Aging is considered to be a biological process that is subject to metabolic control. Not everyone ages in the same way, and the reasons for this are not yet clear, even though the process has been intensely investigated by those seeking to understand it better. A team of scientists in the Department of Biological Sciences at Louisiana State University has now published a landmark study showing that a botanical extract can extend longevity in roundworms by improving their metabolic health.
Although the roundworms (Caenorhabditis elegans) may not appear to have much in common with humans, the investigation supports the results of previous work involving mice, which was conducted at LSU’s Pennington Biomedical Research Center under Professor Jacqueline Stephens.
“The reason this study made so much sense to do in worms is because worms live for only about three weeks, so in a month or two, we had definite results,” said Bhaswati Ghosh, LSU student and lead author of the recently published study.
Both the initial study on mice, and the current study on C. elegans, investigated how the consumption of Artemisia scoparia (an extract named SCO) affected the laboratory organisms. Commonly known as wormwood, A. scoparia is an aromatic herb that is widely distributed across Asia. It is a member of the sunflower family, and an important plant in traditional Chinese medicine. It is known to have many bioactive constituents, including flavonoids, coumarins, phenolic acids and terpenoids.
In the lab of Professor Adam Bohnert, the researchers made an extract from the plant’s leaves and fed worms with this in various doses. They found that the worms fed the highest, and second-highest doses, showed immediate improvement in their metabolic health. They showed heightened levels of unsaturated fat, rather than accumulating saturated fat, which is not as healthy. The treated worms lived 40 percent longer than the untreated worms.
Although the worms that received the extract grew fat and became less mobile, they also became healthier and more resistant to stress. The researchers found that SCO helped convert unhealthy fat stores into healthy fat stores in the worms’ bodies. These findings, published in the Journal of Gerontology, suggest that diet is an important factor that can influence aging at a cellular level. The research indicates that the extract from Artemisia scoparia can activate many pro-longevity pathways in the body, and effectively turn on multiple genes involved in regulating lifespan.
“Until recently, it wasn’t really known how aging could be modified through diet, or how core metabolic signaling pathways influence longevity,” said Bohnert. “What we’ve been able to show is that a natural extract can come in and influence these pathways in much the same way as a genetic mutation would.”
The finding that a dietary supplement (SCO) can have such a significant effect on longevity suggests that we have a certain amount of control over our own aging.
“Importantly, it gives us a therapeutic standpoint,” Bohnert said. “We know age is the primary risk factor for many diseases, such as cancer and cardiovascular disease, but if you think of aging as a treatable disease, you can actually treat many diseases at once.”
The worms that showed the greatest improvement in lifespan were fed the A. scoparia extract during the time before they reached reproductive maturity. However, Bohnert’s team also observed significant effects in worms treated for the first time in middle age. Instead of a 40 percent increase in lifespan, these worms still managed to live about 20 percent longer.
This result is important because it emphasizes the important connection between metabolic health, fat regulation and longevity. The worms that benefited from the SCO treatment not only lived longer, but also became fatter. This indicates that the presence of fat may enhance some aspects of physiological health in older age, as long as it involves healthy, unsaturated fats.
“Usually people think of fat as ‘bad,’ but in these cases, it seems good, and actually pro-longevity,” said Bohnert. “Artemisia scoparia could have some exciting potential as a dietary supplement.”
“Also, the simple fact that an organism is short, fat and slow-moving does not necessarily qualify it as in poor health,” Ghosh added. “These phenotypes must be considered in the full context of other parameters, including lifespan.”
Artemisia scoparia extract is not currently recommended for humans to take as a life-extending dietary supplement, and there is no understanding of what would be a safe or effective dosage. However, the properties of the extract do seem to have had significant impacts. The researchers also investigated the effects of extracts from several other, related plant species, but only observed positive effects on fat regulation and longevity with the A. scoparia extract.
The study authors conclude that the A. scoparia extract is a natural product that can modify fat regulation and benefit longevity by altering core metabolic parameters. They propose that natural products like this may provide a means to extend animal lifespan and promote healthy aging.