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Chitosan is a 7V-deacetylated form of chitin. Chitosanase hydrolyzes chitosan into GlcN-oligomers, and many chitosanases have been isolated from microorganisms. Some of these enzymes hydrolyze not only chitosan but also carboxymethyl cellulose (CMC).1-3) In a few studies,4'5) it has been reported that the 7V-acetylglcosamine residues in chitosan are important in the recognition of the substrate by the enzyme, as chitosanases need them to show the highest activity. We found a new type of chitosanase from Bacillus sp. PI-7S,6) which shows the highest activity for chitosan deacetylated 99% and does not hydrolyze CMCat all. In this paper, we describe the properties and the action pattern of the purified enzyme. Chitosanase activity was assayed by the method of 2421 Uchida et al.3) One unit is defined as the amountofenzyme required to liberate 1 /miol of reducing sugar calculated as D-glucosamineper min. The reducing sugar wasmeasured by the method of Schales and Schales.7) Chitosan (the degree of7V-deacetylation, 99%) and chitin were purchased from Cosmo Bio Co., Ltd., CMCand GlcN from Wako Pure Chemical Industries, Ltd., (GlcNAc)5 and GlcNoligomers (dimer to hexamer) from Seikagaku Kogyo Co., Ltd. The other chemicals were obtained from WakoPure Chemical Industries, Ltd. and Sigma Chemical Company.

Partially myristoylated chitosan pyrrolidone carboxylate (PMCP) is a cationic amphiphilic chitosan derivative. Glabridin (Glab) from licorice root extracts is a hydrophobic antimelanogenic agent. Here we assessed the effects of cationic Glab-containing polymeric micelles derived from PMCP (Glab/PMCP-PM) on the ability of Glab to penetrate the skin and inhibit melanogenesis using a human skin model. The amount of Glab absorbed 24 h after the application of Glab/PMCP-PM was approximately four times higher than that of conventional oil-in-water micelles (control) prepared using Tween 60. Further, the release of IL-1α, a mediator of inflammation, was not detected. Treatment with Glab/PMCP-PM significantly increased the inhibition of melanogenesis compared with control. The inhibition of melanogenesis depends upon the enhanced ability of Glab to penetrate the skin, particularly the epidermis. Moreover, the inhibition of melanogenesis and the cationic potential of the Glab/PMCP-PM levels were increased by the cationic phospholipid copolymer. Therefore, Glab/PMCP-PM shows potential as an effective transdermal delivery system for treating skin hyperpigmentation.

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Investigation of partially myristoylated carboxymethyl chitosan, an amphoteric-amphiphilic chitosan derivative, as a new material for cosmetic and dermal application.

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