The common name of Ginkgo biloba is the Maidenhair Tree, as their leaves represent that of the common garden fern the Maidenhair Fern. The leaves of the ginkgo tree are unique amongst plants; they are shaped like fans. Typically reaching heights of between 20-35meters and sometimes as high as 50meters, the ginkgo tree is very large. Mature trees seem especially huge because their branches grow to become very broad near the top of the tree. Ginkgo trees are known for their resistance to disease, insects, and also to wind and snow as their roots are deeply embedded into the soil in which they grow. Their sturdiness is reflected by six ginkgo trees that survived the atom bomb explosion of Hiroshima in 1945, whereas virtually all other organisms in the neighboring area were wiped out. Ginkgo trees grow best in well-watered and well-drained environments, such as near river banks. The trees are dioecious, meaning that trees are either male or female, unlike other plants which have both male and female reproductive organs.
Traditionally, the ginkgo tree has numerous uses in medicine and cooking, as well as being culturally symbolic. Although they are an endangered species in the wild, they are commonly cultivated in both China and North America and their products are easily available for purchase. Their resistance to disease and insects as well as their adaptability to urban environments makes them a popular choice for planting along streets.
Use In Medicine
The leaves of the ginkgo tree have been used in traditional medicine for over 1000 years. The extracts contain mainly two types of chemicals, flavonoids and terpenoids, which are believed to have antioxidant characteristics. The extracts are available in capsule, tablet, or liquid forms, but dried leaves of the ginkgo themselves can be used for tea. Ginkgo is used for treating numerous medical conditions, such as dementia, tinnitus, intermittent claudication, and memory impairment.
Dementia is a medical condition where the patient suffers a serious loss of mental ability, such as Alzheimer’s disease. Ginkgo can delay or prevent the effects of dementia but not reverse them. It improves blood flow to the brain, which improves the patient’s cognitive functions such as thinking and learning. Other improvements can be seen in daily activities and social behavior, as well as decreased levels of depression. However, controversy surrounds the effectiveness of ginkgo as a treatment for dementia as a study in 2008 showed that ginkgo is no more effective than placebo drugs, suggesting that perhaps the currently believed effects that ginkgo have on dementia were initially a result of the placebo effect.
The action of ginkgo extracts improving blood circulation have also been shown to treat other medical conditions, such as tinnitus, a condition in which the patient suffers from perceived sounds in their ears even though no sound is coming from the environment around them, and intermittent claudication, which is muscle pain in the calves causing difficulty in walking amongst patients.
Ginkgo extract also improves memory, earning its nickname as the “brain herb”. Ginkgo has been found to help with aiding memory caused by both diseases such as Alzheimer’s and also by natural causes such as aging. It has also shown to improve the attention span of healthy people.
The seeds of the ginkgo tree are used in some traditional Asian cuisines. The seeds are sometimes said to be inedible, but this may be because of their unappealing vomit-like odor they produce when they fall from the trees, and also from the fact that over-consumption of the seed can in fact cause poisoning, more of which will be discussed later. However, the Chinese and Japanese use ginkgo seeds in their cuisine as a delicacy. They are added to congees in Chinese cuisine often served at special occasions such as Chinese New Year, and in Japanese cuisine they are a common ingredient in the steamed egg custard dish chawanmushi amongst many other dishes that include ginkgo seeds.
Although used to treat a vast number of medical conditions, like any other treatments, ginkgo extract can have side effects on patients. Side effects can range from common symptoms such as nausea, diarrhea, dizziness, headache, and an upset stomach, to more serious side effects such as but are not limited to bleeding, paralysis, slurred speech, and blurred vision. As this illustrates, there are quite a number of precautions to be considered of the intake of ginkgo. Children and pregnant ladies should abstain from ginkgo, and individuals with epilepsy or diabetes are some of the few that are advised against taking it. The seed which was earlier discussed as a culinary item can cause poisoning, especially in the raw form, because of the chemical ginkgotoxin.
Other than being the national tree of China, the ginkgo leaves are symbolic in the Urasenke school of the Japanese tea ceremony. In other areas of Japan, the tree is also hugely popular as the official tree of many cities, towns, villages, and even university campuses. The popularity of the tree may be owed to its significant status in Buddhism and Confucianism, the dominant ideologies of China and Japan, making it a widely planted tree in Korea as well.