Strategy for the quality control of herbal preparations made of Sarcocephalus latifolius: Development and validation of a UHPLC-PDA method for quantification of angustoline and strictosamide and chemical profiling using LC-QToF.

INTRODUCTION: Sarcocephalus latifolius is one of the most used plants in West African traditional medicine to treat malaria. OBJECTIVE: The aim is to establish a strategy to control the quality of herbal preparations made from S. latifolius. METHOD: A UHPLC-PDA method was developed for the determination and quantification of the two main bioactive compounds (angustoline and strictosamide) in various parts of the plant. Additionally, an LC-QToF with electrospray ionization method is described for the identification and confirmation of compounds in samples of different parts of the plant. RESULTS: With the UHPLC-PDA method, separation was achieved within 5 min using a C18 column stationary phase at a temperature of 45°C and a gradient system with a mobile phase of water and acetonitrile, both containing 0.1% formic acid. The method was validated for linearity, accuracy, precision (repeatability and intermediate precision), limit of detection (LOD), and limit of quantification (LOQ). The LOD and LOQ of angustoline were found to be 0.3 and 0.8 µg/ml, respectively, and those of strictosamide were found to be 0.1 and 0.3 µg/ml, respectively. Using the LC-QToF method, 90 secondary metabolites, including four isolated compounds from the plant's roots, were identified from leaf, bark, and root samples of S. latifolius. CONCLUSION: This work is the first to propose a strategy to control the quality of herbal preparations made from S. latifolius. The developed method allows the quantification of the main bioactive compounds and the established chemical profile allows to distinguish the plant from any other species.

Daniellia oliveri (Rolfe) Hutch and Dalziel: Antimicrobial Activities, Cytotoxicity Evaluation, and Phytochemical Identification by GC-MS.

During a previous study that identified plants used in traditional medicine in Togo to treat infectious diseases, Daniellia oliveri was specifically reported to treat intertrigo and candidiasis. Consequently, to explore the anti-infective potential of this plant, we investigated the antibacterial and the antifungal activity of the plant's parts, as well as the cytotoxic activities of raw extracts and subsequent fractions, and the chemical composition of the most active fractions. In order to evaluate the antimicrobial activity, MICs were determined using the broth dilution method. Then, the most active fractions were evaluated for cytotoxicity by using normal human cells (MRC-5 cells) via the MTT assay. Finally, the most active and not toxic fractions were phytochemically investigated by GC-MS. Interestingly, all the raw extracts and fractions were active against the bacteria tested, with MICs ranging from 16 µg/mL to 256 µg/mL, while no antifungal activity was observed at 256 µg/mL, the highest tested concentration. Moreover, no toxicity was observed with most of the active fractions. The subsequent chemical investigation of the most interesting fractions led to identifying terpenes, phytosterols, phenolic compounds, and fatty acids as the main compounds. In conclusion, this study demonstrated that D. oliveri possesses valuable antibacterial activities in accordance with traditional use.

Antibacterial activity and cytotoxicity of Pterocarpus erinaceus Poir extracts, fractions and isolated compounds.

ETHNOPHARMACOLOGICAL RELEVANCE: Pterocarpus erinaceus has been chosen based on ethnobotanical surveys carried out in the Tchamba district of the Republic of Togo. AIM OF THE STUDY: Investigation of the antibacterial as well as cytotoxic activities of whole extracts, fractions and compounds isolated from the leaves, trunk bark and roots of Pterocarpus erinaceus. MATERIALS AND METHODS: Bio-guided fractionation of the raw extracts of plant parts and subsequent isolation of compounds from active fractions using normal phase open column chromatography. The broth microdilution method was used to evaluate the antibacterial activity, based on the determination of Minimal Inhibitory Concentrations (MICs) against several bacterial species representative of the most commonly encountered infectious diseases worldwide. The cytotoxicity of the raw extract and the most active fractions on a human non-cancerous cell (namely MRC-5) was estimated with a MTT assay. The chemical structure of the compounds isolated was elucidated using a combination of advanced Nuclear Magnetic Resonance (NMR) and Mass Spectrometry (MS). RESULTS: All extracts and fractions tested have shown good activities against Gram-positive bacteria (including Methicillin-Resistant Staphylococcus aureus, MRSA) and against Pseudomonas aeruginosa with MIC values ranging from 32µg/mL to 256µg/mL. In contrast, extracts were not toxic to MRC-5 cells. Four compounds have been isolated: Compound 1 (friedeline); Compound 2 (2,3 dihydroxypropyloctacosanoate); Compound 3 (a mixture of ß-sitosterol, stigmasterol and campesterol); Compound 4 (ß-sitosteryl-ß-D-glucopyranoside) and shown to be active against some of the bacteria tested. They were active with MIC equal to 4µg/mL against strains of S. aureus (including MRSA). To the best of our knowledge, all of them except friedeline have never been reported in this plant species. CONCLUSION: P. erinaceus is confirmed as a plant harboring promising antibacterial activity with activities against serious human pathogens at very low concentrations. Some of the compounds isolated are also active at concentrations as low as 4µg/mL and therefore, may provide new leads for the development of antibacterial agents.

Turning Waste into Value: Nanosized Natural Plant Materials of Solanum incanum L. and Pterocarpus erinaceus Poir with Promising Antimicrobial Activities.

Numerous plants are known to exhibit considerable biological activities in the fields of medicine and agriculture, yet access to their active ingredients is often complicated, cumbersome and expensive. As a consequence, many plants harbouring potential drugs or green phyto-protectants go largely unnoticed, especially in poorer countries which, at the same time, are in desperate need of antimicrobial agents. As in the case of plants such as the Jericho tomato, Solanum incanum, and the common African tree Pterocarpus erinaceus, nanosizing of original plant materials may provide an interesting alternative to extensive extraction and isolation procedures. Indeed, it is straightforward to obtain considerable amounts of such common, often weed-like plants, and to mill the dried material to more or less uniform particles of microscopic and nanoscopic size. These particles exhibit activity against Steinernema feltiae or Escherichia coli, which is comparable to the ones seen for processed extracts of the same, respective plants. As S. feltiae is used as a model nematode indicative of possible phyto-protective uses in the agricultural arena, these findings also showcase the potential of nanosizing of crude "waste" plant materials for specific practical applications, especially-but not exclusively-in developing countries lacking a more sophisticated industrial infrastructure.