Koji Yamauchi

<b><i>Background/Aims:</i></b> Our previous study confirmed that <i>Aloe</i> sterol stimulates collagen and hyaluronic acid production in human dermal fibroblasts. This study aims to investigate whether <i>Aloe</i> sterol intake affects skin conditions. <b><i>Methods:</i></b> We performed a 12-week, randomized, double-blind, placebo-controlled study to evaluate the effects of oral <i>Aloe</i> sterol supplementation on skin elasticity, hydration, and the collagen score in 64 healthy women (age range 30-59 years; average 44.3 years) who were randomly assigned to receive either a placebo or an <i>Aloe</i> sterol-supplemented yogurt. Skin parameters were measured and ultrasound analysis of the forearm was performed. <b><i>Results:</i></b> ANCOVA revealed statistical differences in skin moisture, transepidermal water loss, skin elasticity, and collagen score between the <i>Aloe</i> sterol and placebo groups. The gross elasticity (R2), net elasticity (R5), and biological elasticity (R7) scores of the <i>Aloe</i> sterol group significantly increased with time. In addition, skin fatigue area F3, which is known to decrease with age and fatigue, also increased with <i>Aloe</i> sterol intake. Ultrasound echogenicity revealed that the collagen content in the dermis increased with <i>Aloe</i> sterol intake. <b><i>Conclusion:</i></b> The results suggest that continued <i>Aloe</i> sterol ingestion contributes to maintaining healthy skin.

Although the antimicrobial activity of lactoferrin has been well described, its mechanism of action has been poorly characterized. Recent work has indicated that in addition to binding iron, human lactoferrin damages the outer membrane of gram-negative bacteria. In this study, we determined whether bovine lactoferrin and a pepsin-derived bovine lactoferrin peptide (lactoferricin) fragment have similar activities. We found that both 20 microM bovine lactoferrin and 20 microM lactoferricin release intrinsically labeled [3H]lipopolysaccharide ([3H]LPS) from three bacterial strains, Escherichia coli CL99 1-2, Salmonella typhimurium SL696, and Salmonella montevideo SL5222. Under most conditions, more LPS is released by the peptide fragment than by whole bovine lactoferrin. In the presence of either lactoferrin or lactoferricin there is increased killing of E. coli CL99 1-2 by lysozyme. Like human lactoferrin, bovine lactoferrin and lactoferricin have the ability to bind to free intrinsically labeled [3H]LPS molecules. In addition to these effects, whereas bovine lactoferrin was at most bacteriostatic, lactoferricin demonstrated consistent bactericidal activity against gram-negative bacteria. This bactericidal effect is modulated by the cations Ca2+, Mg2+, and Fe3+ but is independent of the osmolarity of the medium. Transmission electron microscopy of bacterial cells exposed to lactoferricin show the immediate development of electron-dense "membrane blisters." These experiments offer evidence that bovine lactoferrin and lactoferricin damage the outer membrane of gram-negative bacteria. Moreover, the peptide fragment lactoferricin has direct bactericidal activity. As lactoferrin is exposed to proteolytic factors in vivo which could cleave the lactoferricin fragment, the effects of this peptide are of both mechanistic and physiologic relevance.

The antibacterial properties of enzymatic hydrolysates of bovine lactoferrin were examined to determine whether active peptides are produced from this protein. Hydrolysates prepared by cleavage of lactoferrin with porcine pepsin, cod pepsin, or acid protease from Penicillium duponti showed strong activity against Escherichia coli O111, whereas hydrolysates produced by trypsin, papain, or other neutral proteases were much less active. Low molecular weight peptides generated by porcine pepsin cleavage of lactoferrin showed broad-spectrum antibacterial activity, inhibiting the growth of a number of Gram-negative and Gram-positive species, including strains that were resistant to native lactoferrin. The antibacterial potency of the hydrolysate was at least eightfold greater than that of undigested lactoferrin with all strains tested. The active peptides retained their activity in the presence of added iron, unlike native lactoferrin. The effect of the hydrolysate was bactericidal as indicated by a rapid loss of viability of E. coli O111. The lactoferrin hydrolysate described in the present study has commercial value as a natural preservative agent for use in foods and cosmetics, and as a functional component of new clinical foods for prevention or treatment of gastrointestinal disease.