Swamp ebony, monkey guava
L In northern Nigeria an infusion of the leaves is given for fever and dysentery and is applied in wound dressings as a haemostatic. A decoction of the rootbark is given for skin eruptions and also as an anthelmintic in human and veterinary medicine (Dalziel, 1937; Oliver, 1960).
C Many Diospyros spp. were found to contain hydroxy naphthoquinones such as plumbagin (2-methyl-5-hydroxy-l,4-naphthoquinone), diospyron, diospyrol and diosquinone. Plumbagin (originally found in Plumbago), occurs in the rootbark of D. mespiliformis (0.9%) and of D. canaliculata de Wild. (D. xanthochlamys) (2.25%) and also in the leaves of these species (traces and 0.12%, respectively). Further, tannins, a saponin and a substance probably identical to scopolamine have been reported in both species (Kerharo and Bouquet, 1950; Paris and Moyse-Mignon, 1949a).
P In doses of 0.2 g/kg a rootbark extract of D. mespUiformis produces hypertension and exaggerated respiration in dogs. The rootbark of all the species here noted and of D. tricolor (Schum. & Thonn.) Hiern has an antibacterial action on staphylococci, streptococci and diphtheria bacilli probably due to plumbagin. Besides the antibiotic action, insecticide and anthelmintic properties have also been reported in the various species of Diospyros (Paris and Moyse-Mignon, 1949a). As the naphthoquinones also have a vitamin K action, their local application in wound dressing seems fully justified (Fieser etal., 1941).
Jatropha curcas L. EUPHORBIACEAE
Physic nut, Barbados nut
L The oil of the seeds has a purgative action and is used all over West Africa in local medicine as a remedy for dropsy, sciatica, paralysis and skin diseases (Dalziel, 1937).
C The seeds contain 50% of a fixed oil, pinhoen oil, as well as a mucilage composed of xylose, galactose, rhamnose, galacturonic acid and a toxalbumin, curcin (Bezanger-Beauquesne, 1956; Mourgue et al., 1961a, b). Glycosides have been detected in an extract of the shell (Bose et al., 1961).
P The mucilage fraction of the seed pulp reduces prothrombin time and coagulation time. Its effect is comparable to that of Russel's viper venom used as a source of thromboplastin. It is four times less active, however. On the other hand, the toxalbumin fraction has been found to increase the prothrombin time (Bose et al., 1961). Curcin has many features in common with ricin but is less toxic. The purgative action of the seed oil has been confirmed. In addition the seeds have a certain value as an insecticide. Fruits and seeds contain a contraceptive principle (Mameesh, 1963). An ethanolic extract of J. curcas has shown confirmed in vitro and in vivo action against P388 lymphocytic leukemia (Hufford and Oguntimein, 1978).
Group C2: plants with an antivitamin K action (haemolytic action).
Balanites aegyptiaca (L.) Del. syn. (Ximenia aegyptiaca h.,Agialida senegalensis v. Tiegh., A. barteri v. Tiegh., B. zizyphoides Mldbr. & Schltr., A. tombouctensis v. Tiegh.) ZYGOPHYLLACEAE
Desert date, soap berry tree, thorn tree
L In Hausa medicine (northern Nigeria), roots and bark are used as a purgative and in colic, and are considered ichthyotoxic and anthelmintic. The oil of the fruit kernels is employed for the dressing of wounds and as an embrocation in rheumatism (Dalziel, 1937; Oliver, 1960).
C From the dried seeds, 48% of a fixed oil, Zachun oil, has been obtained, whilst the seedcake contains 50% protein. The root, bark, fruit, leaves and seeds contain saponins (Kon and Weller, 1939). In the seeds, 6.7% of a tetraglycoside of diosgenin has been reported. The diosgenin content of the whole dried African plant was 5.6% (Hardman and Sofowora, 1972). In the other parts of the plant the genin consisted of two-thirds yamogenin and one-third diosgenin. B. aegyptiaca has been investigated as a source of steroidal sapogenins for the hemisynthesis of corticosteroids and hormones (Marker, 1947; Hardman and Sofowora, 1972).
P The root, bark, fruit pulp and seeds have been found to be lethal to fish and also to freshwater snails, which act as an intermediate host for bilharzia, and to the minute free stages of the parasite. The planting of Balanites alongside infested rivers to combat bilharzia propagation was therefore recommended by Archibald m 1933. Since then, other plants with stronger molluscicidal properties, such as Polygonum senegalense have been reported (Dossaji et al., 1977). Tephrosia and Jatropha curcas (mentioned above) are also lethal to the molluscs. Antimicrobial properties were reported by Malcolm and Sofowora (1969). The saponoside is strongly haemolytic, with a toxicity to tadpoles similar to that of digitoxin, but less rapid in action. At a concentration of 10"6 of the saponoside in water, the tadpoles survive for more than 24 h. On frog's heart, a dose of 1 mg given subcutaneously produces no apparent digitalis effect; the isolated heart is stopped by a dilution of 10"3. Thus a digitalis-like action exists but it is so weak as to be almost negligible (Caiment-Leblond, 1957).
In Schwenkia americana and in Carica papaya, described earlier, as well as in Swartzia madagascariensis Desv. fruit (Beauquesne, 1947), the presence of haemolytic saponosides has also been reported. In Swartzia these have been named Swartzia saponosides A and B, the genin of them being swartzigenin. The drug is ichthyotoxic and is strongly haemolytic (Beauquesne, 1947).
Group C}: plants with an anti-anaemic action.
Although a few plants have been recommended for the treatment of anaemia in local West African medicine, their action has not been confirmed. No plants possessing a proven anti-anaemic effect seem to have been reported, nor has mention been made of folic acid or vitamin B,2 contents in West African plants. Spinach, yeast, Streptomyces griseus and S. aureofaciens seem to remain the only few, generally known, vegetable sources of these compounds. In sickle cell anaemia, Zanthoxylum zanthoxyloides has been used, as mentioned under the description of this plant.
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