1.A fundamental investigation into aspects of the physiology and biochemistry of the stratum corneum in subjects with sensitive skin.
Raj N1, Voegeli R2, Rawlings AV1, Doppler S2, Imfeld D2, Munday MR1, Lane ME1. Int J Cosmet Sci. 2016 Apr 15. doi: 10.1111/ics.12334. [Epub ahead of print]
BACKGROUND: Sensitive skin is a poorly understood skin condition. Defects in stratum corneum (SC) barrier function and/or extrasensory neuronal networks in the epidermis are believed to be involved in the problem.
2.Coumarins from Angelica decursiva inhibit α-glucosidase activity and protein tyrosine phosphatase 1B.
Ali MY1, Jannat S1, Jung HA2, Jeong HO3, Chung HY3, Choi JS4. Chem Biol Interact. 2016 Apr 13. pii: S0009-2797(16)30143-0. doi: 10.1016/j.cbi.2016.04.020. [Epub ahead of print]
In the present study, we investigated the anti-diabetic potential of six natural coumarins, 4-hydroxy Pd-C-III (1), 4'-methoxy Pd-C-I (2), decursinol (3), decursidin (4), umbelliferone 6-carboxylic acid (5), and 2'-isopropyl psoralene (6) isolated from Angelica decursiva and evaluated their inhibitory activities against protein tyrosine phosphatase 1B (PTP1B), α-glucosidase, and ONOO--mediated protein tyrosine nitration. Coumarins 1-6 showed potent PTP1B and α-glucosidase inhibitory activities with ranges of IC50 values of 5.39-58.90 μM and 65.29-172.10 μM, respectively. In the kinetic study for PTP1B enzyme inhibition, compounds 1, 5, and 6 were competitive, whereas 2 and 4 showed mixed type, and 3 displayed noncompetitive type inhibition. For α-glucosidase enzyme inhibition, compounds 1 and 3 exhibited good mixed-type, while 2, 5, and 6 showed noncompetitive and 4 displayed competitive type inhibition. Furthermore, these coumarins also effectively suppressed ONOO--mediated tyrosine nitration in a dose-dependent manner.
3.Synergic application of spectroscopic and theoretical methods to the chlorogenic acid structure elucidation.
Marković S1, Tošović J2, Dimitrić Marković JM3. Spectrochim Acta A Mol Biomol Spectrosc. 2016 Apr 6;164:67-75. doi: 10.1016/j.saa.2016.03.044. [Epub ahead of print]
Although chlorogenic acid (5-O-caffeoylquinic acid, 5CQA) is a dietary polyphenol known for its pharmacological and nutritional properties, its structural features have not been completely elucidated. This is the first study whose aim is to contribute to clarification of the 5CQA structure by comparing the experimental and simulated IR, Raman, 1H NMR, 13C NMR, and UV spectra. For this purpose, a comprehensive conformational analysis of 5CQA was performed to reveal its most stable conformations in the gas-state and solution (DMSO and methanol). The lowest-energy conformers were used to predict the spectra at two levels of theory: B3LYP-D3/and M06-2X/6-311+G(d,p) in combination with the CPCM solvation model. Both methods provide very good agreement between all experimental and simulated spectra, thus indicating correct arrangement of the atoms in the 5CQA molecule. The quinic moiety is characterized with directed hydrogen bonds, where the carboxylic hydrogen is not oriented towards the carbonyl oxygen of the carboxylic group, but towards the oxygen of the proximate hydroxyl group.
4.A new approach in compatibilization of the poly(lactic acid)/thermoplastic starch (PLA/TPS) blends.
Akrami M1, Ghasemi I2, Azizi H1, Karrabi M1, Seyedabadi M3. Carbohydr Polym. 2016 Jun 25;144:254-62. doi: 10.1016/j.carbpol.2016.02.035. Epub 2016 Feb 23.
In this study, a new compatibilizer was synthesized to improve the compatibility of the poly(lactic acid)/thermoplastic starch blends. The compatibilizer was based on maleic anhydride grafted polyethylene glycol grafted starch (mPEG-g-St), and was characterized using Fourier transform infrared spectroscopy (FTIR), dynamic mechanical thermal analysis (DMTA) and back titration techniques. The results indicated successful accomplishment of the designed reactions and formation of a starch cored structure with many connections to m-PEG chains. To assess the performance of synthesized compatibilizer, several PLA/TPS blends were prepared using an internal mixer. Consequently, their morphology, dynamic-mechanical behavior, crystallization and mechanical properties were studied. The compatibilizer enhanced interfacial adhesion, possibly due to interaction between free end carboxylic acid groups of compatibilizer and active groups of TPS and PLA phases.
