Antifeedant rings B and D opened limonoids from Khaya senegalensis

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.

Cheminformatics-Based Study Identifies Potential Ebola VP40 Inhibitors

The Ebola virus (EBOV) is still highly infectious and causes severe hemorrhagic fevers in primates. However, there are no regulatorily approved drugs against the Ebola virus disease (EVD). The highly virulent and lethal nature of EVD highlights the need to develop therapeutic agents. Viral protein 40 kDa (VP40), the most abundantly expressed protein during infection, coordinates the assembly, budding, and release of viral particles into the host cell. It also regulates viral transcription and RNA replication. This study sought to identify small molecules that could potentially inhibit the VP40 protein by targeting the N-terminal domain using an in silico approach. The statistical quality of AutoDock Vina’s capacity to discriminate between inhibitors and decoys was determined, and an area under the curve of the receiver operating characteristic (AUC-ROC) curve of 0.791 was obtained. A total of 29,519 natural-product-derived compounds from Chinese and African sources as well as 2738 approved drugs were successfully screened against VP40. Using a threshold of −8 kcal/mol, a total of 7, 11, 163, and 30 compounds from the AfroDb, Northern African Natural Products Database (NANPDB), traditional Chinese medicine (TCM), and approved drugs libraries, respectively, were obtained after molecular docking. A biological activity prediction of the lead compounds suggested their potential antiviral properties. In addition, random-forest- and support-vector-machine-based algorithms predicted the compounds to be anti-Ebola with IC50 values in the micromolar range (less than 25 μM). A total of 42 natural-product-derived compounds were identified as potential EBOV inhibitors with desirable ADMET profiles, comprising 1, 2, and 39 compounds from NANPDB (2-hydroxyseneganolide), AfroDb (ZINC000034518176 and ZINC000095485942), and TCM, respectively. A total of 23 approved drugs, including doramectin, glecaprevir, velpatasvir, ledipasvir, avermectin B1, nafarelin acetate, danoprevir, eltrombopag, lanatoside C, and glycyrrhizin, among others, were also predicted to have potential anti-EBOV activity and can be further explored so that they may be repurposed for EVD treatment. Molecular dynamics simulations coupled with molecular mechanics Poisson–Boltzmann surface area calculations corroborated the stability and good binding affinities of the complexes (−46.97 to −118.9 kJ/mol). The potential lead compounds may have the potential to be developed as anti-EBOV drugs after experimental testing.

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.

Antimicrobial mexicanolide limonoids from the seeds of Khaya senegalensis

Three new mexicanolide limonoids were obtained from the 90% ethanol extract of the seeds of Khaya senegalensis. Their structures were elucidated as senegalenines A-C (1-3) by analysing their 1D/2D NMR and MS spectroscopic analysis. In addition, the isolated limonoids were tested in vitro for antimicrobial potentials against 5 pathogenic microorganisms. Consequently, compounds 1-3 exhibited antimicrobial activity against the tested Gram negative bacteria at the minimum inhibitory concentration values less than 40 μg/ml.

Chemical characterization, antimicrobial, antioxidant, and cytotoxic potentials of Swietenia mahagoni

Infectious diseases are the most important cause of death worldwide. Many of these diseases show great resistance to drugs and antibiotics with long-term use. Extracts of some medicinal plants have antimicrobial properties, which can treat and overcome these diseases. Meliaceae is a family of timber trees used extensively in treating many bacterial and fungal diseases, especially Swietenia mahagoni (L.) Jacq. In this study, phytochemical screening, gas chromatography/mass spectrometry (GC/MS) analysis, and antimicrobial, antioxidant, and antitumor activities of the methanolic extract of S. mahagoni (L.) leaves were performed. Phytochemical screening exhibited the presence of alkaloids, flavonoids, saponins, phenols, triterpenoids, glycosides, and tannins. GC/MS analysis exhibited 40 compounds, mainly 7-hexadecene, (Z)-, imidazole-4,5-d2, and 1-acetyl-4,4-bis[4-(3-bromopropoxy)-3,5-dimethoxyphenyl] piperidine. The antibacterial and antifungal potentials of the methanolic extract of S. mahagoni (L.) leaves was investigated using the agar well diffusion technique. Potent antibacterial activity against Staphylococcus aureus, Escherichia coli, Salmonella enterica, Enterobacter aerogenes, and Proteus vulgaris and antifungal activity against Aspergillus flavus, Aspergillus niger, and Candida albicans were found. The minimum inhibitory concentration and minimum bactericidal and fungicidal concentrations ranged from 12.5 to 25 mg/mL. Antioxidant activity was studied using the free radical scavenging assay, and the IC₅₀ value of the leaf extract was 69.9 µg/mL. Cytotoxic activity was screened using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the IC₅₀ value was 44.2 µg/mL. These findings suggested the importance of this plant in treating some bacterial and fungal infections and cancer.

