Pentas longiflora Oliv. (Rubiaceae), a plant used in the treatment of Pityriasis Versicolor in Rwanda: Chemical composition and standardization of leaves and roots

In Rwanda, the roots of Pentas longiflora Oliv. (Rubiaceae) have been used for a long time to treat Pityriasis versicolor. However, many people reported the use of leaves instead of roots. This research was conducted to compare the phytochemical composition and establish chromatographic methods for the standardization of roots and leaves extracts of P. longiflora. During this process, three new pentalongin glycosides (pentalonginoside A, pentalonginoside B, and pentalonginoside C) and two known glycosides of the same type (harounoside and clarinoside), as well as rutin, luteolin-7-rutinoside were isolated from methanol extract of leaves. In addition, pentalongin and psychorubrin, previously isolated from ethylacetate roots extract, were also identified in Pentas longiflora ethylacetate leaves extract. The presence of the antifungal compound pentalongin in leaves may explain the traditional use of leaves in the treatment of Pytiriasis versicolor. Furthermore, harounoside, psychorubrin, and pentalongin were selected as markers for HPLC fingerprints of MeOH extract. The accuracy and risk profile demonstrated the reliability of the validated method. In general, considerable variations of concentration in plant metabolites, including pentalongin, were observed between samples from different sites. The content in pentalongin (expressed as juglone) in collected samples ranged between 1.7 and 70.0 mg/100 g. The highest concentration (70.0 ± 17 mg/100 g) was registered in the cultivated samples from Mukoni. This important variation of pentalongin concentrations according to sampling sites, shows that in order to guarantee equivalent efficacy, finished products with P. longiflora should be standardized based on their pentalongin content

HPLC-UV Method for Standardization of Neorautanenia mitis, an African Plant Used in an Anti-Scabies Ointment

peer reviewedAn HPLC-UV method for standardization of the methanol-soluble extracts from tubers of Neorautanenia mitis (A.Rich.) Verdc., Fabaceae, harvested during different periods and from different sites, is described. The chemical fingerprint was established with six identified markers using LC-ESI (+)-MS/MS, including rotenone; the total error was used as validation criterion, the accuracy and risk profiles demonstrated the reliability of the method. The study verified that the major degradation product of rotenone in methanol is dehydrorotenone. The detection range of rotenone was between 40 and 400 μg/ml. The collected samples contained 868–5732 μg/g of rotenone. The concentrations of rotenone in the wild samples from the Ngoma site (5167 ± 565 μg/g) were higher than those registered in the samples from the other sites. No significant differences were observed among the remaining sampling sites, and most of the rotenone was located in the inner part of the tubers (2165 ± 1051 μg/g) when compared with that in their peels (961 ± 320 μg/g)

Investigation of the Quality of the 12 Most-Used Antibiotics Available in Retail Private Pharmacies in Rwanda

Using poor-quality antibiotics leads to increased risk of the development of microorganism-resistant strains, treatment failure, loss of confidence in health systems, and associated socio-economic impacts. The prevalence of poor-quality antibiotics has been found to be high in some of the Low and Middle-Income Countries (LMICs), but no data were available on the situation in Rwanda. This study was conducted to obtain data and inform health professionals on the quality of the 12 most-used selected antibiotics from private retail pharmacies in Rwanda. The investigation was conducted on 232 batches collected from randomly selected private retail pharmacies in all provinces of Rwanda, and concerned only with visual inspection and assay tests. Visual inspection was performed using a tool adopted by the International Pharmaceutical Federation (FIP) to identify manufacturing defects. An assay test quantified the Active Pharmaceutical Ingredient (API) in each collected batch using high-performance liquid chromatography (HPLC) coupled with an ultraviolet-visible (UV) detector, and the results were reported as the percentage content of the amount of APIs stated on the label. A total of 232 batches were analyzed, manufactured in 10 countries; the main country of manufacture was Kenya, with almost half of the batches (49.6%). The results of the visual inspection did not show the presence of counterfeit/ falsified antibiotics on the Rwandan market in this study but revealed weaknesses in labeling: more than 90% of the analyzed batches of the 12 antibiotics did not present the dosage statement on their label, and the complete list of excipients was missing in more than 20% of the analyzed batches. The assay test using HPLC confirmed the presence of APIs in 100% of the analyzed batches. However, moderate deviations from acceptable ranges of the API content defined by M. M. Nasr & C. M. Stanley in 2006 for erythromycin and the United States Pharmacopoeia 2018 for the other 11 molecules were found. The failure rate to meet the quality requirements in terms of the percentage content of active pharmaceutical ingredients declared on the labels was estimated at 8.2% in total, with 3.9% and 4.3% containing more and less than the amount of APIs stated on the labels respectively. The most-represented antibiotics on the Rwandan market were amoxicillin, co-trimoxazole and cloxacillin. No counterfeit antibiotics were found in this study. However, substandard batches with moderate deviations were found, suggesting that regular quality control of antibiotics is needed in Rwanda

Étude chimiométrique des espèces de genre Strychnos par réseautage moléculaire: exemple de la présence de strychnine

