Beninese Plant Extracts with Antiplasmodial Activity Select New Allele Variants Msp1 and Msp2 in Plasmodium falciparum.

Background: Natural medicinal products are commonly used as a remedy against malaria infections in African populations and have become a major source of information for the screening of new and more effective antiplasmodial molecules. Therefore, in vitro studies are needed to validate the efficacy of these medicinal products and to explore the potential effects of such drugs on the genetic diversity of Plasmodium falciparum. The current study has investigated the impact of some Beninese plant extracts with antiplasmodial activity on the genetic diversity of P. falciparum. Method: Five (5) ethanolic plant extracts (Dissotis rotundifolia, Ehretia cymosa Thonn, Hibiscus surattensis L., Cola millenii K. Shum, and Costus afer Ker Gawl) and a compound extracted from Ehretia cymosa Thonn (encoded CpE2) were tested against asexual stage parasites of a culture-adapted strain of P. falciparum. Subsequently, the P. falciparum Msp1 and Msp2 markers were genotyped, and the number of allelic variants and the multiplicity of infection (MOI) were compared between drug-exposed and unexposed parasites. Results: All plant extracts have shown inhibitory activity against asexual P. falciparum and selected new allelic variants of the Msp1 and Msp2 genes compared to unexposed parasites. The newly selected allelic variants were K1_100bp and RO33_300bp of the Msp1 gene and FC27_150bp, FC27_300bp, FC27_400bp, and FC27_600bp of the Msp2 gene. However, there was no significant difference in MOI between drug-exposed and unexposed parasites. Conclusion: Our study highlights a source for the selection of new Msp1 and Msp2 alleles after exposure to antimalarial drugs. These findings pave the way for further studies investigating the true roles of these newly selected alleles in P. falciparum.

Voltammetric techniques for low-cost on-site routine analysis of thymol in the medicinal plant Ocimum gratissimum.

The composition of essential oils varies according to culture conditions and climate, which induces a need for simple and inexpensive characterization methods close to the place of extraction. This appears particularly important for developing countries. Herein, we develop an analytical strategy to determine the thymol content in Ocimum Gratissimum, a medicinal plant from Benin. The protocol is based on electrochemical techniques (cyclic and square wave voltammetry) implemented with a low cost potentiostat. Thymol is a phenol derivative and was directly oxidized at the electrode surface. We had to resort to submillimolar concentrations (25-300 µM) in order to minimize production of phenol oligomers that passivate the electrode. We worked first on two essential oils and realized that in one of them the thymol concentration was below our detection method. These results were confirmed by gas chromatography - mass spectrometry. Furthermore, we optimized the detection protocol to analyze an infusion made directly from the leaves of the plant. Finally, we studied whether the cost of the electrochemical cell may also be minimized by using pencil lead as working and counter electrodes.

Negative association between ascaris lumbricoides seropositivity and Covid-19 severity: insights from a study in Benin.

Introduction: The COVID-19 pandemic has had devastating effects worldwide, but the trajectory of the pandemic has been milder in Low-and-Middle-Income Countries (LMICs), including those in Africa. Co-infection with helminths, such as Ascaris lumbricoides, has been suggested as a possible factor contributing to the reduced severity observed in these regions. Methods: The present study investigated the association between Ascaris-specific antibody levels and COVID-19 severity in 276 SARS-CoV-2-infected individuals in Benin. Participants were categorized into asymptomatic (n=100), mild (n=150), and severe (n=26) groups based on clinical disease severity. Sera were collected and analyzed using ELISA to measure Ascaris and SARS-CoV-2-specific antibodies, while Luminex was used to assess cytokines and SARS-CoV-2-specific neutralizing antibody expression. Results and discussion: The results demonstrated that asymptomatic SARS-CoV-2 seropositive individuals expressed, on average, 1.7 and 2.2-times higher levels of Ascaris antibodies compared to individuals with mild and severe COVID-19, respectively. This finding suggests an inverse correlation between Ascaris antibody levels and COVID-19 severity. Notably, logistic regression analysis showed that Ascaris seropositivity was significantly associated with a reduced risk of severe COVID-19 (OR = 0.277, p = 0.021). Interestingly, COVID-19 patients with comorbidities such as type 2 diabetes and high blood pressure showed lower expression of Ascaris antibodies. Strikingly, no correlation was observed between Ascaris antibody levels and SARS-CoV-2-specific neutralizing antibodies. On the other hand, individuals seronegative for Ascaris displayed significantly higher levels of systemic pro-inflammatory markers compared to seropositive individuals. These findings suggest that higher expression of Ascaris antibodies is associated with asymptomatic SARS-CoV-2 infections and may contribute to the reduction of the risk to develop severe COVID-19. The beneficial effect of Ascaris seropositivity on COVID-19 outcomes in Benin may be attributed to a decrease in comorbidities and pro-inflammatory markers. These observations provide valuable insights into the milder COVID-19 trajectory observed in Africa and may have implications for future therapeutic strategies.

