Ginkgo Biloba May Boost Mood

How Ginkgo Affects Mood

Some of the major bioactive phytochemicals in ginkgo extract work as monoamine oxidase inhibitors (MAOIs). These phytochemicals block the actions of both isoforms of monoamine oxidase (MAO-A and -B types).

Monoamine oxidase is an enzyme that catalyzes the breakdown of neurotransmitters such as serotonin, dopamine, and norepinephrine in the brain.

By blocking the action of monoamine oxidase, ginkgo extracts increase the activities of monoamine neurotransmitters in the brain.

However, ginkgo does not increase the activity of only serotonin but also increases the activities of other monoamine neurotransmitters. This non-selective inhibition of monoamine oxidase can result in certain side effects. Furthermore, this non-selective inhibition is also irreversible because it deactivates and stops the functioning of monoamine oxidase permanently.

Usually, it takes the body about 14 days to replace monoamine oxidase and resume its functions.

Depression is basically caused by low levels of one or more neurotransmitters in the brain especially serotonin and dopamine. These brain chemicals are responsible for signal transmissions between the neurons.

When the level of one or more of these neurotransmitters becomes very low in the brain, it disturbs the normal transmission of nerve impulses between neurons. This results in disruptions in neuronal communication and, therefore, brain functions.

To remove these disruptions and treat depression, ginkgo extract restores the levels of serotonin in the brain.

Furthermore, ginkgo improves blood circulation in the brain. With increased oxygen flow to the brain, neurons, and indeed all kinds of brain cells are well-nourished and kept working optimally.

What is Ginkgo?

Ginkgo (Ginkgo biloba) is a tree native to Asia especially China and Japan.  It is one of the oldest trees in the world dating back to about 270 million years ago.

Ginkgo, also known as the maidenhair tree, has been cultivated in Asia for centuries for various purposes especially in the dishes of different cultures and as a remedy in traditional medicine.

Now a widely used herb around the world, even in the US, ginkgo has been shown to improve memory and relieve headaches, ringing in the ears, vertigo, loss of concentration, disturbances in mood, and hearing disorders.

By increasing the flow of blood in the brain, ginkgo also improves brain function. Specifically, it helps the transport of oxygen to brain cells and enhances their performance. This is one reason why ginkgo has been found to be effective in the treatment of neurodegenerative diseases such as dementia and Alzheimer’s disease.

Usually, Ginkgo biloba extract is preferred to the whole leaf powder. This is because the extract is properly standardized to a specific ratio of certain active phytochemicals.

This also means that the extract of better quality than the powder and that it provides a better therapeutic profile.

The two main groups of phytochemicals found in ginkgo extract are:

• Terpene lactones
• Ginkgo-flavone glycosides (flavonoids)

Most of the ginkgo’s medicinal properties are due to the actions of these two groups of chemicals.

Other useful phytochemicals contained in the extract are proanthocyanidins, alkylphenols, simple phenolic acids, 6-hydroxykynurenic acid, 4-O-methylpyridoxine, and polyprenols.

The recommendation for a standardized ginkgo extract is that it contains at least 24% glycosides and 6% terpene lactones. However, most ginkgo extracts available in the market contain less than this specified standard.

Quercetin, kaempferol, and isorhamnetin are the three primary and important ginkgo-flavone glycosides (flavonoids) found in ginkgo extract.

In a 2000 study published in The Journal of Pharmacy and Pharmacology, kaempferol was identified as one of the neuroprotective phytochemicals in ginkgo extract. Kaempferol was also identified as a monoamine oxidase inhibitor and the results of this study established the antidepressant benefit of this compound in animal models.

There are 5 different types of ginkgolides: A, B, C, J, and M. Each of these ginkgolides differ in degree of potency. Ginkgolide B is the most active of them.

It is unlikely that a single phytochemical in ginkgo is responsible for its antidepressant properties. Rather, it is more likely that its antidepressant effect is as a result of the addictive antidepressant potentials of multiple phytochemicals in the herb.

Supplementation, Contraindications, and Warnings

Ginkgo is available in different forms including tablets, capsules, tinctures, and herbal tea.

The recommended dosages of standardized ginkgo extracts are between 80 mg and 240 mg taken daily in two or three divided doses. The daily dose can be divided into 80 mg taken in the morning followed by another 80 mg in the afternoon after lunch.

For the tincture, between 3 ml and 6 ml (containing 40 mg ginkgo extract per ml) of the extract should be taken two to three times a day.

To prevent insomnia, the extract should not be taken in the evening especially before you intend to go to bed.

Ginkgo treatment for depression can take as much as 12 weeks or longer. While some people report improvements earlier than 12 weeks, for others, it may be a little longer for the therapeutic benefits to manifest.

