Host-guest interaction of 3-hydroxyflavone and 7-hydroxyflavone with cucurbit [7]uril: A spectroscopic and calorimetric approach.

The modulation of photophysical behaviour of small organic molecules in the presence of macrocycles is one of the most interesting areas of research. In this work we reported the interaction of two biologically active molecules 3-hydroxyflavone and 7-hydroxyflavone with macrocyclic host cucurbit [7]uril in aqueous medium. To investigate the change of photophysical properties of these two flavones, we have used steady state absorption, fluorescence, time resolved fluorescence emission spectroscopy and isothermal titration calorimetric technique. It is observed that on complexation with cucurbit [7]uril, the excited state proton transfer processes in both flavones have been facilitated. Isothermal titration calorimetric method was used in order to investigate the involvement of thermodynamic parameters in complexation between flavone with cucurbit [7]uril. The changes in thermodynamic properties due to the complexation of the flavones molecules with cucurbit [7]urils help to understand about the governing parameters involved in this complexation. The inclusion of flavone molecules inside the cavity of cucurbit [7]uril molecules was studied theoretically to decipher the molecular orientation of flavones in the presence of cucurbit [7]uril. The structure of HOMO and LUMO of the complexes between cucurbit [7]uril with flavones was reported. This study will be helpful to get the knowledge about the modulation of photophysical properties of the flavones molecules on addition of macrocyclic host cucurbit [7]uril. This study will be helpful for the use of cucurbit [7]uril as a potential drug delivery system.

Interaction of Biologically Active Flavins inside Bile Salt Aggregates: Molecular Level Investigation.

In this work we have studied the photophysics of biologically active flavin molecule lumichrome (LCM) in different bile-salt aggregates. With alteration of the functional groups of the bile salts, the photophysics of confined fluorophore is largely affected and shows difference in their spectral behavior. This study also reveals the selective prototropic species of LCM present in bile salt aggregates. In the presence of the bile salt aggregates, LCM molecule shows excitation and emission wavelength-dependent emission properties, indicating switch over of the structural change of different prototropic form of the LCM molecule. The observation of higher rotational relaxation time in NaDC aggregates compared to NaTC aggregates clearly reflects that NaDC aggregates are more rigid due to its greater hydrophobicity and large in size, which is capable to bind the guest molecule more into their nanoconfined medium. Moreover, due to less acidic nature, NaDC aggregates have more ability to accept hydrogen bond from the LCM molecule and show the selective formation of isoalloxazine N10 anion (A1 monoanionic form) of LCM.

Surfactants induced release of a red emitting dye from the nanocavity of a molecular container: A spectroscopic and calorimetric study.

Supramolecular interaction of a red emitting dye Nile blue A (NBA) with Cucurbit[7]uril (CB7) in aqueous solution was studied and the release of the dye from the hydrophobic cavity of CB7 was reported. To investigate the supramolecular host-guest complex formation and release of dye, we have used the steady state absorption, fluorescence and time resolved fluorescence emission spectroscopy, (1)H NMR spectroscopy and isothermal titration calorimetry (ITC). The spectral properties of NBA were changed in the presence of CB7. The change in spectral features of NBA in presence of CB7 indicates the formation of supramolecular host-guest complexes. By using the SED equation the diameter of the complex was estimated. The complex formation further affirmed by the (1)H NMR study. Upfield and downfield shifts of the protons of NBA was observed in both the aliphatic and aromatic region. From the ITC measurement, we have drawn up the forces involved for the complexation of NBA with CB7. We have studied the release of NBA from the hydrophobic cavity of CB7 by using ionic, neutral surfactants and ionic liquid with the help of spectroscopic and calorimetric techniques. It is observed that on addition of SDS and ionic liquid (

Supramolecular interaction of a cancer cell photosensitizer in the nanocavity of cucurbit[7]uril: A spectroscopic and calorimetric study.

The interaction of small biologically active molecules in the nanocavity of supramolecular host is very interesting and thriving research area. In the presence of supramolecular host the absorption and emission properties of small biologically active molecules were modulated several folds compared to bulk solution. In this study we have investigated the supramolecular interaction of a cancer cell photosensitizer molecule harmane in the presence of cucurbit[7]uril (CB7) as host in aqueous buffer solution (pH∼7.2). We have used steady state absorption, emission and time resolved fluorescence spectroscopy techniques. The thermodynamics of the binding between harmane in the nanochannel of CB7 were studied by using isothermal titration calorimetry (ITC) method. The emission properties of harmane are modulated several fold in the presence of CB7. ITC study indicates that the complexation between harmane and CB7 are enthalpically favourable.

