Structure and Neurotrophic Activity of seco-Prezizaane-Type Sesquiterpenes from Illicium merrillianum

Huang, Jianmei; Yokoyama, Ritsuko; Yang, Chunshu; Fukuyama, Yoshiyasu

doi:10.1021/np0005715

Cited by 92 publications

(57 citation statements)

References 11 publications

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“…Fractions A-E were purified by various types of chromatography to afford new compounds, as described in our previous papers. [7][8][9][10][11][12][13][14] Our further studies of the residual fractions E, D, and C led to the isolation of seven new sesquiterpenes 1-7. This paper deals with the isolation and structural elucidation of these new sesquiterpenes.…”

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“…We have continued chemical studies on the pericarps of Illicium merrillianum since 1999. As results, about 36 structurally novel sesquiterpenes have been isolated from this species [7][8][9][10][11][12][13][14] and classified into the seco-prezizaane, anislactone, and allo-cedrane types. It is worthy of note that an anislactone-type compound, merrilactone A, isolated from this plant shows interesting neurotrophic activity.…”

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Seven Novel seco-Prezizaane-Type Sesquiterpenes from the Pericarps of Illicium merrillianum

Huang¹,

Yang

Zhao³

et al. 2004

Chem. Pharm. Bull.

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The genus Illicium is a rich source of prenylated C 6 -C 3 compounds, 1-3) neolignans 4) and seco-prezizaane-type sesquiterpenes. 5,6) These compounds belong to unique structural types and occur exclusively in Illicium species and are considered to be characteristic chemical markers of Illicium species. The former two types are usually accumulated in the stem bark, root bark, and leaves. However, most sesquiterpenes tend to be biosynthesized in the fruit. We have continued chemical studies on the pericarps of Illicium merrillianum since 1999. As results, about 36 structurally novel sesquiterpenes have been isolated from this species [7][8][9][10][11][12][13][14] and classified into the seco-prezizaane, anislactone, and allo-cedrane types. It is worthy of note that an anislactone-type compound, merrilactone A, isolated from this plant shows interesting neurotrophic activity.14) Thus it has attracted synthetic organic chemists due to its structural complexity and outstanding biological activity. 15) Those results inspired us to undertake the systematic studies on I. merrillianum. The methanol extract of I. merrillianum was first separated into fractions A-G (see Experimental). The main chemical constituent of fractions F and G was shikimic acid. Fractions A-E were purified by various types of chromatography to afford new compounds, as described in our previous papers. [7][8][9][10][11][12][13][14] Our further studies of the residual fractions E, D, and C led to the isolation of seven new sesquiterpenes 1-7. This paper deals with the isolation and structural elucidation of these new sesquiterpenes.Compound 1 had the molecular formula C 15 H 22 O 5 , as established by high-resolution (HR) FAB-MS at m/z 305.1352 [MϩNa] ϩ . In its IR spectrum, the absorptions at 3389 and 1728 cm Ϫ1 showed the presence of a hydroxyl and a carbonyl group, respectively. The 1 H-NMR spectral data of 1 (Table 1) contained signals characteristic of pseudoanisatin (8), 16) except for the absence of an oxygenated proton signal at d H 4.80 (1H, m) due to H-3a in 8 and the presence of signals for a methylene group at d H 1.70 (ddd, Jϭ13.5, 9.5, 3.3 Hz) and d H 2.60 (ddd, Jϭ13.5, 11.8, 5.5 Hz), which were assignable to H-3b and H-3a. These structural data showed that 1 is pseudoanisatin (8) without a hydroxyl group at the C-3 position. The 1 H-1 H correlation spectroscopy (H-detected heteronuclear multiple-quantum coherence (HMQC), and 1 H-detected heteronuclear multiple-bond connectivity (HMBC) data confirmed the planar structure of 1. The relative configurations for chiral centers C-1 and C-6 were determined to be the same 1R* and 6R* as those of 8 by nuclear Overhauser effect spectroscopy (NOESY), in which CH 3 -15 showed cross-peaks to H-10a and H-8b, and CH 3 -12 showed a cross-peak to H-14a. Thus 1 was assigned to be 3-deoxypseudoanisatin. Ϫ1. The 1 H-and 13 C-NMR spectral data (Table 1) suggested that 2 is 6-deoxypseudoanisatin (11) 16) bearing a hydroxyl group at the C-2 position. The H-2 signal at d Yamashiro-cho, Tokushima 770-8...

