Prenylated bianthrones and vismione F from Psorospermum febrifugum

The roots of Psorospermum febrifugum collected in Malawi contained together with the known vismione D and geranyloxyemodin four new compounds: vismione F and the three bianthrones A₁, A_3a and A_3b. All the isolated compounds contained C- or O-geranyl substituents and showed a close biogenetic relationship.     

Cytotoxic,hypoglycemic activity and phytochemical analysis of Rubus imperialis (Rosaceae)

Rubus imperialis, Artemia salina, 3-O-methylellagic-4'-O-alpha-rhamnose Acid Screening of different extracts, fractions and compounds from Rubus imperialis Chum. Schl. (Rosaceae) has been conduced using the brine shrimp microwell cytotoxicity assay. Three parts of the plant (methanolic extract from leaves, roots and stems), three fractions from roots (hexane, ethyl acetate and butanol) and three isolated compounds (niga-ichigoside F1, 23-hydroxytormentic acid, ellagic acid derivative) were tested. The most promising material (LC50 <1000 microg/ml) were the methanolic extract and ethyl acetate fraction from roots. However, there was little correlation observed in the degree of toxicities observed between the isolated compounds. On the other hand, the cytotoxicity and in vivo assays confirmed the hypoglycemic activity of methanolic extract and validated the Brazilian popular use of R. imperialis as an antidiabetic agent.     

Three isoflavanones with cannabinoid-like moieties from Desmodium canum

Three further derivatives of 5,7,2',4'-tetrahydroxy-6-methyl isoflavanone have been isolated from the root extract of Desmodium canum and assigned the structures 2,3-dihydro-5,7-dihydroxy-6-methyl-3-(1a,2,3,3a,8b,8c-hexahydro-6-hydroxy-1,1,3a-trimethyl-1H-4-oxabenzo[f]cyclobut[c,d]inden-7-yl)-4H-1-benzopyran-4-one (1) 2,3-dihydro-5,7-dihydroxy-6-methyl-3-(6a,7,8,10a-tetrahydro-3-hydroxy-6,6,9-trimethyl-6H-dibenzo[b,d]pyran-2-yl)-4H-1-benzopyran-4-one (2) 2,3-dihydro-5,7-dihydroxy-6-methyl-3-(3-hydroxy-6,6,9-trimethyl-6H-dibenzo[b,d]pyran-2-yl) 4H-1-benzopyran-4-one (3). The three compounds and the previously isolated chromene 4 all derive from the geranylated precursor 5 by a series of cannabinoid-like oxidative rearrangements.     

Ca2+-independent protein kinase C signalling in mouse eggs during the early phases of fertilization

Protein kinase C (PKC), an enzyme playing a central role in signal transduction pathways, is activated in fertilized mouse eggs downstream of the fertilization Ca2+ signal, to regulate different aspects of egg activation. Given the presence of Ca2+-independent PKC isoforms within the egg, we investigated whether fertilization triggers PKC stimulation in mouse eggs by activating Ca2+-independent signalling pathways. An increase in PKC activity was detected as early as 10 min after the beginning of insemination, when about 90% of eggs had fused with sperm and the first Ca2+ rise was evident in most of the eggs. A similar level of activity was found 20 min later, when about 60% of eggs had resumed meiosis. When the Ca2+ increase was buffered by an intracellular Ca2+ chelating agent, PKC stimulation was not blocked but only slightly reduced. Confocal microscopy analysis revealed that the increase in PKC activity at fertilization coincided with the translocation of PKCdelta, a Ca2+-independent and diacylglycerol-dependent PKC isoform, to the meiotic spindle. When, in the absence of the Ca2+ signal, metaphase-anaphase transition was inhibited, PKCdelta moved to the meiotic spindle but still maintained a sustained cytoplasmic distribution. In summary, our results indicate that: 1) PKC activation is an early event of egg activation; 2) both Ca2+-dependent and Ca2+-independent pathways contribute to increased PKC activity at fertilization; 3) PKCdelta is one of the isoforms participating in this signalling process.     

Styryl- and dihydrostyryl-2-pyrones derivatives from Polygala sabulosa

Two dihydrostyrylpyrones and a styrylpyrone were isolated from Polygala sabulosa, together with five known styrylpyrones. Their structures were established on the basis of spectral evidence as 4-methoxy-6-(11,12-methylenedioxy-14-methoxydihydrostyryl)-2-pyrone, 4-methoxy-6-(11,12-methylenedioxy-10,14-dimethoxydihydrostyryl)-2-pyrone, and 4-methoxy-6-(11,12-methylenedioxy-14-methoxystyryl)-2-pyrone.     

A preliminary study of oscillating electromagnetic field effects on human spermatozoon motility

Some effects of extremely low frequency electromagnetic fields (ELF-EMFs) on human spermatozoa are reported. Significant increases in the values of the motility and of the other kinematic parameters have been observed when spermatozoa were exposed to an ELF-EMF with a square waveform of 5 mT amplitude and frequency of 50 Hz. By contrast, a 5 mT sine wave (50 Hz) and a 2.5 mT square wave (50 Hz) exposure did not produce any significant effect on sperm motility. The effects induced by ELF-EMF (50 Hz; 5 mT) during the first 3 h of exposure persisted for 21 h after the end of the treatment. These results indicate that ELF-EMF exposure can improve spermatozoa motility and that this effect depends on the field characteristics.     

Thymol derivatives from Eupatorium glechonophyllum

The known 10-acetoxy-8,9-epoxythymolisobutyrate and the new 8,9-dihydroxy-10-acetoxythymolisobutyrate and 8,9,10-trihydroxythymol have been isolated from the thallus of Eupatorium glechonophyllum. The acetonide of the last compound was also obtained. The possibility that the new compounds are artefacts is discussed.