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[Objective] To research the effects of hydrochloric acid hydrolysis extraction on the antioxidant and antimicrobial activities of tannin extracts from Castanea mollissima,Cyclobalanopsis glauca and Quercus aliena. [Methods] Extracts from C. mollissima,C. glauca and Q. aliena were prepared by water extraction( WE) and ethanol extraction( EE) and HCl( 4 M) hydrolysis extraction( HE),respectively.Their DPPH radical scavenging capabilities,antimicrobial activities and gallic acid contents( GAC) were detected as well as the soluble tannin contents in dry leaves.[Results]The soluble tannin contents in C. mollissima,C. glauca and Q. aliena leaves were 87. 32,76. 89 and 51. 28 mg / g,respectively. HE increased the GAC in the extracts of C. mollissima and C. glauca by 15- 60 and 5- 15 times,respectively,while the GAC in the extracts of Q. aliena remained almost unchanged when compared with WE and EE. Meanwhile,the DPPH scavenging capabilities and antimicrobial activities were also enhanced by HE. C. albicans and C. tropicalis were more sensitive than others to the three plant extracts,especially to C. glauca. Unexpectedly,C. glauca had the highest antimicrobial activity,but its tannin and gallic acid contents were only moderate,indicating that other substance with higher antimicrobial activity existed. [Conclusions]HE enhanced the antioxidant and antimicrobial activities of tannin rich extracts of the three plant leaves from the Fagacae family.
[Objective] To research the effects of hydrochloric acid hydrolysis extraction on the antioxidant and antimicrobial activities of tannin extracts from Castanea mollissima, Cyclobalanopsis glauca and Quercus aliena. [Methods] Extracts from C. mollissima, C. glauca and Q. aliena were prepared by water extraction (WE) and ethanol extraction (EE) and HCl (4 M) hydrolysis extraction (HE), respectively.Their DPPH radical scavenging capabilities, antimicrobial activities and gallic acid contents (GAC) were detected as well as the soluble tannin contents in dry leaves. [Results] The soluble tannin contents in C. mollissima, C. glauca and Q. aliena leaves were 87. 32,76. 89 and 51. 28 mg / g, respectively. HE increased the GAC in the extracts of C mollissima and C. glauca by 15- 60 and 5- 15 times, respectively, while the GAC in the extracts of Q. aliena with almost balanced when compared with WE and EE. Meanwhile, the DPPH scavenging capabilities and antimicrobial activities were also also enhanced by H EC albicans and C. tropicalis were more sensitive than others to the three plant extracts, especially to C. glauca. Unexpectedly, C. glauca had the highest antimicrobial activity, but its tannin and gallic acid contents were only moderate, indicating that the other substance with higher antimicrobial activity existed. [Conclusions] HE enhanced the antioxidant and antimicrobial activities of tannin rich extracts of the three plant leaves from the Fagacae family.