Underappreciated avocado husks "a gold mine" of nutrients

22 Aug 2017 --- Scientists have reported that avocado husks, traditionally the least appreciated part of an avocado, could undergo a trash-to-treasure transformation due to the fact that they are full of a previously unrecognized array of chemical compounds. In a first-of-its-kind study, scientists report that avocado seed husks are hidden gold mines of compounds that could eventually be used to treat a host of debilitating diseases, as well as to improve the allure of cosmetics, perfumes and other consumer goods.

The results of the researchers’ work were presented on 21 August at the 254th National Meeting & Exposition of the American Chemical Society (ACS). ACS, the world's largest scientific society, plans to hold the meeting there until 24 August and it is set to feature nearly 9,400 presentations on a range of science topics.

Important compounds
Some edible oil manufacturers extract avocado oil from the seeds, but they remove the husk surrounding the seed and discard it before processing. Debasish Bandyopadhyay, Ph.D., and his students Valerie Cano, Orlando Castillo, Daniel Villicana and Thomas Eubanks at the University of Texas Rio Grande Valley tried to find out more about what manufacturers are throwing away when they discard these seed husks.

The researchers ground about 300 dried avocado seed husks into 21 ounces of powder. After additional processing, the powder yielded about three teaspoons of seed husk oil and slightly more than an ounce of seed husk wax. Using gas chromatography-mass spectrometry analysis, the research team found 116 compounds in the oil and 16 in the wax. Many of these compounds do not appear to be found in the seeds themselves.

Among the constituents in the oil was behenyl alcohol (also known as docosanol), an important ingredient used in antiviral medications; heptacosane, which might inhibit the growth of tumor cells; and dodecanoic acid, which increases high density lipoprotein (known as HDL) and, as a result, could reduce the risk of atherosclerosis.

In the wax, the researchers detected benzyl butyl phthalate, a plasticizer used to promote flexibility in numerous synthetic products from shower curtains to medical devices; bis(2-butoxyethyl) phthalate, which is used in cosmetics; and butylated hydroxytoluene (BHT), which is a food additive.

From waste to gem
“It could very well be that avocado seed husks, which most people consider as the waste of wastes, are actually the gem of gems because the medicinal compounds within them could eventually be used to treat cancer, heart disease and other conditions,” says Bandyopadhyay of the findings’ exciting potential implications. “Our results also suggest that the seed husks are a potential source of chemicals used in plastics and other industrial products.”

In all, nearly 5 million tons (4.5 billion kg) of avocados are produced worldwide annually, according to the ACS press release. Americans consume almost 1.9 billion pounds (862 million kg) each year, the Hass Avocado Board reports. In most cases, the “meat” or flesh is eaten, and the seed is tossed in the trash.

In the future, Bandyopadhyay says his team will modify several of these natural compounds so that they can be used to create better medications with fewer side effects.

The study by Bandyopadhyay and his team is the latest to find potential serious health benefits in avocado ingredients. Avocado seeds have previously been found to potentially prevent listeria, a foodborne bacterial illness. Meanwhile, avocados have already been linked to combating metabolic syndrome and leukemia.