Galactan is a major sulfate polysaccharide in the red seaweed, Pyropia yezoensis. In the present study, the prebiotic potential and anticancer activities of three sulfate galactans with different molecular weights (GPY_crude, GPY₃₀₀, and GPY₁₀) were evaluated in vitro. Monosaccharide composition and structural analyses of these sulfate galactans showed that all polysaccharide fractions contained the same monosaccharides but had different molecular weights. All the polysaccharides tested displayed potential prebiotic activity, with GPY₁₀ noticeably having the best potential compared to others, especially for Bifidobacterium spp., which highlights possible correlations between structural galactan features and prebiotic activity. Furthermore, all three sulfate galactans were cytotoxic to DU145 and PC-3 prostate cancer cells, with GPY₁₀ exhibiting the greatest inhibition in DU145 cells. Moreover, GPY₁₀ induced modulates the production of intracellular reactive oxygen species (ROS), with subsequent increased apoptosis of DU145 prostate cancer cell and modulating the PI3K/AKT/mTOR signaling pathway. GPY₁₀ increased expression of Bax, executor caspase-3, and initiator caspases 8 and 9. Therefore, sulfate galactans from P. yezoensis could be applied as a novel prebiotic and anticancer compounds in prostate cancer cells.

半乳聚糖是红海藻（Pyropia yezoensis）中的主要硫酸盐多糖。在本研究中，在体外评估了三种分子量不同的硫酸盐半乳聚糖（GPY_原油，GPY ₃₀₀和GPY ₁₀）的益生元潜力和抗癌活性。这些硫酸半乳聚糖的单糖组成和结构分析表明，所有多糖级分均包含相同的单糖，但分子量不同。所有测试的多糖均显示出潜在的益生元活性，与其他多糖相比，GPY ₁₀具有最大的潜力，尤其是对于双歧杆菌而言spp。，强调了结构半乳聚糖特征与益生元活性之间的可能关联。此外，所有三种硫酸半乳聚糖均对DU145和PC-3前列腺癌细胞具有细胞毒性，其中GPY ₁₀在DU145细胞中表现出最大的抑制作用。此外，GPY ₁₀诱导调节细胞内活性氧（ROS）的产生，随后增加DU145前列腺癌细胞的凋亡并调节PI3K / AKT / mTOR信号通路。GPY ₁₀可增加Bax，执行子caspase-3和启动子半胱氨酸蛋白酶8和9的表达。因此，来自耶氏疟原虫的硫酸半乳聚糖可用作前列腺癌细胞中的新型益生元和抗癌化合物。