[Show abstract][Hide abstract] ABSTRACT: Abstract Context: Plants of the Zephyranthes genus are globally used in folk medicine. In a previous study, Zephyranthes candida Linn. (Amaryllidaceae) was identified as having antiviral properties; this led to anti-poliovirus assay-guided isolation of compounds from crude methanol extract of the plant. Objective: Isolation of anti-poliovirus constituents from Z. candida. Material and methods: Active chloroform fraction from crude methanol extract of Z. candida (whole plant) was subjected to bioassay-guided fractionation; repeated column and preparative thin layer chromatography led to isolation of active compounds. Chemical structures were identified using spectroscopic techniques. Using serial two-fold dilution of maximum non-toxic concentration (MNTC) of each compound (0.0625-1 µg/mL for lycorine and 0.625-10 µg/mL for trisphaeridine and 7-hydroxy-3',4'-methylenedioxyflavan), the ability of extracts to inhibit viral-induced cell death in tissue culture was evaluated 72 h post-infection by the colorimetric method using MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide) dye. Regression analysis was used to determine 50% inhibitory concentration (IC50) and 50% cytotoxicity concentration (CC50), from which selective index (SI) was calculated. Results: From the chloroform fraction, three compounds were isolated and identified, namely lycorine (1), trisphaeridine (2), and 7-hydroxy-3',4'-methylenedioxyflavan (3) as the anti-polioviral components. Lycorine was the most active, with an IC50 value of 0.058 µg/mL followed by trisphaeridine (2) with an IC50 of 0.1427 µg/mL, and 7-hydroxy-3',4'-methylenedioxyflavan (3) with an IC50 of 0.2384 µg/mL. Discussions and conclusions: The antipoliovirus activity of trisphaeridine (2) and 7-hydroxy-3',4'-methylenedioxyflavan (3) is established in this report; these compounds are of moderate toxicity and have very good SI. They could be a potential template for the development of a new antiviral agent.
[Show abstract][Hide abstract] ABSTRACT: Acetone:chloroform (1:2) extract of the aerial parts of Euphorbia connata Boiss. (Euphorbiaceae) was investigated for its diterpenoids. This led to the isolation of one known and two new diterpenes, belonging to the pentahydroxy-13(17)-epoxy-8,10(18)-myrsinadiene and tetrahydroxy-5,6-epoxy-14-oxo-jatropha-11(E)-ene classes. The structures were elucidated based on (13)C and (1)H NMR as well as 2D NMR, IR and MS spectra and the cytotoxicity for compounds 1-3 were evaluated by using MTT assay against two human breast cancer cell lines. Myrsinane-type compounds - 3,7,14,15-tetraacetyl-5-propanoyl-13(17)-epoxy-8,10(18)-myrsinadiene (1) and 3,7,10,14,15-pentaacetyl-5-butanoyl-13,17-epoxy-8-myrsinene (2) - exhibited moderate inhibitory effects, with IC50 values of 24.53 ± 3.39 and 26.67 ± 1.41 μM against the MDA-MB cell line, and 37.73 ± 3.41 and 34.57 ± 2.12 μM against the MCF-7 cell line, respectively. Jatrophane-type diterpene - 5,6-epoxy-8,9,15-triacetyl-3-benzoyl-14-oxo-jatropha-11(E)-ene (3) - showed weak cytotoxicity, with IC50 values of 55.67 ± 7.09 μM against MDA-MB, and moderate cytotoxicity with IC50 values of 24.33 ± 3.21 μM against MCF-7 cell line.
