Aglatestine A, a Rearranged Limonoid with a 3/6/6 Tricarbocyclic Framework from the Fruits of Aglaia edulis

Aglatestine A (1), an unprecedented 3/6/6 tricarbocyclic limonoid framework along with four biogenic A/D-seco limonoid analogues with rare beta-substituents at C-6 (2-5), was discovered from the fruits of Aglaia edulis. The structures of 1-5 along with their absolute configurations were clarified using methods of HRMS(ESI), NMR, electronic circular dichroism, X-ray diffraction crystallography, and quantum chemical calculations. The plausible biogenetic speculation suggested that an electrophilic cyclization between C-1 carbocation from acetolysis and electron-rich C-5 from enolization of C=O of 2 may play a key role. The biological evaluation showed that 5 exhibited anti-inflammatory activity indicated by inhibiting NO release in LPS-activated RAW 264.7 macrophages (IC50: 35.72 +/- 1.96 mu M).

Automated summary

A novel 3/6/6 tricarbocyclic limonoid, Aglatestine A (1), and four biogenic A/D-seco limonoid analogues (2-5) with rare beta-substituents at C-6 were discovered from the fruits of Aglaia edulis. Various methods were used to confirm the structures and absolute configurations of these compounds. Biological evaluation revealed that one of the compounds exhibited anti-inflammatory activity.