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A 28-noroleanane-type triterpene oligoglycoside, camellioside E (4), an oleanane-type triterpene oligoglycoside, camellioside F (5), and the known compounds camelliosides A (1) and D (3) were isolated from a 50% EtOH extract of Camellia japonica flower buds from Korea. The principal constituents (1 and 5) significantly inhibited melanogenesis in theophylline-stimulated B16 melanoma 4A5 cells. Camellioside B (2), a major constituent of C. japonica grown in Japan, showed potent inhibition of melanogenesis [95.0 ± 1.0% (p < 0.01) at 20 μM]. The inhibitory effects of 1, 2, and 5 were stronger than that of the reference compound, arbutin. We believe the melanogenesis inhibitory effects of 2 and 5 are partly related to the proliferation inhibitory effects in B16 melanoma 4A5 cells. Conversely, camelliosides tended to enhance proliferation in normal human neonatal skin fibroblasts. Interestingly, camellioside B (2) significantly accelerated fibroblast proliferation. This biological selectivity could make camellioside B useful for treating skin disorders. Herein, we report the first scientific investigation of a triterpene that displays an inhibitory effect on melanogenesis, but that also has an enhancing effect on fibroblast proliferation.

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A Theaceae plant, Camellia (C.) sasanqua THUNB. (Japanese name "sazanka"), which is native to Japan, has been widely cultivated as an ornamental plant in Japanese garden. The flower buds of this plant are used for the similar purpose to those of C. japonica (Japanese name "tsubaki"), which has been used for the treatment of blood vomiting and bleeding due to internal and external injury, and also as antiinflamatory, tonic, and stomachic in Japanese folk medicine. As chemical constituents of this medicinal flower, several hydrolyzable tannins, 2) acylated anthocyanins, 3) and purin alkaloids 4) were reported. However, the pharmacological activities of the flower buds of this plant have not yet characterized. Recently, we have reported the isolation and structure elucidation of triterpene saponins from the flower buds of C. japonica L. (camelliosides A-D), 5,6) C. sinensis L. (chakasaponins I-VI, floratheasaponins A-J), [7][8][9][10][11][12] and C. oleifera ABEL (yuchasaponins A-D).13) Furthermore, those saponins were found to exhibit antiallergic, antidiabetic, antiobestic, gastroprotective, and platelet aggregation activities, etc. 5-13)As a continuation of our studies on bioactive constituents of the flower buds of Camellia species, we found that the methanolic extract and its 1-butanol-soluble fraction from the flower buds of C. sasanqua inhibited an immediate allergic reaction by monitoring the release of b-hexosaminidase from rat basophile leukemia (RBL-2H3) cells. 14) From the 1-butanol-soluble fraction, we have isolated new acylated oleanane-type triterpene saponins termed sasanquasaponins I (1), II (2), III (3), IV (4), and V (5), together with a known saponin, primulagenin15) In addition, we examined the inhibitory effects of sasanquasaponins (1-5) and 6 on the release of b-hexosaminidase from RBL-2H3 cells. In this paper, we describe the isolation and structure elucidaMedicinal Flowers. XXXI. Yamashina-ku, Kyoto 607-8412, Japan: and b Pharmaceutical Research and Technology Institute, Kinki University; 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan. Received August 9, 2010; accepted September 13, 2010; published online September 14, 2010 The methanolic extract and its 1-butanol-soluble fraction from the flower buds of Camellia sasanqua THUNB. were found to show inhibitory activities on the release of b-hexosaminidase from rat basophile leukemia (RBL-2H3) cells. From the 1-butanol-soluble fraction, five new acylated oleanane-type triterpene saponins, sasanquasaponins I-V, were isolated together with a known saponin and their chemical structures were elucidated on the basis of chemical and physicochemical evidence. The principal saponin constituents, sasanquasaponins I-III, with an acyl group at the 22-position of the aglycon part showed the inhibitory effects on the release of b-hexosaminidase and some structure-activity relationships were reported.

On the basis of the fact that selenium (Se) from selenite binds to hemoglobin (Hb), we investigated the missing process in the selenium export from red blood cells (RBCs), i.e., the transfer of selenium bound to Hb to RBC membrane proteins. To elucidate the molecular events of the Hbassociated selenium export from RBC, an Hb-Se complex was synthesized from thiol-exchange of Cys-β93 in Hb with penicillamine-substituted glutathione selenotrisulfide, as a model of major metabolic intermediates, and then interactions between the Hb-Se complex and RBC inside-out vesicles (IOVs) were examined. Selenium bound to Hb was transferred to the IOV membrane on the basis of the intrinsic interactions between Hb and the cytoplasmic domains of Band 3 protein (CDB3). The observed selenium transfer was inhibited by the pretreatments of IOVs with iodoacetamide and the α-chymotrypsin digestion, indicating that the Hb mediates the selenium transfer to the thiol groups of CDB3. In addition, it was found that deoxygenated Hb with a high binding affinity for CDB3 more favorably transferred selenium to the IOV membranes than oxygenated Hb with a low affinity. When selenium export from RBC to the plasma was examined by continuously introducing nitrogen gas, the selenium export rate was promoted with an increase in the rate of deoxygenated Hb. Overall, these data suggested that Hb could possibly play a role in the selenium export from RBC treated with selenite in an oxygen-linked fashion.