Anti-Salmonella activity of plant species in the Benin republic: Artemisia afra and Detarium senegalense with promising in vitro and in vivo activities.

Non-typhoidal invasive Salmonella (NTiS) diseases are one of the most important zoonoses in the world. This study explored the antipathogenic potential of twenty-four plants used in Benin folk medicine against NTiS diseases. The in vitro antibacterial and antibiofilm activities of ethanolic plant extracts were screened against clinical resistant isolates and ATCC reference strains of Salmonella. Salmonella enterica serovar Typhimurium-infected rat model was used to examine the in vivo antibacterial potential of plant extracts. Of the 24 plants, 18 plants exhibited antibacterial activity against Salmonella enterica strains with minimum inhibitory concentrations (MICs) ranging from 0.156 to 1.25 mg/mL. Anacardium occidentale, Artemisia afra, Detarium microcarpum, Detarium senegalense, and Leucaena leucocephala were the most active plant species. Extracts from A. afra, D. microcarpum, and D. senegalense showed biofilm inhibition greater than 50% against Salmonella clinical isolates. In the rat model of infection, A. afra and D. senegalense extracts were found to have an effective dose of less than 100 mg/kg and to stop the salmonellosis after 10 days of treatment. Additionally, these extracts did not produce any toxic effects in the treated animals. These results indicate clear evidence supporting the anti-Salmonella activity of A. afra and D. senegalense. Further studies are now needed to isolate bioactive compounds and to ensure the safety of these plant species.

The Metabolomic study of Calotropis procera Ait. from Burkina Faso, based on chemical functional groups profiling using FTIR.

Background C. procera is an important wild medicinal plant used in different area of Burkina Faso for the neuropsychiatric disorders treatment. It was reported to possess many pharmacological properties because of its phytochemical diversity. This study was carried out to identify possible specific chemical characteristics form C. procera leaves and root-bark samples, harvested in two regions of Burkina Faso, for a better selective use of specimens in traditional medicine. Methods Plant materials (leaves and root-bark) were collected from five sites in each region. Samples powders and extracts were mixed with potassium bromide for the Fourier Transform Infrared Spectroscopy (FTIR) analysis. A multivariate data analysis was performed to highlight differences in the FTIR spectral profile of samples. Therefore, phytochemical contents such as phenolics, flavonoids and terpenoids were evaluated with aqueous and methanolic extracts, using UV/visible light spectrophotometer method. Results Results of principal component analysis (PCA) showed a significant difference between leaves and root-bark spectral profile, independently to the region of collection. These profiles possess characteristic signals which could be exploited as biomarkers for plant organ discrimination. The phytochemical contents evaluation showed that C. procera leaves contain more significant phenolics, and root-bark possess more terpenoid compounds. This study of C. procera Ait. based on FTIR spectral characteristic and phytochemical content, suggest that terpenoids, notably cardenolide-type could be a good biomarkers for C. procera samples characterization and to explain root-bark therapeutic potential.

MooSciTIC: Training of trainers in West African research and higher education.

The MooSciTIC project is a capacity-building initiative targeting West African research scientists and higher education teachers. The project aimed to improve the self-reliance of researchers and upgrade research practices by providing on-site summer schools on trans-disciplinary topics such as scientific writing, communication, and integrity. Here, we explain how this program was designed and implemented and share the positive responses from our trainees, hoping to inspire similar initiatives.

Evidence of Immunosuppressive and Th2 Immune Polarizing Effects of Antidiabetic Momordica charantia Fruit Juice.

The mechanism of action of the antidiabetic capacity of Momordica charantia is still under investigation. Here, we assessed phytochemical compositions, antioxidant activity, and effects of total and filtered fruit and leafy stem juices of Momordica charantia on human T cell proliferation and differentiation through quantification of Th1/Th2 cytokines. In the absence of stimulation, total fruit and leafy stem juices induced significant T cell proliferation. Under PHA stimulation, both juices potentiated plant-induced T cell proliferation. However, the filtered fruit and leafy stem juices significantly inhibited PHA-stimulated T cell proliferation, while neither juice influenced T cell proliferation. Moreover, total and filtered fruit juice increased IL-4 secretion, while total and filtered leafy stem juice enhanced IFN-γ production. Phytochemical screening revealed the presence of tannins, flavonoids, anthocyans, steroids, and triterpenoids in both juices. Alkaloids, quinone derivatives, cardenolides, and cyanogenic derivatives were undetectable. The saponins present in total juices were undetectable after filtration. Moreover, both juices had appreciable antioxidant capacity. Our study supports the type 1 antidiabetic effect of filtered fruit juice of M. charantia which may be related to its immunosuppressive and T-helper 2 cell inducing capacities. Due to their immune-stimulatory activities and their ability to increase T-helper 1 cell cytokines, total fruit and leafy stem juices may serve in the treatment of immunodeficiency and certain infections.