Furan fragment isomerized andirobin-type limonoids from the stem barks of Khaya senegalensis

A new andirobin-type limonoid with modified furan ring, khaysenelide K (1), together with a known analogue (2), was isolated from the stem barks of Khaya senegalensis. The structure and absolute configuration of 1 were elucidated by a combination of 1D and 2D NMR, HRESIMS, and single-crystal X-ray diffraction using mirror Cu-Kα radiation. Compound 1 showed moderate NO inhibitory activity in LPS-activated RAW 264.7 macrophages with IC₅0 value of 27.74 ± 0.68 μM.[Formula: see text].

Biological activities of limonoids in the Genus Khaya (Meliaceae): a review

Background

Limonoids are a class of highly oxygenated modified triterpenoids with a diverse range of biological activities. Although with restricted occurrence in the plant kingdom, these compounds are found extensively in the Meliaceae and Rutaceae families. Limonoids are of great interest in science given that the small number of plant families where they occur exhibit a broad range of medicinal properties that promote health and prevent disease.

Main text

The Meliaceae family includes the genus Khaya and comprises tree species that have been used in traditional medicine to treat several ailments. In recent years, the genus Khaya has attracted much research interest owing to the presence of limonoids in different plant parts of a few species that can serve as therapeutic molecules in the pharmaceutical industry. In this study, a literature search over the past two decades (2000–2020) was conducted on the biological activities of limonoids in the genus Khaya using different databases such as Google Scholar, PubMed, Scopus and ISI Web of Science. The taxonomy, geographical distribution and the various traditional uses of the genus are presented in detail. This study reveals that the currently documented biological activities of limonoids both in vivo and in vitro are limited to four species (K. anthotheca, K. grandifoliola, K. ivorensis and K. senegalensis) in the genus Khaya, and include anticancer, antimalarial, hepatoprotection, anti-inflammatory, neuroprotection, antimicrobial, antifungal and antifeedant. The most well-researched species, K. senegalensis, has the most notable biological activities and traditional uses in the genus Khaya.

Conclusion

The present detailed and up-to-date review of recent literature on the biological activities in the genus Khaya reveals the potentials of limonoids for drug development in managing several ailments.

Occurrence, Biosynthesis, Biological activity and NMR Spectroscopy of D and B, D Ring Seco-limonoids of Meliaceae Family

Limonoids are modified tetranortriterpenoids, classified on the basis of which of the four rings (A, B, C and D) in the intact triterpene nucleus have been oxidized. The order Rutales produces a variety of seco-limonoids, such as A, B, C, D, AB, AD, and BD-ring seco-limonoids. The Meliaceae family, belonging to the order Rutales, has yielded several D-ring and B, D-ring seco-limonoids This review describes the occurrence, biosynthesis, biological activity and NMR spectroscopy of D ring seco-limonoids, such as gedunin derivatives and B, D-ring seco-limonoids, such as methyl angolensates, xyloccensins, methyl meliacates, phragmalins and modified phragmalins. The literature from 1990 to 2005 is reviewed.

