| The research we have done before shows that the oiltea camellia extract owns extremely strong bioactivities like antioxidant activity, inhibiting the proliferation of tumor cells, reducing the weight and blood lipid of mice, regulating the blood sugar, improving the BPH symptoms, et al. This paper aims to analyze the bioactive compounds and antioxidant activity of extracts from the fruit shell of eight kinds of Camellia, the main contents and conclusions of this research are as follows:(1) The contents of saponin, polyphenols and flavones of eight kinds of oiltea camellia extracts{Camellia chekiangoleosa Hu, Camellia oleifera Abel., Camellia meiocarpa Hu, Camellia yuhsienensis Hu, Camellia semiserrata Chi, Camellia gigantocarpa Hu) was determined by the spectrophotometry method. The camellia saponin ranked the first among the bioactive compounds of the oiltea camellia extracts accounting for about30%, in which the saponin content of Camellia meiocarpa Hu was the highest. The oiltea camellia extracts was abundant in polyphenols, and the polyphenol content of Camellia oleifera Abel, was obviously higher than that of the others, on the contrary, the polyphenol content of Camellia semiserrata Chi and Camellia yuhsienensis Hu was the lowest. Compared with other bioactive compounds, the content of flavones was not that much, and the flavone content of Camellia chekiangoleosa Hu was the highest.(2) The characteristic polyphenol components of oiltea camellia extracts was identified as gallic acid (GA), ellagic acid (EA) and3-O-methylellagic acid4’-O-β-D-glucopyranoside (MEAG) by HPLC. Among eight kinds of oiltea camellia extracts, the total amount of the three compounds of Xianju Camellia oleifera Abel.was the highest, on the contrary, the extract of Camellia gigantocarpa Hu fruit shell didn’t contain the three compounds. The extract of Camellia chekiangoleosa Hu fruit shell was rich in GA, and the extract of Camellia semiserrata Chi fruit shell was abundant in MEAG.(3) The antioxidant activities of eight kinds of oiltea camellia extract was determined by DPPH assay, FRAP assay and the scavenging the harmful free radicals(H2O2, O2-,·OH) assay. The results of DPPH assay and FRAP assay were similar demonstrating that all kinds of oiltea camellia extracts owned strong antioxidant activities. The antioxidant activity of Camellia oleifera Abel, was stronger than that of the rest, especially the Xianju Camellia oleifera Abel, owning the strongest antioxidant activity (IC50of scavenging DPPH·=22.094±0.920μg/mL, FeSO4equivalent=0.1872±0.0011mmol/L), while, the antioxidant activities of Camellia chekiangoleosa Hu and Camellia semiserrata Chi was the weakest. The effect on scavenging the harmful free radicals (H2O2, O2-,·OH) was determined by the chemiluminescence method, and the results showed that the abilities of all kinds of oiltea camellia extracts to scavenge H2O2, O2-.·OH was much stronger than that of ascorbic acid, which was equal to that of Trolox. What’s more, based on the analysis of correlation between the antioxidant activities and the content of the bioactive susbstance, the results showed that the antioxidant activity was highly correlated with the content of total polyphenol, of which the correlation coefficients reached up to0.9.(4) The content of camellia tannins was determined by the casein method, and HPD100macroporous resin was chosen to purify the camellia tannins through some research. After treatment with macroporous resin HPD100, the content of camellia tannins was about4fold of that before purification with a yield of85%. The content of MEAG was increased2.3858±0.0035mg/g to11.0976±0.0056mg/g and the content of EA was increased from0.9279±0.0011mg/g to2.0338±0.0021mg/g by macroporous resin.(5) In mimic gastric juice, the scavenging effect of camellia tannins against nitrite was slightly weaker than that of ascorbic acid, when the concentration of camellia tannins was0.027mg/mL, the clearance rates was up to81.15%; the ability of camellia tannins to inhibit the nitrosamine synthesis was obviously stronger than that of ascorbic acid, when the concentration of camellia tannins was0.1350mg/mL, the inhibiting rate was up to75%. The ability of camellia tannins to scavenge nitrite and inhibit the nitrosamine synthesis was obviously stronger than that of crude oiltea camellia extracts.(6) The content of condensed camellia tannins was272.99±5.54mg/g on average determined by vanillin-sulfuric acid method at A500nm, which accounted for66.85percentage of the total camellia tannins. After acid hydrolysis, the content of camellia hydrolysable tannins was about135.36±2.54mg/g on average determined by HPLC, which accounted for33.15percentage of the total camellia tannins. Taking the above results into consideration, it demonstrated that the camellia tannins was a hybrid of condensed tannins and hydrolysable tannins, in which the condensed tannins played the vital role. |
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