Tabernaemontana Elegans Research Articles

Determination of <i>in vitro</i> hepatotoxicity of two plants of the Apocynaceae family

Determination of in vitro hepatotoxicity of two plants of the Apocynaceae family Although toxicity has been ascribed to Acokanthera oppositifolia and Tabernaemontana elegans, no data exists concerning its potential hepatotoxic effects. Using a multi-parametric assay it was observed that hot water and methanol extracts of A. oppositifolia and T. elegans decreased cell viability, destabilized the mitochondrial membrane and induced strong apoptotic signals.

In vitro antiplasmodial screening of ethnopharmacologically selected South African plant species used for the treatment of malaria

Ethnopharmacological relevancePlant species used by Venda people of South Africa in the treatment of malaria and associated symptoms were evaluated for their antiplasmodial efficacy as well as cytotoxic properties and some showed significant activity. Materials and methodsIn vitro antiplasmodial activity and cytotoxic properties were evaluated on 20 indigenous plant species. Ground plant material was extracted in dichloromethane: 50% methanol (1:1). Antiplasmodial activity was evaluated against the chloroquine-sensitive strain of Plasmodium falciparum (NF54). The cytotoxicity of the plant extracts were assessed against mammalian L-6 rat skeletal myoblast cells and the selectivity index (SI) calculated. ResultsOf the 43 plant extracts evaluated, 10 exhibited pronounced antiplasmodial activity (IC50≤5μg/ml) with good therapeutic indices (SI≥10). Lipophilic plant extracts were relatively more potent than polar extracts. Tabernaemontana elegans Stapf. (Apocynaceae) and Vangueria infausta Burch. subsp. infausta (Rubiaceae) extracts displayed significant antiplasmodial activity (IC50<2μg/ml). ConclusionFindings of this study partly support the ethnomedical use of the investigated plant species by Venda people as antimalarial remedies. The study also highlights some of the knowledge gaps that require further phytochemical studies on the specified plant species.

Monoterpene bisindole alkaloids, from the African medicinal plant Tabernaemontana elegans, induce apoptosis in HCT116 human colon carcinoma cells

Ethnopharmacological relevanceTabernaemontana elegans is a medicinal plant used in African traditional medicine to treat several ailments including cancer. The aims of the present study were to identify anti-cancer compounds, namely apoptosis inducers, from Tabernaemontana elegans, and hence to validate its usage in traditional medicine. Methods and materialsSix alkaloids, including four monomeric indole (1–3, and 6) and two bisindole (4 and 5) alkaloids, were isolated from the methanolic extract of Tabernaemontana elegans roots. The structures of these compounds were characterized by 1D and 2D NMR spectroscopic and mass spectrometric data. Compounds 1−6 along with compound 7, previously isolated from the leaves of the same species, were evaluated for in vitro cytotoxicity against HCT116 human colon carcinoma cells by the MTS metabolism assay. The cytotoxicity of the most promising compounds was corroborated by Guava-ViaCount flow cytometry assays. Selected compounds were next studied for apoptosis induction activity in HCT116 cells, by evaluation of nuclear morphology following Hoechst staining, and by caspase-3 like activity assays. ResultsAmong the tested compounds (1−7), the bisindole alkaloids tabernaelegantine C (4) and tabernaelegantinine B (5) were found to be cytotoxic to HCT116 cells at 20µM, with compound 5 being more cytotoxic than the positive control 5-Fluorouracil (5-FU), at a similar dose. In fact, even at 0.5µM, compound 5 was more potent than 5-FU. Compounds 4 and 5 induced characteristic patterns of apoptosis in HCT116 cancer cells including, cell shrinkage, condensation, fragmentation of the nucleus, blebbing of the plasma membrane and chromatin condensation. Further, general caspase-3-like activity was increased in cells exposed to compounds 4 and 5, corroborating the nuclear morphology evaluation assays. ConclusionsBisindole alkaloids tabernaelegantine C (4) and tabernaelegantinine B (5) were characterized as potent apoptosis inducers in HCT116 human colon carcinoma cells and as possible lead/scaffolds for the development of anti-cancer drugs. This study substantiates the usage of Tabernaemontana elegans in traditional medicine to treat cancer.

