onchocerciasis.

Fourteen undescribed monoterpenoid indole alkaloids, voacafrines A-N, along with 7 known monoterpenoid indole alkaloids were isolated from the seeds of Voacanga africana Stapf. Among them, voacafrines A-G were aspidosperma-aspidosperma type bisindole alkaloids, while voacafrines H–N were aspidosperma-type monomers. Their structures and absolute configurations were elucidated by a combination of NMR, MS, and ECD analyses. Voacafrines A-C were characterized by an acetonyl moiety at C-5′, while voacafrine H possessed a methoxymethyl moiety at C-14 within aspidosperma-type alkaloids. The acetylcholinesterase (AChE) inhibitory activity and cytotoxicity of voacafrines A-N were evaluated. Voacafrines A-C and E-G were bisindole alkaloids that exhibited AChE inhibitory activity with IC50 values of 4.97–33.28 μM, while voacafrines I and J were monomers that showed cytotoxicity against several human cancer cell lines with IC50 values of 4.45–7.49 μM.

In continuation of our efforts to provide quantitative information on antiaddictive ibogan type alkaloid-producing Tabernaemontana species, we used gas chromatography-mass spectrometry (GC/MS) to compare the alkaloid profiles of the barks and/or leaves of one Mexican and one African species - T. arborea and T. crassa, respectively, with the primary sources of commercially available semisynthetic ibogaine, Voacanga africana root and stem bark. The qualitative and quantitative similarities between T. arborea and V. africana barks consolidate previous reports regarding the potential of the former as a promising alternative source of voacangine and ibogaine. The results also suggest that T. crassa could be used to produce conopharyngine and ibogaline, two compounds with the same basic skeletal structure and possibly similar antiaddictive properties as ibogaine.

Two new compounds, ( R )-4-(2-methylpentyl)-4 H -dithieno[2,3- b :3′,2′- e ]pyran ( 1 ) and 4-(2-ethylbutyl)-4 H -dithieno[2,3 -b :3′,2′ -e ]pyran ( 2 ) were extracted from the seeds of Voacanga africana . The molecular structures of these compounds were measured with the help of broad spectroscopic ( 1D and 2D-NMR , IR , ESI-TOF-MS , HR-MS ) analyses. The primary pharmacological operations of these compounds were brought to evaluation by applying the antibacterial extrasomatic test. The results revealed that compound 1 and 2 were in an effective position to stop the growth of Escherichia coli , Streptococcus and Salmonella typhi . On the other hand, the inhibitory impacts on Staphylococcus aureus as well as Pseudomonas aeruginosa were not apparent.

Herbal preparations from Voacanga africana are used in West and Central African folk medicine and are also becoming increasingly popular as a legal high in Europe. Recently, the main alkaloid voacangine was found to be a potent human ether-a-go-go-related gene channel blocker in vitro . Blockage of this channel might imply possible cardiotoxicity. Therefore, the aim of this study was to characterise voacangine in vivo to assess its pharmacokinetics and to estimate if further studies to investigate its cardiotoxic risk are required. Male Wistar rats received different doses of voacangine as a pure compound and as a hydro-ethanolic extract of V. africana root bark with a quantified amount of 9.71 % voacangine. For the obtained data, a simultaneous population pharmacokinetics model was successfully developed, comprising a two-compartment model for i. v. dosing and a one-compartmental model with two first-order absorption rates for oral dosing. The absolute bioavailability of voacangine was determined to be 11–13 %. Model analysis showed significant differences in the first absorption rate constant for voacangine administered as a pure compound and voacangine from the extract of V. africana . Taking into account the obtained low bioavailability of voacangine, its cardiotoxic risk might be neglectable in healthy consumers, but may have a serious impact in light of drug/drug interactions and impaired health conditions.

