Bioactive 5/5/5/6 Four-Ring System Iridoids from Plumeria alba L.

Two rare 5/5/5/6 four-ring system iridoids, allamancins A and B (1 and 2) together with one known biogenetically related iridoid derivative, 3-O-methyallamancin (3) were isolated from the flowers of Plumeria alba L. The structures of these iridoid derivatives were determined by comprehensive spectroscopic analyses. The absolute configuration of 1 was confirmed by X-ray crystallographic analysis. The inhibitory activities of compounds 1-3 against nitric oxide (NO) production induced and three cancer cell lines were evaluated in vitro. Compounds 1 and 3 showed inhibitory activities on NO production with IC50 values of 18.3±0.12 and 22.1±0.14 µM, respectively. Compounds 1-3 showed moderate inhibitory activities against cancer cell lines of A549, Hela and MCF-7.

Quinoline, Indole, and Isogranatanine Alkaloids from Malayan Leuconotis eugeniifolia.

Nine new alkaloids, eugeniinalines A-H (1-8) and (+)-eburnamenine N-oxide (9), comprising one quinoline, six indole, and two isogranatanine alkaloids, were isolated from the stem-bark extract of the Malayan Leuconotis eugeniifolia. The structures and absolute configurations of these alkaloids were established based on the analysis of the spectroscopic data, GIAO NMR calculations, DP4+ probability analysis, TDDFT-ECD method, and X-ray diffraction analysis. Eugeniinaline A (1) represents a new pentacyclic quinoline alkaloid with a 6/6/5/6/7 ring system. Eugeniinaline G (7) and its seco-derivative, eugeniinaline H (8), were the first isogranatanine alkaloids isolated as natural products. The known alkaloids leucolusine (10) and melokhanine A (11) were found to be the same compound, based on comparison of the spectroscopic data of both compounds, with the absolute configuration of (7R, 20R, 21S). Eugeniinalines A and G (1 and 7) showed cytotoxic activity against the HT-29 cancer cell line with IC50 values of 7.1 and 7.2 µM, respectively.

Proteomic analysis of Cryptostegia grandiflora latex, purification, characterization, and biological activity of two osmotin isoforms.

Although latex fluids are found in >20,000 plant species, the biochemical composition and biological function of their proteins are still poorly explored. Thus, this work aimed to conduct a proteomic analysis of Cryptostegia grandiflora latex (CgLP) for subsequent purification and characterization of an antifungal protein. After 2D-SDS-PAGE and mass spectrometry, 27 proteins were identified in CgLP, including a polygalacturonase inhibitor, cysteine peptidases, pathogenesis-related proteins (PR-4), and osmotins. Then, two osmotin isoforms (CgOsm) were purified, and a unique N-terminal sequence was determined (1ATFDIRSNCPYTVWAAAVPGGGRRLDRGQTWTINVAPGTA40). The PCR products revealed a cDNA sequence of 609 nucleotides for CgOsm, which encoded a polypeptide with 203 amino acid residues. The structure of CgOsm has features of typical osmotin or thaumatin-like proteins (TLPs), such as 16 conserved Cys residues, REDDD and FF motifs, an acidic cleft, and three main domains. Atomic force microscopy (AFM) and bioinformatics suggested that CgOsm is associated with three chain units. This result was interesting since the literature describes osmotins and TLPs as monomers. AFM also showed that Fusarium falciforme spores treated with CgOsm were drastically damaged. Therefore, it is speculated that CgOsm forms pores in the membrane of these cells, causing the leakage of cytoplasmic content.

Effects of Rhazya Stricta plant organic extracts on human induced pluripotent stem cells derived neural stem cells.

Rhazya Stricta (R. stricta) has been employed as a natural remedy for several diseases for centuries. Numerous studies revealed that R. stricta extracts contain alkaloids, tannins, and flavonoids that possess antimicrobial, anticancer, antihypertensive, and antioxidant activities. In this study, we examined the effects of organic extracts from different parts of R. stricta plant on human pluripotent stem cells (hiPSCs)-derived neural stem cells (NSCs) for medical purposes. NSCs were incubated with different concentrations of organic extracts from the leaves, stem, and fruits, and we assessed the growth and viability of the cells by using MTS assay and the chemical composition of the potential plant extract by using gas chromatography-mass spectrometry (GC/MS). Our results revealed that the methanolic extract from the stem increased NSCs growth significantly, particularly at a concentration of 25 µg/ml. GC/MS analysis was utilized to identify the potential compounds of the methanolic extract. In conclusion, our results demonstrated for the first time that methanolic stem extract of R. stricta contains compounds that can positively impact NSCs growth. These compounds can be further investigated to determine the potential bioactive compounds that can be used for research and medical purposes.

