Anti-inflammatory phenylpropanoid glycosides from the fruits of Forsythia suspensa

Five new phenylpropanoid glycosides, susaroysides A–E (1–5) were isolated from the fruits of Forsythia suspensa. Their structures were elucidated by comprehensive spectroscopic data analysis. The absolute configurations of their sugars were determined by GC analysis. Notably, susaroysides A–D possessed a sugar with an unsubstituted anomeric carbon, which is relatively rare in natural sources. Compound 1 exhibited significant anti-inflammatory activity against the lipopolysaccharide (LPS)-induced tumor necrosis factor (TNF)-α expression in macrophage cells with the IC₅₀ value of 1.053 μM.     

Design and synthesis of the novel oleanolic acid-cinnamic acid ester derivatives and glycyrrhetinic acid-cinnamic acid ester derivatives with cytotoxic properties

Oleanolic acid (OA) and glycyrrhetinic acid (GA) are natural products with anticancer effects. Cinnamic acid (CA) and its derivatives also exhibited certain anticancer activity. In order to improve the anticancer activity of OA and GA, we designed and synthesized a series of novel OA-CA ester derivatives and GA-CA ester derivatives by using molecular hybridization approach. The 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was used to assess their in vitro cytotoxicity on three cell lines (HeLa (cervical cancer), MCF-7 (breast cancer) and L-O2 (a normal hepatic cell)). Among the evaluated compounds, 3o presented the strongest selective cytotoxicity on HeLa cells (IC₅₀ = 1.35 μM) and showed no inhibitory activity against MCF-7 cells (IC₅₀ > 100 μM) and L-O2 cells (IC₅₀ > 100 μM), and 3e presented the strongest selective inhibition of the MCF-7 cells (IC₅₀ = 1.79 μM). What’s more, compound 2d also showed very strong selective inhibitory activity against HeLa cells (IC₅₀ = 1.55 μM). The further research using Hoechst 33342, AO/EB dual-staining, flow cytometric analysis and DCFH-DA fluorescent dye staining assay presented that 2d and 3o could induce HeLa cells apoptosis and autophagy.     

Click chemistry based multicomponent approach in the synthesis of spirochromenocarbazole tethered 1,2,3-triazoles as potential anticancer agents

A series of spirochromenocarbazole tethered 1,2,3-triazoles were synthesized via click chemistry based one-pot, five component reaction between N-propargyl isatins, malononitrile, 4-hydroxycarbazole, aralkyl halides and sodium azide using cellulose supported CuI nanoparticles (Cell-CuI NPs) as the heterogeneous catalyst. Antiproliferative activity of all the synthesized compounds was investigated against panel of cancer cell lines such as MCF-7, MDA-MB-231, HeLa, PANC-1, A-549, and THP-1. Many of the synthesized compounds exhibited good anti-proliferative activity against breast (MCF-7 and MDA-MB-231) and cervical (HeLa) cancer cells with IC₅₀ values less than 10 μM. In case of MCF-7 cells, among the nine compounds that showed good anti-proliferative activity, compounds 6f and 6j were found to be highly potent (IC₅₀ = 2.13 μM and 4.80 μM, respectively). In case of MDA-MB-231, three compounds (6k, 6j and 6s) showed antiproliferative activity amongst which 6k was the most potent one (IC₅₀ = 3.78 μM). On the other hand, in cervical cancer HeLa cells, compounds 6b, 6g, 6s and 6u showed excellent antiproliferative activity (IC₅₀ = 4.05, 3.54, 3.83, 3.35 μM, respectively). All the compounds were found to be nontoxic to the human umbilical vein endothelial cells (HUVECs). AO and EtBr staining and fluorescence microscopy studies of the active compounds (IC₅₀ < 5 μM) suggested that these compounds induce cell death by apoptosis.     

Novel benzothiazole hydrazine carboxamide hybrid scaffolds as potential in vitro GABA AT enzyme inhibitors: Synthesis,molecular docking and antiepileptic evaluation

In the present study, a series of newer benzothiazole derivatives containing thiazolidin-4-one (5a-g) and azetidin-2-one (6a-g), were synthesized by the cyclization of benzothiazolyl arylidene hydrazine carboxamide derivatives with thioglycolic acid and chloroacetyl chloride, respectively. Results of in vivo anticonvulsant screening revealed that compounds having 2,4-dicholoro (5c and 6c) and 4-nitro substituent (5g) at the phenyl ring have promising anticonvulsant activities without any neurotoxicity. Selected compounds were also evaluated for their in vitro GABA AT inhibition. The results indicated that compound 5c (IC₅₀ 15.26 μM) exhibited excellent activity as compared to the standard drug vigabatrin (IC₅₀ 39.72 μM) suggesting the potential of these benzothiazole analogues as new anticonvulsant agents.     

