Synthesis and cytotoxic activity of some 3-benzyl-5-arylidenefuran-2(5H)-ones

Leishmanicidal and cytotoxic activities and 4D-QSAR of 2-arylidene indan-1,3-diones

The indan-1,3-dione and its derivatives are important building blocks in organic synthesis and present important biological activities. Herein, the leishmanicidal and cytotoxicity evaluation of 16 2-arylidene indan-1,3-diones is described. The compounds were evaluated against the leukemia cell lines HL60 and Nalm6, and the most effective ones were 2-(4-nitrobenzylidene)-1H-indene-1,3(2H)-dione (4) and 4-[(1,3-dioxo-1H-inden-2(3H)-ylidene)methyl]benzonitrile (10), presenting IC₅₀ values of around 30 µmol/L against Nalm6. The leishmanicidal activity was assessed on Leishmania amazonensis, with derivative 4 (IC₅₀ = 16.6 µmol/L) being the most active. A four-dimensional quantitative structure-activity analysis (4D-QSAR) was applied to the indandione derivatives, through partial least-squares regression. The statistics presented by the regression models built with the selected field descriptors of Coulomb (C) and Lennard-Jones (L) nature, considering the activities against L. amazonensis, HL60, and Nalm6 leukemia cells, were, respectively, R² = 0.88, 0.92, and 0.98; Q² = 0.83, 0.88, and 0.97. The presence of positive Coulomb descriptors near the carbonyl groups indicates that these polar groups are related to the activities. Besides, the presence of positive Lennard-Jones descriptors close to substituents R³ or R¹ indicates that bulky nonpolar substituents in these positions tend to increase the activities. This study provides useful insights into the mode of action of indandione derivatives for each biological activity involved.

Antioxidant and Antiproliferative Activity of Selected Medicinal Plants of Lower Assam, India: An In Vitro and In Silico Study

BACKGROUND

The use of medicinal plants for general wellbeing and disease treatment is a common practice among tribal communities of Kokrajhar districts of Assam. However, little works have been done to study the pharmacological aspect of the plants.

OBJECTIVES

The present study intends to study the antioxidant and antiproliferative properties of selected medicinal plants used by the tribal communities of the Kokrajhar district of Assam since ancient times.

METHODS

Five traditionally important medicinal plants, namely, Cassia fistula, Citrus grandis, Lindernia crustacea, Sacciolepis myosuroides, and Zingiber zerumbet were investigated for antioxidant, antiproliferative (cytotoxic) and apoptosis-inducing potential in the malignant cancer cell line. Phytochemical content, such as phenolic and flavonoid content, were estimated following standard protocol. The methanolic extract of plants was investigated following the phosphomolybdate method (TAC), FRAP, DPPH, ABTS, and TBARS assays. Antiproliferative activities of the plants were carried out by MTT assay in DL and PBMC cells. The apoptotic study was carried out following the acridine orange and ethidium bromide staining method and fluorescent microscopic imaging. Based on the significant (P≤0.05) high apoptotic inducing potential of the plant and to further dissect the molecular mode of action, including downstream biological action, major phytochemicals derived from L. crustacea were investigated for its prospective binding affinity with anti-apoptotic cancer target proteins.

RESULTS

Antioxidant studies by FRAP, DPPH, ABTS, and TBARS assay revealed that all five plants contain considerable free radical scavenging activity. C. fistula showed the strongest free radical scavenging activity while the fruit peel extract of C. grandis showed poor activity. The overall antioxidant activities of plants such as TAC, FRAP, DPPH, ABTS, and TBARS may be arranged in decreasing activity as C. fistula > Z. zerumbet > L. crustacea > S. myosuroides > C. grandis. MTT based cell proliferation study showed that all the plants extract significantly (P≤0.05) inhibited cell viability with negligible cytotoxicity (~5-12%) in normal cells. Moreover, L. crustacea showed promising antiproliferative and apoptosis-inducing ability against Dalton's lymphoma. It is worth mentioning that the major bioactive compounds of the most potent plant extract, L. crustacea interacted with anti-apoptotic proteins (cancer target) with higher affinity and the results are compared with reference inhibitors.

CONCLUSION

It is worth noting that these plants have the potential to consider for further scientific studies in different cell lines and animal models. Furthermore, isolation and characterization of bioactive compound(s) may promise the discovery of new and valuable drugs candidate to tackle various human diseases.

