Phragmalin-Type Limonoid Orthoesters from the Twigs of Swietenia macrophylla

Abstract

Swietenia species of family Meliaceae are mainly found in Malaysia, India and Southeast Asia, and many of them have been applied in traditional medicine. [1][2][3][4][5][6] Recently, we reported the isolation and characterization of sixteen D-ring opened phragmalin-type limonoid orthoesters from the twigs and leaves of Swietenia macrophylla which were collected in Hainan Province of People's Republic of China. 7) In a continuation, eleven new phragmalin-type limonoid orthoesters, swietenitins N-X (1-11), as well as a known one epoxyfebrinin B (12), were further isolated from the same plant sample. The stereochemistry of epoxyfebrinin B (12) was completely assigned in the current study. The antimicrobial activities of these isolates against a small panel of microbes were evaluated, but none of them were active. Herein, we report the isolation and structure elucidation of 1-12. Results and DiscussionSwietenitins N-Q (1-4) and Epoxyfebrinin B (12) Swietenitin N (1), a colorless crystal, had the molecular formula C 39 H 48 O 15 as determined by high resolution-electron ionization-mass spectra (HR-EI-MS) at m/z 756.2970 [M] ϩ (Calcd 756.2993), which was supported by the protonated and sodiated molecular ions at m/z 756 [MϩH] ϩ and 779 [MϩNa] ϩ in the positive mode of electrospray ionization (ESI)-MS, respectively. The IR absorption peaks at 3537 and 1743 cm Ϫ1 implied the presence of hydroxyl and ester carbonyl groups. 13C-NMR and distortionless enhancement by polarization transfer (DEPT) spectra displayed 39 carbon resonances comprising nine methyl (one methoxyl), six methylenes, six sp 3 methines (four oxygenated), nine sp 3 quaternary carbons (six oxygenated), five carbonyl and two double bonds. Furthermore, a combined analysis of its 1 H-and 13 C-NMR data (Tables 1, 2) revealed the presence of one acetyl, an orthoacetate group, a b-furyl ring, a propionyloxy group and an 2,3-epoxy-2-methyl-butyryl moiety. There are sixteen unsaturations in the molecule of 1, of which, nine degrees are occupied by five ester carbonyls, 2,3-epoxy-2-methyl-butyryl moiety and the b-furyl ring, and the remaining seven degrees required 1 being heptacyclic at the central core. The aforementioned data suggested that 1 was a phragmalin-type limonoid orthoester.Extensive analysis of 2D-NMR spectra, especially heteronuclear multiple bond correlation (HMBC), allowed the assignment of the most functional groups to the limonoid core and confirmed the framework of a phragmalin-type limonoid for 1. In the HMBC (Fig. 1A), the key correlations of H 2 -29/C-1, C-2, C-4, C-28 and C-10, and H-30/C-3, C-2, C-8 and C-9 revealed 1 being a B-seco phragmalin-type limonoid. The carbon resonances at d 170.4 and 78.8 were assignable to C-16 and C-17 by the HMBC correlations between H 2 -15 and C-16, and between H 3 -18 and C-17, respectively, indicating the existence of the ring D of a six-membered lactone.8) The quaternary carbon at d 118.8 (C-31) correlating with a methyl at d 1.67 (s) revealed the presence of a typical orthoacetate moiety. The HMBC...

Wood typification by Venturi easy ambient sonic spray ionization mass spectrometry: the case of the endangered Mahogany tree

“…Previous phytochemical studies and current high‐resolution MS and MS/MS data (Fig. ) allowed us to suggest that these unique phytochemical markers are sodiated molecules of phragmalin‐type limonoids typical for the Mahogany wood.…”

Chemical Constituents from the Barks of Swietenia macrophylla

“…The EtOAc layer was subjected to vari- ous column chromatographies to yield a new tirucallane-type triterpenoid, sweitenitol (1). In addition, 15 known compounds were identified to be agladupol D (2), [7] 21α-meliandiol (3), 21α-methylmeliandiol (4), [8] protoxylocarpins F (5), [ 9 ] methyl 1α-acetoxy-6,8α,14β,30β-tetrahydroxy-3-oxo-[3.3.1 10,2 .1 1,4 ]-tricyclomeliac-7-oate (6), [10] seneganolide (7), [11] methyl 1α-acetoxy-2β,3α,6,8α,14β-pentahydroxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate (8), [10] methyl 1α-acetoxy-3β,6,8α,-trihydroxy-2α-methoxy-2β,14β-epoxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate (9), [12] 1-acetylkhayanolide B (10), [13] (＋)-catechin (11), aromadendrin (12), [14] ivorenolide A (13), [15] 24-methylenecycloartanol (14), [16] β-sitosterol (15), and daucosterol (16) by comparison of their spectroscopic data and physicochemical properties with data reported in the literatures.…”

“…[1] Its seeds have been used as a folk medicine for treatment of diabetes, hypertension, and malaria in Malaysia. [2] Previous chemical investigation of Swietenia macrophylla led to the isolation of a number of limonoids, [3,4] steroids [5] and polyphenols, [6] which showed a wide spectrum of biological effects, such as anti-viral, anti-inflammatory, anti-infective, anti-mutagenic, and anti-diabetic activities. [2] In this paper, a new tirucallane-type triterpenoid, swietentol (1), was isolated from the barks of S. macrophylla, along with four known triterpenoids (2)(3)(4)(5), five known limonoids (6)(7)(8)(9)(10), and other six compounds (11)(12)(13)(14)(15)(16).…”

Triterpenoids

“…A similar range of phragmalin derivatives, swietenitins N-X 347-357, has been isolated from the twigs of Swietenia macrophylla. 147 The structure of swietenitin N 347 was conrmed by X-ray analysis. The stereochemistry of the known compound 14,15-dihydroepoxyfebrinin B 358 was also established during this study.…”