The jerantinine family of Aspidosperma indole alkaloids from Tabernaemontana corymbosa are potent microtubule-targeting agents with broad spectrum anticancer activity. The natural supply of these precious metabolites has been significantly disrupted due to the inclusion of T. corymbosa on the endangered list of threatened species by the International Union for Conservation of Nature. This report describes the asymmetric syntheses of (−)-jerantinines A and E from sustainably sourced (−)-tabersonine, using a straight-forward and robust biomimetic approach. Biological investigations of synthetic (−)-jerantinine A, along with molecular modelling and X-ray crystallography studies of the tubulin—(−)-jerantinine B acetate complex, advocate an anticancer mode of action of the jerantinines operating via microtubule disruption resulting from binding at the colchicine site. This work lays the foundation for accessing useful quantities of enantiomerically pure jerantinine alkaloids for future development.

One known bis-indole alkaloid-voacamine was isolated from

Voacafricines A and B, two unique monoterpenoid indole alkaloids each bearing five fused heterocycles, were obtained from the fruits of Voacanga africana. Their structures were elucidated by extensive spectroscopic methods and computational studies. A plausible biogenetic pathway was proposed from a common precursor, 19- epi-voacristine. Both compounds exhibited potent activity against Staphylococcus aureus and Salmonella typhi, and their activities were superior to those of the well-known antibacterial drugs berberine and fibrauretine.

Tabersonine, the main alkaloid in Voacanga seeds, was used as a lead compound to semi-synthesize tabersonine derivatives. In total, 13 compounds, containing 10 novel tabersonine derivatives, were synthesized by introducing substituent groups R1–R5. The acetylcholinesterase (AChE) inhibitory activities of tabersnonine derivatives were evaluated using Ellman’s method. Among them, compound (7) showed the highest AChE inhibitory activity with the IC50 value was 5.32 μM. The substituent groups R1–R5 showed different influences on the AChE inhibitory activities of tabersonine derivatives. The AChE inhibitory activities of tabersonine derivatives increased with the introduction of group R1 and/or combined groups R3, R4, while decreased with the introduction of group R5. And the group R2 showed no significant influence on the AChE inhibitory activities of tabersonine derivatives.

Voacangine (1) is an alkaloid found in the root bark of Voacanga africana. Our previous work has suggested that 1 is a novel transient receptor potential vanilloid type 1 (TRPV1) antagonist. In this study, the agonist and antagonist activities of 1 were examined against thermosensitive TRP channels. Channel activity was evaluated mainly using TRP channel-expressing HEK cells and calcium imaging. Herein, it was shown that 1 acts as an antagonist for TRPV1 and TRPM8 but as an agonist for TRPA1 (EC50, 8 μM). The compound competitively blocked capsaicin binding to TRPV1 (IC50, 50 μM). Voacangine (1) competitively inhibited the binding of menthol to TRPM8 (IC50, 9 μM), but it showed noncompetitive inhibition against icilin (IC50, 7 μM). Moreover, the compound selectively abrogated chemical agonist-induced TRPM8 activation and did not affect cold-induced activation. Among these effects, the TRPM8 inhibition profile is unique and noteworthy, because to date no studies have reported a menthol competitive inhibitor of TRPM8 derived from a natural source. Furthermore, this is the first report of a stimulus-selective TRPM8 antagonist. Accordingly, 1 may contribute to the development of a novel class of stimulus-selective TRPM8 blockers.

Herbal remedies have been employed for the treatment and management of various ailments since the beginning of human civilization. Voacanga is an extensive genus of the family Apocynaceae and consists of small trees inhabiting the tropical and subtropical regions of Africa. Voacanga plants have been used in the treatment of leprosy, diarrhea, and generalized edema, convulsions in children as well as to treat cases of orchitis, ectopic testes and gonorrhea.The aim of this review is to present as much information as was established from the available scientific literature. The present review comprises the ethnopharmacological, phytochemical and therapeutic potential of the plant genus Voacanga.The present review reports on 111 natural products as found in 44 references compiled from the major databases, viz., Chemical Abstracts, Science Direct, SciFinder, PubMed, Dr. Dukes Phytochemical and Ethnobotany, CIMER, and InteliHealth.An exhaustive survey of the literature revealed that indole alkaoids and steroids constitute the major classes of phytoconstituents of this genus. Pharmacological reports revealed that products derived from this genus have been used for the treatment of cancer, and for CNS, cardiotonic, antituberculosis, acetylcholinesterase (AChE), butyrylcholinesterase, antagonistic, anti-diarrheal activities.

