Study on chemical constituents from green husk of Juglans sigillata / 中草药

Objective: To investigate the chemical constituents in the green husk of Juglans sigillate. Methods: The chemical constituents were isolated by silica gel, RP-18, MCI column chromatographies and so on. The structures were identified on the basis of spectroscopic analysis (MS, 13C-NMR, 1H-NMR). Results: Eleven compounds were isolated from the extract of green husk of J. sigillate. And their structures were characterized as: sinapaldehyde (1), (Z)-10-eicosenoic acid (2), 5α, 8α-epidioxyergosta-6, 22E-diene-3β-ol (3), 5, 8-dihydroxy-4-methoxy-α-tetralone (4), regiolone (5), 4, 5-dihydroxy-α-tetralone (6), 4, 5, 8-trihydroxy-α-tetralone (7), 5-hydroxy-4-methoxy-α-tetralone (8), 5-hydroxy-2-methoxy-1, 4-naphthoquinone (9), naringenin (10), and β-sitosterol (11). Conclusion: Compounds 1-2 are isolated from the plants of Juglans Linn. for the first time.

2-Bromo-1,4-naphthoquinone: a potentially improved substitute of menadione in Apatone™ therapy

Apatone™, a combination of menadione (2-methyl-1,4-naphthoquinone, VK3) and ascorbic acid (vitamin C, VC) is a new strategy for cancer treatment. Part of its effect on tumor cells is related to the cellular pro-oxidative imbalance provoked by the generation of hydrogen peroxide (H2O2) through naphthoquinone redox cycling. In this study, we attempted to find new naphthoquinone derivatives that would increase the efficiency of H2O2 production, thereby potentially increasing its efficacy for cancer treatment. The presence of an electron-withdrawing group in the naphthoquinone moiety had a direct effect on the efficiency of H2O2 production. The compound 2-bromo-1,4-naphthoquinone (BrQ), in which the bromine atom substituted the methyl group in VK3, was approximately 10- and 19-fold more efficient than VK3 in terms of oxygen consumption and H2O2 production, respectively. The ratio [H2O2]produced / [naphthoquinone]consumed was 68 ± 11 and 5.8 ± 0.2 (µM/µM) for BrQ and VK3, respectively, indicating a higher efficacy of BrQ as a catalyst for the autoxidation of ascorbic acid. Both VK3 and BrQ reacted with glutathione (GSH), but BrQ was the more effective substrate. Part of GSH was incorporated into the naphthoquinone, producing a nucleophilic substitution product (Q-SG). The depletion of BrQ by GSH did not prevent its redox capacity since Q-SG was also able to catalyze the production of reactive oxygen species. VK3/VC has already been submitted to clinical trials for the treatment of prostate cancer and has demonstrated promising results. However, replacement of VK3 with BrQ will open new lines of investigation regarding this approach to cancer treatment.

Larvicidal activity of extracts from three Plumbago spp against Anopheles gambiae

Three Plumbago spp have been tested for mosquito larvicidal activity. The crude extracts exhibiting the highest larvicidal activity against Anopheles gambiae were hexane (LC50 = 6.4 μg/mL) and chloroform (LC50 = 6.7 μg/mL) extracts from Plumbago zeylanica Linn, chloroform (LC50 = 6.7 ug/mL) extract from Plumbago stenophylla Bull and ethyl acetate (LC50 = 4.1 μg/mL) extract from Plumbago dawei Rolfe. These LC50 values were within 95 percent confidence limits. 5-hydroxy-2-methyl-1,4-naphthoquinone (plumbagin) 1 (LC50 = 1.9 μg/mL) and β-sitosterol 2 were characterised from ethyl acetate extract of root bark of P. dawei, a native medicinal plant growing in Kenya, based on spectral analysis and comparisons with data in literature.

Molluscicidal activity of 2-hydroxy-[1, 4]naphthoquinone and derivatives

The toxic profile of lawsone (2-hydroxy-[1,4]naphthoquinone) and a series of [1,4]naphthoquinone derivatives was evaluated against the brine shrimp Artemia salina and against the mollusk Biomphalaria glabrata, the main transmitting vector of schistosomiasis in Brazil. Of the seventeen compounds tested nine fell below the threshold of 100 µg/mL set for potential molluscicidal activity by the World Health Organization. As a general rule derivatives with non-polar substituents presented the highest molluscicidal activities. These substances showed significant toxicity in A. salina lethality bioassay.

A toxicidade da lausona (2-hidroxi-1,4)-naftoquinona e de diversos derivados foi avaliada frente à Artemia salina e ao molusco Biomphalaria glabrata, o principal vetor de transmissão da esquistossomose no Brasil. Entre os dezessete compostos testados, nove apresentaram um perfil de toxicidade menor que 100 µg/mL, sendo potenciais agentes moluscicidas de acordo com as designações da Organização Mundial da Saúde. No presente estudo, os compostos contendo substituintes apolares exibiram as maiores atividades. Estes compostos também se mostraram significantemente tóxicos frente à A. salina.

Chemical constituents from exocarp of Juglans mandshurica / 中草药

Objective To study the chemical constituents from the exocarp of Juglans mandshurica.Methods The compounds were isolated by Diaion HP-20,Sephadex LH-20,MCI CHP-20,and silica gel column chromatography.Their structures were identified by physicochemical properties and spectroscopic analysis.Results Twelve compounds were elucidated as pinostrobin (Ⅰ),quercetin (Ⅱ),quercetin-3-O-?-D-glucoside (Ⅲ),chrysophanol (Ⅳ),gallic acid (Ⅴ),4-hydroxyl-cinnamic acid methyl ester (Ⅵ),vanillin (Ⅶ),caffeic acid (Ⅷ),4-hydroxylcinnamic acid (Ⅸ),?-sitosterol (Ⅹ),daucosterol (Ⅺ),and 5-hydroxyl-1,4-naphthoquinone (ⅩⅡ).Conclusion The compounds Ⅰ,Ⅳ,and Ⅵ—Ⅸ are isolated from J.mandshurica for the first time.

Chemical constituents in root and rhizome of Polygonum cuspidatum / 中草药

Objective To study the chemical constitients of Polygonum cuspidatum.Methods The compounds were isolated through column chromatography and their structures were elucidated through physicochemical and spectral analyses.Results Seven compounds were obtained from the diethyl ether fraction of ethanol extract and identified as physcion(Ⅰ),emodin(Ⅱ),ambrettolide(Ⅲ),?-sitosterol(Ⅳ),oleanolic acid(Ⅴ),coumarin(Ⅵ),and 2-ethoxy-8-acetyl-1,4-naphthoquinone(Ⅶ).Conclusion Compound Ⅶ is a new compound named as cuspidatumin A,and compound Ⅲ is obtained from P.cuspidatum for the first time.