POISONOUS PLANTS OF ZIMBABWE

Transcription

1 POISONOUS PLANTS OF ZIMBABWE

2 Objectives To be able to identify the poisonous plants in Zimbabwe. To be able to understand their toxicity effects to domestic animals and humans.

3 PLANT METABOLITES

4 INTRODUCTION Cases of plant poisoning to animals and humans are common in Zimbabwe and elsewhere in the world. Most animal poisoning occurs as a result of animals grazing poisonous plants. Children playing with poisonous plants or eating wild fruits. Teenagers who intentionally misuse the plants for hallucinogenic and euphoric effects.

5 INTRODUCTION Traditional herbalists trying to cure some illnesses. Stories of deliberate poisoning by lacing food or drink are sometimes reported in communal areas. Harvested crops can be contaminated with poisonous plant seeds e.g. Datura seeds in wheat.

6 Datura stramonium (Stinkblaar, Thorn apple, Jimson weed)

7 Datura stramonium

8 Datura stramonium

9 Identification It belongs to the family Solanaceae. Annual, shallow rooted with green or purple stems. Fruits are ovoid capsules covered with spines. Seeds are dark brown and can be produced by a single plant. Compressed kidney shaped, finely pitted testas. Seeds remain viable for 20 years or more. Found in arable crops or newly disturbed soils (road sides). Large white, trumpet-shaped flowers.

10 Toxic substances All plant parts are toxic particularly the seeds and leaves. Belladonia alkaloids i.e. atropine, hyoscyamine and scopolamine. Competitive antagonists of muscarinic cholinergic receptors and are central nervous system depressants.

11 Contamination Presence of Datura plants in hay and silage could lead to livestock poisoning. In maize and wheat cotamination of grain with Datura seed can occur. Datura seed need to be removed from crop seed before use. 0.1 mg Atropine per Datura seed. Lethal dosage of Atropine in humans is greater than 10 mg.

12 Symptomps of poisoning Datura toxicity occurs within 60 mins after injestion. Clinical effects persist for 24 to 48 hours. Complete inability to differentiate reality and fantasy- confusion and hallucinatination. Violant behaviour. Photophobia that can last for several days. Blurred vision and urinary retention. Head ache, convulsion, coma and death.

13 Treatment Use benzodiazipines. Physiostigmine used under extreme cases.

14 USES Used by herbalists to relieve bronchial spasm in asthma. The patient inhales the smoke of dried leaves that are being burnt. Used in morden medicine to relieve asthma.

15 Lantana camara (Tickberry, Sage bush)

16 Lantana camara showing red flowers

17 Lantana camara with white flowers and yellow centres

18 Lamtana camara with pinkish flowers with yellow and orange centres

19 Lantana camara with green berries

20 Lantana camara with ripe berries

21 Lantana camara showing branches which are attached to the main stem at right angles to the main stem.

22 Lantana camara showing hooked spines on the stems.

23 Lantana camara leaves are directly opposite each other.

24 Leaves have serrated margins

25 Lantana camara is poisonous to livestock

26 Lantana camara can be poisonous to livestock.

27 Lantana camara growing near cattle pens in communal areas.

28 Identification Plant family Verbanaceae An evergreen shrub reaching a height of 2 to 4 m high. Stems have a square cross section, with hooked spines (prickles). There are various colour forms of flowers, but the most common ones have pinkish flowers yellow centres.

29 Identification The leaves are arranged in opposite pairs. They are oval, rough with short hairs, with finely toothed edges. When crushed they have a strong smell. Fruits are small, black berries clustered in round heads.

30 Distribution Found in the tropics. Pastures and lands abandoned after cultivation. It has been used as a hedge in Zimbabwe its found in urban areas and rural areas. It has been declared a noxious weed and should be destroyed where ever it is seen. Because of its allelopathic properties, it is capable of colonising new areas fast.

31 Toxicity Lantana camara is poisonous to livestock and humans. The fruit and leaves Lantadene A, Lantadene B and Lantadene C. Release toxins in the gastrointestine tract causing photodermititis. Children get poisoned after consuming green buries. In livestock, toxic effects include photosensetisation and gastro intestinal disturbance which may lead to the death of the animal.

