Indole Alkaloids of Rauvolfia ligustrina and Their Anxiolytic Effects in Adult Zebrafish.

Rauvolfia species are well known as producers of bioactive monoterpene indole alkaloids, which exhibit a broad spectrum of biological activities. A new vobasine-sarpagan-type bisindole alkaloid (1: ) along with six known monomeric indoles (2, 3/4, 5: , and 6/7: ) were isolated from the ethanol extract of the roots of Rauvolfia ligustrina. The structure of the new compound was elucidated by interpretation of their spectroscopic data (1D and 2D NMR and HRESIMS) and comparison with published data for analog compounds. The cytotoxicity of the isolated compounds was screened in a zebrafish (Danio rerio) model. The possible GABAergic (diazepam as the positive control) and serotoninergic (fluoxetine as the positive control) mechanisms of action in adult zebrafish were also evaluated. No compounds were cytotoxic. Compound 2: and the epimers 3: /4: and 6: /7: showed a mechanism action by GABAA, while compound 1: showed a mechanism action by a serotonin receptor (anxiolytic activity). Molecular docking studies showed that compounds 2: and 5: have a greater affinity by the GABAA receptor when compared with diazepam, whereas 1: showed the best affinity for the 5HT2AR channel when compared to risperidone.

Extracts of the Medicinal Plants Pao Pereira and Rauwolfia vomitoria Inhibit Ovarian Cancer Stem Cells In Vitro.

Ovarian cancer has an enrichment of cancer stem cells (CSCs) which contribute to the treatment resistant tumor's high rate of recurrence and metastasis. Here we investigated 2 plant extracts from the medicinal plants Pao Pereira (Pao) and Rauwolfia vomitoria (Rau) each for their activities against ovarian CSCs. Both Pao and Rau inhibited overall proliferation of human ovarian cancer cell lines with IC50 ranging from 210 to 420 µg/mL and had limited cytotoxicity to normal epithelial cells. Ovarian CSC population was examined using cell surface markers and tumor spheroid formation assays. The results showed that both Pao and Rau treatment significantly reduced the ovarian CSC population. Pao and Rau had similar activities in inhibiting ovarian CSCs, with IC50s of ~120 µg/mL for 24 hours treatment, and ~50 µg/mL for long-term tumor spheroid formation. Nuclear ß-catenin levels were decreased, suggesting suppression of Wnt/ß-catenin signaling pathway. Taken together, data here showed that Pao and Rau both inhibited ovarian cancer stem cells, probably in preference to the bulk of tumor cells. Further mechanistic studies and in vivo investigation validating these findings are warranted, given that inhibition of cancer stem cells holds the promise of comprehensively inhibiting cancer metastasis, drug resistance and recurrence.

Anti-seizure activity of African medicinal plants: The identification of bioactive alkaloids from the stem bark of Rauvolfia caffra using an in vivo zebrafish model.