Novel pyridazinone derivatives as butyrylcholinesterase inhibitors

In the current study, forty-four new [3-(2/3/4-methoxyphenyl)-6-oxopyridazin-1(6H)-yl]methyl carbamate derivatives were synthesized and evaluated for their ability to inhibit electric eel acetylcholinesterase (EeAChE) and equine butyrylcholinesterase (eqBuChE) enzymes. According to the inhibitory activity results, [3-(2-methoxyphenyl)-6-oxopyridazin-1(6H)-yl]methyl heptylcarbamate (16c, eqBuChE, IC₅₀ = 12.8 μM; EeAChE, no inhibition at 100 μM) was the most potent eqBuChE inhibitor among the synthesized compounds and was found to be a moderate inhibitor compared to donepezil (eqBuChE, IC₅₀ = 3.25 μM; EeAChE, IC₅₀ = 0.11 μM). Kinetic and molecular docking studies indicated that compounds 16c and 14c (hexylcarbamate derivative, eqBuChE, IC₅₀ = 35 μM; EeAChE, no inhibition at 100 μM) were mixed-type inhibitors which accommodated within the catalytic active site (CAS) and peripheral anionic site (PAS) of hBuChE through stable hydrogen bonding and π-π stacking. Furthermore, it was determined that [3-(2-methoxyphenyl)-6-oxopyridazin-1(6H)-yl]methyl (4-methylphenyl)carbamate 7c (eqBuChE, IC₅₀ = 34.5 μM; EeAChE, 38.9% inhibition at 100 μM) was the most active derivative against EeAChE and a competitive inhibitor binding to the CAS of hBuChE. As a result, 6-(2-methoxyphenyl)pyridazin-3(2H)-one scaffold is important for the inhibitory activity and compounds 7c, 14c and 16c might be considered as promising lead candidates for the design and development of selective BuChE inhibitors for Alzheimer’s disease treatment.     

New derivatives of ursolic acid through the biotransformation by Bacillus megaterium CGMCC 1.1741 as inhibitors on nitric oxide production

Microbial transformation of ursolic acid (1) by Bacillus megaterium CGMCC 1.1741 was investigated and yielded five metabolites identified as 3-oxo-urs-12-en-28-oic acid (2); 1β,11α-dihydroxy-3-oxo-urs-12-en-28-oic acid (3); 1β-hydroxy-3-oxo-urs-12-en-28, 13-lactoe (4); 1β,3β, 11α-trihydroxyurs-12-en-28-oic acid (5) and 1β,11α-dihydroxy-3-oxo-urs-12-en-28-O-β-d-glucopyranoside (6). Metabolites 3, 4, 5 and 6 were new natural products. Their nitric oxide (NO) production inhibitory activity was assessed in lipopolysaccharide (LPS) – stimulated RAW 264.7 cells. Compounds 3 and 4 exhibited significant activities with the IC₅₀ values of 1.243 and 1.711 μM, respectively. A primary structure-activity relationship was also discussed.     

Synthesis and urease inhibitory potential of benzophenone sulfonamide hybrid in vitro and in silico

This study deals with the synthesis of benzophenone sulfonamides hybrids (1–31) and screening against urease enzyme in vitro. Studies showed that several synthetic compounds were found to have good urease enzyme inhibitory activity. Compounds 1 (N′-((4′-hydroxyphenyl)(phenyl)methylene)-4′′-nitrobenzenesulfonohydrazide), 2 (N′-((4′-hydroxyphenyl)(phenyl)methylene)-3′′-nitrobenzenesulfonohydrazide), 3 (N′-((4′-hydroxyphenyl)(phenyl)methylene)-4′′-methoxybenzenesulfonohydrazide), 4 (3′′,5′′-dichloro-2′′-hydroxy-N′-((4′-hydroxyphenyl)(phenyl)methylene)benzenesulfonohydrazide), 6 (2′′,4′′-dichloro-N′-((4′-hydroxyphenyl)(phenyl)methylene)benzenesulfonohydrazide), 8 (5-(dimethylamino)-N′-((4-hydroxyphenyl)(phenyl)methylene)naphthalene-1-sulfono hydrazide), 10 (2′′-chloro-N′-((4′-hydroxyphenyl)(phenyl)methylene)benzenesulfonohydrazide), 12 (N′-((4′-hydroxyphenyl)(phenyl)methylene)benzenesulfonohydrazide) have found to be potently active having an IC₅₀ value in the range of 3.90–17.99?µM. These compounds showed superior activity than standard acetohydroxamic acid (IC₅₀?=?29.20?±?1.01?µM). Moreover, in silico studies on most active compounds were also performed to understand the binding interaction of most active compounds with active sites of urease enzyme. Structures of all the synthetic compounds were elucidated by ¹H NMR, ¹³C NMR, EI-MS and FAB-MS spectroscopic techniques.     

