The properties of intracellular b-glucosidases produced from two yeast isolates identified as Hanseniaspora sp. BC9 and Pichia anomala MDD24 were characterized. b-Glucosidase from Hanseniaspora sp. BC9 was not inhibited by both 20% w/v fructose and 20% w/v sucrose and was slightly inhibited by glucose ([ 40% relative b-glucosidase activity with 10% w/v glucose). b-Glucosidase from P. anomala MDD24 was inhibited by glucose, fructose and sucrose. In the presence of 4-12% v/v ethanol, b-glucosidase from P. anomala MDD24 was stimulated in range 110-130% relative activity whereas b-glucosidase from Hanseniaspora sp. BC9 was substantially inhibited in the presence of ethanol. Finally, juice and wine of the Muscat-type grape variety, Traminette, were selected to determine sugar-bound volatile aroma release, particularly terpenes, by the activity of those b-glucosidases. The results showed that high concentration of free aroma compounds were detected from Traminette juice treated with b-glucosidase from Hanseniaspora sp. BC9and Traminette wine treated with b-glucosidase from P. anomala MDD24. The preliminary results with proposed an application of these enzymes in commercial wine production lead to more efficient of b-glucosidase from Hanseniaspora sp. BC9 in releasing desirable aromas during an early stage of alcoholic fermentation while b-glucosidase from P. anomala MDD24 is suitable at the final stage of alcoholic fermentation.

-The production and characterisation of β-glucosidase from an isolated yeast strain classified as a Pichia 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 from Pichia 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 from Pichia anomala MDD24 makes it possible to release glucosidically-bound monoterpenes, which are the major contributors to floral and fruity aromas in wines from Muscat-type varieties, at final stage of alcoholic fermentation.

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A new yeast species (KKU-FW10) belonging to the Candida genus was isolated from Jasminum adenophyllum in the Plant Genetic Conservation Project under The Royal Initiative of Her Royal Highness Princess Maha Chakri Sirindhorn area, Chulabhorn Dam, Konsan district within Chaiyaphum province in Thailand. The strain was identified via analysis of nucleotide sequences from the D1/D2 domain of 26S ribosomal DNA and based on its morphological, physiological and biochemical characteristics. The sequence obtained from yeast isolate KKU-FW10 was 97 percent identical to that of Candida chanthaburiensis (GenBank accession number AB500861.1), with 506/517 (nucleotides identity/total nucleotides) matching nucleotides, nine substitutions and two gaps being detected. This species belonged to the Candida clade. Regarding morphological characteristics, isolate KKU-FW10 presents cream-colored butyrous colonies, vegetative reproduction through budding and, round cells without filaments or ascospores. The major ubiquinone detected was Q-9. The above results suggest that isolate KKU-FW10 is a new member of the genus Candida, and the name Candida konsanensis is proposed for this yeast. The type strain of the new species is KKU-FW10(T) (= BCC 52588(T), = NBRC 109082(T), = CBS 12666(T)). In addition, this KKU-FW10 could potentially produce 58.24 Units/ml of carboxymethyl cellulase when it was cultured in YP broth containing 1.0 % carboxymethyl cellulose for 24 h.

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Tyrosinase (TYR) is a type III copper oxidase present in fungi, plants and animals. The inhibitor of human TYR plays a vital role in pharmaceutical and cosmetic fields by preventing synthesis of melanin in the skin. To search for an effective TYR inhibitor from various plant extracts, a kinetic study of TYR inhibition was performed with mushroom TYR. Among Panax ginseng, Alpinia galanga, Vitis vinifera and Moringa oleifera, the extracts of V. vinifera seed, A. galanga rhizome and M. oleifera leaf reversibly inhibited TYR diphenolase activity with IC50 values of 94.8 ± 0.2 µg/mL, 105.4 ± 0.2 µg/mL and 121.3 ± 0.4 µg/mL, respectively. Under the same conditions, the IC50 values of the representative TYR inhibitors of ascorbic acid and kojic acid were found at 235.7 ± 1.0 and 192.3 ± 0.4 µg/mL, respectively. An inhibition kinetics study demonstrated mixed-type inhibition of TYR diphenolase by A. galanga and V. vinifera, whereas a rare uncompetitive inhibition pattern was found from M. oleifera with an inhibition constant of Kii 73 µg/mL. Phytochemical investigation by HPLC-MS proposed luteolin as a specific TYR diphenolase ES complex inhibitor, which was confirmed by the inhibition kinetics of luteolin. The results clearly showed that studying TYR inhibition kinetics with plant extract mixtures can be utilized for the screening of specific TYR inhibitors.

