Spectroscopy - Volume 23, issue 1

Authors: Yang, Jianhong | Wang, Ruilin | Cao, Yi | Fei, Yurong | Huang, Yuying | He, Wei | Liu, Jing

Article Type: Research Article

Abstract: To evaluate the anti-osteoporotic effect of antler blood, the relationship between the change of element content and the bone mineral density (BMD) increase in femur was investigated. Female Wistar rats were randomly divided into three groups: sham-operated group (SHAM, n=5), ovariectomized group (OVX, n=5) and ovariectomized group with antler blood treatment (n=5). The femoral BMD was analyzed by dual-energy X-ray absorptiometry (DXA) and the element relative content was determined by synchrotron radiation X-ray fluorescence (SRXRF) microprobe. The results showed that the femoral BMD in ovariectomized rats was significantly lower than that of sham-operated rats (p<0.05) but reversed by antler blood …treatment (p<0.05). A further study demonstrated that the relative contents of phosphorus (P), calcium (Ca), zinc (Zn) and strontium (Sr) were obviously lower in ovariectomized rats compared to sham-operated rats but only the relative contents of P, Ca and Zn were normalized by antler blood treatment (p<0.05). Our experiments revealed that loss of element Ca, P, Zn and Sr was closely related to the BMD reduction in ovariectomized rats and the anti-osteoporotic effect of antler blood was mediated by increasing the contents of P, Ca and Zn. Show more

Keywords: Element analysis, BMD, osteoporosis, femur, SRXRF

DOI: 10.3233/SPE-2009-0372

Citation: Spectroscopy, vol. 23, no. 1, pp. 1-9, 2009

Authors: Nardo, Luca | Bondani, Maria | Andreoni, Alessandra

Article Type: Research Article

Abstract: We perform time-correlated single-photon counting measurements with 30-ps resolution of the fluorescence emitted by the donor fluorophores of donor–acceptor pairs covalently labeling DNA synthetic oligonucleotides by using a non-commercial single-photon avalanche diode. The measurements allow us to precisely assess the fluorescence resonant energy transfer efficiency of the pairs in solutions containing the oligonucleotides and DNA–ligands, for different ratios of the DNA base-pair to ligand concentrations. A quantitative evaluation of the deformations of DNA double strands following the ligand binding is obtained, as the transfer efficiency is a steep function of the donor-to-acceptor distance. The results lead to an easy and …cheap method to discriminate between the binding modes of minor groove and base intercalating ligands. Show more

Keywords: Binding-induced conformational transition, DNA base intercalator, DNA minor groove-binder, time-correlated single-photon counting, fluorescence resonance energy transfer

DOI: 10.3233/SPE-2009-0370

Citation: Spectroscopy, vol. 23, no. 1, pp. 11-28, 2009

Authors: Kanakis, C.D. | Nafisi, Sh. | Rajabi, Mehdi | Shadaloi, Azadeh | Tarantilis, P.A. | Polissiou, M.G. | Bariyanga, J. | Tajmir-Riahi, H.A.

Article Type: Review Article

Abstract: Flavonoids are natural polyphynolic compounds with major antioxidant activity that can prevent DNA damage. The anticancer and antiviral activities of these natural products are attributed to their potential biomedical applications. In this review we are examining how the antioxidant flavonoids bind DNA and RNA and what mechanism of action is involved in preventing DNA damage. Detailed spectroscopic data on the interactions of morin (mor), apigenin (api), naringin (nar), quercetin (que), kaempferol (kae) and delphinidin (del) with DNA and transfer RNA in aqueous solution at physiological conditions were analysed. The structural analysis showed flavonoids mainly intercalate into DNA and RNA duplexes …with minor external binding to the major or minor groove and the backbone phosphate group with overall binding constants for DNA adducts Kmor =5.99×103 M−1 , Kapi =7.10×104 M−1 , and Knar =3.10×103 M−1 , Kque =7.25×104 M−1 , Kkae =3.60×104 M−1 and Kdel =1.66×104 M−1 , and for tRNA adducts Kmor =9.15×103 M−1 , Kapi =4.96×104 M−1 , and Knar =1.14×104 M−1 , Kque =4.80×104 M−1 , Kkae =4.65×104 M−1 and Kdel =9.47×104 M−1 . The stability of adduct formation is in the order of que > api > kae > del > mor > nar for DNA and del > api > que > kae > nar > mor for tRNA. Low flavonoid concentration induces helical stabilization, whereas high pigment content causes helix opening. Flavonoids induce a partial B to A–DNA transition at high pigment concentration, while tRNA remains in A-family structure upon flavonoid complexation. The antioxidant activity of flavonoids changes in the order delphinidin > quercetin > kaempferol > morin > naringin > apigenin. The results show intercalated flavonoid molecule can act as an antioxidant and prevent DNA damage. Show more

