Identifier

etd-10202009-094300

Degree

Master of Science (MS)

Department

Renewable Natural Resources

Document Type

Thesis

Abstract

The aqueous leaf extract of Rubus suavissimus (Chinese sweet leaf tea) was active in inhibiting angiogenesis, which could be used to suppress adipogenesis and cause weight loss. Following this revelation and approach, the anti-obesity effect was thoroughly investigated in normal and obese rat models. The investigations began with the preparation of quality-controlled extract. First, the crude extraction methods were examined leading to the characterization of the chemical composition. Second, the impure components were removed by alcohol precipitation and column chromatography, resulting in a standardized sweet leaf tea extract (RUS). Third, three bioavailable compounds identified from the urine analyses were re-constituted to form the purified sweet leaf tea extract (GER), which accounted for 27% by weight of the RUS. These standardized and purified sweet leaf tea extracts were then evaluated for their anti-obesity effect in normal and obese-prone rats. Both RUS and GER reduced body weight gain by 7% (p =0.999) in normal rodents but statistical analyses failed to show any significance due to small sample size. Amazingly, it was discovered that the use of the tri-compounds combination (GER) produced the same anti-obesity effect as the standardized extract (RUS). Consequently, new experiments were focused on the GER using obese-prone rats as the study model. GER showed a significant anti-obesity effect by reducing 22% (p¡Ü 0.001) weight gain compared to the high-fat diet control group. Total abdominal fat was reduced significantly by 48%, indicating that the lost body mass was mainly due to the loss of body fat. Other benefits of the Chinese sweet leaf tea extract included lowered blood glucose, cholesterol, and triglycerides. Food intake was not affected. No adverse effects were observed. This research provides exciting insights about the novel use of the Chinese sweet leaf tea as a safe and effective anti-obesity agent beyond its historic use as a natural sweetener. Human clinical investigations are strongly warranted to determine the effective doses and long-term use safety in combating obesity or managing body weight.

Date

2009

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Liu, Zhijun

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