[Show abstract][Hide abstract] ABSTRACT: isolation, structure elucidation and leishmanicidal activity of two new triterpenes, lantaninilic acid (I) and lantoic acid (II) along with six known triterpenes
[Show abstract][Hide abstract] ABSTRACT: Phytomedicine j o u r n a l h o m e p a g e : w w w . e l s e v i e r . d e / p h y m e d a b s t r a c t Biotransformation is an economically and ecologically viable technology which has been used extensively to modify the structures of many classes of biologically active products. The discovery of novel antimi-crobial metabolites from biotransformation is an important alternative to overcome the increasing levels of drug resistance by plant and human pathogens. Monoterpenes, the main constituents of essential oils, are known for their antimicrobial activities. In 2004, Farooq, Atta-Ur-Rahman and Choudhary published a review on fungal transformation of monoterpenes which covers papers published up to 2002. The present review not only updates the previous one but also discusses the antimicrobial activities (antibacterial, antifungal and antiviral) of biotransformed compounds.
[Show abstract][Hide abstract] ABSTRACT: Pyridyl-benzimidazole analogues 1–11 with variable substituent on phenyl ring of phenacyl moiety were synthesized and evaluated for their urease inhibitory activity. The compounds exhibited urease inhibition with IC50 between 19.22 and 77.31 µM. Compounds 4 (IC50 = 19.22 ± 0.49 µM) showed a urease inhibition comparable to thiourea (IC50 = 21.00 ± 0.01 µM) and twofold more active than acetohydroxamic acid (IC50 = 42.00 ± 1.26 µM) (standards), respectively. Moreover, compounds 5 (IC50 = 21.55 ± 0.36 µM), 1 (IC50 = 24.37 ± 0.41 µM), 7 (IC50 = 25.44 ± 0.19 µM), 6 (IC50 = 27.62 ± 0.25 µM), 3 (IC50 = 31.32 ± 0.75 µM), 8 (40.88 ± 0.36 µM) and 9 (41.22 ± 0.42 µM) also exhibited excellent activities when compared to the standards. Compounds 2 (IC50 = 65.46 ± 0.75 µM), 10 (68.99 ± 0.33 µM) and 11 (77.31 ± 0.51 µM) showed a moderate activity. The size of the substituents and their electron donating or withdrawing affects as well as their position on phenyl apparently modulates the enzyme inhibitory activity.
Medicinal Chemistry Research 10/2014; 23(10). · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Dehydroepiandrosterone (1) was incubated with a cell suspension culture of Codiaeum variegatum for biotransformational studies. After 10 days of incubation, four metabolites, 5α-androstane-3,17-dione (2), 5β-androstane-3,17-dione (3), androst-4-ene-3,17-dione (4), and 17β-hydroxyandrost-4-en-3-one (5), were obtained. The structures of these biotransformed products were elucidated by spectroscopic methods. Biotransformation using a cell suspension culture of Codiaeum variegatum provides an effective and convenient method to oxidize the 3β-hydroxy group in 1.
Chemistry of Natural Compounds 10/2014; 50(4):669-672. · 0.60 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Compounds 1–30 showed varying degree of α-glucosidase inhibition with IC50 values ranging between 187 and 420 μM. Compounds 1, 2, 3, 6, 8, 12, and 4 (IC50 = 187.7 ± 3.05, 203.4 ± 4.0, 240.7 ± 1.9, 252.9 ± 3.9, 285.2 ± 6.3, 399.07 ± 1.2, and 420.36 ± 5.6 μM, respectively) were found to be more active than standard acarbose (IC50 = 906 ± 6.3 μM). The synthetic compounds were also tested for urease inhibition. Compounds 5 (IC50 = 19.6 ± 1.0 μM) and 1 (IC50 = 21.6 ± 0.6 μM) showed better activity than standard drug thiourea (IC50 = 21.8 ± 1.6 μM). The crystal structures of compounds 15 and 16 are also reported.
