Genetic resources of African mahogany in Brazil: genomic diversity and structure of forest plantations.

BACKGROUND: African mahogany species (Khaya sp.) have been introduced to Brazil gaining increasing economic interest over the last years, as they produce high quality wood for industrial applications. To this date, however, the knowledge available on the genetic basis of African mahogany plantations in Brazil is limited, which has driven this study to examine the extent of genetic diversity and structure of three cultivated species (Khaya grandifoliola, Khaya senegalensis and Khaya ivorensis) and their prospects for forest breeding. RESULTS: In total, 115 individuals were genotyped (48 of K. grandifoliola, 34 of K. senegalensis and 33 of K. ivorensis) for 3,330 filtered neutral loci obtained from genotyping-by-sequencing for the three species. The number of SNPs varied from 2,951 in K. ivorensis to 4,754 in K. senegalensis. Multiloci clustering, principal component analysis, Bayesian structure and network analyses showed a clear genetic separation among the three species. Structure analysis also showed internal structure within each species, highlighting genetic subgroups that could be sampled for selecting distinct genotypes for further breeding, although the genetic distances are moderate to low. CONCLUSION: In our study, SNP markers efficiently assessed the genomic diversity of African mahogany forest plantations in Brazil. Our genetic data clearly separated the three Khaya species. Moreover, pairwise estimates of genetic distances among individuals within each species showed considerable genetic divergence among individuals. By genotyping 115 pre-selected individuals with desirable growth traits, allowed us not only to recommend superior genotypes but also to identify genetically distinct individuals for use in breeding crosses.

Swieteliacates S-U, phragmalin limonoids, from the leaves of Swietenia macrophylla.

Three novel phragmalin-type limonoids, swieteliacates S-U (1-3), were isolated from Swietenia macrophylla leaves, alongside four previously identified limonoids (4-7). The structures, encompassing absolute configurations, were delineated through 1D and 2D NMR analyses, high-resolution mass spectrometry (HR-MS), and NMR and ECD calculations. Swieteliacate S (1) is a distinctive cryptate comprising a tricyclo[4.2.110,30.11,4]decane fragment and an additional five-membered oxygen ring. Compounds 3 and 5 exhibited inhibition rates of 26.08 ± 2.26% and 15.42 ± 3.66%, respectively, on triglyceride (TG) production in Hep G2 cells at 40 µM.

Isolation, Characterization, and Antiproliferative Activity of Terpenoids from the Tropical Plant Turraea delphinensis.

The isolation, structure determination, and biological evaluation of constituents from the organic extract of Turraea delphinensis Wahlert (Meliaceae) resulted in the isolation of 51 secondary metabolites, including 14 new terpenoids (six cycloartanes, four tirucallanes/euphanes, three limonoids, and a 7-keto sterol). Among the new compounds, 1 is the first triterpenoid with a trioxaspiro[4.4]nonane side chain, while 11-13 are the first 17-γ-lactone tetranortriterpenoids with four oxygenated functional groups at C-1, -3, -6, and -7. The isolated compounds were evaluated for antiproliferative activity against five human tumor cell lines, including a vinblastine-resistant cell line.

Haperforatones A-M, thirteen undescribed limonoids from Harrisonia perforata with anti-inflammatory activity.

UPLC-Q-TOF-MS combined with mass defect filtering strategies were applied for the phytochemical investigation of Harrisonia perforata, leading to the isolation of thirteen undescribed limonoids named haperforatones A-M (1-13) and seventeen known compounds (14-30). Particularly, haperforatones D-E (4-5) have an unprecedented A, B, C, D-seco-6, 7-nor-C-24-limonoid skeleton, structurally stripped of the five-membered lactone ring B and formed a double bond at the C-5 and C-10 positions. Their 2D structures and relative configurations were identified using spectroscopic data. The absolute configurations of 1, 4, and 6 were established via X-ray diffraction crystallography. All 30 compounds were evaluated for anti-inflammatory potential in LPS-induced Raw 264.7 cell lines. Among those tested compounds, the most potent activity against LPS-induced NO generation was demonstrated by haperforatone F (6), with the IC50 value of inhibition NO production of 7.2 µM. Additionally, 6 could significantly inhibit IL-1ß and IL-6 release and markedly downregulate the protein expression level of iNOS in the LPS-stimulated RAW264.7 cells at 10 µM. The possible mechanism of NO inhibition of 6 was also investigated using molecular docking, which revealed the interaction of compound 6 with the iNOS protein.

