Carapanolides C–I from the seeds of andiroba (Carapa guianensis, Meliaceae)

Hainanxylogranolides A-F: New Limonoids isolated from the seeds of Hainan mangrove plant Xylocarpus granatum

Six new limonoids, named hainanxylogranolides A-F (1-6), together with nineteen known ones (7-25) were isolated from the seeds of a Hainan mangrove Xylocarpus granatum. The structures of the new compounds were established by extensive NMR spectroscopic data combined with the DFT and TDDFT calculated electronic circular dichroism spectra. Hainanxylogranolide A (1) is the aromatic B-ring limonoid containing a central pyridine ring and a C-17 substituted γ(21)-hydroxybutenolide moiety. Hainanxylogranolide B (2) belongs to the small group of mexicanolides containing a C₃-O-C₈ bridge, whereas hainanxylogranolides C and D (3 and 4) are mexicanolides comprising a C₁-O-C₈ bridge. Compounds 9 and 25 posed obvious inhibition effect on the tube formation of HUVECs. There are only about 25% tube-like structures were observed at the concentration of 40.0 μM of compound 25. The antiviral activities of the isolates against herpes simplex virus-1 (HSV-1) and severe fever with thrombocytopenia syndrome virus (SFTSV) were tested in vitro. Compound 23 exhibited moderate anti-SFTSV activity with the IC₅₀ value of 29.58 ± 0.73 μM. This is the first report of anti-angiogenic effect and anti-SFTSV activity of limonoids from the genus Xylocarpus.

Bioactive limonoids from Carapa guianensis seeds oil and the sustainable use of its by-products

Carapa guianensis (Andiroba, Meliaceae) is considered a multipurpose tree. In Brazil, Indigenous people have used it as insect repellent and in the treatment of various diseases. Most biological activities and popular uses are attributed to limonoids, which are highly oxygenated tetranortriterpenoids. More than 300 limonoids have been described in Meliaceae family. Limonoids from Andiroba oil have shown high anti-inflammatory and anti-allergic activities in vivo, by inhibiting platelet activating factors and many inflammatory mediators such as IL-5, IL-1β and TNF-α. It also reduced T lymphocytes, eosinophils and mast cells. In corroboration with the wide popular use of Andiroba oil, no significant cytotoxicity or genotoxicity in vivo was reported. This oil promotes apoptosis in a gastric cancer cell line (ACP02) at high concentrations, without showing mutagenic effects, and is suggested to increase the body's nonspecific resistance and adaptive capacity to stressors, exhibit some antioxidant activity, and protect against oxidative DNA damages. Recently, new methodologies of toxicological assays have been applied. They include in chemico, in vitro, in silico and ex vivo procedures, and take place to substitute the use of laboratory animals. Andiroba by-products have been used in sustainable oil production processes and as fertilizers and soil conditioners, raw material for soap production, biodegradable surfactants and an alternative natural source of biodegradable polymer in order to reduce environmental impacts. This review reinforces the relevance of Andiroba and highlights its ability to add value to its by-products and to minimize possible risks to the health of the Amazonian population.

Research progress of meliaceous limonoids from 2011 to 2021

Covering: July 2010 to December 2021Limonoids, a kind of natural tetranortriterpenoids with diverse skeletons and valuable insecticidal and medicinal bioactivities, are the characteristic metabolites of most plants of the Meliaceae family. The chemistry and bioactivities of meliaceous limonoids are a continuing hot area of natural products research; to date, about 2700 meliaceous limonoids have been identified. In particular, more than 1600, including thirty kinds of novel rearranged skeletons, have been isolated and identified in the past decade due to their wide distribution and abundant content in Meliaceae plants and active biosynthetic pathways. In addition to the discovery of new structures, many positive medicinal bioactivities of meliaceous limonoids have been investigated, and extensive achievements regarding the chemical and biological synthesis have been made. This review summarizes the recent research progress in the discovery of new structures, medicinal and agricultural bioactivities, and chem/biosynthesis of limonoids from the plants of the Meliaceae family during the past decade, with an emphasis on the discovery of limonoids with novel skeletons, the medicinal bioactivities and mechanisms, and chemical synthesis. The structures, origins, and bioactivities of other new limonoids were provided as ESI. Studies published from July 2010 to December 2021 are reviewed, and 482 references are cited.