Acthaside: a new chromone derivative from Acacia ataxacantha and its biological activities.

BACKGROUND: Acacia ataxacantha (Fabaceae), used in traditional medicine grows in the South-West of Bénin. Ethyl acetate extract of the barks of this species was previously reported to display various bioactivities, including antibacterial, antifungal and antioxidant activities. In the present study, we investigate the antimicrobial and antioxidant activities of compound isolated from ethyl acetate extract of Acacia ataxacantha. METHODS: Purification, isolation and structural identification of isolated compound were done using various chromatographic and spectroscopic methods. Antimicrobial activity was investigated using a two-fold serial microdilution method. The inhibitory potency of isolated compound was evaluated by kinetic experiments. The antioxidant activity was also determined using 2, 2-diphenyl-1-picrylhydrazyl. RESULTS: The isolated compound was identified as 7-hydroxy-2-methyl-6-[ß-galactopyranosyl-propyl]-4H-chromen-4-one. As far as we know, this compound, named "acthaside", reported for the first time, was active against all tested microorganisms with minimal inhibitory concentration ranging from 25 to 50 µg/ml. At 50 µl/ml, no growth was observed in almost all tested microbial after 24 h of exposure. The isolated compound had significant antioxidant activity with an IC50 value of 3.61 ± 0.12 µg/ml compared to quercetin (IC50 1.04 ± 0.01 µg/ml). CONCLUSION: The present work demonstrates that the new chromen derivative isolated from A. ataxacantha may help treat bacterial and yeast infections. However, further studies are required to clarify the mechanism of action of this compound.

Triterpenoids from Acacia ataxacantha DC: antimicrobial and antioxidant activities.

BACKGROUND: Acacia ataxacantha is a medicinal specie used extensively in traditional medicine of Benin republic to treat infectious diseases. Our previous study showed interesting antibacterial and antifungal activities against six strains of bacteria and six strains of fungi. The aim of this study was to investigate the antimicrobial and antioxidant activities of compounds isolated from A. ataxacantha. METHODS: Chromatographic and spectroscopic methods were used to isolate and identify three compounds (1-3) from the bark of A. ataxacantha. Phytochemical investigation of A. ataxacantha (Fabaceae) led to the isolation of three triterpenoids (1-3). The structure of isolated compounds was established by differents spectroscopic methods such as UV, (1)H NMR, (13)C NMR, 2D NMR and Mass. All isolated compounds were tested for antimicrobial activity using agar disc-diffusion and microdilution methods. The radical scavenging activity of isolated compounds was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. RESULTS: Phytochemical investigation led to the isolation and identification of lupeol (1), betulinic acid (2) and betulinic acid-3-trans-caffeate (3). Moderate antimicrobial activity was obtained with compound 3 against methicillin-resitant Staphylococcus aureus, Enterococcus feacalis and Pseudomonas aeruginosa with MIC value of 25 µg/ml and Staphylococcus aureus (MIC of 50 µg/ml). Compounds 3 was more active against Staphylococcus epidermidis and Candida albicans with a MIC value of 12.5 µg/ml in boths cases. Compounds 3 had also interesting antioxidant activity with an IC50 of 3.57 µg/ml compared to quercetin (1.04 µg/ml). CONCLUSION: The overall results of this study provide evidence that the compound 3, isolated from A. ataxacantha, exhibit antimicrobial activity against Gram-positive and Gram-negative bacteria and yeast, especially against C. albicans.

Antimicrobial, antioxidant, toxicity and phytochemical assessment of extracts from Acmella uliginosa, a leafy-vegetable consumed in Bénin, West Africa.

