Limonoids from the seeds of a Godavari mangrove, Xylocarpus moluccensis

Ten limonoids, named godavarins A-J (1-7, 9-11), were isolated from seeds of an Indian mangrove (Xylocarpus moluccensis) collected in the mangrove wetlands of Godavari estuary, Andhra Pradesh. Eight known limonoids, viz. xyloccensins L (8), P (12), Q (13), mexicanolide (14), 6-deoxy-3-detigloyl-swietenine acetate (15), fissinolide (16), methyl 3β-acetoxy-1-oxomeliaca-8(30),14-dienoate (17), and methyl 3β-acetoxy-1-oxomeliaca-8(9),14-dienoate (18), were also obtained. The structures of these compounds were established on the basis of spectroscopic data or comparison with data in the literature (known compounds). The stereostructure of godavarin D was confirmed by means of single-crystal X-ray analysis. Godavarins A-C are the first mexicanolide derivatives with a C₇-C₂₈ ester-linked δ-lactone ring, while godavarins D-G are further additions to the small group of limonoids with a C₁-C₂₉ oxygen bridge. Godavarin H is a phragmalin with five acetoxy groups. Two limonoids, mexicanolide and fissinolide, were found to exhibit marked antifeedant activity against the third-instar larvae of Brontispa longissima (Gestro) at a concentration of 0.5 mg/mL. The most potent compound was mexicanolide. It also showed moderate insecticidal activity.     

Limonoids and triterpenoids from the seed of Neobeguea mahafalensis

Three triterpenoids, sapelin C, sapelin E acetate and grandifoliolenone, were isolated from the hexane extract of the seed shells of Neobegueae mahafalensis (Meliaceae). The ethyl extract of the seed yielded the known limonoids, methyl angolensate, mexicanolide and khayasin.     

Structural elucidation of limonoids and steroids from Trichilia connaroides

Six limonoids, trijugins D-H (1-5) and methyl 8alpha-hydroxy-8,30-dihydroangolensate (6), two degraded limonoids, trichiconnarins A and B (7-8), and a pregnane steroid, 3beta,4alpha-dihydroxypregnan-21-one (9), along with the known trijugin C (10) and 3beta,4alpha-dihydroxypregnan-16-one (11) were isolated from twigs and leaves of Trichilia connaroides. Their structures were established on the basis of extensive spectroscopic analysis.     

Limonoids with an Oxygen Bridge between C(1) and C(29) from the Seeds of a Krishna Mangrove,Xylocarpus granatum

Ten limonoids, named granatumins L–U ( 1 – 10 , resp.), were isolated from the seeds of an Indian mangrove, Xylocarpus granatum, collected in the estuary of Krishna, Andhra Pradesh. The structures of these compounds were established on the basis of spectroscopic data. The relative configuration of granatumin L ( 1 ) was confirmed by a single‐crystal X‐ray diffraction analysis. Granatumins L–T ( 1 – 9 , resp.) belong to the small group of limonoids with an oxygen bridge between C(1) and C(29), while granatumin U ( 10 ) is a 28‐Me‐oxidized mexicanolide. This is the first report of limonoids with an O‐bridge between C(1) and C(29) from the Indian X. granatum. The pronounced structural diversity of limonoids from this mangrove might originate from environmental factors.     

Rings B,D-seco limonoids from the leaves of Swietenia mahogani

Seven phragmalin limonoids of swietephragmins A-G, and two other different types of 2-hydroxy-3-O-tigloylswietenolide and deacetylsecomahoganin, were isolated along with three known limonoids from the leaves of Swietenia mahogani (Meliaceae). Their structures were determined by spectroscopic methods.     

Limonoids from the stems of Toona ciliata var. henryi (Meliaceae)

Ten limonoids, toonacilianins A-J, and two norlimonoids, toonacilianins K and L, together with seven known compounds were isolated from the stems of Toona ciliata var. henryi (Meliaceae). Their structures were elucidated by spectroscopic analysis. Two compounds showed strong cytotoxic activities.     

Limonoids from Turraea floribunda (Meliaceae)

Six novel limonoids and limonoid derivatives, turraflorins D-I along with the known turraflorins A and B have been isolated from seed of the South African Turraea floribunda (Meliaceae).     