Effect of an alkaloidal fraction of Tabernaemontana elegans (Stapf.) on selected micro-organisms

Ethnopharmacological relevanceBacterial infections remain a significant threat to human health. Due to the emergence of widespread antibiotic resistance, development of novel antibiotics is required in order to ensure that effective treatment remains available. There are several reports on the ethnomedical use of Tabernaemontana elegans pertaining to antibacterial activity. Aim of the studyThe aim of this study was to isolate and identify the fraction responsible for the antimicrobial activity in Tabernaemontana elegans (Stapf.) root extracts. Materials and methodsThe active fraction was characterized by thin layer chromatography (TLC) and gas chromatography–mass spectrometry (GC–MS). Antibacterial activity was determined using the broth micro-dilution assay and antimycobacterial activity using the BACTEC radiometric assay. Cytotoxicity of the crude extract and fractions was assessed against primary cell cultures; lymphocytes and fibroblasts; as well as a hepatocarcinoma (HepG2) and macrophage (THP-1) cell line using the Neutral Red uptake and MTT assays. ResultsThe crude root extracts were found to contain a high concentration of alkaloids (1.2%, w/w). GC–MS analysis identified the indole alkaloids, voacangine and dregamine, as major components. Antibacterial activity was limited to the Gram-positive bacteria and Mycobacterium species, with MIC values in the range of 64–256μg/ml. When combined with antibiotics, additive antibacterial effects were observed. Marked cytotoxicity to all cell lines tested was evident in the MTT and Neutral Red uptake assays, with IC50 values <9.81μg/ml. ConclusionsThis study confirms the antibacterial activity of Tabernaemontana elegans and supports its potential for being investigated further for the development of a novel antibacterial compound.

Phytochemical characterization of antimycobacterial crude extracts from medicinal plants traditionally used in Mozambique

A number of medicinal plants have long been used by traditional healers to treat tuberculosis and related diseases in Mozambique [1,2]. The present study was aimed to evaluate selected medicinal plants for their in vitro antimycobacterial activity, and reveal the main classes of compounds which might account for the observed activity. Four organic solvents (n-hexane, dichloromethane, ethylacetate, and 70% ethanol) were used for the sequential extraction. Decoction of each plant material was prepared according to traditional use. Different species of mycobacteria, namely, M. smegmatis, M. bovis BCG, M. avium, and M. tuberculosis were employed to screen extracts by broth microdilution method. The cytotoxicity against human macrophages from the monocytic THP-1 cells was also evaluated. Overall, n-hexane extracts of Maerua edulis Gilg & Gilg-Ben. and Securidaca longepedunculata Fresen, ethyl acetate extract of Tabernaemontana elegans Stapf and dichloromethane extract of Zanthoxylum capense (Thunb.) Harv. were found to possess considerable activity against M. bovis BCG and M. tuberculosis H37Ra with MIC=15.6–62.5µg/mL. Tabernaemontana elegans ethyl acetate extract displayed strong activity against M. tuberculosis H37Rv (MIC 15.6µg/mL) as well as potent cytotoxic effects in THP-1 cells (IC50 <4µg/mL). Based on 1H NMR spectroscopic analysis, major components in both Maerua edulis and Securidaca longepedunculata n-hexane extracts were linear chain unsaturated fatty acids. Zanthoxylum capense dichloromethane extract contained more complex constituents (mostly phenolic compounds), and the prominent compounds in ethyl acetate extract of Tabernaemontana elegans were identified as indole alkaloids.

