Extraction and Partial Characterization of Lectin from Indonesian Brown Algae Padina australis and Padina minor

Extraction and partial characterization of lectin from Indonesian Padina australis and Padina minor had been carried out. The crude extract of the P. australis and P. minor were examined for hemagglutination activity (HA) using native and trypsin-treated of rabbit and human A, B, O type erythrocytes. Both extracts agglutinated all of the trypsin-treated erythrocytes tested in the HA assay. Strong HA was detected in the crude extract of P. minor with trypsin-treated of human type A and O erythrocytes. However, the sugar-binding specificity study through the quantitative hemagglutination inhibition (HI) assay showed that P. minor extract could not specifically recognize the glycans tested. Apparently, the HA of the P. minor was more due to its co-extracted polyphenols content than its lectin content. On the other hand, the HI assay showed that asialo transferrin human (aTf) and asialo porcine thyroglobulin (aPTG) were the most powerful in inhibiting the HA of P. australis. Those indicated that P. australis protein extract was able to specifically recognized aTf and aPTG. The stability of P. australis and P. minor HA over various temperatures, pH ranges, and divalent cations studies showed that the P. minor HA was stable on a wide range of pH and temperature; not affected by the presence of EDTA, but decreased by Ca2+ and Mg2+ additions showed that P. minor protein extract was not a metallic protein. The HA of P. australis decreased at 60 oC and was inactivated at 90 oC; increased at strong acidic (pH 3 & 4) and strong basic (pH 9 & 10) and dependent by the presence of either EDTA or Ca2+ and Mg2+ divalent cation.

Comparative Assessment of Lectin Content in Leaves and Seeds of Two Species of Okra, Abelmoschus esculentus and Abelmoschus caillei

Lectin is a glycoprotein which possesses at least one non-catalyzing domain that specifically and reversibly binds to mono and oligosaccharides. The concentration of lectin in these two species of okra: (A.esculentus and A.caillei) were determined using the glycoprotein agglutinating property with carbohydrate coated surface (erythrocytes) that can easily bind with the lectin present in the two Okra species. The study revealed that A.esculentus has high lectin content in the leaves but the seeds are characterized with low lectin content. Comparatively, A.caillei has low lectin content in its leaves while high level of lectin content was found in its seeds. Protein were extracted and detected by Bradford methods. The data were subjected to analysis using SAS package (L.S.D) version 2009 and it showed that A.esculentus has high protein content in its seeds (0.61 mg/ml) when compared with leaves (0.09mg/ml) of the same species. However, A.caillei has high level protein content in its leaves (0.19mg/ml) as compared with the low protein content found in seeds (0.58mg/ml). The research showed that the A.caillei has high level of lectin but low level of protein contents whereas; the A.esculentus has low level of protein but high level of lectin contents. It is recommended that further studies should be carried out on the genetic compatibility of the two species in order to explore a viable product that would have optimum level of lectin and high level of protein contents in specie of okra.

A survey of domestic species of Basidiomycetes fungi for the presence of lectins inn their carpophores

Preliminary investigations were conducted to determine the presence of active lectins in carpophores of fungi from the class <em>Basidiomycetes</em>, collected from natural localities in southern and south-eastern Poland. The degree of agglutination activity (expressed as the titre of agglutination) of aqueous extracts was determined at room temperature (18-20°C) and at +4°C in respect to human and animal erythrocytes suspended in physiological saline, part of which were additionally treated with proteolytic enzymes. From among the 104 tested species, extracts from 41 of them showed agglutination activity, among which 18 were high. In six cases, specific activity against human ABH group antigens was found. Extracts from 5 species agglutinated only animal erythrocytes, with pigeon erythrocytes being exceptionally sensitive to the lectins. Extracts from two species had distinctly higher agglutination activity at 4°C, which suggests that lectins of the "cold" agglutinin type are present in these species. Analysis of extracts from caps and stems showed that caps had a higher lectin content.

Lipid accumulation in obese Zucker rats is reduced by inclusion of raw kidney bean (Phaseolus vulgaris) in the diet

The effects of inclusion of different levels of raw kidney bean (Phaseolus vulgaris) of high lectin content (27 g/kg meal) in a high-quality (lactalbumin) control diet were tested in nutritional trials on the growth and metabolism of obese Zucker (fafa) rats and their lean littermates in comparison with pair-fed controls. All diets contained 100 g total protein/kg and either 50 g lipids/kg (low fat) or 150 g lipids/kg (moderate fat). The growth of both obese and lean rats on bean diets was retarded by the daily bean intake in a dose-dependent manner. However, most of this was because bean-fed rats contained less body fat than the controls after 10 d. Thus, after feeding low-fat diets containing up to 130 g kidney bean/kg (lectin intake ≤ 0·2 g/kg body weight (BW) per d) in both 10 d and 70 d trials, the bodies of obese rats contained less fat but not protein than their pair-fed controls. Moreover, by increasing the lipid content of the diet to 150 g/kg, the level of bean inclusion could be increased to 280 g/kg (lectin intake ≥ 0·4 g/kg BW per d) without loss of body protein and skeletal muscle. Although these rats contained more body fat than those which were fed on low-fat diets, their weight reduction could be accounted for exclusively by reduced lipid content. In contrast, significant body protein loss occurred when the same diet of high lectin content was fed to lean littermates. Plasma insulin levels were significantly depressed in the obese Zucker rats on bean diets but the pancreas was not significantly enlarged nor its insulin content changed in 10 d trials. However, significant pancreatic growth occurred on long-term (70 d) bean feeding compared with pair-fed controls. The results suggest that, in addition to animal nutrition, it may also be possible to use the bean lectin as a dietary adjunct or therapeutic agent to stimulate gut function and ameliorate obesity if a safe and effective dose-range can be established for human subjects.

Consumption of diets containing raw soya beans (Glycine max), kidney beans (Phaseolus vulgaris), cowpeas (Vigna unguiculata) or lupin seeds (Lupinus angustifolius) by rats for up to 700 days: effect on body composition and organ weights

Feeding trials have been done with rats to assess the effects of long-term (700 d) consumption of diets based on raw cowpeas (Vigna unguiculata; moderate Bowman–Birk inhibitor content, low lectin content), lupin seeds (Lupinus angustifolius; low lectin and protease inhibitor content) or soya beans (Glycine max; high Kunitz inhibitor content, moderate Bowman–Birk inhibitor content, moderate lectin content) or diets containing low levels of raw kidney bean (Phaseolus vulgaris; high lectin content, low Bowman–Birk inhibitor content) on body weight and composition and organ weights. All the legume-based diets reduced feed conversion efficiency and growth rates during the initial 250 d. However, after 250 d the weight gains by rats given legume-based diets were similar to those of controls given the same daily feed intake. Long-term consumption of diets containing low levels of kidney bean significantly altered body composition of rats. The levels of lipid in the body were significantly reduced. As a result, carcasses of these rats contained a higher proportion of muscle/protein than did controls. Small-intestine relative weight was increased by short- and long-term consumption of the kidney-bean-based diet. However, the increase in relative pancreatic weight observed at 30d did not persist long term. None of the other legume-based diets caused any significant changes in body composition. However, long-term exposure to a soya-bean- or cowpea-based diet induced an extensive increase in the relative and absolute weights of the pancreas and caused an increase in the incidence of macroscopic pancreatic nodules and possibly pancreatic neoplasia. Long-term consumption of the cowpea-, kidney-bean-, lupin-seed- or soya-bean-based diets by rats resulted in a significant increase in the relative weight of the caecum and colon.