14-Hydroxycaryophyllene 4,5-oxide — A new sesquiterpene fromBetula pubescens
A new sesquiterpene — 14-hydroxycaryophyllene 4,5-oxide — has been isolated from the unsaponifiable part of an ethereal extract of the leaves ofBetula pubescens, and its structure has been established on the basis of chemical and spectral characteristics.
Studies on the Constituents of Buddleja Species. I. Structures of Buddledin A and B, Two New Toxic Sesquiterpenes from Buddleja davidii FRANCH.
Two new piscicidal sesquiterpenes, buddledin A (1) and B (2), have been isolated from the root bark of Buddleja davidii FRANCH. These structures have been deduced on the basis of spectroscopic and chemical evidences, and confirmed by X-ray analysis of the bromohydrin (8). The absolute configuration was determined by the applications of benzoate rule and dibenzoate chirality rule. Buddledin A and B are the first examples of toxic compounds possessing the caryophyllene skeleton.
Melanocins A, B and C, new melanin synthesis inhibitors produced by Eupenicillium shearii. I. Taxonomy, fermentation, isolation and biological properties.
New melanin synthesis inhibitors, melanocins A, B and C, were isolated from the fermentation broth and mycelium extract of Eupenicillium shearii F80695. Melanocin A, an isocyanide compound, inhibited mushroom tyrosinase and melanin biosynthesis of B16 melanoma cells with IC50 value of 9.0 nM and MIC value of 0.9 microM, respectively. Melanocin A also inhibited growth of Streptomyces bikiniensis. While, the structurally very related but non-isocyanide compounds melanocins B and C did not show inhibitory activity in these assays. Melanocins A, B and C showed potent antioxidant activity with scavenging activity of DPPH radical and superoxide anion radical.