Isolation, characterization and mode of action of a larvicidal compound, 22-hydroxyhopane from Adiantum latifolium Lam. against Oryctes rhinoceros Linn

Oryctes rhinoceros Linn. is one of the most serious pests of coconuts and other palms. Following bioassay guided method, a larvicidal compound, 22-hydroxyhopane has been isolated for the first time from methanol extract of leaves of Adiantum latifolium Lam. against the pest (LC₅₀ value 20.81 μg/g). It is a hopanoid triterpene with molecular mass of 442.42 g/mol. The compound exhibited antibacterial activity against symbiotic gut bacteria, caused histolysis of midgut tissues and inhibited secretion of digestive enzymes such as protease, amylase and trehalase resulting in weight loss of larvae. Enzyme immunoassay showed an elevation of 20-hydroxyecdysone level in haemolymph causing disruption of metamorphosis of larvae.

Anti-inflammatory activity of Khayandirobilide A from Khaya senegalensis via NF-κB, AP-1 and p38 MAPK/Nrf2/HO-1 signaling pathways in lipopolysaccharide-stimulated RAW 264.7 and BV-2 cells

BACKGROUND

Immunocytes-involved inflammation is considered to modulate the damage in various diseases. Herein, novel therapeutics suppressing over-activation of immunocytes could prove an effective strategy to prevent inflammation-related diseases.

PURPOSE

The objective of this study is to evaluate the anti-inflammatory activity of Khayandirobilide A (KLA), a new andirobin-type limonoid with modified furan ring isolated from the Khaya senegalensis (Desr.) A. Juss., and to explore its potential underlying mechanisms in LPS-stimulated inflammatory models.

METHODS

The structure of KLA was elucidated on the basis of 1D- and 2D-NMR spectroscopic data as well as HR-ESI-MS. As for its anti-inflammatory effect, the production of pro-inflammatory mediators and cytokines in LPS-stimulated RAW 264.7 and BV-2 cells were measured by Griess reagent, ELISA and qRT-PCR. The relevant proteins including nuclear factor κB (NF-κB), p-AKT, p-p38 and Nrf2/HO-1 were investigated by western blot. Nuclear localisations of NF-κB, activator protein-1 (AP-1) and Nrf2 were also examined by western blot and immunofluorescence.

RESULTS

KLA could inhibit the production of LPS-induced NO with IC₅₀ values of 5.04 ± 0.14 µM and 4.97 ± 0.5 µM in RAW 264.7 and BV-2 cells, respectively. KLA also attenuated interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein and mRNA levels. Further mechanistic studies demonstrated the activation of NF-κB and AP-1 were reduced by KLA. Moreover, KLA elevated expression of heme oxygenase-1(HO-1) via inducing Keap1 autophagic degradation and promoting Nrf2 nuclear translocation. Despite KLA induced the phosphorylation of mitogen-activated protein kinases (MAPKs) family, inhibiting the phosphorylation of p38 by its specific inhibitor SB203580 attenuated the degradation of KLA-induced Keap1, and then reduced KLA-induced Nrf2 nuclear translocation and HO-1 expression. Furthermore, SB203580, Brusatol (a Nrf2 specific inhibitor) and ZnPP (a HO-1 specific inhibitor) could partly reverse the suppressive effects of KLA on LPS-induced NO production and mRNA levels of pro-inflammatory genes.

CONCLUSION

These data displayed that KLA possessed anti-inflammatory activity, which was attributed to inhibit the release of LPS-stimulated inflammatory mediators via suppressing the activation of NF-κB, AP-1, and upregulating the induction of p38 MAPK/Nrf2-mediated HO-1.

Recent progress in the chemistry and biology of limonoids

Significant limonoids: new isolated limonoids, and recent developments in the total chemical synthesis, and structural modifications of limonoids regarding the bioactivities have been summarised.

Mexicanolide limonoids with in vitro neuroprotective activities from seeds of Khaya senegalensis

Fourteen new mexicanolide-type limonoids khasenegasins A–N (1–14) were isolated from the seeds of Khaya senegalensis, and bioactivity scan indicated that these mexicanolide-type limonoids displayed neuroprotective activities.

The uniqueness and therapeutic value of natural products from West African medicinal plants, part II: terpenoids, geographical distribution and drug discovery

In this review series, an attempt has been made to give indepth coverage of natural products derived from West African medicinal plants with diverse biological activities.

