Anne Berit Samuelsen

The traditional uses, chemical constituents and biological activities of Plantago major L. A review

Abstract Plantago major L. leaves have been used as a wound healing remedy for centuries in almost all parts of the world and in the treatment of a number of diseases apart from wound healing. These include diseases related to the skin, respiratory organs, digestive organs, reproduction, the circulation, against cancer, for pain relief and against infections. P. major contains biologically active compounds such as polysaccharides, lipids, caffeic acid derivatives, flavonoids, iridoid glycosides and terpenoids. Alkaloids and some organic acids have also been detected. A range of biological activities has been found from plant extracts including wound healing activity, anti-inflammatory, analgesic, antioxidant, weak antibiotic, immuno modulating and antiulcerogenic activity. Some of these effects may attribute to the use of this plant in folk medicine.

Interaction Between Human Complement and a Pectin Type Polysaccharide Fraction, PMII, from the Leaves of Plantago major L.

The interaction between a pectin type polysaccharide fraction, PMII, isolated from the leaves of Plantago major, and human complement was tested in two different hemolytic complement‐fixation tests and in addition by two elisa methods detecting complement‐activation products. Sera were used as a complement source of 10 arbitrary human volunteers, individually and as a pool. The complement‐fixation tests were designed to measure the concentration of the pectin necessary to inhibit 50% of the hemolysis (ICH50). The elisa tests for complement‐activation products were measured in AU/mg using a fully activated serum as a standard. We observed a more than 200‐fold difference in ICH50 activity of the PMII pectin in one of the hemolytic tests by varying the individual sera used as complement‐source. On the other hand, the elisa complement‐activation tests showed no significant variation in activity of the PMII depending on the complement‐serum used. The level of antibodies against PMII detected in the complement‐sera did not correlate with the ICH50 activity of PMII. The results show that PMII is a potent complement activator with an activity of the same order of magnitude on a weight basis as that of aggregated human immunoglobulin (Ig)G. This activation leads to a complement consumption probably explaining the PMIIs effect in the complement‐fixation tests. PMII seems to be an activator both on the classical and the alternative pathway of activation. The results might be related to the reported wound‐healing effect of the leaves of Plantago major.

Characterization of a biologically active pectin from Plantago major L.

Abstract PMII isolated from the leaves of Plantago major L. is a pectin type polysaccharide with anti-complementary activity. It is highly esterified and partly O-acetylated with regions of 1,4 linked polygalacturonic acid and at least two different hairy regions. The galactose side chains are linked to position 4 of rhamnose in the main chain. The structure of the galactan side chains is complex, but 1,3,6 linkages are dominating in one of the isolated hairy regions. Arabinose is attached to position 3 and 6 of galactose. In the other hairy region arabinose is attached to position 3 of galacturonic acid. De-esterification and de-acetylation do not alter the anti-complementary activity of PMII. Different parts of PMII were shown to have different activities. The smooth regions are only slightly active in contrast to the hairy regions which had significantly higher activity. The hairy regions of highest molecular weight (PVa) with 1,3,6 linked galactose side chains were found to be the most active fraction. The importance of arabinose for the activity seems to depend on the site of substitution. Removal of arabinose terminally linked to galactose increases the activity slightly while removal of arabinose linked to the galacturonic acid backbone decreases the activity.

Structural features and anti-complementary activity of some heteroxylan polysaccharide fractions from the seeds of Plantago major L.

