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Tyrosinase is a key enzyme in the biosynthetic pathway of melanin pigments. Abnormal accumulation of melanin pigments causes melasma, freckles, and senile lentigo, which can be substantially ameliorated by treatment with arbutin or other tyrosinase inhibitors. In this study, roots of Angelica koreana Maxim. (Umbelliferae) inhibited melanin production in α-melanocyte stimulating hormone ( α-MSH)-activated B16 melanoma cells or melan-a melanocytes. To elucidate the hypopigmenting principle of A. koreana, the plant extracts were subjected to bioassay-guided phytochemical analysis, resulting in the identification of bisabolangelone. Bisabolangelone dose-dependently inhibited α-MSH-induced melanin production in B16 or melan-a cells with IC(15) values of 9-17 µM. The positive control arbutin also inhibited melanin production in B16 cells with an IC(50) value of 317 µM. Bisabolangelone suppressed α-MSH-inducible protein levels of tyrosinase in B16 cells but could not significantly inhibit the catalytic activity of cell-free tyrosinase. Taken together, this study indicates that bisabolangelone is the primary hypopigmenting principle of A. koreana and may have pharmacological potential in the melanin-associated hyperpigmentation disorders.

Simple and accurate methods to detect the adulteration of commercial aloe gel powder were developed. Crude polysaccharide in aloe gel powder was isolated by precipitating with excess ethyl alcohol and total hexose in isolated polysaccharide was determined by Dubois assay. After hydrolysis of non-dialysable polysaccharides, resultant free sugar was determined by gas chromatography for sugar recognition and ash contents was considered simultaneously. In some products, the content of ash was very low while the content of total hexose was very high. And polysaccharides of these products revealed typical dextran pattern, therefore, these products could be identified that adulterated with commercial maltodextrin. The content of maltodextrin in adulterated product was determined by HPLC and TLC analysis which could be adopted as a part of a certification process.

A sensitive high-performance liquid chromatographic (HPLC) method for the determination of aloesin in plasma was developed. After solid-phase extraction from plasma and derivatization of aloesin and compound AD-1, which was prepared from aloesin as a internal standard, with 9-anthroylnitrile in the presence of quinuclidine, the derivatives were separated on a inertsil ODS-3 column using acetonitrile/methanol/water (3:1:6) as a mobile phase, and detected fluorimetrically at 460 nm with excitation at 360 nm. The detection limit of aloesin was 3.2 ng/ml in plasma (S/N = 3).