Repellent and Insecticidal Activity of Naphthoquinones from the Heartwood of Tectona grandis on Incisitermes marginipennis(Latreille)

Wood is a lignocellulosic material that,because of its organic nature,is a source of nutrients for bacteria,fungi,and insects.Incisitermes marginipennis(Latreille)is an interesting dry wood-boring termite.Because it is an extremely destructive pest,difficult to control due to its cryptic lifestyle,and for its role in the biogeochemical cycle of carbon and other elements;it is a fundamental organism.The use of less toxic and eco-friendly substances is important for protecting domestic,cultural,and historical heritage made of wood or lignocellulosic materials.The aim of this study was to evaluate the biological activity of various naphthoquinones extracted from the heartwood of T.grandis on I.marginipennis.First,heartwood flour was used for Soxhlet-type extractions to isolate and characterize the heartwood compounds by thin-layer chromatography.To identify the heartwood compounds,nuclear magnetic resonance and gas chromatography coupled to a mass spectrometer were used.The information obtained was supported using the Interactive Spectroscopy software.The identified heartwood compounds were lapachol,tectoquinone,deoxylapachol,dehydro-α-lapachone,tectol and tecomaquinone-I.Using nymphal termites of I.marginipennis as a biological model,the isolated and identified molecules were under three different tests(repellent,insecticide and protective)and their biological activity was individually evaluated.The results showed that the molecules obtained have a repellent-protective effect against I.marginipennis,although not in all cases,these molecules have high percentages of mortality and decreased the weight loss of the treated material exposed to I.marginipennis.

A new naphthoquinoneimine derivative from the marine algal-derived endophytic fungus Aspergillus niger EN-13

Cultivation of an endophytic fungus Aspergillus niger EN-13 that was isolated from the inner tissue of the marine brown alga Colpomenia sinuosa resulted in the characterization of a new naphthoquinoneimine derivative, namely, 5,7-dihydroxy-2-[1-（4- methoxy-6-oxo-6H-pyran-2-yl）-2-phenylethylamino]-[ 1,4]naphthoquinone. The structure of the new compound was established on the basis of various NMR spectroscopic analyses including 2D NMR techniques, El-MS, and HR-ESI-MS. This compound displayed moderate antifungal activity.

Effects of Chloroquine and Naphthoquinone on Prothrombin Time and Activated Partial Thromboplastin Time of Swiss Mice

Concerns on the coagulation variables, Prothrombin Time (PT) and Activated Partial Thromboplastin Time (APTT) which are part of coagulation parameters used in assessing haemostatsis in haematology, led to the study of the effects of naphthoquinone and chloroquine on the PT and APTT of mice infected with Plasmodium berghei, and treated with graded concentrations of chloroquine and naphthoquinone. Using brain thromboplastin with calcium and rabbit brain cephalosporin ad kaolin respectively the experiment aimed at demonstrating the effect of chloroquine with purity of 99.79% and naphthoquinone with purity of 97.00%, upon a three-day intraperitoneal administration at concentrations of 0.1 mg/kg, 0.5 mg/kg, 1.0 mg/kg and 2.0 mg/kg. Result showed that the APTT and PT of naphthoquinone at 2.0 mg/kg, were 196.67 seconds, and 67.63 seconds respectively, while the APTT and PT of chloroquine were 3.63 seconds and 1.40 seconds respectively for the same concentration. Also, naphthoquinone showed lower APTT but sustained PT at concentrations below 1.50 mg/kg whereas both APTT and PT increased from concentrations above 1.50 mg/kg. On the other hand chloroquine showed a lowered APTT between 0.00 to 0.15 mg/kg while PT was sustained, but both APTT and PT increased from concentration of 0.15 mg/kg gradually. This study conclusively showed that chloroquine has a shorter APTT and PT than naphthoquinones, even though they elicited similar actions. Apart from this, naphthoquinone and chloroquine belonging to the same family, naphthoquinone could be more toxic than chloroquine at the dosages equivalent to 1.50 mg/kg, therefore, any administration of naphthoquinone above this dosage should be closely monitored to avoid any form of danger to the patient.