Limonoids from Cedrela sinensis

Five limonoids were isolated from the leaves of Cedrela sinensis (Meliaceae) and their structures were determined to be 11beta-hydroxy-7alpha-obacunyl acetate, 11-oxo-7alpha-obacunyl acetate, 11-oxo-7alpha-obacunol, 11beta-hydroxycneorin G, and 11-oxocneorin G, by 2D NMR spectroscopic experiments, X-ray crystallographic analysis, and chemical methods.     

Cyclopropane- and spirolimonoids and related compounds from Hortia oreadica

The dichloromethane extract from taproots of Hortia oreadica afforded six limonoids, these are 9,11-dehydro-12α-acetoxyhortiolide A, hortiolide C, 11α-acetoxy-15-deoxy-6-hydroxyhortiolide C, hortiolide D, hortiolide E, 12β-hydroxyhortiolide E, in addition to the known limonoid, guyanin. The dichloromethane extract from stems of H. oreadica also afforded two limonoids 9,11-dehydro-12α-hydroxyhortiolide A and 6-hydroxyhortiolide C. As a result of this study and literature data, Hortia has been shown to produce highly specialized limonoids that are similar to those from the Flindersia (Flindersioideae). The taxonomy of Hortia has been debatable, with most authors placing it in the Toddalioideae. Considering the complexity of the isolated limonoids, Hortia does not show any close affinity to the genera of Toddalioideae. That is, the limonoids appear to be of little value in resolving the taxonomic situation of Hortia.     

Diterpenes and sesquiterpenes from the bark of Taxus yunnanensis

Two taxane-type diterpenes, 10beta-acetoxy-2alpha,5alpha,7beta,9alpha-tetrahydroxytaxa-4(20),11-dien-13-one and 2alpha-acetoxy-9alpha-benzoyloxy-5alpha,7beta,10beta,15-tetrahydroxy-11(15-->1)- abeotaxa-4(20),11-dien-13-one, and two new drimane-type sesquiterpenes, 1beta-acetoxy-7-drimen-11alpha-ol-12,11-lactone and 1beta-acetoxy-11,12-epoxy-6-drimen-8alpha,11alpha-diol, were isolated from the bark of Taxus yunnanensis together with 35 known taxane-type diterpenes, a known drimane-type sesquiterpene and a known flavanone.     

Phragmalin-type limonoids with NF-κB inhibition from Chukrasia tabularis var. velutina

Chemical investigation on Chukrasia tabularis var. velutina led to the identification of eight new phragmalin-type limonoids (1–8), as well as 20 known analogues. Compounds 1–4 are a rare class of C-15-acyl phragmalin-type limonoids, and particularly compounds 2–4 also possess a δ-lactone ring formed between C-16 and C-30. All the isolates were evaluated for inhibitory effects on NF-κB production, and four of which showed significant inhibitions.     

Alkaloids and limonoids from Bouchardatia neurococca: systematic significance

Five alkaloids, four beta-indoloquinazoline and one furoquinoline, and four terpenoids, three limonoids and one modified sesquiterpene, have been obtained from the aerial parts of Bouchardatia neurococca (Rutaceae). Two of the alkaloids, 1,2-dihydroxyrutaecarpine and 2-(2-[3-formylindolyl])-(3H)-quinazolin-4-one (bouchardatine), and two of the limonoids, 23-oxo-21xi-hydroxy-21,23-dihydroveprisone (veprisonic acid) and 21-oxo-23xi-hydroxy-21,23-dihydroveprisone (isoveprisonic acid) are new. The pattern of secondary metabolites isolated is rather unusual in the Rutaceae and is reminiscent of Tetradium, a genus with which Bouchardatia has not previously been associated.     

Limonoids from the stem bark of Khaya grandifoliola

Three limonoids, deacetylkhayanolide E (1), 6S-hydroxykhayalactone (2), and grandifolide A (3), along with three known ones, were isolated from stem bark of the Nigerian medicinal plant Khaya grandifoliola. Their structures were characterized on the basis of the application of spectroscopic methods. In vitro antimicrobial and cytotoxic activities of the isolates were also tested, but were all found to be inactive.     

