Study on superposition law of drug bitterness based on tongue taste evaluation and electronic tongue evaluation

Abstract

Traditional Chinese medicine( TCM) decoction contains complex bitterness. In this paper,the simple mixing of TCM monomer bitter substances is used as the entry point to study the law of bitterness superposition. With berberine hydrochloride( alkaloids),geniposide( terpenoids),and arbutin( glycosides) as mother liquor,sophoridine( alkaloids),gentiopicroside( terpenoids),and puerarin( glycosides) as additive substances,these different additive substances were mixed with different mother liquor according to concentration gradients to form different liquid mixtures. The bitterness of the additive solution and the mixtures was evaluated by traditional human taste panel method( THTPM) and electronic tongue; the bitterness-concentration fitting model of the additive solution and the liquid mixtures was established by Weibull and logarithmic curves. By comparing and analyzing the bitterness-concentration model and the bitterness difference( ΔI_0/ΔI_e) of the additive solution and the mixture,the influence of mother liquor on the bitterness of the mixture was investigated. The results showed that both the additive solution bitterness model and the liquid mixture bitterness model were consistent with the Weibull model and the logarithmic model( THTPM: R~2≥0. 887 0,P<0. 01; electronic tongue test:R~2≥0. 753 2,P<0. 05). The fitting degree of the Weibull model was generally higher than that of the logarithmic model; the bitterness difference( ΔI_0) was monotonously decreasing; the fitting equation of tongue bitterness and electronic tongue bitterness: R~2≥0. 874 2,P<0. 01. In this article,through the superposition of different kinds of TCM bitter substances,THTPM and electronic tongue test was combined. It was found that the bitterness after superposition was still in Weibull or logarithmic relationship with the concentration of additive substances; THTPM showed that the effect of bitter mother liquor on the bitterness of the mixture decreased with the increase of the concentration of the additive; the bitterness of the electronic tongue was obviously related to the bitterness of THTPM. However,further verification is needed later by optimizing the concentration gradient and expanding the sample size.