Antimycobacterial evaluation and preliminary phytochemical investigation of selected medicinal plants traditionally used in Mozambique

Several medicinal plants are traditionally used in Mozambique to treat tuberculosis and related symptoms. It was aimed to assess the in vitro antimycobacterial activity of crude extracts from fifteen medicinal plants and to reveal main classes of compounds which may account for the activity of extracts. The plant materials were sequentially extracted by n-hexane, dichloromethane, ethyl acetate, and 70% ethanol. Decoction of each plant material was also prepared according to traditional use. Broth microdilution method was employed to screen extracts against two mycobacterial species: Mycobacterium smegmatis ATCC 607 and Mycobacterium tuberculosis H37Rv. The extracts with minimum inhibitory concentration(s) (MIC) below 125 μg/mL were considered active and further tested against different mycobacterial species and strains, namely Mycobacterium tuberculosis H37Ra, Mycobacterium bovis BCG ATCC 35734, Mycobacterium smegmatis mc(2) 155, Mycobacterium avium DSM 44156 and DSM 44157. Cytotoxic effect was evaluated against human macrophages from the monocytic THP-1 cells. Main classes of compounds in these active extracts were proposed from their (1)H NMR spectroscopic characterizations. n-Hexane extracts of Maerua edulis and Securidaca longepedunculata, ethyl acetate extract of Tabernaemontana elegans and dichloromethane extract of Zanthoxylum capense were found to possess considerable activity against Mycobacterium bovis BCG and Mycobacterium tuberculosis H37Ra with MIC 15.6-62.5 μg/mL. Tabernaemontana elegans ethyl acetate extract displayed strong activity against Mycobacterium tuberculosis H37Rv (MIC 15.6 μg/mL). Except for Tabernaemontana elegans ethyl acetate extract which presented potent cytotoxic effects in THP-1 cells (IC(50)<4 μg/mL), the other three plant extracts showed moderate to none toxicity. Based on (1)H NMR spectroscopic analysis, major components in both Maerua edulis and Securidaca longepedunculata n-hexane extracts were linear chain unsaturated fatty acids. Zanthoxylum capense dichloromethane extract contained more complex constituents (mostly phenolic compounds). In the most potent extract, Tabernaemontana elegans ethyl acetate extract, the prominent compounds were identified as indole alkaloids. The pronounced antimycobacterial activity of the medicinal plants Maerua edulis, Securidaca longepedunculata, Zanthoxylum capense, and Tabernaemontana elegans suggested that they might provide compounds which could be potential anti-TB drug leads.

Alasmontamine A, A First Tetrakis Monoterpene Indole Alkaloid from Tabernaemontana elegans

A novel tetrakis monoterpene indole alkaloid, alasmontamine A (1) consisting of bis-vobtusine-type skeletons, was isolated from the leaves of Tabernaemontana elegans. The structure including the relative stereochemistry was elucidated on the basis of spectroscopic data. Alasmontamine A (1) exhibited moderate cell growth inhibitory activity against HL-60 cells.

ChemInform Abstract: Induction of Apoptosis in HuH‐7 Cancer Cells by Monoterpene and β‐Carboline Indole Alkaloids Isolated from the Leaves of Tabernaemontana elegans.

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Novel β-carboline indole alkaloids from the leaves of Tabernaemontana elegans

Novel β-carboline indole alkaloids from the leaves of Tabernaemontana elegans

Monoterpene indole alkaloids from the leaves of Tabernaemontana elegans induce apoptosis activity in human hepatoma cells

Monoterpene indole alkaloids from the leaves of Tabernaemontana elegans induce apoptosis activity in human hepatoma cells

Induction of apoptosis in HuH-7 cancer cells by monoterpene and β-carboline indole alkaloids isolated from the leaves of Tabernaemontana elegans

Three known (1–3) and a novel (4) monoterpene indole alkaloids have been isolated from the methanol extract of leaves of Tabernaemontana elegans and their structures were elucidated by a series of spectroscopic experiments, involving NMR, MS, UV, and IR techniques. The isolated monoterpene indole alkaloids along with previously described β-carbolines (5–7) from the same specimen were studied for their apoptosis induction activity in human hepatoma HuH-7 cells. Methodology for apoptosis induction studies included cell viability assays, nuclear morphology assessments, and general caspase-3-like activity assays. The monoterpene indole alkaloids, tabernaemontanine (1) and vobasine (3) showed the most promising apoptosis induction profile in HuH-7 cells.

