Macrophage Activity and Capacity Following Oral Administration of Cocoa Extract to Mice

The activity of an ethanolic extract from cocoa bean (Theobroma cacao L.,) towards the non-specific immune response in mice being challenged with Staphylococcus epidermidis was studied. Mice (Swiss-Webster, 12 weeks old, 35 ± 1.9 g) received oral administration of cocoa extract (CE), positive control or negative control, every day for seven consecutive days. Cocoa extract (CE) was in three different doses, i.e. CE1 7.14 mg/30 g body weight (BW), CE2 14.28 mg/30 g BW, and CE3 28.57 mg/30 g BW. The positive control was Phyllanthus niruri Linn. (PN) extract (Stimuno®) 17.55 mg/30 g BW, while the negative control was sterile water (SW). On day 8, mice were given intraperitoneal injections of S. epidermidis suspension (0.5 ml, 105 CFU). After being settled for one hour, mice were sacrificed and peritoneal fluid was withdrawn for staining and microscopy observation. The number of macrophages performing phagocytosis and number of bacterial cells being recruited were counted. CE increased the number of active macrophages as well as enhanced macrophage phagocytic capacity against S. epidermidis cells. Various doses of CE increased the number of active macrophages from 46 ± 5% (SW) to 73 ± 3% (CE1), 76 ± 3% (CE2), and 85 ± 12% (CE3). Phagocytic capacity was elevated more than 2-fold after consumption of CE, from 215 ± 25 cells (SW) to 437 ± 9 cells (CE1), 452 ± 4 cells (CE2), and 511 ± 6 cells (CE3). CE3 with the highest dose had activity equal to that of PN (p = 0.68; α = 0.05). This research suggests a potential use of CE as an immunostimulant. This study indicates macrophage activity and capacity in mice were enhanced by oral consumption of cocoa extract.