Cytotoxicity activities and chemical characteristics of exopolysaccharides and intracellular polysaccharides of Physarum polycephalum microplasmodia

Abstract

Background Microbial polysaccharides have been reported to possess remarkable bioactivities. Physarum polycephalum is a species of slime mold for which the microplasmodia are capable of rapid growth and can produce a significant amount of cell wall-less biomass. There has been a limited understanding of the polysaccharides produced by microplasmodia of slime molds, including P. polycephalum. Thus, the primary objectives of this research were first to chemically characterize the exopolysaccharides (EPS) and intracellular polysaccharides (IPS) of P. polycephalum microplasmodia and then to evaluate their cytotoxicity against several cancer cell lines. Results The yields of the crude EPS (4.43 ± 0.44 g/l) and partially purified (deproteinated) EPS (2.95 ± 0.85 g/l) were comparable (p > 0.05) with the respective crude IPS (3.46 ± 0.36 g/l) and partially purified IPS (2.45 ± 0.36 g/l). The average molecular weight of the EPS and IPS were 14,762 kDa and 1788 kDa. The major monomer of the EPS was galactose (80.22%), while that of the IPS was glucose (84.46%). Both crude and purified IPS samples showed significantly higher cytotoxicity toward Hela cells, especially the purified sample and none of the IPSs inhibited normal cells. Only 38.42 ± 2.84% Hela cells remained viable when treated with the partially purified IPS (1 mg/ml). However, although only 34.76 ± 6.58% MCF-7 cells were viable when exposed to the crude IPS, but the partially purified IPS displayed non-toxicity to MCF-7 cells. This suggested that the cytotoxicity toward MCF-7 would come from some component associated with the crude IPS sample (e.g. proteins, peptides or ion metals) and the purification process would have either completely removed or reduced amount of that component. Cell cycle analysis by flow cytometry suggested that the mechanism of the toxicity of the crude IPS toward MCF-7 and the partially purified IPS toward Hela cells was due to apoptosis. Conclusions The EPS and IPS of P. polycephalum microplasmodia had different chemical properties including carbohydrate, protein and total sulfate group contents, monosaccharide composition and molecular weights, which led to different cytotoxicity activities. The crude and partially purified IPSs would be potential materials for further study relating to cancer treatment.

Polysaccharides from fungi: A review on their extraction, purification, structural features, and biological activities

“…Notably, the crude extracellular polysaccharides can be directly extracted from fungal fermentation medium by ethanol precipitation methods ( Miao et al, 2020 , Zhao et al, 2015 ). As for intracellular fungal polysaccharides, they are mainly from fruiting bodies or mycelium of fungi by different extraction methods ( Ba et al, 2020 , Do et al, 2021 , Moradi and Kalanpour, 2019 , Zhang et al, 2020a ). Before extracting intracellular fungal polysaccharides, raw materials undergo a series of pretreatment, including washing, drying, crushing, and degreasing.…”

Unveiling the Structural Characteristics and Bioactivities of the Polysaccharides Extracted from Endophytic Penicillium sp.

“…is reported to induce MDA-MB cells death via apoptosis and necrosis [16]. Similarly, flow cytometric analysis of a previous study reported that fungi-derived IPS fraction induces apoptosis in human breast cancer (MCF-7) and cervical cancer (Hela) cells at 1000 µg/mL of the treatment dose [13]. Taken together, the findings of cytotoxicity analysis in PC-3 cells (Figures 8 and 9) indicated that the IPS-1 could induce apoptosis in PC-3 cells via nuclear damage associated with mitochondrial membrane potential collapse.…”

“…However, the chemical shifts of the IPS-2 signals were mainly distributed in δ 3.6-4.1 and δ 5.0-5.3 (anomeric proton region) (Figure 4b). In the 13 C-NMR spectrum, the IPS-1 signals (ppm) were found at 99.82 (C1), 81.36 (C3), 74.13 (C5), 71.76 (C2), 70.38 (C4), 60.58 (C6) (Figure 4c). Similarly, the IPS-2 signals (ppm) were distributed at 102 (C1), 82.61 (C3), 76.4 (C5), 72.79 (C2), 70.34 (C4), 61.09 (C6) (Figure 4d).…”

“…Conceivably, the polysaccharides with lower molecular weights contain reductive hydroxyl group terminals (per unit mass), enabling free radical acceptance and elimination [12]. On the other hand, polysaccharides with higher molecular weights are thought to exhibit stronger connections with receptors/proteins on cancer cells that perhaps exert enhanced anticancer effects [13]. Yet, several studies have reported that the polysaccharides derived from natural sources could behave as antioxidant and anticancer agents [14][15][16].…”

Polyethylenimine-Conjugated Hydroxyethyl Cellulose for Doxorubicin/Bcl-2 siRNA Co-Delivery Systems

“…Contrary to HeLa cells, free Dox-treated HepG2 cells demonstrated above 60% cell viability even at a high concentration (15 μg/mL) ( Figure S7B and Figure 8 B). Several studies have reported that HepG2 cells are less sensitive to Dox than HeLa cells [ 37 , 38 ]. Except for free siRNA, the viability of other samples-treated cells decreased as the concentration increased, showing their cancer cell-killing effect.…”