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Molecules ; 26(16)2021 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-34443601


Surfactant aggregates have long been considered as a tool to improve drug delivery and have been widely used in medical products. The pH-responsive aggregation behavior in anionic gemini surfactant 1,3-bis(N-dodecyl-N-propanesulfonate sodium)-propane (C12C3C12(SO3)2) and its mixture with a cationic monomeric surfactant cetyltrimethylammonium bromide (CTAB) have been investigated. The spherical-to-wormlike micelle transition was successfully realized in C12C3C12(SO3)2 through decreasing the pH, while the rheological properties were perfectly enhanced for the formation of wormlike micelles. Especially at 140 mM and pH 6.7, the mixture showed high viscoelasticity, and the maximum of the zero-shear viscosity reached 1530 Pa·s. Acting as a sulfobetaine zwitterionic gemini surfactant, the electrostatic attraction, the hydrogen bond and the short spacer of C12C3C12(SO3)2 molecules were all responsible for the significant micellar growth. Upon adding CTAB, the similar transition could also be realized at a low pH, and the further transformation to branched micelles occurred by adjusting the total concentration. Although the mixtures did not approach the viscosity maximum appearing in the C12C3C12(SO3)2 solution, CTAB addition is more favorable for viscosity enhancement in the wormlike-micelle region. The weakened charges of the headgroups in a catanionic mixed system minimizes the micellar spontaneous curvature and enhances the intermolecular hydrogen-bonding interaction between C12C3C12(SO3)2, facilitating the formation of a viscous solution, which would greatly induce entanglement and even the fusion of wormlike micelles, thus resulting in branched microstructures and a decline of viscosity.

Reologia , Tensoativos/química , Cetrimônio/química , Glutamatos/química , Concentração de Íons de Hidrogênio , Micelas , Viscosidade
Food Chem Toxicol ; 128: 119-128, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30926436


An immunologically active polysaccharide named as UPP-2 (1035.52 kDa) was isolated from Undaria pinnatifida using traditional water extraction followed by DEAE Sepharose fast flow chromatography. UPP-2 was proven to be a low sulfated polysaccharide with relatively abundant uronic acid (13.08 ±â€¯0.67%). UPP-2 mainly consisted of xylose (64.55%), glucose (23.81%), arabinose (5.90%) and mannose (4.26%), and its main glycosidic linkage types included →2)-α-D-Xylp-(1→, →4)-α-D-Glcp-(1→, α-D-Xylp-(1→ and →2,4)-ß-D-Xylp-(1 → . Results indicated that UPP-2 significantly promoted the proliferation and pinocytic capacity of RAW264.7 cells, and upregulated the mRNA expressions of iNOS, TNF-α, IL-6 and IL-1ß at 100-600 µg/mL with a maximum of 195, 42, 768 and 539 times of those of the negative control, respectively. Moreover, UPP-2 significantly increased the secretions of nitric oxide, TNF-α and IL-6 at 100-600 µg/mL (8.0, 73.1 and 188.7 times compared to those of the negative control, respectively), as well as promoted the production of IL-1ß obviously at 600 µg/mL. Overall, UPP-2 could be served as a potential dietary supplement or functional food based on its immunostimulatory activity.

Adjuvantes Imunológicos/química , Adjuvantes Imunológicos/farmacologia , Polissacarídeos/química , Polissacarídeos/farmacologia , Undaria/química , Animais , Configuração de Carboidratos , Interleucina-1beta/biossíntese , Interleucina-1beta/genética , Interleucina-6/biossíntese , Interleucina-6/genética , Camundongos , Peso Molecular , Óxido Nítrico/metabolismo , Óxido Nítrico Sintase Tipo II/biossíntese , Óxido Nítrico Sintase Tipo II/genética , Pinocitose/efeitos dos fármacos , Células RAW 264.7 , RNA Mensageiro/genética , Análise Espectral/métodos , Relação Estrutura-Atividade , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genética , Regulação para Cima/efeitos dos fármacos