32 Solanum nigram L (Black nightshade, musungusungu)

33 Solonum nigram

34 Solanum nigram

35 Solanum nigram showing burries

36 Identification Solanaceae family. Annual branched herb 30 to 90 cm tall. Stems are angular and flowers are white. Fruits are spherical black berries. It is a common weed of disturbed areas and arable lands of Zimbabwe.

37 Toxicity Solanin a glyco-alkaloid found throughout the plant with highest concentration in the unripened fruit. Poisoned calves and goats have been reported. Poisoning of children who eat unripe fruit.

38 Symptoms Headache, Subnormal temperature, Paralysis, Dilated pupils, Vomiting, Diarrhoea, Circulatory and respiratory depression, Shock, Loss of sensation and death.

39 Uses Mature fruit used to make jam, Leaves cooked as relish, Used to treat pain and fever, Diuretic, Resevour for antioxidants.

40 Solanum incunum L. (Nhundurwa).

41 Solanum incanum

42 Solanum incanum flowers

43 Solanum incanum yellow fruits

44 Solanum incanum yellow fruit and blue flowers.

45 Solanum incanum

46 Identification Solanaceae family A shrub which have prickly stems and petioles. Leaves are covered by yellow or brown hairs and are usually velvety. Corrola is purple or violet. Fruits are green when unripe and bright yellow when ripe. Found in pastures especially around ant-hills. Looks like the cultivated egg plant.

47 Toxicity and Symptoms Contains solanin- glyco-alkaloid Symptoms are similar to those of Solanum nigram. MEDICINAL USES Used to treat the following: Chest trouble, snake bite, ear ache and syphilis.

48 Cucumis prophetarum (wild cucumber)

49 Cucumis prophetarum

50 Cucumis spp showing fruit with spines

51 Cucumis spp

52 Identification Cucurbitaceae family. Looks like the cultivated cucumber. Has yellow flowers. Cucumis ficifolius has fruit with broad blunt bristles (spines) and pale yellow stripes. Cucumis prophetarum L has fruit with soft slender spines. Found in Zimbabwe growing as weeds of arable land and pastures.

53 Toxicity Cucumin leptodermin

54 Symptoms Bloody diarrhoea as a result of gastrointestinal lesions. Vomiting Affect lungs and kidneys.

55 Ricinis cummunis L (Castor oil plants, Castor beans).

56 Ricinus communis

57 Castor beans showing the fruit.

58 Ricinis communis L

59 Ricinis communis seeds

60 Identification Euphorbiaceae. Shrub-like herb, branched, 1.5 to 3 m tall. Cultivated as a source of oil in Zimbabwe. Occurs naturally in the north east / west Zimbabwe.

61 Toxicity All parts of the plant are poisonous. Leaves are less toxic than seed. Ricin. Crop seed can be mixed castor bean seed during harvesting and storage. In Malawi cases of unwanted children being killed using ricin have been recorded.

62 Symptoms Muscular incordination. Tetanic spasms of muscles. Profuse watery diarrhoea. Convulsions and death in human beings. 3 seeds can be fatal to a child while 8 would have the same result with an adult. If seeds are swallowed without chewing, poisoning is unlikely because of the hard seed coat.

63 Tribulis terrestris (Delvil s thorn, isihlahamakodlane)

64 Tribulis terrestris

65 Tribulis terrestris

66 Tribulis terrestris

67 Identification Zygophyllaceae family. A plant with prostrate branches, yellow flowers. The fruits are spiny and woody and split into 3 5 parts, each with large spines. In Zimbabwe found in the lowveld. Tribulis terrestris appeared on the list of the aggressive weeds in a weed survey done by Chivinge (1983). Chivinge (1988) reported the presence Tribulis terrestris in Mavingo Province. This weed was increasing. Gelfand, Mavi, Drummond and Ndemera (1985) The Traditional Medical Practitioner in Zimbabwe. 407 pages. -did not report Tribulus terrestris in their survey of medicinal plants in Zimbabwe.

68 Toxicity Three sapogens; diosgenin, ruscogenin and gitogen and nitrates. Wilting of plants has been shown to enhance toxicity.

69 SYMPTOMS Hepatoxicity (liver damage) interferes with excretion of photodynamic agent, phylloerythrin, in the bile. Fever like symptoms and death.

70 Uses

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