While a range of drugs are used to ameliorate the effects of type 2 diabetes and its complications, they tend to slow rather than stop the progression of the disease (1). Many herbs have been used traditionally by different cultures in the management of type 2 diabetes (2); however, in general there is little scientific evidence to support their efficacy. The aim of this project was to conduct a small-scale trial to examine the effects of a commercial combination of Trichosanthes kirilowii, Polygonatum sibiricum, Dioscorea oppostia, Panax ginseng, and Stevia rebaudiona and chromium nicotinamide (Glucostat; Health World Limited, Eagle Farm, Australia) on type 2 diabetic subjects who are not yet taking orthodox medication.
Four male and six female subjects aged between 33 and 70 years who had been diagnosed with type 2 diabetes and were on a low glycemic diet participated in this study. They were administered a 3.2-g dose three times a day over a 90-day period. Fasting blood glucose (FBG) data were collected daily using handheld glucometers, and HbA1c (A1C), cholesterol, and BMI were recorded at the start and end of the trial. This study was approved by the human ethics committee at the University of New England.
The mean FBG for all patients at the start of the study was 9.4 ± 1.1 mmol/l and ranged from 7.6 to 11.3 mmol/l. Nine patients responded to the treatment showing a significant, though moderate, decrease (10 ± 4%) in FBG; however, while A1C, cholesterol, and BMI also declined, this did not reach significance. When treatment stopped, FBG rose rapidly over 15–20 days to pretreatment concentrations; however, when treatment was resumed (n = 5) FBG again declined by 14.3% (range 8–21) over the following 6 weeks.
This herbal combination may have some benefit in the treatment of type 2 diabetes, particularly perhaps in the early stages of the disease. The effects, while significant, took time to become apparent, and the herbal combination appears to slowly improve the FBG concentrations over a period of continuous use. Surprisingly, this effect was rapidly reversed when the treatment ceased, as blood glucose retuned to pretreatment levels within 15–20 days. Those subjects who started to take the herbal remedy again after the withdrawal period showed a more rapid decline in their FBG concentrations than when they first started the treatment. It is unclear from this study whether the FBG would return to euglycemia over a longer period of time, but it appears that the rate of decline slows and may plateau before this was reached.
This study strongly suggests that this combination of traditional Chinese herbs, together with chromium, may be effective in improving glycemic control in people diagnosed with type 2 diabetes. The mechanism of action remains unclear and may be a combination of an increase in insulin responsiveness and glucose uptake. The relative importance of the individual component herbs is also unknown, and we are undertaking further studies to investigate this.