ETHNOPHARMACOLOGICAL RELEVANCE: Epilepsy is one of the major chronic diseases that does not have a cure to date. Adverse drug reactions have been reported from the use of available anti-epileptic drugs (AEDs) which are also effective in only two-thirds of the patients. Accordingly, the identification of scaffolds with promising anti-seizure activity remains an important first step towards the development of new anti-epileptic therapies, with improved efficacy and reduced adverse effects. Herbal medicines are widely used in developing countries, including in the treatment of epilepsy but with little scientific evidence to validate this use. In the search for new epilepsy treatment options, the zebrafish has emerged as a chemoconvulsant-based model for epilepsy, mainly because of the many advantages that zebrafish larvae offer making them highly suitable for high-throughput drug screening. AIM OF THE STUDY: In this study, 20 medicinal plants traditionally used in South Africa to treat epilepsy were screened for anti-epileptic activity using a zebrafish larvae model. MATERIALS AND METHODS: Toxicity triaging was conducted on 120 crude extracts, 44 fractions and three isolated compounds to determine the maximum tolerated concentration (MTC) of each extract, fraction or compound. MTC values were used to guide the concentration range selection in bioactivity studies. The effectiveness of crude extracts, fractions and isolated compounds from Rauvolfia caffra Sond. in suppression of pentylenetetrazole (PTZ) induced seizure-like behaviour in a 6-dpf zebrafish larvae model was measured using the PTZ assay. RESULTS: Following a preliminary toxicity triage and bioactivity screen of crude extracts from 20 African plants used traditionally for the treatment and management of epilepsy, the methanolic extract of Rauvolfia caffra Sond. was identified as the most promising at suppressing PTZ induced seizure-like behaviour in a zebrafish larvae model. Subsequent bioactivity-guided fractionation and spectroscopic structural elucidation resulted in the isolation and identification of two tryptoline derivatives; a previously unreported alkaloid to which we assigned the trivial name rauverine H (1) and the known alkaloid pleiocarpamine (2). Pleiocarpamine was found to reduce PTZ-induced seizures in a dose-dependent manner. CONCLUSIONS: Accordingly, pleiocarpamine represents a promising scaffold for the development of new anti-seizure therapeutic compounds. Furthermore, the results of this study provide preliminary evidence to support the traditional use of Rauvolfia caffra Sond. in the treatment and management of epilepsy. These findings warrant further studies on the anti-epileptic potential of Rauvolfia caffra Sond. using other models.

Simultaneous determination of five alkaloids from Rauvolfia vomitoria in rat plasma by LC-MS/MS: Application to a comparative pharmacokinetic study in normal and type 2 diabetic rats.

Rauvolfia vomitoria is widely distributed in the tropical regions of Africa and Asia, and has been used in traditional folk medicine in China. Indole alkaloids were found to be major bioactive components, while the effects of diabetes mellitus on the pharmacokinetic parameters of the components have not been reflected in vivo. In this study, an efficient and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous determination of five ingredients of R. vomitoria in rats. Detection was implemented in multiple-reaction-monitoring mode with an electrospray positive-ionization source. Validation parameters were all in accordance with the current criterion. The established method was effectively employed to compare the pharmacokinetic behaviors of five alkaloids (reserpine, yohimbine, ajmaline, ajmalicine, and serpentine) between normal and type 2 diabetic rats. The single-dose pharmacokinetic parameters of the five alkaloids were determined in normal and diabetic rats after oral administration of 100 and 200 mg/kg body weight. The results indicated that diabetes mellitus significantly altered the pharmacokinetic characteristics of yohimbine, ajmaline, and ajmalicine after oral administration in rats. This is an attempt to provide some evidence for clinicians that may serve as a guide for the use of antidiabetic medicine in clinical practice.

Peraksine derivatives with potential anti-inflammatory activities from the stems of Rauvolfia vomitoria.

Five new peraksine derivatives rauvomine C-G (1-5) along with four known analogues (6-9) were isolated from the stems of Rauvolfia vomitoria Afzel. (Apocynaceae). Structural determinations of the new monoterpene indole alkaloids were elucidated via comprehensive spectroscopic analyses and ECD calculations. Rauvomine C (1) with an unprecedented framework type represents the first example of C18 peraksine-type nor-monoterpene indole alkaloid featuring a chlorine atom at C-16 and its plausible biosynthetic pathway was also proposed. All the isolates were evaluated for their anti-inflammatory, cytotoxic, and acetylcholinesterase inhibitory activities. Among them, the new framework alkaloid rauvomine C (1) showed significant anti-inflammatory activities on NO production in LPS-induced RAW264.7 mouse macrophages with IC50 value of 10.76 µM. Additionally, peraksine-type alkaloids featuring pyran ring (5, 8, and 9) exhibited potential anti-inflammatory activities with IC50 values ranging from 17.52 to 20.99 µM.

In Vitro Studies on Antioxidant and Anti-Parasitic Activities of Compounds Isolated from Rauvolfia caffra Sond.

