Benzoic Acid Derivatives, Acetophenones, and Anti-inflammatory Constituents from Melicope semecarpifolia

Abstract

Two new benzoic acid derivatives, (E)-3-acetyl-6-(3,7-dimethylocta-2,6-dienyloxy)-2,4-dihydroxybenzoic acid (1) and (E)-3-acetyl-4-(3,7-dimethylocta-2,6-dienyloxy)-2,6-dihydroxybenzoic acid (2), and three new acetophenones, (E)-1-(5-(3,7-dimethylocta-2,6-dienyloxy)-7-hydroxy-2,2-dimethyl-2 H-chromen-8-yl)ethanone (3), (E)-1-(5-(3,7-dimethylocta-2,6-dienyloxy)-7-hydroxy-2-methyl-2-(4-methylpent-3-enyl)-2 H-chromen-8-yl)ethanone (4), and (R,E)-1-(5-(3,7-dimethylocta-2,6-dienyloxy)-3,7-dihydroxy-2,2-dimethylchroman-8-yl)ethanone (5), have been isolated from the fruits of Melicope semecarpifolia, together with eight known compounds. The structures were determined through in-depth NMR and mass spectrometric analyses. Among the isolated compounds, 2-(1'-geranyloxy)-4,6,beta-trihydroxyacetophenone (8), 4-(1'-geranyloxy)-2,6,beta-trihydroxyacetophenone (9), 5-hydroxy-3,7,3',4'-tetramethoxyflavone (10), 5,4'-dihydroxy-3,7,3'-trimethoxyflavone (11), and 5,4'-dihydroxy-3,7-dimethoxyflavone (12) exhibited potent inhibition (IC50<4 microg/mL) on superoxide anion generation and elastase release by human neutrophils in response to fMet-Leu-Phe/cytochalasin B.

A New Long‐Chain Alkene and Antituberculosis Constituents from the Leaves of Pourthiaea lucida

“…The new compound 1 was isolated as colorless needles. EI-MS Analysis of 1 showed the [M] þ ion peak at m/z 448, in agreement with the molecular formula C 32 H 64 (one degree of unsaturation), as confirmed by HR-EI-MS and 13 C-NMR. The presence of a long-chain terminal alkene group in the molecule was revealed by a band at 1651 cm À 1 in the IR spectrum, which was confirmed by signals in the 1 H-NMR spectrum.…”

“…The current phytochemical investigation of the leaves of this plant has led to the isolation of a new long-chain alkene, dotriacont-1-ene (1), along with twelve known compounds, including two a-tocopheroids, a-tocospiro A (2), and a-tocospiro B (3), a benzoquinone, a-tocopheryl quinone (4), a diterpenoid, (E)-phytol (5), a triterpenoid, friedelan-3-one (6), a fatty acid ester, methyl linoleate (7), three steroids, b-sitostenone (8), b-sitosterol (9), and 3b-hydroxystigmast-5-en-7-one (10), and a mixture of hexacosan-1-ol (11), octacosan-1-ol (12), and triacontan-1-ol (13). The structure elucidation of 1 and the antituberculosis properties of the isolated compounds are described herein.…”

“…The locations of the terminal alkene function and terminal Me group were determined by the HMBC experiment ( On the basis of the above data, the structure of compound 1 was identified as dotriacont-1-ene. This was further confirmed by The known isolates, including two a-tocopheroids, a-tocospiro A (2) [5] and atocospiro B (3) [6], a benzoquinone, a-tocopheryl quinone (4) [7], a diterpenoid, (E)-phytol (5) [8], a triterpenoid, friedelan-3-one (6) [9], a fatty acid ester, methyl linoleate (7) [10], three steroids, b-sitostenone (8) [11], b-sitosterol (9) [12], and 3b-hydroxystigmast-5-en-7-one (10) [13], and a mixture of hexacosan-1-ol (11), octacosan-1-ol (12), and triacontan-1-ol (13) [14], were readily identified by comparison of their physicochemical, NMR, and mass-spectrometric data with those of authentic samples or literature values.…”

New Synthetic Routes to Biologically Interesting Geranylated Acetophenones from Melicope Semecarpifolia and Their Unnatural Prenylated and Farnesylated Derivatives

“…The spectral data of synthetic 3 were in agreement with those reported in the literature. 8 Next, the synthesis of naturally occurring geranylated acetophenone 4 was initiated with compound 7 as shown in Scheme 3. Reaction of 7 with citral in the presence of 20 mol % ethylenediamine diacetate in refluxing xylene for 10 h gave cycloadduct 10 in 92% yield.…”

“…1). 8 The roots of this plant have been used as a carminative in folk medicines. 9 Isolated compounds from this plant have demonstrated antiplatelet aggregation 10 and cytotoxic 11 activities that have stimulated interest in the synthesis of naturally occurring acetophenones with geranyloxy groups on the benzene ring.…”