Question

Some Natural toxins are produced by plants as a natural defense mechanism against predators, insects or microorganisms, or as a consequence of infestation with microorganisms, such as mold, in response to climate stress (such as drought or extreme humidity). Listed in Table 1 on the following page are the naturally formed substances which can produce toxin during growth, storage or processing. Choose two (2) and identify the following:
● Plant identification (common name, scientific name and family name).

● Found in which food/source.

● Uses of the substance.

● Side effects to the human body.

Table 1. List of naturally formed substances.

1. Prussic acid in cherry, apple and peach pits 2. Coumarins 3. Lectins in Legumes 4. Rhubarb and Oxalic acid 5. Zucchini and Cucurbitacins

[30 marks]

Answer 1

1. Coumarins: Sweet smelling but colourless compounds produced naturally in many plants. Although they have sweet odour (Scent of vanilla) but bitter in taste whick keeps the herbivores away from eating the W plant parts.

Plant Identification: Tonka bean (Common name), Dipteryx odorata (Scientific name) belongs to family Fabaceae.

Food source: Seeds

Uses: Because of its sweet fragrance, it is used in perfumery.

Act as substrate for the synthesis of anticoagulant drug Warfarin.

Natural defense against herbivory in the plant.

Side effects to the human body: If consumed in large doses, It causes heamorrhages, liver problems and affects the heart muscles causing paralysis of the heart.

2. Prussic acid: is the another name for Hydrogen Cyanide (HCN) which is extremely poisonous colourless compound naturally found to be produced in many plants belonging to family rosaceae like apples, cherries, peaches etc. These plants produce small amount of cyanohydrins which slowly release Hydrogen cyanide.

Plant Identification: Apple (Common name), Malus pumila (Scientific name), Rosaceae

Food Source: Seeds

Uses: Protection against herbivory and Used inexplosives and dyeing industries,

Side effects to human body: Cyanide poisoning in body, destruction of brain cells, hypoxia (oxygen deficiency in tissues), death