Rings B,D-seco limonoid antifeedants from Swietenia mahogani

Three phragmalin-type limonoids, swietephragmin H (1), swietephragmin I (2) and 11-hydroxyswietephragmin B (3), and a mexicanolide-type limonoid 2-hydroxy-6-deacetoxyswietenine (4), together with known compounds, 6-O-acetyl-2-hydroxyswietenin (5), 2-hydroxyswietenine (6), swietemahonin G (7), methyl 6-hydroxyangolensate (8) and 7-deacetoxy-7-oxogedunin (9) were isolated from the leaves of Swietenia mahogani (Meliaceae). Their structures were established by extensive NMR experiments in conjunction with mass spectrometry. The antifeedant activity of the isolated compounds was evaluated.

Khayseneganins A-H, limonoids from Khaya senegalensis

Eight new limonoids, khayseneganins A-H (1-8), and 31 known limonoids were isolated from the leaves and twigs of Khaya senegalensis. The structures of the new compounds were elucidated by 2D-NMR spectroscopy and mass spectrometry, and the absolute configuration of 1 was determined by the CD exciton chirality method. Compounds 9, 10, 12, and 15 showed antimicrobial activities against Pseudomonas aeruginosa, MRSA 92(#), and MRSA 98(#), all with a MIC value of 12.5 μg/mL.

Ring A-seco limonoids and flavonoids from the Kenyan Vepris uguenensis Engl. and their antioxidant activity

Two A-seco-limonoids, accorded the trivial names, uguenensene and uguenensone and a C-7 prenylated flavonoid, uguenenprenol were isolated from Vepris uguenensis (Rutaceae). In addition, 11 known compounds, niloticin, chisocheton A, kihadalactone A, limonyl acetate, methyl uguenenoate, 7-O-methylaromadenrin, flindersiamine, 8α,11-elemodiol, tricoccin S₁₃ acetate, skimmianine, and lupeol were isolated. The structures of the compounds were elucidated and characterized by spectroscopic analyses (NMR, GC-MS and IR). Antioxidant activity of the isolated compounds showed that uguenenprenol and 7-O-methylaromadenrin are good antioxidant agents. Significantly high antioxidant activity was also exhibited by 8α,11-elemodiol, which was 72% at 250 μg mL⁻¹ and 57% at 15.62 μg mL⁻¹ when tested with the deoxyribose method. The two liminoids fit nicely into the biosynthetic pathway from niloticin to methyl uguenenoate.

Limonoids and triterpenoids from Khaya senegalensis

Seven new limonoids (1-7), named khayalenoids C-I, three new triterpenoids (8-10), named senegalenes A-C, and eight known limonoids have been isolated from stems of Khaya senegalensis. The structures of these compounds were elucidated on the basis of spectroscopic analyses.

Limonoids from Khaya ivorensis

Four limonoids, 1-O-deacetyl-6-deoxykhayanolide E (1), 1-O-deacetyl-2 alpha-hydroxykhayanolide E (2), 3-acetyl-khayalactone (3), 11 alpha-acetoxy-2 alpha-hydroxy-6-deoxy-destigloylswietenine acetate (4), along with 12 known limonoids, were isolated from the stems of Khaya ivorensis. Their structures were elucidated on the basis of spectroscopic analysis.