One-Pot Process of Naphthoquinones Synthesis from Hydroquinone in the Presence of Solutions of Mo-V-P Heteropolyacids as Bifunctional Catalysts

1,4-Naphthoquinones (NQ) is a class of organic compounds with a number of important properties. However, the existing methods of their synthesis either give a low NQ yield or multistage and require a lot of time. In the present work new one-pot process of NQ synthesis from hydroquinone (HQ) and substituted 1,3-dienes at room temperature is proposed. The solution of heteropolyacid H7PMo8V4O40 (HPA-4) is used as a bifunctional (acid and redox) catalyst for this process. The influence of a number of factors on key process parameters has been studied. It is demonstrated that unsubstituted and a number of alkyl substituted NQ with the yields of 50% - 80% and purity of 92% - 99% can be obtained by this method. The results obtained allow to significantly simplify the synthesis of NQ directly from HQ in comparison with the described similar methods.

Pterocaryquinone, a Novel Naphthoquinone Derivative from Pterocarya tonkinesis

Pterocaryquinone, a novel 1,4-naphthoquinone derivative, was isolated from Pterocarya tonkinesis and its structure was elucidated by spectroscopic methods. Pterocaryquinone is a new dimeric 1,4-naphthoquinone derivative having a pentacyclic skeleton with two five-membered carbon rings, which provided a novel structural skeleton for 1,4-naphthoquinone derivatives and showed apoptosis-inducing activity toward mouse cancer tsFT210 cells.

A novel aza-naphthoquinone inhibits tumor growth by inducing apoptosis

Natural product menaquinone has been reported to exhibit antitumor activity mediated by inhibiting IDO-1 enzyme, and naphthoquinone compounds like pyranaphthoquinone have attracted extensive research interests since they share the naphthoquinone pharmacophores. In the present study, a novel series of aza-naphthoquinones was synthesized based on 6,7-dichloroquinoline-5,8-dione structure, and their cytotoxicities were screened using lung cancer cells. Among them CY-26-11 was identified as the most potent one. CY-26-11 concentration-dependently induced apoptosis in A549 human lung adenocarcinoma cells, as indicated by annexin-V staining. Further experimental data show that CY-26-11 down-regulated Bcl-2 while up-regulated Bax and Puma protein levels, and activated caspase-3. Finally, CY-26-11 significantly inhibited the growth of Lewis lung carcinoma xenografts in vivo without significant major toxicities. Taken together, our results demonstrate that CY-26-11 exhibited IDO-l-independent anti-tumor effects both in vitro and in vivo, providing a new anti-tumor mechanism for naphthoquinone compounds.

Synthesis,Crystal Structure of Ruthenium 1,2-Naphthoquinone-1-oxime Complex and Its Mediated C—C Coupling Reactions of Terminal Alkynes

Substituted decarbonylation reaction of ruthenium 1,2 naphthoquinone 1 oxime (1 nqo) complex, cis ,cis [Ru{ η 2 N(O)C 10 H 6O} 2(CO) 2] (1), with acetonitrile gave cis , cis [Ru{ η 2 N(O)C 10 H 6O} 2(CO)(NCMe)] (2). Complex 2 was fully characterized by 1H NMR, FAB MS, IR spectra and single crystal X ray analysis. Complex 2 maintains the coordination structure of 1 with the two naphthoquinonic oxygen atoms, as well as the two oximato nitrogen atoms located cis to each other, showing that there is no ligand rearrangement of the 1 nqo ligands during the substitution reaction. The carbonyl group originally trans to the naphthoquinonic oxygen in one 1 nqo ligand is left in its original position [O(5) Ru C(1), 174.0(6)°], while the other one originally trans to the oximato group of the other 1 nqo ligand is substituted by NCMe [N(1) Ru N(3), 170.6(6)° ]. This shows that the carbonyl trans to oximato group is more labile than the one trans to naphthoquinonic O atom towards substitution. This is probably due to the comparatively stronger π back bonding from ruthenium metal to the carbonyl group trans to naphthoquinonic O atom, than the one trans to oximato group, resulting in the comparatively weaker Ru—CO bond for the latter and consequently easier replacement of this carbonyl. Selected coupling of phenylacetylene mediated by 2 gave a single trans dimerization product 3, while 2 mediated coupling reaction of methyl propiolate produced three products: one trans dimerization product 4 and two cyclotrimeric products 5 and 6.

