A glucosidic indole-lignan conjugate with a novel carbon skeleton, named isatindolignanoside A(1), was isolated from an aqueous extract of the Isatis indigotica roots "ban lan gen". Its structure was elucidated by comprehensive analysis of spectroscopic data, including J-and NOESY correlation-based configurational analysis, circular dichroism(CD) data, enzyme hydrolysis, and theoretical ECD calculation. In a preliminary assay, compound 1 showed antiviral activity against Coxsackie virus B3. This compound is the first example of natural product having a structural feature of conjugation between indole and lignan units, and its biosynthetic pathway is postulated.
Lingjie MengQinglan GuoMinghua ChenJiANDong JiangYuhuan LiJiangong Shi
Four stereoisomers of 3,5-bis(2-hydroxybut-3-en-1-yl)-1,2,4-thiadiazole, named insatindigothiadiazoles A–D(1a–1d), were isolated from the roots of Isatis indigotica. Their structures were determined by spectroscopic analysis; specifically, the absolute configurations were assigned by using the MPA determination rule based on Δδ^(RS)values of MPA esters, and supported by electronic CD(ECD)calculations. Proposed biosynthetic pathways and preliminary investigations of the biological activities of 1a–1d against influenza virus A(H3N2), Coxsackie virus B3, and/or HSV-1 are also discussed.
Ming-Hua ChenSheng LinYa-Nan WangCheng-Gen ZhuYu-Huan LiJian-Dong JiangJian-Gong Shi
Two new 2-(quinonylcarboxamino)benzoates, named aconicarmiquinamides A(1) and B(2), were isolated from an aqueous extract of the lateral roots of Aconitum carmichaelii. Their structures were determined by spectroscopic data analysis, and confirmed by comparison with synthetic methyl 3,6-bis(diethylamino)benzoqunonylcarboxylate(3).
Zhi-Bo JiangXian-Hua MengBing-Ya JiangCheng-Gen ZhuQing-Lan GuoSu-Juan WangSheng LinJian-Gong Shi
Four structurally unprecedented aconitane-type C_(19)-diterpenoid alkaloid glycosides with isomeric arabinosyls, named aconicarmichosides A–D(1–4), were isolated from an aqueous extract of "fu zi", the lateral roots of Aconitum carmichaelii. Their structures were determined as neoline 14-O-a-and 14-O-b-L-arabinopyranosides(1 and 2) and 14-O-a-and 14-O-b-L-arabinofuranosides(3 and 4), by spectroscopic and chemical methods including 2D NMR experiments and acid hydrolysis. Compounds 1–4 represent the first examples of glycosidic diterpenoid alkaloids.
Xian-Hua MengQing-Lan GuoCheng-Gen ZhuJian-Gong Shi
Gastrolatathioneine(1),an unusual natural product derived from ergothioneine,a fungal amino acid containing an imidazole-2-thione moiety,was isolated from an aqueous extract of "tian ma"(the Gastrodia elata rhizomes).The structure of 1 including the absolute configuration was determined by extensive spectroscopic data analysis,combined with comparison of an experimental circular dichroism spectrum and calculated electronic circular dichroism spectra of stereoisomers,and confirmed by X-ray crystallography.The natural origin of 1 was proved by HPLC-ESIMS analysis of the crude extract.A biogenetic pathway of 1 is proposed on the basis of metabolic post-modification of ergothioneine that is biosynthesized by a symbiotic fungus.The plant and symbiotic fungus are co-producers of 1.
Qing-Lan GuoSheng LinYa-Nan WangCheng-Gen ZhuCheng-Bo XuJian-Gong Shi
