Drissa Diallo

Ethnopharmacological survey of different uses of seven medicinal plants from Mali, (West Africa) in the regions Doila, Kolokani and Siby.

An ethnopharmacological survey was carried out to collect information on the use of seven medicinal plants in rural areas in the nearby regions of Bamako, Mali. The plants were Opilia celtidifolia, Anthocleista djalonensis, Erythrina senegalensis, Heliotropium indicum, Trichilia emetica, Piliostigma thonningii and Cochlospermum tinctoriumAbout 50 medical indications were reported for the use of these plants in traditional medicine. The most frequent ailments reported were malaria, abdominal pain and dermatitis. The highest number of usages was reported for the treatment of malaria (22%). The majority of the remedies were prepared from freshly collected plant material from the wild and from a single species only. They were mainly taken orally, but some applications were prepared with a mixture of plants or ingredients such as honey, sugar, salt, ginger and pepper. Decoction of the leaves was the main form of preparation (65%) and leaf powder was mostly used for the preparation of infusions (13%). The part of the plants most frequently used was the leaves. There was a high degree of informant consensus for the species and their medicinal indications between the healers interviewed.The results of this study showed that people are still dependent on medicinal plants in these rural areas of Mali.

A “reverse pharmacology” approach for developing an anti-malarial phytomedicine

A “reverse pharmacology” approach to developing an anti-malarial phytomedicine was designed and implemented in Mali, resulting in a new standardized herbal anti-malarial after six years of research. The first step was to select a remedy for development, through a retrospective treatment-outcome study. The second step was a dose-escalating clinical trial that showed a dose-response phenomenon and helped select the safest and most efficacious dose. The third step was a randomized controlled trial to compare the phytomedicine to the standard first-line treatment. The last step was to identify active compounds which can be used as markers for standardization and quality control. This example of “reverse pharmacology” shows that a standardized phytomedicine can be developed faster and more cheaply than conventional drugs. Even if both approaches are not fully comparable, their efficiency in terms of public health and their complementarity should be thoroughly considered.

Wound Healing Plants in Mali, the Bamako Region. An Ethnobotanical Survey and Complement Fixation of Water Extracts from Selected Plants

Identification of 123 species, belonging to 50 families, used for wound healing in the Bamako region of Mali, was performed in this study. The fifteen species that were most frequently cited by the traditional healers were subjected to chemical and biological studies. Water extracts were subjected to screening for effects on the human complement system in vitro. The monosaccharide composition and the total carbohydrate content of the extracts were also determined. All extracts showed effects on the complement system, but extracts from Biophytum petersianum Klotzsch., Pterocarpus erinaceus Poir, Podaxon aegyptiacus Mont., Stereospermum kunthianum Cham., and Ximenia americana L. had the highest activity. The content of carbohydrate in the extracts varied between 5% and 80% and most of them contained substantial amounts of the monosaccharides arabinose, rhamnose, galactose, glucose and galacturonic acid.

Polysaccharides from the roots of Entada africana Guill. et Perr., Mimosaceae, with complement fixing activity

Entada africana is a tree used in traditional medicine in Mali. The root is, for example, used for wound-healing. Since polysaccharides from other plants are thought to play a role in the wound-healing process, we wanted to study the polysaccharides present in the root of this species. The polysaccharides were extracted with water at 50 and 100 degrees C and were further separated by anion exchange chromatography. The acidic fractions were finally purified by affinity chromatography on a Con A column. The fraction denoted Ea100 acidic I had the highest activity in the complement fixation test system, while the other acidic fractions had minor activities and the neutral fractions were almost negative. Ea100 acidic I has a structure resembling the arabinogalactan-protein type II polymer, which also was demonstrated by the abilities to precipitate with the Yariv reagent. The biological activity was reduced considerably after removal of arabinofuranoside residues by weak acid hydrolysis. The main core of the other polysaccharides extracted with 100 degrees C were pectins resembling the rhamnogalacturonan type I. These fractions also contain arabinogalactan type II structures, shown by the formation of precipitates with the Yariv reagent.