As part of an ongoing study of natural products from local medicinal plants, the methanol extract of stem bark of Rauvolfia caffra Sond was investigated for biological activity. Column chromatography and preparative thin-layer chromatography were used to isolate lupeol (1), raucaffricine (2), N-methylsarpagine (3), and spegatrine (4). The crude extract, fractions and isolated compounds were tested for anti-oxidant, antitrypanosomal and anti-proliferation activities. Two fractions displayed high DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity and reducing power with IC50 (The half maximal inhibitory concentration) and IC0.5 values of 0.022 ± 0.003 mg/mL and 0.036 ± 0.007 mg/mL, and 0.518 ± 0.044 mg/mL and 1.076 ± 0.136 mg/mL, respectively. Spegatrine (4) was identified as the main antioxidant compound in R. caffra with IC50 and IC0.5 values of 0.119 ± 0.067 mg/mL and 0.712 ± 0 mg/mL, respectively. One fraction displayed high antitrypanosomal activity with an IC50 value of 18.50 µg/mL. However, the major constituent of this fraction, raucaffricine (2), was not active. The crude extract, fractions and pure compounds did not display any cytotoxic effect at a concentration of 50 µg/mL against HeLa cells. This study shows directions for further in vitro studies on the antioxidant and antitrypanosomal activities of Rauvolfia caffra Sond.

Characterization of hippocampal histomorphology following R. vomitoria root extract treatment / Caracterización de la histomorfología del hipocampo después del tratamiento con extracto de la raíz de R. vomitoria

Rauwolfia vomitoria Afzel. is an antipsychotic plant used by several African communities in the management of psychiatric conditions with good outcomes. Concerns about its dosages on brain activity lead to this investigation of its action on the hippocampal microstructure.Twenty-four adult male Wistar rats of average weight 200 g, were assigned into four groups (n = 6): control; 200, 300 and 400 mg/kg body weight of RVroot bark extract, respectively. The administration was once daily, and orally for seven days. Daily observation of the animals was done till on day eight when they were sacrificed after deep anaesthesia. Each brain was processed for histology and immunohistochemical studies. Animals in the 200, 300 and 400 mg/kg RV groups appeared generally dull and drowsy, and barely fed. Their hippocampal histology showed neuronal atrophy and karyorrhexis, with no difference in cell count, although the pyramidal cell numbers decreased in the 300 and 400 mg/kg RV groups. Neuron-specific enolase decreased in the 400 mg/kg RV group, while neurofilament decreased in all test groups. Glial fibrillary acidic protein expression and density increased in the 200 and 300 mg/kg RV groups, but not the 400 mg/kg RV group, all compared with the control group.The given doses of RV root bark extractin adult Wistar rats showed sedative activities with hippocampal histopathological changes, which may not be reversible, thereby leading to the hippocampal functional deficit.

Introducción: Rauwolfia vomitoria (RV) Afzel es una planta antipsicótica utilizada por varias comunidades africanas en el tratamiento de enfermedades psiquiátricas con buenos resultados. Las preocupaciones sobre sus efecto sobre la actividad cerebral conducen a esta investigación de su acción sobre la microestructura del hipocampo.Materiales y métodos: Se asignaron veinticuatro ratas Wistar macho adultas de un peso medio de 200 g, en cuatro grupos (n = 6): control; 200, 300 y 400 mg / kg de peso corporal de extracto de corteza de raíz de RV, respectivamente. La administración fue una vez al día y por vía oral durante siete días. Se realizó una observación diaria de los animales hasta el día ocho, cuando fueron sacrificados después de una anestesia profunda. Cada cerebro fue procesado para estudios histológicos e inmunohistoquímicos.Resultados: Los animales en los grupos de RV de 200, 300 y 400 mg / kg parecían generalmente apagados y somnolientos, y apenas alimentados. Su histología hipocampal mostró atrofia neuronal y cariorrexis, sin diferencia en el recuento celular, aunque el número de células piramidales disminuyó en los grupos de RV de 300 y 400 mg / kg. La enolasa específica de neuronas disminuyó en el grupo de RV de 400 mg / kg, mientras que el neurofilamento disminuyó en todos los grupos de prueba. La expresión y densidad de la proteína fibrilar ácida glial aumentó en los grupos de RV de 200 y 300 mg / kg, pero no en el grupo de RV de 400 mg / kg, todos en comparación con el grupo de control.Conclusión: Las dosis administradas de extracto de corteza de raíz de RV en ratas Wistar adultas mostraron actividades sedantes, con cambios histopatológicos del hipocampo, que pueden no ser reversibles, lo que conduce al déficit funcional del hipocampo.

