Rational design, synthesis, and pharmacological properties of pyranochalcone derivatives as potent anti-inflammatory agents

Potent insecticidal activity of Eleocharis dulcis (Burm. f.) Trin peel extract and its main components against aphids

BACKGROUND

Aphids are significant pests of cash crops and food farm crops. Botanical insecticides are safe for aphid control, especially for organic farming. In this study, Eleocharis dulcis (Burm. f.) Trin. peel extract (EDPE), a new botanical insecticide, was investigated for its active compositions against several agricultural aphids.

RESULTS

The results showed that the EDPE had high insecticidal activity against Sitobion avenae Fabricius, Aphis gossypii Glover, Megoura crassicauda Mordvilko, and Acyrthosiphon pisum Harris, with half-lethal concentration (LC₅₀ ) values of 95.92, 81.04, 140.31, and 255.73 mg/L after 48 h of treatment. In the pot culture assay, the aphicidal effects of 25% EDPE soluble liquid (SL) at a concentration of 0.016% were 68.98 ± 5.61%, 79.33 ± 8.27%, and 88.82 ± 3.91% after the first, third, and seventh days of treatment, respectively. Nine compounds were identified by bioactivity-directed fractionation: 4',5'-dimethoxy-6,6-dimethylpyranoisoflavone (1), 3-methoxy-4-hydroxylonchocarpin (2), 4-hydroxylonchocarpin (3), 4-methoxylonchocarpin (4), barbigerone (5), lonchocarpusone (6), 6a,12a-dehydrodeguelin (7), 13-homo-13-oxa-6a, 12a-dehydrodeguelin (8) and deguelin (9). Among them, 4-hydroxylonchocarpin (3) showed the highest aphidicidal activity against M. crassicauda, S. avenae, and A. pisum, with LC₅₀ values of 97.24, 140.63, and 112.31 mg/L, respectively.

CONCLUSION

These data contribute to a better understanding of the aphicidal activity of EDPE and its main component, 4-hydroxylonchocarpin. This will help to develop new botanical insecticides to contro aphids. © 2022 Society of Chemical Industry.

Growth Inhibition of Two Prenylated Chalcones on Prostate Cancer Cells through the Regulation of the Biological Activity and Protein Translation of Bloom Helicase

Bloom (BLM) helicase is an important member of the RecQ family of DNA helicases that plays a vital role in the maintenance of genomic stability. The defect of BLM helicase leads to a human genetic disorder called Bloom syndrome, characterized by genomic instability, specific phenotypic features, and a predisposition to many types of cancer. The predisposition to cancer caused by BLM helicase is due to defects in important DNA metabolic pathways such as replication, recombination, and repair. Therefore, the aim of this work was to investigate the effects of two prenylated chalcones, WZH-10 and WZH-43, on the expression of BLM helicase in prostate cancer cells, as well as the biological activity of the purified BLM helicase from cancer cells. This might lead to a better understanding of the role of BLM helicase in the aforementioned DNA metabolic pathways that directly influence chromosomal integrity leading to cancer. The results indicated that the two prenylated chalcones inhibited the growth of prostate cancer cells PC3 by inducing apoptosis and arresting the cell cycle. However, they only inhibited the protein expression of BLM helicase without regulating its transcriptional expression. In addition, they did not significantly regulate the expression of the homologous family members WRN and RECQL1, although the DNA unwinding and ATPase activity of BLM helicase were inhibited by the two prenylated chalcones. Finally, a negligible effect was found on the DNA-binding activity of this enzyme. These results demonstrated that prenylated chalcones can be an effective intervention on the expression and function of the BLM helicase protein in cancer cells to inhibit their growth. Therefore, they might provide a novel strategy for developing new anti-cancer drugs targeting the genomic stability and DNA helicase.

Synthesis of pyranochalcone derivatives and their inhibitory effect on NF-κB activation

In an effort to identify novel inhibitors of nuclear factor kappa B (NF-κB), twenty five pyranochalcone derivatives were synthesized and evaluated for their in vitro activities against TNF-α induced NF-κB inhibition in HEK293T cells. Among all of these derivatives, several displaying the same acrylate moiety on the B ring exhibited potent inhibition, with IC₅₀ values ranging from 0.29 to 10.46 μM. A functional study of the most potent of these compounds, designated 6b, revealed that it significantly suppressed the transcriptional expression of inflammatory factor IL-1β in lipopolysaccharide-induced RAW 264.7 macrophages, and also mildly inhibited CCL2, IL6 and TNF-α. In addition, compound 6b was found to inhibit IL-1β released in LPS-induced BMDM cells. This study demonstrates that the inhibitory effect of 6b on LPS-stimulated inflammatory mediator production in the mouse macrophage cell line RAW 264.7 correlates with the suppression of the NF-κB and MAPK signaling pathways.