Keywords: DNA, tRNA, antioxidant, flavonoids, binding sites, binding constant, conformation, FTIR, UV-visible spectroscopy

DOI: 10.3233/SPE-2009-0368

Citation: Spectroscopy, vol. 23, no. 1, pp. 29-43, 2009

Authors: Rabbani, Ghulam | Isab, Anvarhusein A. | Al-Arfaj, Abdul Rahman | Ahmad, Saeed | Saleem, Muhammad | Hameed, Abdul | Akbar, Erum

Article Type: Research Article

Abstract: Mercury(II) complexes of thiolates having the general formula [Hg(RS)Cl2 ]− and [Hg(RS)2 ] have been prepared and characterized by IR and NMR (1 H and 13 C) spectroscopy (RSH = 2-aminoethanethiol hydrochloride (Aet), cysteine (Cys), thiosalicylic acid (Ts) and 2-mercaptonicotinic acid (Mnt)). The spectral data suggests that the coordination of thiolates to mercury(II) occurs through the sulfur as indicated by the absence of S–H vibrations in IR and significant downfield shifts in the C–S resonance in 13 C NMR. However, in Mnt complexes, coordination through both sulfur and nitrogen is indicated. Antimicrobial activities of the complexes were evaluated by …minimum inhibitory concentration and the results showed that the complexes exhibited a wide range of activities against gram-negative bacteria (E. coli, P. aeruginosa), while moderate activity was observed against a mold, P. citrinum. Show more

Keywords: Mercury(II), thiolates, NMR spectroscopy, antimicrobial activity

DOI: 10.3233/SPE-2009-0369

Citation: Spectroscopy, vol. 23, no. 1, pp. 45-50, 2009

Authors: Bratu, I. | Kacso, Irina | Borodi, Gh. | Constantinescu, Daniela E. | Dragan, Felicia

Article Type: Research Article

Abstract: Solid state interactions of bioactive substance (4-cyclohexyl-1-[2-[(2-methyl-1-propanoyloxy-propoxy)-(4-phenylbutyl)phosphoryl]acetyl]-pyrrolidine-2-carboxylic acid, called Fosinopril), with β-cyclodextrin (β-CD), the so-called inclusion compounds of a bioactive (cardiovascular) drug is obtained by different preparation methods: kneading, co-precipitation and freeze-drying. The so obtained compounds were investigated by FTIR spectroscopy, X-ray diffraction method, and differential scanning calorimetric measurements (DSC) to evidence their formation. X-ray diffraction patterns show that the inclusion compound was obtained for kneaded, co-precipitation and freeze-dried products. The crystalline/amorphous degree for these compounds was also investigated. Molecular modeling (MM+ molecular mechanics) shows the spatial architecture of the inclusion compound in good agreement with FTIR experimental data: the …drug is included with the propanoyloxy-propoxy group inside β-cyclodextrin cavity. These findings may constitute a direct contribution to the molecular encapsulation of Fosinopril into β-cyclodextrin, improving Fosinopril stability and bioavailability of the drug, also. Show more

Keywords: FTIR, X-ray powder diffraction, DSC, molecular modeling, inclusion compounds, β-cyclodextrin

DOI: 10.3233/SPE-2009-0373

Citation: Spectroscopy, vol. 23, no. 1, pp. 51-58, 2009