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

An HPLC-UV method for standardization of the methanol-soluble extracts from tubers of Neorautanenia mitis (A.Rich.) Verdc., Leguminosae, 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 to that in their peels (961 ± 320 µg/g)

ESTABLISHMENT AND VALIDATION OF CHROMATOGRAPHIC METHODS FOR STANDARDIZATION OF NEORAUTANENIA MITIS, A MEDICINAL PLANT USED IN AN ANTI-SCABIES OINTMENT IN RWANDA.

An HPLC-UV method for standardization of the methanol-soluble extracts from tubers of Neorautanenia mitis (A.Rich.) Verdc., Leguminosae, 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 to that in their peels (961 ± 320 µg/g)

Heavy metal removal by combining anaerobic upflow packed bed reactors with water hyacinth ponds

The removal of four selected heavy metals (Cu, Cd, Pb and Zn) has been assessed in an upflow anaerobic packed bed reactor filled with porous volcanic rock as an adsorbent and an attachment surface for bacterial growth. Two different feeding regimes were applied using low (5 mg L-1 of heavy metal each) and high (10 mg L-1 of heavy metal each) strength wastewater. After a start-up and acclimatization period of 44 days, each regime was operated for a period of 10 days with a hydraulic retention time of one day. Good removal efficiencies of at least 86% were achieved for both the low and high strength wastewater. A subsequent water hyacinth pond with a hydraulic retention time of one day removed an additional 61% Cd, 59% Cu, 49% Pb and 42% Zn, showing its importance as a polishing step. The water hyacinth plant in the post-treatment step accumulated heavy metals mainly in the root system. Overall metal removal efficiencies at the outlet of the integrated system were 98% for Cd, 99% for Cu, 98% for Pb and 84% for Zn. Therefore, the integrated system can be used as an alternative treatment system for metal-polluted wastewater, especially in developing countries

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)

ESTABLISHMENT AND VALIDATION OF CHROMATOGRAPHIC METHODS FOR STANDARDIZATION OF NEORAUTANENIA MITIS, A MEDICINAL PLANT USED IN AN ANTI-SCABIES OINTMENT IN RWANDA

An 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 to that in their peels (961 ± 320 µg/g)

The Inhibition of NLRP3 Inflammasome and IL-6 Production by Hibiscus noldeae Baker f. Derived Constituents Provides a Link to Its Anti-Inflammatory Therapeutic Potentials

The activation of NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome and/or its components is associated with the physio-pathogenesis of many respiratory diseases including asthma, COPD (chronic obstructive pulmonary disease), SARS Cov-2 (severe acute respiratory syndrome coronavirus 2), and in several autoimmune diseases. Hibiscus noldeae Baker f. has been widely reported to be traditionally used in the treatment of different ailments, some of which are of inflammatory background such as asthma, wounds, headache, etc. However, the claims have not been supported by evidence at the molecular and functional levels. Here, we report on the bio-guided fractionation of H. noldeae and assessment of the inhibitory properties of some fractions and purified compounds on NLRP3 inflammasome and Interleukin 6 (IL-6). The activation of the NLRP3 inflammasome was determined by detecting the activity of caspase-1 and the production of Interleukin 1β (IL-1β) in Lipopolysaccharide (LPS) and ATP-stimulated Tamm-Horsfall Protein 1 (THP-1) macrophages, while the production of IL-6 was studied in LPS-stimulated RAW264.7 mouse macrophages. It was observed that hexane and ethyl acetate fractions of the crude extract of the aerial parts of H. noldeae, as well as caffeic acid, isoquercetin, and ER2.4 and ER2.7 fractions revealed significant inhibitory effects on Caspase-1 activities, and on IL-1β and IL-6 production. The ER2.4 and ER2.7 fractions downregulated the production of IL-1β and IL-6, in a similar range as the caspase-1 inhibitor AC-YVAD-CHO and the drug Dexamethasone, both used as controls, respectively. Overall, our work does provide the very first scientific based evidence for Hibiscus noldeae anti-inflammatory effects and widespread use by traditional healers in Rwanda for a variety of ailments

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