Fli-1 Activation through Targeted Promoter Activity Regulation Using a Novel 3', 5'-diprenylated Chalcone Inhibits Growth and Metastasis of Prostate Cancer Cells

The friend leukemia integration 1 (Fli-1) gene is involved in the expression control of key genes in multiple pathogenic/physiological processes, including cell growth, differentiation, and apoptosis; this implies that Fli-1 is a strong candidate for drug development. In our previous study, a 3′,5′-diprenylated chalcone, (E)-1-(2-hydroxy-4-methoxy-3,5-diprenyl) phenyl-3-(3-pyridinyl)-propene-1-one (C10), was identified as a novel anti-prostate cancer (PCa) agent. Here, we investigated the molecular mechanisms underlying the anti-cancer effects of C10 on the growth, metastasis, and invasion of PC3 cells in vitro. Our results show that C10 exhibited a strong inhibitory effect on proliferation and metastasis of PC3 cells via several cellular and flow cytometric analyses. Further mechanism studies revealed that C10 likely serves as an Fli-1 agonist for regulating the expression of Fli-1 target genes including phosphatidylinositol 3-kinase (P110), murine double minute2 (MDM2), B-cell lymphoma-2 (Bcl-2), Src homology-2 domain-containing inositol 5-phosphatase 1 (SHIP-1), and globin transcription factor-1 (Gata-1) as well as the phosphorylation of extracellular-regulated protein kinases 1 (ERK1). Further, we confirmed that C10 can regulate the expressions of vascular endothelial growth factor 1 (VEGF-1), transforming growth factor-β2 (TGF-β2), intercellular cell adhesion molecule-1 (ICAM-1), p53, and matrix metalloproteinase 1 (MMP-1) genes associated with tumor apoptosis, migration, and invasion. Thus, C10 exhibits stronger anticancer activity with novel molecular targets and regulatory molecular mechanisms, indicating its great potency for development as a novel targeted anticancer drug.

Development of a novel nitric oxide (NO) production inhibitor with potential therapeutic effect on chronic inflammation

Inflammation is a complex biological response to stimuli. Activated macrophages induced excessively release of pro-inflammatory cytokines and mediators such as endogenous radical nitric oxide (NO) play a significant role in the progression of multiple inflammatory diseases. Both natural and synthetic chalcones possess a wide range of bioactivities. In this work, thirty-nine chalcones and three related compounds, including several novel ones, based on bioactive kava chalcones were designed, synthesized and their inhibitory effects on NO production in RAW 264.7 cells were evaluated. The novel compound (E)-1-(2'-hydroxy-4',6'-dimethoxyphenyl)-3-(3-methoxy-4-(3-morpholinopropoxy)phenyl)prop-2-en-1-one (53) exhibited a better inhibitory activity (84.0%) on NO production at 10 μM (IC₅₀ = 6.4 μM) with the lowest cytotoxicity (IC₅₀ > 80 μM) among the tested compounds. Besides, western blot analysis indicated that compound 53 was a potent down-regulator of inducible nitric oxide synthase (iNOS) protein. Docking study revealed that compound 53 also can dock into the active site of iNOS. Furthermore, at the dose of 10 mg/kg/day, compound 53 could both significantly suppress the progression of inflammation on collagen-induced arthritis (CIA) and adjuvant-induced arthritis (AIA) models. In addition, the structure-activity relationship (SAR) of the kava chalcones based analogs was also depicted.

