Correlation of increased antioxidation with the phenolic compound and amino acids contents of Camellia sinensis leaf extracts following ultra high pressure extraction

Antioxidants are indispensable for protecting skin cell membranes against oxidative injury caused by reactive oxygen species and other free radicals. Likewise, phenolic compounds are also important barriers to such oxidative injury. In this study, we examined the correlation between increased antioxidation and the contents of phenolic compounds and amino acids in Camellia sinensis leaf extracts obtained by ultra-high pressure extraction. Compared with extracts obtained by leaching and ultrasonic extraction, to evaluate whether this method can improve the pharmacologic effects of C. sinensis leaves. The ultra-high pressure (50 and 100 MPa) extracts had tremendous enhancement of their extraction yield, 1,1-diphenyl-2-picrylhydrazyl (free radical)-scavenging activity and superoxide anion radical scavenging activity, as well as the total phenolic, amino acid, and caffeine contents. The antioxidative effects were promoted not only by the phenolic compounds contents but also by other factors such as the amino acids content in the C. sinensis leaf extracts. These effects showed pressure-dependent increase with the enhanced phenolic compound and amino acid contents of the ultra high pressure extracts. Taken together, ultra high pressure extraction is a potentially useful method for the pharmaceutical, cosmetic, and food industries, because it improves the antioxidative effects of C. sinensis leaves.