The malian medicinal plant Trichilia emetica; studies on polysaccharides with complement fixing ability

Trichilia emetica is a tree or bush that has many different traditional uses in Mali, amongst others the leaves have been used as a woundhealing remedy. As polysaccharides have been isolated from other plants that have a long tradition as woundhealing remedies, it was of interest to study the polysaccharides of T. emetica as well. The polysaccharides were extracted at 50 and 100 degrees C, and the polymeric material was separated into neutral and acidic polymers by anion exchange chromatography. The complement fixation ability of the different fractions was determined. The Acidic fraction 4 of the 100 degrees C extract was the most active, but most of the other fractions were also quite active. Structural studies showed that the most active fraction was a pectin of the rhamnogalacturonan type 1 with side chains of the arabinogalactan type II. Removal of terminal arabinofuranosides lead to a drop of the activity indicating that this structural unit may be involved in the bioactive site of the molecule.

Pectic polysaccharides from Biophytum petersianum Klotzsch, and their activation of macrophages and dendritic cells.

The Malian medicinal plant Biophytum petersianum Klotzsch (Oxalidaceae) is used as a treatment against various types of illnesses related to the immune system, such as joint pains, inflammations, fever, malaria, and wounds. A pectic polysaccharide obtained from a hot water extract of the aerial parts of B. petersianum has previously been reported to consist of arabinogalactans types I and II (AG-I and AG-II), probably linked to a rhamnogalacturonan backbone. We describe here further structural characteristics of the main polysaccharide fraction (BP1002) and fractions obtained by enzymatic degradations using endo-alpha-d-(1-->4)-polygalacturonase (BP1002-I to IV). The results indicate that in addition to previously reported structures, rhamnogalacturan type II and xylogalacturonan areas appear to be present in the pectic polymer isolated from the plant. Atomic force microscopy confirmed the presence of branched structures, as well as a polydisperse nature. We further tested whether the BP1002 main fraction or the enzymatically degraded products could induce immunomodulating activity through stimulation of subsets of leukocytes. We found that macrophages and dendritic cells were activated by BP1002 fractions, while there was little response of T cells, B cells, and NK cells. The enzymatic treatment of the BP1002 main fraction gave important information on the structure-activity relations. It seems that the presence of rhamnogalacturonan type I is important for the bioactivity, as the bioactivity decreases with the decreased amounts of rhamnose, galactose, and arabinose. The demonstration of bioactivity by the plant extracts might indicate the mechanisms behind the traditional medical use of the plant.

Argemone mexicana decoction versus artesunate-amodiaquine for the management of malaria in Mali: Policy and public-health implications

A classic way of delaying drug resistance is to use an alternative when possible. We tested the malaria treatment Argemone mexicana decoction (AM), a validated self-prepared traditional medicine made with one widely available plant and safe across wide dose variations. In an attempt to reflect the real situation in the home-based management of malaria in a remote Malian village, 301 patients with presumed uncomplicated malaria (median age 5 years) were randomly assigned to receive AM or artesunate-amodiaquine [artemisinin combination therapy (ACT)] as first-line treatment. Both treatments were well tolerated. Over 28 days, second-line treatment was not required for 89% (95% CI 84.1-93.2) of patients on AM, versus 95% (95% CI 88.8-98.3) on ACT. Deterioration to severe malaria was 1.9% in both groups in children aged </=5 years (there were no cases in patients aged >5 years) and 0% had coma/convulsions. AM, now government-approved in Mali, could be tested as a first-line complement to standard modern drugs in high-transmission areas, in order to reduce the drug pressure for development of resistance to ACT, in the management of malaria. In view of the low rate of severe malaria and good tolerability, AM may also constitute a first-aid treatment when access to other antimalarials is delayed.

Beta-d-(1 → 4)-galactan-containing side chains in RG-I regions of pectic polysaccharides from Biophytum petersianum Klotzsch. contribute to expression of immunomodulating activity against intestinal Peyer’s patch cells and macrophages

The aerial parts of the medicinal plant Biophytum petersianum have a long tradition for being used in Mali and other West-African countries against various ailments such as wound healing and malaria. Previous studies on polysaccharides from water extracts of the aerial parts showed the presence of pectic like polymers with an effect on the human complement system as well as the ability to activate macrophages and dendritic cells. The present study shows that pectic polysaccharide fragments (BPII.1 and BPII.2) as well as the original pectic polysaccharide (BPII) expressed immunomodulating activity against Peyers patch immunocompetent cells. Exo-β-D-(1→3)-galactanase digestion succeeded to decrease IL-6 production enhancing activity against Peyers patch cells of BPII.2, but the activity of BPII.1 did not decrease. Endo-β-D-(1→4)-galactanase digestion reduced the activities of both BPII.1 and BPII.2. BPII.1 and BPII.2 also stimulated IL-6 production enhancing activity against macrophages, and the activities of both pectic fragments were significantly decreased by either enzymic digestion with exo-β-D-(1→3)-galactanase or endo-β-D-(1→4)-galactanase. Trimming of terminal GlcA by exo-β-D-glucuronidase digestion did not affect IL-6 production enhancing activity against macrophages of both pectic fragments. Methylation analyses of endo-β-D-(1→4)-galactanase digestion products showed the characteristic decrement of 4-linked Gal residues in the pectic fragments. These results suggest that β-D-(1→4)-galactan-containing side chains in BPII.1 and BPII.2 play an important role for expression of immunomodulating activity against both Peyers patch immunocompetent cells and macrophages in addition to β-D-(1→3,6)-galactan chains.

