Kanit Vichitphan

The characterisation of a novel Pichia anomala β-glucosidase with potentially aroma-enhancing capabilities in wine

The production and characterisation of β-glucosidase from an isolated yeast strain classified as aPichia anomala MDD24 were studied. The result shows that cellobiose is a good inducer for extracellular β-glucosidase production and optimum concentration is 1.5 percent cellobiose in yeast peptone dextrose medium. The purified β-glucosidase fromPichia anomala MDD24 exhibited a specific activity of 614±14 U mg−1 of protein and a molecular mass of 42 kDa. This enzyme was slightly inhibited by fructose and sucrose in the range of 4 to 20% (w/v). An ethanol concentration between 4 and 20% (v/v) activated β-glucosidase activity, at presence 16% (v/v) ethanol, β-glucosidases obtained maximum relative activity around 150%. The optimum pH and optimum temperature for β-glucosidase activity were 4.5 and 40 °C, respectively. Although the activity under the pH and temperature of wine production (pH 3.5–4.0 and 15–20 °C) was quite low, the enzyme was stable and the relative activities were higher than commercial enzyme under those conditions. The extracellular β-glucosidase fromPichia anomala MDD24 makes it possible to release glucosidically-bound monoterpenes, which are the major contributors to floral and fruity aromas in wines fromMuscat-type varieties, at final stage of alcoholic fermentation.

Supercritical CO2 for Efficient Extraction of Polymethoxyflavones in Kaempferia parviflora

To ensure polymethoxyflavone (PMF) extract from krachaidum, Kaempferia parviflora rhizome, supercritical CO2 extraction was attempted as an efficient and nontoxic method. Extraction yields and composition of PMFs in the supercritical fluid extracts (SFEs) were obtained under the different extraction conditions of pressure and temperature. Nine PMFs, including 5,7- dimethoxyflavone (1), 5,7,4’-trimethoxyflavone (2), 5,7,3’,4’-tetramethoxyflavone (3), 5-hydroxy-7- methoxyflavone (4), 5-hydroxy-3,7-dimethoxyflavone (5), 5-hydroxy-3,7,3’,4’-tetramethoxyflavone (6), 3,5,7-trimethoxyflavone (7), 3,5,7,4’-tetramethoxyflavone (8) and 3,5,7,3’,4’-pentamethoxyflavone (9), were isolated by vacuum liquid chromatography and characterized using various spectroscopic methods. The extraction yield by supercritical CO2 extraction was highest at 60°C and 300 bar, and the content of PMFs reached up to 85% in the SFEs.

Antiproliferative activity and polymethoxyflavone composition analysis of Kaempferia parviflora extracts

To investigate anticancer effects of Kaempferia parviflora, rhizomes of K. parviflora were extracted with supercritical CO2 fluid and ethanol under various extraction conditions. Antiproliferative activity of these extracts was evaluated against human cervical cancer HeLa and human gastric adenocarcinoma AGS cell lines. Supercritical CO2 fluid extracts (SFEs) of K. parviflora showed more potent antiproliferative activity than the ethanol extracts against both cell lines, because SFEs contained higher concentration of polymethoxyflavones (PMFs) (72–89 wt%) than the ethanol extract (55–70 wt%). From the compositional analysis of the extracts, 5,7-dimethoxyflavone (1) in K. parviflora was proposed as a potent anticancer PMF. Furthermore, it was found that PMFs with more methoxy groups do not necessarily show better anticancer activity.