21,20‐Anhydromelianone and Melianone from Simarouba amara (Simaroubaceae); Carbon‐13 NMR Spectral Analysis of Δ<sup>7</sup>‐Tirucallol‐Type Triterpenes

Polonsky, Judith; Varon, Zoīa; Rabanal, Rosa M.; Jacquemin, Henry

doi:10.1002/ijch.197700006

Cited by 36 publications

(13 citation statements)

References 18 publications

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“…Melianol exists as an epimeric mixture in solution (46), with the hemiacetal ring opening and reforming with 2 different stereochemistries at C21. Similar epimeric mixtures have been reported in other protolimonoids containing a hemiacetal ring structure such as turraeanthin (47) and melianone (48) ( SI Appendix , Table S8). Although melianol ( 4 ) has only been isolated 8 times, its C3 ketone melianone has been isolated from a total of 18 species across the Meliaceae, Rutaceae, and Simaroubaceae families ( SI Appendix , Table S8).…”

Section: Resultssupporting

confidence: 77%

Identification of key enzymes responsible for protolimonoid biosynthesis in plants: Opening the door to azadirachtin production

Hodgson

Peña

Stephenson

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

124

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Limonoids are natural products made by plants belonging to the Meliaceae (Mahogany) and Rutaceae (Citrus) families. They are well known for their insecticidal activity, contribution to bitterness in citrus fruits, and potential pharmaceutical properties. The best known limonoid insecticide is azadirachtin, produced by the neem tree (Azadirachta indica). Despite intensive investigation of limonoids over the last half century, the route of limonoid biosynthesis remains unknown. Limonoids are classified as tetranortriterpenes because the prototypical 26-carbon limonoid scaffold is postulated to be formed from a 30-carbon triterpene scaffold by loss of 4 carbons with associated furan ring formation, by an as yet unknown mechanism. Here we have mined genome and transcriptome sequence resources for 3 diverse limonoid-producing species (A. indica, Melia azedarach, and Citrus sinensis) to elucidate the early steps in limonoid biosynthesis. We identify an oxidosqualene cyclase able to produce the potential 30-carbon triterpene scaffold precursor tirucalla-7,24-dien-3β-ol from each of the 3 species. We further identify coexpressed cytochrome P450 enzymes from M. azedarach (MaCYP71CD2 and MaCYP71BQ5) and C. sinensis (CsCYP71CD1 and CsCYP71BQ4) that are capable of 3 oxidations of tirucalla-7,24-dien-3β-ol, resulting in spontaneous hemiacetal ring formation and the production of the protolimonoid melianol. Our work reports the characterization of protolimonoid biosynthetic enzymes from different plant species and supports the notion of pathway conservation between both plant families. It further paves the way for engineering crop plants with enhanced insect resistance and producing high-value limonoids for pharmaceutical and other applications by expression in heterologous hosts.

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Section: Resultssupporting

confidence: 77%

Identification of key enzymes responsible for protolimonoid biosynthesis in plants: Opening the door to azadirachtin production

Hodgson

Peña

Stephenson

et al. 2019

Proc. Natl. Acad. Sci. U.S.A.

124

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“…Based in the above evidence the structure of this compound was thus established as 3β,16β,11α-trihydroxyurs-12-ene (4). The structural assignment was also supported by comparison of the 13 C NMR spectrum ( Table 4) with those of 3β,16βdihydroxyurs-12-ene (11) 7 and 3α,11α-dihydroxyurs-12ene (12). 10 In order to confirm of the assignments for 6a and 8a discussed below, 4 was acetylated.…”

Section: Resulsts and Discussionmentioning

confidence: 76%

Phytochemistry of Trattinnickia burserifolia, T. rhoifolia, and Dacryodes hopkinsii: chemosystematic implications

Lima¹,

Braga²,

Macedo³

et al. 2004

J. Braz. Chem. Soc.

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dammarenediol-II e 3α,20(S)-diidroxidamar-24-eno. Além desses foram ainda isolados o monoterpeno novo 2(S*)-fenilacetoxi-4(R*)-p-menta-1(7),5-dieno, e os triterpenos novos 3βfenilacetoxiurs-12-eno, 3β-fenilacetoxiolean-12-eno e 3β,16β,11α-triidroxiurs-12-eno. Os triterpenos de T. burserifolia, T. rhoifolia e Dacryodes foram analisados em mistura. Os espectros de RMN 13 C mostraram que os principais triterpenos eram α-amirina e estigmasterol em D. hopkinsii. A quimiossistemática da tribo Protieae é discutida.Trattinnickia burserifolia has yielded the known ursanes, α-amyrenone, α-amyrin, 3-epi-αamyrin, 3α,16β-dihydroxyurs-12-ene, the oleananes β-amyrenone, β-amyrin, 3-epi-β-amyrin, 3α,16β-dihydroxyolean-12-ene, the tirucallane acids 3α-hydroxytirucall-8,24-dien-21-oic, 3αhydroxytirucall-7,24-dien-21-oic and 3-oxotirucall-8,24-dien-21-oic, the dammaranes dammarenediol-II and 3α,20(S)-dihydroxydammar-24-ene. Besides it was isolated the new monoterpene 2(S*)-phenylacetoxy-4(R*)-p-mentha-1(7),5-diene and, the new triterpenes 3βphenylacetoxyurs-12-ene, 3β-phenylacetoxyolean-12-ene and 3β,16β,11α-trihydroxyurs-12-ene. The triterpenes from T. burserifolia, T. rhoifolia and Dacryodes were analyzed in mixture. Their 13 C NMR spectra showed that the major triterpenes were in T. burserifolia α-amyrin and β-amyrin; in T. rhoifolia α-amyrin, β-amyrin, 3-epi-α-amyrin, 3-epi-β-amyrin, and lupenone; in T. rhoifolia αamyrin, β-amyrin, 3-epi-α-amyrin, 3-epi-β-amyrin, 3α-hydroxytirucall-8,24-dien-21-oic acid and 3α-hydroxytirucall-7,24-dien-21-oic acid; in D. hopkinsii α-amyrin, β-amyrin, lupeol, tirucallol, sitosterol and stigmasterol. Aspects of chemosystematic of the tribe Protieae are discussed.