Khayanolides from African mahogany Khaya senegalensis (Meliaceae): A revision

Five khayanolides (1-O-acetylkhayanolide B 1, khayanolide B 2, khayanolide E 3, 1-O-deacetylkhayanolide E 4, 6-dehydroxylkhayanolide E 5) were isolated from the stem bark of African mahogany Khaya senegalensis (Meliaceae). Their structures and absolute configurations were determined through extensive spectroscopic analyses including MS, NMR, and single-crystal X-ray diffraction experiments. The results established that two previously reported khayanolides, 1alpha-acetoxy-2beta,3alpha,6,8alpha,14beta-pentahydroxy-[4.2.1(10,30).1(1,4)]-tricyclomeliac-7-oate 6 and 1alpha,2beta,3alpha,6,8alpha,14beta-hexahydroxy-[4.2.1(10,30).1(1,4)]-tricyclomeliac-7-oate 7, were, in fact, 1-O-acetylkhayanolide B 1 and khayanolide B 2, and that the two reported phragmalin derivatives, methyl 1alpha-acetoxy-6,8alpha,14beta,30beta-tetrahydroxy-3-oxo-[3.3.1(10,2).1(1,4)]-tricyclomeliac-7-oate 8 and methyl 1alpha,6,8alpha,14beta,30beta-pentahydroxy-3-oxo-[3.3.1(10,2).1(1,4)]-tricyclomeliac-7-oate 9, were, in fact, khayanolide E 3 and 1-O-deacetylkhayanolide E 4, respectively. Based on the results from this study and consideration of the biogenetic pathway, the methyl 6-hydroxyangolensate in African mahogany K. senegalensis should have a C-6 S configuration while methyl 6-hydroxyangolensate in genuine mahogany Swietenia species should have a C-6 R configuration.

Limonoids from the stem bark of Cedrela odorata

Four nomilin/obacunol derivatives and a swietenolide derivative, together with seven known limonoids, were isolated from stem bark of Cedrela odorata and their structures established by spectroscopic methods. Antifeedant activity of the isolated compounds was also tested.

Limonoids: overview of significant bioactive triterpenes distributed in plants kingdom

The search for limonoids started long back when scientists started looking for the factor responsible for bitterness in citrus which has negative impact on citrus fruit and juice industry worldwide. The term limonoids was derived from limonin, the first tetranortriterpenoid obtained from citrus bitter principles. Compounds belonging to this group have exhibited a range of biological activities like insecticidal, insect antifeedant and growth regulating activity on insects as well as antibacterial, antifungal, antimalarial, anticancer, antiviral and a number of other pharmacological activities on humans. Although hundreds of limonoids have been isolated from various plants but, their occurrence in the plant kingdom is confined to only plant families of order Rutales and that too more abundantly in Meliaceae and Rutaceae, and less frequently in Cneoraceae and Harrisonia sp. of Simaroubaceae. Limonoids are highly oxygenated, modified terpenoids with a prototypical structure either containing or derived from a precursor with a 4,4,8-trimethyl-17-furanylsteroid skeleton. All naturally occurring citrus limonoids contain a furan ring attached to the D-ring, at C-17, as well as oxygen containing functional groups at C-3, C-4, C-7, C-16 and C-17. The structural variations of limonoids found in Rutaceae are less than in Meliaceae and are generally limited to the modification of A and B rings, the limonoids of Meliaceae are more complex with very high degree of oxidation and rearrangement exhibited in the parent limonoid structure. To counter the problem of bitterness in citrus juice and products genetic engineering of citrus to maximize the formation of limonoid glucosides for reducing limonoid bitterness is the focus of recent and future research. Regarding the biological activities of limonoids the investigations are to be directed towards detailed characterization, quantification, and designing a simple as well as versatile synthetic route of apparently important limonoids. Extraction methods too should be optimized; evaluation and establishment of pharmaco-dynamic and kinetic principles, and structure activity relationships should be a key goal associated with limonoids so that they can be safely introduced in our arsenal of pharmaceuticals to safeguard the humanity from the wrath of disease and its discomfort.

Four tetranortriterpenoids from the stem bark of Khaya anthotheca

Eight limonoids, anthothecanolide (1), 3-O-acetylanthothecanolide (2), 2,3-di-O-acetylanthothecanolide (3), 6R,8alpha-dihydroxycarapin (4), 3beta-acetoxy-3-deoxo-6R-hydroxycarapin (5), methyl angolensate, methyl 6-hydroxyangolensate and khayalactone together with sitosterol glucoside, have been isolated from the extracts of the stem bark of Khaya anthotheca. Compounds 1-4 are described for the first time. Their structures were established by analysis of the high-field NMR and MS data. The structure of compound 4 was confirmed by a single crystal X-ray structure analysis.

