Immunomodulatory properties of S- and N-alkylated 5-(1H-indol-2-yl)-1,3,4-oxadiazole-2(3H)-thione

N-(2-hydroxy phenyl) acetamide ameliorate inflammation and doxorubicin-induced nephrotoxicity in rats

Doxorubicin (DOX) is an anthracyclin antibiotic used for the treatment of various cancers. Nephrotoxicity is among the serious side effects of DOX, therefore, DOX-induced nephrotoxic model has been widely used to study nephropathies. The objectives of this study is to investigate the possible anti-inflammatory and nephroprotective effects of salicylic acid derivative, N-(2-hydroxy phenyl) acetamide (NA-2), in a rat model of DOX-induced nephrotoxicity. The in vitro anti-inflammatory potential of NA-2 was manifested by whole blood oxidative burst and nitric oxide (NO) assays with no toxicity on normal human fibroblast (BJ) cells, human embryonic kidney (HEK-293) cells, and normal monkey kidney epithelial (Vero) cells. The in vivo study included five groups: Normal control, DOX (6 mg/kg DOX-i.v.via tail vein), NA-2 treated control-i.p., NA-2/DOX treated-i.p., and prednisolone/DOX treated. After 7 days of DOX administration, rats with urinary protein level of >50 mg/kg/day were selected. Treatment group rats received i.p. doses of NA-2 (10 mg/kg/day) for 3 weeks with weekly monitoring of urinary protein excretion and body weights. mRNA expression of interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, monocyte chemoattractant protein (MCP)-1, and kidney injury molecule (KIM)-1 was analyzed by quantitative polymerase chain reaction (qPCR). Protein expressions were analyzed by immunohistochemistry. NA-2 attenuated DOX-induced changes in serum and urine levels, and improved inflammatory profile of the renal tissue. Histopathological findings revealed protective effects of NA-2 showing lesser lesions. We conclude that NA-2 is able to protect against DOX-induced renal damage functionally, biochemically and histopathologically with corresponding improvement in the kidney inflammatory profile.

In-vitro inhibition of NLRP3 inflammasome by 3,6-dihydroxyflavone (3,6-DHF): a therapeutic strategy for the treatment of chronic inflammatory and autoimmune diseases

Nucleotide-binding oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) inflammasome complex has an important role in immune system and its abnormal activation is associated with the pathogenesis of various inflammatory and auto-immune diseases. The study reveals the anti-inflammatory effects of 3,6-dihydroxyflavone (3,6-DHF). Here, we aimed to determine the inhibitory effects of 3,6-DHF on NLRP3 inflammasome and its associated components, thereby determining the signaling pathways involved in the inhibition. Reactive oxygen species (ROS) and nitric oxide (NO) were quantified by chemiluminescence and Griess methods, respectively. Inflammatory cell model was induced in human leukemic monocytes (THP-1). mRNA levels were estimated through real-time RT-PCR, protein expressions were evaluated by protein slot blot and immunocytochemistry, MTT and alamar blue assays were employed for toxicity studies. The compound 3,6-DHF was found to be the potent inhibitor of NLRP3 inflammasome by targeting the molecules involve in its activation pathway. Anti-inflammatory effects were revealed by inhibition of ROS and NO, reduction in the transcription of caspase-1, ASC, IL-1β and TLR-4 was observed along with the marked inhibition of NLRP3, IL-18, NF-κB and pNF-κB at translational level. 3,6-DHF was non-toxic on normal human fibroblast (BJ) and THP-1 cells and, could be a potential therapeutic agent in NLRP3 inflammasome driven diseases.

Isoflavanquinones from Abrus precatorius roots with their antiproliferative and anti-inflammatory effects

Phytochemical studies on the root of Abrus precatorius Linn. (Fabaceae), leads towards the identification of four undescribed (abruquinones M, N, O, and P), and seven known abruquinones, (abruquinones A, E, B, F, I, D, and G). Spectroscopic analyses (1D, and 2D NMR, HRESI-MS) were used in elucidating structures of the all compounds. Evaluation of anticancer activities of the isolated isoflavanquinones revealed that abruquinones M, and N showed cytotoxicity against oral CAL-27 (IC₅₀ values 6.48 and 5.26 μM, respectively), and colon (Caco-₂) cell lines (IC₅₀ values 15.79 and 10.33 μM, respectively). Abruquinone M also inhibited the growth of lung cancer cells (NCI-H460) with IC₅₀ of 31.33 μM. The isolated isoflavanquiones also showed potent anti-inflammatory potential through phagocyte oxidative burst and pro-inflammatory cytokine TNF-α inhibition in vitro. These findings suggest isoflavanquinones from A. precatorius roots as candidates for further research in cancer treatment.