Design,synthesis and evaluation of d-amino acid-containing peptidomimetics targeting the polo-box domain of polo-like kinase 1

A series of d-amino acid-containing peptidomimetics were designed, synthesized as novel polo-like kinase 1 (Plk1) polo-box domain (PBD) inhibitors based on the reported peptide Plk1 PBD inhibitor. Their inhibitory activity to Plk1, Plk2, and Plk3 PBD were evaluated using our fluorescence polarization (FP) assay. Compound 18 bound to Plk1 PBD with IC₅₀ of 0.80 μM and showed nearly no inhibition to Plk2 PBD or Plk3 PBD at 100 μM. Compound 18 induced Hela cells to undergo apoptosis by increasing the ratio of the cells at the G2/M phase by decreasing the neosynthesized proteins in a dose-dependent manner from 50 to 150 μM. Compound 18 showed improved stability in rat plasma compared to l-peptide inhibitor LHSpTA. These novel d-amino acid modified selective Plk1 PBD inhibitors may provide new lead compounds for further optimization.     

Bioassay-guided fractionation of Euphrasia pectinata Ten. and isolation of iridoids with antiproliferative activity

The use of aerial parts of Euphrasia pectinata Ten. usually known as Eyebright, is one of the commonest folk remedy in many European and Asian countries to treat eye problems. By a bioassay-guided fractionation of the dichloromethane fraction of E. pectinata methanolic extract, following the antiproliferative activity on different cancer cell lines (MCF-7, HeLa, LNCaP, ACHN and C32), the new iridoid euphrasin (1), and the known campsinol (2), artselaenin A (3), and artselaenin B (4) were isolated. The structure of euphrasin (1) was determined by spectroscopic methods. All compounds screened by SRB assay exhibited antiproliferative activity in a concentration dependent-manner. In particular, euphrasin (1) showed a promising activity against LNCaP and HeLa cells with IC50 values of 0.1 and 0.2 μM, respectively. Signficative results were also obtained with campsinol (2) with IC50 value of 1.9 μM on endometrial cancer cells.     

Synthesis,antitumor testing and molecular modeling study of some new 6-substituted amido,azo or thioureido-quinazolin-4(3H)-ones

A new series of 6-substituted amido, azo or thioureido-quinazolin-4(3H)-one was synthesized and tested for their in-vitro antitumor activity. Compounds 21, 53 and 60 showed broad spectrum antitumor activity with average IC₅₀ values of 6.7, 7.6 and 9.1 μM, respectively compared with methotrexate (1, IC₅₀ 19.26 μM). As an attempt to reveal the mechanism of the antitumor potency, cell cycle analysis and DHFR inhibition were performed. Compounds 59 and 61 induced their cytotoxicity in Hela (IC₅₀ 10.6 μM) and HCT-116 (IC₅₀ 15.5 μM) cell lines, respectively through Pre-G1 apoptosis, inhibiting cell growth at G2-M phase. Compounds 29, 33, 59 and 61 showed DHFR inhibitory potency at IC₅₀ 0.2, 0.2, 0.3 and 0.3 μM, respectively. The active DHFR inhibitors showed high affinity binding toward the amino acid residues Thr56, Ser59 and Ser118. The active compounds obeyed Lipinski’s rule of five and could be used as template model for further optimization.     

