Anti-Aging Effect of Chitosan Oligosaccharide on d-Galactose-Induced Subacute Aging in Mice.

Chitosan oligosaccharide (COS), a natural polysaccharide with good antioxidant and anti-inflammatory properties, is the depolymerized product of chitosan possessing various biological activities. The present study was designed to investigate the possible anti-aging effect of COS on the aging model mouse induced by d-galactose (d-gal) and explore the underlying mechanism. In the experiment, 48 male Kunming mice (KM mice) were randomly divided into the normal group, model group, positive group, and low-medium-high dose polysaccharide groups (300, 600, 1200 mg/kg/day). The results showed that COS, by intragastric gavage after subcutaneous injection of d-gal (250 mg/kg/day) into the neck of mice consecutively for eight weeks, gradually recovered the body weight, the activity of daily living, and organ indices of mice, as well as effectively ameliorated the histological deterioration of the liver and kidney in mice triggered by d-gal. To be specific, COS obviously improved the activities of antioxidant enzymes in liver and kidney of KM mice, including catalase (CAT), glutathione peroxidase (GSH-Px), and superoxide dismutase (SOD), as well as decreased malondialdehyde (MDA) levels when compared with those in model group mice. Furthermore, COS not only elevated the diminished levels of serum immunoglobulin G (IgG) and IgM induced by d-gal, but also significantly inhibited the d-gal-caused upregulation of serum alanine aminotransferase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), uric acid (UA) and creatinine (CREA) levels as compared with those of mice in the model group. These results demonstrate that COS has an obvious anti-aging activity in d-gal-induced subacute aging mice, the mechanism of which, to some extent, is associated with enhancing the antioxidant defenses, reducing oxidative stress, and improving the immune function of aging model mice.

Anti-microtubule activity of tubeimoside I and its colchicine binding site of tubulin.

BACKGROUND: Tubeimoside I (TBMS1) was isolated from the tubers of Bolbostemma paniculatum (Maxim.) Franquet. TBMS1 shows potent anti-tumor activity. The present study was conducted to investigate the anti-microtubule role of TBMS1 and its binding site of tubulin. METHODS: Cell growth inhibition was measured by MTT after treatment with TBMS1. Uptake kinetics of TBMS1 by human nasopharyngeal carcinoma CNE-2Z cell line (CNE-2Z) was assayed by HPLC. Microtubule protein (MTP) was prepared from porcine brain through two cycles of polymerization-depolymerization in a high molarity buffer. Inhibition of MTP polymerization induced by TBMS1 was determined by a turbidity measurement and a sedimentation assay; the interactions of TBMS1 with tubulin within CNE-2Z cells were investigated by immunofluorescence microscopy and immunoblotting. TBMS1 was tested for its ability to inhibit binding of known tubulin ligands through competitive binding assay. RESULTS: TBMS1 displayed growth inhibitory activity against CNE-2Z cells with IC(50) value of 16.7 microM for 72 h. HPLC analysis of TBMS1 uptake by CNE-2Z cells displayed the initial slow TBMS1 uptake and then gradually reaching an maximum uptake near 18 h. CNE-2Z cells treated with TBMS1 (25 microM, 3 h) were sufficient to cause the microtubular network disruption. Immunoblot analysis showed that the proportion of cytosolic tubulin of cells treated with TBMS1 increased in a time- and concentration-dependent manner. TBMS1 did not inhibit the binding of vinblastine to tubulin. Colchicine binding to tubulin was inhibited in the presence of TBMS1. CONCLUSIONS: TBMS1 is an anti-microtubule agent, and its binding site of tubulin is the colchicine binding site of tubulin.

[Cell cycle arrest and apoptosis induced by tubeimoside in HeLa cell].

BACKGROUND & OBJECTIVE: Tubeimoside, which is composed of tubeimoside I (79%) and II (21%), was isolated from the tubers of Bolbostemma paniculatum (Maxim) Franquet (Cucurbitaceae), a traditional Chinese medicine, "Tu-Bei-Mu". This study was designed to investigate the anti-tumor mechanism of tubeimoside. METHODS: Growth inhibition was measured by MTT assay. Induction of cell cycle arrest and apoptosis was determined by flow cytometry, fluorescence and electron microscopy, and gel electrophoresis of fragmented DNA. RESULTS: Tubeimoside display strong growth inhibitory effect in a dose- and time-dependant manner against HeLa cells with estimated IC50 values of 20.0, 18.8, and 8.8 mumol/L after 24, 48, and 72 h of treatment with tubeimoside. The flow cytometry profiles revealed that treatment with tubeimoside (5 h; 15, 30, 35 mumol/L) led to a dose-dependant shift from 9.80% up to 21.90%, and 27.00% in percentage of cells with a G2/M-like DNA content. On the other hand, treatment with tubeimoside (12 h, 15, 30, 35 mumol/L) led to a time-dependant shift from 8.20% up to 21.40%, 31.15%, and 34.55%, respectively. Exposure of HeLa cells to 40 mumol/L of tubeimoside induced nuclear shrinkage, chromation condensation and margination against nuclear envelope, subdiploid peak, and DNA fragmentation, characteristic as seen in apoptotic cells. CONCLUSION: Induction of cell cycle arrest and apoptosis may play an important role in the anti-tumor effect of tubeimoside.