Limonoids from the seed of the natal mahogany, Trichilia dregeana

We have investigated the seed limonoids of Trichilia dregeana and obtained the known rohituka-7, an ester related to polystachin, and four new compounds designated dregeana-1 to 4. These were found to be intermediate in oxidation level between rohituka-7 and heudelottin.     

Limonoids from seeds of Thai Xylocarpus moluccensis

A new andirobin, thaimoluccensin A (1), and two new phragmalin-type limonoids, thaimoluccensins B (2) and C (3), were isolated from seeds of a Thai mangrove plant, Xylocarpus moluccensis, together with eight known compounds. The structures of these compounds were elucidated on the basis of spectroscopic data. Only 7-deacetylgedunin (7), a gedunin-type limonoid, exhibited significant inhibitory activity against nitric oxide production from activated macrophages with IC₅₀ value less than 10 μM, suggesting that the compound has anti-inflammatory activity.     

4alpha-methyl-24beta-ethyl-5alpha-cholesta-14,25-dien-3beta-ol and 24beta-ethylcholesta-5, 9(11), 22E-trien-3beta-ol,sterols from Clerodendrum inerme

From the aerial parts of Clerodendrum inerme, two new sterols (4alpha-methyl-24beta-ethyl-5alpha-cholesta-14, 25-dien-3beta-ol and 24beta-ethylcholesta-5, 9(11), 22E-trien-3beta-ol) and a new aliphatic ketone (11-pentacosanone) were isolated together with another known aliphatic ketone (6-nonacosanone) and a diterpene (clerodermic acid). The structure elucidations were based on analyses of physical and spectroscopic data.     

Identifying citrus limonoid aglycones by HPLC-EI/MS and HPLC-APCI/MS techniques

HPLC coupled with normal phase electron ionisation (EI) and atmospheric pressure chemical ionisation (APCI)/ mass spectrometry methods has been applied to identify 17 known neutral limonoid aglycones from Citrus sources. The HPLC-MS data from the known limonoids provided chromatographic characteristics, APCI-derived molecular weight data and EI fragmentation data for each limonoid. EI fragmentation patterns for the limonoids were correlated with structural characteristics. The EI fragmentation patterns coupled with APCI-derived molecular weights were utilised as a potential method by which to discern the structural character of unknown citrus limonoids.     

Limonoids from Khaya ivorensis

Four limonoids, 1-O-deacetyl-6-deoxykhayanolide E (1), 1-O-deacetyl-2α-hydroxykhayanolide E (2), 3-acetyl-khayalactone (3), 11α-acetoxy-2α-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.     

Characterization of Limonoids Isolated from the Fruits of Melia toosendan and Their Antifeedant Activity against Pieris rapae

The fruits of Melia toosendan Sieb . et Zucc . (Meliaceae) are a source of bioactive limonoids that can be used as effective pesticides. In this study, two novel limonoids, 6‐acetylsendanal and 6‐ketocinamodiol, were isolated together with fourteen known compounds, namely four protolimonoids, six trichilin‐class limonoids, and four C‐seco limonoids. The structures of the new compounds were determined by extensive spectroscopic analyses (HR‐ESI‐MS, UV, IR, 1D and 2D NMR). The bioassay results revealed that eleven of the extracted limonoids exhibited interesting antifeedant activities against the larvae of Pieris rapae with AFC₅₀ values in the range of 0.11–1.79 mm . Particularly, mesendanin H, with an AFC₅₀ value of 0.11 mm , exhibited a higher activity than the positive control toosendanin. Information on new bioactive limonoids may provide further insight into M. toosendan as a source of bioactive components.     

Ring A rearranged limonoids from the fruits of Aphanamixis grandifolia and their cytotoxicity evaluation

Two new limonoids aphanamolides C (1) and D (2), together with two known limonoids aphanamolide A (3) and aphapolynin A (4), were isolated from the fruits of Aphanamixis grandifolia. Their structures were assigned on the basis of spectroscopic data, with the absolute configurations of 1 and 2 being established by electronic circular dichroism (ECD) spectroscopic analyses. Those limonoids varied in the ring A: aphanamolide C featured two oxygenated bridges, and aphanamolide D was the second example containing β-hydroxy-α,β:γ,δ-dienoate moiety. The cytotoxic activities were also evaluated in vitro against four human cancer cell lines (MCF-7, A549, SMMC-7721, and HL-60).