Design,synthesis, and biological evaluation of 2-amino-N-(2-methoxyphenyl)-6-((4-nitrophenyl)sulfonyl)benzamide derivatives as potent HIV-1 Vif inhibitors

Viral infectivity factor (Vif) is one of the accessory protein of human immunodeficiency virus type I (HIV-1) that inhibits host defense factor, APOBEC3G (A3G), mediated viral cDNA hypermutations. Previous work developed a novel Vif inhibitor 2-amino-N-(2-methoxyphenyl)-6-((4-nitrophenyl)thio)benzamide (1) with strong antiviral activity. Through optimizations on the two side branches, a series of compound 1 derivatives (2–18) were designed, synthesized and tested in vitro for their antiviral activities. The biological results showed that compound 5 and 16 inhibited the virus replication efficiently with EC₅₀ values of 9.81 and 4.62 μM. Meanwhile, low cytotoxicities on H9 cells were observed for the generated compounds by the MTT assay. The structure–activity relationship of compound 1 was preliminarily clarified, which gave rise to the development of more potent Vif inhibitors.     

Design,synthesis and biological evaluation of novel inhibitors against cyanobacterial pyruvate dehydrogenase multienzyme complex E1

Cyanobacterial pyruvate dehydrogenase multienzyme complex E1 (PDHc E1) is a potential target enzyme for finding inhibitors to control harmful cyanobacterial blooms. In this study, a series of novel triazole thiamin diphosphate (ThDP) analogs were designed and synthesized by modifying the substituent group of triazole ring and optimizing triazole-benzene linker as potential cyanobacterial PDHc E1 (Cy-PDHc E1) inhibitors. Their inhibitory activities against Cy-PDHc E1 in vitro and algicide activities in vivo were further examined. Most of these compounds exhibited prominent inhibitory activities against Cy-PDHc E1 (IC₅₀ 1.48–4.48 μM) and good algicide activities against Synechocystis PCC6803 (EC₅₀ 0.84–2.44 µM) and Microcystis aeruginosa FACHB905 (EC₅₀ 0.74–1.77 µM). Especially, compound 8d showed not only the highest inhibitory activity against Cy-PDHc E1 (IC₅₀ 1.48 μM), but also the most powerful inhibitory selectivity between Cy-PDHc E1 (inhibitory rate 98.90%) and porcine PDHc E1 (inhibitory rate only 9.54%). Furthermore, the potential interaction between compound 8d and Cy-PDHc E1 was analyzed by a molecular docking method and site-directed mutagenesis and enzymatic analysis and fluorescence spectral analysis. These results indicated that compound 8d could be used as a hit compound for further optimization and might have potential to be developed as a new algicide.     

2,5-Disubstituted thiadiazoles as potent β-glucuronidase inhibitors; Synthesis,in vitro and in silico studies

Twenty-five thiadiazole derivatives 1–25 were synthesized from methyl 4-methoxybenzoate via hydrazide and thio-hydrazide intermediates, and evaluated for their potential against β-glucuronidase enzyme. Most of the compounds including 1 (IC₅₀ = 26.05 ± 0.60 μM), 2 (IC₅₀ = 42.53 ± 0.80 μM), 4 (IC₅₀ = 38.74 ± 0.70 μM), 5 (IC₅₀ = 9.30 ± 0.29 μM), 6 (IC₅₀ = 6.74 ± 0.26 μM), 7 (IC₅₀ = 18.40 ± 0.66 μM), and 15 (IC₅₀ = 18.10 ± 0.53 μM) exhibited superior activity potential than the standard d-saccharic acid-1,4-lactone (IC₅₀ = 48.4 ± 1.25 μM). Molecular docking studies were conducted to correlate the in vitro results and to identify possible mode of interaction with enzyme active site.     

Structure-activity relationships study of neolamellarin A and its analogues as hypoxia inducible factor-1 (HIF-1) inhibitors

The novel marine pyrrole alkaloid neolamellarin A derived from sponge has been shown to inhibit hypoxia-induced HIF-1 activity. In this work, we designed and synthesized neolamellarin A and its series of derivatives by a convergent synthetic strategy. The HIF-1 inhibitory activity and cytotoxicity of these compounds were evaluated in Hela cells by dual-luciferase reporter gene assay and MTT assay, respectively. The results showed that neolamellarin A 1 (IC₅₀ = 10.8 ± 1.0 μM) and derivative 2b (IC₅₀ = 11.9 ± 3.6 μM) had the best HIF-1 inhibitory activity and low cytotoxicity. Our SAR research focused on the effects of key regions aliphatic carbon chain length, aromatic ring substituents and C-7 substituent on biological activity, providing a basis for the subsequent research on the development of novel pyrrole alkaloids as HIF-1 inhibitors and design of small molecule probes for target protein identification.     

