Ethylhydrocupreine Hydrochloride (optochin) is a reagent used in the alteration in bacterial morphology, it is now used in cell culture techniques for the presumptive identification of Streptococcus pneumoniae, which is optochin-sensitive, from other alpha-hemolytic streptococci such as viridans streptococci, which are resistant. However, a single standardized procedure does not exist. Optochin is included neither in the current EUCAST breakpoint tables nor in the CLSI performance standards for antimicrobial susceptibility testing.

(+)-Gallocatechin is a polyphenol, which occurs naturally in various plants, including green tea leaves.