Concurrent HPLC detection of javamide-I/-II, caffeine, 3- O-caffeoylquinic acid, 4-O-caffeoylquinic acid and 5-O-caffeoylquinic acid; their comparative quantification and disparity in ground and instant coffees

Authors: Park, Jae

Submitted to: Separation Science Plus
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/18/2019
Publication Date: 5/10/2019
Citation: Park, J.B. 2019. Concurrent HPLC detection of javamide-I/-II, caffeine, 3- O-caffeoylquinic acid, 4-O-caffeoylquinic acid and 5-O-caffeoylquinic acid; their comparative quantification and disparity in ground and instant coffees. Separation Science Plus. 1-7. https://doi.org/10.1002/sscp.201900022.
DOI: https://doi.org/10.1002/sscp.201900022

Interpretive Summary: The accumulating data suggest that the health benefits of coffee consumption on several human diseases such as diabetes and fatty liver disease. Therefore, there is a growing interest for health-orientated coffee products. Instant coffee powder is a coffee product widely used for preparing coffee drinks. In addition to preparing coffee drinks, the coffee powder is also used in savoring baking goods and cooking as a sugar-free coloring/flavoring substitute. Coffee contains several biologically important chemicals such as 3'-CQA (3-O-caffeoylquinic acid), 4'-CQA (4-O-caffeoylquinic acid) and 5'-CQA (5-O-caffeoylquinic acid), and caffeine (2-5). Although they have been considered as main coffee chemicals with several purported health effects, there are still lingering questions about their efficacy. Javamide-I/-II are relatively new bioactive compounds found in several coffee products. Interestingly, javamide-I/-II and their analogues were reported to have several important biological activities including anti-inflammation activity, suggesting that they may play roles in coffee-related health effects. However, the amounts of javamide-I/-II have not been determined in instant coffee samples to date. Therefore, in this paper, a simplified/inclusive reversed-phase high-performance liquid chromatography method was developed to measure concurrently and reproducibly javamide-I/-II, 3'-CQA, 4'-CQA, 5'-CQA and caffeine; and their amounts were quantified in ten instant coffee powders available in the market. Our study showed that the developed HPLC method enabled the simultaneous/reproducible measurement of 3'-CQA, 4'-CQA, 5'-CQA, caffeine and javamide-I/-II, which were present in different amounts in the tested coffee samples and the data also suggest that potential health effects attributed to these chemicals may be different, dependent upon coffee brands.

Technical Abstract: Instant coffee powder is commonly used to make coffee drinks. In fact, instant coffee powder contains a number of biologically important chemicals such as caffeine, 3'-CQA, 4'-CQA, and 5'-CQA. For years, they have been regarded as major antioxidant/anti-inflammatory compounds in coffee. However, recent reports suggested that javamide-I/-II found in coffee products may have anti-inflammatory activity greater than 3'-CQA, 4'-CQA, 5'-CQA and caffeine. Therefore, there is a pressing need to quantify javamide-I/-II in coffee products including instant coffee powder. Therefore, in this paper, an inclusive HPLC method was developed to measure javamide-I/-II with fine separation, resolution and reproducibility. Surprisingly, the developed HPLC method was also able to measure 3'-CQA, 4'-CQA, 5'-CQA and caffeine concurrently with javamide-I/-II. Therefore, using this HPLC method, the amounts of javamide-I/-II were quantified with 3'-CQA, 4'-CQA, 5'-CQA, and caffeine in ten instant coffee powders. In all ten samples, 3'-CQA, 4'-CQA, 5'-CQA, and caffeine were detected; caffeine (24-41 mg/g), and 3'-, 4'-, 5'-CQAs (2.1-14.6 mg/g). However, javamide-II was detected in six instant samples (0.49 -1.75 mg/g) and javamide-I was only detected in five coffee samples (0.21 -0.38 mg/g), suggesting that there is an apparent discrepancy of their amounts in the tested samples. Additionally, the data showed that caffeine was the least variable compound and javamide-I/-II were the most variable compounds (P < 0.05) in the samples. Altogether, the data indicate that the developed HPLC method enabled the simultaneous/reproducible measurement of 3'-CQA, 4'-CQA, 5'-CQA, caffeine and javamide-I/-II which were present in different amounts in the tested samples, and potential health effects accredited to these chemicals may not be equivalent in instant coffee products.