Low molecular weight gelators based on steroid derivatives and pentacyclic triterpenoids
The article is an overview of the latest achievements in the study of low molecular weight gelling agents based on steroids - cholesterol, estradiol, dehydroepi-androsterone and pentacyclic triterpenoids - arjunolic, glycyrrhetinic acids. These compounds are used as components of smart gels and are of interest for supramolecular chemistry. A gelling agent is a substance that is able to bind various solvents at low concentrations, and the resulting gel has a solid structure which rheological properties are similar to those of solids. Non-covalent interactions: dipole-dipole, van der Waals, electrostatic, hydrogen bonds and π-stacking, are considered as the driving forces for the formation a fibrous network by low molecular weight gelator. In contrast to decades of research into the gelation of polymers, proteins and inorganic substances, low molecular weight organic gelling agents have only recently begun to be actively studied. Their chemical structure is derived from urea, amino acids, carbohydrates, cholesterol and bile acids. Unlike steroid-based gels, information on the use of pentacyclic triterpenoids for the development of low molecular weight gelling agents is extremely limited. The interest in such systems is due to the fact that, like steroids, they have a developed, rigidly organized nanosized molecular platform, making them capable of self-association in polar and nonpolar organic solvents. In addition, the presence of molecules of these compounds in several functional groups that are easily chemically modified, low toxicity and biocompatibility allows them to be considered as promising starting materials for the pharmaceutical industry, in particular for the development of mild dosage forms.
Sangeetha, N. M.; Maitra, U. Supramolecular gels: Functions and uses. Chemical Society Reviews. 2005, 34, 821-836. https://doi.org/10.1039/B417081B.
Steed, J. W. Anion-tuned supramolecular gels: a natural evolution from urea supramolecular chemistry. Chemical Society Reviews. 2010, 39, 3686-3699. https://doi: 10.1039/b926219a.
George, M.; Weiss, R. G. Molecular organogels. Soft matter comprised of low-molecular-mass organic gelators and organic liquids. Accounts of Chemical Research. 2006, 39, 489-497. https://doi.org/10.1021/ar0500923.
Weiss, R.G.; Terech, P. Molecular gels: Materials with self-assembled fibrillar networks. The Netherlands: Academic Press. 2006.
Foster, J. A.; Piepenbrock, M-O. M.; Lloyd, G. O.; Clarke, N.; Howard, J. A. K.; Steed, J. W. Anion-switchable supramolecular gels for controlling pharmaceutical crystal growth. Nature Chemistry. 2010, 2, 1037-1043. https://doi.org/10.1038/nchem.859.
Hirst, A. R.; Escuder, В.; Miravet, J. F.; Smith, D. K. High-Tech Applications of Self-Assembling Supramolecular Nanostructured Gel-Phase Materials: From Regenerative Medicine to Electronic Devices. Angewandte Chemie International Edition. 2008, 47, 8002-8018. https://doi.org/10.1002/anie.200800022.
Sahoo, S.; Kumar, N.; Bhattacharya, C.; Sagiri, S. S.; Jain, K.; Pal, K.; Ray, S.S.; Nayak, B. Organogels: Properties and applications in drug delivery. Designed Monomers and Polymers. 2011, 14, 95-108. https://doi.org/10.1163/138577211X555721.
Dawn, A.; Shiraki, T.; Haraguchi, S.; Tamaru, S.-I.; Shinkai, S. What kind of “soft materials” can we design from molecular gels? Chemistry: An Asian Journal. 2011, 6, 266-282. https://doi.org/10.1002/asia.201000217
Goyal, H.; Pachisia, S.; Gupta, R. Systematic design of a low molecular weight gelator and its application in the sensing and retention of residual antibiotics. Crystal Growth and Design. 2020, 20, 6117-6128. https://doi.org/10.1021/acs.cgd.0c00820.
KaiQiang, L.; PanLi, H.; Yu, F. Progress in the studies of low-molecular mass gelators with unusual properties. Science China Chemistry. 2011, 54, 575-585. https://doi.org/10.1007/s11426-011-4250-x.
Kawano, S.; Fujita, N.; van Bommel, K. J. C.; Shinkai, S. Pyridine-containing cholesterols as versatile gelators of organic solvents and the subtle influence of Ag(I) on the gel stability. Chemistry Letters. 2003, 32,12-13. https://doi.org/10.1246/cl.2003.12.
Hishikawa, Y.; Sada, K.; Watanabe, R.; Miyata, M.; Hanabusa, K. A novel class of organogelator based on N-isopropylcholamide and the first observation of fibrous colloidal aggregates. Chemistry Letters. 1998, 795-796. https://doi.org/10.1246/cl.1998.795.
Maitra, U.; Kumar, V.P.; Chandra, N.; D’Souza, L.J.; Prasanna M. D.; Raju, A. R. First donor–acceptor interaction promoted gelation of organic fluids. Chemical Communication. 1999, 595-596. https://doi.org/10.1039/A809821B.
