Two new cucurbitane-type triterpenes, 24-hydroperoxycucurbita-5,25-dien-3β-ol (1) and 25-hydroperoxycucurbita-5,23-dien-3β-ol (2), were isolated from a MeOH extract of Citrullus lanatus seeds. Compounds 1 and 2 exhibited moderate cytotoxic activities with IC50 values of 33.4–52.4 μM against HL-60 (human leukemia), P388 (murine leukemia), and L1210 (murine leukemia) cells. Compound 1 showed melanogenesis inhibitory activity (melanin content 80.0 %) with low cytotoxicity (cell viability 97.6 %) at a low concentration (10 μM).
LimY.J., LeeE.H., KangT.H., HaS.K., OhM.S., KimS.M., YoonT.J., KangC., ParkJ.H., KimS Y. (2009) Inhibitory effects of arbutin on melanin biosynthesis of α-melanocyte stimulating hormone-induced hyperpigmentation in cultured Brownish guinea pig skin tissues. Archives of Pharmacal Research, 32, 367–373.
9.
YamadaT., MurogaY., JinnoM., KajimotoT., UsamiY., NumataA., TanakaR. (2011) New class of azaphilone produced by a marine fish-derived Chaetomium globosum. The stereochemistry and biological activities. Bioorganic & Medicinal Chemistry, 19, 4106–4113.
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AkihisaT., SeinoK., KanekoE., WatanabeK., TochizawaS., FukatsuM., BannoN., MetoriK., KimuraY. (2010) Melanogenesis inhibitory activities of iridoid-, hemiterpene-, and fatty acid-glycosides from the fruits of Morinda citrifolia (Noni). Journal of Oleo Science, 59, 49–57.
