Evaluation and enzyme-aided enhancement of anti-photoaging properties of Camellia japonica in UVA-irradiated keratinocytes.

Exposure to ultraviolet (UV) radiation is the main reason behind extrinsic skin aging. Changes due to chronic UV exposure are called photoaging. Natural products are effective ingredients against UV-mediated skin damage. Present study investigated the anti-photoaging properties of Camellia japonica flowers which possess various bioactivities. To enrich the extracts of C. japonica flowers, pectinase and beta-glucosidase treatment was employed. Anti-photoaging effect was screened using the changes in MMP-1 and collagen levels in UVA-irradiated human HaCaT keratinocytes. The crude extract of C. japonica flowers (CE) was shown to decrease the UVA-induced MMP-1 secretion while attenuating the collagen levels. Pectinase and beta-glucosidase treated CE (ECE) showed increased anti-photoaging effects against UVA-induced changes in MMP-1 and collagen production. Camellenodiol (CMD), a known triterpenoid from C. japonica, isolated as the active ingredient of ECE and its anti-photoaging effect was screened. Results showed that CMD ameliorated the UVA-induced deterioration in collagen levels by suppressing MMP-1 production in transcriptional level. CMD treatment downregulated the phosphorylation of p38, ERK, and JNK MAPKs along their downstream effectors, c-Fos, and c-Jun. In conclusion, enzyme-assisted extraction of C. japonica flowers was suggested to enhance the anti-photoaging properties suggestively through high bioactive content such as CMD.

Conservation of thiol-oxidative stress responses regulated by SigR orthologues in actinomycetes.

Numerous thiol-reactive compounds cause oxidative stress where cells counteract by activation of survival strategies regulated by thiol-based sensors. In Streptomyces coelicolor, a model actinomycete, a sigma/antisigma pair SigR/RsrA controls the response to thiol-oxidative stress. To unravel its full physiological functions, chromatin immuno-precipitation combined with sequence and transcript analyses were employed to identify 108 SigR target genes in S. coelicolor and to predict orthologous regulons across actinomycetes. In addition to reported genes for thiol homeostasis, protein degradation and ribosome modulation, 64 additional operons were identified suggesting new functions of this global regulator. We demonstrate that SigR maintains the level and activity of the housekeeping sigma factor HrdB during thiol-oxidative stress, a novel strategy for stress responses. We also found that SigR defends cells against UV and thiol-reactive damages, in which repair UvrA takes a part. Using a refined SigR-binding sequence model, SigR orthologues and their targets were predicted in 42 actinomycetes. This revealed a conserved core set of SigR targets to function for thiol homeostasis, protein quality control, possible modulation of transcription and translation, flavin-mediated redox reactions, and Fe-S delivery. The composition of the SigR regulon reveals a robust conserved physiological mechanism to deal with thiol-oxidative stress from bacteria to human.