Photophysics and Rotational Dynamics of a Hydrophilic Molecule in a Room Temperature Ionic Liquid.

We have studied the photophysics and rotational diffusion of hydrophilic solute 7-(N, N'-diethylamino)coumarin-3-carboxylic acid (7-DCCA) in a room temperature ionic liquid methyltrioctylammonium bis(trifluoromethylsulfonyl) imide ([N1888 ][NTf2 ]). Comparison of activation energies of viscous flow and nonradiative decay shows that the photophysical properties of 7-DCCA are not guided by the bulk viscosity of the medium but are dependent on the specific solute solvent interaction and structural heterogeneity of the medium. The rotational relaxation behaviour of 7-DCCA in [N1888 ][NTf2] shows significant deviation from the Stokes Einstein Debye hydrodynamic model of rotational diffusion. This is indicative of the influence of specific solute solvent interaction on the rotational relaxation behaviour of 7-DCCA. Comparison of activation energy of rotational relaxation with activation energy of viscous flow clearly reinforces our assumption that the structural heterogeneity of the medium and specific solute solvent interaction plays a dominant role on the rotational diffusion instead of bulk viscosity.

Interaction of the nonsteroidal anti-inflammatory drug indomethacin with micelles and its release.

In this study, we have reported the binding interaction and photophysics of a nonsteroidal anti-inflammatory drug (NSAID) indomethacin (IMC) in the presence of different micelles. We have used several spectroscopic techniques such as UV-vis absorption, steady state fluorescence and time-resolved fluorescence emission spectroscopy. The spectral properties of IMC were modulated in the presence of micelles compared to that in neat water. The weak emitting drug molecule (IMC) becomes highly fluorescent after binding with the micelles. The fluorescence quantum yield and fluorescence lifetime increase in the presence of micelles compared to those in neat water. The isothermal titration calorimetry (ITC) method was used to study the binding interaction of IMC with different micelles. The thermodynamic parameters and the nature of binding between IMC and different micelles have been estimated. Moreover, addition of KCl salt in the respective micelles releases IMC molecule from the micelles to the aqueous medium. This study will help elicidate the binding behavior of IMC in the presence of different micelles for possible use as potential drug delivery systems.

Photophysics and rotational diffusion of hydrophilic molecule in polymer and polyols.

In this work we report the photophysics and rotational diffusion of a hydrophilic solute 7-(N,N'-diethylamino)coumarin-3-carboxylic acid (7-DCCA) in four protic solvents: poly(ethylene glycol), ethylene glycol, tetraethylene glycol, and glycerol, with variation of temperature. The cumulative effect of polarity, viscosity, and structural features of these solvents, as well as specific solute-solvent interaction on the photophysical properties of 7-DCCA was discussed. We observed significant differences in both steady-state and time-resolved emission properties. Estimation of activation energy of viscous flow and activation energy of nonradiative decay reinforce our assumption of a cumulative effect. It was observed that, in all solvents, H-bonding interactions are mainly responsible for changing the spectral properties. Study of rotational relaxation behavior demonstrates superstick boundary condition to be operative in ethylene glycol. It is due to the H-bonding interaction between 7-DCCA and ethylene glycol. Similarly, stick boundary condition is followed in case of tetraethylene glycol at 278 K and further from 293 K. Convergence to the stick boundary is observed in case of poly(ethylene glycol). These changes can be attributed to the change in structural organization in both poly(ethylene glycol) and tetraethylene glycol.

Supramolecular interactions of nonsteroidal anti-inflammatory drug in nanochannels of molecular containers: a spectroscopic, thermogravimetric and microscopic investigation.

Supramolecular host-guest complexation between the nonsteroidal anti-inflammatory drug indomethacin (IMC) and molecular containers were investigated. The weakly fluorescent drug molecule becomes highly fluorescent on complexation with different molecular containers, and time-resolved fluorescence emission spectroscopy reveals that the lifetime components of IMC significantly increase in the presence of molecular containers, compared with the lifetimes in neat water. The respective solid host-guest complexes were synthesised and characterised by Fourier transform infrared and (1) H nuclear magnetic resonance spectroscopic analysis. Microscopy techniques were used to analyse modifications of the surface morphology, owing to the formation of supramolecular complexes. The effect of the molecular container on the optical properties of IMC has also been investigated to determine the effect of nanochannels of different size and structure.

