Essential oils and ethanol extract from Camellia nitidissima and evaluation of their biological activity.

Camellia nitidissima, a well-known species of yellow Camellia, has undergone commercial cultivation as a new tea resource recently. Herein, the composition, antioxidant and antimicrobial activities of the essential oil and ethanol extract of C. nitidissima were investigated. The essential oils from the leaves and flowers of C. nitidissima were obtained by hydro-distillation. A total of 56 and 34 constituents accounting for 77.5 and 96.8% of the oils were identified by GC-MS. Linalool (35.8%), phytol (7.9%), cis-geranyl acetone (7.3%) and methyl salicylate (6.8%) were found to be the primary components in the leaf oil, while the flower oil was rich in α-eudesmol (34.3%), γ-eudesmol (31.5%) and linalool (11.1%). The ethanol extract of C. nitidissima leaves contained 281.04 mg gallic acid equivalent/g of total phenols. The antioxidant activities of the two oils and extract were evaluated by DPPH and ABTS radical-scavenging assays. The IC50 values varied from 17.4 (extract) to 720.3 µg/mL (flower oil) for DPPH and from 28.8(extract) to 889.6 µg/mL (flower oil) for ABTS. Both essential oils exhibited moderate antioxidant activities, and the extract possessed strong effects close to ascorbic acid. Additionally, the antimicrobial activities of the oils and extract against Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa were evaluated by agar dilution assay. No considerable bactericidal activities were observed for either essential oil or extract compared with ampicillin and tobramycin standards. The results indicated the extract was more efficient than the two essential oils against S. aureus (MIC = 0.625 mg/mL) and B. subtilis (MIC = 1.25 mg/mL).

Ultrasonic degradation of aqueous dextran: effect of initial molecular weight and concentration.

Seven dextrans with different initial molecular weight (IMW) were depolymerized by ultrasonic treatment. The effects of IMW in a wide range from 9.3×10(3) Da to 1.7×10(6) Da and solution concentration (1, 10 and 20 mg/mL) on dextran degradation were investigated. Changes in weight-average molecular weight (Mw) and polydispersity index (D value) were monitored as a function of ultrasonic time. Results showed that Mw and D value decreased with increasing time of ultrasonic treatment. Moreover, the degradation proceeded faster for higher IMW dextrans and more dilute solutions, yielding lower molecular weight dextrans and more homologous solutions. Percentage variation of dextran fragments at different molecular weight divisions showed that most of the degradation took place in larger molecular weight fragments. Ultrasonic treatment is a simple and controllable method for producing dextrans with low molecular weight, which are more suitable for clinical use.

[Studies on fingerprints of ant nest of Macrotermes annadalei from different areas].

OBJECTIVE: To study comparatively the fingerprint of zhuang medicinal material-ant nest of Macrotermes annadalei from different areas in Guangxi. METHOD: The fingerprint of total amino acid of 12 lots of ant nest of M. annadalei from different areas was determined by high speed amino acid analyzer. Separation was perform on anylytical column (4.6 mm x 40 mm), column temperature at 57 degrees C. The flow rate of buffering solution was 0.4 mL x min(-1), and the flow rate of ninhydrin was 0.3 mL x min(-1). RESULT: 18 characteristic peaks in the fingerprints were identified in 12 lots of samples, the chromatographic overlap rate was 89.4%-100.0%, and the total relative peak area of 7 lots of samples was over 52% in eight main peaks. CONCLUSION: The components of amino acid of ant nest of M. armadalei from different areas in Guangxi are very similar. The qualities of majority samples are good as well. The fingerprints can provide the useful information for the quality evaluation and the identification of ant nest of M. annadalei.

[Study on the quality of Rhizome of Dioscorea persimilis].

OBJECTIVE: To evaluate the quality of Rhizome of D. persimilis Prain et Burk. METHODS: Determined the contents of 6 qualitative indexes in samples of Rhizome of D. persimilis Prain et Burk that were cultivated in Yongning, Bobai, Beiliu, Guiping and Rongxian of Guangxi and in sample of Rhizome of Dioscorea opposita Thunb, that was cultivated in Wenxian, Henan province. RESULTS: The contents of water in them (%): 15.39, 18.52, 15.41, 13.96, 15.48, 15.74; the contents of protein in them (%): 7.06, 8.45, 9.20, 9.67, 8.63, 9.79; the contents of starch in them (%): 84.51, 86.51, 82.72, 83.65, 84.19, 79.13; the contents of water extracts in them (%): 6.19, 6.98, 8.95, 7.41, 6.70, 9.40; 90% EtOH extracts in them (%): 2.00, 2.04, 2.68, 2.20, 2.11, 3.53; the contents of 18 kinds of amino acids in them (%): 5.23, 6.31, 6.22, 6.78, 6.59, 6.83. CONCLUSION: The quality of Rhizome of D. persimilis Prain et Burk cultivated in Guiping or Beiliu is beter than that of Rhizome of D. persimilis Prain et Burk cultivated in Yongning. The quality of Rhizome of D. persimilis Prain et Burk cultivated in Rongxian or Bobai are between those of Rhizome of D. persimilis Prain et Burk cultivated in Guiping or Beiliu and Rhizome of D. persimilis Prain et Burk cultivated in Yonging. The qualities of Rhizome of D. persimilis Prain et Burk cultivated in Guiping or Beiliu are similar to that of Yam.