This study analyzed the composition and contents of acacia flower extracts, free amino acid of methanol extracts and polyphenol compound. Then, the physiological activities of some cosmetics were examined. The study results found the followings:

1. The free amino acid of acacia flower extracts was 36.96 mg/g in total, and a total 16 types of free amino acids were isolated. Among them, Alanine was the highest with 5.04 mg/g.

2. Even though it is not a protein, the amino acid compounds which exist in a free state were 6.54 mg/g in 9 types in water extract. Among them, R-aminobutyric accounted for the greatest portion with 4.26 mg/g. In methanol extract, however, a total of 4.02 mg/g were found in 7 different types. Among them, carnosine accounted for the greatest portion with 1.17 mg/g.

3. In terms of polyphenol contents, methanol extract (127.30 ± 1.72 mg%) was slightly higher than hot-water extract (114.60 ± 2.30 mg%). In terms of flavonoid contents, in addition, methanol extract (91.10 ± 1.13 mg%) was about 1.2 times higher than hot-water extract (75.50 ± 2.10 mg%).

4. Regarding the composition and contents of polyphenol compound, 11 different types of phenolic acids (ex: gallic acid, protocatechuic acid, 4-hydroxybenzoic acid, caffeic acid, isovanillic acid, p-coumaric acid, ferulic acid, t-coumaric acid, rosmarinic acid, etc.) and two types of flavonoids (rutin, taxifolin) were found in hot-water and methanol extracts. In the hot-water extract, isovanillic acid was the highest with 910.70 ㎍/g among the seven phenolic acidic components. Among the flavonoid components, rutin was the highest with 698.60 ㎍/g. In methanol extract, on the contrary, caffeic acid was the highest with 698.60 ㎍/g among six phenolic acidic components. In terms of flavonoid, taxifolin was 6.82 ㎍/g, about 7 times lower than the level in hot-water extract.

5. The DPPH radical scavenging activity was 33.06 ± 0.17%, 38.37 ± 0.85% and 74.09 ± 0.23% at 1 mg/㎖, 2 mg/㎖ and 3 mg/㎖ respectively in the hot-water extract. It increased in proportion to the concentration. In the methanol extract, it was 25.93 ± 0.94%, 40.51 ± 0.5% and 58.46 ± 0.52% at 1 mg/㎖, 2 mg/㎖ and 3 mg/㎖ respectively. Just like the case in the hot-water extract, as the concentration increased, anti-oxidation capacity increased as well.

6. The inhibitory activity of tyrosinase in the hot-water extract of acacia flower was 11.40 ± 0.69%, 12.75 ± 0.52 and 15.20 ± 0.36 mg/㎖ at 1 mg/㎖, 2 mg/㎖ and 3 mg/㎖ respectively. In the methanol extract, it increased in proportion to the concentration as follows: 15.68 ± 0.58%, 17.28 ± 0.3 and 20.58 ± 0.55% at 1 mg/㎖, 2 mg/㎖ and 3 mg/㎖ each. Compared to the inhibitory activity of tyrosinase in the control group-treated arbutin, however, the inhibitory activity of tyrosinase in the hot-water extract of acacia flower and methanol extract was low.

7. The ell growth according to human skin cell line, HaCaT was very low cell growth inhibited in an concentration-dependent.

8. The inhibitory activity of elastase and collagenase in the hot-water extract and methanol extracts increased in a concentration-dependent manner. Compared to the hot-water extract, it was higher in the methanol extract.

The said results show that because free amino acid and polyphenol contents are rich in the hot-water extract of acacia and methanol extract, they could be very useful as cell growth activating factors or natural antioxidants. To use them as cosmetic materials, however, there should be further studies on correlations between the enzyme activity in the cell and various cosmetic components.