The purpose of this study was to evaluate the effect of mixed extracts of aralia cortex and phellodendron cortex (P55A) on activities of human gingival fibroblasts and periodontal ligament cells in vitro.

First experiment was done to evaluate the effect of PS5A in normal condition. In control group, die cells(4.5 × 10⁴cells/ml) were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum. In experimental groups, P55A was added to the above culture condition at the final concentrations of 0.1 µg/ml(Test group 1),1 µg/ml(Test group 2) and 10 µg/ml(Test group3). Then each group was tested for the cell proliferation rate at ½, 2, 5 days, protein levels at 2, 5 days, and alkaine phosphatase activity at 2, 5 days.

Second experiment was done to evaluate the effect of P55A in high glucose condition. 200 mg/dl glucose was added to the same culture condition of all groups in first experiment. Then each group was tested for the cell proliferation rate at ½, 2, 5 days, protein levels at 2, 5 days, and alkaline phoaphatase activity at 2, 5 days.

The results were as follows;

1. First experiment

1) As P55A concentration increased, cell proliferation rate increased significantly in test group 2 at 2 days, and test group 2 and 3 at 5 days in human gingival fibroblasts and periodontal ligament cells( P <0.05).

2) In human gingival fibroblasts, all test groups showed significantly increased protein levels as compared to control group at 5 days. In periodontal ligament cells, test group 2 and 3 showed significantly increased protein levels as compared to control group at 2, 5 days( P <0.05).

3) Alkaline phosphatase activity of human periodontal ligament cells increased as P55A concentration increased. The test group 2 and 3showed significant increase as compared to control group at 5 days( P <0.05).

2. Second experiment

1) As P55A concentration increased, cell proliferation rate increased significantly in test group 2 at 2 days, and test group 2 and 3 at 5 days in human gingival fibroblasts and periodontal ligament cells( P <0.05).

2) In human gingival fibroblasts, all test group 3 showed significantly increased protein levels as compared to control group at 2 days, and all test groups at 5 days. In periodontal ligament cells, test group 2 and 3 showed significantly increased protein levels as compared to control group at 2, 5 days( P <0.05).

3) Alkaline phosphatase activity of human periodontal ligament cells increased as P55A concentration increased. The test group 2 and 3 showed significant increase as compared to control group 2 at 2 days, and all test groups at 5 days( P <0.05).

From the above results, mixed extracts of aralia cortex and phellodendron cortex appeared to enhance cellular activities including cell proliferation rate, protein levels and alkaline phosphatase activity of human gingival fibroblasts and periodontal ligament cells in normal and high glucose condition. This study suggests that mixed extracts of aralia cortex and phellodendron cortex seem to be able to subside the inflammation of periodontal tissue and regenerate the destructed periodontal tissue.