In the last 150 years, different attempts to establish the taxonomy of the Strychnos L. genus (family of Loganiaceae) have been carried out, but the results were not conclusive. The classification that has been most used to this date is from Leeuwenberg which divides the genus into 12 sections. However, in the article from Setubal, R. B. et al (2021), the results led rather to a return to the classification of Duvigneaud. Because of its complexity, the taxonomy of Strychnos is constantly changing. In this context, using new innovative techniques, the various studies of Strychnos carried out within the framework of my project will make it possible to bring new chemical information essential to the elucidation of the taxonomy of the Strychnos genus. This is notably the case of the strychnine study conducted here. During the study of 44 crude extracts of different species (28) and plant parts by LC-MS/MS and by molecular networking, it was found that strychnine is present in species in which it has never been described in the literature. These species are: trunk barks of S. tricalysioides, S. camptoneura, S. congolana, S. boonei, S. densiflora, S. tchibangensis and leaves of S. usambarensis. To confirm this identification, additional analyses by TLC, NMR, HPLC and LC-MS/MS were performed. Moreover, based on MS/MS data, a dereplication software (SIRIUS) was used. In view of the results obtained, it could be confirmed that the quantities of strychnine are very low. Thus, in order to have an estimate of the amount of strychnine contained in these samples, the limit of detection of strychnine using a UV detector was determined. Finally, it was confirmed that strychnine is present in these species, which is a significant contribution to the chemotaxonomic study of Strychnos that still holds many surprises

Exploration approfondie des alcaloïdes de Strychnos par la mise en réseau moléculaire : Découverte de la strychnine dans de nouvelles espèces

peer reviewedDue to their wide variety of traditional uses and promising activities against Plasmodium parasites, plants of the Strychnos genus have been very well studied. Moreover, different attempts to draw an intrageneric taxonomy were made, based on morphological (Duvigneaud) and genetic (Setubal) characters. Moreover, in the Setubal et al. (2021) study, the results concluded that the classification established by Duvigneau is currently the most appropriate. In this context, my research project consists in exploring the chemodiversity of Strychnos alkaloids in order to identify new bioactive metabolites against malaria and cancer, but also to study the chemotaxonomy of Strychnos genus. To achieve these objectives, 44 extracts, from 28 species of Strychnos, were studied by LC-MS/MS and molecular networking. Furthermore, by comparison with MS/MS spectra databases, known and unknown metabolites were annotated. Among the known ones, strychnine was surprisingly detected in seven Strychnos species for the first time, namely in S. tricalysioides, S. camptoneura, S. congolana, S. boonei, S. densiflora, S. tchibangensis and S. usambarensis. The TLC, HPLC, NMR and UPLC-MS/MS analyses allowed to detect the presence of this compound. This novel identification of strychnine, allowed by the sensitivity of the technique used, offers new insights in the chemotaxonomy of the Strychnos genus. The perspectives are, on the one hand, further delineation of indole monoterpene alkaloids distribution in Strychnos spp., in regard to their taxonomic organization and, on the other hand, the identification of original bioactive compounds in this series

L'exploration par réseau moléculaire des alcaloïdes de Strychnos révèle la présence inattendue de strychnine dans sept espèces de Strychnos

peer reviewedIntroduction Plants of the genus Strychnos , which include about 200 species, are used for multiple traditional purposes as hunting poison, for example, and have shown interesting pharmacological properties, especially curarizing and tetanizing, but also against malaria. Many monoterpene indole alkaloids have already been isolated and identified. Among them, there is strychnine, a famous alkaloid that can cause death by asphyxiation. Objective Investigate alkaloidic molecular diversity from Strychnos genus using molecular networking technique and study the Strychnos genus from a chemotaxonomic point of view. Material and methods Twenty-eight different species and different plant parts were ground into powder using a grinder. The methanolic extracts were carried out using a pressurized solvent extraction and the alkaloid extract was performed manually with a separating funnel. The extracts were analyzed by HPLC-ESI(+)-Q/TOF. The data were processed using MZmine 2 software and the molecular network was generated on the GNPS platform. The study of the generated molecular network allowed the detection of various alkaloids. Among these is the famous strychnine which has been detected in 7 new Strychnos species not yet described as strychnine producers. This identification was investigated using orthogonal approaches, namely TLC, NMR, HPLC-UV and UHPLC-ESI(+)-Q/TOF analyses. The LOD by HPLC-UV of strychnine was also determined. Results Further analyses allowed to confirm the presence of strychnine in S. densiflora trunk barks but also to show the presence of strychnine with high probability in the trunk barks of S. camptoneura, S. congolana, S. boonei and S. tchibangensis and in the leaves of S. usambarensis. About the trunk barks of S. tricalyisoides , the probability of a strychnine content remains low. Conclusion This work exemplified the efficiency of molecular networking in identifying known metabolites (major and minor alkaloids) involved in the chemotaxonomic study of plants from Strychnos genus

In Vitro Antiplasmodial and Cytotoxic Activities of Compounds from the Roots of Eriosema montanum Baker f. (Fabaceae).

Malaria remains one of the leading causes of death in sub-Saharan Africa, ranked in the top three infectious diseases in the world. Plants of the Eriosema genus have been reported to be used for the treatment of this disease, but scientific evidence is still missing for some of them. In the present study, the in vitro antiplasmodial activity of the crude extract and compounds from Eriosema montanum Baker f. roots were tested against the 3D7 strain of Plasmodium falciparum and revealed using the SYBR Green, a DNA intercalating compound. The cytotoxicity effect of the compounds on a human cancer cell line (THP-1) was assessed to determine their selectivity index. It was found that the crude extract of the plant displayed a significant antiplasmodial activity with an IC50 (µg/mL) = 17.68 ± 4.030 and a cytotoxic activity with a CC50 (µg/mL) = 101.5 ± 12.6, corresponding to a selective antiplasmodial activity of 5.7. Bioactivity-guided isolation of the major compounds of the roots' crude extract afforded seven compounds, including genistein, genistin and eucomic acid. Under our experimental conditions, using Artemisinin as a positive control, eucomic acid showed the best inhibitory activity against the P. falciparum 3D7, a well-known chloroquine-sensitive strain. The present results provide a referential basis to support the traditional use of Eriosema species in the treatment of malaria.info:eu-repo/semantics/publishe