(Z)-5-(3′,4′-Bis(benzyloxy)benzylidene)furan-2(5H)-one

Over the years secondary metabolites have been considered as lead molecules both in their natural form and as templates for medicinal chemistry. Some secondary metabolites such as polyphenols and flavan-3-ols exert beneficial effects after a modification by the microbiota. Synthetic precursors of some of these modified compounds, in turn, carried a γ-alkylidenebutenolide moiety which characterizes a large class of bioactive natural products endowed with a wide range of biological activities. For these reasons stereoselective preparation of γ-alkylidenebutenolide continues to be an important issue for organic chemists. Our objective is to synthetize the novel compound (Z)-5-(3′,4′-bis(benzyloxy)benzylidene)furan-2(5H)-one in a stereocontrolled-one-pot reaction. The product was obtained in good yield. Furthermore, the theoretical investigation of the transition states suggests a new procedure to achieve Z-isomer of β-unsubstituted γ-alkylidenebutenolide.

Biologically relevant and energetically significant cooperative ternary (π–π)2/(π–π)1/(π–π)2 assemblies and fascinating discrete (H2O)21 clusters in isostructural 2,5-pyridine dicarboxylato Co(ii) and Zn(ii) phenanthroline compounds: antiproliferative evaluation and theoretical studies

Cytotoxicity in cancer cells with structure activity relationship has been explored in isostructural Co(ii) and Zn(ii) compounds involving energetically significant cooperative (π–π)₂/(π–π)₁/(π–π)₂ assemblies and fascinating (H₂O)₂₁ clusters.

Goodyschle A, a new butenolide with significant BchE inhibitory activity from Goodyera schlechtendaliana

Goodyschle A (1), a new butenolide, was isolated from the whole grass of Goodyera schlechtendaliana, an orchidaceous edible medicinal plant. The structure of the new compound was elucidated by 1 D and 2 D NMR experiments in addition to HRESIMS analyses. Compound 1 was evaluated for its bioactivities including cytotoxic activity against human gastric cancer (SGC-7901) and human hepatocellular carcinoma (HepG2) cell lines, inhibitory activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), and DPPH radical scavenging activity. As a result, compound 1 showed potent BChE inhibitory activity (IC₅₀ value = 6.88 ± 1.63 μM), moderate DPPH radical scavenging activity (IC₅₀ value = 16.25 ± 0.21 μM), and slight AChE inhibitory and cytotoxic activities. These findings suggest that compound 1 is worthy for further investigations in terms of its selective BChE inhibitory activity.

Oxalato bridged coordination polymer of manganese(iii) involving unconventional O⋯π-hole(nitrile) and antiparallel nitrile⋯nitrile contacts: antiproliferative evaluation and theoretical studies

Unconventional O⋯π-hole(nitrile) and antiparallel nitrile⋯nitrile contacts have been theoretically investigated for a Mn(iii) coordination polymer considering cytotoxicity, apoptosis, ROS generation, molecular docking and pharmacophore features.

Unconventional DNA-relevant π-stacked hydrogen bonded arrays involving supramolecular guest benzoate dimers and cooperative anion–π/π–π/π–anion contacts in coordination compounds of Co(ii) and Zn(ii) phenanthroline: experimental and theoretical studies

Antiproliferative evaluation and supramolecular assemblies of Co(ii) and Zn(ii) coordination compounds involving cooperative anion–π and unconventional DNA-relevant π-stacked hydrogen bonded arrays.

Adipato bridged novel hexanuclear Cu(ii) and polymeric Co(ii) coordination compounds involving cooperative supramolecular assemblies and encapsulated guest water clusters in a square grid host: antiproliferative evaluation and theoretical studies

Novel adipato bridged Cu(ii) and Co(ii) complexes synthesized by considering cytotoxicity, apoptosis, ROS generation, molecular docking and pharmacophore features.

Charge-assisted hydrogen bond and nitrile⋯nitrile interaction directed supramolecular associations in Cu(ii) and Mn(ii) coordination complexes: anticancer, hematotoxicity and theoretical studies

Charge-assisted H-bonds and nitrile⋯nitrile interactions directed assemblies in Cu(ii) and Mn(ii) complexes have been analyzed by MEP surface and NCI plot index. Anticancer activities and hematotoxictiy have been investigated.