Effect of indole alkaloids from roots of Rauvolfia ligustrina in the noradrenergic neurotransmission.

The new glucosyl sarpagan alkaloid designated as 21(R*)-(O-ß-glucosyl)-hydroxy-sarpagan-17-oic acid, along with eleven known alkaloids were isolated from a soluble alkaloidal fraction from the ethanol extract of Rauvolfia ligustrina. Their structures were elucidated by interpretation of spectroscopic data (1D and 2D NMR), HRESIMS experiment, GIAO 13C NMR calculations, and comparison with literature data. All the isolated alkaloids were screened by their neuroinhibitory effects using the electrically stimulated mice vas deferens bioassay. Compounds 1, 2 and 9 presented a potent inhibitory effect in the neurotransmission while 3 and 11 showed an acute neuroexcitatory effect. Compound 10 exhibited a very effective post-synaptic inhibitory activity.

Expanding the Diversity of Plant Monoterpenoid Indole Alkaloids Employing Human Cytochrome P450 3A4.

Human drug-metabolizing cytochrome P450 monooxygenases (CYPs) have enormous substrate promiscuity; this makes them promising tools for the expansion of natural product diversity. Here, we used CYP3A4 for the targeted diversification of a plant biosynthetic route leading to monoterpenoid indole alkaloids. In silico, in vitro and in planta studies proved that CYP3A4 was able to convert the indole alkaloid vinorine into vomilenine, the former being one of the central intermediates in the ajmaline pathway in the medicinal plant Rauvolfia serpentina (L.) Benth. ex Kurz. However, to a much larger extent, the investigated conversion yielded vinorine (19R,20R)-epoxide, a new metabolite with an epoxide functional group that is rare for indole alkaloids. The described work represents a successful example of combinatorial biosynthesis towards an increase in biodiversity of natural metabolites. Moreover, characterisation of the products of the in vitro and in planta transformation of potential pharmaceuticals with human CYPs might be indicative of the route of their conversion in the human organism.

Murine's amygdala microstructure and elevated plus maze activities following R. vomitoria root bark and G. latifolium leaf extracts administration.

R. vomitoria (RV), a plant used locally in the management of psychotic disorders, adversely affects the brain functionally and structurally. Such adverse reports, as well as the potential of G. latifolium (GL) to mitigate same warranted this investigation on the combined actions of RV and GL on the amygdala. Twenty-four male CD-1 mice weighing 22-27 g were divided into four groups (n = 6): Control (20 ml/kg body weight, b.w., distilled water); RV (200 mg/kg b.w.), GL (200 mg/kg b.w.), and RV (200 mg/kg b.w.) and GL (200 mg/kg b.w.) combination orally, and for 14 days. On day 15, the elevated-plus maze test was carried out and the animals sacrificed, and processed for histological and immunohistochemical studies. Neurobehavioural results showed significant decrease (p[Formula: see text] 0.001) in stretch-attend posture, time spent in closed arms, grooming frequency, protected head-dip, as well as significantly (p [Formula: see text] 0.01) increased time spent in the open arms and unprotected head-dips of the RV group. The combined RV and GL groups showed no such differences in these parameters. Histologically, the amygdala showed hypertrophied cells, with pyknotic and karyorrhectic nuclei, and reduced expression of Nissl substance in the RV group, while the combined RV and GL group showed less degenerative features. Glial fibrillary acidic protein expression (GFAP) was increased in the RV group, while the combined RV and GL group showed reduced expression. In conclusion, RV root bark extract has adverse effects on the microstructure of murines' amygdala and their behaviour, which may be ameliorated by GL.

