Some new insights into the biological activities of carboxymethylated polysaccharides from Lasiodiplodia theobromae

Background Carboxymethylated Lasiodiplodan (LaEPS-C), Lasiodiplodia theobromae [beta]-glucan exopolysaccharide derivative, has a well-known range of biological activities. Compared to LaEPS-C, its fractions, Linear (LLaEPS-C) and Branched (BLaEPS-C), have biological potentialities scarcely described in the literature. So, in this study, we investigate the immunomodulatory, antiviral, antiproliferative, and anticoagulant activities of LLaEPS-C and BLaEPS-C and compare them to the LaEPS-C. Methods LaEPS was obtained from L. theobromae MMBJ. After carboxymethylation, LaEPS-C structural characteristics were confirmed by Elementary Composition Analysis by Energy Dispersive X-Ray Detector (EDS), Fourier Transform Infrared (FTIR), and Nuclear Magnetic Resonance (NMR). The immunomodulatory activity on cytokine secretion was evaluated in human monocyte-derived macrophage cultures. The antiviral activity was evaluated by Hep-2 cell viability in the presence or absence of hRSV (human respiratory syncytial virus). In vitro antiproliferative activity was tested by sulforhodamine B assay. The anticoagulant activity was determined by APTT (Activated Partial Thromboplastin Time) and PT (Prothrombin Time). Results LaEPS-C showed low macrophage cell viability only at 100 [micro]g/mL (52.84 [+ or -] 24.06, 48 h), and LLaEPS-C presented no effect. Conversely, BLaEPS-C showed cytotoxicity from 25 to 100 [micro]g/mL (44.36 [+ or -] 20.16, 40.64 [+ or -] 25.55, 33.87 [+ or -] 25.16; 48 h). LaEPS-C and LLaEPS-C showed anti-inflammatory activity. LaEPS-C presented this at 100 [micro]g/mL (36.75 [+ or -] 5.53, 48 h) for IL-10, and LLaEPS-C reduces TNF-[alpha] cytokine productions at 100 [micro]g/mL (18.27 [+ or -] 5.80, 48 h). LLaEPS-C showed an anti-hRSV activity (0.7 [micro]g/ml) plus a low cytotoxic activity for Hep-2 cells (1.4 [micro]g/ml). LaEPS-C presented an antiproliferative activity for NCI-ADR/RES (GI.sub.50 65.3 [micro]g/mL). A better PT was achieved for LLaEPS-C at 5.0 [micro]g/mL (11.85 [+ or -] 0.87s). Conclusions These findings demonstrated that carboxymethylation effectively improves the biological potential of the LaEPS-C and their fractions. From those polysaccharides tested, LLaEPS provided the best results with low toxicity for anti-inflammatory, antiviral, and anticoagulant activities. Keywords: Lasiodiplodan, Immunomodulatory and Antiviral, Antiproliferative, Anticoagulant activities