Medicinal Chemistry Research 08/2014; · 1.61 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A series of 15 novel compounds incorporating the thieno[2,3-b]thiophene moiety were synthesized. The chemical structures of these compounds were deduced from elemental analyses, 1H-NMR, 13C-NMR, and ESI-mass spectral data. The enzyme inhibition potential of these compounds was evaluated, in vitro, against β-glucuronidase, xanthine oxidase, and -chymotripsin enzymes. The cytotoxicity was evaluated by a cell viability assay utilizing the tetrazolium dye 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). Among the compounds tested, compound 3 was the most potent β-glucuronidase inhibitor with an IC50 value of 0.9±0.0138 μM; it was much more active than the standard, D-saccharic acid 1-4- lactone (IC50 = 45.75±2.16 μM). Compound 12, on the other hand, was the most potent as a xanthine oxidase inhibitor with an IC50 of 14.4±1.2 μM. With the characterization of their mechanism of action and with further testing, these compounds could be useful candidates as anticancer drugs. In addition, the newly synthesized products were subjected to POM Analyses to get insights on the degree of their toxicity.
[Show abstract][Hide abstract] ABSTRACT: Dehydroabietic acid (DHA, 1), a natural occurring diterpene resin acid, is an abundant resin acid in conifers, representing a natural wood protectant. The aim of this study was to use microbial cell cultures as tools for modification of 1 in order to obtain value-added functional derivatives. A scaled-up biotransformation of 1 by filamentous fungus Cunninghamella elegans, Rhizopus stolonifer, Gibberella fujikuroi, and Cephalosporium aphidicola were conducted for the first time. Three hydroxylated metabolites; 1-hydroxydehydroabietic acid (2); 15-hydroxy dehydroabietic acid (3); and 16-hydroxy dehydroabietic acid (4). The structure of the hydroxylated metabolites were elucidated by 1-D (1H, 13C) and 2-D NMR (COSY, HMBC, HMQC, NOESY) techniques and MS analyses. Dehydroabietic acid (1) and their transformed products 2-4 exhibited a promising -Glucosidase inhibitory activity. Compound 1 showed 38 times more active than the standard alpha-Glucosidase inhibitor, deoxynojirimycin. Compound 1 and its transformed metabolites 2-4 also showed significant antibacterial activities.
Journal of Pharmacy and Pharmaceutical Sciences 08/2014; 6(7):375-378. · 2.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Oxadiazoles and thiadiazoles 1-37 were synthesized and evaluated for the first time for their α-glucosidase inhibitory activities. As a result, fifteen of them 1, 4, 5, 7, 8, 13, 17, 23, 25, 30, 32, 33, 35, 36 and 37 were identified as potent inhibitors of the enzyme. Kinetic studies of the most active compounds (oxadiazoles 1, 23 and 25, and thiadiazoles 35 and 37) were carried out to determine their mode of inhibition and dissociation constants Ki. The most potent compound of the oxadiazole series (compound 23) was found to be a non-competitive inhibitor (Ki=4.36±0.017μM), while most potent thiadiazole 35 was identified as a competitive inhibitor (Ki=6.0±0.059μM). The selectivity and toxicity of these compounds were also studied by evaluating their potential against other enzymes, such as carbonic anhydrase-II and phosphodiesterase-I. Cytotoxicity was evaluated against rat fibroblast 3T3 cell line. Interestingly, these compounds were found to be inactive against other enzymes, exhibiting their selectivity towards α-glucosidase. Inhibition of α-glucosidase is an effective strategy for controlling post-prandial hyperglycemia in diabetic patients. α-Glucosidase inhibitors can also be used as anti-obesity and anti-viral drugs. Our study identifies two novel series of potent α-glucosidase inhibitors for further investigation.
[Show abstract][Hide abstract] ABSTRACT: In a previous study, we evaluated the maternal and fetal safety of antimalarial herb Artemisia annua with artemisinin yield of 1.09%. Here, we attempted to ascertain the contraceptive claim of A. annua. Sexually matured female Wistar rats (180–220 g) were allotted into four study groups of six rats each. The control group received normal saline, while the A. annua-treated groups received 100, 200 and 300 mg/kg of A. annua for 2 weeks, followed by mating with proven fertile males (1:1). The rats were allowed to carry the pregnancy to term. At birth and weaning periods, selected reproductive outcome and fertility indices were determined. The results showed that A. annua significantly reduced litter size, reproductive outcome and fertility indices compared with the control ( p < 0.05). These results imply that A. annua could serve as a prospective contraceptive agent in addition to its antimalarial activity.
