Characterization and comparison of the pungent components in commercial Zanthoxylum bungeanum oil and Zanthoxylum schinifolium oil.

In the present study, the characterization and comparison of the pungent components in commercial Z. bungeanum oils and Z. schinifolium oils were investigated. By high-performance liquid chromatography (HPLC)-mass spectrometry (MS/MS) analysis, the major alkylamides in Z. bungeanum and Z. schinifolium oils were identified as hydroxy-ε-sanshool, hydroxy-α-sanshool, hydroxy-ß-sanshool, hydroxy-γ-sanshool, hydroxy-γ-isosanshool, bungeanool, isobungeanool, and tetrahydrobungeanool, respectively. Hydroxy-α-sanshool was found to be the most abundant alkylamide in all oils. The levels of hydroxy-ε-sanshool and hydroxy-ß-sanshool in Z. bungeanum oils were comparable to that in Z. schinifolium oils, whereas Z. bungeanum oils contained significantly (P less than 0.05) higher levels of hydroxy-γ-isosanshool, bungeanool, isobungeanool, and tetrahydrobungeanool, compared with Z. schinifolium oils. Furthermore, principal component analysis (PCA) indicated that Z. bungeanum oil and Z. schinifolium oil were clearly classified by HPLC fingerprinting profiles and concentrations of alkylamides. In addition, the results of PCA suggested that alkylamides, such as hydroxy-γ-sanshool and bungeanool, could be potential markers to distinguish Z. bungeanum oil and Z. schinifolium oil. The results from this study could be used to discriminate the different flavor characterization and control the quality of commercial Z. bungeanum oil and Z. schinifolium oil.

Anti-hyperglycemic effect of chebulagic acid from the fruits of Terminalia chebula Retz.

In the present study, we firstly compared rat intestinal α-glucosidase inhibitory activity by different ethanol-aqueous extractions from the dried fruits of Terminalia chebula Retz. The enzymatic assay showed that the 80% ethanol extract was more potent against maltase activity than both 50% and 100% ethanol extracts. By HPLC analysis, it was determined that the 80% ethanol extract had a higher content of chebulagic acid than each of 50% or 100% ethanol extract. Next, we investigated how efficiently chebulagic acid could inhibit sugar digestion by determining the glucose level on the apical side of the Caco-2 cell monolayer. The result showed that the maltose-hydrolysis activity was down-regulated by chebulagic acid, which proved to be a reversible inhibitor of maltase in Caco-2 cells. On the other hand, chebulagic acid showed a weak inhibition of sucrose-hydrolysis activity. Meanwhile, chebulagic acid did not have an obvious influence on intestinal glucose uptake and was not effective on glucose transporters. Further animal studies revealed that the oral administration of chebulagic acid (100 mg/kg body weight) significantly reduced postprandial blood glucose levels by 11.1% in maltose-loaded Sprague-Dawley (SD) rats compared with the control group, whereas the oral administration of chebulagic acid did not show a suppressive effect on postprandial hyperglycemia in sucrose- or glucose-loaded SD-rats. The results presented here suggest that chebulagic acid from T. chebula can be used to control blood glucose and manage type 2 diabetes, although clinical trials are needed.

Chemical composition and antimicrobial activity of the essential oil of kumquat (Fortunella crassifolia Swingle) peel.

The aim of this study was to determine the main constituents of the essential oil isolated from Fortunella crassifolia Swingle peel by hydro-distillation, and to test the efficacy of the essential oil on antimicrobial activity. Twenty-five components, representing 92.36% of the total oil, were identified by GC-MS analysis. The essential oil showed potent antimicrobial activity against both Gram-negative (E. coli and S. typhimurium) and Gram-positive (S. aureus, B. cereus, B. subtilis, L. bulgaricus, and B. laterosporus) bacteria, together with a remarkable antifungal activity against C. albicans. In a food model of beef extract, the essential oil was observed to possess an effective capacity to control the total counts of viable bacteria. Furthermore, the essential oil showed strongly detrimental effects on the growth and morphological structure of the tested bacteria. It was suggested that the essential oil from Fortunella crassifolia Swingle peel might be used as a natural food preservative against bacteria or fungus in the food industry.

Chemical composition, antimicrobial and antioxidant activities of essential oil from Gnaphlium affine.

The chemical composition of the essential oil from Gnaphlium affine was determined, and its antimicrobial and antioxidant activities were evaluated. Twenty-four compounds, representing 94.95% of the amount of total oil, were identified by gas chromatography-mass spectrometry (GC-MS) analysis. Main constituents of the essential oil were found to be eugenol (18.24%), linalool (10.62%), trans-caryophyllene (8.86%), α-terpineol (5.97%), p-cymene (5.75%), hexadecanoic acid (5.63%), γ-cadinene (4.98%), δ-cadinene (4.22%), α-humulene (3.22%), and (-)-ß-elemene (3.15%). The essential oil revealed a remarkable antimicrobial effect against the tested food-borne microorganisms with the MIC and MBC values in the ranges of 0.2-1.56 µg/ml and 0.39-3.13 µg/ml, respectively. The essential oil showed a potent antioxidant activity in ABTS radical scavenging, lipid peroxidation and reducing power assay. It was suggested that the essential oil from G. affine may be a new potential source as natural antimicrobial and antioxidant agents applied in food systems.