Parvaxanthines D-F and Asponguanosines C and D, Racemic Natural Hybrids from the Insect Cyclopelta parva

Mantidisflavin A: A Riboflavin Derivative Featuring a 6/6/6/5/5 Skeleton from the Egg Cases of the Insect Tenodera sinensis Saussure and Its Anti-Renal Fibrosis Activity

Mantidisflavin A (1) was isolated from the egg cases of the Tenodera sinensis Saussure. It exhibits an unprecedented 6/6/6/5/5 skeleton, accompanied by the formation of two additional fused heterocycles through a novel C-C bond and an oxygen bridge on riboflavin backbone. The structure of 1 was identified by spectroscopic and computational methods. To assess the inhibitory effect against renal fibrosis, compound 1 was evaluated in TGF-β1-induced rat kidney epithelial cells, and the results were compared to those of its precursor, riboflavin.

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

Six new compounds, including a tetralone 1, two xanthones 2 and 3, a flavan derivative 4, and two nor-diterpenoids 7 and 8, accompanied by two known flavan derivatives 5 and 6 and a known olefine acid (9) were isolated from whole bodies of Kronopolites svenhedini (Verhoeff). The structures of the new compounds were determined by 1D and 2D nuclear magnetic resonance (NMR) and other spectroscopic methods, as well as computational methods. Selected compounds were evaluated for their biological properties against a mouse pancreatic cancer cell line and inhibitory effects on iNOS and COX-2 in RAW264.7 cells.

Alkyl-modified nucleobases with 6/5/7/5 ring systems from the insect Cyclopelta parva

(±)-Cyclopeltains A and B (1 and 2), two pairs of unusual alkylated adenine derivatives, were isolated from the insect Cyclopelta parva and structurally characterized.