Aldehydes or ketones can react with amino compounds to form Schiff base adducts, which have been widely studied and shown to exhibit antimicrobial, antioxidant or antiviral activity. Salicylaldehyde (SA) and cinnamaldehyde (CA) are components of plant essential oils. γ-Aminobutyric acid (GA) is an important substance in the mammalian central nervous system and responsible for many bioactivities. This study aimed to synthesize functional Schiff base adducts using GA and SA or CA; to study the antimicrobial activity, antioxidant activity and tyrosinase-inhibition activity of these adducts (SA-GA and CA-GA) and their metal complexes--SA-GA-Cu (or Zn) and CA-GA-Cu (or Zn); and to find their applications in food systems. SA-GA and CA-GA both exhibited good antibacterial effects, and so did their Cu complexes. As for antioxidant activity, SA-GA and CA-GA were superior to their metal complexes in most tests. Regarding inhibition of enzymatic browning of mushrooms, both SA-GA-Cu and CA-GA-Cu could inhibit tyrosinase activity effectively.
Keywords: Antimicrobial activity; Antioxidant activity; Cinnamaldehyde; Mushroom browning; Salicylaldehyde; Schiff base; Tyrosinase; γ-Aminobutyric acid.
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