Malaria in Guinean Rural Areas: Prevalence, Management, and Ethnotherapeutic Investigations in Dionfo, Sub-Prefecture of Labe.

As part of a validation program of antimalarial traditional recipes, an ethnotherapeutic approach was applied in Dionfo, a meso-endemic Guinean rural area where conventional health facilities are insufficient. A prevalence investigation indicated a malarial burden of 4.26%. Ethnomedical and ethnobotanical surveys led to a collection of 63 plant species used against malaria from which Terminalia albida (Combretaceae) was one of the most cited. Ethnotherapeutic evaluation of a remedy based on T. albida was applied to 9 voluntary patients suffering from uncomplicated malaria. Treatment of 7 to 14 days led to an improvement of clinical symptoms and a complete parasite clearance achievement of 8/9 patients without side effects. In addition to antiplasmodial activity in vitro and in vivo previously described, this study indicates an efficacy to support the antimalarial traditional use of T. albida, which could constitute a first-aid treatment when access to other medicines is delayed in the Dionfo community. Ethnotherapeutical investigation could be a valuable approach to guide subsequent investigations on traditional remedies.

Variation in chemical composition and antimalarial activities of two samples of Terminalia albida collected from separate sites in Guinea.

BACKGROUND: The disparity of harvesting locations can influence the chemical composition of a plant species, which could affect its quality and bioactivity. Terminalia albida is widely used in traditional Guinean medicine whose activity against malaria has been validated in vitro and in murine models. The present work investigated the antimalarial properties and chemical composition of two samples of T. albida collected from different locations in Guinea. METHOD: T. albida samples were collected in different locations in Guinea, in Dubréka prefecture (West maritime Guinea) and in Kankan prefecture (eastern Guinea). The identity of the samples was confirmed by molecular analysis. In vitro antiplasmodial activity of the two extracts was determined against the chloroquine resistant strain PfK1. In vivo, extracts (100 mg/kg) were tested in two experimental murine models, respectively infected with P. chabaudi chabaudi and P. berghei ANKA. The chemical composition of the two samples was assessed by ultra-high-performance liquid chromatography coupled to high resolution mass spectrometry. RESULTS: In vitro, the Dubréka sample (TaD) was more active with an IC50 of 1.5 µg/mL versus 8.5 µg/mL for the extract from Kankan (TaK). In vivo, the antiparasitic effect of TaD was substantial with 56% of parasite inhibition at Day 10 post-infection in P. chabaudi infection and 61% at Day 8 in P. berghei model, compared to 14 and 19% inhibition respectively for the treatment with TaK. In addition, treatment with TaD further improved the survival of P. berghei infected-mice by 50% at Day 20, while the mortality rate of mice treated with Tak was similar to the untreated group. The LC/MS analysis of the two extracts identified 38 compounds, 15 of which were common to both samples while 9 and 14 other compounds were unique to TaD and TaK respectively. CONCLUSION: This study highlights the variability in the chemical composition of the species T. albida when collected in different geographical locations. These chemical disparities were associated with variable antimalarial effects. From a public health perspective, these results underline the importance of defining chemical fingerprints related to botanical species identification and to biological activity, for the plants most commonly used in traditional medicine.

Bioassay-guided isolation of antiplasmodial and antimicrobial constituents from the roots of Terminalia albida.

