The studies - presented by a team of researchers from King's College, London - confirmed the benefits of common traditional remedies and offered scientific justification for their use.
The researchers concentrated on three sets of plants, namely those used in Indian for the treatment of diabetes, Ghanaian wound healing agents and cancer treatments used in the Far East. They commented that the findings "will help local people identify which plants to recommend and may lead to potential new compounds for pharmaceutical use."
Curry-leaf tree and diabetes
The first herbal to be examined was the curry-leaf tree (Murraya koenigii) from India, which is reputed to help diabetes. Researcher Katie Bawden-Tucknott and colleagues said that their investigations had clearly shown that the plant had potential antidiabetic activity.
They came to this conclusion after developing a test for antidiabetic activity based on the inhibition of a digestive enzyme (pancreatic alpha-amylase), which is involved in the breakdown of dietary starch to glucose.
A patient with diabetes does not produce enough insulin to cope with rapid rises in blood glucose levels. Slowing the rate of starch breakdown, by blocking alpha-amylase, can lead to a more even trickle of glucose into the bloodstream from the intestine.
Professor Peter Houghton, head of the King's College research team, described this as "like restricting people coming out of a station gate in the rush hour so that they come out one at a time rather than seven at a time."
Curry-leaf tree extracts were able to significantly inhibit the enzyme and the researchers are now working to identify the specific active compounds, which are responsible for this action.
When the active component has been isolated and characterized, the scientists believe it should be possible to evaluate whether the agent is likely to have advantages - in terms of efficacy or side effects - over currently marketed antidiabetic drugs that interfere with starch digestion.
Climbing dayflower to heal wounds
The second project was a joint work between King's College and Kwame Nkrumah University of Science and Technology, Ghana, looking at the properties of some plants used by one of the largest ethnic groups in Ghana, the Ashantis, to heal wounds.
At the conference, they presented the results of their experiments using climbing dayflower (Commelina diffusa), which they found had antibacterial and antifungal properties.
"This indicated that the plant is useful in helping wounds to heal and stopping them getting infected," said Houghton.
Thai and Chinese plants in cancer treatment
Asia was the team's next stop. They concluded that plants used in traditional medicine in Thailand and China for the treatment of cancer do appear to have anticancer activities.
The scientists extracted plant materials from both countries using traditional methods, before assessing their in vitro activity in inhibiting growth of cancer cells (a measure of potential therapeutic use) and normal cells (a measure of potential toxicity) through the sulforhodamine B test.
Both sets of plants showed some promising activity against lung cancer cells. The star performer from Thailand was the aquatic weed, Ammannia baccifera, whose active compounds researchers are now attempting to isolate and purify, while the most promising of the Chinese products was the plant Illicium verum, more commonly known as star anise, often found in spice mixtures and cooking pastes, herbal tea blends, and therapeutic and natural health products.
The BPC 2004 is being held at Manchester International Convention Centre, UK between 27 and 29 September.