Antifungal activity of limonoids from Khaya ivorensis

Chemical investigation of the diethyl ether extract of the stem bark of Khaya ivorensis A Chev (Meliaceae) afforded ten limonoids of angolensates, ring D-opened limonoids and mexicanolides. The structures of the limonoids isolated were determined by comparison of their (1)H and (13)C NMR data with those reported in the literature. These compounds were evaluated for their antifungal activity against the plant pathogenic fungus Botrytis cinerea Pers. Methyl 6-hydroxyangolensate and 3,7-dideacetylkhivorin were also tested for their antifungal and antibacterial activities on several fungal and bacterial species. Methyl angolensate and 1,3,7-trideacetylkhivorin displayed the highest antifungal activity against B. cinerea, with respectively 62.8 and 64.0% mycelial growth inhibition at 1000 mg litre(-1), and 73.3 and 68.6% mycelial growth inhibition at 1500 mg litre(-1). 3,7-Dideacetylkhivorin showed stronger antifungal and antibacterial activities than methyl 6-hydroxyangolensate against all of the test fungi and bacteria except Penicillium expansum Link. This is the first report on the antifungal and antibacterial effects of these limonoids. Structure-antifungal activity relationships of the limonoids isolated are discussed.

Phragmalin limonoids from Chukrasia tabularis

Six phragmalin limonoids, named tabulalin and tabulalides A-E, were isolated from the root bark of Chukrasia tabularis (Meliaceae). Their structures were determined by spectroscopic methods, and their antifeedant properties evaluated.

Antifungal limonoids from the fruits of Khaya senegalensis

Investigation of the fruits of Khaya senegalensis resulted in the isolation of three new mexicanolide limonoids containing a rare conjugated diene lactone system named seneganolide A (1), 2-hydroxyseneganolide A (2) and 2-acetoxyseneganolide A (3). Two known limonoids, 3-deacetyl-7-deacetoxy-7-oxokhivorin (4) and methyl 6-hydroxyangolensate (5), were also found. The structures of the new compounds were elucidated on the basis of spectral methods. The antifungal activity of compounds 1, 3 and 5 was tested against the fungus Botrytis cinerea.

Xyloccensins O and P, Unique 8,9,30-Phragmalin Ortho Esters from Xylocarpus granatum

Two unique 8,9,30-phragmalin ortho esters, xyloccensins O (1) and P (2), were isolated from the mangrove plant Xylocarpus granatum. They are a new type of ortho ester of phragmalin. The structures were determined by spectroscopic and single-crystal X-ray diffraction techniques. The biogenetic pathway to these new phragmalins was also proposed. [structure: see text]

Advantages of soxflo extractions for phytochemical analysis and bioassay screening. 1. Terpenoids

The Soxflo technique was evaluated for the rapid extraction of plant materials (<90 min) at room temperature. Qualitatively similar chromatograms were obtained by gas chromatography and thin layer chromatography (TLC) with Soxflo (SoF) and Soxhlet (SoL) extracts. Sequential solvent extractions by SoF gave slightly higher yields (132%) of five major sesquiterpenoids. TLC revealed that SoF extractions at room temperature were more selective as extracts contained compounds with a narrower range of R(f)() values. This means that the SoF technique offers the potential for one-step extractions and partial fractionation. This study also showed that there were large differences in the volatile composition of dried and fresh Piper fruits: dried fruits had predominantly sesquiterpenoids while fresh fruits had considerable quantities of both mono- and sesquiterpenoids. This is the first report of alpha-guaiene and alpha- and beta-selinene in Piper guineense fruits. It is suggested that the SoF technique can be useful for the screening of large numbers of plants for phytochemicals or for the preparation of plant extracts for subsequent bioassay studies.

Three new modified limonoids from Khaya senegalensis

Three new rings B/D opened limonoids, two rearranged phragmalin limonoids named khayanolides D and E (1 and 2), and one limonoid glucoside named khayanoside (3) were isolated as insect antifeedants from the stem bark of Egyptian Khaya senegalensis. The structures of these compounds were established by spectroscopic methods, including 2D NMR and CD.