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“…Next important step involved in azadirachtin A is the formation of the furan ring, the two CYP450s catalyzing its formation were isolated from M. azedarach and C. sinensis [18]. Two transcripts (transcript/16971 and transcript/16742) in our study were found to be homologs of the two identi ed CYP450s and might produce melianone [66] from its precursor. Transcript/16971 and transcript/16742 expressed highest in leaf and fruit, respectively.…”

Section: Discussionmentioning

confidence: 61%

Multi-tissue transcriptome analysis using hybrid-sequencing reveals potential genes and biological pathways associated with azadirachtin A biosynthesis in neem (Azadirachta indica)

Wang

Wang²,

Huo

2020

Preprint

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Background: Azadirachtin A is a triterpenoid from neem tree exhibiting excellent activities against over 600 insect species in agriculture. The production of azadirachtin A depends on extraction from neem tissues, which is not an eco-friendly and sustainable process. The low yield and discontinuous supply of azadirachtin A impedes further applications. The biosynthetic pathway of azadirachtin A is still unknown and is the focus of our study. Results: We attempted to explore azadirachtin A biosynthetic pathway and identified the key genes involved by analyzing transcriptome data from five neem tissues through the hybrid-sequencing (Illumina HiSeq and Pacific Biosciences Single Molecule Real-Time (SMRT)) approach. Candidates were first screened by comparing the expression levels between the five tissues. After phylogenetic analysis, domain prediction, and molecular docking studies, 22 candidates encoding 2,3-oxidosqualene cyclase (OSC), alcohol dehydrogenase, cytochrome P450 (CYP450), acyltransferase, and esterase were proposed to be potential genes involved in azadirachtin A biosynthesis. Among them, two unigenes encoding homologs of MaOSC1 and MaCYP71CD2 were identified. A unigene encoding the complete homolog of MaCYP71BQ5 was reported. Accuracy of the assembly was verified by quantitative real-time PCR (qRT-PCR) and full-length PCR cloning. Conclusions: By integrating and analyzing transcriptome data from hybrid-seq technology, 22 differentially expressed genes (DEGs) were finally selected as candidates involved in azadirachtin A pathway. The obtained reliable and accurate sequencing data provided important novel information for understanding neem genome. Our data shed new light on understanding the biosynthesis of other triterpenoids in neem trees and provides a reference for exploring other valuable natural product biosynthesis in plants.

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21,20‐Anhydromelianone and Melianone from Simarouba amara (Simaroubaceae); Carbon‐13 NMR Spectral Analysis of Δ⁷‐Tirucallol‐Type Triterpenes

Cited by 36 publications

References 18 publications

Identification of key enzymes responsible for protolimonoid biosynthesis in plants: Opening the door to azadirachtin production

Identification of key enzymes responsible for protolimonoid biosynthesis in plants: Opening the door to azadirachtin production

Phytochemistry of Trattinnickia burserifolia, T. rhoifolia, and Dacryodes hopkinsii: chemosystematic implications

Multi-tissue transcriptome analysis using hybrid-sequencing reveals potential genes and biological pathways associated with azadirachtin A biosynthesis in neem (Azadirachta indica)

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21,20‐Anhydromelianone and Melianone from Simarouba amara (Simaroubaceae); Carbon‐13 NMR Spectral Analysis of Δ7‐Tirucallol‐Type Triterpenes

Cited by 36 publications

References 18 publications

Identification of key enzymes responsible for protolimonoid biosynthesis in plants: Opening the door to azadirachtin production

Identification of key enzymes responsible for protolimonoid biosynthesis in plants: Opening the door to azadirachtin production

Phytochemistry of Trattinnickia burserifolia, T. rhoifolia, and Dacryodes hopkinsii: chemosystematic implications

Multi-tissue transcriptome analysis using hybrid-sequencing reveals potential genes and biological pathways associated with azadirachtin A biosynthesis in neem (Azadirachta indica)

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21,20‐Anhydromelianone and Melianone from Simarouba amara (Simaroubaceae); Carbon‐13 NMR Spectral Analysis of Δ⁷‐Tirucallol‐Type Triterpenes