Monoterpenoid indole alkaloid adducts and dimers from Melodinus fusiformis.

Eight unprecedented monoterpenoid indole alkaloid (MIA) adducts and dimers, melofusinines A-H (1-8), and three undescribed melodinus-type MIA monomers, melofusinines I-K (9-11), together with six putative biogenetic precursors were isolated from the twigs and leaves of Melodinus fusiformis Champ. ex Benth. Compounds 1 and 2 are unusual hybrid indole alkaloids incorporating an aspidospermatan-type MIA with a monoterpenoid alkaloid unit via C-C coupling. Compounds 3-8 feature the first MIA dimers constructed through an aspidospermatan-type monomer and a rearranged melodinus-type monomer with two different types of couplings. Their structures were elucidated by spectroscopic data, single crystal X-ray diffraction, and calculated electric circular dichroism spectra analysis. In addition, dimers 5 and 8 showed significant neuroprotection effects on MPP +-injured primary cortical neurons.

Phenolic Composition, Wound Healing, Antinociceptive, and Anticancer Effects of Caralluma europaea Extracts.

Caralluma europaea (Guss.) is an important medicinal plant widely used in Morocco for various traditional purposes. Our work aimed to evaluate the phenolic composition, wound healing, antinociceptive, and anticancer activities of C. europaea extracts. Moreover, this study assessed the beneficial effect of C. europaea phytocompounds on the TRADD, cyclooxegenase-2, Wnt/ß-catenin, and tyrosine kinase signaling pathways. The wound healing effect of C. europaea formulations against skin burn was evaluated for 21 days. The cytotoxic effect of the C. europaea extracts was evaluated against human leukemic (K562 and HL60) and liver cancer cell lines (Huh-7) using the MTT test. All the phytoconstituents identified by UHPLC in the polyphenols were docked for their inhibitory power on protein casein kinase-1, glycogen synthase kinase-3-ß, cyclooxegenase-2, tyrosine kinase, and TRADD. Luteolin and kaempferol are the main compounds identified in C. europaea polyphenols. The group treated with polyphenols showed the greatest wound contractions and all tested extracts presented a significant antinociceptive effect. Polyphenols showed a remarkable antitumoral activity against the K562, HL60 and Huh-7 cell lines. Saponins exerted an important cytotoxic effect against the Huh-7 cell line, whereas no cytotoxicity was observed for the hydroethanolic and flavonoids extracts. Hesperetin and trimethoxyflavone presented the highest docking G-score on tyrosine kinase and cyclooxygenase, respectively.

Two new monoterpenoid indole alkaloids from the kernels of Kopsia arborea.

Two new monoterpenoid indole alkaloids, (2 R, 7 R, 16 R, 20 R, 21S)-12-hydroxypleiocarpine (1) and (2S, 7 R, 16S, 20 R, 21S)-N-methoxycarbonyl-11,12-methylenedioxy-Δ14,15-kopsinaline (2), along with six known alkaloids were isolated from the methanol extract of the kernels of Kopsia arborea. Their structures including the absolute configurations were elucidated by HRESIMS, NMR spectroscopy, and quantum computational methods. Their cytotoxicity against two human cancer cell lines were also evaluated.

Hancornia speciosa serum latex fraction: a non-allergenic biomaterial / Fração soro do látex de Hancornia speciosa: um biomaterial não alergênico

Plant-derived products can assist in the healing process of dermal wounds. It has been demonstrated that Hancornia speciosa latex present angiogenic, osteogenic, anti-inflammatory, and antioxidant activities. Then, it could contribute to the wound healing process. However, natural products in contact with skin may cause dermatitis. The objective of this work was to evaluate the allergic and irritant potential of H. speciosa serum fraction latex using in vitro assays. The obtained results showed that the H. speciosa serum fraction latex has a slightly irritant potential and is not cytotoxic neither allergenic for human cells. Moreover, we identified a remarkable low amount of proteins in this material in comparison to Hevea brasiliensis latex. This result could explain the non-allergenic potential of H. speciosa serum fraction latex because proteins present in latex are the main responsible for allergy. This biomaterial could be used as a non-allergenic source for development of new medicines.

