Anti-tyrosinase kinetics and antibacterial process of caffeic acid N-nonyl ester in Chinese Olive (Canarium album) postharvest.

Enzymatic browning and bacterial putrefaction are mainly responsible for quality losses of Chinese Olive ( Canarium album ) postharvest and lead to very short shelf life on average. Screening anti-browning and anti-bacterial agents is important for preservation of Chinese Olive. Caffeic acid N -nonyl ester (C-9) and caffeic acid N - Heptyl ester (C-7) was synthesized as inhibitors of tyrosinase, which is a key enzyme in browning process. The compound of C-9 could inhibit the activity of tyrosinase strongly and its IC 50 value was determined to be 37.5 μM, while the compound of C-7 had no inhibitory ability. Kinetic analyses showed that compound of C-9 has been a reversible inhibitory mechanism below 50 μM and been irreversible mechanisms above 50 μM. For the reversible inhibitory mechanism, the values of inhibitory constants ( K I and K IS ) were determined to be 24.6 and 37.4 μM, respectively. The results of Chinese Olive fruit postharvest showed that the compound of C-9 could effectively anti-browning and anti-bacterial putrefaction. In addition, this compound had strong antibacterial activities against Staphylococcus aureus , Escherichia coli , Bacillus subtilis and Salmonella . Therefore, C-9 could be a potential anti-browning and anti-bacterial reagent. [ABSTRACT FROM AUTHOR]