Tabernines A−C, β-Carbolines from the Leaves of Tabernaemontana elegans

Three novel beta-carboline indole alkaloids (1-3) have been isolated from a MeOH extract of the leaves of Tabernaemontana elegans. The structures were established by means of spectroscopic techniques including 2D NMR experiments. Compounds 1 and 2 contain a two-carbon unit, attached to a structurally related beta-carboline skeleton, as part of an additional six-membered ring in 1 and a seven-membered ring in 2. To the best of our knowledge, this is the first report of beta-carboline indole alkaloids from the genus Tabernaemontana. Compounds 1-3 were evaluated for their ability to modulate multidrug resistance in mouse lymphoma cell lines. Compounds 1 and 3 exhibited a weak activity.

IN VITRO BIOACTIVITY OF VENDA MEDICINAL PLANTS USED IN THE TREATMENT OF RESPIRATORY CONDITIONS

Infectious diseases, especially those affecting the respiratory tract, represent a critical problem to health. Crude methanol and water extracts of ten Venda plants reported to be used ethnomedically in the treatment of respiratory conditions were assessed for their antimicrobial activity against standard strains and clinical isolates of Candida albicans, Haemophilis influenza, Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae and Mycobacterium smegmatis using the disc diffusion assay. Four of the ten plants tested demonstrated antimicrobial activity. No extracts showed activity against K. pneumoniae. Minimum inhibitory concentrations (MIC), as determined by the broth microdilution assay, showed three plants, Securidaca longepedunculata, Syzygium cordatum and Tabernaemontana elegans, to possess MICs ≤ 1mg/mL. These extracts, however showed toxicity in vitro to lymphocytes. The crude extracts were tested for antioxidant activity using the TEAC assay, but only S. cordatum showed significant antioxidant activity. Phytochemical screening, performed by thin layer chromatography (TLC) using a variety of mobile phases and selective visualization reagents demonstrated various classes of compounds in the active extracts. While three plant species were identified with significant antimicrobial activity, there remains a need for identification of the bioactive constituents, as well as a further investigation of their toxicity. Acknowledgements: NRF provided funding

In-vitro bioactivity of Venda medicinal plants used in the treatment of respiratory conditions

Infectious diseases, especially those affecting the respiratory tract, represent a critical problem to health. Crude methanol and water extracts of 10 Venda plants reported to be used ethnomedically in the treatment of respiratory conditions were assessed for their antimicrobial activity against standard strains and clinical isolates of Candida albicans, Haemophilis influenzae, Klebsiella pneumoniae, Staphylococcus aureus, Streptococcus pneumoniae, and Mycobacterium smegmatis using the disc diffusion assay. Four of the 10 plants tested possessed antimicrobial activity, but no activity against K. pneumoniae was observed. Minimum inhibitory concentrations, as determined by the broth microdilution assay, showed three plants, Securidaca longepedunculata, Syzygium cordatum, and Tabernaemontana elegans, to possess MICs </= 1 mg/mL. Phytochemical screening, performed by separation on thin layer chromatography using a variety of mobile phases and visualization with spray reagents as well as UV light showed various classes of compounds in the active extracts. Some of these have been associated with antioxidant activity, as confirmed in this study. Moreover, these extracts showed toxicity in vitro to lymphocytes. Although three plant species with significant antimicrobial activity were identified, there is a need for further scientific evaluation regarding identification of the bioactive constituents, as well as their toxicity.

