Euphorbiaceae

L An extract of the bark of this small tree is used as a purgative and antipyretic and topically in ophthalmias (Oliver, 1960).

C From the rootbark the alkaloids phyllalbine, securinine, phyllochrysine (allo-securinine), phyllanthine (methoxysecurinine) and phyllanthidine have been isolated (Janot et al., 1958; Parello et al., 1963; Parello, 1966; Foussard Blanpin et al., 1967). Earlier, securinine had been found in Securinega suffruticosa by Muraveva and Bankovski (1956). Bevan etal. (1964) have reported in Nigerian species 0.4%, 0.2% and 0.06% of securinine in the rootbark, stembark and leaves, respectively, as well as the minor alkaloid allosecurinine. The phyllan thine formerly reported has been shown to be identical with methoxysecurinine.

P Securinine was shown by Tourova (1957) to have a stimulating action on the CNS comparable to that of strychnine. It increases reflex activity and breathing as well as muscular tone and the blood pressure. It was used by Tourova (1957) in various neuropsychic complaints with satisfactory results (see Securinega virosa). It has been reported to be ten times less toxic than strychnine. The action of phyllochrysine, securinine and phyllalbine have also been investigated in France. Phyllochrysine and securinine are sympathomimetic and excite the CNS. Securinine, however, is more toxic, does not act on the medulla and produces more violent convulsions (Quevauviller et al., 1965). Phyllochrysine does not have local anaesthetic, analgesic or antispasmodic activity. Phyllalbine chloride has a LD50 in mice of 10 nig/kg when given intravenously and of 45 mg/kg when given subcutaneously. It mainly stimulates the suprarenal glands, producing secretion of adrenaline, has peripheral sympathomimetic properties and slightly inhibits monoamine oxidase (MAO) (Quevauviller and Blanpin, 1959; Quevauviller et al., 1965, 1967).

Pauridiantha viridiflora (Schweinf. ex Hiern) Hepper syn. (Urophyllum viridiflorum Schweinf. ex Hiern) RUBIACEAE

L The bark of a related species, P. lyallii (not found in West Africa), has long been used as a remedy for fever and malaria (Pousset et al., 1974).

C From the bark of P. viridiflora growing in the Congo, the following have been isolated: harmane (0.08%); pauridianthine (0.007%) and its isomer pauridianthinine (of pyridine-harmane structure), as well as an anthraquinone and a glycoside, lyaloside (Pousset etal., 1971; Bouquet and Fournet, 1975a; Leveque et al., 1975). P. canthiflora Hook., another species found in West Africa, has been shown to contain only traces of alkaloids (Bouquet, 1970). Harmane and related alkaloids G8-carbolines) have been found in several other African species (P. lyallii, P. callicarpoides) (Pousset etal., 1971, 1974). Harmine and related alkaloids were first detected in Peganum harmala L. (Rutaceae) from India (Henry, 1949). Harmane is 1 -methyl-9//-pyrido-3,4,6-indole and harmine is its 7-methoxy derivative. The configuration of these alkaloids shows a close relationship with that of serotonin (5-hydroxytryptamine) and tryptamine.

P The antipyretic and protozoicidal actions of P. lyallii have been confirmed by Pousset et al. (1974) and the chemical composition of P. viridiflora could justify the same activities. Harmane and its derivatives have similar properties to quinine alkaloids. They are also protozoicidal and are also said to be coronary dilators and oxytocics.

The harmala alkaloids are able to elicit or exacerbate abnormal reactions such as are shown in schizophrenia or in ethanol intoxication and some of their effects are reminiscent of productive symptoms in these cases (Hofer et al., 1950). Thus an isomer of harmaline (6-methoxyharmalane) is a powerful serotonin antagonist, and it is suggestive that the highest concentrations of serotonin have been found in the pineal glands of schizophrenics (Mclsaac et al., 1961; Wooley, 1962; Naranjo, 1967). MAO-active alkaloids can alter 5-hydroxytryptamine and noradrenaline metabolism in the brain, producing enhancement of the serotonin effect on body temperature and counteraction to reserpine (Pletscher et al., 1959).