In vivo effects of Rauvolfia vomitoria (Apocynaceae) ethanolic extract on sexual performance and reproductive activity in male rats.

Plants and plant-derived products have a long history in the treatment of sexual disorders. Rauvolfia vomitoria is one of such plant used traditionally for the enhancement of male sexual and reproductive activity. This study was carried out to elucidate the potential activity of R. vomitoria ethanolic extract on sexual behaviour and male reproductive function. Twenty-five male rats were assigned to five groups and orally treated with distilled water (control), sildenafil citrate (standard) and R. vomitoria ethanolic extract (50, 100 and 200 mg/kg BW) for 22 days. Sexual behaviour parameters such as mount latency (ML), intromission latency (IL), ejaculation latency (EL), mount frequency (MF), intromission frequency (IF), ejaculation frequency (IF) and post-ejaculatory interval (PEI) were recorded at day 0, 1, 8, 15 and 22. The reproductive function including reproductive organ weights, testicular histology and sperm parameters was also assessed. Results showed enhancement in sexual behaviour through significant reduction (p < .01) in ML, IL and PEI and significant increase (p < .01) in EL, MF IF and EF. The extract also caused an increase in sperm count, motility and transit. Present findings demonstrate the ability of R. vomitoria ethanolic extract to improve male sexual behaviour and reproductive activity in rats.

Attenuation of potassium dichromate and sodium arsenite toxicities by methanol extract of Rauvolfia vomitoria in mice.

OBJECTIVES: Exposure to arsenic and hexavalent chromium is a major public health concern especially in the developing part of the world and there is paucity of information on reliable treatment modalilities. It is in this regard that this study evaluates the efficacy of methanol leaf extract of Rauvolfia vomitoria (MRV) when used as pretreatment agent against potassium dichromate (K2Cr2O7) and sodium arsenite (NaAsO2) exposure. METHODS: Swiss albino mice between 7 and 10 weeks old were divided into eight cohorts of five animals each. Treatment groups consisted of a distilled water control, MRV alone (275 mg/kg po daily), K2Cr2O7 (12.0 mg/kg, single ip injection) +/- MRV pretreatment, NaAsO2 (2.5 mg/kg, single ip injection) +/- MRV pretreatment, Na2AsO2 + K2Cr2O7 +/- MRV pretreatment. MRV was given for seven consecutive days, while K2Cr2O7 and NaAsO2 were injected on day seven of the experiment. The frequency of micronucleated polychromatic erythrocytes (mPCEs) was determined in bone marrow cells, while aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities were assessed in the plasma. Hepatic glutathione (GSH), malondialdehyde (MDA), catalase (CAT) and glutathione-S-transferase (GST) levels were also determined. RESULTS: The NaAsO2 and K2Cr2O7 significantly (p<0.05) increased mPCE formation, AST, ALT, and CAT when compared with the control. Simultaneous exposure to NaAsO2 and K2Cr2O7 further increased the levels of the markers. Furthermore, GSH and GST were significantly reduced by NaAsO2 or K2Cr2O7 or their combination. Pretreatment with MRV reversed the markers towards that of control. CONCLUSIONS: Methanol extract of Rauvolfia vomitoria may therefore ameliorate NaAsO2 and K2Cr2O7-induced toxicities via reduction of oxidative stress and fortification of anti-oxidant system.

Phenolic constituents and inhibitory effects of the leaf of Rauvolfia vomitoria Afzel on free radicals, cholinergic and monoaminergic enzymes in rat's brain in vitro.