Globospiramine (1), a new spirobisindole alkaloid possessing an Aspidosperma-Aspidosperma skeleton, together with deoxyvobtusine (2), deoxyvobtusine lactone (3), vobtusine lactone (4) and lupeol (5), were isolated and identified from Voacanga globosa through a bioassay-guided purification. The gross structure and absolute stereochemistry of 1 were established by circular dichroism spectroscopy, HR-MS and unambiguous NMR spectroscopic experiments. In addition, a new biogenetic pathway for the formation of the spiro-Aspidosperma-Aspidosperma skeleton is proposed. Alkaloid 1 showed potent antituberculosis activity against Mycobacterium tuberculosis H(37)Rv as evidenced in microplate Alamar blue assay (MIC = 4 μg/mL) and low-oxygen recovery assay (LORA (MIC = 5.2 μg/mL). The bisindole alkaloids also exhibited promising activity against acetylcholinesterase and, especially butyrylcholinesterase, with deoxyvobtusine (2) (IC(50) = 6.2 μM) as the most strongly inhibiting compound. This study extends the variety of alkaloid structural platforms which exhibit antimycobacterial and anticholinesterase activity.

A further study of Voacanga chalotiana Pierre ex Stapf has led to the isolation of two known indole alkaloids: polyneuridine [2] and akuammidine [3], and of two new oxygenated derivatives of voachalotine [1]: voachalotine oxindole [4] and 21(?)-hydroxyvoachalotine [5].

Voacarpine, a minor alkaloid obtained from Voacanga chalotiana Pierre ex Stapf (Apocynaceae), is shown to have the tautomeric structure VII ⇆ VIII. The non basic O,N‐diacetyl‐ and O,N‐ditosyl derivatives are true 2‐acyl‐indoles (IX, X). Isovoacarpine, isomeric with voacarpine, is obtained by acid treatment followed by neutralization; it is also a carbinolamine compound. On acetylation, it gives a monoacetyl derivative. UV, IR, NMR and mass spectra of voacarpine and derivatives are discussed. Copyright © 1965 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim

Voachalotine, the major alkaloid of Voacanga Chalotiana (Pierre ex Stapf), has been shown to have structure (A). Copyright © 1961 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim

New drugs are needed to help overcome the increasing problem of drug resistance in parasites that cause diseases such as malaria and trypanosomiasis. In this study, alkaloid compounds isolated from extracts of the plants Flindersia amboinensis, Stephania zippeliana and Voacanga papuana from Papua New Guinea and Flindersia acuminata from Australia were examined for their antiparasitic activity against Plasmodium falciparum strains and Trypanosoma brucei brucei as well as their cytotoxicity against the mammalian cell lines HEK 293 and HeLa. The most active compound, dimethylisoborreverine (DMIB), showed submicromolar activity, with 50% inhibitory concentration (IC(50)) values between 20 nM and 810 nM both against drug-sensitive and drug-resistant P. falciparum strains, along with moderate selectivity against T. b. brucei and mammalian cells. Stage specificity studies revealed that P. falciparum trophozoite-stage parasites were more susceptible to DMIB than ring- or schizont-stage parasites. DMIB-treated trophozoites showed changes in food vacuole morphology, with an apparent reduction in haemozoin formation that does not appear to be inhibited via the direct binding of haem. These findings suggest a potential for indole alkaloids from Flindersia spp. as new antiparasitic agents.

