By Dr. Joseph Mercola,
For decades, ginkgo proponents have sworn by the supplement for its ability to sharpen memory and improve overall brain function. New research expands on those attributes with evidence showing that the ancient Chinese herbal has another claim to fame: Although extracts have been made from the dried leaves of the plant,1 extracts from the seeds (aka "nuts") were found to be useful as a topical solution for acne.
What scientists have already ascertained about ginkgo sets it apart from other trees for several reasons. The deciduous ginkgo tree itself is called a "living fossil." Incredibly hardy, it has unique, fan-shaped leaves that spread an attractive canopy of shade.
As the oldest-known tree on Earth, several other impressive attributes include its ability to grow as high as 120 feet and live more than 1,000 years.2 In fact, some trees growing in China are claimed to be more than 2,500 years old.3 Also known as maidenhair tree, the name ginkgo has an intriguing significance, as the Japanese word "gin" means "silver" and "kyo" translates to "apricot."4
Fruit, or more precisely, the "naked seed" of the gymnosperm isn't enclosed in a ripened fruit like flowering plants (angiosperms) are.5 They do resemble apricots, but unlike apricots, ginkgo fruits should not be eaten, nor would one want to — the smell has been compared to smelly gym socks or even vomit,6 and compounds in the seeds are said to be toxic.
Still, the supplements are some of the most popular among any on the market, typically sold as a tablet, capsule or liquid extract. Medical News Today notes:
"Ginkgo extracts — mostly from the tree's leaves — are often present as the key ingredients in herbal supplements. However, although experimental studies have suggested that ginkgo may help treat many conditions, from depression to Alzheimer's to diabetes, its actual effectiveness and safety remain debatable."7
Ginkgo Biloba for Blemish-Free Skin
Traditional uses have included ginkgo for intestinal parasites, treating arthritis and helping to soothe chilblains, which describes the itching, blistering and red patches caused by the inflammation of small blood vessels in response to cold, but not freezing air,8 and may be related to Raynaud's syndrome.9
In looking for new solutions for dealing with skin infections due to bacterial pathogens, Xinyi Huang, a researcher at Emory University in Atlanta, along with her colleagues examined ginkgo leaves to verify results from a text written by ancient researcher Li Shi-Zhen, circa 1590 A.D.
Known as Ben Cao Gang Mu10 and touted as the Chinese Materia Medica,11 a preparation made from ginkgo seeds was recommended as an antibacterial. Huang, whose early experience with ginkgo came from eating the seeds or nuts, described her first taste in Cantonese soup as "really distinct — a little bit bitter but also sweet."12 She wanted to conduct her own experiments on them. According to Medical News Today:
"In laboratory tests that they conducted on 12 different strains of bacteria … Using statistical analysis, Huang and colleagues also observed a positive correlation between the antimicrobial properties of the ginkgo seeds and their richness in a substance called ginkgolic acid C15:1."13
The scientists' work, published in Frontiers in Microbiology,14 involved testing ginkgo leaves, as well as the seed kernels and seed coats, immature seeds, branches and other plant extracts, on six pathogens known to cause skin and soft tissue infections (SSTIs), some life threatening. Several were alleviated, including:
- Staphylococcus aureus, which is common and sometimes responsible for multidrug-resistant MRSA15
- Cutibacterium acnes, which can cause acne vulgaris, blepharitis, dandruff and psoriasis16
- Streptococcus pyogenes, which can cause impetigo, erysipelas and necrotizing fasciitis17
The extraction methods used — ethanol maceration, water sonication, water decoction and oil infusion — proved to influence the effectiveness, which was also influenced by the plant parts and plant strains used.
Ethanol extracts on the seeds proved most effective. However, the researchers also noted that the ginkgolic acid may have played a large part in ginkgo's inhibitory effect on bad bacteria.
Studies Show What Ginkgo Can Do for Your Brain
So what are the active ingredients in ginkgo? According to studies, the leaf and seed extracts contain terpenoids, flavonol glycosides (principally quercetin and catechin) and proanthocyanidins, which are considered to be responsible for the pharmacological effects.18,19
Ginkgolides and bilobalides are terpenoids unique to ginkgo, which as a species is the only surviving species from the Ginkgoaceae family.20 According to animal studies, ginkgo as a whole has exhibited important mechanisms that may explain some of the positive therapeutic outcomes, as it was found to:
- Inhibit platelet-activating factor, which results in blood coagulation inside arterial walls, to keep plaque from forming21
- Enhance nitric oxide (NO) production in vessels, which promotes healthy endothelial function and subsequent effect on peripheral and cerebral blood flow22
- Initiate synaptosomal uptake of dopamine to improve cognitive function23 and 5-hydroxytryptamine (serotonin),24 a neurotransmitter known for mobilizing your brain and body for action, linked to positive effects on cognition and attention
- Modulate different neurotransmitter systems, such as inhibiting monoamine oxidase A, an enzyme that can eliminate norepinephrine, serotonin and dopamine from your brain
- Exert free radical-scavenging activity, as it has neuroprotective and antiapoptotic properties, such as inhibiting amyloid-β neurotoxicity and protecting against hypoxic challenges, and may be particularly beneficial for Alzheimer's25
As a supplement, ginkgo has elicited a lot of discussion and even controversy regarding its therapeutic capabilities, but the study lists a number of ways researchers found it to be viable, which is why their data support its use for patients with dementia and schizophrenia specifically.
