Phenolics content and antioxidant activity of tartary buckwheat from different locations

Two tartary buckwheat samples (Xingku No.2 and Diqing) grown at three locations were analyzed for free and bound phenolic content and antioxidant properties. Moreover, the relative contributions of variety and growing environment to phenolic content and antioxidant properties were determined, as well as correlations of these properties to growing conditions. The total phenolic contents varied from 5,150 to 9,660 μmol of gallic acid equivalents per 100 gram of dry weight (DW) of tartary buckwheat and the free phenolics accounted for 94% to 99%. Rutin content was in the range from 518.54 to 1,447.87 mg per 100 gram of DW of tartary buckwheat. p-Hydroxybenzoic, ferulic and protocatechuic acids were the prominent phenolic acids and other phenolics, including p-coumaric, gallic, caffeic, vanillic and syringic acids were also detected. Tartary buckwheat exhibited higher DPPH· and ABTS·+ scavenging activities and was more effective at preventing the bleaching of β-carotene in comparison with reference antioxidant and plant phenolics constituents. Additionally, growing conditions and the interaction between variety and environment may have more contribution than variety to individual phenolics and antioxidant properties of tartary buckwheat. Environmental parameters such as higher altitudes may also have an increasing effect on rutin and phenolic acids. This study suggests that tartary buckwheat has potential health benefits because of its high phenolic content and antioxidant properties. These components could also be enhanced by optimizing the growing conditions of a selected variety.     

Alpha-glucosidase inhibitors from Millettia conraui

A new geranylated isoflavone, 7-O-geranyl-6-methoxypseudobaptigenin (1) was isolated from the stem barks of Millettia conraui, along with known compounds 5-methoxydurmillone (2), conrauinone A (3), beta-amyrine (4), sitosterol (5), 3-O-beta-D-glucopyranosyl sitosterol (6) and n-docosanol (7). Compounds 1 and 4 showed a significant alpha-glucosidase inhibitory activity. The structures of the compounds were determined by analysis of their spectroscopic data.     

N-monocarbamoyl derivatives of symmetrical diamines with antiviral activity

Some new N-monocarbamoyl symmetrical diamines have been prepared by the addition of symmetrical amines to isocyanates or isothiocyanates. 2,6-Diaminopyridine (1), (1R,2R)-1,2-diaminocyclohexane [(1R,2R)-2], meso-1,2-diaminocyclohexane (meso-2), or (1R,2R)-1,2-diphenylethylenediamine (3) were used as the starting symmetrical diamine frameworks. All of the newly synthesized compounds were subjected to an evaluation of antiviral activity with herpes simplex virus (HSV)-1. N-Monocarbamoyl 2,6-diaminopyridines (5a, b) showed significant antiviral activity (EC(50)=17.0, 6.2 microg/ml) comparable to that of N-monododecanoyl 2,6-diaminopyridine (A2). As a result, compound 5a showed a better selectivity index (CC(50)/EC(50) = ca. 10.0) than that of A2.     

Isoflavones and rotenoids from the leaves of Millettia brandisiana

A new isoflavone, 4'-gamma,gamma-dimethylallyloxy-5,7,2',5'-tetramethoxyisoflavone, brandisianin A (1), was isolated from the leaves of Millettia brandisiana, along with one synthetically known isoflavone, 7,4'-di-O-prenylgenistein (2) and twelve known compounds. The structures were elucidated on the basis of extensive spectroscopic analysis. Two isolated compounds were tested for anti-inflammatory activity; 12a-hydroxy-alpha-toxicarol (11) showed significant anti-inflammatory activity.     

A new isoflavone with anti-inflammatory effect from the seeds of Millettia pachycarpa

Abstract

A new isoflavone, milletenol A (1), along with four known flavonoids (2–5) were isolated from the seeds of Millettia pachycarpa. The structure of 1 was established by extensive spectroscopic methods while known compounds were identified by comparisons with literature data. Compound 1 and 2 showed significant anti-inflammatory activities against nitric oxide production in LPS-induced RAW264.7 macrophages. The state of CuSO₄-stimulated inflammation was effectively alleviated by compound 1 in zebrafish. However, no significant cytotoxicity against human breast cancer cells was observed among all isolates.     

