Topics • Poisonous Plants Poisonous Plants � Cassava & Bitter Almond & Residues � Water Hemlock � Poison Hemlock Dean O. Cliver � Death Camas (materials from Michael E. Mount) • Drug Residues Cassava – Background Poisonous Plants – Cassava • Scientific name: Manihot esculenta (C) • A perennial woody shrub. • Grown as a root crop in • Family: Euphorbiaceae the tropics. • Other names: yuca, manioc, and mandioca • The 4 th most important • It originated in South / Central America. source of calories for • Two distinct types of cassava exist ⎯ the humans among crops sweet and the bitter. produced in the tropics. Cassava – Production Cassava – Production • An important staple for about 800 million • Cassava . people worldwide. – important basic energy source for humans. • ~ 172 million tons produced worldwide in – that can be produced on marginal agricultural lands . 2000. • Addresses growing food deficits. � Africa accounted for 54%. – poverty-stricken regions. � Asia 28%. – third world countries . � Latin America and • Other Uses . the Caribbean 19%. – animal feed. – industrial production of starch. 1
Cassava – Drawbacks Cassava – Drawbacks • Cyanide toxicity occurs only in certain areas of Africa. • Undesirable food that contains • Associated with severely deficient little besides carbohydrate. diets. • Cyanide present in the plant. • Under-processing of cassava as a food source. –Harvesting the crop. –Time of drying and loss of the HCN. Cassava – Characteristics • Planted by cutting woody part of the stem. • Grows well in low fertility soils. • Tolerates long periods of drought. • The roots develop into starch storage at about three months of age. Poisonous Plants – Cassava Poisonous Plants – Cassava • Harvest can be anytime following this • Raw cassava has two cyanogenic or up to 2 − 3 years. glycosides. –Linamarin. • Roots stored in the ground from up to –Lotaustralin. 24 months, some varieties up to 36 –These are not considered directly toxic. mo. –Release prussic acid (hydrogen cyanide; HCN). 2
Poisonous Plants – Cassava Poisonous Plants – Cassava Following ingestion: • The body is able to detoxify low levels of Linamarin → Glycoside + Cyanohydrin → cyanide in the body through the action of an enzyme, rhodenase: HCN Released (Toxic Agent) HCN + sulfur → SCN (thiocyanate) • HCN targets the ferric iron (Fe +3 ). – "a"- cytochrome. • Poisoning occurs when exceed. – Electron transport system in mitochondria. – Acute. – Chronic. Almonds Poisonous Plants – Cassava • Sweet Almonds • Syndromes: – Amygdalus communis var. dulcis . � I. Tropical ataxic neuropathy – Confectionery nut. – Health food; essential oils. � II. Epidemic spastic paraparesis. • Bitter Almonds � (Chronic exposure) goiter – Amygdalus communis var. amara . – Commercial source of essential oils. – Cake of fruit contains amygdalin. Cyanide poisoning Amygdalin Prussic Acid Benzaldehyde Produces the “bitter almond” smell Sweet Almond 3
Poisonous Plants – Water Hemlock • Cicuta douglasii (Western water hemlock) and C. maculata (Spotted Bitter Almond water hemlock) are two plants of concern in California. • Other species across USA. • Belong to the Parsley family ( Umbelliferae=Apiaceae ) Poisonous Plants – Water Hemlock Poisonous Plants – Water Hemlock • Western water hemlock – Northern and central California. • The plants are perennial • Spotted hemlock herbs. – Central, southern California/Modoc county. • The leaves are twice- – This plant and its varieties are spread across compound and the the US. segments are not • Habitat divided. – Fresh water streams, ditches, and marshes, – The most poisonous plants in Northern Hemisphere. http://cal.nbc.upenn.edu/ Poisonous Plants – Water Hemlock • Roots are tuberous and show a series of cross- partitions containing a yellow liquid. Western waterhemlock Spotted waterhemlock 4
Poisonous Plants – Water Hemlock Poisonous Plants – Water Hemlock • The whole plant is toxic. • The flowers are white – The root especially contains visible yellow and in large, open, liquid. compound umbels. – Leaves are also very toxic early in the spring. • The seeds are flat faced • All domestic and wild animals are susceptible. to concave. • Man is susceptible. – Mis-identification of an edible plant: • Edible parsnip plants ( Pastenica sativa , Lomatium sp., Sium suave ). www.rce.rutgers.edu Sium suave Sium suave Water hemlock root Water parsnip root Water hemlock flower Water parsnip flower Poisonous Plants – Water Hemlock Poisonous Plants – Poison Hemlock • The plants contain cicutoxin ⎯ a neuropoison. • Conium maculatum is a common weed, • Clinical signs within 15 − 60 minutes of nationwide. ingestion: n ausea, salivation, emesis, • Poison hemlock is in the Umbelliferae family. trismus (tetanic spasm of jaw muscles), – A tall plant with a long, white, often branched toxic-clonic convulsions tap root. • Unconsciousness, cardiac arrest, and peracute – The stem is stout, smooth, and dotted with irregular purple marks. death. – Leaves finely divided. • Treatment is invariably futile once signs occur. 5
Poisonous Plants – Poison Hemlock Poisonous Plants – Poison Hemlock • It has a mouse- • The plant is mistaken for wild carrot by persons like odor. who desire to "live off the land." Poisonous Plants – Poison Hemlock Poisonous Plants – Poison Hemlock • Exposure of pregnant animals causes congenital malformations, particularly in • The roots and seeds are the most toxic, cattle and pigs. but all parts of the plant are poisonous • Other animals can be affected too. since the poison accumulates with age –Time of exposure during gestation in the seeds, roots, stems and leaves. important. • The degree of toxicity varies. –Exposure of a woman should not produce problems. Poisonous Plants – Poison Hemlock Poisonous Plants – Death Camas • Used as a lethal agent historically. • Zigadenus sp (Death Camas) is a • Socrates was forced to drink an herbal of member of the lily family (Liliaceae). this plant. He then described t he course • A herbaceous perennial plant with onion-like bulbs. of the poisoning. • Has slender folded linear leaves. • Ascending paralysis leading to arrest of • A single showey flowering raceme respiration. characterizes the plant with • A convulsive syndrome may occur, yellowish-white colors. • Plant sprouts very early in the spring. particularly if roots or seeds are eaten. 6
Poisonous Plants – Death Camas Poisonous Plants – Death Camas • Clinical signs • Treatment –Vomiting, nausea and abdominal pain – Removal. within one hour of ingestion. – Correction of hypotension with fluids and –Heart rate slows down (bradycardia is vasopressors. present). – Atropine to correct bradycardia. – More serious signs require –Generally, more serious signs do not • artificial ventilation develop in adults. • drugs to control seizures. –Severe illness may occur in children. • Patients respond favorably. Drug Residues Drug Residues • Definition : The concentrations of drugs or • Definition: environmental chemicals that are detectable Residues refer to the parent drugs or by analytical methods are defined as drug or chemicals, their metabolites, and chemical residues in tissues of food their decomposition products, if producing animals and other agricultural commodities for human consumption. formed. Drug Residues Drug Residues • Residues are either intentional or • The quantity of residue if detected is unintentional. expressed by weight: –Intentional residues result from a desired mg of drug present /kg of tissue (ppm) usage of the drug in animals or food µg of drug present /kg of tissue (ppb) products. –Unintentional residues are caused by units /L when in fluids events that exposed animals or food products to drugs or chemicals, not intended to be received by them. 7
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