The harmala alkaloids have been used in sequels of encephalitis (Hill and Worster-Drought, 1929; Cooper and Gun, 1931; Naranjo, 1967). In large doses they cause tremors and clonic convulsions. Harmine, harmaline and harmol are MAOIs (Burger and Nara, 1965; Slotkin et al., 1970); harmine and harmaline show a short duration of MAO inhibition as compared to the early MAOIs (hydrazine derivatives). Pretreatment with harmaline can therefore reduce undesired secondary effects of these in blocking the MAO molecule receptors (Rommelspacher, 1981).

The harmala alkaloids are cholinergic and antagonistic to benzodiazepines (which are anxiolytic, anticonvulsive, muscle-relaxing and sleep-inducing). They are a group of substances with a broad spectrum of activity differing from compound to compound and require further research (Holmstedt, 1967; Rommelspacher, 1981). The LD50 of harmaline given subcutaneously, is 120 mg/kg for rats and mice; that of harmine is 200 mg/kg. The human therapeutic dose of harmine, given perorally, is 300-400 mg (Usdin and Efron, 1976).

Nauclea latifolia Sm. syn. (N. esculenta (Afz. ex Sab.) Merrill, Sarcocephalus esculetitis Afz. ex. Sab., S. sassandrae Chev., 5. sambucinus Schum., S. russeggeri Kotschy ex Schweinf.) RUBIACEAE

African peach, guinea peach, doundake

L In Nigerian local medicine, the fruit is sometimes dried and used in the treatment of piles and dysentery. Eaten in excess the fruit acts as an emetic. The bitter bark has been widely used locally, in the form of an infusion or decoction, as a tonic and antipyretic. It is called 'African quinine'. In Northern Nigeria, a cold infusion of the bark is taken as a diuretic and anthelmintic, and to regularize bowel functions. The stembark has been used as a haemostatic, N. latifolia is also a timber tree and frequent intoxication (headaches and nausea) of the workmen cutting up the trees may be attributed to an alkaloid, found in the leaves, which has a marked and cumulative cardio-inhibiting action (Caiment-Leblond, 1957). The root of N. pobeguinii is prescribed in local medicine in Senegal as a powder for abdominal pains and as an oxytocic in the form of a decoction (Kerharo and Adam, 1974).

C Different indolo-quinolizidine alkaloids and glyco-alkaloids have been isolated from the rootbark. The former have been identified and named angustine, angustoline, angustifoline, nauclefine and naucletine (Dimitrienko et al., 1974; Hotellier et al., 1975). The glyco-alkaloids have been identified as cadambine and 3-a-dihydro-cadambine. These two alkaloids have also been reported to be present in the leaves of N. diderrichii (de Wild. & Dur.) Merrill in Senegal (McLean and Murray, 1970). Patel and Rowson (1964) noted the presence of heterosides in the rootbark of N. latifolia and Hotellier et al. (1977) isolated a precursor from it called strictosamide, which is closely related to vincoside lactam. The simultaneous presence of indolo-quinolizidine alkaloids and of corresponding heterosides seems to indicate a biogenetic relationship in this family of Rubiaceae; similar observations had already been made concerning N. diderrichii and Pauridiantha leyallii Brem. (Leveque et al., 1975). The leaves of N. latifolia yield 0.8% of alkaloids, including naufoline and angustine, and the same two glyco-alkaloids which had been reported in the rootbark (Hotellier et al., 1979). Harmane, pyridine and indole-pyridine alkaloids have been isolated from N. diderrichii (de Wild. & Dur.) Merrill, which is also found in West Africa (McLean and Murray, 1970).

P In the guinea pig an intraperitoneal injection of an aqueous extract of the leaves and bark of N. latifolia collected in Nigeria equivalent to 6 g/kg produced a lowering of the rectal temperature of 2°C, which lasted for several hours, and in dogs an aqueous extract of the leaves was reported to have distinct hypothermic action and to produce a sudden decrease of the carotid pressure followed by the opposite effect and by renal vasoconstriction (Raymond-Hamet, 1937). A non-identified (possibly indolic) alkaloid isolated from the roots in Portuguese Guinea by Almeida et al. (1963)

produced an inhibiting effect on smooth muscles and was anticholinergic (Correia da Silvaetal., 1964).