BACKGROUND: Acmella uliginosa (Asteraceae) is a flowering plant whose leaves are consumed as a vegetable in Benin. They are also traditionally used as an antibiotic in the treatment of infectious diseases. To evaluate the therapeutic potential and toxicity effect of this leafy-vegetable, the antibacterial, antifungal, antioxidant activities and, toxicity and phytochemical constituents were investigated. METHODS: Dichloromethane, methanol and aqueous extracts of Acmella uliginosa were evaluated for their antimicrobial activity against six bacterial and six fungi strains. Antibacterial and antifungal activities were investigated by microdilution method and agar diffusion method respectively. Antioxidant activity was assessed using the 2,2-diphenyl-1-picryl-hydrazyl assay and phytochemical screening was carried out using standard procedures. Finally, oral acute toxicity at a dose of 2000 mg/kg was done according to the Organization for Economic Co-operation and Development guideline n° 423. RESULTS: The antibacterial activity was broad spectrum, inhibiting both Gram-positive and Gram-negative bacteria. The minimum inhibitory concentration ranged from 0.625 to 5 mg/ml. The antifungal evaluation show that all the extracts inhibited mycelial growth and sporulation of fungi with percentages of inhibition ranging from 9.39 to 75.67% and 22.04 to 99.77%, respectively. In DPPH radical scavenging assay, the effect on reducing free radicals increased in a dose dependent manner. The percentage of inhibition of DPPH ranged from 0.94 to 73.07%. Phytochemical screening revealed the presence of coumarin, flavonoid, naphtoquinone, anthracene derivative, saponin, lignan, triterpene and tannin. The dichloromethane and methanol extracts showed the best biological activities; they were also shown as the best extraction solvents of phytochemicals. In the acute toxicity evaluation, all animals were physically active and no deaths of rats were observed during the test. However, the aqueous extract promoted biochemical, hematological and histopathological alterations of treated rats at 2000 mg/kg body weight. CONCLUSION: A. uliginosa extracts contains antimicrobial, antioxidant agents and was not lethal for rats when ingested. However, according to the results obtained for biochemical, hematological, and histopathological analysis, caution is required regarding its consumption.

In vitro antileishmanial, antiplasmodial and cytotoxic activities of a new ventiloquinone and five known triterpenes from Parinari excelsa.

CONTEXT: Parinari excelsa Sabine (Chrysobalanaceae) is an indigenous tree from West and Eastern Africa. This tree is used in Ivory Coast as an antimalaria remedy. OBJECTIVE: The in vitro antiplasmodial and antileishmanial activities of the stem bark, the leaf and the major compounds from the stem bark were investigated. MATERIALS AND METHODS: The leaves and stem bark from P. excelsa were separately collected, air-dried and powdered. Two extracts (methylene chloride and methanol) were realized for both powders. Every extract was tested for its antiplasmodial and antileishmanial activities. Only the stem bark crude extracts were fractionated by column chromatography and their major components were analyzed by NMR, HRESIMS and IR methods. The compounds were tested for their antiplasmodial and antileishmanial activities. RESULTS: The comparison of the IC(50) values of the crude extracts were in this order: 3.41 (IC(50) of PeBMc) <4.10 (IC(50) of PeBMc) <4.42 (IC(50) of PeLMe) against P. falciparum and 5.19 (IC(50) of PeBMc) <12.32 (IC(50) of PeBMe) <19.33 (IC(50) of PeLMc) <32.37 (IC(50) of PeLMe) against L. donovani. The stem bark crude extracts were the most active against both parasites. Their fractionation leaded to a new ventiloquinone, five triterpenes and one chlorogenic acid. All these compounds were isolated for the first time from P. excelsa. High activities were observed with (3ß)-3-hydroxyolean-12-en-28-oic acid (IC(50) = 8.2 µM) and 3ß-hydroxyolean-5,12-dien-28-oic acid (IC(50) = 7.7 µM) against L. donovani. With the antiplasmodial activity, the best activity was observed with 16ß-hydroxylupane-1,20(29)-dien-3-one (IC(50) = 28.3 µM). DISCUSSION AND CONCLUSION: These findings demonstrated that the constituents of P. excelsa stem bark have in vitro antiplasmodial and antileishmanial activities.

Evaluation of ethnobotanically selected Benin medicinal plants for their in vitro antiplasmodial activity.

Twenty extracts from nine Benin medicinal plants, traditionally used to treat malaria, were screened for in vitro antiplasmodial activity towards Plasmodium falciparum K1 chloroquine resistant and 3D7 chloroquine sensitive strains. All plants showed antiplasmodial activity below 10 microg/ml. Nine extracts exhibited IC50 values below 5 microg/ml towards one or both of the two strains. The most active extract towards the sensitive 3D7 strain was the methanolic extract of Croton lobatus aerial part, with an IC50 value of 0.38 microg/ml. The best inhibition of the growth of Plasmodium falciparum resistant K1 strain was observed with the methylene chloride extract of Hybanthus enneaspermus and with the methanolic extract of Croton lobatus roots (IC50=2.57 and 2.80 microg/ml, respectively).