Caesalminaxins O-T, cassane diterpenoids from the seeds of Caesalpinia minax and their anti-inflammation

Structurally diverse diterpenoids from the seeds of Caesalpinia minax Hance and their bioactivities

Eight previously undescribed diterpenoids, caesamins A-H (1-8), were separated and identified from the seeds of Caesalpinia minax Hance. Their structures were characterized by extensive spectroscopic data and X-ray crystallographic analysis. Structurally, caesamin A (1) is the first cassane-type diterpenoid with a C23 carbon skeleton containing an unusual isopropyl. Caesamin F (6) represents the first example of cleistanthane diterpenoid from the genus Caesalpinia. Caesamins B (2) and F (6) exhibited inhibitory activity against LPS-induced nitric oxide production in RAW 264.7 macrophages with IC50 values of 45.67 ± 0.92 and 42.99 ± 0.24 μM, comparable to positive control 43.69 ± 2.62 μM of NG-Monomethyl-L-arginine. Furthermore, the chemotaxonomic significance of the isolates was discussed.

Novel 6/7/6 ring system diterpenoids and cytochalasins from the fungus Eutypella scoparia GZU-4-19Y and their anti-inflammatory activity

Two new compounds eutyditerpenoid A (1) and seco-phenochalasin B (5), together with seven known compounds diaporthein A (2), aspergillon A (3), phenochalasin B (4), cytochalasins Z24 and Z25 (6 and 7), scoparasins A and B (8 and 9) were isolated from marine-derived Eutypella scoparia GZU-4-19Y. Among them, eutyditerpenoid A (1) with a rare 6/7/6 ring system possesing an anhydride moiety was the first example in the pimarane-type diterpenoids. Their structures were determined based on spectroscopic methods and the electronic circular dichroism (ECD) calculations. In the bioassays, all of the isolates were evaluated for their inhibitory activity against NO production induced by lipopolysaccharide in RAW 264.7 cells. Compounds 3 and 7 showed potent NO inhibition activity with IC50 values of 2.1 and 17.1 μM respectively, and the former also significantly suppressed the protein expression of iNOS and COX-2 at the concentration of 2.5 μM.

The dual face of microglia (M1/M2) as a potential target in the protective effect of nutraceuticals against neurodegenerative diseases

The pathophysiology of different neurodegenerative illnesses is significantly influenced by the polarization regulation of microglia and macrophages. Traditional classifications of macrophage phenotypes include the pro-inflammatory M1 and the anti-inflammatory M2 phenotypes. Numerous studies demonstrated dynamic non-coding RNA modifications, which are catalyzed by microglia-induced neuroinflammation. Different nutraceuticals focus on the polarization of M1/M2 phenotypes of microglia and macrophages, offering a potent defense against neurodegeneration. Caeminaxin A, curcumin, aromatic-turmerone, myricetin, aurantiamide, 3,6'-disinapoylsucrose, and resveratrol reduced M1 microglial inflammatory markers while increased M2 indicators in Alzheimer's disease. Amyloid beta-induced microglial M1 activation was suppressed by andrographolide, sulforaphane, triptolide, xanthoceraside, piperlongumine, and novel plant extracts which also prevented microglia-mediated necroptosis and apoptosis. Asarone, galangin, baicalein, and a-mangostin reduced oxidative stress and pro-inflammatory cytokines, such as interleukin (IL)-1, IL-6, and tumor necrosis factor-alpha in M1-activated microglia in Parkinson's disease. Additionally, myrcene, icariin, and tenuigenin prevented the nod-like receptor family pyrin domain-containing 3 inflammasome and microglial neurotoxicity, while a-cyperone, citronellol, nobiletin, and taurine prevented NADPH oxidase 2 and nuclear factor kappa B activation. Furthermore, other nutraceuticals like plantamajoside, swertiamarin, urolithin A, kurarinone, Daphne genkwa flower, and Boswellia serrata extracts showed promising neuroprotection in treating Parkinson's disease. In Huntington's disease, elderberry, curcumin, iresine celosia, Schisandra chinensis, gintonin, and pomiferin showed promising results against microglial activation and improved patient symptoms. Meanwhile, linolenic acid, resveratrol, Huperzia serrata, icariin, and baicalein protected against activated macrophages and microglia in experimental autoimmune encephalomyelitis and multiple sclerosis. Additionally, emodin, esters of gallic and rosmarinic acids, Agathisflavone, and sinomenine offered promising multiple sclerosis treatments. This review highlights the therapeutic potential of using nutraceuticals to treat neurodegenerative diseases involving microglial-related pathways.

