Research HighlightsInvestigating How Fatty Acids Produced by Soybeans Could Help Fight Human Diseases
By Carol Brown
Soybeans continue to find their way into products and are often used in remarkable ways. The oil from this versatile plant is replacing petroleum in products such as rubber, plastic, asphalt, and diesel fuel. Scientists are also exploring how the compounds derived from soybeans could be used to benefit human health, including using soy protein isolate as a skin substitute and now possibly using a fatty acid from soybean oil in pharmaceuticals.
North Dakota State University plant pathologist Shaobin Zhong is developing soybeans that produce oil containing a higher level of the fatty acid dihomo-gamma-linolenic acid, or DGLA. The DGLA found in the oil could be used to help fight cancer and aging-related diseases1. The North Dakota Soybean Council has been funding this research since 2020.
“A colleague at NDSU, Dr. Steven Qian, discovered that DGLA has inhibitory effects on various types of cancer cells. Scientific studies with mice showed that DGLA supplementation combined with drug administration reduced cancer tumors1,” Zhong says. “He approached me to see if we could produce enough soybean-derived DGLA for his research. However, sadly he passed away just after we started the project.”
DGLA and gamma-linolenic acid (GLA) are omega-6 essential fatty acids that the human body can produce but in very limited amounts. Small amounts of GLA can be found in a variety of sources including some vegetable oils, says Zhong. But DGLA is extremely rare in nature and found only in trace amounts in animal products. To use DGLA for cancer treatment and other pharmaceutical applications, scientists would need to find new sources for large-scale production.
Although rich in linoleic acid, soybean oil naturally does not contain DGLA because the plant lacks the enzymes for DGLA synthesis. Zhong and his lab are developing soybean plants that produce the enzymes required to make DGLA as well as GLA, increasing the amount in the extracted oil.
“There is a lot of linoleic acid in soybeans. If we could convert some of this to DGLA, it could be a good source for these cancer medications in humans,” explains Zhong. “In the beginning of the project, we created soybean lines with low levels of DGLA, like 2 or 3%. Over time, we’ve increased the levels to around 10%. We also developed soybean lines that produced GLA of up to 30%.”
Since Zhong began this research, he has been approached by Christopher Wiley, at Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University, to explore DGLA in anti-aging therapies as well.
“Since there are many diseases related to aging, finding that DGLA could be used for treatment is promising,” says Zhong. “Dr. Wiley’s lab conducted experiments in mice using pure DGLA from a chemical company, but it is very expensive for experimental use. We are looking to make a cheaper source for people to use in experiments and hopefully someday pharmaceuticals.”
Zhong used two soybean cultivars, Williams 82 and Thorne, to do the genetic transformation, as not all soybean varieties perform the same in this process, he says. The next step in this research will be screening more transgenic plants to develop soybean cultivars that could produce the highest possible amount of DGLA.
“We don’t know how much DGLA we can get in the end, but 10% is still good,” he says. “My collaborators are testing to see if the 10% DGLA-containing oil is effective enough to fight cancer cells or aging-related diseases.”
Zhong also will look at alternatives, such as ways to condense or concentrate the DGLA, if 10% is all that soybeans can produce. He and his colleagues will continue to seek solutions that can assist in the battle against cancer and aging diseases, and the DGLA produced by the transgenic soybean plant may become a contributor to the fight as well.
1 Xu, Yi & Yang, Xiaoyu & Gao, Di & Yang, Liu & Miskimins, Keith & Qian, Steven. (2018). Dihomo-γ-linolenic acid inhibits xenograft tumor growth in mice bearing shRNA-transfected HCA-7 cells targeting delta-5-desaturase. BMC Cancer. 18. 10.1186/s12885-018-5
Dr. Shaobin Zhong is a professor in the Department of Plant Pathology at North Dakota State University. His current research focuses on the use of host resistance to fight against important diseases of cereal crops including wheat and barley, in addition to this project.
Published: Jan 2, 2023
This project was funded by the soybean checkoff. To find research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.