Partial Structure of Glycopeptide Obtained from Scytalidium lignicolum Acid Protease A

The partial structure of glycopeptide moiety of new acid protease A isolated from Scytalidium lignicolum ATCC 24568 was studied by Smith degradation, methylation and partial acetolysis techniques. The main product, glycopeptide V (GP-V), obtained by Pronase digestion was composed of mannose, glucosamine, asparagine, serine and glycine in an approximate molar ratio of 10: 3: 2: 1: 1, and a possible structure was proposed as follows:     

Biochemical characteristics and antioxidant activity of crude and purified sulfated polysaccharides from Gracilaria fisheri

Sulfated polysaccharides (SPs) from Gracilaria fisheri of Thailand, which were extracted in low-temperature (25 °C) water showed the highest content of phenolic compounds compared with those extracted at high temperature (55 °C). Crude SP antioxidant activity was evaluated by measuring the DPPH free radical scavenging effect which is directly related to the level of phenolic compounds. The sulfate content, total sugar, and SPs yield were also directly related to the extraction temperature. All extracts contained galactose as a major monosaccharide. High antioxidant activity of crude SP, positively correlated with the phenolic compound contents (R² = 0.996) contributed by the existence of sulfate groups and phenolic compounds. In purified SP, F1 fraction exhibited strong radical scavenging ability, but it was not significantly different compared to crude SP extracted at 25 °C. This indicated that the appropriate density and distribution of sulfate groups in the SP extract showed the best antioxidant activity.     

Expression and Secretion of Scytalidopepsin B,an Acid Protease from Scytalidium lignicolum,in Yeast

An expression and secretion system for scytalidopepsin B, an acid protease from Scytalidium lignicolum, was constructed in yeast. Saccharomyces cerevisiae AH22 was transformed with an yeast-E. coli shuttle vector, pAM82, in which an yeast invertase signal segment and the cDNA encoding the pro- and mature enzyme regions were inserted. The transformant was found to secret a pepstatin-insensitive acid protease, when cultured aerobically in a low phosphate (Pi) medium. Amino terminal amino acid sequencing analysis indicated that the recombinant acid protease was accurately processed and secreted as a mature form.     

A New Antimicrobial Fatty Acid from the Calcareous Sponge Paragrantia cf. waguensis

A new acetylenic fatty acid, 1 , has been isolated from the title sponge. The structure of the molecule was elucidated to contain an enyne and a thiophene by spectroscopic methods. Compound 1 showed a weak cytotoxic effect against NBT‐T2 rat bladder epithelial cells (IC₅₀>20 μg/ml), and antimicrobial activity with minimal‐inhibitory concentrations (MIC) of 64 and 128 μg/ml against Staphylococcus aureus and Escherichia coli, respectively.     

Five New C21-Steroidal Sapogenins from the Acid Hydrolysate of Cynanchum otophyllum Roots

Five new C₂₁-steroidal sapogenins ( 1 – 5 ) named cynotogenins J−N, were isolated from the acid hydrolysate of Cynanchum otophyllum roots. Their structures were established by extensive spectroscopic analysis (UV, IR, HR-ESI-MS, and NMR). Most notably, compounds 1 – 3 harboring a rare 5β,6β-epoxy group in the C₂₁-steroidal skeleton of Cynanchum plants. All compounds were evaluated for their cytotoxicities against multiple cancer cell lines, in which compounds 5 showed weak cytotoxicity against HepG2 cancer cells with IC₅₀ values of 44.90 μM.     

Three New Hydroxyphenylacetic Acid Derivatives and A New Alkaloid from Endophytic Fungus Mortierella sp. in Epimedium acuminatum Franch. and Their Antibacterial Activity

Three new hydroxyphenylacetic acid derivatives, stachylines E-G ( 1 – 3 ), and a new alkaloid, mortieridinone ( 4 ), along with six known compounds ( 5 – 10 ), were isolated from endophytic fungus Mortierella sp. in Epimedium acuminatum Franch. Their structures were determined by their spectroscopic analyses and by comparison with the literature data. Compounds 7 and 10 showed selective antibacterial activity against tested multidrug-resistant bacteria with minimum inhibitory concentration (MIC) values ranging from 25 to 3.13 μg/mL.     

Four New Cryptoporic Acid Derivatives from the Fruiting Bodies of Cryptoporus sinensis,and Their Inhibitory Effects on Nitric Oxide Production

Four new drimane‐type sesquiterpenoid ethers of isocitric acid, named cryptoporic acids J–M, were isolated from the fruiting bodies of Cryptoporus sinensis, together with six known cryptoporic acids. Their structures were elucidated on the basis of extensive spectroscopic analyses. Among them, cryptoporic acid D showed strong inhibition against nitric oxide (NO) production in macrophages with an IC₅₀ of 45.8±3.6 μM , comparable to the positive control of hydrocortisone (IC₅₀ of 40.6±2.5 μM ).