Cardio-inhibiting and cardiotonic activity of extracts of the leaves and bark were reported by Patel and Rowson (1964). The leaves of N. latifolia have anticancer action against transplantable sarcoma 180 tumours and against Lewis lung carcinoma, producing a reduction of 43% and 53% respectively (Abbott et al., 1966).

Justicia insularis Anders syn. (Adhatoda diffusa Benth., J. galeopsis Anders, Siphonoglossa macleodiae Moore) ACANTHACEAE

L The plant does not seem to be used medicinally in West Africa. In the Kumaon region (India), it is used as an antifatigue and stimulating plant (Ghosal et al., 1979a, 1981).

C In India and Japan a number of Justicia spp. have been screened as they produce a large number of aryl-naphthalide lignans with antidepressant properties. Thus, J. prostata has been shown to contain the prostalidins A, B, C and tetrochinensin (4-aryl-2,3-naphthalidine lignan). In J. hayatai var. decumbens and J. procumbens var. leucantha (from Formosa and Japan) a number of aryl-naphthalide lignans (sesamin, asarin, sesamolin) and in J. simplex a new lignan, simplexolin, have been recorded (Ghosal et al., 1979a, b, 1981). P Pharmacological screening of these lignans revealed significant action on the CNS in animals. The prostalidins A-C produced a mild antidepressant action in albino mice and rats. The action was potentiated by carpacin, which itself showed only a weak sedative action. The combined active constituents have a low toxicity (Ghosal et al., 1979b). Another biological activity reported for bicyclo-octane lignans is the reversal of sickling and crenation in erythrocytes by plant extracts containing similar constituents (Sofowora et al., 1975).

Tabernaemontana crassa Benth. syn. (T. durissima Stapf, Conopharyngia durissima (Stapf) Stapf) APOCYNACEAE

Tabernaemontana pachysiphon Stapf var. pachysiphon syn. (Conopharyngia pachysiphon (Stapf) Stapf) L A decoction of the leaves of T. crassa is taken in West Africa as a tonic, appetizer and aphrodisiac whilst the juice of the bark is used in the treatment of leprosy and for wound disinfection (Kerharo and Bouquet, 1950).

In Nigeria and Ghana, the rootbark of T. pachysiphon is used as an infusion in the treatment of manias (Ainslie, 1937; Irvine, 1961; Watt, 1967). The rootbark of some species is said to be strongly sedative (Watt, 1967). C In the roots and bark of T. crassa, indole alkaloids, isovoacangine, conopharyngine, conodurine, conoduramine and coronaridine, and in the seeds, voacamidine, coronaridine-hydroxyindolenine, tabersonine and coronaridine have been reported (Dass et al., 1967). Although coronaridine is closely related to ibogaine (Gorman et al., 1960), the narcotic alkaloids found in T. iboga, such as ibogaine, ibogamine and tabernanthine (Tyler, 1966; Pope, 1969), could not be detected in T. pachysiphon or T. crassa (Taylor, 1957; Dickel et al., 1958). By thin-layer chromatography, Patel et al. (1967) could detect in the bark of Nigerian T. pachysiphon c. (cultivated) coronaridine, conopharyngine and voacangine plus small amounts of a number of non-identified alkaloids. Conopharyngine and ibogaine were reported in T. contorta (Stapf) Stapf. All known Tabernaemontana spp. thus appear to be characterized by ibogamine-type alkaloids (Haller and Heckel, 1901).

P T. crassa Benth, when intraperitoneally injected (suspension of a crude extract) in rats, produced decreased motor activity and muscle relaxant effects: the pupil of the eye was dilated and there was blanching of the ears. Death occurred 30 min after injection of 250 mg/kg (Sandberg and Cronlund, 1982).

T. crassa and T. pachy siphon have been reported to be stimulants of the CNS and to be hallucinogenic in large doses (Marderosian, 1967). They increase and extend the hypertensive action of adrenaline and also have local anaesthetic activity (Schneider and Sigg, 1957; Raymond-Hamet and Vincent, 1960; Paris and Moyse, 1971, p. 81). Coronaridine hydrochloride, isolated from the roots of the Indian T. heyania, but also present in the above-mentioned species, has been shown to prevent pregnancy in rats when administered 1-5 days post coitum (Mehrotra and Kamboj, 1978).

