Stimulating effects of Bacillus subtilis natto-fermented Radix astragali on hyaluronic acid production in human skin cells.
BACKGROUND
Radix astragali, a well-known Chinese herb, which has been traditionally used for skincare, and microbial fermentation is one of the conventional methods for processing Chinese herbs.


OBJECTIVE
This research studied the effects of non-fermented (HQNB) and fermented preparations (HQB) of Radix astragali on hyaluronic acid (HA) production in primary human skin cells.


METHODS
HQB and HQNB were prepared and added to the cultures of primary human skin cells. Hyaluronic acid content was determined using ELISA. Real-time RT-PCR was used to evaluate hyaluronan synthase gene expression. The bioactive compounds were analyzed by HPLC.


RESULTS
The growth-stimulating effect of HQNB on both of keratinocytes and fibroblasts were significantly higher than that of HQB. Conversely, HQB, but not HQNB significantly stimulated HA production in both cultured primary human epidermal keratinocytes and human dermal fibroblasts in dose-dependent manners. In addition, HQB markedly and dose-dependently increased the expression of hyaluronan synthase 3 and hyaluronan synthase 2 mRNA in HaCaT cells and human fibroblasts, respectively. Therefore, HQB might be a promising candidate for preventing the age-dependent loss of HA content in aged human skin, and its effect on the enhancement of HA synthesis in skin cells is highly related to its effect on the expression of hyaluronan synthase genes. The three major active isoflavonoids in Radix astragali were identified as ononin, calycosin, and formononetin. After fermentation, all of these three compounds in HQB were significantly reduced. However, HQB still had significantly higher enhancement effect on the production of HA than HQNB. It appeared that isoflavonoid aglycones or other metabolites, converted from their primary isoflavones during fermentation, might be responsible for the skincare functions found in this study.


CONCLUSIONS
This study demonstrated the low toxicity and the stimulating effects of HQB on HA synthesis, and suggests that HQB may play a promising role in anti-aging cosmetic applications.
Hsu
Mei-Fang
MF
Institute of Food Science and Technology, National Taiwan University, P.O. Box 23-14, Taipei, Taiwan, ROC.
Chiang
Been-Huang
BH
D027883:Astragalus Plant / Q000235:genetics / Q000378:metabolism*; D001412:Bacillus subtilis / Q000378:metabolism; D002478:Cells, Cultured; D020405:Dermis / Q000166:cytology / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism; D005285:Fermentation; D005347:Fibroblasts / Q000737:chemistry / Q000378:metabolism*; D015870:Gene Expression; D014453:Glucuronosyltransferase / Q000378:metabolism; D006801:Humans; D000076002:Hyaluronan Synthases; D006820:Hyaluronic Acid / Q000096:biosynthesis*; D015603:Keratinocytes / Q000737:chemistry / Q000378:metabolism*; D018517:Plant Roots / Q000378:metabolism*; D012867:Skin / Q000166:cytology* / Q000378:metabolism; D045730:Soy Foods / Q000382:microbiology
D006820:Hyaluronic Acid; D014453:Glucuronosyltransferase; D000076002:Hyaluronan Synthases