Objective: The overproduction of reactive oxygen species leads to oxidative stress, which is related to lifestyle-related disease and cancer. Although antioxidants are considered as one of the countermeasures to oxidative stress, it is necessary to develop the assessment methodology for the antioxidant capacity which is closer to the inner body conditions. In this study, we examined antioxidant actions of plant extracts by using newly-developed neutrophil activity measurement system.
Method: Lemon verbena, Green tea, Camellia japonica and Antiallerge^® were used as plant extracts, and were diluted to medium in wide-range concentrations. Each solution was added on modified Mebiol Gel^® (hydrogel), and the mixture of blood and luminol were set onto the hydrogel in each tube. The amount of reactive oxygen species were measured by luminol-dependent chemiluminescence, whereas the cell count in the hydrogel was quantified as migratory activity of neutrophils.
Result: Lemon verbena and Green tea significantly inhibited reactive oxygen species in a concentration-dependent manner, whereas Camellia japonica and Antiallerge^® did not. The migratory activity of neutrophils was not affected by those plant extracts. Also, damaged cells were not detected.
Conclusion: It was suggested that Lemon verbena and Green tea scavenged reactive oxygen species without causing cell death of neutrophils. This new method for measuring neutrophil activities can be applied not only for assessing the status of inflammation and oxidative stress but also as the screening system for predicting the effectiveness of antioxidant and anti-inflammatory substances.