Plant fights mouth bacteria
The study found that emu bush could
be a viable alternative - instead of killing
bacteria, it prevents them from producing
acid, which may avoid some side effects.
Image: iStockphoto

In the fight against tooth decay, an Australian native plant’s antibacterial properties could provide a natural alternative to medicated mouthwashes.

Research conducted at Swinburne University’s Environment and Biotechnology Centre has found that extracts from the emu bush (Eremophila longifolia) can inhibit the growth of oral bacteria, reduce dental plaque development and stop bacteria from sticking to tooth surfaces.

Emu bush has been used in traditional Indigenous medicine for many thousands of years, but may now find its way into more modern products like toothpaste or mouthwash.

Swinburne student Elisa Hayhoe investigated the plant’s antibacterial potential for her biotechnology Honours project.

“Although oral bacteria may sound fairly benign, the tooth decay and loss it causes affects quality of life and has links to chronic conditions and systemic diseases,” Hayhoe said.

“For example, several species of bacteria that cause periodontal disease – where tissue and bone supporting the teeth erode – have been found in the plaque clogging up arteries in the heart.

“When these bacteria are exposed to sugar they produce acid, which starts to dissolve teeth. Yet like bacteria in the gut, there are ‘good’ and ‘bad’ oral bacteria.”

Hayhoe set out to explore if emu bush could be used not to kill oral bacteria, but prevent these micro-organisms from producing acid.

In conjunction with pharmaceutical research company Canopus Bio Pharma, she tested various concentrates of emu bush extract in isolation and in the presence of saliva. Hayhoe found that this native plant could stop the two major bacteria involved in tooth decay - Streptococcus mutans and Streptococcus sobrinus - from producing acid.

It could also prevent bacteria from sticking to teeth to create plaque and cut through existing plaque to prevent further build up.

“It works as well as commercial and medicated mouthwashes at removing bacteria,” Hayhoe said.

Associate Professor Enzo Palombo said Swinburne’s Environment and Biotechnology Centre had a decade-long program investigating traditional, Aboriginal medicines, and the plants associated with them.

“These medicines have been used for centuries, so we start out by thinking that they are most likely safe and they must have some activity against bacteria or micro-organisms.

“An alternative anti-bacterial agent against tooth decay could reduce the side effects of existing medicines, such as vomiting and tooth staining, and provide a cost-effective option for developing countries.”

Palombo said emu bush, which is found across inland Australia, could also have other medical uses as an anti-microbial coating agent for plastics used in hospital procedures.

Editor's Note: Original news release can be found here.