Antitumor activity of C-phycocyanin from Arthronema africanum (Cyanophyceae)

Pure C-phycocyanin (C-PC) was isolated from Arthronema africanum to evaluate its potential antitumor effects in vivo and in vitro. Experimental myeloid Graffi tumor in hamsters was used as a model. The cell proliferation assay showed that C-PC treatment, at concentration of 100 µg mL-1 for 24 h, significantly inhibited the growth of Graffi tumor cells (51.4% viability). Agarose gel electrophoresis of the genomic DNA of treated cells displayed time-and concentration-dependent fragmentation pattern, typical for apoptosis. Apoptotic process was related to the increase in cellular manganese and copper/zinc superoxide dismutases and glutathione reductase activities, coupled with a low catalase activity. In vivo C-PC administration (5.0 mg kg-1 body weight) suppressed the tumor transplantability and growth, while the mean survival time of the tumor-bearing hamsters was increased. The results revealed promising antitumor activities of A. africanum C-PC and suggested the potential of this natural biliprotein pigment for future pharmacological and medical applications. The study provided new data on the mechanism of the C-PC induced apoptosis in which the imbalance of antioxidant enzymes that favoured hydrogen peroxide accumulation might play a leading role.

Biological activities of selected polyphenol-rich fruits related to immunity and gastrointestinal health.

Small fruits are a rich source of bioactive substances, including polyphenols, and are therefore suitable raw materials for the production of functional foods. In the current work, we studied the antioxidative properties of six fruits: rosehip, chokeberry, hawthorn, blackcurrant, blueberry and rowanberry via different methods (ORAC, TRAP, HORAC and inhibition of lipid peroxidation). Their effect on the production of reactive oxygen species (ROS) by phagocytes, antimicrobial properties against 11 human pathogens, and mitogenic effect on hamster spleen lymphocytes were also tested. Rosehip extract showed the highest antioxidant activity via ORAC, TRAP and HORAC assays, whereas blueberry extract was the most potent inhibitor of lipid peroxidation. All extracts inhibited ROS production of opsonized zymosan-activated phagocytes, indicating that extracts interfere with the signaling cascade of phagocyte activation upstream to the protein kinase C activation. Chokeberry, blackcurrant and rowanberry extracts revealed strong antimicrobial properties against a broad spectrum of microorganisms and also had the highest mitogenic activity.

Quaternized chitosan-coated nanofibrous materials containing gossypol: preparation by electrospinning, characterization and antiproliferative activity towards HeLa cells.

Nanofibrous polylactide-based materials loaded with a natural polyphenolic compound gossypol (GOS) with antitumor properties were prepared by electrospinning. The nanofibrous materials were coated with a thin film of crosslinked quaternized chitosan (QCh). GOS incorporated in the nanofibrous mats was in the amorphous state. GOS release was diffusion-controlled and its in vitro release profiles depended on the mat composition. The nanofibrous materials exhibited high cytotoxicity towards HeLa tumor cells. Interestingly, it was particularly pronounced in the case of fibrous materials, which contain both QCh and GOS. The observed strong antiproliferative effect of the nanofibrous mats was mainly due to induction of cell apoptosis.

Electrospun nanofibrous mats containing quaternized chitosan and polylactide with in vitro antitumor activity against HeLa cells.

Nanofibrous materials containing the antitumor drug doxorubicin hydrochloride (DOX) were easily prepared using a one-step method by electrospinning of DOX/poly(L-lactide-co-D,L-lactide) (coPLA) and DOX/quaternized chitosan (QCh)/coPLA solutions. The pristine and DOX-containing mats were characterized by ATR-FTIR and X-ray photoelectron spectroscopy (XPS). The release rate of DOX from the prepared fibers increased with the increase in DOX content. The DOX release process was diffusion-controlled. MTT cell viability studies revealed that incorporation of DOX and QCh in the nanofibrous mats led to a significant reduction in the HeLa cells viability. It was found, that the antitumor efficacy of the DOX-containing mats at 6 h was higher than that of the free DOX. SEM, TEM, and fluorescence microscopic observations confirmed that the antitumor effect of QCh-based and DOX-containing fibrous mats was mainly due to induction of apoptosis in the HeLa cells.