As an edible algae with rich nutrients and high medicinal value, Durvillaea antarctica has certain potential in anti-aging, but there is currently limited research on the separation, purification and activity of its anti-aging active ingredients. We successfully extracted and purified a new β-(1,3)-D-glucan with a special branched structure from Durvillaea antarctica using subcritical water extraction combined with ultrafiltration membrane (SWE-UFM). The polysaccharide, named DAG-1, consists of glucose (92.70%) and has a weight-average molecular weight of 10149 Da. The GC–MS and 1D/2D NMR confirmed that DAG-1 was composed of 3)-β-D-Glcp-(1 → , → 3,6)-β-D-Glcp-(1 → , β-D-Glcp-(1 → and → 6)-α-D-Glcp-(1 → , and β-glycosidic linkages between these sugar units. Animal experiments showed that DAG-1 has significant anti-skin aging effects by inhibiting the reduction of superoxide dismutase (SOD) activity, accumulation of malonic dialdehyde (MDA), and decline in hydroxyproline (HYP) content in collagen fibers of D-gal-induced mouse skin. To further elucidate the mechanism of DAG-1, we found that DAG-1 can alleviate senescence in human dermal fibroblasts (HDFa), inhibit degranulation of human cutaneous mast cells (HCMC), and modulate inflammatory factors (TNF-α, IL-6) production. Additionally, DAG-1 may bind to c-KIT receptors and downregulate the expression of KITLG/KIT, regulating the growth and activation of mast cells, and thus alleviate skin aging. These findings suggest that DAG-1 is a potential anti-aging ingredient for functional food, cosmetic, and medicine development.
Yong-Jian Xiong,Da-Peng Chen,Bo-Chao Lv,Fang-Fei Liu,Li Wang,Yuan Lin
Nobiletin , a citrus polymethoxylated flavone , exhibits multiple biological properties including anti-inflammatory, anti-carcinogenic, and anti-insulin resistance effects. The present study found that nobiletin exerted significant stimulatory effects on the contractility of isolated rat jejunal segments in all 6 different low contractile states, and meanwhile significant inhibitory effects in all 6 different high contractile states, showing characteristics of bidirectional regulation (BR). Nobiletin-exerted BR on jejunal contractility was abolished in the presence of c-kit receptor tyrosine kinase inhibitor imatinib or Ca 2 + channel blocker verapamil . In the presence of neuroxin tetrodotoxin , nobiletin only exerted stimulatory effects on jejunal contractility in both low and high contractile states. Hemicholinium-3 and atropine partially blocked nobiletin-exerted stimulatory effects on jejunal contractility in low-Ca 2 + -induced low contractile state. Phentolamine or propranolol or l -NG-nitro-arginine significantly blocked nobiletin-exerted inhibitory effects on jejunal contractility in high-Ca 2 + -induced high contractile state respectively. The effects of nobiletin on myosin light chain kinase (MLCK) mRNA expression, MLCK protein content, and myosin light chain phosphorylation extent were also bidirectional. In summary, nobiletin-exerted BR depends on the contractile states of rat jejunal segments. Nobiletin-exerted BR requires the enteric nervous system, interstitial cell of Cajal, Ca 2 + , and myosin phosphorylation-related mechanisms.
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