Indigenous peoples have lived for generations without sophisticated medical treatments; rather, they rely on the land. And while today’s medical advancements are to be heralded, there’s something to be said for those who are able to successfully exploit nature’s healing properties.
Recently, Cassandra Quave and her colleagues at Emory University discovered a compound in the leaves of a common shrub that seems to boost antibiotic effectiveness against MRSA. Quave, a leader in the field of medical ethnobotany—which studies the use of medicinal plans among indigenous and other groups of people—says she was drawn to the potential of American beautyberry given its high medicinal regard among several Native American tribes.
According to Quave, the Alabama, Choctaw, Creek, Koasati, Seminole and other Native American tribes all relied on the American beautyberry for various medicinal purposes. For example, leaves and other parts of the plant were boiled for use in sweat baths to treat malarial fevers and rheumatism. The boiled roots were made into treatments for dizziness, stomachaches and urine retention, while bark from the stems and roots were made into concoctions for itchy skin.
The American beautyberry, or Callicarpa americana, is native to the southern United States. Beyond bearing bright purple berries that are an important food source for many species of birds, extracts collected from the leaves have proven to be effective against MRSA in a recent study.
For the study, Quave’s laboratory identified a compound of interest that belongs to a group of chemicals known as clerodane diterpenoids, some of which are used by plants to repel predators. However, the compound from the leaves didn’t fare well against MRSA—it only slightly prevented the growth of the superbug.
So, the scientists took it a step further and paired the compound with beta-lactam antibiotics to see if the combination would lead to a more fruitful result. Beta-lactam antibiotics are among the safest and least toxic antibiotics currently available, but MRSA has developed a resistance to them. In laboratory tests, however, the beautyberry leaf compound synergized with the beta-lactam antibiotic oxacillin to knock down MRSA's resistance to the drug.
The next step is to test the combination of the beautyberry leaf extract and oxacillin as a therapy in animal models. If those results prove effective against MRSA infections, the researchers will synthesize the plant compound in the lab and tweak its chemical structure to try to further enhance its efficacy as a combination therapy.
“We need to keep filling the drug discovery pipeline with innovative solutions, including potential combination therapies, to address the ongoing and growing problem of antibiotic resistance,” Quave said.
Antibiotic resistance already claims the lives of more than 2 million people per year in the United States, and experts warn that it could prompt a global economic crisis by 2050 if left unchecked. The first generation of antibiotics peaked in the 1940s and 1950s with the mass production of penicillin and streptomycin. These antibiotics were derived from soil microbes, but, by 1960, the scientists kept rediscovering the same antibiotics. So, pharmaceutical companies created synthetic versions, inadvertently driving antibiotic resistance. In recent years, there has been a push from scientists to go back to the beginning and see what nature can provide as the “second generation” of antibiotics. Quave and colleagues’ ethnobotany work is a small part of this race to discover more of nature’s microbes that may yield new drugs.
Photo: The American beautyberry. Credit: Tharanga Samarakoon