The current trend worldwide is searching plant extracts towards prevention of neurodegenerative disorders. This study aimed to investigate the neuroprotective effect of Alpinia galanga leaves (ALE), Alpinia galanga rhizomes (ARE), Vitis vinifera seeds (VSE), Moringa oleifera leaves (MLE), Panax ginseng leaves (PLE) and Panax ginseng rhizomes (PRE) ethanolic extracts on human neuroblastoma (SHSY5Y) cells. The 1-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging of VSE and MLE were 81% and 58%, respectively. Ferric-reducing antioxidant power (FRAP) of ALE and MLE (33.57 ± 0.20 and 26.76 ± 0.30 μmol Fe(ΙΙ)/g dry wt., respectively) were higher than for the other extracts. Liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF/MS) revealed MLE active compounds. Intracellular study by nitro-blue tetrazolium (NBT) test showed that MLE and VSE had high O2− scavenging (0.83 ± 0.09 vs. 0.98 ± 0.08 mg/mL, respectively). MLE had the highest ROS scavenging followed by PRE (0.71 ± 0.08 vs. 0.83 ± 0.08 mg/mL, respectively), by 2,7-dichlorodihydrofluorescein diacetate (DCFHDA) assay. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) cytotoxicity and neuroprotection tests on SHSY5Y showed that PRE had a better neuroprotective effect but higher cytotoxicity compared to MLE (viable cells 51% vs. 44%, IC50 1.92 ± 0.04 vs. 2.7 ± 0.2 mg/mL, respectively). In conclusion, among the studied plants, MLE has potential for developing as a neuroprotective agent.

Objective: Thai medicinal plants were used as the traditional medicines and as part of everyday plants diet. Plants contain a mixture of phytochemical and exhibit a lot of functional food and medicinal properties. This project aims to investigate the potential of selected Thai medicinal plants according to the properties of their antioxidant and antibacterial activities. Methods: The eighteen plants were extracted using maceration method with 95% ethanol. The antioxidant activity was evaluated by DPPH and FRAP assay. The total phenolic content was evaluated by Folin-Ciocalteu phenol reagent. The antibacterial activity was evaluated by agar disc diffusion method. The extract which exhibited high antioxidant and antibacterial activity was selected to observe morphological changes by the scanning electron microscope (SEM). Results: The extract of Caesalpinia sappan showed the highest activities on both antioxidant assayed by FRAP method and total phenolic contents, however, exhibited high antioxidant assayed by DPPH compared to Bauhinia strychnifolia extract. Moreover, the extract of C. sappan showed the excellent antibacterial activities against six pathogenic bacteria in Gastro-intestinal tract. The morphological change by SEM was selected for further investigation antibacterial activities of C. sappan extract. The results showed that the inhibitory effect to those bacterial strains could be caused by the disruption of the cell membrane and decrease biofilm formation after treatment with the extract. Conclusion: The ethanol extract of C. sappan exhibited strong antioxidant and antibacterial activities against the six pathogenic bacteria. This result suggested that C. sappan could be applied to use for medicinal purpose and functional products. Key words: Antioxidant activity, Antibacterial activity, Total phenolic content, Caesalpinia sappan, Scanning electron microscope. 11,12,13 Previous studies showed the possibility to use many Thai plants as antioxidants and antibacterial agents. Some Thai plant extracts such as Cassia siamea, Garcinia cowa, Limnophila aromatica, Polygonum odoratum, Dioscorea bulbifera, Syzygium cumini and Zingiber zerumbet which have been reported for their antioxidant activities, and these plants also exhibit antibacterial against some pathogenic bacteria. 14,15,16,17 However, there are many medicinal Thai plants which are not to be evaluated their antioxidant related to antibacterial activities from GI tract. Due to the abovementioned facts, this project aims to investigate the potential of Thai plants according to the properties of the plant extracts on their antioxidant and antibacterial activities including their effects on morphological changes of selected pathogenic bacteria in GI tract. This information will be used as guide line for development of medicinal products and functional ingredients for use in novel functional food products. Parichat MATERIALS AND METHODS Sample collectionEighteen plant samples were selected based on Thai traditional medicine and their health pro...