In their scrutiny of 1,109 clinical publications to verify using ginkgo, the researchers reported its use as "equal" to that of a drug called donepezil,26 used to treat dementia and accompanying memory loss, including severe cases of Alzheimer's, in two different trials.
In short, the study concludes, "Available evidence is sufficient to support the use of ginkgo biloba in patients with dementia and as an adjunctive therapy in schizophrenic patients."27 However, promising results for its use of other neuropsychiatric conditions, such as attention deficit hyperactivity disorder (ADHD), anxiety, depression, addiction and autism were not verified.
Other uses for ginkgo have included to improve vision, sexual function and reproductive health,28tinnitus29 and anxiety.30 One study of 332 subjects found that people with normal tension glaucoma experienced improvement after taking 80 milligrams of ginkgo leaf extract in tablet form twice daily.31
How Has the Ginkgo Tree Managed to Survive All These Millennia?
An interesting paradox regarding the ginkgo tree is that its genetic composition includes both resistance and tolerance of insects and other predators. At the same time, there's evidence that the tree was food to certain dinosaur species.
Teris A. van Beek's book "Ginkgo Biloba"32 notes that ginkgo trees may have proliferated due to the "rotting flesh" smell serving to attract animals to eat the seeds, then defacate intact nuts. A BBC article may help explain the significance of the findings of a 2016 study published in GigaScience:33
"Its resilience is legendary: it was one of the few living things to survive the atomic bomb blast in the Japanese city of Hiroshima in 1945. A ginkgo is known to produce chemicals that are unpalatable to the insects that try to eat it, and will counter the fungi and bacteria that attempt to attack it.
Researchers can now more easily identify the mechanisms that drive these capabilities. The specific species sequenced in the study … reveals the tree's genome to be huge, comprising some 10.6 billion DNA 'letters.' By way of comparison, the human genome contains just three billion letters.
Written in the Ginkgo's DNA code are roughly 41,840 predicted genes, the 'templates' that the tree's cells use to make the complex protein molecules that build and maintain the organism."34
What to Do With the Research, and Cautionary Notes
Huang is quick to add a warning regarding ginkgo consumption, whether it's the leaves or seeds. The cautionary note stems from the fact that the study's first author, François Chassagne, stressed that concentrated ginkgolic acid C15:1 is actually toxic to the skin itself, which is ironic since ginkgo extracts at other concentrations were found to be beneficial for skin.
However, ginkgosides are such powerful flavonoids that they can positively affect even the smallest microcapillaries, leading to widespread benefits on all of your body's organs, especially your brain.35
Huang adds that even though she ate cooked ginkgo seeds when she was a child, her parents always emphasized the importance of eating no more than five at a time. The original Ben Cao Gang Mu says to eat them sparingly, as well.
As is usually the case, the scientists involved in the featured study say they hope their research will result in the development of drugs based on ginkgo that will be even better at combating harmful bacteria. According to Chassagne:
"One possible strategy in the search for new antibiotics would be to investigate ways to modify the structure of the particular ginkgolic acid tied to the antibacterial activity, to try to improve its efficacy and also to reduce its toxicity to human skin cells."36
Whenever you take any supplement, it's important to listen to your body, and that's just as true with ginkgo biloba. While it may offer brain and skin benefits, and more besides, if you experience unpleasant symptoms, you might be better off avoiding it or finding another alternative.
Symptoms people have noted include a mild upset stomach or slight headaches that occur within a few days of taking ginkgo supplements. In cases where individuals took large doses, the symptoms were more intense and included episodes of dizziness, diarrhea and nausea. Seek advice from your doctor if any of the above symptoms occur.37
People with epilepsy should not take ginkgo as it may cause seizures, nor should pregnant and breastfeeding women.38 In addition, people who are particularly susceptible to poison ivy and other such plants should avoid ginkgo due to the long-chain alkylphenols in the leaves, making it more of an allergen.39