A little-known danger

摘要

Cyanogenic glycosides are naturally occurring plant toxins found in the seeds and stones of many fruits commonly consumed by humans (Bolarinwa et al, 2015). The most important cyanogenic glycoside is amygdalin, which is contained in fruit belonging to two large groups: Rosaceae and non-Rosaceae species. Amygdalin content is much higher in Rosaceae species (such as apricots, red cherries and apples), where levels range between 0.1 and 17.5 mg/g. In non-Rosaceae species (such as courgettes, honeydew melons, Crown Prince squash) amygdalin content ranges from 0.01 to 0.2mg/g (Bolarinwa et al, 2014).The toxic dose of amygdalin for humans is between 0.5 and 3.5mg/kg (Bolarinwa et al, 2014). A recent UK news item reported a near-death experience in an adult who chewed three cherry stones (Petter, 2017). He began to feel extremely unwell around 10 minutes later and time-critical medical intervention led to a full recovery. Although amygdalin is stored within the fruit seeds and stones cells, these do not cause any harm unless they are chewed or crushed. When amygdalin comes into contact with the fruit enzymes, hydrogen cyanide is released (Bolarinwa et al, 2015).When chewed or crushed seeds or stones are ingested, the process of hydrogen cyanide release is further exacerbated on contact with enzymes in human natural gut microflora. Symptoms of poisoning can manifest almost immediately, as hydrogen cyanide starts to act on the biochemical pathway of respiration (Sauer et al, 2015). Symptoms of sub-acute poisoning include (Bolarinwa et al, 2015) anxiety, headache, dizziness and confusion. Symptoms of acute cyanide poisoning include a decreased consciousness level (assessed via the Glasgow Coma Scale (GCS) or Alert, Voice, Pain, Unresponsive (AVPU) scale), low blood pressure, paralysis, coma and death. Owing to the propensity of children to swallow fruit seeds and stones unintentionally, it is vital that parents remain aware of the possible consequences of such accidental ingestion and seek medical attention early.