Polysaccharides were isolated from the seeds of Plantago major L. by water extraction and fractionated by ion exchange and size exclusion chromatography. Methods such as methanolysis and GC, methylation analysis and GC-MS, weak acid hydrolysis, enzyme hydrolysis, 13C, APT, 1H and 2D heteronuclear (1H–13C) chemical shift correlated NMR spectroscopy have revealed that the polysaccharides isolated are heteroxylans which consist of a 1,4-linked (β-D-Xylp backbone with short side chains attached to position 2 in some 1,4-linked β-D-Xylp residues and to position 3 in other 1,4-linked β-D-Xylp residues. The side chains consist of β-D-Xylp, α-L-Araf, α-L-Araf 1→3 β-D-Xylp and α-D-Glcp A1→3 α-L-Araf.1,4-linked α-D-GalpA residues were also detected in addition to small amounts of 1,2,4-linked Rhap and 1,3- 1,6- and 1,3,6-linked Galp. The crude extract and some of the fractions obtained had potent anti-complementary activity.

Characterization of a biologically active arabinogalactan from the leaves of Plantago major L.

Abstract PMIa is a Type II arabinogalactan with anti-complementary activity isolated from the leaves of Plantago major L. It has a molecular weight of 77000–80000 Da and consists of arabinose (38%), galactose (49%), rhamnose (6%), galacturonic acid (7%) and 1.5% protein with hydroxyproline, alanine and serine as the main amino acids. Characterization of PMIa by methylation and GC-MS, methanolysis and GC, Smith degradation, weak acid hydrolysis, 13C-NMR, 1H-NMR, two-dimensional heteronuclear NMR and DEPT show that it consists of 1,3-linked galactan chains with 1,6-linked galactan side chains attached to position 6. The side chains are further branched in position 3 with 1,3-linked galactose residues which have 1,6-linked galactose attached to position 6; these 1,3- and 1,6-linked galactose chains altogether probably form a network. Terminal and 1,5-linked arabinose in furanose form are attached to the galactan mainly through position 3 of the 1,6-linked galactose side chains.

The potential of pectin as a stabilizer for liposomal drug delivery systems

The aim of the present study was to investigate the potential of different types of pectin as stabilizers for liposomal drug delivery systems. Positively charged liposomes were coated with commercially available and purified low-methoxylated (LM), high-methoxylated (HM) and amidated (AM) pectins. The samples were stored for up to 12 weeks at 4°C, at room temperature and at 35°C. The change in liposomal size and size distribution, zeta potential, pH, leakage of encapsulated carboxyfluorescein (CF), and lipid degradation were studied. All the types of pectin were found to protect the liposomes against aggregation during storage. The pectin coat did not affect the permeability of the liposome membrane. HM and LM pectin seemed to be the most promising types of pectin due to minimal changes in the zeta potentials during storage for these samples and no detectable lipid degradation. It is concluded that pectin may be used for stabilizing liposomal drug delivery systems.

Protective Effect of Plantago major L. Pectin Polysaccharide against Systemic Streptococcus pneumoniae Infection in Mice

The antibacterial effect of a soluble pectin polysaccharide, PMII, isolated from the leaves of Plantago major, was examined in inbred NIH/OlaHsd and Fox Chase SCID mice experimentally infected with Streptococcus pneumoniae serotype 6B. Serotype 6B is known to give a more protracted infection when injected intraperitoneally into susceptible mice than more virulent serotypes like type 4. PMII was administered i.p. either once 3 days before challenge or once to thrice from 3 to 48 h after challenge. The number of bacteria in blood and the mouse survival rate were recorded. Pre‐challenge administration of PMII and also lipopolysaccharide (LPS), included as a control, gave a dose‐dependent protective effect against S. pneumoniae type 6B infection. However, injection of PMII after establishment of the infection in NIH/OlaHsd mice had no effect. The data demonstrate that, firstly, the polysaccharide fraction PMII from P. major protects against pneumococcal infection in mice when administered systemically prechallenge, and secondly that the protective effect is owing to stimulation of the innate and not the adaptive immune system.

