Background Besides feeding on blood, females of the malaria vector Anopheles gambiae sensu lato readily feed on natural sources of plant sugars. The impact of toxic secondary phytochemicals contained in plant-derived sugars on mosquito physiology and the development of Plasmodium parasites remains elusive. The focus of this study was to explore the influence of the alkaloid ricinine, found in the nectar of the castor bean Ricinus communis, on the ability of mosquitoes to transmit Plasmodium falciparum. Methods Females of Anopheles gambiae and its sibling species Anopheles coluzzii were exposed to ricinine through sugar feeding assays to assess the effect of this phytochemical on mosquito survival, level of P. falciparum infection and growth rate of the parasite. Results Ricinine induced a significant reduction in the longevity of both Anopheles species. Ricinine caused acceleration in the parasite growth rate with an earlier invasion of the salivary glands in both species. At a concentration of 0.04 g l−1 in An. coluzzii, ricinine had no effect on mosquito infection, while 0.08 g l−1 ricinine-5% glucose solution induced a 14% increase in An. gambiae infection rate. Conclusions Overall, our findings reveal that consumption of certain nectar phytochemicals can have unexpected and contrasting effects on key phenotypic traits that govern the intensity of malaria transmission. Further studies will be required before concluding on the putative role of ricinine as a novel control agent, including the development of ricinine-based toxic and transmission-blocking sugar baits. Testing other secondary phytochemicals in plant nectar will provide a broader understanding of the impact which plants can have on the transmission of vector-borne diseases. Graphical abstract

Up to now, the control of malaria remains a challenge. The World Health Organization (WHO) recommends the use of artemisinin-based combination therapies (ACTs) for uncomplicated malaria treatment. Despite this guideline, many people in Burkina Faso use herbal medicine as primary treatment against malaria. The aim of this study was to assess the in vivo activity of Guiera senegalensis J. F. Gmel and Bauhinia rufescens Lam. leaves extracts against Plasmodium berghei ANKA. A four-day treatment of leaves decoction of each plant was administrated orally to 7 groups of six NMRI (Naval Medical Research Institute) mice infected with Plasmodium berghei ANKA strain. The control group received distilled water as treatment while the treated groups each received daily 100, 250, and 500 mg extract/kg body weight. Thin blood smears were performed on day five and the percentage of reduction of parasitaemia was determined compared to the control. The percentages of reduction of the parasitaemia at the doses of 100, 250, and 500 mg extract/kg body weight were, respectively, 57.5%, 35.9%, and 44.9% for Guiera senegalensis and 50.6%, 22.2%, and 25.7% for Bauhinia rufescens. Our findings on antiplasmodial activity of these two plants justify the traditional use by local populations against malaria. Thus, the isolation of the active compounds from these two plants is suggested for possible antimalarial candidate drugs.

Inflammation is the supreme biological response to illness. In the Hauts-Bassins region, in traditional medicine, all parts of Cassia sieberiana and Piliostigma thonningii are used to treat hepatitis and inflammation. The aim of this study was to evaluate the in vitro antioxidant and anti-inflammatory activities of their aqueous extracts. High performance liquid chromatography with photodiode array (HPLC-DAD) and ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-MS/MS) analyses highlighted the presence of polyphenols and flavonoids. Antioxidant and anti-inflammatory activities were measured by various methods such as DPPH (2,2-diphenyl-1-picrylhydrazyl), ABTS 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), TAC (total antioxidant capacity), anti-protease, anti-lipoxygenase, and membrane stabilization. The best antioxidant activity was observed in the bark (DPPH: IC50 = 13.45 ± 0.10µg/mL) and roots (TAC = 29.68 ± 1.48 mgAAE/g DW) of Piliostigma thonningii and in the roots (ABTS: IC50 = 1.83 ± 0.34 µg/mL) of Cassia sieberiana. The best anti-inflammatory activity was observed in the bark (anti-lipoxygenase: IC50 = 13.04 ± 1.99 µg/mL) and leaves (anti-proteases: IC50 = 75.74 ± 1.07 µg/mL, membrane stabilization: IC50 = 48.32 ± 6.39 µg/mL) of Cassia sieberiana. Total polyphenols (ABTS: r = −0.679, TAC: r = 0.960) and condensed tannins (ABTS: r = −0.702, TAC: r = 0.701) were strongly correlated with antioxidant activity. Total flavonoids (anti-proteases: r = −0.729), condensed tannins (anti-proteases: r = 0.698), and vitamin C (anti-proteases: r = −0.953) were strongly correlated with anti-inflammatory activity. Total polyphenols, flavonoids, condensed tannins, and vitamin C could contribute to the antioxidant and anti-inflammatory activities of the two studied plants. These results could validate the traditional use of these plants to treat various inflammatory diseases.

