Gloriosaols A and B, two novel phenolics from Yucca gloriosa: structural characterization and configurational assignment by a combined NMR-quantum mechanical strategy

Yucca: A medicinally significant genus with manifold therapeutic attributes

“…TEAC assay and ESIMS, NMR data confirmed that gloriosaols A-E extracted from Y. gloriosa has antioxidant activity. 11,12 Y. schidigera and Y. gloriosa roots and barks contained these bioactive phenolics. 13 The protective effects of Y. schidigera was assessed against oxidative damage induced by acute nitrite intoxication in murine models.…”

Quantum Mechanical Calculation of NMR Parameters in the Stereostructural Determination of Natural Products

“…The configurational assignment was further corroborated by analysis of the ROE cross-peaks on the basis of distances measured through careful examination of the calculated structures of the two diastereoisomers. [29] In particular, the distances of 3.31 and 4.50 Å between H-6Ј ring E and H-2 ring C together with the distances of 3.33 and 4.50 Å between H-6 ring D and H-2 ring H for stereoisomers 2 and 3, respectively, were in accordance with the presence of two expected cross-peaks observed in the ROESY spectra of gloriosaol A and the absence in the spectra of gloriosaol B.…”

“…Following the approach used for gloriosaols A and B, [29] the relative configurations of gloriosaols C-E were assigned by a combination of NMR analysis and quantum QM methods. In particular, these molecules were apparently not accompanied by their corresponding relative diastereoisomers, so the analysis of atropisomerism was not required.…”

“…In a stereoselective synthesis, for example, the reaction gives a small amount of a minor diastereoisomer along with the principal product, and identification of the major compound is a key step in optimizing the reaction yields and/or to proceed with the optimization of the synthesis. Mixtures of diastereoisomers can be isolated from natural sources, as reported for gloriosaols A and B [29] (section 2.2) and for other natural products. [46] Smith and Goodman, through analysis of a set of 28 pairs of diastereoisomers, have tried to verify the ability of QM calculation of NMR chemical shifts to distinguish between diastereomeric structures.…”

Determination of phenolic compounds in Yucca gloriosa bark and root by LC–MS/MS

“…This species is largely cultivated in eastern Georgia and was previously studied for its saponin content [12]. Studies oriented to the investigation of phenolic compounds led to the isolation of new phenolic constituents named gloriosaols A-E (8-12) [13,14], along with yuccaols C-E previously isolated from Y. schidigera [5][6][7]. Gloriosaols are spiro-structures made up of the same basic C15 and C14 structural units of yuccaols C-E but differing from yuccaols C-E in the occurrence of two C15 units instead of one.…”