Studies on the antioxygenic activity of bitter gourd (Momordica charantia) and its fractions using various in vitro models.

BACKGROUND: A study was undertaken to evaluate the antioxygenic activity of bitter gourd pulp and seed powders as well as their various solvent extracts using different methods and to minimise the oxidative deterioration of lipids by natural antioxidants. RESULTS: Bitter gourd pulp and seed powders at 20 g kg(-1) and their ethanol/water extracts exhibited stronger antioxygenic activity than other solvent extracts. Bitter gourd pulp and its extracts showed slightly higher antioxygenic activity than bitter gourd seed and its extracts. This may be attributed to the presence of higher amounts of phenolics and flavonoids, which have been reported as potential antioxidants. The seed portion of bitter gourd contained higher levels of total protein (188.3 g kg(-1) ), total fat (238.9 g kg(-1) ) and crude fibre (350.2 g kg(-1) ) than the pulp portion. Fatty acid analysis of bitter gourd seed oil indicated the presence of α-eleostearic acid, an isomer of conjugated linolenic acid, as a major fatty acid, but this acid was absent in the pulp. CONCLUSION: The results of this study confirmed the presence of antioxygenic compounds in both bitter gourd pulp and seed. In particular, their ethanol/water extracts showed great potential as natural antioxidants to inhibit lipid peroxidation in foods.

Monoclonal antibodies against recombinant hemolysin BL complex of Bacillus cereus.

A three component complex system, designated hemolysin BL (HBL), is believed to be the major diarrheal toxin of Bacillus cereus. Identification of HBL toxin by immunoassay is advantageous over PCR as it detects the expressed form of the gene, thereby differentiating pathogenic strains from nonpathogenic strains. However, most of the immunoassays, like the BCET RPLA kit, are based on the utilization of polyclonal antisera, which show cross-reactivity at times with other Bacillus species. The use of monoclonal antibodies (MAbs) binding specifically to the B. cereus HBL toxin epitopes could be advantageous. To address the problems of non-specificity of the reported detection systems and toxicity of L(1) and L(2) components during expression, we made use of recombinant chimeric rHBL protein to generate murine monoclonal antibodies. From among the L(2) MAbs stabilized, immunoblotting analyses on B. cereus strains revealed nine MAbs to be directed against the hbl D encoded L(1) protein, two to the hbl A encoded B protein, and one with the hbl C encoded L(2) protein. When tested on a large number of B. cereus standard and other related Bacillus species, there was no cross-reactivity observed among the group of MAbs. The presence of HBL component toxins among the strains recovered from food and environmental sources was evaluated by these sets of MAbs and the results compared with that of PCRs for the individual HBL toxin gene components. The HBL toxin profile characterization of the strains by Western blot using MAbs almost matched with the PCR profiles. The MAbs reported here, therefore, can be of immense help in providing the B. cereus identification/detection reliably, rapidly, and at a relatively low cost.