Rubrolide analogues and their derived lactams as potential anticancer agents

Analogues of rubrolides were synthesized and shown to be cytotoxic to several cancer cell lines and not toxic to L929 normal cells. The cytotoxicity involved the induction of cell death by apoptosis.

The fungal phytotoxin alternariol 9-methyl ether and some of its synthetic analogues inhibit the photosynthetic electron transport chain

Alternariol and monomethylalternariol are natural phytotoxins produced by some fungal strains, such as Nimbya and Alternaria. These substances confer virulence to phytopathogens, yet no information is available concerning their mode of action. Here we show that in the micromolar range alternariol 9-methyl ether is able to inhibit the electron transport chain (IC50 = 29.1 ± 6.5 μM) in isolated spinach chloroplasts. Since its effectiveness is limited by poor solubility in water, several alternariol analogues were synthesized using different aromatic aldehydes. The synthesized 6H-benzo[c]cromen-6-ones, 5H-chromene[4,3-b]pyridin-5-one, and 5H-chromene[4,3-c]pyridin-5-one also showed inhibitory properties, and three 6H-benzo[c]cromen-6-ones were more effective (IC50 = 12.8-22.8 μM) than the lead compound. Their addition to the culture medium of a cyanobacterial model strain was found to inhibit algal growth, with a relative effectiveness that was consistent with their activity in vitro. In contrast, the growth of a nonphotosynthetic plant cell culture was poorly affected. These compounds may represent a novel lead for the development of new active principles targeting photosynthesis.

Synthesis and antiproliferative activity of C-3 functionalized isobenzofuran-1(3H)-ones

A series of thirteen C-3 functionalized isobenzofuran-1(3H)-ones (phtalides) was synthesized via condensation, aromatization, and acetylation reactions. NMR (one and two dimensional experiments), IR, and mass spectrometry analysis allowed confirmation of the identity of the synthesized compounds. The substances were submitted to in vitro bioassays against U937 (lymphoma) and K562 (myeloid leukemia) cancer cell lines using the MTT cytotoxicity assay. Some derivatives inhibited 90% of cell viability at 100 µM. Also, two phtalides presented biological activity superior than that of etoposide (VP16), a commercial drug used as a positive control in the assays. In silico drug properties of the evaluated compounds were calculated and the results are discussed.

Synthesis of rubrolide analogues as new inhibitors of the photosynthetic electron transport chain

Many natural products have been used as a model for the development of new drugs and agrochemicals. Following this strategy 11 rubrolide analogues, bearing electron-withdrawing and -donating groups at both benzene rings, were prepared starting from commercially available mucobromic acid. The ability of all compounds to inhibit the photosynthetic electron transport chain in the chloroplast was investigated. The rubrolide analogues were effective in interfering with the light-driven ferricyanide reduction by isolated chloroplasts. The IC(50) values of the most active derivatives are in fact only 1 order of magnitude higher than those of commercial herbicides sharing the same mode of action, such as Diuron (0.27 μM). QSAR studies indicate that the most efficient compounds are those having higher ability to accept electrons, either by a reduction process or by an electrophilic reaction mechanism. The results obtained suggest that the rubrolide analogues represent promising candidates for the development of new active principles targeting photosynthesis to be used as herbicides.

Synthesis of photosynthesis-inhibiting nostoclide analogues

A series of 34 3-benzyl-5-(arylmethylene)furan-2(5H)-ones, designed using the naturally occurring toxins nostoclides as a lead structure, was synthesized as potential inhibitors of the photosynthetic electron transport. All compounds were fully characterized by IR, NMR (1H and 13C), and MS spectrometry. HMBC and HSQC bidimensional experiments allowed 13C and 1H assignments. Their biological activities were evaluated in vitro as the ability to interfere with light-driven reduction of ferricyanide by isolated spinach chloroplasts. About two-thirds of the compounds exhibited inhibitory properties in the micromolar range against the basal electron flow from water to K3[Fe(CN)6]. The inhibitory potential of these 3-benzyl-5-(arylmethylene)furan-2(5H)-one lactones is higher than that of other nostoclide analogues previously synthesized in the same laboratories.