Abstract
A titration method for the determination of lipoic acid using Streptococcus faecalis R was investigated. The medium used for Streptococcus faecalis 10C1 was also applied which showed a better sensitivity for growth of Stc. faecalis R than that of Stc. faecalis 10C1. A suitable standard response curve after 24 hour incubation was ranged from 0.025 to 0.5mμg/ml. Growth stimulating activity of some lipoic acid derivatives was also examined. Assay for lipoic acid in natural materials gave a satisfactory result in urine, however, those in blood and liver were varried to some extent depending on the extraction methods and dilution of samples.
