RhododendronThe plant rhododendron belongs to the familyEricaceae which also includes the Heath, and there areabout eight-hundred fifty species which grow worldwide(Turner and Szczawinski, 171-2).
The Heath family is alarge one with so many species, all of the poisonousspecies fall into two of its subfamilies, one of which isthe rhododendron. These cultivated plants occur naturally in temperateregions of the northern hemisphere and in the mountains ofSoutheast Asia. They are located in the Himalayas withseven-hundred species, southwest China, Burma, and in NewGuinea with over three-hundred species (Turner andszczawinski, 172). It has been popular as ornaments ingardens and has led to a major horticultural industry withits widely uses in landscaping. There are twenty-seven species native to NorthAmerica, (Turner,172) and is the state plant ofWashington.
This specific plant is called R. macrophyllumor the Pacific rhododendron (Pojar and Mackinnon, 61). Itforms a shrub layer in forests ranging from shoreline pinegroves to stands of Douglas-fir and western Hemlock up inthe mountains. Usually they are located everywhere fromhomes to freeway sides and also in the forests.
The rhododendron shows a great variety in size,habit, and flower color, colors from white to pink,dark-purple, yellow, red, and orange (McKenzi,1). Theyrange from small shrubs to small trees with evergreenleaves that are leathery. The leaves are short stalked,simple, and alternate, and the flowers are large,bell-shaped, and born in dense clusters. They are bestgrown on acidous soil with a ph of 4. 5 and 6. 5, includedwith lots of moisture and organic material (McKenzie, 3).
The leaves, flowers, pollen, and nectar of manyrhododendron species contain several toxins (Kingsbury,50). These toxins are called grayanotoxins orandromedotoxin, a resinoid carbohydrate (Kingsbury, 51). It is prevalent in the flower nectar, and has causedpoisoning of bees and the honey produced. The symptomsare similar to both humans and all animals. The humancases are that in which children chew the leaves and getthe poison in their system, or when people drink tea madefrom the honey and plant (Abrahams, 2). It has beenreported that animals clip the leaves for boredom or whenthey get hungry, as food is short (U.
S food and drugadmin. , 3). The rhododendron is a beautiful plant which liesoutside homes for decorations. People should become moreaware of its toxicity and should take precautions whenhandling them. GrayanotoxinThe plant rhododendron contains several toxins calledgrayanotoxins. Other well known but former names arerhodotoxin, andromedotoxin, and acetylandrome (U.
S. foodand 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 (Abrahams1). The grayanotoxins cause this intoxication, and thespecific toxins vary with the plant species. Other namesassociated with this disease is rhododendron poisoning,mad hone intoxication or grayanotoxin poisoning. (U.
S foodand drug admin. , 1)The poisoning results from the ingestion ofgrayanotoxin contaminated honey. The other ways that itcan get into your system is if you consume plant parts. Every part of the plant is poisonous, the flowers, nectar,honey, and especially the leaves, which contain more. In humans, symptoms of poisoning occur six hoursafter a dose.
These symptoms include salivation,vomiting, very low blood pressure, loss of coordination,muscular weakness, slow and irregular heartbeat, andcomas, followed by death in extreme cases. (U. S. FDA,2) All organisms such as animals and humans are affectedin the same way. The treatments are to induce vomiting,or perform gastric lavage, replace fluids and maintainelectrolyte balance, monitor heart beat, blood pressureand breathing.
Even though the cases reported have been rare, peoplestill should become aware of this toxin. House pets eatthe plants, children do also, so they should be taught tostay away from these plants.