Cerium(Ⅳ)ammonium nitrate(CAN)-mediated regioselective synthesis and anticancer activity of 6-substituted 5,8-dimethoxy-1,4-naphthoquinone

6-Substituted 5,8-O-dimethyl-1,4-naphthoquinones（6-DMNQ）,the promising anticancer scaffolds,were selectively generated by oxidative demethylation of 2-substituted 1,4,5,8-tetramethoxynaphthalenes with CAN in EtOAc/H2O in comparatively high yields.An interesting finding was that apart from the reported electron-withdrawing effects of substituents on position 2 of naphthalene ring,regioselective synthesis of 6-DMNQ was largely dependent on the steric effects in CAN-mediated oxidation.The selective cytotoxicities of 6-DMNQ from the in vitro cell-based assays were exhibited between the cancer cells and normal cells.Moreover,most of sulfur-containing 6-DMNQ derivatives displayed better anticancer activities than the corresponding oxygen-containing ones,which could provide an available strategy for the design of 6-DMNQ derivatives as potential anticancer agents.

Two new glycosides from the genus of Cassia

Two new glycosides were isolated and characterized by spectral analysis from the seeds of Cassia obtusifolia and the leaves of Cassia angustifolia. The structure was elucidated as 1-hydroxyl-2-acetyl-3,8-dimethoxynaphthalene-6-O-β-D-apiofuranosyl- （1→2）-β-D-glucopyranoside and 2-acetyl-3-methyl-8-methoxyl-1,4-naphthoquinone-6-O-β-D-glucopyranoside.

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Studies on Chemical Constituents ofL. Erythrorhizon

ＳｔｕｄｉｅｓｏｎＣｈｅｍｉｃａｌＣｏｎｓｔｉｔｕｅｎｔｓｏｆＬ．ＥｒｙｔｈｒｏｒｈｉｚｏｎＢＡＩＧｕａｎｇａｎｄＪＩＮＸｉａｎｇ－ｊｕｎ（ＤｅｐａｒｔｍｅｎｔｏｆＣｈｅｍｉｓｔｒｙ，ＪｉｌｉｎＵｎｉｖｅｒｓｉｔｙ，Ｃｈａｎｇｃｈｕｎ．１３００２３）...

Synthesis and Antibacterial Activity of Juglone Derivatives

Nitro and halogen substituted derivatives of the juglone naphthoquinone were synthesized and assayed for their antibacterial activity. 8-Nitrojuglone was obtained as the exclusive product from the direct nitration of juglone with nickel （Ⅱ） nitrate and p-toluenesulphonic acid. In addition, a series of five 8-halojuglone derivatives were synthesized via a solvent-free Friedel-Crafts acylation reaction. One of the acylation reactions afforded an anthraquinone-type derivative as the minor product. The 8-nitrojuglone derivative displayed the most notable activity against S. aureus. However, all of the 8-halojuglone derivatives were found to be less active than juglone against the bacteria assayed.

Shikonin from Chinese herbal medicine induces GSDME-controlled pyroptosis in tumor cells