Indole alkaloids from a traditional medicinal plant: Tabernaemontana elegans Staph

Indole alkaloids from a traditional medicinal plant: Tabernaemontana elegans Staph

Screening of Venda medicinal plants for antifungal activity against Candida albicans

Crude methanol and water extracts of 32 plant species, used for the treatment of infectious diseases in Venda, were screened for in vitro activity against Candida albicans standard strain (ATCC 10231) and five clinical isolates. Water extracts of 16 plant species and methanol extracts of 11 plant species inhibited candidiasis growth. Inhibition at <1 mg/ml, against the C. albicans strains tested, was observed for the methanol extracts of Combretum molle (root), Piper capense (bark), Solanum aculeastrum (fruits), Syzygium cordatum (bark) and Zanthoxylum davyi (bark) as well as the aqueous bark extract of Afzelia quanzensis and root extract of Tabernaemontana elegans. These results implicate that the extracts contain compounds with therapeutic potential against C. albicans.

Alkaloid formation in cell suspension cultures of Tabernaemontana elegans after feeding of tryptamine and loganin or secologanin

A cell suspension culture of Tabernaemontana elegans lost its ability to produce alkaloids after a prolonged period of subculture. To determine whether it was still capable of performing the later steps of the alkaloid biosynthetic pathway, the culture was fed with tryptamine and loganin. The precursors and alkaloids were determined in the biomass and in the medium during a growth cycle. In this culture, an increase in the amount of serotonin was found in the biomass after feeding of tryptamine and loganin. Secologanin was detected in small amounts but strictosidine was not. Therefore, a limitation in alkaloid formation in this T. elegans cell line occured in the formation of secologanin from loganin. After feeding of secologanin alone, strictosidine, 10-hydroxy strictosidine, strictosidinic acid and two other indole alkaloids, as yet unidentified, were formed. However, the alkaloids originally produced by this cell line were not found. As the biosynthesis is impaired at several steps, it seems that the loss of productivity is more likely to be to a change on the level of the regulation of the pathway, than due to the loss of the capacity to express an individual biosynthetic gene of the pathway.

Characterization of a Suspension Culture ofTabernaemontana eleganson Growth, Nutrient Uptake, and Accumulation of Indole Alkaloids*

A suspension culture of TABERNAEMONTANA ELEGANS was characterized on growth, nutrient uptake (carbohydrate, nitrogen, and phosphate), and on accumulation of indole alkaloids. Besides tryptamine seven indole alkaloids were isolated and identified: vobasine, vobasinol, perivine, isositsirikine, apparicine, tubotaiwine, and O-acetylvallesamine. In spite of the presence of vobasinol as major product, only trace amounts of dimeric indole alkaloids could be detected. Alkaloid formation started at the early stationary phase.

Indole Alkaloids fromTabernaemontana elegans1

The isolation of 18 indole alkaloids from a whole plant extract of TABERNAEMONTANA ELEGANS is described. Five new and 13 known alkaloids were isolated and identified. The five new alkaloids are tabernaemontaninol, dregaminol, dregaminol-methylether, 3- R/S-hydroxy-tabernaelegantine B and 3-methoxy-tabernaelegantine C. The other alkaloids are apparicine, 16- S-hydroxy-16, 22-dihydro-apparicine, tubotaiwine, vobasine, vobasinol, dregamine, tabernaemontanine, iso-voacangine, 3- R/S-hydroxy-conodurine, tabernaelegantine A, B, C and D.

Indole alkaloids from a callus culture of Tabernaemontana elegans

Fourteen indole alkaloids have been isolated from a callus culture of Tabernaemontana elegans. One of them is new, 3-oxo-isovoacangine, the others are the known isovoacangine, 3-R/S-hydroxy-isovoacangine, 3-R/S-hydroxy-coronaridine, isositsirikine, geissoschizol, tabernaemontanine, vobasine, vobasinol, apparicine, 16-hydroxy-16,22-dihydro-apparicine, tubotaiwine, 3-R/S-hydroxy-conodurine and monogagaine. The alkaloid content is similar to that of the whole plant, except for the absence ofthe tabernaelegantines, which were major components in the plant extract.