Yoshihide Matsuo

Intricatetraol, a halogenated triterpene alcohol from the red alga Laurencia intricata ☆

Abstract A unique halogenated triterpenoid with a C 2 symmetry, named as intricatetraol, has been isolated from the red alga Laurencia intricata , and its structure was deduced from chemical, spectral and biogenetic evidence.

Pannosallene, a brominated C15 nonterpenoid from Laurencia pannosa

Abstract A new C 15 nonterpenoid bromoallene, pannosallene, was isolated from Laurencia pannosa , a Vietnamese species of red algae. Its structure was deduced from spectroscopic data.

Neoisoprelaurefucin, a halogenated C15 non-terpenoid compound from Laurencia nipponica

Abstract A new C 15 nonterpenoid acetylenic compound, named neoisoprelaurefucin, has been isolated from Laurencia nipponica and its structure deduced from spectroscopic data. Neoisoprelaurefucin is a stereoisomer of (3Z)-isoprelaurefucin, which has previously been isolated from this species.

Scanlonenyne, a novel halogenated C15 acetogenin from the red alga Laurencia obtusa in Irish waters

Abstract A novel halogenated acetogenin with a ketonic moiety at C-7, named scanlonenyne, has been isolated from the red alga Laurencia obtusa collected in Irish waters. Its structure was determined by spectroscopic data.

Sesquiterpenoids of Laurencia majuscula (Ceramiales, Rhodophyta) from the Ryukyu Islands, Japan

Two populations of the red alga Laurencia majuscula (Harvey) Lucas (Rhodomelaceae, Ceramiales) from Taketomi Island and Hateruma Island, the Ryukyu Islands, Japan, have been characterized on the basis of both morphological features and halogenated secondary metabolite content. These populations have smaller and more slender thalli than those of other regions. Furthermore, the populations contain two chamigrane‐type Sesquiterpenoids, (2R, 3R, 5S)‐5‐acetoxy‐2‐bromo‐3‐chlorochamigra‐7(14),9‐dien‐8‐one and (2R, 3R)‐2‐bromo‐3‐chlorochamigra‐7(14), 9‐dien‐8‐one, and a laurane‐type sesquiterpenoid, debromoisolaurinterol, as secondary metabolites which are different from those previously reported from other populations. These results are consistent with the concept of ‘chemical races’ within a single species of Laurencia.

Structures of laurenenyne-A and -B, novel halogenated acetogenins from a species of the red agal Laurencia

Abstract Two novel halogenated acetogenins, laurenenyne-A and -B, have been isolated as an inseparable mixture from an undescribed Laurencia species collected in Japan. Their structures including the absolute configuration were determined on the basis of spectroscopic and chemical evidence.

Thyrsiferyl 23-acetate and its derivatives induce apoptosis in various T- and B-leukemia cells

Thyrsiferyl 23-acetate (TF-23A), a cytotoxic compound from marine red alga, induced a rapid cell death in various leukemic T- and B-cell lines. During incubation of Jurkat cells with TF-23A, condensation and fragmentation of nuclei occurred and clusters composed of uneven small cellular particles were formed. Concentration- and time-dependent DNA fragmentation was also induced by the incubation of the cells with TF-23A. These results demonstrate that the TF-23A-induced cell death follows a typical apoptotic process. The TF-23A-induced apoptosis was prevented by fetal calf serum and insulin, but not by EGF or PDGF. TF-23A and its several analogous compounds showed apoptosis-inducing activity. However, only TF-23A out of these compounds showed an inhibitory activity for protein phosphatase 2A, PP2A. These results strongly suggest that a structure of TF-23A involved in induction of apoptosis is different from that involved in the PP2A inhibition.

Morphology and halogenated secondary metabolites of Laurencia snackeyi (Weber–van Bosse) stat. nov. (Ceramiales, Rhodophyta)

The marine red alga known as Laurencia obtusa var. snackeyi (Weber–van Bosse) Yamada (Rhodomelaceae, Ceramiales) is characterized as follows: (1) production of 4 periaxial cells from each axial cell; (2) a few, percurrent, terete, thick main axes arising from a single discoid holdfast without stolon-like branches; (3) alternate-spiral branching; (4) presence of longitudinally oriented secondary pit-connections between contiguous superficial cortical cells; (5) absence of a palisade-like layer; (6) absence of projecting superficial cortical cells; (7) absence of lenticular thickenings in the walls of medullary cells; (8) parallel arrangement of tetrasporangia; and (9) presence of one corps en cerise per superficial cortical cell and trichoblast cell. It differs from L. obtusa (Hudson) Lamouroux in the absence of stolon-like branches with secondary attachment discs and the presence of thicker axes. The following binomial is proposed: Laurencia snackeyi (Weber–van Bosse) Masuda, stat. nov. Halogenated second...