Preliminary Study of the Anticancer Applications of Mesoporous Materials Functionalized with the Natural Product Betulinic Acid

Abstract

Dehydrated MCM-41 (S1) was functionalized under nitrogen with 3-chloropropyltriethoxysilane (CPTS) and 3-aminopropyltriethoxysilane (APTS) by grafting in toluene at 80 °C over 48 h to give the corresponding materials S2 and S3, respectively. Subsequently, S2 and S3 were suspended in methanol and reacted in a nitrogen atmosphere with betulinic acid (BA) for 48 h at 65 °C (in the presence of the triethylamine of S2) to give the BA-functionalized materials S4 and S5. All materials studied were characterized by powder X-ray diffraction, X-ray fluorescence, nitrogen gas sorption, multinuclear MAS NMR spectroscopy, thermogravimetry, UV spectroscopy, IR, SEM, and TEM. To study the release of BA, S4 and S5 were suspended in solutions simulating various body pH conditions (pH 7.4, 5.5, and 3.0). Results of the quantification of BA release by HPLC for S4 show a pH-dependent and very slow BA release following a logarithmic tendency, while S5 behaves differently, also pH-dependent but, in this case, fast release of BA which requires only days for total release of the therapeutic compound. In addition, the cytotoxic activity of all synthesized materials against various cancer cell lines was studied. The results show the absence of an antiproliferative effect on the surfaces without BA S1-S3, while an antiproliferative effect was observed with S4 and S5 and was attributed to the release of BA in the medium.

Mesoporous silica nanoparticles functionalised with a photoactive ruthenium(ii) complex: exploring the formulation of a metal-based photodynamic therapy photosensitiser

“…This consists of a simple grafting reaction of 3-chloropropyltriethoxysilane on dehydrated (treated for 24 hours at 150 ºC under vacuum) MSN to give MSN-CL following reported procedures. 59,60 Subsequently, a functionalisation reaction with the ruthenium polypyridyl complex, [Ru(bipy) 2 -dppz-7-hydroxymethyl][PF 6 ] 2, was carried out using a theoretical 5% of Ru wt.% (Ru/MSN). The reaction was performed in the presence of triethylamine (1.5 equivalent per equivalent of ruthenium) to promote the deprotonation of the alcohol group of the polypyridyl ruthenium compound and elimination of triethylammonium chloride to give the covalently supported ruthenium complex.…”

Current development and applications of ordered mesoporous silicas and other sol–gel silica-based materials in food sample preparation for xenobiotics analysis

“…with different structures (cubic, 3D hexagonal, 2D hexagonal, 2D rectangular, etc.). On the other hand, the functionalization of these materials with organic groups offers a further possibility of tailoring their physical and chemical properties, and therefore these materials can potentially be used for different applications such as adsorption of contaminants [19,20], substance-delivery [21,22], sensor-development [23,24], chromatographic and electrophoretic separations [25,26], etc.…”

Mitochondria‐Targeted Triphenylphosphonium Conjugated C‐3 Modified Betulin: Synthesis, Antitumor Properties and Mechanism of Action

“…[9] Large efforts to modify 1 and 2 for new derivatives with varied bioactivities, especially the anticancer and anti-HIV activity, have been conducted. [10][11][12][13][14] Bevirimat (3, Figure 1), produced by simply esterifying the 3-OH group of 2 with 2,2-dimethylsuccinic acid, was identified as the first-in-class HIV maturation inhibitor with significant anti-HIV activity. [15] Bevirimat (3) has succeeded in clinical IIb in 2009.…”