Inducible nitric oxide synthase inhibitors: A comprehensive update

Inducible nitric oxide synthase (iNOS), which is expressed in response to bacterial/proinflammatory stimuli, generates nitric oxide (NO) that provides cytoprotection. Overexpression of iNOS increases the levels of NO, and this increased NO level is implicated in pathophysiology of complex multifactorial diseases like Parkinson's disease, Alzheimer's disease, multiple sclerosis, rheumatoid arthritis, and inflammatory bowel disease. Selective inhibition of iNOS is an effective approach in treatment of such complex diseases. l-Arginine, being a substrate for iNOS, is the natural lead to develop iNOS inhibitors. More than 200 research reports on development of nitric oxide synthase inhibitors by different research groups across the globe have appeared in literature so far. The first review on iNOS, in 2002, discussed the iNOS inhibitors under two classes that is, amino acid and non-amino acid derivatives. Other review articles discussing specific chemical classes of iNOS inhibitors also appeared during last decade. In the present review, all reports on both natural and synthetic iNOS inhibitors, published 2002 onwards, are studied, classified, and discussed to provide comprehensive information on iNOS inhibitors. The synthetic inhibitors are broadly classified into two categories that is, arginine and non-arginine analogs. The latter are further classified into amidines, five- or six-membered heterocyclics, fused cyclics, steroidal type, and chalcones analogs. Structures of the most/significantly potent compounds from each report are provided to know the functional groups important for incurring iNOS inhibitory activity and selectivity. This review is aimed to provide a comprehensive view to the medicinal chemists for rational designing of novel and potent iNOS inhibitors.

From Carbamate to Chalcone: Consecutive Anionic Fries Rearrangement, Anionic Si → C Alkyl Rearrangement, and Claisen-Schmidt Condensation

A highly efficient one-pot procedure was developed for the synthesis of various 2'-hydroxychalcones from phenyl diethylcarbamate, featuring consecutive Snieckus-Fries rearrangement, anionic Si → C alkyl rearrangement, and Claisen-Schmidt condensation in a single operation. The applicability of this protocol was demonstrated by the highly efficient synthesis of the anti-inflammatory natural product lonchocarpin. The mechanism insight is also provided.

Synthesis and Antiproliferative Activity of Minor Hops Prenylflavonoids and New Insights on Prenyl Group Cyclization

Synthesis of minor prenylflavonoids found in hops and their non-natural derivatives were performed. The antiproliferative activity of the obtained compounds against some human cancer cell lines was investigated. Using xanthohumol isolated from spent hops as a lead compound, a series of minor hop prenylflavonoids and synthetic derivatives were obtained by isomerization, cyclisation, oxidative-cyclisation, oxidation, reduction and demethylation reactions. Three human cancer cell lines-breast (MCF-7), prostate (PC-3) and colon (HT-29)-were used in antiproliferative assays, with cisplatin as a control compound. Five minor hop prenyl flavonoids and nine non-natural derivatives of xanthohumol have been synthetized. Syntheses of xanthohumol K, its dihydro- and tetrahydro-derivatives and 1″,2″,α,β-tetrahydroxanthohumol C were described for the first time. All of the minor hops prenyl flavonoids exhibited strong to moderate antiproliferative activity in vitro. The minor hops flavonoids xanthohumol C and 1″,2″-dihydroxanthohumol K and non-natural 2,3-dehydroisoxanthohumol exhibited the activity comparable to cisplatin. Results described in the article suggest that flavonoids containing chromane- and chromene-like moieties, especially chalcones, are potent antiproliferative agents. The developed new efficient, regioselective cyclisation reaction of the xanthohumol prenyl group to 1″,2″-dihydroxantohumol K may be used in the synthesis of other compounds with the chromane moiety.

Anti-Inflammatory Pyranochalcone Derivative Attenuates LPS-Induced Acute Kidney Injury via Inhibiting TLR4/NF-κB Pathway

Treatment of septic acute kidney injury (AKI) has still been beyond satisfaction, although anti-inflammatory therapy is beneficial for sepsis-induced AKI. Compound 5b was derived from natural pyranochalcones and exhibited potent anti-inflammatory activity in adjuvant-induced arthritis. In this study, we aimed to investigate the renoprotective effects and potential mechanism of 5b against lipopolysaccharide (LPS)-induced AKI. C57BL/6 mice and human renal proximal tubule cell line (HK-2 cell) were treated with LPS, respectively. Compound 5b was orally administrated at a dose of 25 mg/kg/day for 5 days before LPS (10 mg/kg) intraperitoneal injection. Cells were pretreated with 25 μg/mL 5b for 30 min before LPS (1 μg/mL) treatment. Pretreatment with 5b markedly alleviated tubular injury and renal dysfunction in LPS-induced AKI. The expression of IL-1β, IL-6, and TNF-α both in renal tissue of AKI mice and in the LPS-stimulated HK-2 cell culture medium were reduced by 5b treatment (p < 0.05). The results of immunohistochemistry staining showed that 5b reduced the expression of NF-κB p65 in kidneys. Similarly, 5b decreased the LPS-induced levels of NF-κB p65 and TLR4 proteins in kidneys and HK-2 cells. These data demonstrated that a potent pyranochalcone derivative, 5b, exhibited renoprotective effect against LPS-induced AKI, which was associated with anti-inflammatory activity by inhibiting the TLR4/NF-κB pathway.