Ethnopharmacological uses of Erythrina senegalensis: a comparison of three areas in Mali, and a link between traditional knowledge and modern biological science

This paper describes ethnopharmacological knowledge on the uses of Erythrina senegalensis DC (Fabaceae) in traditional medicine in three different areas (Dioila, Kolokani and Koutiala) in Mali. Data were collected using interviews of traditional healers selected randomly. The main reported diseases for which E. senegalensis was used by the traditional healers were amenorrhea, malaria, jaundice, infections, abortion, wound, and body pain (chest pain, back pain, abdominal pain etc). The fidelity level (which estimates the agreement of traditional healers on the same area about a reported use of the plant) was calculated to compare the results from the three areas. Certain differences were noticed, the most striking was the fact that amenorrhea was the most reported disease in Dioila and Kolokani with 21% of agreement for both areas, while this use was not reported in Koutiala at all. Similarities existed between the three areas on the use of the plant against malaria and infections, although with different degree of agreement among the healers. We also report the results of a literature survey on compounds isolated from the plant and their biological activities. A comparison of these results with the ethnopharmacological information from Mali and other countries showed that some of the traditional indications in Mali are scientifically supported by the literature. For instance, the use of E. senegalensis against infectious diseases (bilharzias, schistosomiasis, pneumonia etc.) is sustained by several antibacterial and antifungal compounds isolated from different parts of the plant. The comparison also showed that pharmacologists have not fully investigated all the possible bioactivities that healers ascribe to this plant.

Bioactive polyphenols in Ximenia americana and the traditional use among Malian healers.

ETHNOPHARMACOLOGICAL RELEVANCE Ximenia americana is a medicinal bushy, spiny shrub or small tree used in Mali in West Africa for treatment of various diseases, most common are infectious and inflammatory ailments. AIMS OF THE STUDY (1) To perform an ethnopharmacological survey on the traditional use of Ximenia americana among healers in Mali. (2) To isolate and identify chemical constituents from the ethanol extract of Ximenia americana leaves and to study their radical scavenging and enzyme inhibitory effects. MATERIALS AND METHODS In five different districts in Mali, 38 healers were interviewed about their medicinal use of Ximenia americana. An aqueous ethanol extract of the leaves of this tree was prepared and further fractionated with liquid-liquid extraction, VersaFlash and Sephadex LH-20 column chromatography, and preparative HPLC. Isolated compounds were identified by 1D and 2D NMR spectroscopy. Extracts, subfractions and isolated compounds were investigated as DPPH radical scavengers and as inhibitors of xanthine oxidase and 15-lipoxygenase. RESULTS Major areas of use by Malian healers were against throat infection, amenorrhea and as tonic. Fractionation of the ethanol extract led to the isolation and identification of the cyanogenic glycoside sambunigrin (1), which is previously known from the plant. Additionally, gallic acid (2) and the gallotannins β-glucogalline (3) and 1,6-digalloyl-β-glucopyranose (4) were found. The following flavonoids were isolated: quercetin (5), quercitrin (quercetin-3-O-α-rhamnopyranoside) (6), avicularin (quercetin-3-O-α-arabinofuranoside) (7), quercetin-3-O-β-xylopyranoside (8), quercetin-3-O-(6″-galloyl)-β-glucopyranoside (9) and kaempferol-3-O-(6″-galloyl)-β-glucopyranoside (10). The flavonoids were active both as enzyme inhibitors and DPPH radical scavengers. CONCLUSION Sambunigrin (1) was the main compound in the EtOAc soluble fraction of the alcoholic extract of Ximenia americana leaves. Gallic acid (2), gallotannins (3-4) and flavonoids (5-10) were identified for the first time in the genus Ximenia. The identified compounds may give a rationale for the traditional use of Ximenia americana in Mali. Healers interviewed reported the use against throat infections, amenorrhea, as tonic, for wound healing and against pain.