Longevity Briefs: Can This Asian Tree Extract Slow Ageing?

Longevity briefs provides a short summary of novel research in biology, medicine, or biotechnology that caught the attention of our researchers in Oxford, due to its potential to improve our health, wellbeing, and longevity.

The problem:

Ginkgo biloba, also known as the maidenhair tree, is an East Asian tree that produces a compound called ginkgolide B. This compound has a variety of biological effects that may be relevant to ageing, including anti-inflammatory and antioxidant properties, as well as the ability to influence molecular pathways controlling apoptosis – the process in which damaged and diseased cells self-destruct. However, the practical benefits of ginkgolide B require further investigation. In this study, researchers report some impressive effects of ginkgolide B on health and lifespan in mice.

The discovery:

In the study, researchers took 70 female mice and split them into two equal groups. At 20 months of age (roughly equivalent to a 70 year-old human), one group was given regular doses of ginkgolide B, while the other group was given a control treatment. They found that ginkgolide B had a significant effect on lifespan. The median lifespan of the treated mice (that is to say, the age by which half of the mice were dead) was 8.5% higher than that of the control mice. When comparing the average lifespans of the 10% longest-living mice from each group, they found that the longest-lived treated mice survived 5.9% longer than the control mice. In other words, the treatment appeared to boost the maximum age to which the mice tended to live.

The researchers also noted a significant reduction in cancer incidence among the treated mice. Furthermore, those mice that did get cancer lived longer if they were given ginkgolide B, suggesting that the compound both prevents cancer and slows down the disease.

In addition to increased survival rates, ginkgolide B also appeared to come with a variety of health benefits. These included:

• Increased muscle mass, strength and physical performance, including in oestrogen-deficient mice
• Metabolic improvements such as improved sensitivity to the blood sugar lowering hormone insulin and beneficial changes in blood cholesterol levels
• Reduced markers of inflammation and signs of improved immune cell function
• Beneficial changes in the expression of genes related to ageing, suggesting improvements such as better functioning mitochondria (the ‘cellular organs’ or organelles that power the cell) and reduced cellular senescence (the process in which cells stop dividing)

The implications:

Ginkgolide B appears to have some significant health and lifespan benefits in mice and is worth further investigation in humans. One point worth noting is that ginkgolide B treatment in this study was started when the mice were already quite old. This is a good thing, as it suggests that the treatment is still able to have a positive impact even after significant age-related deterioration has occurred, and that it might have an even greater impact if started earlier. Some studies have already investigated the effects of ginkgo extracts in humans, but while they have found the treatment to be safe for most people, there is currently no conclusive evidence that ginkgo treats any health condition.

It’s also important to stress that humans are not going to experience the level of lifespan extension seen in these mice, and indeed are unlikely to experience any lifespan extension at all. The effects of treatments that extend lifespan in animals progressively diminish in longer-lived species. Mice and humans share many fundamental aspects of the biology of ageing, but the relevance and impact of these aspects can differ significantly between the two species, as do the diseases from which we die. For example, mice do not naturally develop Alzheimer’s disease because they simply don’t live long enough. You can also see from the graphs above that about half of the control mice developed cancer within 100 days of starting the experiment, with a total of 75% developing cancer by the end of the study. By contrast, around 40% of humans will get cancer during their entire lifespans. There will always be questions about whether an intervention in mice actually targets ageing, or merely addresses the problems that are specific to whatever strain of mouse is used.