Effect Of Ursolic Acid Consumption From Apple Wax On Cytokine Levels In The Blood And Handgrip Strength

The wax of apples contains ursolic acid, a triterpenoid that has been shown to have anti-inflammatory properties and increase muscle hypertrophy. Study participants consumed either a whole apple, peeled apple, or no apple, each weekday for three weeks in order to determine the effect of ursolic acid on pro- and anti-inflammatory cytokine levels in the blood and handgrip strength. Blood samples and handgrip strength measurements were taken from the participants (N=32, age = 52±8, BMI = 31.2±5.5) at the beginning and end of the three-week intervention. The blood samples were analyzed for cytokines using a bead-based multiplex assay. Dominant handgrip strength decreased significantly in all three groups over time (35.283 kg pre-intervention, 33.753 kg post-intervention; p = 0.015). IL-8 levels decreased significantly post-intervention in the Whole Apple group (150.250 vs. 113.833 pg/mL; p=0.034), and tended to decrease in the Peeled Apple (162.364 vs. 129.564 pg/mL; p=0.078) and No Apple (156.778 vs. 122.556 pg/mL; p=0.081) groups. There were no significant changes in IL-1ß, IL-6, IL-10, or TNF-a post-intervention. Aside from IL-8, no significant changes could be attributed to ursolic acid consumption. IL-8 levels tended to decrease in all groups, so the decrease may not be due to ursolic acid consumption.