Effect of Origanum dubium, Origanum vulgare subsp hirtum, and Lavandula angustifolia essential oils on immune cells in athletes

Natural herbal products are widely used by athletes to reduce the immune suppression caused by intensive exercise. This study aimed to determine the effects of the essential oils Origanum dubium, Origanum vulgare subsp hirtum, and Lavandula angustifolia, which belong to the Lamiaceae family, on immune cells in athletes. Thirty-four trained men (age: 19.8 +/- 1.7 years, height: 177 +/- 4.3 cm, body mass: 69.3 +/- 7.6 kg) were randomly assigned to one of three experimental groups or the control group. Leukocytes and their subgroups were measured before and after a 14-day essential oil intervention and following an intensive exercise session. The main findings indicated that es-sential oils isolated from O. dubium (F2 : 66 = 10.1; p = 0.011; eta 2p = 0.58; 29.9% increase), O. vulgare subsp hirtum (F2 : 66 = 15.6; p < 0.001; eta 2p = 0.66; 25.4% increase), and L. angustifolia (F2 : 66 = 29.7; p < 0.001; eta 2p = 0.79; 19.9% increase) increased lymphocyte counts, thus maintaining baseline levels despite decreased post-exercise lymphocyte counts. Additionally, the post-exercise lym-phocyte count was lower than that after the intervention (2.71 +/- 0.51 vs. 2.96 +/- 0.68; p = 0.046) but higher than at baseline (2.71 +/- 0.51 vs. 2.36 +/- 0.58; p = 0.015) in the O. vulgare subsp hirtum group. The lower post-exercise lymphocyte counts of the control group compared with those after the 14-day period (1.97 +/- 0.49 vs. 2.37 +/- 0.38; p < 0.001) and baseline (1.97 +/- 0.49 vs. 2.38 +/- 0.52; p = 0.005) supported the experimental group results. However, our findings revealed that es-sential oil interventions had no significant effect on neutrophil counts, but the intensive exercise intervention increased the neutrophil counts in all groups. No significant change was identified in the other subgroup counts following the essential oil intervention or post exercise. Therefore, the results of this study indicate that these plants, especially O. vulgare subsp hirtum, can be used to alleviate the immune suppressive effects of intense exercise in athletes.