Voacanga africana (Apocynaceae) is a small tropical African tree. The root bark and seeds of this tree contain a number of alkaloids, including ibogaine (a hallucinogenic/aphrodisiac compound in bark), tabersonine (a major constituteent of seeds) and other voacanga alkaloids, traditionally used in Africa for religious purposes. Recently, some kinds of products containing this plant (root bark and seeds) have been distributed in the drug market in expectation of its hallucinogenic/aphrodisiac effects. There has been no report that has discussed quantitative analyses of these alkaloids in the products and their botanical origins. In this study, to investigate the trend of such a non-controlled psychotropic plant of abuse, a simultaneous analytical method was developed using LC/MS for the voacanga alkaloids including ibogaine and tabersonine in the commercial products of V. africana. Moreover, the botanical origins of these products were investigated by DNA analyses. As a result of the LC/MS analyses, the products were classified into two chemical types; an ibogaine-type and a tabersonine-type. The samples of the ibogaine-type contain ibogaine (0.05-0.6%) and other voacanga alkaloids; voacamine, voacamidine and voacangine, while those of the tabersonine-type mainly contain tabersonine (0.6-1.6%). The sequence analyses of chloroplast DNA, trnL-F region suggested that most of the products were derived from V. africana or closely related plants. They were classified into four genotypes based on nucleotide sequence of the trnL-F IGS region. The proposed methods of chemical and DNA analyses would be useful for investigating the trend in the distribution of the products of V. africana.

In this study, essential oils from Voacanga africana seeds at different extraction stages were investigated. In the chemical composition analysis, 27 compounds representing 86.69-95.03% of the total essential oils were identified and quantified. The main constituents in essential oils were terpenoids, alcohols and fatty acids accounting for 15.03-24.36%, 21.57-34.43% and 33.06-57.37%, respectively. Moreover, the analysis also revealed that essential oils from different extraction stages possessed different chemical compositions. In the antioxidant evaluation, all analysed oils showed similar antioxidant behaviours, and the concentrations of essential oils providing 50% inhibition of DPPH-scavenging activity (IC50) were about 25 mg/mL. In the antimicrobial experiments, essential oils from different extraction stages exhibited different antimicrobial activities. The antimicrobial activity of oils was affected by extraction stages. By controlling extraction stages, it is promising to obtain essential oils with desired antimicrobial activities.

A new monoterpenoid indole alkaloid compound (1) and six known monoterpenoid indole alkaloids compounds (2–7) were isolated from the barks of Voacanga africana Staph. The structures were established by spectral analysis as ibogamine-16-carboxylic acid,17,20-didehydro-5,6-dioxo-10-methoxy-methyl ester (1), voacamine (2), vobasine (3), voacangine (4), voacristine (5), 19-epi-voacristine (6) and 19-epi-heyneanine (7). Compound 1 was confirmed by X-ray crystallographic analysis. All of the isolated compounds were evaluated for cytotoxicity against five cell lines (HEPG-2, A375, MDA-MB-231, SH-SY5Y, CT26). Among them, compounds 2 and 6 displayed significant inhibitory activities, compounds 3, 4 and 5 showed moderate inhibitory activities, while compounds 1 and 7 showed no inhibitory activities against the five cell lines.

Three indole alkaloids, voacamine (1), 3,6-oxidovoacangine (2), and a new alkaloid, 5-hydroxy-3,6-oxidovoacangine (3), isolated from Voacanga africana were found to exhibit potent cannabinoid CB1 receptor antagonistic activity. This is the first example of CB1 antagonists derived from natural alkaloids.

Voacanga globosa (Blanco), a plant endemic to the Philippines, is traditionally used especially by indigenous people of Bataan in the treatment of ulcers, wounds and tumorous growths. This study aimed to provide scientific evidence to therapeutic properties by determining cytotoxic and pro-apoptotic activity of HPLC fractions from leaves on HCT116 human colon carcinoma and A549 human lung carcinoma cell lines. Ethanolic extraction was performed on V globosa leaves followed by hexane and ethyl acetate partitioning. Silica gel column chromatography and high performance liquid chromatography (HPLC) produced MP1, MP2 and MP3 fractions. Cytotoxic activity of the fractions was determined through MTT assay against the cancer cell lines HCT116 and A549 and the non-cancer AA8 Chinese hamster ovarian cell line. Pro-apoptotic activities of the most active fractions were further assessed through DAPI staining, TUNEL assay and JC-1 mitochondrial membrane potential assay with HCT116 cells. While the MP1 fraction exerted no significant activity against all cell lines tested, MP2 and MP3 fractions demonstrated high toxicity against HCT116 and A549 cells. The MP3 fraction induced formation of apoptotic bodies, condensed DNA and other morphological changes consistent with apoptosis of HCT116 cells and TUNEL assay showed significant increase in DNA fragmentation over time. In these cells, the MP3 fraction also induced mitochondrial membrane destabilization, which is generally associated with the beginning of apoptosis. Phytochemical analysis demonstrated the presence only of saponins and terpenoids in the MP3 fraction. The results indicate that the MP3 fraction exerts cytotoxic activity on HCT116 cells via induction of apoptosis triggered by loss of mitochondrial membrane potential crucial for cell survival.

