ABSTRACT
AbstractThe demand for natural substances with anti-melanogenic activity is increasing due to the recent interest in skin whitening. Intensive investigation on the culture broth of Streptomyces sp. SCO-736, a marine bacterium from the Antarctica coast, has led to the isolation of a new natural product named antaroide (1). The chemical structure was established through the interpretation of MS, UV, and NMR spectroscopic data. Antaroide is a nine-membered macrolide with lactone and lactam moieties. To investigate its applicability in skin whitening cosmetics, its anti-melanogenic activity in B16F10 murine melanoma cells was examined. As a result, antaroide displayed strong inhibitory activities against melanin synthesis and also attenuated the dendrite formation induced by the α-melanocyte stimulating hormone (α-MSH). Antaroide suppressed the mRNA expression of the melanogenic enzymes such as tyrosinase, TRP-1 and TRP-2. This suggests that it may serve as a transcriptional regulator of melanogenesis. Collectively, the discovery of this novel natural nine-membered macrolide and its anti-melanogenic activity could give new insights for the development of skin whitening agents.
ABSTRACT
A new alpha-pyrone derivative, violapyrone J (1), and along with the two known violapyrones B (2) and C (3) were isolated from the fermentation broth of a marine actinomycete Streptomyces sp. SC0718. The structure of violapyrone J (1) was elucidated from 1D and 2D NMR spectroscopic analyses.
Subject(s)
Actinobacteria , Fermentation , StreptomycesABSTRACT
Campylobacter jejuni isolates from diarrhea patients and chickens in 2008 in Iksan, Korea were tested for biochemical characteristics, and for possession of genes hipO, mutated gyrA, and cdtB. Among the chickens tested 52% carried C. jejuni. All 28 patient isolates and 48 chickens isolates had typical biochemical characteristics, except for nalidixic acid resistance. All isolates from patients and chickens were resistant to ciprofloxacin, and had mutated gyrA gene indicating good correlation of the two tests. Analysis of pulsed-field gel electrophoresis (PFGE) pattern of SmaI-restricted DNA of 53 isolates showed 14 clusters. Twenty-eight patient isolates and two chicken isolates (57%) showed an identical pattern (cluster 9). Chicken isolates C37 and C48 (cluster 2), C31 and C33 (cluster 3), C29, C34, C35, and C36 (cluster 4), and C43, C44 (cluster 6) had identical patterns. All patient isolates, compared to 87% and 80% of chicken isolates, were susceptible to amikacin and chloramphenicol, respectively. Antibiotics with the lowest MIC90 were imipenem, gentamicin, and erythromycin, whereas, those with the highest were ampicillin and tetracycline. In conclusion, C. jejuni carriage rate of chickens in Iksan, Korea, was high, all 28 isolates from patients and two from chickens were an identical clone, whereas isolates from patients and remaining chickens were different clones with only 62% similarity, all isolates had hipO and cdtB genes, and all isolates were resistant to ciprofloxacin.