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Xylocarpus granatum J. König (Meliaceae), commonly known as 'dhundul', is a Bangladeshi mangrove tree, and well distributed in a number of other countries of south-east Asia, Australia and east Africa. Traditionally, X. granatum has been used as an astringent and febrifuge, and also for the treatment of fever, malaria, thrush, cholera, dysentery and diarrhoea in many countries including Bangladesh. Two limonoids, gedunin and 1alpha-hydroxy-1,2-dihydrogedunin, the latter being new, have been isolated from the bark of Xylocarpus granatum by reversed-phase preparative HPLC, and the structures were confirmed by spectroscopic means. The cytotoxic potential of gedunin has been evaluated by the Promega's CellTiter 96 non-radioactive cell proliferation assay using the CaCo-2 colon cancer cell line (IC(50) = 16.83 microM). A summary of the biological activities of gedunin reported to date is also presented.

Reversed-phase preparative HPLC of a methanol extract of the rhizomes of Eremostachys glabra yielded three new iridoid glycosides, namely, 6,9-epi-8-O-acetylshanziside methyl ester, 5,9-epi-penstemoside, and 5,9-epi-7,8-didehydropenstemoside. Their structures were elucidated on the basis of spectroscopic data interpretation. The free-radical scavenging activity of these compounds was assessed using the DPPH assay.

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Key indicatorsSingle-crystal X-ray study T = 120 K Mean '(C±C) = 0.010 A Ê Disorder in solvent or counterion R factor = 0.093 wR factor = 0.190 Data-to-parameter ratio = 7.2 For details of how these key indicators were automatically derived from the article, see

Earlier studies showed that human lens ALDH1A1 plays a critical role in protection against oxidative stress-induced cytotoxicity in human lens epithelial cells (HLEC), and opacification of rat and mouse lens. The complete coding sequence of ALDH1A1 was cloned from human lens cDNA library by using PCR methods and expressed it in Escherichia coli. The cloned human lens ALDH1A1 cDNA encodes a 501-amino-acid protein (molecular mass = 54.8 kD) that is 100% identical to human liver ALDH1A1 and shares significant identity with the same isozyme from other tissues and species. The purified recombinant human lens ALDH1A1 exhibited optimal catalytic activity at pH 8 and preferred NAD+ as cofactor and specifically catalyzed the oxidation of toxic lipid aldehydes such as 4-hydroxynonenal (HNE; Km = 4.8 µM) and malonaldehyde (Km MDA = 3.5 µM). Citral, disulfiram, and cyanamide were found to inhibit human lens ALDH1A1 at IC50 values of 55, 101, and 22610 µM, respectively, whereas diethylstilbestrol (DES) was found to be an activator (EC50, 1.3 µM). Further, modification of recombinant human lens ALDH1A1 with nitric oxide donors such as S-nitroso-N-acetylpenicillamine (SNAP) and S-nitrosoglutathione (GSNO) significantly inhibited the enzyme activity. It therefore appears that activation of ALDH1A1, which efficiently catalyzes the detoxification of lipid-derived toxic aldehydes, and/or prevention of its oxidative modification may be novel therapeutic interventions against oxidative stress-induced lens pathologies.

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