Synthesis of d-fructose conjugated ligands via C6 and C1 and their corresponding [Ru(bpy)2(L)]Cl2 complexes.

A pyridyl triazole (pyta) modified sucrose ligand was prepared in a seven step synthesis using d-glucose as the protection group for d-fructose and starting from commercially available sucrose. After complexation with Ru(bpy)2Cl2 precursor, the sucrose-conjugated Ru complex of the general formula [Ru(bpy)2(L)]Cl2 was formed. Acidic cleavage of the d-glucose unit led to the first d-fructose conjugated metal complex viad-fructose C6 in literature. Additionally, pyta-modified d-fructose via C1 and the corresponding Ru complex were synthesized. All compounds were analyzed by Rf values, specific rotation, NMR, IR, UV/Vis and fluorescence spectroscopy, mass spectrometry and elemental analysis.

Bacaryolanes A-C, Rare Bacterial Caryolanes from a Mangrove Endophyte.

Caryolanes are known as typical plant-derived sesquiterpenes. Here we describe the isolation and full structure elucidation of three caryolanes, bacaryolane A-C (1-3), that are produced by a bacterial endophyte (Streptomyces sp. JMRC:ST027706) of the mangrove plant Bruguiera gymnorrhiza. By 2D NMR, analysis of the first X-ray crystallographic data of a caryolane (bacaryolane C), CD spectroscopy, and comparison with data for plant-derived caryolanes, we rigorously established the absolute configuration of the bacaryolanes and related compounds from bacteria. Bacterial caryolanes appear as the mirror images of typical plant caryolanes. Apparently plant and bacteria harbor stereodivergent biosynthetic pathways, which may be used as metabolic signatures. The discovery of plant-like volatile terpenes in endophytes not only is an important addition to the bacterial terpenome but may also point to complex molecular interactions in the plant-microbe association.

Xiamycin, a pentacyclic indolosesquiterpene with selective anti-HIV activity from a bacterial mangrove endophyte.

A novel pentacyclic indolosesquiterpene, named xiamycin (1), and its methyl ester (2) have been obtained from Streptomyces sp. GT2002/1503, an endophyte from the mangrove plant Bruguiera gymnorrhiza. The structures were established by 1D and 2D NMR, MS, and X-ray crystallography, and the absolute configuration of 1 was elucidated by the modified Mosher method. Compound 1 exhibits selective anti-HIV activity; it specifically blocks R5 but has no effects on X4 tropic HIV-1 infection. In a panel of cytotoxicity assays, compound 2 showed to be more potent (geometric mean IC(50)=10.13 µM) compared to compound 1 (geometric mean IC(50) >30 µM), with antitumor potency being generally less pronounced. Xiamycin represents one of the first examples of indolosesquiterpenes isolated from prokaryotes.