The Medicinal Value of the Ginkgo Biloba Plant

The Medicinal Value of the Ginkgo Biloba plant

Abstract
Ginkgo Biloba is one of the longest living species of tree in the world, and a single tree can live for thousands of years (MedlinePlus 2014). From the literature reviewed in this piece, there is sufficient evidence to suggest that the Ginkgo Biloba plant has medicinal value. The improvement of blood flow (Fisher 2009, p. 121) and cognitive and memory disorders (MedlinePlus 2014) are claimed to be the most effective. However, it is also claimed that ingestion of the Ginkgo plant has negative side effects (Chan et al 2011), and some research suggests that its medicinal value is no more effective than a placebo (Han et al 2012).

Introduction
Ginkgo Biloba, also commonly known as Maidenhair Tree (Fisher 2009, p. 120), is a deciduous tree belonging to the Ginkgoaceae family. Almost all species of Ginkgo are now extinct in the wild, but Ginkgo Biloba has been preserved in China and Japan (Fisher 2009, p. 119) as a sacred tree in temple gardens (Bone & Mills 2013, p. 596). Ginkgo is sometimes referred to as a fossil, as it has not changed in over 200 million years and has no known living relatives (Cohn 2013). Ginkgo has also been noted as one of the best-selling herbal supplements in Europe and the U.S (Ehrlich 2010).

Ginkgo Biloba is widely cultivated and has been used in traditional and Chinese medicines for more than 5,000 years (Jang et al 2012 & Jalapour et al n.d). The green leaves of the Ginkgo plant are said to be the most effective, and extracts are used in medications, natural therapies and oriental medicine (MedlinePlus 2014 & Jang et al 2012, p. 421).

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Figure 1: Ginkgo Biloba botanical drawing (Kwant n.d).

Medicinal Value

Jang et al (2012, p.421) claim that extracts of Ginkgo nuts and leaves have been used in traditional oriental medicine. However Bone & Mills (2013, p. 596) claim that whilst Ginkgo nuts are used in traditional Chinese medicine, traditional use of the Ginkgo leaf is not well documented. There has been little evidence to support medicinal benefits of the stem of the Ginkgo plant (Jang et al 2012, p. 421).

Fisher (2009, p.120) states that the Ginkgo plant has anti-inflammatory and anti-oxidant properties, and Bone & Mills (2013, p. 596) further state that Ginkgo acts as a circulatory stimulant, tissue perfusion enhancer and neuroprotective. Whilst the mechanism by which Ginkgo acts is not entirely understood, it can be attributed to the two types of anti-oxidant, organic, chemicals found in the leaves; flavonoids and terpenoids (Nasab et al 2012, p. 677). Fisher (2009, p. 120) claims that Ginkgo’s antioxidant action is comparable to that of Vitamin E, and it’s flavonoids are considered the most powerful antioxidant (Fisher 2009, p. 120). These antioxidant properties also help to fight free radicals, which are harmful molecules found in the human body (Ehrlich 2010). This is further concluded by Bone & Mills (2013, p. 600-610) by stating that previous in vitro and in vivo studies, results showed an inhibition in the formation of free radicals.

According to Ehrlich (2010), the Ginkgo plant improves blood circulation by “opening up the blood vessels and making blood less sticky” (Ehrlich 2010). This is further referenced by Fisher (2009, p. 121) stating that Ginkgo can be effective in the treatment of a number of conditions relating to blood flow, including angina, type 2 diabetes and recovery from cardiovascular surgeries.

However, Han et al (2012) claim that in the case of tinnitus, a condition potentially caused by restricted cerebral blood flow (Bone & Mills 2013, p. 596), the use of the Ginkgo plant is no more effective as a form of treatment than a placebo effect (p. 821). In contrast, Boetticher (2011) claims that the effectiveness of the Ginkgo plant in tinnitus has not yet been proven, but this is likely to be due to an error in clinical trials, rather than the effectiveness of the plant.

Gikgo is most commonly used in elderly patients, focusing on the treatment of mild to moderate dementia (Suter et al 2011, p. 1078) and age-related physical and cognitive disorders (Nasab et al 2012, p. 677). A trial using Ginkgo plant extract was administered daily to elderly patients with age-related mild cognitive impairment, and results showed an improvement in the patients’ concentration, memory retention and quality of life (Suter et al 2012, p. 1086).

Ginkgo is contraindicated in patients who are known to be sensitive to the herb, and extracts containing a significant amount of Ginkgolic acids may produce an allergic reaction (Bone & Mills 2013, p. 617). Some report state that Ginkgo has been linked to some serious side effects, including spontaneous haemorrhaging, post-operative bleeding (Fisher 2009, p. 124) and an increased risk of bleeding following ingestion of Ginkgo (Chan et al 2011, p. 513). Whether prescribed alone, or with anticoagulant drugs, it has been stated that it is not clear whether Ginkgo contributes to haemorrhaging (Chan et al 2011, p. 516). However, Ginkgo is increasingly prescribed alongside anticoagulant drugs and it has been suggested that patients are physicians are generally not aware of the potential adverse reactions (Chan et al 2011, p. 516).

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Table 1: Risk of Hemorrhage Associated with Co-Prescriptions for Ginkgo biloba and Antiplatelet or Anticoagulant Drugs (Chan et al2011, p. 515).

In contrast, Bone & Mills (2013, p. 597) state that there is very little risk associated with Ginkgo and the likelihood of bleeding or interaction with blood thinning drugs is overstated in many publications and not supported by clinical trials. It is further stated that caution should be used when prescribing alongside anticoagulants (Bone & Mills 2013, p. 617).