[Objectives] The biologically active compounds of Houttuynia cordata Thunb. as a medicinal and edible plant are well documented. However, amino acid as an important indicator of the value of H. cordata is little reported. [Methods] Amino acids of the H. cordata were analysed by pre-column derivatization with 2,4-dinitrochlorobenzne(CDNB) coupled to HPLC/DAD. The optimized conditions of the amino acids derivatized by CDNB were followed: 110 ℃ of hydrolysis temperature, 1∶12 of the equivalent proportion between amino acid and CDNB, 80 min of derivatization reaction time and 80 ℃ of derivatization reaction temperature. The method was used to determine the amino acids of H. cordata samples from 11 different geographical sites in Guizhou. [Results] The results suggested that the contents of 17 amino acids were quite variable at different H. cordata samples. [Conclusions] This study will provide a basis for the quality evaluation of H. cordata nutrition.
Xuan FENGZhannan YANGZhu ZHENGJuan HUXiaofang WEIHonghao HUOCheng ZHAOQuling ZHANG
[Objectives] To evaluate the phenolic components of Houttuynia cordata Thunb. and their antioxidant activities from different sources. [Methods] Samples of 35 different sources of H. cordata were collected from Guizhou,and polyphenols,total flavonoids,total chlorogenic acid and 7 kinds of flavonoids( xanthol-3-O-glucoside,hyperoside,quercitrin,rutin,quercetin,kaempferol and isorhamnetin),and DPPH free radical scavenging rate of the extracts were determined. Relationship between the contents of phenolics and the DPPH free radical scavenging rate of the extracts were analyzed by SPSS software. [Results] There were some significant differences in polyphenols,total flavonoids,total chlorogenic acid and the seven flavonoids between samples of different habitats,and the contents of polyphenols,total flavonoids and total chlorogenic acid increased linearly with altitude. There was a significant positive correlation between polyphenols,total flavonoids and total chlorogenic acid content and DPPH free radical scavenging rate of extracts. The contents of kaempferol-3-O-glucoside,hyperoside,quercitrin,rutin,quercetin kaempferol and isorhamnetin were positively correlated with the DPPH free radical scavenging rates of the extracts,except for the significant correlation with quercitrin. [Conclusions]The experimental results suggest that the antioxidant capacity of H. cordata is derived from the total contribution of the phenolic components,indicating that these components have overall equivalence of antioxidant capacities. This provides a new research idea for solving the key problems of quality control of traditional Chinese medicine.