Cannabis sativa L. var. indica Lam. CANNABINACEAE

L The plant is nowadays subject to government restrictions in most West African countries (Nigeria, Ghana, Senegal, etc.). Formerly, it was used as an antidote to snake poison and to treat malaria and blackwater fever (Hager's Handbuch, 1972, Vol. Ill, p. 652).

C The narcotic resin is obtained from the dried flowering or fruiting tops or from the green shoots (the quality varies with the district from which it comes). The resin exudes from the surface during growth and is collected by pressing the tops or flailing the stems. It contains cannabinol, cannabidiol and several isomeric tetrahydrocannabinols, which are the chief active principles. The two main psychomimetically active components are the (-)iransA1- and (—)iransA6-isomers (Kettenes-van den Bosch et al., 1980). In addition, cannabigerol, cannabichromene and cannabitriol have been reported. The amount of exudate is low in temperate regions and high in warmer regions. Choline, trigonelline and a coumaric glycoside have also been found in the tops (Gaoni and Mechoulam, 1964; Schulz, 1964; Farnsworth, 1969; Turner et al., 1980). Ten flavonoid glycosides have been isolated by column and paper chromatography. One was found to be the acyl derivative of apigenol, the others are O-glycosides and C-glycosides (vitexine, isovitexine and orientine) (Paris et al., 1976).

P Cannabis has been used in veterinary medicine as a sedative in the treatment of equine colic (Merck Index, 1976, item 1748) and in man as an analgesic and hypnotic and in the treatment of depressive mental conditions (Paris and Moyse, 1967). The analgesic effect is considered to be a consequence of its general effect on the cerebral cortex (Kettenes-van den Bosch et al., 1980). It is rarely prescribed even in the countries where its medicinal use is still authorized. It is known under many local names such as ganjah, bhang or charas in India, marihuana in North America, hashish (purified alcoholic extract) in North Africa, kif in Morocco, takrouri in

Tunisia, dagga in South Africa, etc. Its production and use has been forbidden in 74 countries since 1956 and the 1961 New York Convention (Paris and Moyse, 1967).

When ingested or (more frequently) inhaled as smoke, the drug first produces a state of euphoria, intellectual excitement and indifference to surroundings, then come illusions, loss of the notion of time and space, hallucinations, incoordination of movements and drowsiness but not complete unconsciousness. The psycho-mimetic effect is more rapid with smoking than with ingestion (Hagefs Handbuch, 1972; Paton, 1975).

Toxic effects of prolonged use of C. sativa include lassitude, indifference, lack of productive activity, insomnia, headaches, nystagmus, increased susceptibility to infections, gastrointestinal disturbances, sexual impotence and personality changes. The slow and prolonged hypotensive action of the drug, and its interaction with catecholamines in the peripheral system, suggest the possibility of an interaction with the brain amines being responsible for the behavioural effects observed (Arora et al., 1976). Kettenes-van den Bosch et al. (1980) write: 'Investigation as to the therapeutic potential of (-)iransA1-tetrahydrocannabinol as an anticonvulsant, anti-emetic, antiglaucoma, anticancer and analgesic drug have started only recently and the results to date have not been convincing, adverse effects and the development of tolerance have been the limiting factors.' Hence they consider that further investigations are required.

The antibacterial activity of the essential oil of C. sativa was assessed on Staphylococcus aureus, Streptococcus faecalis, Mycobacterium smegmatis, Pseudomonas fluorescens and Escherichia coli. The oil was found to be active on Gram-positive bacteria and has been used against Gram-positive bacteria in cases of resistance against penicillin (Fournier et al., 1978). The antibacterial agent appears to be cannabidiolic acid (Farnsworth, 1969).

Myristica fragrans Houtt. MYRISTICACEAE

Nutmeg

L Myristica fragrans has been introduced into various parts of West Africa as a spice. Essential oil of nutmeg is used externally for rheumatism and internally as a carminative (Oliver, 1960).