Produtos derivados de plantas podem auxiliar no processo de cicatrização de feridas cutâneas. Foi demonstrado que o látex de Hancornia speciosa apresenta atividades angiogênicas, osteogênicas, antiinflamatórias e antioxidantes. Então, este biomaterial pode contribuir para o processo de cicatrização de feridas. No entanto, produtos naturais em contato com a pele podem causar dermatites. O objetivo deste trabalho foi avaliar o potencial alérgico e irritante do látex da fração soro de H. speciosa por meio de ensaios in vitro. Os resultados obtidos mostraram que o látex da fração do soro de H. speciosa possui um potencial pouco irritante e não é citotóxico nem alergênico para células humanas. Além disso, foi identificado uma notável baixa quantidade de proteínas neste material em comparação ao látex de Hevea brasiliensis. Esse resultado poderia explicar o potencial não alergênico do látex da fração soro de H. speciosa, pois as proteínas presentes no látex são as principais responsáveis pela alergia. Este biomaterial pode ser utilizado como fonte não alergênica para desenvolvimento de novos medicamentos.

Evaluation of nutritional composition of flour residue of mangaba processing / Avaliação dos fatos nutricionais do processamento do resíduo da farinha de mangaba

Among several fruits, mangaba (Hancornia speciosa Gomes), it aroused the interest of producers and consumers due to its attractive sensory characteristics and health beneficial properties (high nutritional value and presence of bioactive substances), thus, this work evaluates the nutritional factors of the flour residue of mangaba processing that is despised by the food industry, and the influence of temperature on its production. The mangaba processing residue was splited in two main groups: in natura sample (control), and other for preparation of flour that was dried at 50 °C and divided into two other groups: treatment A (flour with roasts at 110 °C and 130 °C) and treatment B (flour from drying at 50 °C). The nutritional characteristics of flours were analyzed considering the chemical parameters: pH, titratable total acidity and soluble solids, in addition to the determination of moisture content, total lipids, total dietary fiber and ash, total energy value, antioxidant activity, phytochemical screening, quantification of phenolic compounds and flavonoids, as well as technological functional properties (water absorption index (WAI), water solubility index (WSI), milk absorption index (MAI) and milk solubility index (MSI) and oil absorption index (OAI). The results showed that the bioactive compounds present in the extracts do not have significant properties of acting as free radical kidnappers. The heat treatment, performed in the flour of mangaba processing residues, influenced the nutritional factors and properties of absorption and solubility, which showed statistical differences. These results show that the flour is a viable alternative for the energy enrichment of diets, contributing to the development of new products, the reduction of the disposal of these residues and consequently to the minimization of the environmental impact.

Dentre as diversas frutas a mangaba (Hancornia speciosa Gomes), despertou interesse de produtores e consumidores devido às suas características sensoriais atrativas e propriedades benéficas à saúde (elevado valor nutricional e presença de substâncias bioativas), assim, o trabalho avaliar os fatores nutricionais do resíduo da farinha de processamento de mangaba que é desprezado pela indústria alimentícia e, a influência da temperatura na sua produção. O resíduo de processamento da mangaba foi dividido em dois lotes, sendo um deles utilizado para as análises in natura (amostra controle) e o outro para a confecção da farinha que foi seca a 50 °C, e dividida em dois lotes: tratamento A (farinha com torras a 110 °C e 130 °C) e no tratamento B (farinha oriunda da secagem a 50 °C). Analisou-se as características nutricionais de farinhas considerando os parâmetros químicos: pH, acidez total titulável e sólidos solúveis, além da determinação do teor de umidade, lipídios totais, fibra alimentar total e cinzas, valor energético total, atividade antioxidante, triagem fitoquímica, quantificação de compostos fenólicos e flavonoides, bem como as propriedades funcionais tecnológicas (índice de absorção de água (IAA), índice de solubilidade em água (ISA), índice de absorção de leite (IAL) e índice de solubilidade em leite (ISL) e índice de absorção de óleo (IAO). Na análise foi inferido que os compostos bioativos presentes nos extratos não possuem propriedades significativas de agir como sequestradores de radicais livres. O tratamento térmico, realizado na farinha de resíduos de processamento de mangaba, influenciou nos dados dos fatores nutricionais e das propriedades de absorção e solubilidade, os quais apresentaram diferenças estatísticas. Estes resultados credenciam a farinha como uma alternativa viável para o enriquecimento energético de dietas, contribuindo para o desenvolvimento de [...].