New cytotoxic obacunone-type limonoid and others constituents from the stem bark of Carapa procera DC (Meliaceae)

The phytochemical study of the CH₂Cl₂- MeOH (1:1, v/v) extract of the stem bark of Carapa procera DC (Meliaceae) led to the isolation and characterisation of a new natural limonoid 7β-obacunol (6), along with seven known compounds. Their structures were elucidated by spectroscopic means, including 1 D and 2 D NMR, HRESI-MS and by comparison with published data. The cytotoxicity of compounds 1-6 was assessed in vitro by the WST-1 assay on human lung adenocarcinoma A549 and Raw 264.7 mouse macrophage cell lines. Results suggested that obacunone (3) exhibited the most potent cytotoxic effect against A549 and Raw 264.7 cells with respective IC₅₀ values of 25.24 µM and 29.14 µM, while the new natural limonoid 7β-obacunol (6) exhibited 32.75 µM and 39.19 µM, respectively on both cell lines. Therefore, limonoid derivatives might be promising sources of natural bioactive metabolites against cancer.

Triterpenoids

Covering 2014. Previous review: Nat. Prod. Rep., 2017, 34, 90-122 This review covers the isolation and structure determination of triterpenoids reported during 2014 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 374 references are cited.

Carapa guianensis Aublet (Andiroba) Seed Oil: Chemical Composition and Antileishmanial Activity of Limonoid-Rich Fractions

Leishmaniasis is a complex of diseases caused by protozoa of the genus Leishmania and affects millions of people around the world. Several species of plants are used by traditional communities for the treatment of this disease, among which is Carapa guianensis Aubl. (Meliaceae), popularly known as andiroba. The objective of the present work was to conduct a chemical study of C. guianensis seed oil and its limonoid-rich fractions, with the aim of identifying its secondary metabolites, particularly the limonoids, in addition to investigating its anti-Leishmania potential. The chemical analyses of the C. guianensis seed oil and fractions were obtained by electrospray ionization mass spectrometry (ESI-MS). The cytotoxic activity was tested against peritoneal macrophages, and antileishmanial activity was evaluated against promastigotes and intracellular amastigotes of Leishmania amazonensis. All the C. guianensis seed oil samples analyzed exhibited the same pattern of fatty acids, while the limonoids 7-deacetoxy-7-hydroxygedunin, deacetyldihydrogedunin, deoxygedunin, andirobin, gedunin, 11β-hydroxygedunin, 17-glycolyldeoxygedunin, 6α-acetoxygedunin, and 6α,11β-diacetoxygedunin were identified in the limonoid-rich fractions of the oil. The C. guianensis seed oil did not exhibit antileishmanial activity, and cytotoxicity was higher than 1000 μg/mL. Three limonoid-rich oil fractions demonstrated activity against promastigotes (IC50 of 10.53±0.050, 25.3±0.057, and 56.9±0.043μg/mL) and intracellular amastigotes (IC50 of 27.31±0.091, 78.42±0.086, and 352.2±0.145 μg/mL) of L. amazonensis, as well as cytotoxicity against peritoneal macrophages (CC50 of 78.55±1.406, 139.0±1.523, and 607.7±1.217 μg/mL). The anti-Leishmania activity of the limonoid-rich fractions of C. guianensis can be attributed to the limonoids 11β-hydroxygedunin and 6α,11β-diacetoxygedunin detected in the chemical analysis.

Carapanosins D-F from the Seeds of Andiroba (Carapa guianensis, Meliaceae) and Their Effects on LPS-Activated NO Production

A novel nor-phragmalin-type limonoid, named carapanosin D (1), and two novel mexicanolide-type limonoids, carapanosins E (2) and F (3), were isolated from the seed oil of andiroba (Carapa guianensis A_ublet), a traditional medicine in Brazil and Latin American countries. Their structures were unambiguously determined on the basis of spectroscopic analyses using one-dimensional (1D) and two-dimensional (2D) NMR techniques and High resolution Fast Atom Bombardment Mass Spectrometry (HRFABMS). Compounds 1–3 were evaluated for their effects on the production of nitric oxide (NO) in Lipopolysaccharide (LPS)-activated mouse peritoneal macrophages. The NO inhibitory assay suggested that compounds 2 and 3 have high potency as inhibitors of macrophage activation.

