Exploration by molecular networking of Strychnos alkaloids reveals the unexpected occurrence of strychnine in seven Strychnos species.

INTRODUCTION: Plants of the Strychnos genus, 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.

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.

In Vitro Antilipidic and Antithrombotic Activities of Plectranthus glandulosus (Lamiaceae) Leaves Extracts and Fractions.

OBJECTIVE: The present study investigated the effect of the leaves extracts and fractions of Plectranthus glandulosus on the inhibition of pancreatic lipase, cholesterol esterase, adipocytes lipid uptake, and antithrombotic activity which may be important in atherosclerosis development. METHODS: Aqueous, ethanolic, and hydroethanolic extracts of Plactranthus glandulosus were prepared by maceration. The hydroethanolic extract was fractionated into n-hexane, ethylacetate, and n-butanol fractions and their inhibition of pancreatic lipase, cholesterol esterase, adipocytes lipid uptake, and antithrombotic activities measured. Liquid chromatography-high resolution mass spectrometry (LC-HRMS) analysis was carried out to determine phytochemical constituents present in the extracts. RESULTS: The standard orlistat exhibited a higher inhibitory activity on pancreatic lipase and cholesterol esterase (16.31 µg/mL and 15.75 µg/mL, respectively) compared to ethyl acetate fraction (IC50, 17.70 µg/mL and IC50, 24.8 µg/mL, respectively). Among crude extract, hydroethanolic extract showed a better inhibition against pancreatic lipase (IC50, 21.06 µg/mL) and cholesterol esterase (IC50, 25.14 µg/mL) though not comparable to the effect of orlistat. The best lipid uptake inhibition was observed in the hydroethanolic extract (IC50, 45.42 µg/mL) followed by the ethyl acetate fraction (IC50, 47.77 µg/mL). A better antithrombolytic activity was exhibited by the ethyl acetate fraction at all concentrations (50-800 µ/mL), while hydroethanolic extract exhibited the best activity among crude extract. However, these were not comparable to the standard aspirin. The LC-HRMS analysis revealed the presence of 7-O-methyl luteolin 5-O-ß-D-glucopyranoside, chrysoeriol 5-O-ß-D-glucopyranoside, 5,7-dihydroxy-3,2',4'-trimethoxyflavone, and plectranmicin as major compounds in both hydroethanolic extract and ethyl acetate fraction. CONCLUSION: Thus, our finding supports the traditional use of this plant, which might provide a potential source for future antiatherosclerotic drug discovery.

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.

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.