Diversified Thiazole Substituted Coumarins and Chromones as Non- Cytotoxic ROS and NO Inhibitors

Background:

Non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen, aspirin, indomethacin, flufenamic acid and phenylbutazone are used to treat most of the inflammatory disorders. These NSAIDs are also associated with serious side effects including gastric ulceration, nephrotoxicity, and bleeding, mainly due to acidic nature. Hence, there is a need to identify highly potent and safer treatment for inflammatory disorders.

Methods:

Herein, synthetic hydrazinyl thiazole substituted coumarins and chromones 1-48 were evaluated for ROS inhibitory activity. ROS were generated from zymosan activated whole blood phagocytes.

Results:

Among all tested compounds, compounds 1 (IC50 = 38.3 ± 7.1 μM), 2 (IC50 = 5.7 ± 0.2 μM), 5 (IC50 = 28.3 ± 3.5 μM), 23 (IC50 = 12.5 ± 3.1 μM), 27 (IC50 = 32.8 ± 1.1 μM), 39 (IC50 = 20.2 ± 1.6 μM), and 42 (IC50 = 43.2 ± 3.8 μM) showed potent ROS inhibition as compared to standard ibuprofen (IC50 = 54.3 ± 1.9 μM). Whereas, compounds 3 (IC50 = 134.7 ± 1.0 μM), 16 (IC50 = 75.4 ± 7.2 μM), 24 (IC50 = 102.4 ± 1.0 μM), and 31 (IC50 = 86.6 ± 1.5 μM) were found to be moderately active. Compounds 1, 2, 5, 23, 27, 39, and 42, having potent ROS inhibitory activity were also screened for their nitric oxide (NO) inhibition. Cytotoxicity was also checked for all active compounds on NIH-3T3 cell line. Cyclohexamide (IC50 = 0.13 ± 0.02 μM) was used as standard.

Conclusion:

Identified active compounds from these libraries may serve as lead candidates for future research in order to obtain a more potent, and safer anti-inflammatory agent.

Anti-proliferative and immunomodulatory activities of fractions from methanol root extract of Abrus precatorius L

Background

Abrus precatorius possesses various therapeutic properties including anticancer potentials. This study evaluated the anti-proliferative activities of fractions of methanol root extract of A. precatorius on breast and cervical cancer cells and their immunomodulatory effect. Phytochemical screening was done by FTIR and GCMS. In vitro anti-proliferative effect was evaluated on human breast cancer (AU565) and cervical cancer (HeLa) cells and on murine fibroblast (NIH 3 T3) cells. Antioxidant activity was performed via DPPH radical scavenging assay. The immunomodulatory potential of fractions was evaluated by inhibition of phagocytes oxidative burst (ROS), Nitric oxide (NO) and proinflammatory cytokine TNF-α.

Results

A. precatorius fractions showed different chemical groups and were somewhat selective in antiproliferative activity against studied cancer cells. Ethyl acetate fraction showed the most significant antiproliferative activity with IC50 values of 18.10 μg/mL and 11.89 μg/mL against AU565 and HeLa cells respectively. Hexane fraction significantly (p < 0.05) inhibited HeLa cells (IC50 18.24 ± 0.16 μg/mL), whereas aqueous fraction showed mild inhibition (IC50 46.46 ± 0.14 μg/mL) on AU565 cell proliferation. All fractions showed no cytotoxicity against NIH-3 T3 murine fibroblast normal cells. All fractions showed potent and significant (p < 0.001) DPPH radical scavenging activity as well as suppressed phagocytic oxidative burst. Hexane (< 1 μg/mL), ethyl acetate (< 1 μg/mL), and butanol (5.74 μg/mL) fractions potently inhibited the cytokine TNF- α, hexane (< 1 μg/mL) and ethyl acetate (< 1 μg/mL) fractions also potently inhibited NO.

Conclusions

The antiproliferative activities and suppressive effect on the phagocytic oxidative burst, NO and proinflammatory cytokine might be due to the synergistic actions of bioactive compounds especially flavonoids present in the assayed fractions and therefore, suggest chemotherapeutic use of A. precatorius in cancer treatment.

