International Journal of Molecular Medical Science, 2024, Vol.14, No.6, 342-354 http://medscipublisher.com/index.php/ijmms 344 The monosaccharide composition of LBPs is consistent across different extraction methods, with glucose, galactose, and xylose typically being the dominant sugars. However, variations in the ratio of these monosaccharides have been observed depending on the extraction technique used and the source of the Lycium barbarumfruit. For instance, studies have shown that the uronic acid content and protein content of LBPs vary based on the extraction method, affecting the overall chemical profile of the polysaccharides. The presence of uronic acids, which contribute to the acidic nature of LBPs, has been associated with their enhanced biological activities such as antioxidant and immunomodulatory effects (Zai et al., 2023). This variability highlights the importance of standardizing extraction techniques to produce consistent bioactive compounds for therapeutic use. Moreover, the structural complexity of LBPs includes side chains and branches that influence their function. The composition of LBPs can include a variety of sugar residues such as glucose, galactose, arabinose, and rhamnose, contributing to a highly branched structure (Figure 2). Studies have demonstrated that these structural features, particularly the branching degree, are closely related to the bioactive potential of LBPs. Higher branching often correlates with better antioxidant and immunomodulatory capabilities. For example, LBPs extracted through fractional precipitation methods show higher levels of glucose and arabinose in their fractions, which contribute to their capacity to activate macrophages and enhance immune response (Gong et al., 2018). Therefore, understanding the precise monosaccharide composition and its relation to bioactivity is essential for developing LBPs as functional ingredients in pharmaceuticals and nutraceuticals. Figure 1 The hypothetical structures of Lycium barbarum polysaccharides (LBPs), particularly highlighting arabinogalactan structures (Adapted from Cao et al., 2022) Image caption: The figure presents three structural representations: (A) an arabinogalactan with a backbone of (1→6)-linked β-galactopyranose (Galp), (B) a (1→3)-linked β-Galp backbone, and (C) a complex structure combining (1→3) and (1→6)-linked β-Galp backbones. These structures demonstrate how different LBPs possess varying configurations, with branching points at specific carbon positions (C3 or C6). This figure emphasizes the structural diversity of LBPs, which is closely linked to their biological activities, such as immunomodulation and metabolic regulation (Adapted from Cao et al., 2022) 2.2 Structural features and molecular weight The molecular weight (Mw) of Lycium barbarum polysaccharides (LBPs) is a crucial determinant of their biological activity. LBPs are generally categorized into high and low molecular weight fractions, each with distinct biological roles. Higher molecular weight LBPs tend to possess a more complex structure, including a
RkJQdWJsaXNoZXIy MjQ4ODYzNQ==