If the research, by scientists from the East China Normal University, can be reproduced in humans, then feeding on a pumpkin extract may promotes regeneration of damaged pancreatic cells in diabetic rats, boosting levels of insulin-producing beta cells and insulin in the blood.
"The present study provides substantial evidence to demonstrate the hypoglycaemic action of C. ficifolia fruit extract as well as its role as antioxidant agent and thus reveals a mechanism for its cytoprotective action," wrote authors Tao Xia and Qin Wang in the Journal of the Science of Food and Agriculture .
"Perhaps this is the first report showing the antioxidant role of C. ficifolia fruit extract and suggesting its utility in the control of diabetes," added the authors.
The rats used in this study modelled type-1 diabetes, but the researchers believe the pumpkin extract may also play a role in type-2 diabetes.
Type-1 diabetes occurs when people are not able to produce any insulin after the cells in the pancreas have been damaged, thought to be an autoimmune response.
An estimated 19 million people are affected by type-2 diabetes in the EU 25, equal to four per cent of the total population.
This figure is projected to increase to 26 million by 2030.
In the US, there are over 20 million people with type-2 diabetes, equal to seven per cent of the population.
The total costs are thought to be as much as $132 billion, with $92 billion being direct costs from medication, according to 2002 American Diabetes Association figures.
Tao Xia and Qin Wang divided 12 diabetic rats and 12 normal rats into two groups, one fed a normal diet and the other fed the normal diet supplemented with the pumpkin extract for 30 days.
The extracts were prepared in-house using methanol.
At the end of the study, the researchers report that diabetic rats fed the extract had only five per cent less plasma insulin and eight percent fewer insulin-positive (beta) cells compared to normal healthy rats.
"Pumpkin extract is potentially a very good product for pre-diabetic persons, as well as those who have already developed diabetes," lead author Tao Xia from told Chemistry & Industry magazine.
The mechanism behind the potential benefits was proposed to be due to both antioxidants and D-chiro-inositol, a molecule that mediates insulin activity.
Boosting insulin levels has the effect of lowering blood sugar levels, which reduces levels of oxidative oxygen species that damage beta-cell membranes, preventing further damage and allowing for some regeneration.
The researchers note however, that beta cells levels in the diabetic rats are unlikely ever to reach that of controls, because some of the cells will have been damaged beyond repair.
"Thus our studies support the notion that supplementation of C. ficifolia fruit extract to diabetic patients would help in achieving good glycaemic and metabolic control and prevent long-term complications as a result of the protection offered by its antioxidant action; probably preserving the residual ß-cell mass without further loss," they concluded.
Commenting independently on the research, David Bender from Royal Free and University College Medical School, London, told Chemistry & Industry magazine that the research was very exciting.
"The main finding is that feeding pumpkin extract prevents the progressive destruction of pancreatic betacells," he said.
Bender added a note of caution however and said that is was too early to promote pumpkin as a prevention or treatment for diabetes.
Large-scale human trials are needed and until then it is impossible to know whether pumpkin extract could have the same effects in humans.
Sources: Journal of the Science of Food and Agriculture Volume 87, Issue 9, Pages 1753-1757 "Hypoglycaemic role of Cucurbita ficifolia (Cucurbitaceae) fruit extract in streptozotocin-induced diabetic rats" Authors: Tao Xia and Qin Wang Chemistry & Industry 9 July 2007, Page 9 "Eating pumpkins helps diabetics" Author: L. Richards