A Review Exploring Therapeutic Worth of 1,3,4-Oxadiazole Tailored Compounds

1,3,4-Oxadiazole, a five-membered aromatic ring can be seen in a number of synthetic molecules. The peculiar structural feature of 1,3,4-oxadiazole ring with pyridine type of nitrogen atom is beneficial for 1,3,4-oxadiazole derivatives to have effective binding with different enzymes and receptors in biological systems through numerous weak interactions, thereby eliciting an array of bioactivities. Research in the area of development of 1,3,4-oxadiazole-based derivatives has become an interesting topic for the scientists. A number of 1,3,4-oxadiazole based compounds with high therapeutic potency are being extensively used for the treatment of different ailments, contributing to enormous development value. This work provides a systematic and comprehensive review highlighting current developments of 1,3,4-oxadiazole based compounds in the entire range of medicinal chemistry such as anticancer, antifungal, antibacterial, antitubercular, anti-inflammatory, antineuropathic, antihypertensive, antihistaminic, antiparasitic, antiobesity, antiviral, and other medicinal agents. It is believed that this review will be of great help for new thoughts in the pursuit for rational designs for the development of more active and less toxic 1,3,4-oxadiazole based medicinal agents.

Sulphamethazine derivatives as immunomodulating agents: New therapeutic strategies for inflammatory diseases

Sulfamethazine (SMZ) (1) is an antibacterial sulfa drug which suppresses the synthesis of dihydrofolic acid. It is used for the treatment of infections in livestock; such as gastrointestinal, and respiratory tract infections. During the current study, synthesis, characterization, and evaluation of immunomodulatory activities of derivatives of sulfamethazine (SMZ) (3-39) was carried out. These derivatives were synthesized by the reaction of sulfamethazine with a range of acid chlorides. All the compounds were characterized by using modern spectroscopic techniques, such as 1H-, and 13C-NMR, EI-MS, and HRFAB-MS. Compounds 3-10, 14, and 15 were identified as new compounds. Immunomodulatory effect of compounds 3-39 on different parameters of innate immune response was evaluated, including the production of Reactive Oxygen Species (ROS) from human whole blood and isolated polymorphonuclear neutrophils (PMNs), nitric oxide (NO), and pro-inflammatory cytokine TNF-α. All the new compounds, except 14 and 15, showed a significant anti-inflammatory activity. Compounds 3-39 were also evaluated for their anti-bacterial activity and cytotoxicity (3T3 mouse fibroblast cell lines). All the compounds were found to be non-cytotoxic against normal cell lines.

Benzophenone Esters and Sulfonates: Synthesis and their Potential as Antiinflammatory Agents

BACKGROUND

Inflammation is a biological rejoinder of vascular tissues against destructive agents e.g. irritants, damaged cell or pathogens. During inflammation, respiratory burst occurs by activated phagocytes which help to destroy invading pathogens. Phagocytic cells such as neutrophils and macrophages are one of the major sources of reactive oxygen species (ROS) and nitric oxide (NO). Normally, the redox environment is maintained by various antioxidant defense systems, however, these reactive oxygen species may be destructive and can lead to various pathological conditions.

METHODS

Benzophenone esters and sulfonates (1-18) were synthesized through one pot synthesis by reacting 4-hydroxy benzophenone either different benzoyl chloride or sulfonyl chloride. These synthetic compounds were evaluated for their in vitro immunosuppressive potential on two parameters of innate immune response including inhibition of intracellular reactive oxygen species (ROS) and nitric oxide (NO). ROS were induced in polymorphonuclear leukocytes (PMNs) isolated from human whole blood by serum opsonized zymosan stimulation, whereas NO were produced in J774.2 cells by lipopolysachharides (LPS) stimulation. Moreover, cytotoxicity of compounds was also determined using NIH-3T3 fibroblast cells (ATCC, Manassas, USA) was evaluated by using the standard MTT colorimetric assay.

RESULTS

All compounds inhibited the production of ROS at various extent among which compounds 2, 5, 6, 8, 10, 13 and 16 were found to be the potent inhibitors of ROS with IC50 values ranging between (1.0 - 2.2 µg/mL) as compared to ibuprofen (IC50 = 2.5 ± 0.6 µg/mL) as the standard drug. Compounds 2, 7, 11, 13, 14 and 18 showed good inhibition of NO production with % inhibition values ranging between (63.6% - 76.7%) at concentration of 25 µg/mL as compared to NG-monomethyl-Larginine (L-NMMA 65.6 ± 1.1 µg/mL) as the standard. All other derivatives showed moderate to low level of inhibition on both tested parameters. Cytotoxicity activity also showed nontoxicity of synthetic compounds. Structures of all the synthetic compounds were confirmed through 1H-NMR, 13C-NMR, EI-MS and HREI-MS spectroscopic techniques.

CONCLUSION

Compounds 2 and 13 were found to be good dual antiinflammatory (ROS and NO) agent. However, compounds 5, 6, 8, 10 and 16 were found to be selectively active for ROS inhibitory studies. Compounds 7, 11, 14 and 18 were discriminatory active at NO inhibition assay. These initial findings of antiinflammatory activity concluded that these compounds might have the potential to develop a novel non-steroidal antiinflammatory drugs (NSAIDs), non-acidic antiinflammatory agent. Most active compounds 2, 5-8, 10, 13, 14 and 16 showed nontoxicity of synthetic compounds.

