In the present study, the preliminary structure and in vitro antitumor activity of three exopolysaccharides (EPSs) from Streptococcus thermophilus CH9 were investigated. Then, three purified fractions of EPS-1a, EPS-2a, and EPS-3a were obtained by chromatography using DEAE-52 cellulose and Sephadex G-100, respectively. The average molecular weight of EPS-1a, EPS-2a, and EPS-3a, were 1.80 × 10⁶, 1.06 × 10⁶ and 1.05 × 10⁶. The monosaccharide composition of EPS-3a was dramatically different from the others. The EPS-1a and EPS-2a were mainly composed of mannose, in a ratio of 69.82% and 57.09%, respectively, while EPS-3a was mainly composed of glucose (63.93%), without mannose. In addition, the surface morphology observed suggested that there were protein particles on the sugar chain of EPS-3a and EPS-3a was a protein-containing polysaccharide. Furthermore, EPS-3a exhibited higher antitumor activity against human liver cancer HepG2 cells in vitro. The antitumor activity of EPS-3a in HepG2 cells was associated with cell apoptosis. HE staining and Hoechst 33342 staining showed that with the treatment of EPS-3a, HepG2 cells had typical morphological changes. Flow cytometry analysis showed that the cell cycle was arrested at G0/G1 phase.

Dandelion (Taraxacum mongolicum Hand.-Mazz.) is a medicinal and edible plant. Dandelion has great development value for its health promoting benefits; additionally, Dandelion grows almost anywhere in the world. In this study, we report the structural characteristics and anti-cancer activity of novel dandelion leaf polysaccharides extracted by pressurized hot water extraction at 120 °C (DLP120) with Mw relative to dextran of 1.64 × 10⁶ Da. Structural analysis indicated that DLP120 is a complex polysaccharide composed of pectin and arabinogalactan. It was mainly composed of arabinose (32.35 mol%) and galactose (44.91 mol%). The main glycosidic linkages of DLP120 were 4-β-D-Galp, 4-α-D-GalpA, T-β-D-Galp, 5-α-L-Araf, 3,5-α-L-Araf, and T-α-L-Araf. In vitro, DLP120 inhibited HepG2 cell proliferation in a dose-dependent manner by inducing cell apoptosis. Cell cycle detection results revealed that DLP120 mainly arrests the cell cycle in S phase. Cells treated with DLP120 displayed obvious apoptotic morphology, including cell volume shrinks and cytoskeleton breaks down. In short, DLP120 has potential as an anti-cancer agent.

Steam explosion pretreatment was conducted on seabuckthom pomace. Response surface methodology was used to optimize the treatment conditions of steam explosion, including steam pressure, duration and particle size. After this, the content of total flavonoids and the antioxidant capacity of total flavonoids were investigated. Results showed that when the steam pressure was 2.0 MPa, duration was 88 s and a sieving mesh size was 60, the total flavonoids content in seabuckthorm reached a maximum of 24.74 ± 0.71 mg CAE/g, an increase of 246% compared with that without steam explosion treatment (7.14 ± 0.42 mg CAE/g). Also, DPPH and ·OH free radical scavenging ability showed significant improvement, with an IC₅₀ decrease to 13.53 μg/mL and 4.32 μg/mL, respectively, far lower than that in original samples. Through the scanning electron microscope, the surface of seabuckthom pomace after steam explosion was crinkled, curly, and holey. Our study showed that the content of total flavonoids in seabuckthom pomace could be obviously promoted and the antioxidant capacity of total flavonoids also improved significantly, after applying steam explosion pretreatment to seabuckthom pomace, making this approach meaningful for the reuse of seabuckthom pomace resources.

This study aimed to isolate polysaccharides from Penthorum chinense Pursh and evaluate their rheological characteristics, physicochemical properties, and antioxidant activity. The optimal conditions for the maximal extraction yield of Penthorum chinense Pursh polysaccharides (4.05 ± 0.12%) were determined by employing a single-factor test and response surface methodology which included an extraction time of 3 h, a liquid–solid ratio of 20 mL/g, and three separate extraction times. The rheological experiments showcased that the P. chinense polysaccharides exhibited typical shear-thinning behavior, with their apparent viscosity being influenced by various parameters such as concentration, pH, temperature, salt content, and freeze–thaw. The purified polysaccharides (PCP-100), having an average molecular weight of 1.46 × 10⁶ Da, mainly consisted of glucose (18.99%), arabinose (22.87%), galactose (26.72%), and galacturonic acid (21.89%). Furthermore, the PCP-100 exhibited high thermal stability and displayed an irregular sheet-like morphology. Its superior reducing power and free radical scavenging ability implied its significant antioxidant activity in vitro. Collectively, these findings provide important insights for the future application of P. chinense polysaccharides in the food industry.

Dandelion is an edible plant with a variety of bioactive components. This paper mainly reports the antitumor activity of dandelion polysaccharide DLP120 on H22 tumor-bearing mice. DLP120 is an acidic polysaccharide composed of pectin and arabinogalactan. The results indicate that DLP120 markedly inhibited tumor growth in a dose-dependent manner and attenuated and regulated negative effects on organs. In addition, DLP120 not only increased the viability of spleen lymphocytes and natural killer (NK) cells, but also increased the proportion of lymphocyte subsets in peripheral blood. Furthermore, Hematoxylin-Eosin (HE) staining showed that tumor tissues and cells exhibited typical pathology features. Annexin V FITC/PI staining and cell cycle distribution results further confirmed apoptosis and cell cycle arrest in S and G2 phases. Notably, there was a significant accumulation of reactive oxygen species. Western blotting results demonstrated that the expression of p53 was up-regulated in the DLP120 group. Moreover, the pro-apoptotic protein Bax was up-regulated while the inhibitory-apoptotic protein Bcl-2 was down-regulated. In addition, the expression of Fas and FasL, associated with the death receptor pathway, were also up-regulated. Overall, administration of DLP120 in H22 tumor-bearing mice can not only enhance immunity but also directly induce tumor cell apoptosis.