Efficacy of Bofu-tsusho-san, an oriental herbal medicine, in obese Japanese women with impaired glucose tolerance

1. In the present study, we conducted the first randomized, double-blind, placebo-controlled study of bofu-tsusho-san (BF), an oriental herbal medicine (24 mg/day ephedrine in Ephedrae Herba and an efficacy equivalent of 280 mg caffeine, judging from the phosphodiesterase-inhibitory effect of Glycyrrhizae Radix, Forsythiae Fructus and Schizonepetae Spica and another 14 crude drugs) in obese women with impaired glucose tolerance (IGT). 2. The aim of the present study was to determine whether BF was effective in decreasing visceral adiposity and insulin resistance. Eighty-one Japanese women (body mass index (BMI) 36.5 +/- 4.8 kg/m(2)) with IGT and insulin resistance (IR), who had been treated with a low-calorie diet (5016 kj/day: 1200 kcal) and an exercise regimen (1254 kj/day: 300 kcal), were randomized to receive either placebo (n = 40) or BIT treatment (n = 41) three times a day. 3. After 24 weeks treatment, the BF group lost significantly (P < 0.01) more bodyweight and abdominal visceral fat without a decrease in the adjusted resting metabolic rate (RMR), whereas the placebo group lost bodyweight (P < 0.05) and had no significant change in abdominal visceral fat. The BF group had a lower fasting serum insulin level (P < 0.05), a lower insulin area under the curve (P < 0.05) and a lower level of the homeostasis model assessment of insulin resistance (P < 0.01) compared with values before treatment. 4. We conclude that BF could be a useful herbal medicine in treating obesity with IGT.