Chemical composition and biotechnological properties of a polysaccharide from the peels and antioxidative content from the pulp of Passiflora liguralis fruits.

A new polysaccharide with a high molecular weight (greater than 1 x 106 Da) was extracted and characterized from the peels of Passiflora liguralis (granadilla) fruits. Chemical composition of the biopolymer, performed by using a high pressure anion exchange-pulsed amperometric detector (HPAE-PAD), showed the presence of six different sugar residues: xylose, glucose, galactose, galactosamine, an unknown component, and fucose in the relative ratio of 1:0.5:0.2:0.06:0.05:trace. The optical rotation of this xyloglucan was [alpha](D)(25) degrees C = -186.42 (concentration of 1.4 mg/mL of H(2)O), and the viscosity was dependent on the concentration and pH, showing a maximum value of 1.4 eta at a concentration of 3% in distilled water and a maximum value of 7.0 eta in citrate buffer solution. Thermogravimetric analysis indicated that this biopolymer was very stable at high temperatures, showing a degradation temperature at 280 degrees C. The characterization of the polysaccharide was also investigated by spectroscopic methods (1H NMR and IR) pointing out the complexity of this biopolymer and the presence of sugar residues in alpha-manno, alpha-gluco-galacto, and beta-gluco-galacto configurations. The formation of a biodegradable film using this novel xyloglucan was reported, and the anticytotoxic activity of the polysaccharide was studied in a brine shrimp bioassay. Considerable antioxidant activity (Trolox equivalent antioxidant capacity (TEAC) value of 0.32 microM/mg fresh product) was noted in the lipophilic extracts of Passiflora liguralis fruits, indicating, in this fruit, an alternative source of bioactive compounds.

Biocompatibility studies on biodegradable polyester-based composites of human osteoblasts: a preliminary screening.

A series of biodegradable composites with natural hydroxyapatite, designed for possible use in orthopedics applications, were preliminarily screened for biocompatibility by employing primary cultures of human osteoblasts in a direct contact method. The cells were seeded at low density onto the materials under investigation and allowed to grow for 2 weeks. They then were analyzed for morphology, proliferation, viability, alkaline phosphatase activity (AP), osteocalcin (OC) production, and extracellular matrix mineralization. The results showed that all materials have good biocompatibility. Cell viability tests demonstrated that in all cases the values were comparable to the control, and the addition of hydroxyapatite always resulted in an enhancement of performance with respect to the plain polymer. AP and OC analysis confirmed that all composites allowed the expression of phenotypic markers. Scanning electron microscopy provided direct evidence of intense cell adhesion and proliferation on the tested materials.