Design,synthesis and biological evaluation of novel dithiocarbamate-substituted diphenylaminopyrimidine derivatives as BTK inhibitors

Bruton’s tyrosine kinase (BTK) has emerged as an attractive target related to B-lymphocytes dysfunctions, especially hematologic malignancies and autoimmune diseases. In our study, a series of diphenylaminopyrimidine derivatives bearing dithiocarbamate moieties were designed and synthesized as novel BTK inhibitors for treatment of B-cell lymphoma. Among all these compounds, 30ab (IC₅₀ = 1.15 ± 0.19 nM) displays similar or more potent inhibitory activity against BTK than spebrutinib (IC₅₀ = 2.12 ± 0.32 nM) and FDA approved drug ibrutinib (IC₅₀ = 3.89 ± 0.57 nM), which is attributed to close binding of 30ab with BTK predicted by molecular docking. In particular, 30ab exhibits enhanced anti-proliferative activity against B-lymphoma cell lines at the IC₅₀ concentration of 0.357 ± 0.02 μM (Ramos) and 0.706 ± 0.05 μM (Raji), respectively, almost 10-fold better than ibrutinib and spebrutinib. In addition, 30ab displays stronger selectivity on B-cell lymphoma over other cancer cell lines than spebrutinib. Furthermore, 30ab efficiently blocks BTK downstream pathways and results in apoptosis of cancer cells. In vivo xenograft model evaluation demonstrates the significant efficacy and broad safety margin of 30ab in treatment of B-cell lymphoma. We propose that compound 30ab is a candidate for further study and development based on our current findings.     

Antimicrobial effects of N-benzyloxycarbonyl-S-(2,4-dinitrophenyl) glutathione diesters against chloroquinine sensitive (NF54) and resistant (K1) strains of Plasmodium falciparum

N-Benzyloxycarbony-S-(2,4-dinitrophenyl)glutathione diesters have been investigated for antimalarial activity against chloroquinine sensitive (NF54) and resistant (K1) strains of P. falciparum. Both strains appear equally susceptible to inhibition by compounds 1–4, with an IC₅₀ ∼ 4.92–6.97 μM, consistent with the target of these compounds being the PfMRP transporter. Against the NF54 strain, diester derivatives containing ethyl side chains showed lower in vitro activity than those with methyl side chains 1–4, IC₅₀ ∼ 5.7–6.97 μM with the exception of compound 5 (IC₅₀ > 25 μM). The cytotoxicity of compounds with log P ∼ 3.9–5.8 were lower against the murine L6 cell line than compounds with a higher log P > 5.8 that were toxic. Overall the cytotoxicity of compounds 1–7 were lower against KB cells than against the L6 cell line with the exception of compound 4, which showed a higher relative toxicity.     

Antiplasmodial and cytotoxic activity of lanostane type triterpenoids isolated from Leplaea mayombensis

Leplaeric acid E 5, leplazarin 6a and 21-epileplazarin 6b, three new 3,4-seco-lanostane type triterpenes have been isolated from the stem bark of Leplaea mayombensis (Pellegr.) Staner along with fourteen known compounds from the fruits and roots. Leplaeric acid E, leplazarin and 21-epileplazarin, 15-α-hydroxy-3,4-seco-lanosta-4(28),8,24-triene-3,21-dioic acid, mayomlactones A and B, lanosta-7,24-dien-3-one, leplaeric acid A, B and C were screened in vitro for antiplasmodial activity against chloroquine-sensitive (Pf3D7) and chloroquine-resistant (PfINDO) strains of Plasmodium falciparum and for cytotoxicity against CAL-27, CaCo2, Skov-3, and HepG2 cells line. Three compounds including 15-α-hydroxy-3,4-seco-lanosta-4(28),8,24-triene-3,21-dioic acid (IC₅₀ 5.65–7.09 μM), lanosta-7,24-dien-3-one (IC₅₀ 7.18–9.07 μM), and leplaeric acid C (IC₅₀ 7.59–8.47 μM) were the most active against both strains of P. falciparum. All the compounds exhibited cytotoxicity against the three-cell lines with IC₅₀ ranging from 12.30 to 181.88 μM. These results confirm the usage of the medicinal plant L. mayombensis for the management of malaria and suggest that further lead optimization studies on potent compounds identified from this study could lead to the identification of potential of lead molecules as scaffold for new antimalarial drug discovery.     