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Seven Novel seco-Prezizaane-Type Sesquiterpenes from the Pericarps of Illicium merrillianum

Huang¹,

Yang

Zhao³

et al. 2004

Chem. Pharm. Bull.

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“…Isolated from the pericarps of Illicium merrillianum, 11-O-debenzoyltashironin has been claimed to induce neurite outgrowth in rat cortical neurons at concentrations as low as 0.1 µM. 33 This highly oxygenated, densely functionalized natural product was targeted for total synthesis in our laboratory as part of our neurotrophin-based research program (Scheme 14). Upon examining the structure of 11-Odebenzoyltashironin, we formulated an overarching strategy, wherein virtually the entire tetracyclic framework of the target would be fashioned through a complexity-building oxidative dearomatization (I2fI3)-transannular Diels-Alder cascade sequence (I3fI4).…”

Section: Discussion: Snapshots In Recent Total Synthesismentioning

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Pattern Recognition in Retrosynthetic Analysis: Snapshots in Total Synthesis

Wilson

Danishefsky

2007

J. Org. Chem.

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In this Perspective, the value of small molecule natural products (SMNPs) in the discovery of active biological agents is discussed. The usefulness of the natural products-based method of potential pharma discovery is much augmented by the capacities of chemical synthesis. The great advances in synthetic methodology allow for major editing of the natural product in the hopes of optimizing potency and therapeutic index. As a consequence of the enormous increase in the power of multistep chemical synthesis, one can now approach structures of previously impractical complexity. In constructing a plan for a multistep synthesis, two complementary thought styles are often encountered. One is the traditional and extremely powerful concept of prioritized strategic bond disconnections. The other, which we term “pattern recognition,” involves the identification of moieties within the target, which are associated with reliable chemistry, and can serve to facilitate progress to the target. Recognition of such targets may require substantial recasting of the target structure to connect it to well-established types of transformations. Some of our older ventures, where ideas about pattern recognition were first being fashioned and used productively, are revisited. In addition, we provide snapshots of recently achieved total syntheses of SMNPs of novel biological potential. These vignettes serve to harmonize insights occasioned by pattern recognition, in concert with transformations enabled by the enormous growth in the power of synthesis.

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“…To date, we have reported the isolation of 15 new seco-prezizaane-type and four novel anislactone-type sesquiterpenes from this plant. [4][5][6][7][8] Our screening program found that the methanol extract of I. merrillianum showed brine shrimp lethal activity. The percentage of deaths of the methanol extract was 37% at 200 mg/ml.…”

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“…2) Three neurite outgrowth-promoting sesquiterpenes, isodunianin, 3) and merrilactone A 4) and 11-O-debenzoyl tashironin, 5) have so far been isolated from I. tashiroi and I. merrillianum, respectively. We have continued to investigate the chemical constituents of the pericarps of I. merrillianum collected in Yunnan Province, China, and locally used as an antirheumatic agent.…”

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Brine Shrimp Lethality Test Active Constituents and New Highly Oxygenated Seco-prezizaane-Type Sesquiterpenes from Illicium merrillianum.

et al. 2002

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Structure and Neurotrophic Activity of seco-Prezizaane-Type Sesquiterpenes from Illicium merrillianum

Cited by 92 publications

References 11 publications

Seven Novel seco-Prezizaane-Type Sesquiterpenes from the Pericarps of Illicium merrillianum

Seven Novel seco-Prezizaane-Type Sesquiterpenes from the Pericarps of Illicium merrillianum

Pattern Recognition in Retrosynthetic Analysis: Snapshots in Total Synthesis

Brine Shrimp Lethality Test Active Constituents and New Highly Oxygenated Seco-prezizaane-Type Sesquiterpenes from Illicium merrillianum.

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