Immunostimulatory properties of bigroot geranium (Geranium macrorrhizum L.) extract

The aim of the study was to investigate the immunostimulatory properties of bigroot geranium.
Material and methods. Possible nonspecific characteristics of bigroot geranium were evaluated by the total leukocyte count in the peripheral blood, and qualitative changes of blood were assessed using Shilling’s formula by evaluating changes in lymphocyte counts. In addition, we also studied changes in the counts of Tcell precursors in the thymus and B lymphocytes in the spleen. Ethanol extract of the leaves of bigroot geranium was produced at the Department of Food Technology, Kaunas University of Technology. Studies were performed on mice Bl 57 (n=21). The control group (n=7) received distilled water at a dose of 1 mL/day. The second and third groups received 1% and 10% extract of bigroot geranium, respectively, as a food supplement. Changes in cell counts were investigated after 4 weeks following the initiation of the trial.
Results. After a 4-week administration of 1% extract of bigroot geranium (1 mL/day) (mice group, n=7), leukocyte count in the peripheral blood increased to 6.1×10⁹ cells/L, and lymphocyte count – to 70%, but changes were not statistically significant. The other case group of mice (n=7) received 10% extract of bigroot geranium for 4 weeks at a dose of 1 mL/day. In this group, leukocyte count in the peripheral blood increased statistically significantly from 4.4×10⁹ cells/L to 7.2×10⁹ cells/L (p<0.01), and lymphocyte percentage – from 52% to 80% (p<0.001), as compared to control. Thymocyte (T lymphocytes) counts in thymus and splenocyte (B lymphocytes) counts in the spleen showed a tendency to increase after the administration of 1% and 10% extracts. After a 4-week administration of 1% extract of bigroot geranium, thymocyte and splenocyte counts increased from 0.342×10⁶ cells to 0.372×10⁶ cells per mg of tissue and from 0.395×10⁶ cells to 0.405×10⁶ cells per mg of tissue, respectively, as compared to control group (p>0.1). After the administration of 10% extract of bigroot geranium, thymocyte count increased to 0.488×106 cells per mg of tissue (p<0.01), and splenocyte count – to 0.504×10⁶ cells per mg of tissue (p<0.01).
Conclusion. The extracts of the leaves of bigroot geranium increased leukocyte count and lymphocyte percentage in the peripheral blood, and after a 4-week administration of 10% extract of bigroot geranium, a statistically significant increase in the counts of T lymphocytes (in the thymus) and B lymphocytes (in the spleen) was observed. The immunostimulatory effect depends on the dose of the extract.