Life Extension Magazine April 2005
Newly Discovered Anti-Aging Effects of Ginkgo Biloba
By Heather S. Oliff, PhD
By Heather S. Oliff, PhD
Treating Erectile Dysfunction
In men, sexual stimulation in the brain causes nitric oxide to be released in cells of the penis. The nitric oxide initiates a chain of events that causes the smooth muscles of the penile arteries to relax so that blood flows into the penis. An increase in blood, which is temporarily trapped in the penis, produces an erection. Considering that an erection requires intact psychological, neural, and vascular responses, it is not surprising that erectile dysfunction affects approximately 50% of all American men between the ages of 40 and 70.16
Ginkgo extract increases the availability of nitric oxide to cells in the penis. It also induces relaxation of vascular smooth muscle in the penis.16 Ginkgo extract may provide a modest benefit to underlying vascular dysfunction, thus helping a man to respond spontaneously to his partner.16 A study at the University of California in San Francisco demonstrated that ginkgo extract was 76% effective in treating male sexual dysfunction associated with the use of antidepressants.17 Ginkgo may thus be a valuable tool in treating erectile dysfunction, particularly of the kind related to use of antidepressants.
Helping to Repair Peptic Ulcers
A peptic ulcer is a lesion or excoriated segment in the stomach lining or duodenum (a part of the intestine near the stomach). Typically, peptic ulcers are treated with drugs that decrease stomach acid or with antibiotics to kill the bacteria Helicobacter pylori, which is thought to cause peptic ulcers. Unfortunately, some H. pylori bacteria are resistant to antibiotics and some peptic ulcers are not caused by H. pylori. A novel treatment for peptic ulcers would be welcome, and an exciting new finding suggests that ginkgo extract may well be such a treatment.
A study in animals found that ginkgo extract could help protect against peptic ulcers and help to repair the ulcerated tissue.18 Rats with experimentally induced duodenal ulcers were treated with ginkgo for 14 days. Ginkgo extract increased superoxide dismutase (SOD) activity in the rats, and SOD is thought to protect against the free-radical damage that is involved in the pathogenesis of ulceration.18 Ginkgo extract improved mucosal repair by increasing the formation of microvilli on the cells in the ulcer. In addition, ginkgo increased levels of prostaglandins that help protect the lining of the stomach and duodenum.18 While needing to be confirmed in humans, these preliminary findings are very promising.
Relief for Arthritis Sufferers
A preliminary study found that ginkgo may benefit people with arthritis. In an animal model of arthritis, scientists found that ginkgo’s anti-inflammatory action was as effective as that of the nonsteroidal anti-inflammatory drugs (NSAIDs) Indocin® and Celebrex®, and better than that of Vioxx®, the popular painkiller that was recently removed from the market because it increases the risk of heart attack and stroke.19 The ginkgo extract was also found to reduce pain. NSAIDs are known to produce gastrointestinal bleeding; by contrast, ginkgo extract prevented gastric lesions.
Administration of ginkgo with the NSAIDs produced an additive response, suggesting that ginkgo administered with NSAIDs might increase their efficacy.19
New Mechanism of Action Discovered
A newly discovered mechanism of action for ginkgo extracts underscores ginkgo’s importance in treating Alzheimer’s disease.20 Alzheimer’s disease involves the progressive deposition of beta amyloid protein (Abeta) in the brain. Abeta forms when an enzyme called beta-secretase cleaves a larger precursor protein called amyloid precursor protein (APP).20 Alternately, an enzyme called alpha-secretase can cleave APP and release a part of the protein known as alphaAPP.20 AlphaAPP is thought to exert a neuroprotective effect and to enhance learning and memory in the brain.20 Scientists discovered that ginkgo extract could induce the metabolism of APP toward the alpha-secretase pathway, thereby causing the release of alphaAPP.20 This important mechanism of action counteracts reports that ginkgo has no effect in Alzheimer’s disease or on learning and memory.
Ginkgo extract’s broad spectrum of pharmacological effects suggests that it may be a valuable tool in promoting a long and healthful life.
The last 18 months have seen the publication of many exciting new studies on the effects of ginkgo extract. The latest clinical trials indicate that ginkgo may improve the mental health and quality of life of healthy older adults and may prevent retinopathy in people with type II diabetes. Two newly completed meta-analyses allowed researchers to conclude that ginkgo extract may be a good treatment option for people with Alzheimer’s disease who cannot take cholinesterase inhibitors, and that ginkgo extract may improve symptoms of intermittent claudication. A review of the literature and pharmacological activity showed that ginkgo extract may combat erectile dysfunction. The latest scientific discoveries indicate that ginkgo may benefit people with ulcers or arthritis. Finally, a newly discovered mechanism of action for ginkgo indicates that it may help preserve mental function even better than originally thought.
Editor’s note: While clinical studies have shown a benefit in taking 240 mg a day of ginkgo, Life Extension still recommends that members take only 120 mg a day. This dose has demonstrated a high degree of safety in large clinical studies.
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