Carapanosins A-C from Seeds of Andiroba (Carapa guianensis, Meliaceae) and Their Effects on LPS-Activated NO Production

Two new phragmalin-type limonoids, Carapanosins A and B (1 and 2), and a new gedunin-type limonoid, Carapansin C (3), together with five known limonoids (4–8) were isolated from the oil of Carapa guianensis A_UBLET (Meliaceae) seeds, a traditional medicine in Brazil and Latin American countries. Their structures were elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques and HRFABMS. Compounds 1–8 were evaluated for their effects on the production of NO in LPS-activated mouse peritoneal macrophages. The NO inhibitory assay suggested that Compounds 3, 6, and 8 may be valuable as potential inhibitors of macrophage activation.

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.

Hepatoprotective Limonoids from Andiroba (Carapa guianensis)

Three gedunin-type limonoids, gedunin (1), 6α-acetoxygedunin (2), and 7-deacetoxy-7-oxogedunin (3), which were isolated from the seed and flower oils of andiroba (Carapa guianensis Aublet, Meliaceae), exhibited hepatoprotective effects at doses of 25 mg/kg, p.o. against d-galactosamine (d-GalN)/lipopolysaccharide (LPS)-induced liver injury in mice. To characterize the mechanisms of action of 1-3 and clarify the structural requirements for their hepatoprotective effects, 17 related limonoids (1-17) isolated from the seed and/or flower oils of C. guianensis were examined in in vitro studies assessing their effects on (i) d-GalN-induced cytotoxicity in primary cultured mouse hepatocytes, (ii) LPS-induced nitric oxide (NO) production in mouse peritoneal macrophages, and (iii) tumor necrosis factor-α (TNF-α)-induced cytotoxicity in L929 cells. The mechanisms of action of 1-3 are likely to involve the inhibition of LPS-induced macrophage activation and reduced sensitivity of hepatocytes to TNF-α; however, these compounds did not decrease the cytotoxicity caused by d-GalN. In addition, the structural requirements of limonoids (1-17) for inhibition of LPS-induced NO production in mouse peritoneal macrophages and TNF-α-induced cytotoxicity in L929 cells were evaluated.

Carapanolides T-X from Carapa guianensis (Andiroba) Seeds

Two new mexicanolide-type limonoids, carapanolides T–U (1–2), and three new phragmalin-type limonoids, carapanolides V–X (3–5), were isolated from the seeds of Carapa guianensis (andiroba). Their structures were determined on the basis of 1D- and 2D-NMR spectroscopy.

Carapanolides J-L from the seeds of Carapa guianensis (Andiroba) and their effects on LPS-activated NO production

A novel gedunin and two novel phragmalin-type limonoids, named carapanolides J–L (compounds 1–3) as well as a known gedunin-type limonoid 4 were isolated from the seeds of Carapa guianensis (andiroba). Their structures were determined on the basis of 1D and 2D NMR spectroscopy and HRFABMS. Compounds 1–4 were evaluated for their effects on the production of NO in LPS-activated mouse peritoneal macrophages.

Andirolides W-Y from the flower oil of andiroba (Carapa guianensis, Meliaceae)

Three new limonoids, andirolides W-Y (1-3), were isolated from the flower oil of Carapa guianasis AUBLET (Meliaceae). Their structures were elucidated on the basis of spectroscopic analyses using 1D and 2D NMR spectra and FABMS. Seven known limonoids: 7-deacetoxy-7-oxogedunin (4), 6α-acetoxygedunin (5), methylangolensate (6), 6α-hydroxygedunin (7), 6α-acetoxy-7α-deacetoxy-7α-hydroxygedunin (8), gedunin (9), and 7-deacetoxy-7-hydroxygedunin (10) from this flower oil were evaluated for the effects on the production of NO in LPS-activated mouse peritoneal macrophages.