Solid-state NMR analysis of steroidal conformation of 17α- and 17β-estradiol in the absence and presence of lipid environment

Cation ion specifically induces a conformational change in trans-dehydroandrosterone – A solid-state NMR study

“…Consequently, these methyl carbons behaved as unprotonated carbons. This phenomenon has been reported for other steroids [26,27]. Here we demonstrated that the selective detection of non-protonated and protonated signals in 13 C allowed us to assign the 13 C resonances of DHEA/Ca +2 mixtures.…”

“…zone, the 13 C resonances are well-resolved and free of any overlapping signals; in the upfield zone, particularly in the range of 20-40 ppm, the 13 C resonances, which stem from similar chemical environments, overlap. Similar spectral features have been reported for other steroids, such as hydrocortisone, prednisone, prednisolone [25], spironolactone [29], 17a-and 17b-estradiol [27], as well as vitamin D2 and D3 and their precursors [30].…”

“…The 13 C signals of the E2a/lipid spectrum revealed exclusively doublet patterns, whereas the 13 C signals of the E2/lipid spectrum revealed multiplet patterns, including doublet, triplet, or quartet. In contrast, singlet patterns were observed in the powdered form [27]. It has been demonstrated that the steroid compounds are not as rigid as often thought, and are flexible enough to adopt preferential conformations in the lipid environment.…”

“…In fact, high-resolution { 1 H} 13 C CP/MAS spectra have been obtained from a variety of steroids, including testosterone, hydrocortisone, trans-dehydroandrosterone (DHEA), spironolac- tone, vitamin D and other steroids, such as deflazacort and prednisolone tert-butylacetate, revealing conformation flexibility by multiplet patterns with splittings of 0.2-2.1 ppm, which are indicative of various steroid conformations [25,26]. In addition, solid-state NMR has been applied to 17a-estradiol (E2a), 17b-estradiol (E2), and, E2 and E2a mixed with 1,2-dimyristoyl-sn-glycero-3-phosphocholine/ 1,2-diheptanoyl-sn-glycero-3-phosphocholine (DMPC/DHPC) to probe steroidal ring conformations in a mimic lipid membrane environment [26,27]. The 13 C signals of the E2a/lipid spectrum revealed exclusively doublet patterns, whereas the 13 C signals of the E2/lipid spectrum revealed multiplet patterns, including doublet, triplet, or quartet.…”

Fingerprints of Phalaenopsis Tissues in Growth and Spike Induction Periods—A Solid‐state 13C NMR Approach

“…[15][16][17][18][19][20][21] By taking advantage of the broad chemical shift dispersion in 13 C and the normally short T 1 relaxation time in 1 H nuclei, { 1 H}/ 13 C cross-polarization combined with magic-angle spinning (CP/MAS) spectroscopy 22,23 has been routinely applied to insoluble synthetic polymers and natural products to study their morphologies, local conformations, and dynamic properties. [24][25][26][27][28] In plant studies, solid-state NMR techniques have been used to study the effects of hydration on the mobility of polysaccharides in the onion cell-wall 29 and to obtain structural information on young bamboo plants (Phyllostachys pubescens). 30 It has been…”