Limonoids isolated from Chisocheton ceramicus Miq. and the antiadipogenic mechanism of action of ceramicine B.

Different types of limonoids have been isolated from plants of the Chisocheton genus, notably from the species Chisocheton ceramicus Miq. which is largely distributed in the Indonesian archipelago and Malaysia region. A variety of natural products have been found in the bark of the tree and characterized as antimicrobial and/or antiproliferative agents. The isolated limonoids include chisomicines A-E, proceranolide, and a few other compounds. A focus is made on a large series of limonoids designated ceramicines A to Z including derivatives with antiparasitic activities, antioxidant, antimelanogenic, and antiproliferative effects and/or acting as regulators of lipogenesis. The lead compound in the series is ceramicine B functioning as a potent inhibitor of lipid droplet accumulation (LDA). Extracts from Chisocheton ceramicus and ceramicines have shown anti-LDA effects, with little or no cytotoxic effects. Ceramicine B is the most active compound functioning as a regulator of lipid storage in cells and tissues. Ceramicine B is a transcriptional repressor of peroxisome proliferator-activated receptor γ (PPARγ) and an inhibitor of phosphorylation of the transcription factor FoxO1, acting via an upstream molecular target. Targeting of glycogen synthase kinase-3ß is proposed, based on the analogy with structurally related limonoids known to target this enzyme, and supported by a molecular docking analysis. The target and pathway implicated in ceramicine B activity are discussed. The analysis shed light on ceramicine B as a natural product precursor for the design of novel compounds capable of reducing LDA in cells and of potential interest for the treatment of obesity, liver diseases, and other pathologies.

Excelxylin A: a new seco A-ring tirucallane triterpenoid from the stem bark of Dysoxylum excelsum.

A new seco-A tirucallane triterpenoid named excelxylin A (1), along with two known seco-A triterpenoids (2-3), were isolated from the n-hexane extract of Dysoxylum excelsum (Spreng.) Blume ex G.Don stem bark. The structure and stereochemistry configuration of compounds 1-3 was established by NMR, IR, and HR-ESI-MS spectroscopic data analyses and comparison of their NMR data with literatures. The compounds exhibited the carbon framework for seco-A ring tirucallane triterpenoid, first reported in the Dysoxylum genus. All compounds were tested for their cytotoxicity against human cervical HeLa cells.

Four new tirucallane-type triterpenoids from Aphanamixis polystachya.

Four new tirucallane-type triterpenoids, polystanins H-K (1-4), were obtained from the stems and leaves of Aphanamixis polystachya. Their structures were elucidated by analysis of the spectroscopic data and comparison with literature data. Compounds 1 and 2 showed week inhibitory effects against NO production in LPS-stimulated RAW264.7 cells. All the isolates were investigated for their antifungal activities against drug-resistant Candida albicans.

Nano-emulsion based on Santolina chamaecyparissus essential oil potentiates the cytotoxic and apoptotic effects of Doxorubicin: an in vitro study.