New Pregnane Glycosides from Mandevilla dardanoi and Their Anti-Inflammatory Activity.

Mandevilla Lindl. is an important genus of the Apocynaceae family, not only as ornamental plants but also for its medicinal uses. In Brazil, Mandevilla species are indicated to treat asthma and skin infections, their anti-inflammatory potential and wound healing properties are also reported in the literature. Concerning their chemical composition, this group of plants is a conspicuous producer of pregnane glycosides. Mandevilla dardanoi is an endemic species from the Brazilian semiarid region not studied by any phytochemical methods. In view of the medicinal potential of Mandevilla species, this study aimed to isolate new pregnane glycosides from M. dardanoi. To achieve this main goal, modern chromatography techniques were employed. Five new pregnane glycosides, dardanols A-E, were isolated from the roots of M. dardanoi by HPLC. Their structures were determined using extensive 1D and 2D-NMR and mass spectrometry (MSn and HRESIMS) data. The cytotoxicity and the anti-inflammatory potential of these compounds were evaluated. The first was evaluated by measuring proinflammatory cytokines and nitric oxide production by stimulated macrophages. Dardanols were able to inhibit the production of nitric oxide and reduce IL-1ß and TNF-α. The current work demonstrates the chemodiversity of Brazilian semiarid species and contributes to amplifying knowledge about the biological potential of the Mandevilla genus.

Pro-Apoptotic and Pro-Autophagic Properties of Cardenolides from Aerial Parts of Pergularia tomentosa

Pergularia tomentosa L., a milkweed tropical plant belonging to the family Asclepiadaceae, is a rich source of unusual cardiac glycosides, characterised by transfused A/B rings and a sugar moiety linked by a double link, generating a dioxanoid structure. In the present report, five cardenolides isolated from the aerial parts of the plant (calactin, calotropin, 12ß-hydroxycalactin, 12ß,6'-dihydroxycalotropin, and 16α-hydroxycalotropin) were investigated for their biological effects on a human hepatocarcinoma cell line. Cell viability was monitored by an MTT assay. The occurrence of apoptosis was evaluated by detecting caspase-3 activation and chromatin fragmentation. The ability of these compounds to induce autophagy was analysed by monitoring two markers of the autophagic process, LC3 and p62. Our results indicated that all cardenolides had cytotoxic effects, with IC50 ranging from 0.127 to 6.285 µM. All compounds were able to induce apoptosis and autophagy, calactin being the most active one. Some of them also caused a reduction in cell migration and a partial block of the cell cycle into the S-phase. The present study suggests that selected cardenolides from aerial parts of P. tomentosa, particularly calactin, possess potentially desirable properties for further investigation as anticancer agents.

Characterization of alkaloids in bark extracts of Geissospermum vellosii by HPLC-UV-diode array-multistage high-resolution mass spectrometry.

A number of analytical studies, started in the sixties of the last century, concerning the stem bark of Geissospermum vellosii, have documented the presence of a number of indole alkaloids whose molecular identity was defined by NMR technique. The potential bioactivity of these compounds has inspired more recent analogous studies either devoted to structural elucidation of new alkaloid molecules or to the investigation of the role of some of them in cancer therapy. Anyway, a complete fingerprinting of the bark content is still lacking. In this paper, after a suitable extraction step, we obtain a chromatographic separation showing a number of components higher than the number of alkaloids so far described. Considering the great number of substances present in the stem bark, their identification is practically impossible to reveal by NMR techniques. As we presume that there are other stem bark unidentified alkaloids with important bioactivity, we propose to characterize their molecular structures by UV-Vis Diode Array spectrophotometry and High-Resolution Multistage Mass Spectrometry. The two adopted detection techniques were first tested on the already known Geissospermum vellosii molecules, and, after an inspection of their efficacy, were applied to the substances that have not yet been described. Herewith we propose the molecular structures of 10 substances that were never previously described, and in addition we provide experimental evidence of the presence of 6 already known substances which were never reported in the Geissospermum genus. A far more detailed description of the bark constituents is therefore provided.

Monoterpenoid Quinoline Alkaloids from Stems and Leaves of Melodinus tenuicaudatus.

Two previously undescribed monoterpenoid quinoline alkaloids, namely melotenucadines A and B, together with four known analogs, were characterized from the stems and leaves of Melodinus tenuicaudatus. The structures of the new compounds were established by extensive MS and NMR spectroscopic methods, while the absolute configuration was conducted by ECD calculations. Melotenucadine B was found to show certain cytotoxicity to MCF-7 cell (IC50 =27.3 µM).