ETHNOPHARMACOLOGICAL RELEVANCE: Terminalia albida (Combretaceae), widely used in Guinean traditional medicine, showed promising activity against Plasmodium falciparum and Candida albicans in previous studies. Bioassay-guided fractionation was carried out in order to isolate the compounds responsible for these activities. MATERIALS AND METHODS: Fractionation and isolation were performed by flash chromatography, followed by semi-preparative HPLC-DAD-MS. The structural elucidation of the isolated compounds was carried out by 1D and 2D NMR as well as HR-ESI-MS. Isolated compounds were evaluated against Plasmodium falciparum, Candida albicans, Staphylococcus aureus and Escherichia coli, and their cytotoxicity against MRC-5 cells was determined. RESULTS: Bioassay-guided fractionation of Terminalia albida root resulted in the isolation of 14 compounds (1-14), and their antimicrobial properties were evaluated. Pantolactone (1) (IC50 0.60 ± 0.03 µM) demonstrated significant activity against P. falciparum. Other compounds, including 3,4,3'-tri-O-methyl-ellagic acid (3), the triterpenes arjunolic acid (5), arjungenin (6), arjunic acid (7) and arjunglucoside II (10), and the phenol glycoside calophymembranside-B (14), were less active and showed IC50 values in the range 5-15 µM. None of the tested compound showed antibacterial or antifungal activity. CONCLUSION: These results may explain at least in part the activity of the root extract of T. albida against P. falciparum.

Antimicrobial investigation of ethnobotanically selected guinean plant species.

ETHNOPHARMACOLOGICAL RELEVANCE: In Guinea, medicinal plants play an important role in the management of infectious diseases including urinary disorders, skin diseases and oral diseases. This study was carried out to collect medicinal plant species employed for the treatment of these diseases and to investigate their antimicrobial potential. MATERIALS AND METHODS: Based on an ethnobotanical investigation carried out in three Guinean regions, 74 traditional healers and 28 herbalists were interviewed and medicinal plants were collected. The most quoted plant species were evaluated for their antimicrobial activities against Staphylococcus aureus, Escherichia coli, Candida albicans, and in addition against Plasmodium falciparum. RESULTS: A total of 112 plant species belonging to 102 genera distributed over 42 botanical families were inventoried. Among the selected plant species, promising activities against C. albicans were obtained for the methanolic extracts of the stem bark of Terminalia albida (IC50 1.2 µg/ml), the leaves of Tetracera alnifolia (IC50 1.6 µg/ml) and the root bark of Swartzia madagascariensis (IC50 7.8 µg/ml). The highest activity against S. aureus was obtained for the dichloromethane extracts of the leaves of Pavetta crassipes (IC50 8.5 µg/ml) and the root of Swartzia madagascariensis (IC50 12.8 µg/ml). Twenty one extracts, obtained from twelve plant species, were strongly active against Plasmodium falciparum, including the dichloromethane extracts of the root and stem bark of Terminalia albida root (IC50 0.6 and 0.8 µg/ml), the leaves of Landolphia heudelotii (IC50 0.5 µg/ml), the stem bark of Combretum paniculatum (IC50 0.4 µg/ml) and the leaves of Gardenia ternifolia (IC50 1.3 µg/ml). CONCLUSION: The present study provides a comprehensive overview of medicinal plants employed by Guinean traditional healers for the treatment of various microbial diseases, including urinary disorders, skin diseases and oral diseases. Some of the studied plant species showed promising antimicrobial activity and could be considered as a potential source for the development of new antifungal and/or antimalarial agents.

Terminalia albida treatment improves survival in experimental cerebral malaria through reactive oxygen species scavenging and anti-inflammatory properties.