AIM: This study was aimed at investigating the cytotoxic effect of a novel combination of doxorubicin (DOX) and nano-formulation of Santolina chamaecyparissus L. essential oil (SCEO-NANO) on hepatic (HepG2) and colon (HT29) cancer cell lines. METHODS: A nano-emulsion was prepared by high-pressure homogenisation, then analysed by zetasizer and Fourier transform infrared spectroscopy. HepG2 and HT29 cells were used in in vitro tests for apoptosis detection. RESULTS: Formulated droplet size increased in DOX@SCEO-NANO/DOX to 11.54 ± 0.02 with uniform distribution (PDI = 0.13 ± 0.01), when compared with SCEO-NANO (size: 8.91 ± 0.02 nm; PDI = 0.1 ± 0.02). In both cells, DOX@SCEO-NANO/DOX led to a considerable reduction in colony formation. Compared to DOX, apoprotein proteins were overexpressed in HepG2 cells, showing increases of 8.66-fold for caspase-3 and 4.24-fold for the Bax/Bcl-2 ratio. In HT29 cells, ROS-dependent necrosis and apoptosis were seen. Comparing DOX@SCEO-NANO/DOX versus DOX, greater levels of caspase-3 and the Bax/Bcl-2 ratio were observed. CONCLUSION: The DOX@SCEO-NANO/DOX formulation showed potential for targeted eradication of colon adenocarcinoma and hepatocellular carcinoma cells.

Insecticidal Triterpenes in Meliaceae III: Plant Species, Molecules, and Activities in Munronia-Xylocarpus.

Plants of the Meliaceae family have long attracted researchers' interest due to their various insecticidal activities, with triterpenes being the main active ingredients. In this paper, we discuss 93 triterpenoids with insecticidal activity from 37 insecticidal plant species of 15 genera (Munronia, Neobeguea, Pseudocedrela, Nymania, Quivisia, Ruagea, Dysoxylum, Soymida, Lansium, Sandoricum, Walsura, Trichilia, Swietenia, Turraea, and Xylocarpus) in the family Meliaceae. Among these genera, Trichilia deserves further research, with twelve species possessing insecticidal activity. The 93 insecticidal molecules included 27 ring-seco limonoids (comprising 1 ring A-seco group chemical, 1 ring B-seco group chemical, 5 ring D-seco group chemicals, 14 rings A,B-seco group chemicals, 5 rings B,D-seco group chemicals, and 1 rings A,B,D-seco group chemical), 22 ring-intact limonoids (comprising 5 cedrelone-class chemicals, 6 trichilin-class chemicals, 7 havanensin-class chemicals, 2 azadirone-class chemicals, 1 vilasinin-class chemical, and 1 other chemical), 33 2,30-linkage chemicals (comprising 25 mexicanolide-class chemicals and 8 phragmalin-class chemicals), 3 1,n-linkage-group chemicals, 3 onoceranoid-type triterpenoids, 2 apotirucallane-type terpenoids, 2 kokosanolide-type tetranortriterpenoids, and 1 cycloartane triterpene. In particular, 59 molecules showed antifeedant activity, 30 molecules exhibited poisonous effects, and 9 molecules possessed growth regulatory activity. Particularly, khayasin, beddomei lactone, 3ß,24,25-trihydroxycycloartane, humilinolides A-E and methyl-2-hydroxy-3ß-isobutyroxy-1-oxomeliac-8(30)-enate showed excellent insecticidal activities, which were comparable to that of azadirachtin and thus deserved more attention. Moreover, it was noteworthy that various chemicals (such as 12α-diacetoxywalsuranolide, 11ß,12α-diacetoxycedrelone, 1α,7α,12α-triacetoxy-4α-carbomethoxy-11ß-hydroxy-14ß,15ß-epoxyhavanensin, and 11-epi-21-hydroxytoonacilide, etc.) from Turraea showed excellent insecticidal activity. Specially, the insecticidal activity of khayasin from Neobeguea against the coconut leaf beetle were similar to that of rotenone. Therefore, it was a promising candidate insecticide for the control of the coconut leaf beetle.

Insights into the Mechanism of Action of the Degraded Limonoid Prieurianin.