C The essential oil is associated in the nut with a solid fat. The oil contains pinene, camphene, borneol, geraniol and eugenol and in the last portions of the distillate, myristicin (methylene-dioxy-methoxyallylphenol) belonging to the phenyliso-propylamines. In addition, elemicin and safrol have been reported (Gottlieb, 1979). The varying proportions of these substances explain the differences in pharmacological action of various samples of nutmeg oil (Shulgin et al. in Efron et al., 1967, pp. 202-14).

P The oil is an aromatic stimulant and in high doses it has convulsant and oxytocic properties. Doses of between 0.2 and 1 g/kg induce dose-dependent light-to-deep sleep in young chicks. In man, the seeds and arils have in some cases hallucinogenic properties (Truitt, 1967; Weil, 1967) although this effect is contested by Shulgin (1966). The ingestion of about 5 g of the seed (about one large nutmeg) can lead after a few hours to a more or less severe physical collapse, weak pulse, hypothermia, clamminess of the extremities, giddiness, vertigo, nausea and a feeling of congestion and pressure in the chest or abdomen. For about 12 h there is an alternation of delirium and stupor, usually resolved by heavy sleep. For several days there may be headaches, dryness of the mouth, tachycardia and perhaps spells of dizziness (Weiss, 1960). Myristicin has been said to be effective in quietening hysteric or delirious patients. The LD50 in rats is less than 1 g/kg. Myristicin has been shown to be a MAOI in vitro and in vivo (Truitt, 1967). It may by degradation undergo transamination, producing 3,4,5-trimethoxyamphetamine; more rapid biodégradation of pure myristicin, in contrast to a slow release, might suggest a greater efficiency of the crude drug (Weil, 1965; Shulgin et al., 1967; Truit, 1967; Forrest and Heacock, 1972).

Daturametel L. syn. (D.fastuosa L. var. D. alba(Nees)C. B. Cl.) SOLANACEAE Datura stramonium L. including D. tatula L. Datura innoxia Mill. syn. (D. metel Chev. Berh.)

Datura Candida (Pers.) Safford syn. (Brugmansia Candida Pers., D. arborea Ruiz & Pavon) (Fig. 3.2)

L In tropical West Africa, Datura spp. are used in native beer or in palm wine to add a stupefying or narcotic effect. Thus, a drink made from the seeds of D. metel is given as an intoxicant to Fulani youth to incite them m the Sharo contest or ordeal of manhood (Dalziel, 1937). A decoction of the seeds has been used for eye diseases (Pobéguin, 1912).

C The main alkaloids, present in all species, are the parasympathetic alkaloids atropine ((±)- hyoscyamine), (-)-hyoscyamine and hyoscine (scopolamine). They are found mainly in the flowers and leaves, and, to a lesser extent, in the seeds. Norscopolamine, meteloidine, hydroxy-6-hyoscyamine and tiglic esters of dihy-droxytropane have been reported as secondary alkaloids (Shah and Khanna, 1963, 1964,1965a, b; Shah and Saoje, 1967). D. metel is the species richest in hyoscine, the leaves containing approximately 0.5% of total alkaloids of which three-quarters consists of hyoscine. The total alkaloid content of D. stramonium leaves is roughly the same, but of this over two-thirds is hyoscyamine/atropine. In D. innoxia leaves hyoscine predominates, whilst in the seeds it is the hyoscyamine/atropine fraction which predominates. It was shown that in young leaves of D. metel hyoscyamine is the main alkaloid, but in adult leaves it is hyoscine. In D. stramonium, however, the proportions are inverted and hyoscyamine predominates in adult leaves (Jentzch, 1953). Hyoscine is formed in the leaves by epoxidation of hyoscyamine. Long and intense exposure of the plants to light produces an increase in the hyoscine content. The amount of alkaloids present also varies with the origin of the plants and can be increased by various methods, such as deflowering, mutations, fertilizers, etc. (Paris and Cosson, 1965; Karnick and Saxena, 1970a, b). Balbaa etal. (1979) could increase the percentage of active constituents in D. tatula by more than 100% above the control level through the use of fertilizers.