Inhibition of pro-inflammatory mediators in RAW264.7 cells by 7-hydroxyflavone and 7,8-dihydroxyflavone

OBJECTIVES

Flavonoids are a class of compounds that having the benzo-γ-pyrone skeleton, which possess anti-inflammatory properties in vitro and in vivo. The aim of this study was to investigate the inhibition of two flavonoids 7-hydroxyflavone (HF) and 7,8-dihydroxyflavone (DHF) on the production of pro-inflammatory mediators in RAW264.7 cells activated by lipopolysaccharides (LPS).

METHODS

For this purpose, we selected four pro-inflammatory mediators including nitric oxide (NO), prostaglandin E₂ (PGE₂ ), tumour necrosis factor-α (TNF-α) and interleukin-6 (IL-6) as markers to evaluate the anti-inflammatory activity of HF and DHF.

KEY FINDINGS

In this regard, we showed that HF and DHF dose-dependently reduced the production of NO, PGE₂ , TNF-α and IL-6 through downregulating mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX2), TNF-α and IL-6, respectively. Moreover, DHF generally possesses more efficient than HF in reducing these markers secretion in this study.

CONCLUSIONS

Consider together, these findings suggest that DHF and HF can inhibit LPS-induced inflammation via attenuating the production of NO, PGE₂ , TNF-α and IL-6, indicating that they may be lead compounds for developing anti-inflammatory agent.

Hesperetin derivatives: Synthesis and anti-inflammatory activity

Sixteen novel hesperetin derivatives containing Mannich base moiety were designed and synthesized and their anti-inflammatory activities were evaluated by inhibiting tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in mouse RAW264.7 macrophages. Compounds 3a-3k showed better hydrophilic, while compounds 3l-3p with aromatic groups was hydrophobic. The anti-inflammatory activity of title compounds was correlated with logP values, among them, compounds 3c, 3e and 3i with minus logP values exhibited best anti-inflammatory activity through decreasing both IL-6 and TNF-α. Furthermore, the expression of LPS-induced notch1 and inos was reduced by compounds 3c, 3e, and 3i, and compound 3e attenuated LPS-induced inos protein levels in a dose-dependent manner.

(E)-3-(3,4-Dimethoxyphenyl)-1-(5-hydroxy-2,2-dimethyl-2H-chromen-6-yl)prop-2-en-1-one ameliorates the collagen-arthritis via blocking ERK/JNK and NF-κB signaling pathway

Our previous report has shown a natural pyranochalcones-derived compound, (E)-3-(3,4-Dimethoxyphenyl)-1-(5-hydroxy-2,2-dimethyl-2H-chromen-6-yl)prop-2-en-1-one (5b), that exerted protection against carrageenan-induced hind paw edema and adjuvant-induced arthritis. In this study, collagen-induced arthritis (CIA) model was used to further examine the anti-arthritic effects of 5b in vivo; the underlying molecular mechanisms of action were also investigated using a murine monocytic cell line, RAW264.7 cells. Here we showed that oral administration of 5b (20mg/kg) significantly suppressed the progression of arthritis. Improvement in disease severity was accompanied by inhibition of CD68-positive cells in knee joint and reduced pro-inflammatory cytokines TNF-α, IL-1β and IL-6 in serum. In vitro, 5b suppressed expressions of iNOS, cyclooxygenase-2 (COX-2), TNF-α, IL-6 and IL-1β as well as productions of nitric oxide (NO) and prostaglandin E2 (PGE2) in lipopolysaccharide (LPS)-treated macrophages. This compound also significantly suppressed LPS-induced NF-κB activation, including phosphorylation of I-κB, degradation of I-κB, and nuclear translocation of p65 and p50. Treatment with 5b also blocked LPS-induced expression of TLR4 remarkably, suppressed degradation of IRAKs and phosphorylations of JNK and ERK, but had little effect to p38 kinase activation. These findings indicated that 5b might be a therapeutic agent for rheumatoid arthritis, and exerted an anti-inflammatory effect mainly through mediating TLR4, NF-κB and ERK/JNK signaling pathways in monocytes.