Objective:To investigate the potential anti-tumor mechanisms of naphthoquinone compound shikonin(SKN)extracted from the root of Chinese herbal medicine plant lithospermum(Lithospermum erythrorhizon Sieb.&Zucc.).Methods:We first observed that SKN treatment led to swelling and bubbles in HeLa cells that were similar to the phenotype of cell pyroptosis.Subsequently,the HeLa cells experienced a pyroptotic process with SKN,and this was then assessed using lactate dehydrogenase(LDH)release and propidium iodide(PI)/Hoechst double staining experiments.Pyroptosis is defined as gasdermin-mediated programmed necroptosis.To identify the potential pyroptosis machinery,two strategies were utilized that included a genome-wide clustered regularly interspaced short palindromic repeats(CRISPR)-associated protein 9 screening experiment and a pyroptosis reconstitution assay executed by each of the five known gasdermins(GSDMA-E).Moreover,endogenous cleavage was also detected in a panel of tumor cell lines.Results:Compared with the control,both the LDH release and PI/Hoechst double-staining experiments suggested that SKN induced perforation and enhancement of the permeability of the cell membranes that resulted in pyroptosis in HeLa cells(P=.028 and P=.032,respectively).In addition,the reconstitution assays in human embryonic kidney 293T(HEK-293T)cells and endogenous cleavage assays in HeLa cells indicated that the pyroptosis was controlled by GSDME.In addition,we also found SKN could trigger pyroptosis in a panel of tumor cell lines in which the cellular morphologies were proportional to the GSDME expression levels.Additionally,the cleavage of GSDME was also detected,and this was indicative of a similar GSDME-mediated mechanism.Conclusion:Our study not only explained the molecular mechanism of cytotoxicity of SKN to various tumor cells,but also provided additional information for the potential clinical application of natural naphthoquinone compounds against cancer.

Antifungal Activity of Crude Extracts of Tectona grandis L.f. against Wood DecayFungi

Wood is mainly made up of cellulose, hemicelluloses, lignin polymers and other organic and inorganic substances, making it susceptible to deteriorate by various biological agents. Tectona grandis L.f. (Teak) is a timberspecies with high resistance to biological deterioration, valued for its durability, beauty, and mechanical resistance.The purpose of this work was to evaluate the antifungal activity of crude extracts from teak on various fungi thatcause wood deterioration. For this, Teak heartwood was obtained, then fragmented and pulverized until obtaininga flour which was used for compounds extraction using the Soxhlet technique coupled to a rotary evaporatorthrough solvents of increasing polarity (hexane, dichloromethane, tetrahydrofuran, and acetone). The extractsobtained were tested against fungal organisms collected in the field, and the LC50 was determined using teak crudeextracts on Artemia salina as a biological model. The results obtained showed that a high flour yield was obtainedwith hexane (0.951 g), followed by tetrahydrofuran (0.446 g), dichloromethane (0.348 g), and acetone (0.152 g). Byusing nine fungal organisms that predominantly correspond to the genus Aspergillus, the extractable compoundswere tested, inhibiting 25% of mycelial growth with tetrahydrofuran (T. versicolor), and 40.9% with dichloromethane(G. trabeum). Likewise, the biological model of A. salina showed an LC50 of 84.9 μg/mL with hexane, 43.3 μg/mLwith dichloromethane, 59.6 μg/mL with tetrahydrofuran, and 54.7 μg/mL with acetone. For this reason, it is concluded that Teak wood contains many extractable compounds in relation to its weight, besides having antimicrobialactivity when extracted through polar compounds such as dichloromethane and tetrahydrofuran.

Effective assignment of positional isomers in dimeric shikonin and its analogs by ^(1)H NMR spectroscopy

An approach for distinguishing two types of positional isomers of dimeric shikonin and its analogs was explored with ^(4)JC,H long-range correlation by prolonging the acquisition time at ^(2,3)JC,H values of 2.0 and 8.0Hz.Furthermore,the ^(1)H(proton)nuclear magnetic resonance(NMR)pattern of phenolic hydroxyl protons was developed as a“diagnosis signal”to ascertain the relative location of each side chain in DMSO-d_(6) at sample concentrations of 0.022-0.034 mol/L.The chemical shift differences of 0.6ppm between OH-5' and OH-1 and between OH-8'and OH-4 are assigned to Type A and Type B,respectively.All reported ambiguous structures were corrected by this pattern.Additionally,the steric structures of isolated compounds were elucidated by quantum chemical calculations of electronic circular dichroism(ECD)spectra.

