DataSheet1_The structural characterization and UV-protective properties of an exopolysaccharide from a Paenibacillus isolate.docx

IntroductionOverexposure to ultraviolet (UV) light is known to cause damage to the skin, leading to sunburn and photo-aging. Chemical sunscreen products may give rise to health risks including phototoxicity, photosensitivity, and photosensitivity. Natural polysaccharides have attracted considerable interests due to diverse biological activities.
MethodsA novel polysaccharide isolated was purified and structurally characterized using chemical methods followed by HPLC, GLC-MS, as well as 1D and 2D NMR spectroscopy. The photoprotective effect of the EPS on UVB-induced damage was assessed in vitro using cultured keratinocytes and in vivo using C57BL/6 mouse models.
ResultsThe average molecular weight of the EPS was 5.48 × 106 Da, composed of glucose, mannose and galactose residues at a ratio of 2:2:1. The repeating units of the EPS were →3)-β-D-Glcp (1→3) [β-D-Galp (1→2)-α-D-Glcp (1→2)]-α-D-Manp (1→3)-α-D-Manp (1→. In cultured keratinocytes, the EPS reduced cytotoxicity and excessive ROS production induced by UVB irradiation. The EPS also exhibits an inhibitory effect on oxidative stress, inflammation, and collagen degradation found in the photodamage in mice. 1H NMR-based metabolomics analysis for skin suggested that the EPS partly reversed the shifts of metabolic profiles of the skin in UVB-exposed mice.
ConclusionThe EPS exhibits skin photoprotective effects through regulating oxidative stress both in vivo and in vitro. Our findings highlight that the EPS is a potential candidate in sunscreen formulations for an efficient solution to UVB radiation.

引言：过度暴露于紫外线（UV）会损伤皮肤，引发晒伤与光老化。化学防晒产品可能带来包括光毒性、光敏性及光敏性在内的健康风险。天然多糖（natural polysaccharides）因具备多样的生物活性而受到广泛关注。
方法：本研究纯化得到一种新型多糖，并通过化学方法结合高效液相色谱（HPLC）、气相色谱-质谱联用（GLC-MS）以及一维和二维核磁共振（NMR）光谱对其结构进行表征。随后，本研究利用体外培养的角质形成细胞与体内C57BL/6小鼠模型，评估了该胞外多糖（exopolysaccharide, EPS）对UVB诱导皮肤损伤的光保护效果。
结果：该胞外多糖（EPS）的平均分子量为5.48×10⁶ Da，由葡萄糖、甘露糖与半乳糖残基以2:2:1的摩尔比组成。其重复单元为→3)-β-D-Glcp (1→3) [β-D-Galp (1→2)-α-D-Glcp (1→2)]-α-D-Manp (1→3)-α-D-Manp (1→。在体外培养的角质形成细胞中，该EPS可降低UVB照射诱导的细胞毒性与过量活性氧（reactive oxygen species, ROS）生成。该EPS还可抑制小鼠光损伤模型中出现的氧化应激、炎症反应与胶原蛋白降解。基于氢核磁共振（¹H NMR）的皮肤代谢组学分析显示，该EPS可部分逆转UVB暴露小鼠的皮肤代谢谱偏移。
结论：该胞外多糖（EPS）可通过在体内外调控氧化应激发挥皮肤光保护作用。本研究结果表明，该EPS可作为防晒制剂的潜在候选成分，为UVB辐射防护提供高效解决方案。