Design,synthesis and biological evaluation of fused naphthofuro[3,2-c] quinoline-6,7,12-triones and pyrano[3,2-c]quinoline-6,7,8,13-tetraones derivatives as ERK inhibitors with efficacy in BRAF-mutant melanoma

Approximately 60% of human cancers exhibit enhanced activity of ERK1 and ERK2, reflecting their multiple roles in tumor initiation and progression. Acquired drug resistance, especially mechanisms associated with the reactivation of the MAPK (RAF/MEK/ERK) pathway represent a major challenge to current treatments of melanoma and several other cancers. Recently, targeting ERK has evolved as a potentially attractive strategy to overcome this resistance. Herein, we report the design and synthesis of novel series of fused naphthofuro[3,2-c]quinoline-6,7,12-triones 3a-f and pyrano[3,2-c]quinoline-6,7,8,13-tetraones 5a,b and 6, as potential ERK inhibitors. New inhibitors were synthesized and identified by different spectroscopic techniques and X-ray crystallography. They were evaluated for their ability to inhibit ERK1/2 in an in vitro radioactive kinase assay. 3b and 6 inhibited ERK1 with IC50s of 0.5 and 0.19 µM, and inhibited ERK2 with IC50s of 0.6 and 0.16 µM respectively. Kinetic mechanism studies revealed that the inhibitors are ATP-competitive inhibitors where 6 inhibited ERK2 with a K_i of 0.09 µM. Six of the new inhibitors were tested for their in vitro anticancer activity against the NCI-60 panel of tumor cell lines. Compound 3b and 6 were the most potent against most of the human tumor cell lines tested. Moreover, 3b and 6 inhibited the proliferation of the BRAF mutant A375 melanoma cells with IC50s of 3.7 and 0.13 µM, respectively. In addition, they suppressed anchorage-dependent colony formation. Treatment of the A375 cell line with 3b and 6 inhibited the phosphorylation of ERK substrates p-90RSK and ELK-1 and induced apoptosis in a dose dependent manner. Finally, a molecular docking study showed the potential binding mode of 3b and 6 within the ATP catalytic binding site of ERK2.     

Neuraminidase inhibitory activities of flavonols isolated from Rhodiola rosea roots and their in vitro anti-influenza viral activities

Five flavonols (3, 5, and 9–11) were isolated from Rhodiola rosea, and compared with commercially available flavonoids (1, 2, 4, 6–8, and 12–14) to facilitate analysis of their structure–activity relationship (SAR). All compounds (1–14) showed neuraminidase inhibitory activities with IC₅₀ values ranging from 0.8 to 56.9 μM. The in vitro anti-influenza virus activities of flavonoids 1–6, 8–12, and 14 were evaluated using two influenza viral strains, H1N1 (A/PR/8/34) and H9N2 (A/Chicken/Korea/MS96/96), testing their ability to reduce virus-induced cytopathic effect (CPE) in MDCK cells. We found that the activity of these compounds ranged from 30.2 to 99.1 μM against H1N1- and 18.5 to 133.6 μM against H9N2-induced CPE. Of compounds 1–14, gossypetin (6) exhibited the most potent inhibitory activity, with IC₅₀ values of 0.8 and 2.6 μM on neuraminidases from Clostridium perfringens and recombinant influenza virus A (rvH1N1), respectively. In contrast, kaempferol (3) exhibited the highest activity against two influenza viruses, H1N1 and H9N2 with EC₅₀ values of 30.2 and 18.5 μM, respectively. Activity depended on the position and number of hydroxy groups on the flavonoids backbone. In kinetic studies, all isolated compounds behaved as noncompetitive inhibitors.     

Synthesis and biological evaluation of 7-methoxy-1-(3,4,5-trimethoxyphenyl)-4,5-dihydro-2H-benzo[e]indazoles as new colchicine site inhibitors

The colchicine site inhibitors (CSIs) displayed both antimitotic and vascular disrupting activities, therefore are promising potential antitumor agents. In this study, a series 1-phenyl-4,5-dihydro-2H-benzo[e]indazoles were found as new CSIs of which the bioactive configuration was locked. Among them, compounds C1 and C2 displayed the best activity, with tubulin polymerization IC₅₀ of 3.4 and 1.5 μM, and growth IC50 of low nanomolar concentrations against human colon cancer cell lines. In addition, compound C1 showed excellent broad-spectrum antitumor activity in the NCI-60 Human Tumor Cell Lines Screen, encouraging further study of this antitumor compound.