Chicken Combs and Wattles as Sources of Bioactive Peptides: Optimization of Hydrolysis, Identification by LC-ESI-MS2 and Bioactivity Assessment.

The production of bioactive peptides from organic by-waste materials is in line with current trends devoted to guaranteeing environmental protection and a circular economy. The objectives of this study were i) to optimize the conditions for obtaining bioactive hydrolysates from chicken combs and wattles using Alcalase, ii) to identify the resulting peptides using LC-ESI-MS2 and iii) to evaluate their chelating and antioxidant activities. The hydrolysate obtained using a ratio of enzyme to substrate of 5% (w/w) and 240 min of hydrolysis showed excellent Fe2+ chelating and antioxidant capacities, reducing Fe3+ and inhibiting 2, 2'-Azino-bis(3-ethylbenz-thiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. The mapping of ion distribution showed that a high degree of hydrolysis led to the production of peptides with m/z ≤ 400, suggesting low mass peptides or peptides with multiple charge precursor ions. The peptides derived from the proteins of cartilage like Collagen alpha-2(I), Collagen alpha-1(I), Collagen alpha-1(III) and elastin contributed to generation of bioactive compounds. Hydrolysates from chicken waste materials could be regarded as candidates to be used as ingredients to design processed foods with functional properties.

Comparative antiandrogenic potency of spironolactone and cimetidine: assessment by the chicken cockscomb topical bioassay.

Spironolactone and cimetidine are effective antiandrogens in vivo, although they differ by five orders of magnitude in affinity for androgen receptors in vitro. To explore this discrepancy, we directly compared the antiandrogenic potency of these two compounds in vivo using the chicken cockscomb topical bioassay. In this assay, the growth of the androgen sensitive cockscomb of immature chicks after stimulation by various doses of androgen (dihydrotestosterone 5, 20, or 100 micrograms/day sc) is inhibited by antiandrogens in cream vehicle applied topically to the cockscomb itself. At low levels of androgen stimulation (5 micrograms/day), 0.5% topical cimetidine produced maximal suppression of cockscomb growth, while at high levels of androgen stimulation 100 micrograms/day), topical cimetidine in concentrations as high as 4% did not suppress cockscomb growth. In contrast, topical spironolactone in concentrations as low as 0.06% produced maximal inhibition of cockscomb growth at all androgen doses. Using an intermediate androgen dose (20 micrograms/day), the minimally effective antiandrogenic concentration of topical cimetidine was between 0.5 and 1.0%, while that for topical spironolactone was less than 0.001%. We conclude that the chicken cockscomb topical bioassay is a useful method for assessing relative potency of antiandrogens. With this method, spironolactone appears to be at least 500 times as strong an antiandrogen in vivo as cimetidine.