Pospieszny, T.; Koenig, H.; Kowalczyk, I.; Brycki, B. Synthesis, spectroscopic and theoretical studies of new quasi-podands from bile acid derivatives linked by 1,2,3-triazole rings. Molecules. 2014, 19, 2557-2570. https://doi.org/10.3390/molecules19022557.
Peng, J. X.; Liu, K. Q.; Liu, J.; Zhang, Q. H.; Feng, X. L.; Fang, Y. New dicholesteryl-based gelators: chiralty and spacer length effect. Langmuir. 2008, 24, 2992-3000. https://doi.org/10.1021/la703672u.
Peng, J.X.; Liu, K.Q.; Liu, X.F.; Xia, H.Y.; Liu, J.; Fang, Y. New dicholesteryl-based gelators: gelling ability and selective gelation of organic solvents from their mixtures with water at room temperature. New Journal of Chemistry. 2008, 32, 2218-2224. https://doi.org/10.1039/B807576J.
Liu, J.; He, P.L.; Yan, J.L.; Fang, X.H.; Peng, J.X.; Liu, K.Q.; Fang Y. An organometallic super-gelator with multiple-stimulus responsive properties. Advanced Materials. 2008, 20, 2508-2511. https://doi.org/10.1002/adma.200703195.
Yan, J.L.; Liu, J.; Sun, Y.H.; Jing, P; He, P.L.; Gao, D.; Fang, Y. Oligo (FcDC-co-CholDEA) with ferrocene in the main chain and cholesterol as a pendant group-Preparation and unusual properties. J Phys Chem B. 2010, 114, 13116-13120. https://doi.org/10.1021/jp1032838.
Gao, D.; Xue,M.; Peng, J.X.; Liu ,J.; Yan, N.; He, P.L.; Fang, Y. Preparation and gelling properties of sugar-contained low-molecular-mass gelators: combination of cholesterol and linear glucose. Tetrahedron. 2010, 66, 2961-2968. https://doi.org/10.1016/j.tet.2010.02.070.
Panja, A.; Ghosh, S.; Ghosh, K. A sulfonyl hydrazone cholesterol conjugate: gelation, anion interaction and its application in dye adsorption. New Journal of Chemistry. 2019, 43, 10270-10277. https://doi.org/10.1039/C8NJ05613G.
Gao, A.; Li, Y.; Lv, H.; Liu, D.; Zhao, N.; Ding, Q.; Cao, X. Melamine tunable effect in a lenalidomide-based supramolecular self-assembly system via hydrogen bonding. New Journal of Chemistry. 2017, 41, 7924-7931. https://doi.org/10.1039/C7NJ01374D.
Kuo, S.-Y.; Liu, C.-Y.; Balamurugan, R.; Zhang, Y.-S.; Fitriyani, S.; Liu, J. H. Dual-responsive ALS-type organogelators based on azobenzene-cholesteryl conjugates and their self-assemblies. New Journal of Chemistry. 2017, 41, 15555-15563. https://doi.org/10.1039/C7NJ03059B.
Ghosh, K.; Panja, A.; Panja, S. Cholesterol appended bis-1,2,3-triazoles as simple supramolecular gelators for the naked eye detection of Ag+, Cu2+ and Hg2+ ions. New Journal of Chemistry. 2016, 40, 3476-3483. https://doi.org/10.1039/C5NJ02771C.
Ramírez-López, P.; de la Torre, M. C.; Asenjo, M.; Ramírez-Castellanos, J.; González-Calbet, J. M.; Rodríguez-Gimeno, A.; Sierra, M. A. A new family of “clicked” estradiol-based low-molecular-weight gelators having highly symmetry-dependent gelation ability. Chemical Communications. 2011, 47, 10281-10283. https://doi.org/10.1039/C1CC13251B.
Bag, B. G.; Maity, G. C.; Pramanik, S. R. A terpenoid-based gelators: the first arjunolic acid derived organogelator for alcohols and mixed solvents. Supramolecular Chemistry. 2005, 17, 383-385. https://doi.org/10.1080/10610270500114640.
Bag, B. G.; Dinda, S. K.; Dey, P. P.; Mallia, V. A.; Weiss, R. G. Self-assembly of esters of arjunolic acid into fibrous networks and the properties of their organogels. Langmuir. 2009, 25, 8663-8671. https://doi.org/10.1021/la8042796.
Bag, B. G.; Maity, G. C.; Dinda, S. K. Donor-acceptor interaction promoted gelation: visual observation of color change. Organic Letters. 2006, 8, 5457-5461. https://doi.org/10.1021/ol062035v.
Lu, J.; Hu, J.; Song, Y.; Ju, Y. A new dual-responsive organogel based on uracil-appended glycyrrhetinic acid. Organic Letters. 2011, 13, 3372-3375. https://doi.org/10.1021/ol201129y.
Zhikol, O.A.; Shishkina, S.V.; Lipson, V.V.; Semenenko, A.N.; Mazepa, A.V.; Borisov, A.V.; Mateychenko, P.V. Low molecular weight supramolecular dehydroepiandrosterone-based gelators: synthesis and molecular modeling study. New Journal of Chemistry. 2019, 43, 13112–13121. https://doi:10.1039/C9NJ01390C