School of Life Science, Jawaharlal Nehru University, New Delhi, 110067, India.
School of Life Science, Jawaharlal Nehru University, New Delhi, 110067, India.
Carbohydr Polym. 2019 Mar 1;207:460-470. doi: 10.1016/j.carbpol.2018.12.003. Epub 2018 Dec 6.
Present study was designed to investigate the role of acemannan acetyl group in murine radioprotection. Acemannan, extracted from Aloe vera gel, has molecular weight of 1.02 × 10 Da and mainly composed of mannose (84.9%), glucose (7.2%), and galactose (3.9%), with backbone of (1→4)-linked mannose and glucose. Acemannan was over-acetylated and deacetylated to investigate the role of acetyl group. Acetylation enhances acemannan viscosity and thermal stability. Free radicals scavenging and Fenton reaction inhibition was mediated by acemannan acetyl and hydroxyl group respectively. Native or over-acetylated or deacetylated acemannan pre-treatment to mice has shown to reduce the γ-radiation-induced oxidative damage, and hematopoietic injuries by free radical scavenging and microphage activation (secretes pro-hematopoietic factors through TLR-4) respectively. Over-acetylated acemannan has stronger effects on immunomodulation/radioprotection. In summary, acemannan acetyl-group modulates immune system, while hydroxyl-group participate in free radical scavenging, and present finding can be employed in food and pharma industries for enhancing polysaccharide bioactivity.
本研究旨在探讨乙酰基在槲皮素乙酰化修饰对小鼠放射防护作用中的影响。槲皮素，从芦荟凝胶中提取，分子量为 1.02 × 10 Da，主要由甘露糖（84.9%）、葡萄糖（7.2%）和半乳糖（3.9%）组成，其骨干为（1→4）连接的甘露糖和葡萄糖。通过对槲皮素进行乙酰化修饰和脱乙酰化修饰，来研究乙酰基的作用。乙酰化修饰可以提高槲皮素的粘度和热稳定性。自由基清除和芬顿反应抑制分别由槲皮素乙酰基和羟基基团介导。对小鼠进行天然、乙酰化或脱乙酰化的槲皮素预处理，通过自由基清除和巨噬细胞激活（通过 TLR-4 分泌促造血因子），分别减少了γ射线诱导的氧化损伤和造血损伤。乙酰化修饰的槲皮素对免疫调节/放射防护的作用更强。总之，槲皮素乙酰基调节免疫系统，而羟基基团参与自由基清除，这一发现可用于食品和制药行业，以提高多糖的生物活性。
