ABSTRACT
A new, validated method, developed for the simultaneous determination of 16 phenolics [chlorogenic acid, scopoletin, vitexin, rutin, afzelin, isoquercitrin, narirutin, kaempferitrin, quercitrin, quercetin, kaempferol, chrysosplenol D, vitexicarpin, 5-hydroxy-3,3',4',7-tetramethoxy flavonoids, 5-hydroxy-3,4',6,7-tetramethoxy flavonoids and kaempferol-3,7,4'-trimethyl ether] in Houttuynia cordata Thunb. was successfully applied to 35 batches of samples collected from different regions or at different times and their total antioxidant activities [TAAs] were investigated. The aim was to develop a quality control method to simultaneously determine the major active components in H. cordata. The HPLC-DAD method was performed using a reverse-phase C[18] column with a gradient elution system [acetonitrilemethanol-water] and simultaneous detection at 345 nm. Linear behaviors of method for all the analytes were observed with linear regression relationship [r[2]>0.999] at the concentration ranges investigated. The recoveries of the 16 phenolics ranged from 98.93% to 101.26%. The samples analyzed were differentiated and classified based on the contents of the 16 characteristic compounds and the TAA using hierarchical clustering analysis [HCA] and principal component analysis [PCA]. The results analyzed showed that similar chemical profiles and TAAs were divided into the same group. There was some evidence that active compounds, although they varied significantly, may possess uniform anti-oxidant activities and have potentially synergistic effects
ABSTRACT
<p><b>OBJECTIVE</b>To investigate whether the gradually induced disordered occlusion can induce degenerative changes in rabbit TMJ.</p><p><b>METHODS</b>27 male New Zealand Rabbits, age of 5 months were divided equally and randomly into three groups: Group A: One premolar in upper dentition at one side and another premolar in lower dentition at the other side were pulled to move medially to the anterior intrinsic space by an orthodontic string to cause the corresponding premolars not to occlude with the opposites coincidently. Group B: the sham-operating controls, all animals were treated similar to those in Group A but without pulling. At the age of 6, 7 and 8 months, three rabbits of each group were killed by deeply anaesthetizing and bilateral condyles of TMJs were excised, sectioned and stained with HE.</p><p><b>RESULTS</b>There was no significant histological difference in condylar cartilage between Group B and C. The cartilage of TMJs condyle in Group A was found with significant degenerative changes that increased with age. The thickness of cartilage of anterior and intermediate part of condyles decreased, the disturbance of continuation of hypertrophic layer appeared and part of hypertrophic layer was locally replaced by fibrous tissue. While the thickness of cartilage of posterior part of condyle increased obviously with a significant increase of the proportion of immature chondrocytes.</p><p><b>CONCLUSION</b>The gradually induced disorder occlusion may lead to degenerative changes in rabbit condyle.</p>