BACKGROUND: The development of Plasmodium resistance to the last effective anti-malarial drugs necessitates the urgent development of new anti-malarial therapeutic strategies. To this end, plants are an important source of new molecules. The objective of this study was to evaluate the anti-malarial effects of Terminalia albida, a plant used in Guinean traditional medicine, as well as its anti-inflammatory and antioxidant properties, which may be useful in treating cases of severe malaria. METHODS: In vitro antiplasmodial activity was evaluated on a chloroquine-resistant strain of Plasmodium falciparum (K-1). In vivo efficacy of the plant extract was measured in the experimental cerebral malaria model based on Plasmodium berghei (strain ANKA) infection. Mice brains were harvested on Day 7-8 post-infection, and T cells recruitment to the brain, expression levels of pro- and anti-inflammatory markers were measured by flow cytometry, RT-qPCR and ELISA. Non-malarial in vitro models of inflammation and oxidative response were used to confirm Terminalia albida effects. Constituents of Terminalia albida extract were characterized by ultra-high performance liquid chromatography coupled with high resolution mass spectrometry. Top ranked compounds were putatively identified using plant databases and in silico fragmentation patterns. RESULTS: In vitro antiplasmodial activity of Terminalia albida was confirmed with an IC50 of 1.5 µg/mL. In vivo, Terminalia albida treatment greatly increased survival rates in P. berghei-infected mice. Treated mice were all alive until Day 12, and the survival rate was 50% on Day 20. Terminalia albida treatment also significantly decreased parasitaemia by 100% on Day 4 and 89% on Day 7 post-infection. In vivo anti-malarial activity was related to anti-inflammatory properties, as Terminalia albida treatment decreased T lymphocyte recruitment and expression of pro-inflammatory markers in brains of treated mice. These properties were confirmed in vitro in the non-malarial model. In vitro, Terminalia albida also demonstrated a remarkable dose-dependent neutralization activity of reactive oxygen species. Twelve compounds were putatively identified in Terminalia albida stem bark. Among them, several molecules already identified may be responsible for the different biological activities observed, especially tannins and triterpenoids. CONCLUSION: The traditional use of Terminalia albida in the treatment of malaria was validated through the combination of in vitro and in vivo studies.

Biological and Phytochemical Investigations on Caesalpinia benthamiana, a Plant Traditionally Used as Antimalarial in Guinea.

Caesalpinia benthamiana is widely used as antimalarial in Guinean traditional medicine. Leaf extracts of the plant were tested for their in vitro antiprotozoal activity against Trypanosoma brucei brucei and T. cruzi and the chloroquine-sensitive Ghana strain of Plasmodium falciparum along with their cytotoxicity on MRC-5 cells. The methanolic extract showed the strongest antiprotozoal activity against P. falciparum (IC50 4 µg/ml), a good activity against T. brucei (IC50 13 µg/ml), and a moderate activity against T. cruzi (IC50 31 µg/ml) along with an IC50 on human MRC-5 cells of 32 µg/ml. Bioassay-guided fractionation from the methanolic extract led to antiplasmodially active subfractions. A prospective, placebo-controlled ethnotherapeutic trial assessed the antimalarial effectiveness and tolerability of C. benthamiana syrup administered orally to children with uncomplicated malaria as compared with chloroquine syrup. Phytochemical screening of the leaf extracts indicated the presence of flavonoids, terpenoids, tannins, saponins, and iridoids.

Management of diabetes in Guinean traditional medicine: an ethnobotanical investigation in the coastal lowlands.

ETHNOPHARMACOLOGICAL RELEVANCE: This survey was carried out in the coastal lowlands of Guinea-Conakry in order to make an inventory of plants used by traditional healers, herbalists and diabetic patients for the management of diabetes mellitus. MATERIALS AND METHODS: Frequent ethnomedical and ethnobotanical investigations were conducted from June 2008 to December 2009 in Conakry, Kindia, Forécariah, Dubréka, Boke, Fria and Boffa. It is a cross-sectional survey and data collection is based on the interactive method. During this period a total of 112 people aged from 39 to 76 years old were interviewed. RESULTS: During this investigation 146 plant species belonging to 55 families were collected. The most cited plants were Anacardium occidentale L. and Ficus spp., while the Fabaceae family was the most represented, followed by the Euphorbiaceae and Rubiaceae. The most frequently plant parts used by the traditional healers and the herbalists were the stem-bark and decoctions the most common preparation mode. CONCLUSIONS: It is clear that a variety of plants is used in the management and treatment of diabetes. Due to the increasing prevalence of type 2 diabetes, there is an urgent need for scientific investigations to rationalise the use of these traditional remedies, which could represent accessible alternative medicines for the Guinean populations.