Two new norcassane-type diterpenoids from Mezonevron sinense Hemsl

Two new norcassane-type diterpenoids, named 6β-hydroxy-bisnorcass-13-en-12-one (1) and 6β-hydroxy-bisnorcassan-12-one (2), were isolated from the seeds of Mezonevron sinense Hemsl. The structures of compounds 1-2 were determined by extensive spectroscopic analysis. Two compounds exhibited immunosuppressive activity with the IC₅₀ values of 19.35 ± 0.87 μM and 18.69 ± 0.88 μM in the ConA induced T cell model and 65.04 ± 0.83 μM and 48.06 ± 0.76 μM in LPS induced B cell model, respectively.

Diversified cassane family diterpenoids from the leaves of Caesalpinia minax exerting anti-neuroinflammatory activity through suppressing MAPK and NF-κB pathways in BV-2 microglia

ETHNOPHARMACOLOGICAL RELEVANCE

Caesalpinia minax Hance, whose seeds are known as "Ku-shi-lian" in China, have been used in Chinese folk medicine for treatment of rheumatism, dysentery, and skin itching. However, the anti-neuroinflammatory constituents of its leaves and their mechanism are rarely reported.

AIM OF THE STUDY

To search for new anti-neuro-inflammatory compounds from the leaves of C. minax and elucidate their mechanism on anti-neuroinflammatory effect.

MATERIALS AND METHODS

The main metabolites of the ethyl acetate fraction from C. minax were analyzed and purified via HPLC and various column chromatography techniques. Their structures were elucidated on the basis of 1D and 2D NMR, HR-ESI-MS, and single crystal X-ray diffraction analysis. Anti-neuroinflammatory activity was evaluated in BV-2 microglia cells induced by LPS. The expression levels of molecules in NF-κB and MAPK signaling pathways were analyzed through western blotting. Meanwhile, the time- and dose-dependent expression of associated proteins such as iNOS and COX-2 were detected by western blotting. Furthermore, Compounds 1 and 3 were performed on the NF-κB p65 active site using molecular docking simulation to elucidate the molecular level inhibition mechanism.

RESULTS

20 cassane diterpenoids, including two novel ones (caeminaxins A and B) were isolated from the leaves of C. minax Hance. Caeminaxins A and B possessed a rare unsaturated carbonyl moiety in their structures. Most of the metabolites exhibited potent inhibition effects with IC₅₀ values ranging from 10.86 ± 0.82 to 32.55 ± 0.47μM. Among them, caeminaxin A inhibited seriously the expression of iNOS and COX-2 proteins and restrained the phosphorylation of MAPK and the activation of NF-κB signaling pathways in BV-2 cells. The anti-neuro-inflammatory mechanism of caeminaxin A has been studied systematically for the first time. Furthermore, biosynthesis pathways for compounds 1-20 were discussed.

CONCLUSIONS

The new cassane diterpenoid, caeminaxin A, alleviated the expression of iNOS and COX-2 protein and down-regulated of intracellular MAPK and NF-κB signaling pathways. The results implied that cassane diterpenoids had potential to be developed into therapeutic agents for neurodegenerative disorders such as Alzheimer's disease.

Three new cassane-type diterpenoids from Caesalpinia sinensis

Three new cassane-type diterpenoids, namely, (4S)-6β,12α,19-trihydroxy-cass-13(15)-en-16,12-olide (1), cass-13(15)-en-​16,12-olide (2), and 12α-hydroxy-cass-13(15)-en-16,12-olide (3), were isolated from the seeds of Caesalpinia sinensis. The structures of 1-3 were established by extensive spectroscopic analysis, and their absolute configurations were assigned by electronic circular dichroism (ECD) calculations. The inhibitory activities against PTP1B of the isolated compounds were evaluated. The results showed that compound 2 possessed PTP1B inhibitory activity with an IC₅₀ value of 217.45 ± 36.4 μM.

