Quick Dips

Plant Antibiotics

Folk medicine often makes use of local plants, and plant physiologists and chemists are discovering active ingredients in many plants that back up the claims of tohunga and shamans.

Researchers at Canterbury University's Plant and Microbial Sciences Department have spent the last ten years examining a range of native plants for anti-fungal, anti-viral and anti-bacterial agents. Their results look promising. Leaves from a variety of plants were freeze-dried and subjected to a battery of purification techniques to isolate biologically active compounds.

The leaves of the Horopito, or Pepper Tree, contain an agent active against the yeast infection Candida albicans, responsible for thrush and skin lesions. The common aralia Patete, or seven finger, was used by the Maori for treating skin disorders. They were utilising the substance falcarindiol, which disrupts the internal organisation of fungal cells. The New Zealand passionfruit has a substance which can inhibit the growth of Pseudomonas bacteria that are resistant to common antibiotics.

"The potential for finding new drugs from plants is enormous when one considers that there must be a quarter to a half million plant species on this planet, yet less than 25% of these have been investigated for pharmaceutical activity," says Dr John Walker.

His team has just begun the second phase of the project, looking for substances that will inhibit the enzymes that diseases need to survive and spread. It's an expensive, time-consuming process and Walker is constantly hunting funding and personnel. Isolating and purifying 100 milligrams of a new substance can take 18 months and cost tens of thousands of dollars.