Chinese herbal formula reduces progression to diabetes by 32%

A combination of 10 Chinese medicinal herbs in a capsule, known as Tianqi, reduced progression to type 2 diabetes in people with impaired glucose tolerance (IGT) in a randomized controlled trial in China.

This is the first study to show that a Chinese herbal medicine can "reduce the progression of prediabetes to diabetes," says study author Chun-Su Yuan, MD, PhD, from the Tang Center for Herbal Medicine Research at the University of Chicago, Illinois. Tianqi "could provide a new option for diabetes management, using herbal medicine alone or as an adjuvant to currently used therapies," he noted.

The results are published online January 16 in the Journal of Clinical Endocrinology & Metabolism, and Dr. Yuan said robust data such as these are needed to help promote the use of Chinese herbal medicine by physicians in different countries.

Most significantly, the researchers found that taking Tianqi reduced the risk for diabetes by almost a third (32.1%) compared with placebo, after adjustment for age and gender.

A Role for Chinese Medicine in Diabetes Prevention?
The findings show that the Chinese herbal medicine was comparable to some pharmaceuticals in reducing progression to type 2 diabetes, say the researchers. For example, the results seen with Tianqi were similar to those found with acarbose, at 25%, and metformin, at 31%.

"Although no direct comparison has been made between Tianqi and antidiabetic prescription drugs, our data indicate that this Chinese herbal medicine had similar effects to metformin," reported Dr. Yuan.

Asked to comment on whether diabetes prevention was regularly practiced in the United States, he remarked that unacceptable adverse effects limited regular use of conventional therapies in the prevention of type 2 diabetes, with reports showing that long-term administration of acarbose or metformin had often been associated with unfavorable gastrointestinal events.

Around 79 million individuals in the United States aged over 20 years have prediabetes, a state in which blood glucose levels are higher than normal but do not meet the diagnostic criteria for type 2 diabetes.

Dr. Yuan added that their data also show that after a period of cessation of the Tianqi treatment, the preventive effects on type 2 diabetes development remained significant. "Moreover, the safety profile of this herbal medicine is very good without obvious adverse effects," he commented.

Chinese Herb Combination and Study Design
The Chinese medicine comprises several herbs that have been shown to lower blood glucose levels after meals. The Tianqi capsule is manufactured by Heilongjiang Baoquan Pharmaceutical and consists of 10 Chinese herbal medicines: Astragali Radix, Coptidis Rhizoma, Trichosanthis Radix, Ligustri Lucidi Fructus, Dendrobii Caulis, Ginseng Radix, Lycii Cortex, Ecliptae Herba, Galla Chinensis, and Corni Fructus. The quality of these herbs and decoction preparation was in accordance with the Chinese Pharmacopoeia, the researchers note.

Dr. Yuan said the key herb in the combination was Huanglian (Coptidis Rhizoma). "The critical component of this herb is berberine, which has been reported to have good antidiabetic effects," he said in an interview. "Huanglian has been used traditionally in Chinese medicine in treating diabetic symptoms."

A total of 420 participants with IGT recruited from 11 research sites in China underwent double-blind randomization to receive either Tianqi (n=210) or a placebo (n=210) for 12 months. Participants had IGT with a 2-hour plasma glucose concentration of 7.8–11.1 mmol/L after a 75-g oral glucose tolerance test and fasting plasma glucose greater than 7.0 mmol/L.

Oral glucose tolerance tests were conducted every 3 months to assess the development of diabetes or restoration to normal glucose tolerance. In addition, all participants received similar lifestyle education.

The primary end point was the conversion of IGT to type 2 diabetes; body weight, body mass index, and adverse effects were monitored.

Need For More Controlled Trials of Chinese Medicinal Herbs
"Although the results of the present study need to be confirmed in future larger clinical trials, Tianqi holds promising potential as an effective and practical means to prevent type 2 diabetes, particularly in places in which herbal medicines are culturally accepted and widely used," say the authors.

They note that treating diabetes with Chinese herbal medicines is popular in China, particularly in rural areas.

"Our encouraging data should initiate further studies, both in China and in the West, to evaluate the role of Chinese herbal medicine in preventing and treating diabetes," said Dr. Yuan. "We are currently conducting several studies in this field."