To study the alkaloids of Voacanga africana.The alkaloids were isolated by normal phase silica gel and Sephadex LH-20 column chromatography. Their structures were elucidated by analysis of spectroscopic data.Eight alkaloids were isolated and their structures were elucidated as voacangine(1), voacangine hydroxyindolenine(2), 19R-epi-voacristine(3), epi-ibogaine(4), vobasine(5), 19-epi-heyneanine(6), vobtusine(7) and voacamine(8).Compounds 2-4 and 6 are isolated from this plant for the first time.

The optically active Na-methyl, Nb-benzyltetracyclic ketone 1 was converted into either diastereomeric spirocyclic oxindole 2a (91:9) or 2b (97:3) with high diastereoselectivity on prudent choice of osmium reagents. Oxindole 2a is now available in enantiospecific form for the synthesis of Alstonia alkaloids while diastereomer 2b can be employed for the preparation of Gardneria and Voacanga bases.

The optically active Na-methyl, Nb-benzyltetracyclic ketone 1 was converted into either diastereomeric spirocyclic oxindole 2a (91:9) or 2b (97:3) with high diastereoselectivity on prudent choice of osmium reagents. Oxindole 2a is now available in enantiospecific form for the synthesis of Alstonia alkaloids while diastereomer 2b can be employed for the preparation of Gardneria and Voacanga bases.

A convenient method has been developed to convert NaH tetracyclicketone 1a into the two corresponding oxindoles[C(7)] diastereospecifically. Treatment of the NaH, Nb-benzyl tetracyclicketone 1a with t-BuOCl provided diastereomer 2a (related to Voacanga oxindoles), whereas the same process with NbH (1b) or Nb-benzoyl (1c) substituted analogs funished the diastereomers 2b and 2c (related to alstonisine), respectively.

This review examines the natural products in Voacanga africana, a small tree, whose seeds are the most economically important plant part though in traditional medicines the bark and root are also widely used. Voacanga is used to treat or cure a wide range of diseases in Africa. This paper also discusses the botany, chemistry and pharmacological properties and presents current and potential applications of this species. The alkaloids are the principal bioactive compounds responsible for its use in traditional medicine. The major alkaloids include voacamine, voacangine, vobasine, and ibogaime. Others include voacristine, voacamidine, voacarine, voaphylline, vobtusine, voalfolidine and tabersonine. With over 1,600 tons of seeds exported annually from Ghana and Cote D'Ivoire, voacanga is an important source of additional income for harvesters and exporters in West Africa.

Aqueous extracts of six plant species used in Cameroonian ethnomedicine for the relief of stomach complaints were tested for antiulcer activity. An HCl/EtOH solution was used to induce gastric lesions in male Wistar rats (140–190 g). The extracts of Voacanga africana, Eremomastax speciosa, Emilia praetermissa, Spilanthes filicaulis and Centella asiatica produced complete mucosal cytoprotection at a dose of 1000, 190, 500, 2000 and 500 mg/kg respectively. The extract of Clerodendrum splendens (500, 750, 1000 mg/kg) showed significant (p

This paper provides a short overview of ritual African hallucinogens. In addition to examples already listed by Schultes and Hofmann in their classic text books, Boophane disticha, Alchornea floribunda, Monadenium lugardae, Mostuea spp. and Voacanga bracteata are identified as African botanicals with proven or alleged hallucinogenic potential.

