ABSTRACT
Objective To investigate chemical constituents and new antimicrobial agents among essential oils from the rhizomes of Curcuma aeruginosa (C. aeruginosa) Roxb., Curcuma glans K. Larsen & J. Mood and Curcuma cf. xanthorrhiza Roxb. Methods The essential oils were obtained by hydro-distillation and analyzed by gas chromatography/mass spectroscopy. Agar-well diffusion assay was used to study the anti-microbial activity and also broth-micro dilution techniques were examined for minimum inhibitory concentration (MIC) against four bacterial strains and yeast. Results The gas chromatography/mass spectroscopy analysis showed monoterpenes predominantly (88.53%) in the rhizome oil of Curcuma cf. xanthorrhiza. Sesquiterpenes (50.10%) was the most abundant component in the essential oil of C. glans, while monoterpenes (45.55%) and sesquiterpenes (45.81%) were found in C. aeruginosa with a significant amount. The major components of C. aeruginosa were characterized as camphor (29.39%) and germacrone (21.21%). Germacrone (15.76%), β-pinene (9.97%) and camphor (9.96%) were found as major compounds in the rhizome oils of C. glans while α-terpinolene (24.86%) and p-cymen-7-ol (12.17%) were found as major compositions in Curcuma cf. xanthorrhiza. The essential oils were tested against four bacterial strains and yeast. As a result, the rhizome oil of C. aeruginosa exhibited potent activity against Staphylococcus aureus [inhibition zone (21.94 ± 0.24) mm, MIC 125 μg/mL], Bacillus cereus [inhibition zone (20.83 ± 0.36) mm, MIC 125 μg/mL], and Candida albicans [inhibition zone (11.60 ± 0.30) mm, MIC 250 μg/mL]. Conclusions The essential oils from three Curcuma species possessed greater activity against the gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) than gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa). The results suggest that the essential oils from the fresh rhizome of Curcuma spp. might be a potential source of natural antimicrobial substances.
ABSTRACT
Objective To study some soybean cultivars commonly used in Northern Thailand that exhibit high nutritional profile and to investigate the changes in bioactive principles and antioxidant capacity of the fermented soy broth that was prepared using the selected soybean cultivar and Lactobacillus paracasei HII02 mediated fermentation process. Methods The best soybean cultivar was subjected to fermentation, and then analyzed the phytochemical, antioxidant and nutritional changes by high performance liquid chromatography and spectrophotometric analysis. Results Sor Jor 2 soybean cultivar showed rich nutritional profile and was subjected to fermentation process. Lactobacillus paracasei HII02 mediated fermentation of Sor Jor 2 soybean exhibited stable physical and chemical characteristics. Lactic acid bacteria mediated fermentation also increased the aglycone forms of isoflavone content, exhibited antioxidant capacity and thereby enhanced the quality of the fermented soy broth. It also prevented the growth of coliforms in fermented soybean. Conclusions The study results suggest that fermented soybean is rich in nutrition and considered to be safe for consumption for the improvement of health and to treat the malnutrition.