Sedative, antiepileptic and antipsychotic effects of Viscum album L. (Loranthaceae) in mice and rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Viscum album L. is claimed in traditional medical practice, to be useful in the treatment of epilepsy and insomnia in Himachal Pradesh, India. MATERIALS AND METHODS: The effect of Viscum album L. on epilepsy, psychosis and sedative activity was evaluated in mice and rats using standard procedure. RESULTS: The aqueous leaf extract of Viscum album L. prolonged the pentobarbital induced sleeping time and reduced the locomotor activity in actophotometer. This suggests that reduced locomotor activity facilitate GABAergic transmission. In addition the extract reduced MES, INH and PTZ-induced convulsions which suggest that there may be possibility of blocking Na(+) channels, opening of Cl(-) channels or enhancing the GABAergic system. The extract decreased the apomorphine-induced stereotyped behavior and potentiates the HAL-induced cataleptic score which suggests the extract possess antidopaminergic activity. CONCLUSION: The results obtained in present study suggested that title plant exhibited sedative, antiepileptic and antipsychotic activity in mice and rats.

Anti-diabetic potential of ursolic acid stearoyl glucoside: a new triterpenic gycosidic ester from Lantana camara.

A new stearoyl glucoside of ursolic acid, urs-12-en-3ß-ol-28-oic acid 3ß-D-glucopyranosyl-4'-octadecanoate and other compounds were isolated from the leaves of Lantana camara L. The structure of this new glycoside was elucidated and established by standard spectroscopic methods. In streptozotocin-induced diabetic rats it showed significant reduction in blood glucose level.

Patented herbal formulations and their therapeutic applications.

Recently, there is a greater global interest in non synthetic, natural medicines derived from plant sources due to better tolerance and minimum adverse drug reactions as compared to synthetic medicines. Herbal products are also commonly used by the patients with certain chronic medical conditions, including breast cancer, liver disease, human immunodeficiency, asthma and rheumatological disorders. WHO estimates that about three-quarters of the world's population currently uses herbs and other forms of traditional medicines for the treatment of various diseases. The herbs are formulated in different modern dosage forms, such as Tablets, Capsules, Topical cream, Gel, Ointment and even some novel drug delivery forms, like extended release, sustained release, and microencapsules dosage forms. Patenting of herbal formulations has increased over the past few years and scientific evidence of therapeutic activity has been reported by performing various in vitro and in vivo experiments. This manuscript deals with various patented herbal formulations with their therapeutic application against various diseases.

Status of novel drug delivery technology for phytotherapeutics.

Herbal medicines have been widely used all over the world since ancient times and have been recognized by physicians and patients for their better therapeutic value as they have fewer adverse effects as compared with modern medicines. However, phytotherapeutics needs a scientific approach to deliver the components in a sustained manner to increase patient compliance and avoid repeated administration. This can be achieved by designing novel drug delivery systems for herbal constituents. Novel drug delivery systems not only reduce the repeated administration to overcome non-compliance, but also help to increase the therapeutic value by reducing toxicity and increasing the bioavailability, and so on. Recently, pharmaceutical scientists have shifted their focus to designing a drug delivery system for herbal medicines using a scientific approach. For a long time herbal medicines were not considered for development as novel formulations owing to lack of scientific justification and processing difficulties, such as standardization, extraction and identification of individual drug components in complex polyherbal systems. However, modern phytopharmaceutical research solves the scientific needs for herbal medicines as in modern medicine, which gives way for developing novel formulations such as nanoparticles, microemulsions, matrix systems, solid dispersions, liposomes, solid lipid nanoparticles, and so on. This article summarizes various drug delivery technologies for herbal actives, which are gaining more attention for better therapeutic response.

User-driven health care: answering multidimensional information needs in individual patients utilizing post-EBM approaches: an operational model.

The hypothesis in the conceptual model was that a user-driven innovation in presently available information and communication technology infrastructure would be able to meet patient and health professional users information needs and help them attain better health outcomes. An operational model was created to plan a trial on a sample diabetic population utilizing a randomized control trial design, assigning one randomly selected group of diabetics to receive electronic information intervention and analyse if it would improve their health outcomes in comparison with a matched diabetic population who would only receive regular medical intervention. Diabetes was chosen for this particular trial, as it is a major chronic illness in Malaysia as elsewhere in the world. It is in essence a position paper for how the study concept should be organized to stimulate wider discussion prior to beginning the study.