A new, weakly antibacterial indole alkaloid, named lombine, together with the known alkaloid voacangine, have been isolated from the bark of Voacanga foetida (Bl.) Rolfe (Apocynaceae), a plant used on Lombok, Indonesia, for medicinal purposes. A combined chemo- and bio-rational strategy was developed to target this plant for investigation. Lombine was shown to be bactericidal against Staphylococcus aureus and Escherichia coli.

Conopharyngine, the major alkaloid present in the leaves of Tabernaemontana (Conopharyngia) pachysiphon var. cumminsi (Stapf) H. Huber was isolated and identified by Thomas & Starmer (1963). The same alkaloid has also been found in the stem bark of a Nigerian variety of the same species by Patel & Poisson (1966) and in the stem bark of Conopharyngia durissima by Renner, Prins & Stoll (1959). Conopharyngine is an indole alkaloid of the voacanga type, being 18-carbomethoxy-12,13dimethoxyibogamine (Fig. 1) and is thus closely related to voacangine and coronaridine.

SummaryCardiotonic drugs are classified in two groups : 1) heterosides, and 2) alca-loids.The heterosides include cardenolides and scilladienolides. The chemical structure of each drug is shown as well as the relations between the various compounds presented.The alcaloids include 1) substances with phenanthrene nucleus extracted from Erythrophleums, 2) indolic alcaloids isolated from Voacanga. These alcaloids are still in the experimental stage of pharmacological investigation.

ObjectiveTo determine the antibacterial, antifungal, antiprotozoal, cytotoxic, and phytochemical properties of ethanol extracts of leaves of Voacanga globosa (Blanco) Merr. (V. globosa).MethodsThe extracts were tested against bacteria and fungus through disc diffusion assay; against protozoa through growth curve determination, antiprotozoal and cytotoxicity assays.ResultsThe extract revealed antibacterial activities, inhibiting the growth of Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa, Micrococcus luteus, and Salmonella typhimurium. Antifungal assay showed that it inhibited Candida albicans. The antiprotozoal assay against Trichomonas vaginalis and Entamoeba histolytica showed that V. globosa can inhibit the parasites, wherein the action can be comparable to metronidazole. With the in situ cell death detection kit, Trichomonas vaginalis and Entamoeba histolytica exposed to V. globosa leaf extract was observed to fluoresce simultaneously in red and yellow signals signifying apoptotic-like changes. Preliminary phytochemical screening revealed the chemical composition of plant extract containing alkaloids, saponins, 2-deoxysugars, and hydrolysable tannins.ConclusionsThus, this study provides scientific evidence on the traditional use of V. globosa leaf extract in treating microbial diseases. Further, the leaf extract can possibly be used to produce alternative forms of antimicrobials.

The family of the Apocynaceae is usually subdivided into two subfamilies, the Plumerioideae with the type genus Plumeria from tropical America, and the Apocynoideae, often named Echitoideae, with the type genus Apocynum from North America. These subfamilies show two characters which are more or less diagnostic for all members. However, since the taxonomists have built up the present scheme of the Apocynaceae, phytochemists have observed that many plants belonging to the Plumerioideae contain alkaloids, and that many representatives of the Apocynoideae contain glycosides. Some of the alkaloids, e.g. those of Catharanthus, Rauvolfia and Voacanga , and some of the glycosides, e.g. those of Funtumia and Strophanthus are of medicinal interest. In the present paper, the arrangement of the genera within the Plumerioideae is mainly that of Pichon (1949, 1950, 1953a, 1953b). He subdivided all tribes, except the Tabernaemontaneae, into subtribes, which is an excellent concept according to the present author. The latter, however, does not always agree with the delimitation of the genera. For instance, he does not accept the sinking of Acokanthera under Carissa , especially as the plants belonging to these genera show great differences in architecture (Halle & Oldeman 1970; Halle, Oldeman & Tomlinson, 1978), but he sinks several genera maintained by Pichon, e.g. Ervatamia under Tabernaemontana (1976).

The structure of 3-hydroxyvoachalotine, a new indole alkaloid isolated from the root bark of Voacanga chalotiana , has been determined by spectroscopic analysis and by chemical correlation with voachalotine.