Objective: Flavonoids from preparation Comfort-G have, beside of antioxidant effects, the anti-inflammatory effect, too. Comfort-G inhibits both COX-1 (cyclooxygenase-1)/COX-2 (cyclooxygenase-2) and 5-LO (5-lipoxygenase) enzymatic activity thereby decreasing the transformation of arachidonic acid (AA) to prostaglandins, thromboxanes, and leukotrienes. Our goal was to confirm this finding by the analysis of the content of AA in synovial fluid and serum of patients suffering by synovialitis of knee joint. Design: Interventional study. Settings: IV Department of Internal Medicine, Charles University in Prague, First Faculty of Medicine and General Teaching Hospital in Prague. Material and Methods: Comfort-G was given to the group of ten patients (4M/6F) aged 27–79 years in prescribed dose (equal to 250 mg of flavonoid extract twice a day) for one month. Synovial fluid and serum were drawn before first application of the preparation (day 0) and one day after the last application (day 31). Free radicals (FR) were determined by direct spectrophotometric method based on chlorophyllin reaction with FR; composition of fatty acids, including arachidonic acid, was measured by gas chromatography. The probands were also asked to respond to a questionnaire (subjective evaluation) and they were also examined by the physician. Following changes of knee joint were evaluated: swelling and degree of motion-angle. Statistical analysis was performed with the help of software STATISTICA for Windows, version 4.0. Results: The results showing the statistically significant decrease of free radical concentration in both synovial fluid and serum were presented and discussed in previously presented paper as well as the observed amelioration of patient stage. After the trial period, we found increased content of AA in both synovial fluid (4.54 ± 0.39 vs. 6.73 ± 0.82 mol%, p = 0.005) and serum (4.78 ± 0.90 vs. 6.57 ± 0.98 mol%, p = 0.01) in the same group of patients. Conclusion: Our results confirm that flavonoids from Comfort-G are able to decrease the amount of FR and increase the concentration of AA especially in synovial fluid, but also in serum of patients. This finding corresponds with the suggestion that the enzymatic transformations of AA resulting in production of pro-inflammatory compounds are blocked. The next consequences concerning other parts of organism and impact of our results in case of other diseases are discussed.

        Key words: Comfort-G, arachidonic acid, COX-2, 5-LO, inflammation