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Rice bran is an essential source of natural bioactive compounds with widely applications. This study aimed to determine the effects of extraction methods on the bioactivities of the extracts. Jasmine and Riceberry rice bran were extracted using 50% ethanolic maceration, cold pressed and subcritical dimethyl ether (DME) extraction. The extracts were analyzed for antioxidant, pro-collagen type I synthesis and 5α-reductase inhibition activities. The results showed that Riceberry rice bran extract exhibited superior antioxidant activity than Jasmine rice bran extract. The highest pro-collagen type I synthesis of Jasmine and Riceberry rice resulted from subcritical DME extraction (50.91%) and maceration (46.99%) respectively. It is a newly found that the subcritical DME extract of Jasmine rice bran displayed the strongest 5α-reductase inhibition activity (73.14 %inhibition) resulting from the biological markers linoleic acid (22.39±0.61 %w/w) and oleic acid (39.48±1.07 %w/w). Therefore, subcritical DME extraction is suitable for preparing rice bran extract for 5α-reductase inhibitor application.

Thai Traditional Medicine believes that human body is composed of four elements. It also mentions that skin problems related to each element can be alleviated by using suitable plants. This study aimed to determine the bioactivities related to skin effects of Aloe vera, Cucumis sativus, Alpinia galanga and Phyllanthus emblica. The plants were extracted with 50% ethanol prior to bioactivity evaluation. The highest anti-oxidant activity (IC50, 14.01 µg/ml) was found for P. emblica. Tyrosinase inhibition was found with P. emblica (41.92% inhibition) and A. vera (26.67% inhibition) at 500 µg/ml concentrations. The cells treated with 500 µg/ml A. vera and 15.62 µg/ml P. emblica had after 48 h increased collagen type-1 production by around 14 and 4 -fold from those of untreated cells. Anti-glycation was found with P. emblica. P. emblica, A. galanga and C. sativus at 62.5 µg/ml exhibited anti-inflammatory activity. This information supports evidence based use of these plants as food and cosmetic ingredients.

Dextran from Weissella confusa R003 isolated from sugar cane juice was purified and characterized. Dextran synthesis was performed by fermenting W. confusa R003 in MRS medium containing 10% (w/v) sucrose with continuous shaking at 125 rpm and at 30°C. For 24 hours, the 50% efficiency yield was obtained. Dextran in the culture medium was purified by ethanol precipitation. Structural analysis of dextran using 1H NMR, 13C NMR, and 2D NMR techniques showed the existence of glucoses with 97.4% α (1→6) linkage in the main chains and 2.6% α (1→3) in branches. The estimation of molecular weight by dynamic light scattering exhibited average molecular weight of 1.0 × 104 kDa. At low concentration (2.5% w/v), dextran behaved like liquid structure, while, increasing the concentration (5.0 and 10.0% w/v), it was revealed as viscoelastic behavior. The highest gelling phenomenon was found in the concentration of 10% w/v and at 37°C. Due to its production and properties, it may be suitable for commercial production and application in the field of foods as well as hydrogel.