Preparation of alginate/chitosan microcapsules and enteric coated granules of mistletoe lectin

Abstract

The aqueous extract of European mistletoe (Viscum album, L.) has been used in cancer therapy. The purified mistletoe lectins, main components of mistletoe, have demonstrated cytotoxic and immune-system-stimulating activities. Korean mistletoe (Viscum album L. coloratum), a subspecies of European mistletoe, has also been reported to possess anticancer and immunological activities. A galactose- and N-acetyl-D-galactosamine-specific lectin (Viscum album L. coloratum agglutinin, VCA) with Mr 60 kDa was isolated from Korean mistletoe. Mistletoe preparations have been given subcutaneously due to the low stability of lectin in the gastrointestinal (GI) tract. In the present study, we investigated the possibility of alginate/chitosan microcapsules as a tool for oral delivery of mistletoe lectin. In addition, our strategy has been to develop a system composed of stabilizing cores (granules), which contain mistletoe lectin, extract or powder, coated by a biodegradable polymer wall. Our results indicated that successful incorporation of VCA into alginate/chitosan microcapsules has been achieved and that the alginate/chitosan microcapsule protected the VCA from degradation at acidic pH values. And coating the VCA with polyacrylic polymers, Eudragit, produced outstanding results with ideal release profiles and only minimal losses of cytotoxicity after manufacturing step. The granules prepared with extract or whole plant produced the best results due to the stability in the extract or whole plant during manufacturing process.

Preparation of phycocyanin microcapsules and its properties

“…There were evident effects of alginate content on the encapsulation efficiency, phycocyanin load and shape of phycocyanin microcapsules. Both encapsulation efficiency and phycocyanin load were increased with alginate content increased ranging from 1.0% to 3.5%, different from the results reported by others (Lyu et al, 2004;Meng and Chen, 2010). Microcapsule shape could be affected by the viscosity of the alginate solution, and higher viscosity would bring difficulty in extrusion process and easily result in tailing.…”

“…Content of calcium chloride had no significant effect on the encapsulation efficiency and phycocyanin load of microcapsules, as shown in Table 1, different from the conclusion obtained by Lyu et al (2004), Vandenberg et al (2001) and Gao et al (2009). Its reason was possibly that high-molecularweight phycocyanin could not exude from the alginate gel (Yoo et al, 2006) formed even at lower content of calcium chloride.…”

Anti-cancer effects of enteric-coated polymers containing mistletoe lectin in murine melanoma cells in vitro and in vivo

“…In our previous study, we developed a system composed of stabilizing cores (granules) which contained VCA, coated with a biodegradable polymer (Eudragit Ò ) wall. This system produced outstanding results with ideal release profiles and only minimal losses of cytotoxicity in human hepatocarcinoma cells after the manufacturing step [16]. We also studied the transport mechanism of VCA by M cells in human follicle-associated epithelium (FAE) in vitro [30], and the modulation of cytokines and immunoglobulin (Ig) A in intestinal epithelial cells (IEC) [31].…”

“…In this study, we evaluated the effects of enteric-coated mistletoe we have previously developed [16] on the growth of mouse melanoma cells in vitro and in vivo.…”

“…A galactose-and N-acetyl-Dgalactosamine-specific lectin (Viscum album L. var. coloratum agglutinin, VCA) was isolated from Korean mistletoe [8] which is composed of two different subunits; the A-chain which inactivates the 60S ribosomal subunit in eukaryotic cells resulting in the inhibition of protein synthesis, and the B-chain which binds to the cell-surface glycoconjugates and thereby permits entry into the cell of the toxic A-chain subunit [7,[14][15][16].…”