The use of ginkgo extract should not be suddenly stopped or it can cause a withdrawal syndrome. The abrupt withdrawal of the extract is not advised even after the patient has fully recovered. A gradual and steady dose tapering is recommended to desensitize the body to the herb.

Minor side effects which include stomach upset, headache, dizziness, constipation, and allergic skin reactions are associated with the use of ginkgo extract especially when taken orally.

Since ginkgo is a blood thinner, it can increase the risk of internal bleeding. Therefore, ginkgo should not be used with other known blood thinning and antiplatelet medications such as aspirin and warfarin. Patients who have recently undergone surgery are especially advised not to take the supplement.

Those who are allergic to poison ivy, poison oak, poison sumac, mango rind, or cashew shell oil may also develop an allergic reaction to ginkgo.

To avoid complications during pregnancy, pregnant women should stay off ginkgo as it may result in early labor or abnormal bleeding during delivery.

Ginkgo may also increase the risk of seizures in patients suffering from epilepsy.

Using ginkgo along with other antidepressants such as MAOIs and SSRIs (selective serotonin reuptake inhibitors) will increase the risk of serotonin syndrome which can be a fatal condition.

Selective serotonin reuptake inhibitors are antidepressant medications that inhibit the reuptake of serotonin into the presynaptic cell thereby increasing the extracellular levels of the neurotransmitter.

Studies on Ginkgo for Depression

In 2000, a study published in the journal, Human Psychopharmacology: Clinical and Experimental, investigated the effects of Ginkgo biloba extract on mood and activities of daily life in some elderly volunteers.

5028 participants were recruited for this study. 1000 participants were given 120 mg/day Ginkgo biloba extract while the others were given a placebo.

The study used the B-ADL (activities of daily living) Scale and Line Analogue Ratings Scales for assessing both mood and sleep. These assessments were completed at the end of each month for the 4-month duration of the study.

Positive changes in mood and sleep were observed in participants who were given the extract compared to those placed on placebo. This result suggests that ginkgo extract is beneficial in improving the mood of during depression even in the elderly.

Another 1996 study published in the journal, Alternative Medicine Review examined the efficacy of Ginkgo biloba extract in 40 patients suffering from depression.

The 40 participants recruited for the study suffered from mild to moderate cerebral dysfunction combined with episodes of depression. They had all been previously with other antidepressant medications with no improvement. These medications were continued through the course of the study.

The patients were randomly grouped into two, with one group receiving 80 mg of ginkgo extract three times a day, and the other group receiving a placebo.

The study made use of the Hamilton depression scale to assess the severity of depression.

After 4 weeks, the severity of depression had decreased by 50% in the group receiving ginkgo extract compared to the smaller (less than 10%) decline in the placebo group.

As much as 68% reduction in severity was observed in the group given the extract after 8 weeks while there was still less than 10% improvement in the placebo group.

A 2006 study published in the journal, Biology and Pharmaceutical Bulletin, investigated the antidepressant effects of Ginkgo biloba extract in behavioral rodent models (rats and mice).

The study made use of two behavioral models: the forced swimming test (FST) in rats and tail suspension test (TST) in mice. Both tests were used to score depression in these animals.

At a dosage of 10 and 50 mg/kg body weight of ginkgo extract for 14 days, the immobility time in the FST was found to have been greatly reduced. Then at a dosage of 50 and 100 mg/kg body weight of ginkgo extract, immobility time in the TST was significantly decreased.

The reduction in the scores for these tests indicated that Ginkgo biloba extract had an antidepressant effect in these rodents.

A similar study was published in a 2007 edition of the journal, Phytotherapy Research. This study investigated the antidepressant and anti-stress effects of a lipophilic extract of Ginkgo biloba leaves.

The effects of this lipophilic extract on depression and stress were observed in rats. A behavioral despair test and a learned helplessness rodent model of depression were used in the study.

At a dosage of between 50 and 100 mg/kg of ginkgo extract, there was significant antidepressant activity in the behavioral despair test and learned helplessness rodent model of depression.

This result suggested that the lipophilic extract of Ginkgo biloba has significant antidepressant effects.

Depression is known to be one of the common symptoms of sclerosis. In 2006, a New York journal, Explore, published a study that examined the effect of Ginkgo biloba extract on functional measures in multiple sclerosis.

In this double-blind, placebo-controlled study, 22 participants were randomly divided into two groups. One group received 60mg of Ginkgo biloba extract for 4 weeks while the other group received a placebo.

The result of the study showed significant improvement in patients who received the extract compared with those who received a placebo. The indices of the Center for Epidemiologic Studies of Depression Scale (CES-D) were found to increase after treatment in the group receiving Ginkgo biloba extract.

No adverse effects were reported in the study.