Detailed review of plant natural products to combat antibiotic-resistant pathogens

Review by Emily Henderson, Bachelor of ScienceNovember 12, 2020

Scientists have put together the first comprehensive review of plant natural products that play a role in antibacterial activity to help guide in the search for new drugs to combat antibiotic-resistant pathogens.

Chemistry review Presented research by researchers at Emory University. It contains 459 botanical natural products that meet strict criteria for demonstrating antibacterial activity.

This review has also been deposited on the Pew Charitable Trust-sponsored Shared Platform for Antibiotic Research and Knowledge (SPARK).

We hope that chemists and pharmacological researchers will use our reviews as a guide to delve deeper into the promising potential of many plant compounds... “

Cassandra Quave, Principal Research Author and Associate Professor, Center for Human Health Research, Emory Health Sciences

Quave belongs to the Department of Dermatology, Emory University School of Medicine. Quave is also a member of the Emory Antibiotic Resistance Center.

According to the US Centers for Disease Control and Prevention, at least 2.8 million people in the United States get antibiotic-resistant infections each year, and more than 35,000 die from antibiotics.

“If we had the time to cultivate our knowledge and harness the chemical power of plants, that’s it,” says Quave. “There is an increase in antimicrobial resistance around the world. At the same time, plant biodiversity is being significantly lost.”

According to a 2020 report on plants and fungi around the world by the Royal Botanical Gardens of Kew, it is estimated that two of the five plants are now endangered.

Quave is a leader in the field of medical ethnobotany, studying how indigenous peoples incorporate plants into healing practices to discover promising candidates for new drugs.

Quave Labs has identified compounds from plants that inhibit dangerous antibiotic-resistant strains, such as Brazilian pepper trees, American beauty berries, and European chestnuts.

Her lab, for example, found that triterpenoid acid from the Brazilian pepper tree “disarms” methicillin-resistant Staphylococcus aureus, known as MRSA, by blocking its ability to produce toxins.

The first antibiotic, penicillin, was derived from a fungal microbe that kills bacteria. Since then, scientists have discovered other microorganisms that live in soil that are easy to grow in a laboratory setting and can kill pathogens that are resistant to some drugs.

However, the ability of bacteria to continue to evolve resistance outweighs the ability to produce effective drugs from these sources.

“One of the obstacles to incorporating natural products into the new drug pipeline is the complexity of the discovery process,” says Quave.

“We need to identify promising plant candidates, look at hundreds of chemicals in a particular plant to identify active compounds, and isolate these compounds well to perform experiments. Soil microbiology sequencing It’s not easy. I grew a big tub to do the experiment. “

She adds that leveraging the knowledge of traditional people who have used plants to treat infectious diseases for centuries provides valuable clues as to where to focus their research.

“In recent decades, there has been a growing interest in investigating plants as potential drug candidates,” says Quave. “Technology has improved to allow easy access and study of bioactive molecules in plants, and more papers have been published that follow standardized procedures for assessing antibacterial activity between plant compounds.”

In the current review, Quave Labs examined approximately 200 papers published between 2012 and 2019 that met strict standardization criteria for certifying plant-derived compounds that significantly inhibit antibacterial activity. It was.

The co-authors spanned undergraduates who conducted the first literature review of graduate students and scientists specializing in biology, chemistry, pharmacology, and / or botany.

The 459 compounds included in the review cover a wide variety of species, including those from commonly known plant families such as citrus, daisies, beans and mint.

Compounds are classified into three major chemicals. About half are classified as phenol derivatives, about 25% are terpenoids, about 6% are alkaloids, and the rest are other metabolites.

The authors of the review selected 183 compounds and further discussed their antibacterial activity, biosynthesis, chemical structure, mechanism of action, and potential as antibiotics.

“These are all naturally occurring compounds, not synthesized or derivatized by chemists,” explains Quave. “We wanted to bring promising drug candidates to the forefront and provide a systematic overview that opens up new chemical spaces for discovery.

Our review serves as a starting point for chemists to consider whether any of these compounds could be optimized and become a scaffold for antibiotic treatment. “