OBJECTIVES: Rauvolfia vomitoria is a medicinal plant used traditionally in Africa in the management of several human diseases including psychosis. However, there is inadequate scientific information on the potency of the phenolic constituents of R. vomitoria leaf in the management of neurodegeneration. Therefore, this study characterized the phenolic constituents and investigated the effects of aqueous and methanolic extracts of R. vomitoria leaf on free radicals, Fe2+-induced lipid peroxidation, and critical enzymes linked to neurodegeneration in rat's brain in vitro. METHODS: The polyphenols were evaluated by characterizing phenolic constituents using high-performance liquid chromatography coupled with diode array detector (HPLC-DAD). The antioxidant properties were assessed through the extracts ability to reduce Fe3+ to Fe2+; inhibit ABTS, DPPH, and OH radicals and Fe2+-induced lipid peroxidation. The effects of the extracts on AChE and MAO were also evaluated. RESULTS: The phenolic characterization of R. vomitoria leaf revealed that there were more flavonoids present. Both aqueous and methanolic extracts of R. vomitoria leaf had inhibitory effects with the methanolic extract having higher significant (p≤0.05) free radicals scavenging ability coupled with inhibition of monoamine oxidases. However, there was no significant (p≤0.05) difference obtained in the inhibition of lipid peroxidation and cholinesterases. CONCLUSION: This study suggests that the rich phenolic constituents of R. vomitoria leaf might contribute to the observed antioxidative and neuroprotective effects. The methanolic extract was more potent than the aqueous extract; therefore, extraction of R. vomitoria leaf with methanol could offer better health-promoting effects in neurodegenerative condition.

HPLC phenolic fingerprinting, antioxidant and anti-phosphodiesterase-5 properties of Rauwolfia vomitoria extract.

Background In Nigerian traditional medicine, Rauwolfia vomitoria has been reported to be useful in the management of various human diseases, but there is no relevant information to substantiate its involvement in managing diseases arising from vascular dysfunction and oxidative stress. However, this study sought to investigate the antioxidant property of R. vomitoria and its effect on phophodiesterase-5 activity in vitro. Methods The antioxidant property was assessed through ferric-reducing antioxidant power (FRAP), copper chelation, and ABTS radical-scavenging activity. In addition, the effect of R. vomitoria on phosphodiesterase-5 (PDE-5) activity was assessed in vitro. Furthermore, analysis of phenolic compounds present in R. vomitoria was carried out using high-performance liquid chromatography (HPLC). Results The findings in this study revealed that R. vomitoria inhibited PDE-5 in a dose-dependent manner (IC50 = 252.42 µg/mL). Furthermore, the antioxidant activity of R. vomitoria was established through FRAP (19.68 mg AAE/g), ABTS radical-scavenging ability (74.25 mmol TEAC/g), and Cu2+-chelating ability (IC50 = 0.13 mg/mL). Conclusions The antioxidant property of R. vomitoria and its inhibitory effect on PDE-5 could be useful in the management of diseases arising from vascular dysfunction and oxidative stress.

Biotechnological interventions on the genus Rauvolfia: recent trends and imminent prospects.

Rauvolfia spp., also known as devil peppers, are a group of evergreen shrubs and trees. Among the ~ 76 various species, Rauvolfia serpentina is the most important one as it finds its use as an important medicinal plant. It is commonly known as the Indian snakeroot plant or Sarpagandha. The plant is rich in multiple secondary metabolites. Some of the well-known secondary metabolites are reserpine, ajmaline, ajmalicine, serpentine, yohimbine, etc. Alkaloids are also found in all parts of the plant but the richest sources are the roots. Since ancient times, roots (mainly due to reserpine) have been utilized in various Ayurvedic and Unani medicinal preparations for the treatment of diseases like hypertension, anxiety, insomnia and schizophrenia. Apart from this, there are many other pharmacological and ethnobotanical uses of this plant. There are a number of published reports regarding tissue culture techniques on Rauvolfia spp. The current review mainly illustrates and discusses the various in vitro biotechnological aspects such as direct regeneration, indirect regeneration via callus formation, somatic embryogenesis, synthetic seed production, hairy root culture, polyploidy induction and secondary metabolite estimation, which provides significant ideas regarding the ongoing research activities and future prospects related to the genetic improvement of this genus.