P Datura spp. are very toxic and their alkaloids can produce delirium with vertigo and hallucinations. The three main Datura alkaloids have both peripheral and central actions. By local application to the eye, (—)-hyoscyamine and atropine cause a pronounced and long-lasting mydriasis due to paralysis of the circular muscle of the eye. They also paralyse the ciliary muscle. The mydriasis produced by hyoscine is of shorter duration but quicker in onset than that produced by atropine. These alkaloids are therefore used as eye drops to dilate the pupil and to paralyse accommodation. They antagonize the activity of the parasympathetic nerves innervating smooth muscles, the glands and the heart by blocking the action of acetylcholine at the post-ganglionic nerve endings (anticholinergic effect) and can be used in conditions where paralysis of the parasympathetic activity is desired, such as bronchial and intestinal spasms. They are constituents of many asthma powders and

Fig. 3.2. Datura candida (Pers.) Safford.

Fig. 3.2. Datura candida (Pers.) Safford.

sea-sickness and anti-chronic bronchitis preparations. Hyoscine also has spasmolytic and peripheral antispasmodic action, but depresses the CNS, whilst atropine stimulates the CNS, and it is a useful sedative and hypnotic for patients with psychomotor agitation, delirium tremens, paralysis agitans and Parkinson's disease. It also finds a use, generally associated with morphine, as a pre-anaesthetic or for relieving withdrawal symptoms in morphine addiction. A subcutaneous injection of 1 mg in adults can induce stupor, confusion of mind and loss of will power, and is reported to have been used for 'brainwashing' (Fattorusso and Ritter, 1967; Karnick and Saxena, 1970b; Lechat etal., 1978).

II Plants with a depressant action mainly via the CNS

The plants of this group often have a simultaneous activity in several sections. This applies particularly to those having analgesic, narcotic, sedative, hypnotic and antipyretic activity: each effect may be the predominating consequence of a general action on the cerebral cortex (Turner and Richens, 1978).

Narcotic analgesics cause unconsciousness and produce sleep through aboliton of the reflexes, including the sense of pain, by paralysing the nerve centres. They cause respiratory depression and a reduction in the motility of smooth muscles (causing constipation, spasm of the sphincter of Oddi and bronchoconstriction). Most narcotics have at first a short stimulating action on the nervous system but then cause a depression with dumbness and stupefaction. An example of a powerful analgesic is morphine. Minor analgesics can abolish the sensation of pain without producing loss of consciousness. Some may have, in addition to the analgesic action, antipyretic or anti-inflammatory activity.

Hypnotics produce sleep (without abolishing the reflexes). Sedatives and tranquillizers decrease watchfulness and calm down motor activity and agitation, and tranquillizers more particularly weaken exaggerated emotional reactions and attenuate restlessness. Even in strong doses they are not hypnotic but some relax skeletal muscles (Lechat et al., 1978). These drugs are used especially in alleviation of the symptoms of schizophrenia and allied disorders and have also been called 'anxiolytics'.

Anticonvulsants lower the excitability of certain central neurones and thus are used to inhibit or diminish the excessive nerve impulses in epileptic convulsions. Different forms of epilepsy (petit and grand mal, psychomotor epilepsy) are caused by lesions of the psychomotor connections in the cortical regions of the brain. They are characterized by convulsions, loss of consciousness and changes in the electrocardiogram. In seizures the central inhibition is suppressed and abnormal nerve impulse activity occurs in small feedback loops (Burgen and Mitchell, 1972). Antiepileptics act by central inhibitory processes.

Antipyretics regulate the body temperature by reducing hyperthermia to normal values. A raised temperature induces peripheral vasodilatation and increased perspiration in an attempt to restore the temperature to normal. The exact mechanism by which antipyretics regulate this process is still not known. A number of plants originally studied for their antipyretic effects have ultimately been shown to act on the cause of the fever and have antimicrobial, antimalarial or anti-inflammatory activities. A few, however, like some Holarrhena and some Funtumia spp. containing alkaloids (see Chapters 2 and 5) and perhaps some containing palmatine and related alkaloids (see below), may have true antipyretic-analgesic action. Many plants in this group show several depressant activities simultaneously. Those described in Chapter 2 (The cardiovascular system) are listed in Table 3.4.

