Natural Science Foundation of China[30000213, 30370160, 30670214]; National Basic Research Program of China (973 Program)[2009CB522300]; Chinese Academy of Sciences

Meliaceous limonoids: chemistry and biological activities.

Plant-derived triterpenoids and analogues as antitumor and anti-HIV agents.

Thirty-one nortriterpenoids, including 28 limonoids (1-28) and 3 degraded limonoids (29-31), and one diterpenoid (32), were isolated from the seed extract of Azadirachta indica (neem). Among these, six were new compounds and their structures were established to be 15-hydroxyazadiradione (3), 7-benzoyl-17-hydroxynimbocinol (5), 23-deoxyazadironolide (12), limocin E (13), 23-epilimocin E (14), and 7alpha-acetoxy-3-oxoisocopala-1,13-dien-15-oic acid (32). Upon evaluation of compounds 1-32 on the melanogenesis in the B16 melanoma cells, five compounds, 20, 26, 27, 29, and 31, exhibited marked inhibitory effect (74-91% reduction of melanin content at 25 microg/mL) with no or almost no toxicity to the cells. Seven compounds, 1, 6, 9, 10, 18, 20, and 26, on evaluation for their inhibitory effect against 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation (1 microg/ear) in mice, exhibited, except for compound 26, marked anti-inflammatory activity (ID(50) values 0.09-0.26 mg/ear). In addition, all of the 32 compounds exhibited moderate or potent inhibitory effects (IC(50) values of 230-501 mol ratio/32 pmol TPA) against the Epstein-Barr virus early antigen (EBV-EA) activation induced by TPA. Furthermore, on evaluation of azadirachtin B (21) for its anti-tumor-initiating activity on the two-stage carcinogenesis of mouse skin tumor induced by peroxynitrite (ONOO-; PN) as an initiator and TPA as a promoter, this exhibited marked inhibitory activity.

Melanogenesis inhibitory, anti-inflammatory, and chemopreventive effects of limonoids from the seeds of Azadirachta indicia A. Juss. (neem).

Toona sinensis (Juss.) M.Roem, Meliaceae, a deciduous plant native to eastern and southeastern Asia, is widely used in Traditional Chinese Medicine. This paper was aimed to summarize the current advances in traditional usage, phytochemistry, pharmacology and toxicology of T. sinensis. In this review, various types of data of T. sinensis are discussed in the corresponding parts of this paper, and perspectives for possible future studies of this plant are discussed. The main constituents of T. sinensis are terpenoids, phenylpropanoids and flavonoids, etc., and its pharmacological activities include anti-tumor effects, antioxidant activities, anti-diabetic effects and anti-inflammatory effects. Although a series of phytochemical and pharmacological researches of this plant have been conducted, the active constituents and action mechanism of these activities should be also further explored. Furthermore, the present review also indicates that T. sinensis has potentials to develop into drugs for treating various diseases with high efficacy and low toxicity, particularly in cancer, diabetes and inflammatory disorders. In conclusion, the paper provides a full-scale profile of the traditional usage, phytochemistry, pharmacology and toxicology of T. sinensis, and also provides potential therapeutic uses and drug development prospects of this plant.

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Toona sinensis: a comprehensive review on its traditional usages, phytochemisty, pharmacology and toxicology

Publisher Summary This chapter reviews papers that were published in 2006 on the reactions and syntheses of furans, benzofurans, and their derivatives. Like 2005, many new naturally occurring molecules containing tetrahydrofuran and dihydrofuran rings were identified in 2006. Several examples reported in 2006 demonstrate that 2-substituted furans underwent spirocyclization at the 2-position. The reaction of a furan tethered at the 2-position to an iminium ion gave a spiro-2,5-dihydrofuran derivative as the sole diastereoisomer. This spirocyclization that proceeded irrespective of the length of the carbon linker was employed to construct the ABC tricyclic core of manzamine A. Spirocyclization was also the reaction pathway under radical conditions if furan was tethered to a radical precursor at the 2-position. When furans were tethered to silyl enol ethers at the 2-position, spiroannulation also occurred at the 2-position under electrochemical conditions. Furan that was loaded on a soluble dendritic polyglycerol support could be efficiently oxidized electrochemically to a 2,5-dihydro-2,5-dimethoxyfuran, which served as an intermediate in the synthesis of a pyrrole library.

Chapter 5.3 Five-membered ring systems: Furans and benzofurans

Four new limonoids, 11α-hydroxygedunin (1), 11β-hydroxygedunin (2), 7-deacetoxy-7α,11α-dihydroxygedunin (3), and 7-deacetoxy-7α,11β-dihydroxygedunin (4), were isolated from the cortex of Cedrela sinensis, together with three known compounds, gedunin (5), 7-deacetoxy-7α-hydroxygedunin (6), and 11-oxogedunin (7). The structures of 1−4 were determined by a combination of 2D NMR experiments and chemical methods and by X-ray crystallography of 1 and 2.

Ryota Yamamura

Papers

Hydroxylated gedunin derivatives from Cedrela sinensis.