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Study finds beneficial effects of aloe (4/23/97)

Aloe, a plant used as a folk remedy since the time of Cleopatra, has shown beneficial health effects in test animals at The University of Texas Health Science Center at San Antonio.

The major findings of a four-year study were a prolongation of life span in the animals, a decrease in the occurrence and severity of kidney and heart problems, and fewer tumors common to older rats of the breed studied.

The recently completed aloe aging study, performed by Health Science Center faculty and funded by Aloecorp of Harlingen, is the first documented, long-term study of the effects of ingested aloe. San Antonio researchers administered gel from the leaves of the Aloe barbadensis plant to laboratory rats over their entire life. Special care was taken in the study to avoid complications due to infection by housing the rats under specific pathogenic-free conditions.

"This is the first study ever performed using the long-term feeding of aloe," says the study's program director, Byung Pal Yu, PhD, professor of physiology. Dr. Yu, having worked with aloe for several years, previously identified and patented a potent antioxidant extracted from the plant. "Aloe gel has many active ingredients, only two of which - an antioxidant and an anti-inflammatory agent (also identified at the Health Science Center) - have been identified," Dr. Yu says.

"There has never been much scientific backup for the ingestion of aloe, although people worldwide use it for medicinal purposes including burns, digestion and as a cathartic (to cause the bowels to move)," says the study's principal investigator, Jeremiah T. Herlihy, PhD, associate professor of physiology. "More people in the world take the gel internally than use it for a skin treatment," he points out, "and we wanted to begin to document what the effects actually are."

This study used 360 "Fisher 344" rats, a breed which has been used in numerous aging studies both at the Health Science Center and worldwide. Consequently, researchers know a lot about how these animals age and what causes them to eventually die.

Following a seven-month preliminary study, the main study was begun. A control group was fed normal rat chow. A second group received normal rat chow with an addition of 1 percent aloe from fresh gel that had been dried. A third group ate normal rat chow containing 1 percent charcoal-filtered aloe that had been dried. A fourth group ate normal rat chow with no additions, but drank water with .02 percent aloe added.

According to pathologist Yuji Ikeno, MD, PhD, assistant professor of physiology, who examined the rats after death, the pathological profiles of the aloe-fed rats differed significantly from the control group in several ways. "The chronic nephropathy (kidney disease) usually found in the Fisher 344 rats at the end of their life span was reduced and so was the cardiomyopathy (disease of the heart muscle)," he reports. He also found a reduced incidence of atrial thrombosis (clot formation in the atrium of the heart), which causes acute heart failure, and a trend suggesting a slightly lower incidence of neoplastic disease (tumors). "Multiple causes of death were reduced, suggesting that the disease burden was lighter in the aloe-fed rats," he says.

The investigators hope to do additional studies in the near future. "We still need to determine the optimum dose of aloe and identify the active ingredients responsible for the observed benefits of aloe," says Dr. Yu.

At present, the U.S. Food and Drug Administration has approved the use of aloe only as a cathartic, but the researchers have laid the groundwork to help document and describe the beneficial effects of ingested aloe in mammals, including humans.

Contact: Mike Lawrence (210) 567-2570