Rhigiocarya racemifera and Kolobopetalum auriculatum (Menispermaceae) are reported to have analgesic effects attributed to o-methylflavinanthine which has a structure similar to that of morphine. Two other Menispermaceous plants, Jateorhiza macrantha and Tinospora bakis, are reported to depress the CNS and to have antipyretic and hypotensive activity. Khaya senegalensis (Meliaceae) is a sedative, anticonvulsant and antipyretic(P). Sedative and analgesic action is shown by Andira inermis (Fabaceae) and sedative and spasmolytic effects alongside a respiratory excitant action (due to nupharine) in Nymphaea lotus (Nymphaeaceae). Anogeissus leiocarpus (Combretaceae) has CNS antidepressant activity. Elaeocarpus sphaericus and Passiflora foetida have been noted to possess, respectively anticonvulsant and hypnotic and anticonvulsant and sedative properties. Antispasmodic action was also reported in Guiera senegalensis. Spasmolytic and hypnotic action was found in Alstonia boonei (Apocynaceae), which also has cholinergic properties. A sedative effect on the CNS and a stimulant action on the medulla has been found in Waltheria indica (Sterculiaceae) and sedative and anticonvulsant actions have been reported for Piper guineense (Piperaceae). The essential oil of Anacardium occidentale has tranquillizing and antispasmodic properties.

Although in all these plants several chemical constituents have been identified, it is not always clear which components are responsible for the various activities.

Rhigiocarya racemifera Miers syn. (R. nervosa (Miers) Chev.)

MENISPERMACEAE Kolobopetalum auriculatum Engl. syn. (K. veitchianum Diels)

L In Sierra Leone the root of R. racemifera is scraped and put in palm wine .Both plants are used for sleeplesness (Dalziel, 1937).

C From these two species, o-methyl-flavinanthine has been isolated. This compound has a structural formula very similar to that of morphine (Gyang et al., 1964). In R. racemifera, the alkaloids liriodenine, palmatine, menispermine (N-methyl-isocorydine) and magnoflorine have also been found (Mehrotra and Kamboj, 1978; Dwuma Badu et al., 1980).

P o-Methyl-flavinanthine has been reported to have a morphine-like inhibitory action on the peristaltic reflex of the guinea pig's isolated ileum and on the contractions of the guinea pig's ileum obtained by coaxial electrical stimulation (Gyang et al., 1964; Gyang and Kosteilitz, 1966). The depressant effect was dose-dependent and the dose-response was more reproducible with the alkaloid than with morphine. The effect was not antagonized by nalorphine (Noamesi and Gyang, 1980). o-Methyl-flavinanthine has been shown to have an analgesic activity equivalent to one-fifth that of morphine. Reduction of the ketonic group to an alcohol may increase the analgesic action (Tackie etal., 1974c).

Jateorhiza macrantha (Hook.) Exell & Mendon$a MENISPERMACEAE

L This species is closely related to J. palmata (Calumba root) which is naturalized in Ghana and locally used as a bitter tonic and in the treatment of dysentery in Indian (Oliver-Bever, 1968).

C The root contains, in addition to colombin, related substances such as chasmanthin and palmarin. It also contains 2-3% of alkaloids of the berberine group: colom-bamine, jateorhizine and palmatine (Chopra el al., 1956; Barton and Elad, 1956, 1962).

P The alkaloids colombamine, jateorhizine and palmatine depress the CNS, and when injected intravenously are hypotensive in the frog. Palmatine, the most active, acts mainly on the respiratory system and the blood pressure. The two others increase the intestinal tonus (see Tinospora bakis) (Paris and Beauquesne, 1938; Henry, 1949). Calumba root (J. palmata), used as a stimulant for patients with atonic dyspepsia, contains no tannins, so it can be prescribed with iron salts. However, its use has been mainly limited to veterinary medicine (Martindale, 1958) as it has occasionally been reported to produce toxic phenomena such as vomiting, paralysis of the CNS and depression of the respiratory centre (Paris and Moyse, 1967, p. 180).

Tinospora bakis (A. Rich.) Miers syn. (Cocculus bakis A. Rich.)

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  • uranio
    Is rhigiocarya racemifera hypnotic plant?
    5 years ago

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