Electroanalytical study of guanine synthetic derivatives with antiviral activity

Experimental information on the electrochemical behavior of guanine synthetic derivatives (acyclovir, valacyclovir, ganciclovir, and famciclovir) with the strong antiviral activity on presynthesized activated carbosital electrode (CSE) in aqueous solutions of different acidity is obtained. The mechanism of irreversible oxidation of substances containing guanidine group (–NH–C(NH–)=N–) is discussed and the dependences of current and potential of experimental anodic peaks on the potential scan rate, the nature and acidity of supporting electrolyte solution, and also on the concentration of depolarizer and the time of its accumulation on the electrode surface are found. It is shown that all other factors being equal (0.1 М phosphate buffer, рН 6), the position of the observed anodic peak depends substantially on the nature of acyclic substituent at N(9) of imidazole ring in the aminopurine molecule: the susceptibility to oxidation decreases in the series Gua (E_pa = 0.84 V), ACV (E_pa = 1.00 V), VACV (E_pa = 1.04 V), GCV (E_pa = 1.07 V), FCV (E_pa = 1.20 V). It is shown that the electrocatalytic activity and the high absorbability of the activated CSE with respect to substances tested make it possible to reach their lower detection limits (20–40 nM) in multicomponent solutions.     

N-long-chain monoacylated derivatives of 2,6-diaminopyridine with antiviral activity

N-Monoacyl-2,6-diaminopyridines (2a-c) and N,N'-diacyl-2,6-diaminopyridines (3a-c) were synthesized from 2,6-diaminopyridine by acylation with the corresponding acyl halide or by dehydration with the corresponding carboxylic acid using 1,3-dicyclohexylcarbodiimide (DCC). The antiviral activities of N-monoacyl- and N,N'-diacyl-2,6-diaminopyridines (2a-c and 3a-c) were estimated using plaque reduction assay with HSV-1. All N-monoacyl derivatives (2a-c) showed significant anti-herpes simplex virus (HSV)-1 activity (EC(50) = 15.3-18.5 microg/ml). The CC(50) values of 2a-c measured using Vero cells ranged at 37.5-50.0 microg/ml. These compounds showed no significant antibacterial activities with Escherichia coli or Staphylococcus aureus even at a concentration of 1 mg/ml. The N,N'-diacyl derivatives (3a-c) showed no significant anti-HSV-1 activity.     

Bitriazolyl acyclonucleosides with antiviral activity against tobacco mosaic virus

Bitriazolyl acyclonucleosides were synthesized via the Huisgen reaction and then subjected to ammonolysis. The antiviral activity of these nucleosides against tobacco mosaic virus (TMV) was assessed. Like the previously described bitriazolyl compounds, these new bitriazolyl acyclonucleosides were found to show anti-TMV activity. This suggests that the bitriazolyl moieties are important structural features involved in the antiviral activity of these compounds.     

Pharmacological evaluation of benzimidazole derivatives with potential antiviral and antitumor activity

In recent years the synthesis of benzimidazole and its derivatives has attracted the attention of many organic chemists because of the compounds’ interesting biological activity and the crucial importance of the benzimidazole unit in the function of these biologically important molecules. Benzimidazole-based polyheterocyclic compounds have several interesting biological properties. Simple synthetic strategies leading to benzimidazole-based fused polyheterocyclic systems and the antiviral and anticancer biological activity of the compounds are surveyed in this review article.     

Synthesis and antiviral activity of nonannulated tetrazolylpyrimidines

Chemistry of Heterocyclic Compounds - Nonannulated tetrazolylpyrimidines in the structure of which the heterocyclic fragments are separated by hydrazinocarbonylmethyl, methylpyrazolyl groups or a...     

Stilbene derivatives with antifungal and radical scavenging properties from the stem bark of Artocarpus nobilis

Antifungal activity-guided fractionation of the n-butanol extract from the methanol extract of the stem bark of Artocarpus nobilis furnished two stilbene derivatives (E)-4-isopentenyl-3,5,2',4'-tetrahydroxystilbene and (E)-4-(3-methyl-E-but-1-enyl)-3,5,2',4'-tetrahydroxystilbene. Both compounds showed strong antifungal activity against Cladosporium cladosporioides and high radical scavenging activity towards the DPPH radical in TLC bio-autography method.     