Identification and characterization of major constituents in Juglans mandshurica using ultra performance liquid chromatography coupled with time-of-flight mass spectrometry(UPLC-ESI-Q-TOF/MS)

The present study was designed to identify and characterize the major constituents in Juglans mandshurica Maxim. A simple, efficient and sensitive ultra performance liquid chromatography coupled with time-of-flight mass spectrometry(UPLC-ESIQ-TOF/MS) method was established and validated under positive and negative ion modes. The separation was performed on a Waters ACQUITY UPLC BEH C18 column(2.1 mm × 100 mm, 1.7 μm) by gradient elution with a mobile phase(Phase A: 0.1% aqueous formic acid solution, Phase B: 0.1% formic acid acetonitrile solution). A total of 165 compounds were rapidly selected by Targeted and Non-Targeted Peak Finding approaches, and then tentatively identified by comparing with reference substances or inferred through mass spectrometry fragment ion analysis and literature data. These compounds included 68 naphthalenequinones, 20 diarylheptanoids, 29 flavonoids, 20 triterpenes, and 28 phenolic acids. In conclusion, the present study provided an effective approach to identifying components in complex matrices of herbal medicines such as Juglans mandshurica Maxim.

Bioassay-guided isolation of novel and selective urease inhibitors from Diospyros lotus

Two new dimeric naphthoquinones, 5′,8′-dihydroxy-6,6′-dimethyl-7,3′-binaphthyl-1,4,1′,4′-tetraone(1; Di-naphthodiospyrol D) and 5′,8′-dihydroxy-5,8-dimethoxy-6,6′-dimethyl-7,3′-binaphthyl-1,4,1′,4′-tetraone(2; Di-naphthodiospyrol E), along with known naphthoquinones diospyrin(3) and 8-hydroxy diospyrin(4) were isolated from the chloroform fraction of extract of Diospyros lotus roots. Their structures were elucidated by advanced spectroscopic analyses, including HSQC, HMBC, NOESY, and J-resolved NMR experiments. The fractions and compounds 1-4 were evaluated for urease activity and phosphodiesterase-Ⅰ, carbonic anhydrase-Ⅱ and α-chymotrypsin enzyme inhibitory activities. Compounds 1 and 2 and their corresponding fractions showed significant and selective inhibitory effects on urease activities. The IC_(50) values of 1 and 2 were 260.4 ± 6.37 and 381.4 ± 4.80 μmol·L-1, respectively, using thiourea(IC_(50) = 21 ± 0.11 μmol·L^(-1)) as the standard inhibitor. This was the first report demonstrating that the naphthoquinones class showed urease inhibition.

Pharmacological and analytical aspects of alkannin/shikonin and their derivatives:An update from 2008 to 2022

Alkannin/shikonin(A/S)and their derivatives are naturally occurring naphthoquinones majorly found in Boraginaceae family plants.They are integral constituents of traditional Chinese medicine Zicao(roots of Lithospermum erythrorhizon).In last two decades significant increase in pharmacological investigations on alkannin/shikonin and their derivatives has been reported that resulted in discovery of their novel mechanisms in various diseases and disorders.This review throws light on recently conducted pharmacological investigations on alkannin/shikonin and their derivatives and their outputs.Various analytical aspects are also discussed and brief summary of patent applications on inventions containing alkannin/shikonin and its derivatives is also provided.

Efficient Synthesis of 3-Phenylnaphtho[2,3-b]furan-4,9-diones in Water and Their Fluorimetric Study in Solutions

A simple and efficient protocol has been developed for the synthesis of 3-phenylnaphtho[2,3-b]furan-4,9-diones by domino reaction of a-bromonitroalkenes to 2-hydroxynaphthalene-1,4-dione. With the optimal reaction condi- tions [NaOAc （120 mol%）, water, 70 ~C, 7 h], the scope of the domino reaction was explored and the green ap- proach provided the desired products in moderate to good yields at elevated temperature under aqueous-mediated conditions. A mechanistic rationalization for this reaction is also provided. The absorption characteristics of the compounds were examined by UV-Vis spectra and fluorescence spectroscopy. All compounds were fluorescent in solution emitting at blue light （432--433 nm）, green light （512--536 nm）, or yellow light （591 nm）.