Biotransformation of anabolic compound methasterone with Macrophomina phaseolina, Cunninghamella blakesleeana, and Fusarium lini, and TNF-α inhibitory effect of transformed products

Microbial transformation of methasterone (1) was investigated with Macrophomina phaseolina, Cunninghamella blakesleeana, and Fusarium lini. Biotransformation of 1 with M. phaseolina yielded metabolite 2, while metabolites 3-7 were obtained from the incubation of 1 with C. blakesleeana. Metabolites 8-13 were obtained through biotransformation with F. lini. All metabolites, except 13, were found to be new. Methasterone (1) and its metabolites 2-6, 9, 10, and 13 were then evaluated for their immunomodulatory effects against TNF-α, NO, and ROS production. Among all tested compounds, metabolite 6 showed a potent inhibition of proinflammatory cytokine TNF-α (IC₅₀=8.1±0.9μg/mL), as compared to pentoxifylline used as a standard (IC₅₀=94.8±2.1μg/mL). All metabolites were also evaluated for the inhibition of NO production at concentration of 25μg/mL. Metabolites 6 (86.7±2.3%) and 13 (62.5±1.5%) were found to be the most potent inhibitors of NO as compared to the standard N^G-monomethyl-l-arginine acetate (65.6±1.1%). All metabolites were found to be non-toxic against PC3, HeLa, and 3T3 cell lines. Observed inhibitory potential of metabolites 6 and 13 against pro-inflammatory cytokine TNF-α, as well as NO production makes them interesting leads for further studies.

Synthesis of New Functionalized Indoles Based on Ethyl Indol-2-carboxylate

Successful alkylations of the nitrogen of ethyl indol-2-carboxylate were carried out using aq. KOH in acetone. The respective N-alkylated acids could be obtained without separating the N-alkylated esters by increasing the amount of KOH and water. The use of NaOMe in methanol led to transesterification instead of the alkylation, while the use of NaOEt led to low yields of the N-alkylated acids. Hydrazinolysis of the ester gave indol-2-carbohydrazide which then was allowed to react with different aromatic aldehydes and ketones in ethanol catalyzed by acetic acid. Indol-2-thiosemicarbazide was used in a heterocyclization reaction to form thiazoles. The new structures were confirmed using NMR, mass spectrometry and X-ray single crystal analysis.

Anti-inflammatory Steroidal Alkaloids from Sarcococca wallichii of Nepalese Origin

Bio-assay guided isolation from the plant Sarcococca wallichii Staph. yielded two new steroidal alkaloids: wallichimine A (1) and wallichimine B (2), and five known ones: sarcodinine (3), N-methylpachysamine A (4), alkaloid C (5), dictyophlebine (6), and sarcorine (7). The structures of the compounds were determined using mass spectrometry and NMR spectroscopy techniques. The immunomodulatory potential of compounds was evaluated on different parameters including production of intracellular reactive oxygen species (ROS), nitric oxide (NO) and on proinflammatory cytokine TNF-α. All compounds were found to be potent inhibitors of intracellular ROS produced from isolated neutrophils, except compound 5, which showed a moderate level of inhibition. Compounds 2 and 4 potently inhibited the production of NO (67.9% and 62.5% respectively). Compound 2 showed potent suppression on production of proinflammatory cytokine TNF-α (76.7%). Among all the tested compounds the new compound 2 was found to be the most potent immunosuppressive agent. This study shows that steroidal alkaloids could be lead compounds for anti-inflammatory drug discovery.

New inhibitors of ROS generation and T-cell proliferation from Myrtus communis

Phytochemical investigation on Myrtus communis Linn. afforded myrtucommuacetalone (1) with an unprecedented carbon skeleton and a new phloroglucinol-type compound, myrtucommulone M (2), along with four known constituents 3-6. Their structures were established by extensive analyses of NMR and mass spectral data as well as by single-crystal X-ray diffraction studies. These constituents were evaluated for their ability to modulate the immune response, based on their effects on various components of immune system. Compounds 1 and 5 exhibited significant inhibitory effect against nitric oxide (NO(•)) production. Compound 1 also exhibited significant antiproliferative activity (IC50 < 0.5 μg/mL) against T-cell proliferation. Myricetin (3) exerted a significant inhibition (IC50 = 1.6 μg/mL) on zymosan-stimulated whole blood phagocytes ROS production. Compounds 1 and 3 were active against PMA-stimulated ROS generation.