Release of intermediate reactive hydrogen peroxide by macrophage cells activated by natural products

By determining the hydrogen peroxide (H2O2) released in cultures of periton eal macrophage cells from Swiss mice, we evaluated the action of 27 vegetab le compounds (pristimerin, tingenone, jatrophone, palustric acid, lupeol, c ladrastin, ocoteine, boldine, tomatine, yohimbine, reserpine, escopoletin, esculine, plumericin, diosgenin, deoxyschizandrin, p-arbutin, mangiferin, a nd others) using a 2 mg/ml solution of each compound (100 mug/well). Macrop hages are cells responsible for the development of the immunological respon se reaction, liberating more than one hundred compounds into the extracellu lar environment. Among these are the various cytokines and the intermediate compounds of nitrogen (NO) and oxygen (H2O2). This coordinated sequence of biochemical reactions is known as the "oxidative burst." When we compared the results with those obtained with zymosan (an important stimulator of H2 O2) we observed that the compounds showing the highest activity were substa nces 2 (tingenone), 16 (reserpine) and 20. Other substances such as compoun ds 1, 4, 5, 6, 8, 12, 13, 14, 15, 17, 19, 23, 24, 26, and 27 also showed a certain activity, but with less intensity than the aforementioned ones. Com pounds 3, 7, 9, 10, 11, 18, 21, 22 and 25 presented no activity. These resu lts suggest that natural products (mainly tingenone and reserpine and other s) with different chemical structures are strong immunological modulators. However, further tests are needed to determine the 'oxidative burst' in fut ure studies.