R. nukuhivensis acts by reinforcing skin barrier function, boosting skin immunity and by inhibiting IL-22 induced keratinocyte hyperproliferation.

Rauvolfia nukuhivensis is a well-known plant used for its wide range of beneficial effects in Marquesas islands. It is made up of diverse indole alkaloids and is used as traditional medicine for skin application. The actual mechanism behind the virtue of this plant is still unknown. Hence, in this study we aimed at deciphering the impact of R. nukuhivensis on skin immune system in context of (1) homeostasis, (2) pathogen infection and (3) inflammation. Here we show that R. nukuhivensis enhances cellular metabolic activity and wound healing without inducing cellular stress or disturbing cellular homeostasis. It reinforces the epithelial barrier by up-regulating hBD-1. Nevertheless, in pathogenic stress, R. nukuhivensis acts by preparing the immune system to be reactive and effective directly. Indeed, it enhances the innate immune response by increasing pathogens sensors such as TLR5. Finally, R. nukuhivensis blocks IL-22 induced hyperproliferation via PTEN and Filaggrin up-regulation as well as BCL-2 downregulation. In conclusion, this study provides evidence on the several cutaneous application potentials of R. nukuhivensis such as boosting the immune response or in restoring the integrity of the epithelial barrier.

Pectic polysaccharides extracted from Rauvolfia verticillata (Lour.) Baill. var. hainanensis Tsiang ameliorate ulcerative colitis via regulating the MAPKs and NF-κB pathways in dendritic cells.

This study was to investigate the effects and mechanisms of pectic polysaccharides (PP) extracted from Rauvolfia verticillata (Lour.) Baill. var. hainanensis Tsiang on dextran sulphate sodium (DSS)-induced ulcerative colitis (UC). Eighty female BALB/c mice were randomly divided into four groups: Control, DSS, DSS + salicylazosulfapyridine (SASP), and DSS+ PP. The disease activity index (DAI), overall physical activity, and blood stool were monitored daily to evaluate severity of UC. Histological scores of the colon were observed. The expression of nuclear factor κB (NF-κB) and mitogen-activated protein kinase (MAPKs) pathways in colon tissues and bone marrow-derived dendritic cells (DCs) was assessed by western blot, immunohistochemistry, electrophoretic mobility shift assay (EMSA) and real time polymerase chain reaction (RT-PCR). Cytokines were measured by enzyme-linked immunosorbent assay (ELISA). The overall physical activity, DAI and histological scores decreased in DSS+SASP and DSS+PP groups, compared with the DSS-alone group. Also, tumour necrosis factor α (TNF-α) and interleukin 6 (IL-6) reduced significantly while the expression of IκBα was up-regulated, extracellular signal-regulated kinase (ERK), Jun N-terminal kinase (JNK) and p38 were activated, in DSS+SASP and DSS+PP groups. PP inhibited activation of MAPKs and NF-κB pathways in the bone-marrow-derived DCs. In conclusion, PP significantly ameliorated murine DSS-induced UC model, via regulation of MAPKs and NF-κB pathways in DCs.

Isolation, Chemical Profile and Antimalarial Activities of Bioactive Compounds from Rauvolfia caffra Sond.

