Physicochemical and biological properties of encapsulated Boesenbergia rotunda extract with different wall materials in enhancing antioxidant, mineralogenic and osteogenic activities of MC3T3-E1 cells.

Boesenbergia rotunda (L.) comprises bioactive compounds with biological and pharmacological properties, especially flavonoid compounds with osteoblastogenesis-stimulating potential. However, the application of B. rotunda in the food and pharmaceutical industry is restricted by its low solubility and stability. Encapsulation becomes an alternative to overcome these restrictions. The purpose study was to encapsulate B. rotunda extract by freeze-drying and to investigate the effects of different wall materials (maltodextrin (MD), gum arabic (GA), and their combination (MDGA)) and extract contents on the physicochemical, bioactive properties and in vitro enhancement of osteogenesis of MC3T3-E1 cells of the obtained encapsulates. The results revealed that encapsulated B. rotunda can reduce cytotoxicity, enhance biological activity, and maintain the stability of bioactive compounds. The MD was a good wall material for yield percentage. However, the values of moisture content Aw, and solubility among all the encapsulated powders were no significant differences, with all encapsulated powders having similar structures based on scanning electron microscopy. Fourier transform infrared spectroscopy confirmed the extract was encapsulated by the selected wall materials. Combining the MD and GA encapsulation agents afforded the best protection of the bioactive compounds, increasing EE (MDGA-7 > MDGA-5), pinostrobin content, TPC, and antioxidant activities (MDGA-5 > MDGA-7). The MDGA-5 and MDGA-7 at 10-50 µg/mL were not toxic to cells and promoted MC3T3-E1 cell viability, while also enhancing the Alkaline phosphatase activity, and promoting matrix mineralization of pre-osteoblast MC3T3-E1 cells after 21 and 28 days. This result showed that MDGA was a suitable wall material for B. rotunda encapsulations and a potential source of bioactive ingredients that could applied in food or pharmaceutical products for osteoporosis prevention.

Boosting the Antibacterial Performance of Natural Rubber Latex Foam by Introducing Silver-Doped Zinc Oxide.

Natural rubber (NR) latex foam is one of the rubber products that are increasingly in demand in the market. This is simply because of its lightweight, good thermal insulation, and resilience. The applications of NR latex foam are mostly for pillows and mattresses. This has resulted in these products requiring antibacterial performance which is very important for the safety of the end-users. In this study, the antibacterial NR latex foam was prepared by incorporating the silver-doped zinc oxide (Ag-doped ZnO) into the NR latex foam. Ag-doped ZnO was prepared by microwave-assisted method and then characterized through morphological characteristics and X-ray diffraction (XRD). The content of Ag doped onto ZnO was designed by varying the AgNO3 content at 15 wt%, 50 wt%, and 100 wt% of ZnO. The results confirmed that the Ag was successfully doped onto ZnO. The silver particles were found to be in the 40-50 nm range, where the size of ZnO ranges between 300 and 400 nm, and the Ag attached to the ZnO particles. The XRD patterns of Ag-doped ZnO correspond to planes of hexagonal wurtzite ZnO structure and cubic metallic Ag. This Ag-doped ZnO was further added to NR latex foam. It was observed that Ag-doped ZnO did not affect the physical properties of the NR latex foam. However, it is clear that both the inhibition zone and percent reduction of bacteria (e.g., E. coli and S. aureus) were enhanced by the addition of Ag-doped ZnO. It showed a decrease in the amount of cell growth over contact time. The content of 100 wt% AgNO3 could reduce E. coli and S. aureus up to 64.72% and 58.90%, respectively, when samples were maintained for 24 h. This study provides a scientific understanding of how Ag-doped ZnO could facilitate the development of eventual rubber foam products based on the respective results.

Antagonistic Potential of Soil Streptomyces Isolates from Southern Thailand to Inhibit Foodborne Bacterial Pathogens.

Streptomyces are well known for their competence to produce thousands of bioactive secondary metabolites and enzymes. This study aimed to assess the inhibitory activities of crude extracts from diverse Streptomyces collected from rice soils in Narathiwat, Thailand, against foodborne bacterial pathogens. In total, 136 Actinomycete isolates were screened using a cross-streak method for the ability to produce effective metabolites against 5 pathogenic bacteria. Out of these, 19 (13.97%) isolates had antibacterial activity against at least one tested bacterium. Most of the isolates could strongly suppress the growth of S. aureus ATCC25923 and B. cereus MTCC430 except P. aeruginosa ATCC27853. On the basis of morphological, cultural, and biochemical characteristics, all potent isolates exhibited typical features that fitted the genus Streptomyces. Two of the 7 selected ethyl acetate crude extracts had good antagonistic activity against S. aureus ATCC25923 and B. cereus MTCC430 when tested using the agar well diffusion assay. Furthermore, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of the 2 extracts evaluated using the colorimetric broth microdilution method ranged from 256 to >1,024 µg/ml against the tested bacteria. The partial nucleotide sequences of the 16S rRNA gene led to identifying both active isolates as Streptomyces species. These active Streptomyces isolates could provide an interesting source for generating innumerable natural compounds with antibacterial activity that can presumably be developed to fight bacterial pathogens in the near future.

Approach toward enhancement of halophilic protease production by Halobacterium sp. strain LBU50301 using statistical design response surface methodology.

A new potent halophilic protease producer, Halobacterium sp. strain LBU50301 was isolated from salt-fermented fish samples (budu) and identified by phenotypic analysis, and 16S rDNA gene sequencing. Thereafter, sequential statistical strategy was used to optimize halophilic protease production from Halobacterium sp. strain LBU50301 by shake-flask fermentation. The classical one-factor-at-a-time (OFAT) approach determined gelatin was the best nitrogen source. Based on Plackett-Burman (PB) experimental design; gelatin, MgSO4·7H2O, NaCl and pH significantly influenced the halophilic protease production. Central composite design (CCD) determined the optimum level of medium components. Subsequently, an 8.78-fold increase in corresponding halophilic protease yield (156.22 U/mL) was obtained, compared with that produced in the original medium (17.80 U/mL). Validation experiments proved the adequacy and accuracy of model, and the results showed the predicted value agreed well with the experimental values. An overall 13-fold increase in halophilic protease yield was achieved using a 3 L laboratory fermenter and optimized medium (231.33 U/mL).