PHARMACOLOGICAL AND MECHANISTIC STUDIES OF UREQUINONA, A MOLECULE FROM ROOTS OF PENTALINON ANDRIEUXII MUELL-ARG THAT HEALS MURINE LEISHMANIA MEXICANA INFECTION.

In this work we tested both the in vitro and in vivo anti-Leishmania mexicana activity of a molecule we originally identified in the root of Pentalinon andrieuxii Muell-Arg, a plant that is widely used in Mayan traditional medicine. The chemical name of this molecule is 24-methylcholesta-4-24(28)-dien-3-one, but for simplicity's sake, we assigned the short and trivial name of urequinona that will be used throughout this work. It induces necrosis and apoptosis of promastigotes cultured in vitro and extensive ultrastructural damage of amastigotes. It also induces production of Interleukin (IL)-2 and interferon (IFN)-γ by splenic cells from infected and urequinona treated mice stimulated in vitro with parasite antigen (Ag) but inhibits the production of IL-6 and IL-12p70 by bone-marrow-derived macrophages (BMM) infected in vitro and then treated with urequinona. It also induces activation of transcription factors such as NFkB and AP-1 (NFkB/AP-1) in RAW reporter cells. We also developed a novel pharmaceutical preparation of urequinona encapsulated in hydroxyethyl cellulose for dermal application that significantly reduced (P < 0.05) experimentally induced ear lesions of C57BL/6 mice. We conclude the preparation containing this molecule is a good candidate for a novel anti-leishmanial drug's preparation.

Monoterpene Indole Alkaloids from the Aerial Parts of Rhazya stricta Induce Cytotoxicity and Apoptosis in Human Adenocarcinoma Cells.

Chromatographic investigation of the aerial parts of the Rhazya stricta (Apocynaceae) resulted in the isolation of two new monoterpene indole alkaloids, 6-nor-antirhine-N1-methyl (1) and razyamide (2), along with six known compounds, eburenine (3), epi-rhazyaminine (4), rhazizine (5), 20-epi-sitsirikine (6), antirhine (7), and 16-epi-stemmadenine-N-oxide (8). The chemical structures were established by various spectroscopic experiments. Compounds 1-8 exhibited cytotoxic effects against three cancer cells with IC50 values ranging between 5.1 ± 0.10 and 93.2 ± 9.73 µM against MCF-7; 5.1 ± 0.28 and 290.2 ± 7.50 µM against HepG2, and 3.1 ± 0.17 and 55.7 ± 4.29 µM against HeLa cells. Compound 2 showed the most potent cytotoxic effect against all cancer cell lines (MCF-7, HepG2 and HeLa with IC50 values = 5.1 ± 0.10, 5.1 ± 0.28, and 3.1 ± 0.17 µM, respectively). Furthermore, compound 2 revealed a significant increase in the apoptotic cell population of MCF-7, HepG2, and HeLa cells, with 31.4 ± 0.2%, 29.2 ± 0.5%, and 34.9 ± 0.6%, respectively. Compound 2 decreased the percentage of the phagocytic pathway on HepG2 cells by 15.0 ± 0.1%. These findings can explain the antiproliferative effect of compound 2.

Potent immunosuppressive and anti-inflammatory bisindole alkaloids from Melodinus fusiformis.

Phytochemical investigation of Melodinus fusiformis led to a new aspidosperma-aspidosperma bisindole alkaloid (BIA), bis-19ß-hydroxyvenalstonidine (1), together with three known BIAs (2-4). The structures were established by extensive analysis of their HRESIMS, NMR data, and comparing with the reported data. BIA 1 is an almost symmetrical structure, linked by C3-C14' bond, while BIAs 2-4 are reported for the first time from the plant. The cytotoxic, immunosuppressive and anti-inflammatory activities of BIAs 1-4 were evaluated in vitro. BIAs 1, 3 and 4 showed good toxicity against MOLT-4 cell lines with IC50 values in the range of 1.5-17.5 -M. BIA 2 exhibited the strongest inhibitory effect against MCF-7 cell lines with an IC50 value of 7.1 µM. BIA 1 significantly inhibited Con A-stimulated mice splenocytes proliferation equal to that of the positive control (DXM) in a concentration-dependent manner. BIAs 1 and 2 were able to decrease the NO production in LPS-induced RAW 264.7 cells at 30 µM concentration. BIA 2 showed similar inhibition of nitric oxide release, compared to that of DXM. Furthermore, BIA 2 remarkably inhibited the levels of IL-6 and TNF-α compared to the LPS induced group. Interestingly, BIA 2 displayed an inhibitory effect on TNF-α production similar to that of dexamethasone at a concentration of 20 µM.