Effects of orally administered yeast-derived beta-glucans: A review

Yeast-derived beta-glucans (Y-BG) are considered immunomodulatory compounds suggested to enhance the defense against infections and exert anticarcinogenic effects. Specific preparations have received Generally Recognized as Safe status and acceptance as novel food ingredients by European Food Safety Authority. In human trials, orally administered Y-BG significantly reduced the incidence of upper respiratory tract infections in individuals susceptible to upper respiratory tract infections, whereas significant differences were not seen in healthy individuals. Increased salivary IgA in healthy individuals, increased IL-10 levels in obese subjects, beneficial changes in immunological parameters in allergic patients, and activated monocytes in cancer patients have been reported following Y-BG intake. The studies were conducted with different doses (7.5-1500 mg/day), using different preparations that vary in their primary structure, molecular weight, and solubility. In animal models, oral Y-BG have reduced the incidence of bacterial infections and levels of stress-induced cytokines and enhanced antineoplastic effects of cytotoxic agents. Protective effects toward drug intoxication and ischemia/reperfusion injury have also been reported. In conclusion, additional studies following good clinical practice principles are needed in which well-defined Y-BG preparations are used and immune markers and disease endpoints are assessed. Since optimal dosing may depend on preparation characteristics, dose-response curves might be assessed to find the optimal dose for a specific preparation.

Immunomodulatory Activity of Dietary Fiber: Arabinoxylan and Mixed-Linked Beta-Glucan Isolated from Barley Show Modest Activities in Vitro

High intake of dietary fiber is claimed to protect against development of colorectal cancer. Barley is a rich source of dietary fiber, and possible immunomodulatory effects of barley polysaccharides might explain a potential protective effect. Dietary fiber was isolated by extraction and enzyme treatment. A mixed-linked β-glucan (WSM-TPX, 96.5% β-glucan, Mw 886 kDa), an arabinoxylan (WUM-BS-LA, 96.4% arabinoxylan, Mw 156 kDa), a mixed-linked β-glucan rich fraction containing 10% arabinoxylan (WSM-TP) and an arabinoxylan rich fraction containing 30% mixed-linked β-glucan (WUM-BS) showed no significant effect on IL-8 secretion and proliferation of two intestinal epithelial cell lines, Caco-2 and HT-29, and had no significant effect on the NF-κB activity in the monocytic cell line U937-3κB-LUC. Further enriched arabinoxylan fractions (WUM-BS-LA) from different barley varieties (Tyra, NK96300, SB94897 and CDCGainer) were less active than the mixed-linked β-glucan rich fractions (WSM-TP and WSM-TPX) in the complement-fixing test. The mixed-linked β-glucan rich fraction from NK96300 and CDCGainer showed similar activities as the positive control while mixed-linked β-glucan rich fractions from Tyra and SB94897 were less active. From these results it is concluded that the isolated high molecular weight mixed-linked β-glucans and arabinoxylans from barley show low immunological responses in selected in vitro test systems and thus possible anti-colon cancer effects of barley dietary fiber cannot be explained by our observations.

Structural studies of a heteroxylan from Plantago major L. seeds by partial hydrolysis, HPAEC-PAD, methylation and GC–MS, ESMS and ESMS/MS

The seed mucilage from Plantago major L. contains acidic heteroxylan polysaccharides. For further structural analysis, oligosaccharides were generated by partial acid hydrolysis and then isolated by high-pH anion-exchange chromatography (HPAEC). Each HPAEC fraction was shown by ESMS to contain one major oligosaccharide and several minor components. Partial structures of the oligosaccharides were determined using GC-MS, ESMS and ES tandem mass spectrometry (ESMS/MS). A (1-->4)-linked xylan trisaccharide and (1-->3)-linked xylan oligosaccharides with DP 6-11 suggested that the backbone of the heteroxylan polysaccharide consisted of blocks of (1-->4)-linked and (1-->3)-linked Xylp residues. A (1-->2)-linked Xylp disaccharide and a branched tetrasaccharide were also found, revealing that single Xylp residues are linked to the O-2 of some of the (1-->4)-linked Xylp residues in the backbone. In addition, our results confirm the presence of side chains consisting of the disaccharide GlcpA-(1-->3)-Araf.