Cassane diterpenoids from Caesalpinia pulcherrima and their anti-inflammatory and α-glycosidase inhibitory activities

Three undescribed cassane-type diterpenoids (CAs), caesalpulcherrins K-M (1-3), together with three known ones (4-6) were isolated from the aerial parts of Caesalpinia pulcherrima (L.) Sw (Fabaceae). Their structures were elucidated via analysis of NMR (1 D and 2 D) and HRESIMS data. The character for caesalpulcherrin K possessing the olefin bond at C-11 and C-12 in its cassane skeleton was observed, which belonged to a small group among more than 450 CAs. That is, only fifteen derivatives have been reported up to now, to our knowledge. Biological evaluation revealed that compounds 1-6 exhibited moderate anti-inflammatory activity, with an IC₅₀ value from 6.04 ± 0.34 to 8.92 ± 0.65 μM. Furthermore, compounds 5 and 6 exhibited significant α-glucosidase inhibitory activity at 10 μM.

Phanginin R Induces Cytoprotective Autophagy via JNK/c-Jun Signaling Pathway in Non-Small Cell Lung Cancer A549 Cells

BACKGROUND

Cassane-type diterpenoids are widely distributed in the medical plants of genus Caesalpinia. To date, plenty of cassane diterpenoids have been isolated from the genus Caesalpinia, and some of them were documented to exhibit multiple biological activities. However, the effects of these compounds on autophagy have never been reported.

OBJECTIVE

To investigate the effects and mechanisms of the cassane diterpenoids including Phanginin R (PR) on autophagy in Non-Small Cell Lung Cancer (NSCLC) A549 cells.

METHODS

Western blot analysis and immunofluorescence assay were performed to investigate the effects of the compounds on autophagic flux in A549 cells. The pathway inhibitor and siRNA interference were used to investigate the mechanism of PR. MTT assay was performed to detect cell viability.

RESULTS

PR treatment upregulated the expression of phosphatidylethanolamine-modified microtubule-associated protein Light-Chain 3 (LC3-II) in A549 cells. Immunofluorescence assay showed that PR treatment increased the production of red-fluorescent puncta in mRFP-GFP-LC3 plasmid-transfected cells, indicating PR promoted autophagic flux in A549 cells. PR treatment activated the c-Jun N-terminal Kinase (JNK) signaling pathway while it did not affect the classical Akt/mammalian Target of Rapamycin (mTOR) pathway. Pretreatment with the JNK inhibitor SP600125 or siRNA targeting JNK or c-Jun suppressed PR-induced autophagy. In addition, cotreatment with the autophagy inhibitor Chloroquine (CQ) or inhibition of the JNK/c-Jun signaling pathway increased PR-induced cytotoxicity.

CONCLUSION

PR induced cytoprotective autophagy in NSCLC A549 cells via the JNK/c-Jun signaling pathway, and autophagy inhibition could further improve the anti-cancer potential of PR.

Four new cassane-type diterpenoids from the seed kernels of Caesalpinia cucullata Roxb

The first investigation of chemical composition in seed kernels of Caesalpinia cucullata Roxb. resulted in the separation of four new cassane diterpenes, including three furanoditerpenes (1, 2 and 4) and one tricyclic type (3). It was the first found cassane diterpenoids from this plant. Their gross structures were elucidated by means of comprehensive spectroscopic analysis (UV, IR, NMR, HRESIMS) as well as electronic circular dichroism (ECD) calculation. The compound 1 possess a rare isomerized dihydrofuran ring in structure framework. In bioassay, compounds 1-4 exhibited moderate anti-inflammatory activity by inhibiting production of NO in LPS-induced RAW 264.7 cells.

