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The seeds of the medicinal plant Caesalpinia sappan yielded fourteen cassane-type diterpenes, including six new rearranged ones named as caesalppans A-F (1-6). Their structures were elucidated by spectroscopic analysis and comparison with literature data. The isolated new compounds 1-6 possess lactone-type cassane diterpenoid skeleton with an oxygen bridge between C-19 and C-20, and were tested cytotoxic activity against four cancer cell lines using the MTT method.

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 C1-O-C29 oxygen bridge. Sundarbanxylogranin B exhibited moderate anti-HIV activity with an IC50 value of 23.14±1.29μM and a CC50 value of 78.45±1.69μM, respectively.

Two new furanoeremophilanes, 1α, 6α-epoxy-9-oxo-10β-hydroxyl-furanoeremophilane (1), and 9-oxo-1α, 6β, 10β-trihydroxy-furanoeremophilane (2) were isolated from Senecio nemorensis. Their structures were elucidated by spectroscopic methods and X-ray crystallography. This is the first report of the isolation of the C1-C6 oxygen bridge of furanoeremophilane. Their cytotoxic effects on BEL7402 and NF-KB cell lines were tested.

Four new limonoids, named granatumins V-Y (1-4), belonging to the small group of limonoids with a C-1-C-29 oxygen bridge and a Delta(8,30) double bond, were isolated from the seeds of an Indian mangrove, Xylocarpus granatum, collected in the swamp of Krishna estuary, Andhra Pradesh. The constitutions and absolute configurations of these compounds were established by extensive NMR investigations, single-crystal X-ray crystallography using Cu K alpha radiation, and by the comparison of circular dichroism spectrum. (C) 2014 Elsevier B.V. All rights reserved.