Sundarbanxylogranins A–E, five new limonoids from the Sundarban Mangrove, Xylocarpus granatum.

Five new limonoids, named sundarbanxylogranins A-E ( 1 – 5 ), were isolated from the seeds of an Indian mangrove, Xylocarpus granatum , collected from mangrove swamps of the Sundarbans, India. The structures of these limonoids were established by HRESIMS and NMR spectroscopic data. Sundarbanxylogranin A ( 1 ) is a rare limonoid containing a bicyclo[5.2.1]dec-3-en-8-one scaffold as the ring A/B-fused core; whereas sundarbanxylogranin B ( 2 ) is a typical mexicanolide with an 8α, 30α-epoxy ring. Sundarbanxylogranins C-E ( 3 – 5 ), among which the former two possess a 29-OMe group with different orientation, belong to a small group of limonoids containing a C 1 - O -C 29 oxygen bridge. Sundarbanxylogranin B exhibited moderate anti-HIV activity with an IC 50 value of 23.14 ± 1.29 μM and a CC 50 value of 78.45 ± 1.69 μM, respectively. [ABSTRACT FROM AUTHOR]