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Rauvolfia vomitoria is a plant acclimatized in Benin - Africa that people use to treat several illnesses such as malaria, cough, typhoid fever, madness, toothache, diabetes, and nausea. The most used organs are leaves, stems, and roots. Thus, the purpose of this work is to contribute to the valorization of R. vomitoria by chemical and biological studies of this plant. Phytochemical analyses of the powder extracts were performed and revealed the presence of alkaloids, tannins, flavonoids, anthocyanins, saponins, terpenes, coumarins, mucilages, reducing compounds, free anthracene derivatives, bound anthracene derivatives (O-glycosides and C-glycosides) with absence of leuco-anthocyanins, quinone derivatives, steroids and cardiotonic glycosids. Evaluation of antisalmonella and antishigella properties of ethanol-water (70:30; V/V) and ethanolic extracts of R. vomitoria leaves showed minimum inhibitory concentrations (MIC) greater than 2000 µg.mL-1 against Salmonella and Shigella strains. The ethanolic extract was the most active by ABTS and FRAP methods and had very good antioxidant activity at scavenging concentration (SC50) equal to 138,62 µg.mL-1 and 185,99 µg.mL-1 respectively

This study was aimed at documenting some pharmacognostic and peptidomic standards on the leaf of Nigerian species of Rauvolfia vomitoria Wennberg (RVM). Using standard methods, the fresh and dried pulverized leaves of R. vomitoria were standardized macroscopically and microscopically, in addition to the physiochemical evaluation and MALDI TOF/TOF-guided peptidomic screening of the aqueous extracts of the leaf. The leaf is simple, elliptical shaped, crenated margin which is acute. The leaf presented a hexagonal shaped epidermal cell on both sides with anomocytic stomata only on the abaxial surface making it hypostomatous while stomata number and index are 15 – 16 – 18 and 24 – 25 – 26, respectively. The transverse section of the leaf through the midrib suggests that the vascular bundles are conjoint, collateral and closed. Moisture content, total ash, acid insoluble ash, water soluble ash, sulphated ash, water soluble and alcohol soluble extractives were as follows; 7.7 ± 1,5, 4.9 ± 0.7, 1.2 ± 0.8, 4.1 ± 0.2, 4.8 ± 0.9, 3.9 ± 0.9, 8.1 ± 1.7w/w%, respectively. Peptidomic analysis revealed the abundant expression of nature-derived knottin-like peptides with a mass range of 3.1 kDa – 3.7 kDa. Knottin peptides have been reported to perform defense roles in host plants; since they are not ubiquitously distributed in planta, their detection in RVM could be useful in the proper identification of the plant and in RVM chemosystematics. Findings from this study has unveiled some important macroscopic, microscopic and physicochemical standards as well as a new peptidomic phytochemical standard helpful in the proper identification in addition to ensuring the efficacy and safety of the leaf of R. vomitoria.

Objective: Study on the non-alkaloid chemical constituents with novel structure and their biological activities from the w-butanol fraction of the leaves of Rauvolfia vomitoria. Methods: The w-butanol fraction of R. vomitoria was separated by silica gel, ODS, and Sephadex LH-20 chromatography column, as well as semi-preparative HPLC to obtain five compounds. Their structures were identified by extensive spectroscopic analysis, including HRESIMS, 1D and 2D NMR, and ECD analysis. All the isolated compounds were evaluated their AChE inhibitory activities by Ellman’s method with slight modification, their vasorelaxant activities against phenylephrine-induced contraction of rat mesenteric arteries, and their inhibitory activity of a-glucosidase employing pNPG as substrate. Results: Two new phenylpropanoids (1-2) along with three known compounds, methyl trans-3,4,5-trimethoxycinnamate (3), methyl cis-3,4,5-trimethoxycinnamate (4), and 3,4,5-trimethoxybenzoic acid methyl ester (5), were isolated from the leaves of R.vomitoria. The five isolated compounds did not show significant tested activity. Conclusion: Chemical investigation of the leaves of R. vomitoria led to the isolation and identification of two new phenylpropanoids (1–2), expanding the study of non-alkaloids in the genus of Rauvolfia and enriching the chemical diversity of this genus.

Searching for new adjuvants of conventional chemotherapeutic approaches against colorectal cancer cells is extremely urgent. In current research, a non-targeted analytical approach was established by combining proton nuclear magnetic resonance spectroscopy with a chemometrics data mining tool to identify chemosensitizing agents from Rauvolfia vomitoria. This approach enabled the identification of potential active constituents in the initial fractionation process and provided their structural information. This strategy was validated by its application to Rauvolfia vomitoria extract exhibiting chemosensitizing activity on 5-fluorouracil against colorectal cancer cells. After the workflow, the biochemometrics analysis showed that at least 15 signals (Variable influence on projection (VIP) > 1) could have contributions in the differentiation of various fractions. Through systematic literature and database searches, we found that the most active fraction (fraction 7) exhibited the highest presence of sabazin-type and armaniline-type alkaloids, which were potential chemosensitizers as previously reported. To validate the results of the strategy, the effect of 5-FU and compounds isolated from fraction seven incubation on HCT-8 and LoVo cell vialibilty were evaluated. These results evidenced that compound β-carboline (3), 1-methyl-β-carboline (4), and lochnerine (6) could enhance the cytotoxicity of 5-fluorouracil against to Colorectal cancer cells. Besides, 21 compounds including two new compounds were isolated from Rauvolfia vomitoria. The experimental results verify the reliability of the method, and this approach provides a new and efficient tool to overcome some of the bottlenecks in natural products drug discovery.

ABSTRACT: Background: Across West Africa, Tabernaemontana crassa Benth., Voacanga africana Stapf., and Rauvolfia vomitoria Azfel. (Apocynaceae) share the same local names, a situation that puts them at risk of unintended adulteration. The study aimed at setting macro- and micromorphological standards, phytochemical and physicochemical standards for the unequivocal differentiation of the three plants. Methods: Macro- and micro-morphological features, quantitative microscopy, soluble extractives, pH, ash values, fluorescence, phytochemical and thin layer chromatographic profiles of leaves, stem, and roots of the three plants were determined using standard methods. Results: The whole leaves showed that all three plants possessed opposite petiolate leaves. The leaves of R. vomitoria and V. africana were elliptic in /shape, whereas T. crassa leaves were oblanceolate. Further differences in stomata arrangement, epidermal cells, histological features of their midribs, surface data determinations, phytochemical and physicochemical profiles of the leaves, stem bark and roots present useful data for clearly distinguishing between the three species. Conclusion: The determined parameters of the leaves, stems, and roots of T. crassa, V. africana, and R. vomitoria support the unequivocal identification of the individual plants. This is important for correct sourcing of these plants for herbal product manufacturers, regulators, and researchers.