Limonoids are extremely diversified in plants, with many categories of products bearing an intact, rearranged or fragmented oxygenated scaffold. A specific subgroup of fragmented or degraded limonoids derives from the tetranortriterpenoid prieurianin, initially isolated from the tree Trichilia prieuriana but also found in other plants of the Meliaceae family, including the more abundant species Aphanamixis polystachya. Prieurianin-type limonoids include about seventy compounds, among which are dregeanin and rohitukin. Prieurianin and analogs exhibit insecticidal, antimicrobial, antiadipogenic and/or antiparasitic properties but their mechanism of action remains ill-defined at present. Previous studies have shown that prieurianin, initially known as endosidin 1, stabilizes the actin cytoskeleton in plant and mammalian cells via the modulation of the architecture and dynamic of the actin network, most likely via interference with actin-binding proteins. A new mechanistic hypothesis is advanced here based on the recent discovery of the targeting of the chaperone protein Hsp47 by the fragmented limonoid fraxinellone. Molecular modeling suggested that prieurianin and, to a lesser extent dregeanin, can form very stable complexes with Hsp47 at the protein-collagen interface. Hsp-binding may account for the insecticidal action of the product. The present review draws up a new mechanistic portrait of prieurianin and provides an overview of the pharmacological properties of this atypical limonoid and its chemical family.

Toxicity and Metabolomic Dysfunction Invoked by Febrifugin, a Harmful Component of Edible Nut of Swietenia macrophylla.

Swietenia macrophylla fruit is a valuable and historically significant medicinal plant with anti-hypertension and anti-diabetes. We identified a toxic component, Febrifugin, from the edible part of the nut following zebrafish toxicity-guided isolation. Febrifugin is a mexicanolide-type limonoid compound. The toxic factor induced acute toxicity in zebrafish, including yolk sac edema and pericardial edema, reduced body length, decreased melanin deposition, and presented acute skeletal developmental issues. Further exploration of the acute toxicity mechanism through metabolomics revealed that Febrifugin caused significant changes in 13 metabolites in zebrafish larvae, which are involved in the pentose phosphate, tricarboxylic acid (TCA) cycle, and amino acid biosynthesis. The bioassay of oxidative stress capacity and qRT-PCR measurement showed that the compound significantly affected the h6pd gene in the pentose phosphate pathway and the mRNA expression of cs, idh3a, fh, and shda genes in the TCA cycle, leading to reactive oxygen species (ROS) accumulation and a notable decrease in glutathione (GSH) activity in zebrafish. These findings provide a basis for the rational use of S. macrophylla as a medicinal plant and raise awareness of the safety of medicinal plants.

Unusual Vilasinin-Class Limonoids from Trichilia rubescens.

Eight vilasinin-class limonoids, including the unusually chlorinated rubescins K-M (1-3), the 2,3-epoxylated rubescin N (4), and rubescins O-R (5-8), were newly isolated from Trichilia rubescens. The structures of the isolated compounds were determined through spectroscopic and spectrometric analyses, as well as ECD calculations. The natural occurrence of chlorinated limonoids 1-3 was confirmed by chemical methods and HPLC analysis of a roughly fractionated portion of the plant extract. Eight selected limonoids, including previously known and new compounds, were evaluated for antiproliferative activity against five human tumor cell lines. All tested limonoids, except 8, exhibited significant potency, with IC50 values of <10 µM; in particular, limonoid 14 strongly inhibited tumor cell growth, with IC50 values of 0.54-2.06 µM against all tumor cell lines, including multi-drug-resistant cells.

Sequencing and analysis of the complete mitochondrial genomes of Toona sinensis and Toona ciliata reveal evolutionary features of Toona.

BACKGROUND: Toona is a critical genus in the Meliaceae, and the plants of this group are an asset for both restorative and restorative purposes, the most flexible of which are Toona sinensis and Toona ciliata. To concentrate on the advancement of mitochondrial(Mt) genome variety in T.sinensis and T.ciliata, the Mt genomes of the two species were sequenced in high throughput independently, after de novo assembly and annotation to construct a Mt genome map for comparison in genome structure. Find their repetitive sequences and analyze them in comparison with the chloroplast genome, along with Maximum-likelihood(ML) phylogenetic analysis with 16 other relatives. RESULTS: (1) T. sinensis and T.ciliata are both circular structures with lengths of 683482 bp and 68300 bp, respectively. They share a high degree of similarity in encoding genes and have AT preferences. All of them have the largest Phe concentration and are the most frequently used codons. (2) Both of their Mt genome are highly preserved in terms of structural and functional genes, while the main variability is reflected in the length of tRNA, the number of genes, and the value of RSCU. (3) T. siniensis and T. ciliata were detected to have 94 and 87 SSRs, respectively, of which mononucleotides accounted for the absolute proportion. Besides, the vast majority of their SSRs were found to be poly-A or poly-T. (4)10 and 11 migrating fragments were identified in the comparison with the chloroplast genome, respectively. (5) In the ML evolutionary tree, T.sinensis and T.ciliata clustered individually into a small branch with 100% support, reflecting two species of Toona are very similarly related to each other. CONCLUSIONS: This research provides a basis for the exploitation of T.sinensis and T.ciliata in terms of medicinal, edible, and timber resources to avoid confusion; at the same time, it can explore the evolutionary relationship between the Toona and related species, which does not only have an important practical value, but also provides a theoretical basis for future hybrid breeding of forest trees, molecular markers, and evolutionary aspects of plants, which has great scientific significance.

