Determination of Total Chlorogenic Acids in Commercial Green Coffee Extracts

Obesity and type II diabetes are serious health problems and are among the leading causes of death. There are a few prescription weight loss drugs, but they have a high cost and their adverse effects have limited their widespread use. For the consumer, the use of dietary supplements represents a natural and presumably safer means of losing weight. A high-pressure liquid chromatography (HPLC) method was developed to provide a simple, inexpensive method for analysis of 54 commercially available extracts of green coffee beans. Both chlorogenic acids (CGAs), which are the purported bioactives, and caffeine were measured using 5-chloroquinic acid as the standard and published extinction coefficients for the other monomeric and dimeric CGAs present. The average labeled dose of CGA was 233 mg, whereas the average calculated by HPLC analysis was only 157 mg. Thus, the consumer is likely to obtain product containing a little more than half of the reported label amount of CGA. Caffeine levels ranged from 0% to 17%. The marketing literature touts 50% CGA content as being the gold standard of green coffee bean extract products. Based on this value, only 28% of the commercial products we studied met this goal.