Monoterpenoid indole alkaloids with potential neuroprotective activities from the stems and leaves of Melodinus cochinchinensis.

A chemical study on the stems and leaves of Melodinus cochinchinensis resulted in the isolation and identification of a new monoterpenoid indole alkaloid, melodicochine A (1), together with seven known monoterpenoid indole alkaloids (2-8). The chemical structure of 1 was elucidated on the basis of extensive spectral data analyses and the known compounds were identified by comparing their experimental spectral data with the reported data in the literature. All isolated indole alkaloids were evaluated for their neuroprotective effects against 6-hydroxydopamine induced cell death in human neuroblastoma SH-SY5Y cells in vitro. Monoterpenoid indole alkaloids 1-8 exhibited notable neuroprotective effects with EC50 values in range of 0.72 ± 0.06 to 17.89 ± 0.16 µM.[Formula: see text].

Bioactive compounds and hepatoprotective effect of Hancornia speciosa gomes fruit juice on acetaminophen-induced hepatotoxicity in vivo.

Hancornia speciosa Gomes (HS) is a Brazilian fruit tree used in inflammatory disorders by folk medicine. Here we sought to investigate the antioxidant and hepatoprotective properties of HS fruit juice in acetaminophen-induced hepatoxicity model in rats, as well as to perform a comprehensive chemical characterization of phenolics and metals by mass spectrometry. HS showed hepatoprotective and antioxidant activity by decreasing MDA and liver injury markers at healthy control levels. In addition, liver histopathological analysis revealed that HS decreases hepatocellular degeneration. Chemical characterization revealed 16 different phenolics, being chlorogenic acid (150 ± 5 µg/g) and rutin (120 ± 8 µg/g) the major phenolics in HS. Among the 14 micronutrients we identified, zinc and boron were the most abundant metals detected in HS. In line with previous studies involving liver diseases, our data supports evidence that such phenolics and metals present in HS may prevent liver injury induced by acetaminophen.

Phytochemicals from Carissa carandas with potent cytotoxic and anti-inflammatory activities.

Six natural products (1-6) were isolated from the fresh leaves of Carissa carandas including ursolic acid (1), ursolic acid-γ-lactone (2), 27-O-Z-p-coumaroyl ursolic acid (3), 23-hydroxy ursolic acid (4), uvaol (5) and ursolic aldehyde (6). Their structure elucidation was done by modern spectroscopic techniques including 1H-NMR, 13C-NMR and comparison with reported data. All compounds were known, while 2-4 were isolated for the first time from the genus Carissa. Isolated compounds were screened for their cytotoxic via MTT assay and anti-inflammatory potential via luminol-enhanced chem-iluminescence assay. Compounds 3 and 4 showed potent activity against lung cancer cell line (NCI-H460), and 4 showed potent anti-inflammatory activity against reactive oxygen species production from human whole blood phagocytes. Compound 5 displayed good selective cytotoxicity against NCI-H460 and did not provoke cytotoxicity against normal cell line upto 250 µM. Compounds 3-5 were identified as potential anti-cancer drug leads.

Antimicrobial and cytotoxic activities of indole alkaloids and other constituents from the stem barks of Rauvolfia caffra Sond (Apocynaceae).

Twenty indole alkaloids, among which two undescribed ones named rauvolfianoids A (1) and B (2), were isolated from the stem barks of Rauvolfia caffra Sond along with eight other compounds from other biosynthetic pathways. The structures were elucidated by analysis of spectroscopic data, including 1 D and 2 D NMR; absolute configurations of 1 and 2 were determined by CD exciton chirality method. Compounds 1 and 2 were evaluated for antimicrobial and anticancer activities against three bacterial strains (Escherichia coli, Shigella sp and Salmonella sp) and CRC-related opportunistic pathogens. 1 showed moderate antibacterial activity against Salmonella sp with the MIC value of 25 µg/ml, while 2 exhibited weak selective activity against all tested pathogens. In addition, these alkaloids were characterized as weak apoptosis inducers in HCT116 human colon carcinoma cell line.