Meliaceae genomes provide insights into wood development and limonoids biosynthesis.

Meliaceae is a useful plant family owing to its high-quality timber and its many limonoids that have pharmacological and biological activities. Although some genomes of Meliaceae species have been reported, many questions regarding their unique family features, namely wood quality and natural products, have not been answered. In this study, we provide the whole-genome sequence of Melia azedarach comprising 237.16 Mb with a contig N50 of 8.07 Mb, and an improved genome sequence of Azadirachta indica comprising 223.66 Mb with a contig N50 of 8.91 Mb. Moreover, genome skimming data, transcriptomes and other published genomes were comprehensively analysed to determine the genes and proteins that produce superior wood and valuable limonoids. Phylogenetic analysis of chloroplast genomes, single-copy gene families and single-nucleotide polymorphisms revealed that Meliaceae should be classified into two subfamilies: Cedreloideae and Melioideae. Although the Meliaceae species did not undergo additional whole-genome duplication events, the secondary wall biosynthetic genes of the woody Cedreloideae species, Toona sinensis, expanded significantly compared to those of A. indica and M. azedarach, especially in downstream transcription factors and cellulose/hemicellulose biosynthesis-related genes. Moreover, expanded special oxidosqualene cyclase catalogues can help diversify Sapindales skeletons, and the clustered genes that regulate terpene chain elongation, cyclization and modification would support their roles in limonoid biosynthesis. The expanded clans of terpene synthase, O-methyltransferase and cytochrome P450, which are mainly derived from tandem duplication, are responsible for the different limonoid classes among the species. These results are beneficial for further investigations of wood development and limonoid biosynthesis.

Munronin V with 7/7/6 tricarbocyclic framework from Munronia henryi harms inhibits tau pathology by activating autophagy.

Munronin V (1), isolated from Munronia henryi Harms, is the first example, to the best of our knowledge, of an unprecedented 7/7/6 tricarbocyclic framework featuring an unusual A,B-seco-limonoid ring. The structures of munronin V were established from extensive spectroscopic and electronic circular dichroism (ECD) analyses. The novel A,B-seco with two seven-membered lactones was formed as a result of Baeyer-Villiger oxidation. Compound 1 activated autophagy and inhibited Tau pathology as revealed by flow cytometric analyses, confocal imaging analysis and western blotting, and this effect was mediated by transcription factor EB (TFEB). These findings suggested that 1 might have potential as a compound for combating Alzheimer's disease.

Flindissone, a Limonoid Isolated from Trichilia prieuriana, Is an LXR Agonist.

In this study, the ability of six limonoids from Trichilia prieuriana (Meliaceae) to activate the liver X receptor (LXR) was assessed. One of these limonoids, flindissone, was shown to activate LXR by reporter-gene assays. Flindissone is a ring-intact limonoid, structurally similar to sterol-like LXR ligands. In endogenous cellular settings, flindissone showed an activity profile that is characteristic of LXR agonists. It induced cholesterol efflux in THP-1 macrophages by increasing the cholesterol transporter ABCA1 and ABCG1 gene expression. In HepG2 cells, flindissone induced the expression of IDOL, an LXR-target gene that is associated with the downregulation of the LDL receptor. However, unlike synthetic and similarly to sterol-based LXR agonists, flindissone did not induce the expression of the SREBP1c gene, a major transcription factor regulating de novo lipogenesis. Additionally, flindissone also appeared to be able to inhibit post-translational activation of SREBP1c. The results presented here reveal a natural product as a new LXR agonist and point to an additional property of T. prieuriana and other plant extracts containing flindissone.

