RhododendronTheplant rhododendron belongs to the family Ericaceae which also includes theHeath, and there are about eight-hundred fifty species which grow worldwide(Turner and Szczawinski, 171-2). The Heath family is a large one with so manyspecies, all of the poisonous species fall into two of its subfamilies, one ofwhich is the rhododendron. These cultivated plants occur naturally in temperateregions of the northern hemisphere and in the mountains of Southeast Asia. Theyare located in the Himalayas with seven-hundred species, southwest China, Burma,and in New Guinea with over three-hundred species (Turner and szczawinski, 172).
It has been popular as ornaments in gardens and has led to a major horticulturalindustry with its widely uses in landscaping. There are twenty-seven speciesnative to North America, (Turner,172) and is the state plant of Washington. Thisspecific plant is called R. macrophyllum or the Pacific rhododendron (Pojar andMackinnon, 61).
It forms a shrub layer in forests ranging from shoreline pinegroves to stands of Douglas-fir and western Hemlock up in the mountains. Usuallythey are located everywhere from homes to freeway sides and also in the forests. The rhododendron shows a great variety in size, habit, and flower color, colorsfrom white to pink, dark-purple, yellow, red, and orange (McKenzi,1). They rangefrom small shrubs to small trees with evergreen leaves that are leathery.
Theleaves are short stalked, simple, and alternate, and the flowers are large,bell-shaped, and born in dense clusters. They are best grown on acidous soilwith a ph of 4. 5 and 6. 5, included with lots of moisture and organic material(McKenzie, 3).
The leaves, flowers, pollen, and nectar of many rhododendronspecies contain several toxins (Kingsbury, 50). These toxins are calledgrayanotoxins or andromedotoxin, a resinoid carbohydrate (Kingsbury, 51). It isprevalent in the flower nectar, and has caused poisoning of bees and the honeyproduced. The symptoms are similar to both humans and all animals.
The humancases are that in which children chew the leaves and get the poison in theirsystem, or when people drink tea made from the honey and plant (Abrahams, 2). Ithas been reported that animals clip the leaves for boredom or when they gethungry, as food is short (U. S food and drug admin. , 3). The rhododendron is abeautiful plant which lies outside homes for decorations.
People should becomemore aware of its toxicity and should take precautions when handling them. Grayanotoxin The plant rhododendron contains several toxins called grayanotoxins. Other well known but former names are rhodotoxin, andromedotoxin, andacetylandrome (U. S. food and drug admin.
, 1). They are included in almost all ofthe species rhododendron. The name of the disease is honey intoxication, whichis caused by the consumption of honey produced (Abrahams 1). The grayanotoxinscause this intoxication, and the specific toxins vary with the plant species. Other names associated with this disease is rhododendron poisoning, mad honeintoxication or grayanotoxin poisoning.
(U. S food and drug admin. , 1) Thepoisoning results from the ingestion of grayanotoxin contaminated honey. Theother ways that it can get into your system is if you consume plant parts.
Everypart of the plant is poisonous, the flowers, nectar, honey, and especially theleaves, which contain more. In humans, symptoms of poisoning occur six hoursafter a dose. These symptoms include salivation, vomiting, very low bloodpressure, loss of coordination, muscular weakness, slow and irregular heartbeat,and comas, followed by death in extreme cases. (U. S.
FDA,2) All organisms suchas animals and humans are affected in the same way. The treatments are to inducevomiting, or perform gastric lavage, replace fluids and maintain electrolytebalance, monitor heart beat, blood pressure and breathing. Even though the casesreported have been rare, people still should become aware of this toxin. Housepets eat the plants, children do also, so they should be taught to stay awayfrom these plants.