Butyrolactone and sesquiterpene derivatives as inhibitors of iNOS from the roots of Lindera glauca

Nine previously undescribed butyrolactone and sesquiterpene derivatives, named cyclopentanone A (1), subamolides F and G (2 and 3), secosubamolide F (4), rupestonic acids J - L (5-7), linderaguaianols A and B (8 and 9), together with six known ones 10-15 were isolated from the roots of Lindera glauca. Their structures, including their absolute configurations were elucidated by extensive spectroscopic analysis, quantum chemical calculations, and Mo₂(AcO)₄-induced circular dichroism. Compound 1 that possessed a unique five-membered cyclopentane skeleton with a side chain was rarely found from natural sources. The biogenetic pathway for 1-4 was postulated. Secosubamolide F (4) inhibited nitric oxide (NO) production in lipopolysaccharide (LPS)-activated RAW264.7 cells with IC₅₀ value of 1.73 ± 0.18 μM and also significantly suppressed the production of iNOS. The binding interactions between 4 and iNOS were investigated using docking analyses.

Chemical composition, biological properties and bioinformatics analysis of two Caesalpina species: A new light in the road from nature to pharmacy shelf

Caesalpinia bonduc and C. decapeleta var. japonica have great importance in traditional medicine systems but scientific information's are still lacking for their potentials. To explore their bioactivity, we assessed the antioxidant, enzyme inhibitory abilities of the dichloromethane (DCM), ethyl acetate, methanol, and water extracts prepared from the leaves and bark. The cytotoxicity and anticancer properties of the extracts were also assessed in vitro. The water extract of C. decapeleta leaves possessed highest phenolic content (108.16 mg gallic acid equivalent (GAE)/g extract), while the highest flavonoid content was recorded for the C. bonduc leaf methanolic extract (27.89 mg rutin equivalent (RE)/g extract). In general, C. decapeleta extracts possessed higher radical scavenging potential compared to C. bonduc extracts. C. decapeleta DCM leaves extract (10.20 mg galantamine equivalent (GALAE)/g extract) showed highest inhibition against butyrylcholinesterase. The cytotoxicity of the most potent methanolic and aqueous extracts were assessed against four cell lines. The chemical profiles of both species appeared to be different. C. bonduc was abundant in organic and phenolic acids as well as their esters. Flavonoid glycosides, bonducellin and its derivatives and caesalminaxins were identified. Whereas, C. decalpetala possessed many galloylated compounds. The cytotoxicity of C. bonduc and C. decapetala extracts was tested using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) based assay on VERO (kidney of an adult African Green monkey cells), HeLa (human cervical adenocarcinoma cells), RKO (human colon carcinoma cells), FaDu (human hypopharyngeal squamous carcinoma cells) cell lines. C. bonduc bark water extract exhibited the highest cytotoxicity towards HeLa (50 % cytotoxic concentration (CC₅₀): 28.5 μg/mL) cancer cell line, as compared to normal VERO cells (CC₅₀:35.87 μg/mL). For C. decapetala, the highest cytotoxicity was found for bark methanol extract on the HeLa cells with CC₅₀ of 46.08 μg/mL and selectivity index of 3.33. In the gene ontology analysis, prostate cancer, nuclear factor kappa B (NF-kappa B) signaling, proteoglycans in cancer pathways might support the results of the cytotoxic assays. These results showed that the tested Caesalpinia species, showing potent inhibitory action against butyrylcholinesterase, might represent novel phytotherapeutic avenues for the management of Alzheimer's disease.

Pterolobirins A and B, Oxygen-Bridged Cassane Diterpenoid Dimers from the Fruits of Pterolobium macropterum

Two dimeric cassane diterpenoids with an unprecedented 6/6/6/6/6/5/6/6/6 nonacyclic framework, pterolobirins A and B (1 and 2), were isolated from the fruits of Pterolobium macropterum. Their structures were assigned by interpreting the spectroscopic data. The absolute configuration of 1 was unequivocally confirmed by single-crystal X-ray diffraction data. A putative biosynthetic pathway is proposed based on a regular intermolecular Diels-Alder reaction and an intramolecular nucleophilic addition.

Pseudoguaianelactones A–C: three unusual sesquiterpenoids from Lindera glauca with anti-inflammatory activities by inhibiting the LPS-induced expression of iNOS and COX-2

The pseudoguaianelactones A–C, three unusual sesquiterpenoids isolated from Lindera glauca, showed potential anti-inflammatory activities and also provide a new approach for anti-inflammatory drug discovery.