Morphology of pollen grains and orbicules of two threatened species of Cedrela P. Browne (Meliaceae A. Juss.).

Pollen grain morphology and the characterization of additional structures related to pollen dispersion can help to understand the strategies presented by species as well as their taxonomic circumscription. This work investigates the morphology of pollen grains and orbicules of Cedrela fissilis Vell. and Cedrela odorata L., two threatened species of the genus Cedrela P. Browne (Meliaceae A. Juss.) in Brazil. Observations of pollen grains and orbicules of the species were carried out pre- and post-chemical treatment of the samples, under light and scanning electron microscopy, aiming at recognizing structures, detailing morphological characterizations and taking measurements, the last of which were submitted to statistical treatment. The results demonstrate that the pollen grains of the two species are medium in size (measuring between 25 and 50µm), radially symmetrical, isopolar, prolate-spheroidal and 4,5-colporate with subcircular to subquadrangular amb and psilate ornamentation; the orbicules also have a smooth surface and measure about 7 to 10µm. Variation was observed in the size of pollen grains, which presented high coefficient of variation and in the orbicules, as well as in the number of apertures.

Two New Protolimonoids from the Chinese Mangrove Xylocarpus granatum Koenig.

Two new compounds including one apotirucallane protolimonoid, xylogranatriterpin A (1), and one glabretal protolimonoid, xylocarpusin A (2), along with three known related compounds were isolated from the twigs and leaves of the Chinese mangrove Xylocarpus granatum. The apotirucallane xylogranatriterpin A (1) bears an unprecedented 24-ketal carbon connecting ring E with an epoxide ring. The structures of new compounds were elucidated by extensive spectroscopic analysis and by comparison of the spectroscopic data with those reported in the literatures. Plausible biosynthetic pathway to xylogranatriterpin A (1) was also proposed. None of them showed cytotoxic, neuroprotective, or protein tyrosine phosphatase 1B (PTP1B) inhibitory activity.

New steroid produced by Periconia pseudobyssoides K5 isolated from Toona sureni (Meliaceae) and its heme polymerization inhibition activity.

A new ergostane-type steroid named (22E)-3α,6α,9α-ergosta-7,22-diene-3,6,9-triol (1), along with six known steroids 5α,8α-epidioxy-24-ethyl-cholest-6-en-3ß-ol (2), ergosterol-5,8-peroxide (3), cerevisterol (4), isocyathisterol (5), 6ß-hydroxystigmast-4-en-3-one (6), 6ß-hydroxy-4-campesten-3-one (7), were isolated from the fermented unpolished rice media by Periconia pseudobyssoides K5 (Periconiaceae), an endophytic fungus from medicinal plant Toona sureni (Meliaceae). The fermentation takes at 28 ± 2 °C for 30 days. The structure of new steroid (1) was elucidated by extensive spectroscopic measurements (IR, HR-ESI-TOFMS, and 1D and 2D NMR) analyses. The isolated compounds (1-7) were evaluated for heme polymerization inhibition assay (HPIA). The IC50 HPIA value of 1 is 8.24 ± 0.03 mg/ml.

Mexicanolide limonoids from the seeds of Khaya ivorensis with antimicrobial activity.

The methanol extract of the seeds of Khaya ivorensis afforded two new mexicanolide limonoids, ivorensines A and B (1 and 2), together with one known compound, ruageanin D (3). The structures of the isolated compounds were established based on 1 D and 2 D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated limonoids were tested in vitro for antimicrobial potentials against 5 pathogenic microorganisms. As a result, compounds 1-3 exhibited antimicrobial activity against the tested Gram negative bacteria at the minimum inhibitory concentration values less than 50 µg/ml.