The stratum corneum (SC) of the epidermis acts as a skin permeability barrier, and abnormalities in SC formation lead to several skin disorders. Lipids, especially the epidermisspecific ceramide classes ω-O-acylceramides (acylceramides) and protein-bound ceramides, are essential for skin barrier formation. Ceramide synthase 3 (CERS3) is involved in the synthesis of acylceramides and protein-bound ceramides, and CERS3 mutations cause autosomal recessive congenital ichthyosis. In the present study, we measured ceramide synthase activity and performed comprehensive SC ceramide profiling in an ichthyosis patient with compound heterozygous CERS3 mutations: nonsense mutation p.Arg75* and missense mutation p.Arg229His. The activity of p.Arg75* and p.Arg229His mutant CERS3 proteins was reduced to 4% and 56%, respectively, of the wild-type protein. In the patient's SC, acylceramide levels were greatly reduced, but the levels of protein-bound ceramides remained almost unchanged. Non-acylated ceramide levels were also affected in the patient; in particular, the levels of ceramides composed of sphingosine and non-hydroxy or α-hydroxy fatty acid were substantially higher than in healthy controls. These results suggest that a reduction in acylceramide levels alone leads to ichthyosis. Although protein-bound ceramides are synthesized from acylceramides, levels of acylceramides and protein-bound ceramides are not necessarily correlated.

The heartwood of Pterocarpus marsupium is called as “Asana” in Ayurveda. Its aquatic infusion was used for treating “prameha,” which indicates a polyuria disease in modern medicine. In our research program to investigate a novel agent to improve hyperuricemia, we focused on the extract of Asana as a xanthine oxidase (XOD) inhibitor. Asana extract (50% ethanolic extract, PM-ext) showed 11%, 35%, and 38% inhibition at 50, 200, and 500 µg/mL, respectively. Subsequently, PM-ext was partitioned with ethyl acetate (AcOEt), butanol, and water. Among them, AcOEt-soluble fraction indicated the most potent XOD inhibitory activity and was consecutively fractionated using various liquid chromatography to obtain liquiritigenin (1), isoliquiritigenin (2), and marsupsin (3) as active principles. Compound 1 showed 16% inhibition at 200 µM while 2 showed 20%, 32%, and 46% inhibition at 50, 100, and 200 µM, respectively. Compound 3 showed 15% inhibition at 500 µM. This is the first report on the XOD inhibitory activity of 3. From these results, PM-ext is a promising candidate material for improvement of hyperuricemia. Here, Asana was recognized as an effective material against noncommunicable disease and is expected to be developed as a functional ingredient.