In this study, the chemical profile of a crude methanol extract of Rauvolfia caffra Sond was determined by ultra-performance liquid chromatography-mass spectrometry (UPLC-MS). Column chromatography and preparative thin layer chromatography were used to isolate three indole alkaloids (raucaffricine, N-methylsarpagine and spegatrine) and one triterpenoid (lupeol). The antiplasmodial activity was determined using the parasite lactate dehydrogenase (pLDH) assay. The UPLC-MS profile of the crude extract reveals that the major constituents of R. caffra are raucaffricine (m/z 513.2) and spegatrine (m/z 352.2). Fraction 3 displayed the highest antiplasmodial activity with an IC50 of 6.533 µg/mL. However, raucaffricine, isolated from the active fraction did not display any activity. The study identifies the major constituents of R. caffra and also demonstrates that the major constituents do not contribute to the antiplasmodial activity of R. caffra.

Inhibition of pancreatic cancer stem cells by Rauwolfia vomitoria extract.

The poor treatment outcomes of pancreatic cancer are linked to an enrichment of cancer stem cells (CSCs) in these tumors, which are resistant to chemotherapy and promote metastasis and tumor recurrence. The present study investigated an extract from the root of the medicinal plant Rauwolfia vomitoria (Rau) for its activity against pancreatic CSCs. In vitro tumor spheroid formation and CSC markers were tested, and in vivo tumorigenicity was evaluated in nude mice. Rau inhibited the overall proliferation of human pancreatic cancer cell lines with a 50% inhibitory concentration (IC50) ranging between 125 and 325 µg/ml, and showed limited cytotoxicity towards normal epithelial cells. The pancreatic CSC population, identified using cell surface markers or a tumor spheroid formation assay, was significantly reduced, with an IC50 value of ~100 µg/ml treatment for 48 h and ~27 µg/ml for long-term tumor spheroid formation. The levels of CSC-related gene Nanog and nuclear ß-catenin were decreased, suggesting suppression of the Wnt/ß-catenin signaling pathway. In vivo, 20 mg/kg of Rau administered five times per week by oral gavage significantly reduced the tumorigenicity of PANC-1 cells in immunocompromised mice. Taken together, these data showed that Rau preferentially inhibited pancreatic cancer stem cells. Further investigation is warranted to examine the potential of Rau as a novel treatment for pancreatic cancer.

Simultaneous determination of intestinal permeability and potential drug interactions of complex mixtures using Caco-2 cells and high-resolution mass spectrometry: Studies with Rauwolfia serpentina extract.

Caco-2 cells are a commonly used model for estimating the intestinal bioavailability of single chemical entity pharmaceuticals. Caco-2 cells, when induced with calcitriol, also express other biological functions such as phase I (CYP) and phase II (glucuronosyltransferases) drug metabolizing enzymes which are relevant to drug-supplement interactions. Intestinal bioavailability is an important factor in the overall safety assessment of products consumed orally. Foods, including herbal dietary supplements, are complex substances with multiple chemical components. Because of potential interactions between components of complex mixtures, more reliable safety assessments can be obtained by studying the commercial products "as consumed" rather than by testing individual chemical components one at a time. The present study evaluated the apparent intestinal permeability (Papp) of a model herbal extract, Rauwolfia serpentina, using both whole plant extracts and the individual purified Rauwolfia alkaloids. All test compounds, endpoint substrates, and their metabolites were quantified using liquid chromatography and high-resolution mass spectrometry. The Papp values for individual Rauwolfia alkaloids were comparable whether measured individually or as components of the complete extract. Both Rauwolfia extract and all individual Rauwolfia alkaloids except yohimbine inhibited CYP3A4 activity (midazolam 1'-hydroxylation). Both Rauwolfia extract and all individual Rauwolfia alkaloids except corynanthine and reserpic acid significantly increased glucuronosyltransferase activity (glucuronidation of 4-methylumbelliferone). The positive control, ketoconazole, significantly inhibited both CYP3A4 and glucuronosyltransferase activities. These findings suggest that the Caco-2 assay is capable of simultaneously identifying both bioavailability and potentially hazardous intestinal drug-supplement interactions in complex mixtures.