Natural Product Research 07/2014; · 1.03 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A variety of zwitterionic adducts were synthesized by using means green chemistry method. The products contain the biologically active barbituric acid moiety embedded in zwitterion products. Both features are pharmaceutically relevant. The chemical structures were deduced by 1H-, 13C-, NMR and HRMS spectral analysis, and X-Ray diffraction techniques. In vitro evaluation for the antioxidant activities were carried out towards the inhibition of nitric oxide (NO) radical, known to regulate a mechanism of signals for various cellular functions. NO also play an important role as a mediator of various pathological conditions responsible for cellular damages such as strokes, cancers, diabetes, chronic heart failure and inflammatory disease and various neurodegenerative disorders. All tested compounds were found to be more potent nitric oxide scavengers as compared to standard drug ascorbic acid (IC50 = 618±2.0 µM). Compounds 4c and e exhibiting several hundred fold more activity against nitric oxide radical with IC50 values of 69±1.66 and 70.1±0.89 µM respectively, as compared to standard drug ascorbic acid (IC50 = 618±2.0 µM).
European Journal of Medicinal Chemistry 07/2014; 84:146-154. · 3.43 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: AimsThe emergence of multi-drug resistant (MDR) Staphylococcus aureus is a challenge for the treatment of infections. We report here the antimicrobial potential of artonin I against MDR S. aureus, its mechanism of reversal of resistance and synergistic effects by combinational therapy.Methods and ResultsArtonin I, a flavonoid obtained from Morus mesozygia Stapf., inhibited the bacterial efflux pump and induced depolarization of the cell membrane. To study the dose-dependent production of reactive oxygen species in MDR cells by artonin I, lucigenin chemiluminescence assay was employed. Reversal of multi-drug resistance by artonin I, in combination with antibiotics, was measured by a fractional inhibitory concentration index assay. The effect of artonin I on ultra-structural features was studied by microscopy. Artonin I increased the penetration of ethidium bromide by blocking the efflux mechanism. It also helped anionic probe DiBAC4(3) to bind with the lipid rich cellular components by causing depolarization of the cell membrane. Artonin I reversed multi-drug resistance and increased the susceptibility of existing antibiotics by lowering their minimum inhibitory concentrations (MICs).Conclusions
Artonin I was identified both as a new antibacterial agent and as a helper molecule to potentiate the action of otherwise inactive antibiotics.This article is protected by copyright. All rights reserved.
Journal of Applied Microbiology 07/2014; · 2.20 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Phytochemical investigation of the whole plant of Marrubium vulgare L., led to the isolation of three new secondary metabolites, 11-oxomarrubiin (1), vulgarcoside A (2) and 3-hydroxyapigenin-4'-O-(6"-O-p-coumaroyl)-beta-D-glucopyranoside (3), along with four known constituents 4-7 from the polar fractions of the methanolic extract. The structures of all compounds were deduced on the basis of NMR data and HRESI-MS measurements. The new constituents 1-3 exhibited moderate to low level of inhibition on nitric oxide (NO.) production. The compound 2 also showed a moderate inhibition on pro-inflammatory cytokine TNF-alpha. The new constituents 1-3 showed no inhibitory effect on Reactive Oxygen Species (ROS) production.
[Show abstract][Hide abstract] ABSTRACT: C16H18N2O3, triclinic, P1 (no. 2), a = 8.7144(8) Å, b = 9.2142(9) Å, c = 9.6953(9) Å, a = 78.859(2)°,
b = 74.822(2)°, g = 89.031(2)°, V = 736.7 Å3, Z = 2, Rgt(F) = 0.0588, wRref(F2) = 0.1867, T = 273 K.
Zeitschrift für Kristallographie 06/2014; 229. · 1.24 Impact Factor