We acknowledge the financial support from UMOEA PACER-2 programme (Programme d'appui et de développement des Centres d'excellence régionaux).

This study aimed to list the medicinal plants used as an appetite suppressant in Hauts-Bassins areas of Burkina Faso. An ethnobotanical survey was undertaken from September to November 2021 using a semi-structured questionnaire. To determine well-known families and species, some indices such as Family Importance Value (FIV) and Relative Frequency of Citation (RFC) were calculated respectively. Sixty-seven traditional healers (41 men and 26 women) have been interviewed. The age group from 41 to 60 years old was more represented (47.76%). Fifty-eight (58) plant species belonging to 29 families and 53 genera were recorded to have appetite suppressant properties. Fabaceae family (25%) was the most mentioned followed by Combretaceae (12%). The most mentioned species were Guierasenegalensis (7.64%), Parkiabiglobosa (6.18%), Annona senegalensis and Gardenia erubescens (5.35% for both). Leaves and fruits had the highest frequencies of use with 41% and 25% respectively. The decoction (49.62%) was the main preparation method. The oral route was the only mode of drug administration. These results would contribute to strengthening the database on the medicinal plants used as an appetite suppressant by the traditional healers in Burkina Faso.

The aim of the present study was to investigate the polyphenolic profile and the anti-inflammatory and anti-nociceptive activities of four traditionally used medicinal plants from Burkina Faso: Parkia biglobosa, Detarium microcarpum, Vitellaria paradoxa and Sclerocarya birrea. The analysis of the main phenolic compounds was performed by the HPLC-UV-MS method. The anti-inflammatory effect of the aqueous bark extracts was investigated by the λ-carrageenan-induced rat paw edema test. The anti-nociceptive activity was evaluated by the Randall–Selitto test under inflammatory conditions. Seven phenolic acids (gallic, protocatechuic, gentisic, vanillic, p-coumaric, ferulic, and syringic acids), and three flavonoids (catechin, epicatechin, and quercitrin) were identified in the plant samples. High contents of gallic acid were determined in the D. microcarpum, P. biglobosa and S. birrea extracts (190–300 mg/100 g), and V. paradoxa extract was the richest in epicatechin (173.86 mg/100 g). The λ-carrageenan-induced inflammation was significantly reduced (p < 0.001) by the P. biglobosa and D. microcarpum extracts (400 mg/kg p.o.). Under the inflammatory conditions, a significant anti-nociceptive activity (p < 0.001) was obtained after 2–3 h from the induction of inflammation. The effects of the tested extracts could be related to the presence of polyphenols and could be useful in the management of certain inflammatory diseases.

The dichloromethane/methanol leaf extract of Cassia alata had a good to moderate in vitro and in vivo antiplasmodial activity and was found to have low toxicity at high doses in tested animals.

Scientific information on antioxidant properties and phenolic content of Nauclea latifolia used in ethnoveterinary medicine in Burkina Faso are limited. Therefore, the quantification of the antioxidant activity of different parts of this specie remains an interesting and useful task, particularly for finding new sources for natural antioxidants. The aim of this study was to evaluate the antioxidant activity and total polyphenols of Nauclea latifolia Smith (Rubiaceae) acetonic fractions from Burkina Faso. n-hexane, dichloromethane, ethyl acetate and n-butanol fractions of leaves, barks and root barks were tested for their antioxidant activities using DPPH, ABTS and FRAP methods. Folin-Ciocalteu and AlCl3 reagents were used to quantify the polyphenols. n-butanol fraction of barks (58.16 ± 0.76 mg GAE/100 mg), dichloromethane fraction of barks (51.13 ± 0.99; 26.14 mg GAE/100 mg) have presented the best total phenolic contents while the best total flavonoid contents were found in n-butanol fraction of leaves and n-hexane fraction of leaves with 4.85 ± 0.14 mg EQ/100mg and 2.92 ± 0.13 mg EQ/100mg, respectively. It was observed that n-hexane fraction of leaves was scavenge more DPPH free radicals with a value of 1011.98± 17,01 µmol EAA/g. That of n-butanol fractions of barks was showed the best ferric reduction power (3056.37 ± 96.66 µmol EAA/g) and the highest ABTS cation radicals scavenging capacity (7031.52 ± 254.98 µmol EAA/g). Nevertheless, this work encourages investigations on Burkina Faso plant species used in the ethnoveterinary medicine as sources of antioxidants. Keywords: Fraction; Ouagadougou; Barks, Total Polyphenols Contents; Radicals.