Self-assembling peptide nanotubes with antiviral activity against hepatitis C virus

Hepatitis C virus (HCV) infects chronically 3% of the world population and the current therapy against this pathogen is only partially effective. With the aim of developing novel antiviral strategies against HCV, we screened a D,L-α-peptide library using an?unbiased methodology based on a cell culture infection system for HCV. We found a family of highly?active amphiphilic eight-residue cyclic D,L-α-peptides that specifically blocked entry of all tested HCV genotypes into target cells at a postbinding step without affecting infection by other enveloped RNA viruses. Structure-activity relationship studies indicate that antiviral activity was dependent on cyclic D,L-α-peptide self-assembly processes and that, although they possess a net neutral charge,?they display a characteristic charge distribution. Our results indicate that supramolecular amphiphilic peptide structures constitute a class of highly selective HCV entry inhibitors.     

Modular alpha-helical mimetics with antiviral activity against respiratory syncitial virus

A 13-residue peptide sequence from a respiratory syncitial virus fusion protein was constrained in an alpha-helical conformation by fusing two back-to-back cyclic alpha-turn mimetics. The resulting peptide, Ac-(3-->7; 8-->12)-bicyclo-FP[KDEFD][KSIRD]V-NH(2), was highly alpha-helical in water by CD and NMR spectroscopy, correctly positioning crucial binding residues (F488, I491, V493) on one face of the helix and side chain-side chain linkers on a noninteracting face of the helix. This compound displayed potent activity in both a recombinant fusion assay and an RSV antiviral assay (IC(50) = 36 nM) and demonstrates for the first time that back-to-back modular alpha-helix mimetics can produce functional antagonists of important protein-protein interactions.     

Three New Isoprenylated Flavones from Artocarpus chama Stem and Their Bioactivities

Phytochemical investigation of Artocarpus chama stem was performed by chromatographic techniques, resulting from the isolation and structure elucidation of three new compounds, namely 3′-farnesyl-apigenin (1), 3-(hydroxyprenyl) isoetin (2), and 3-prenyl-5,7,2′,5′-tetrahydroxy-4′-methoxyflavone (3), and five known compounds, namely homoeriodictyol (4), isocycloartobilo-xanthone (5), artocarpanone (6), naringenin (7), and artocarpin (8). From the screening result, A. chama extract showed a potent tyrosinase inhibitory effect. Ihe isolated compounds 1, 4 and 6 also exhibited tyrosinase inhibition with IC₅₀ of 135.70, 52.18, and 38.78 µg/mL, respectively. Moreover, compounds 3, 4, 5, 6, and 8 showed strong activity against Staphylococcus epidermidis, S. aureus, methicillin-resistant S. aureus, and Cutibacterium acnes. This study is the first report on phytochemical investigation with new compounds and biological activities of A. chama. Skin infection can cause dark spots or hyperpigmentation. The isolated compounds that showed both anityrosinase and antimicrobial activities will be further studied in in vivo and clinical trials in order to develop treatment for hyperpigmentation, which is caused by infectious diseases by microorganisms.     

Cytotoxic arylbenzofuran and stilbene derivatives from the twigs of Artocarpus heterophyllus

Four new natural products, including three arylbenzofurans named heterophyllenes A-C (1–3), and one stilbene named heterophyllene D (4), together with twenty-one known compounds were isolated from the twigs of Artocarpus heterophyllus and their structures elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopy. The cytotoxic activity of selected compounds against KB, MCF-7 and NCI-H187 cell lines was evaluated. Heterophyllene C (3) exhibited cytotoxicity against the MCF-7 cell line with an IC₅₀ value of 12.56 μM. Additionally, the known compounds norartocarpin and artocarpin showed cytotoxic activity against MCF-7 and KB cell lines with IC₅₀ values of 10.04 and 13.57 μM, respectively. Both compounds also displayed cytotoxicity against the NCI-H187 cell line with values of 14.78 and 14.21 μM, respectively.     

Synthesis and antiviral activity of scopadulcic acids analogues

The synthesis and antiviral properties of several scopadulcic acid analogues functionalized at C-6/C-7 and C-13 is reported. The preparation of advanced intermediates for the synthesis of scopadulcic acid B/scopadulciol analogues is also described. The biological study revealed the importance of polar groups at C-13, while the stereochemistry at C-8 was not critical for activity.