High performance liquid chromatography and nuclear magnetic resonance analysis of longipinene derivatives from Stevia subpubescens var. intermedia

Abstract

The methodology for the separation of complex mixtures of longipin‐2‐ene‐7β, 9α‐diol‐1‐one diesters using high performance liquid chromatography followed by the identification of individual components by pulse Fourier transform 1H nuclear magnetic resonance spectroscopy is described. The identification methodology takes advantage of the spectral comparison between the isolated natural product and a wide series of previously prepared longipinene derivatives, and is applied to the study of the extracts of Stevia subpubescens var. intermedia which contain 11 previously isolated longipinene diesters and the new natural product longipin‐2‐ene‐7β, 9α‐diol‐1‐one 7‐seneciate‐9‐angelate.

Longipinane Derivatives from Stevia connata

“…Therefore, the angelate group was located at C-7 and the methylbutyrate group at C-8. The remaining 1 H and 13 C NMR data, given in the Experimental Section and in Table 1, respectively, indicated the presence of the longipinene moiety [2][3][4][5][6][7][8][9] in agreement with structure 1 (Chart 1).…”

“…Although its chemistry is not very uniform, the main secondary metabolites of the genus are sesquiterpene lactones, diterpenes, and longipinenes, as recently reviewed . Continuing the search for new substances from North American representatives of this genus, − we studied the hexane extracts of the roots of Stevia connata Lag. (Compositae), a wild shrub which grows in the mountains of the state of Michoacán, Mexico.…”

Natural sesquiterpenoids

“…These studies have been applied to the structural determination of a new sesquiterpene, 7-senecioate-9-angelate of 7P,9a-dihydroxylongipin-2-en-3one, which has been obtained from Stevia subpubescens. 97 The complete assignment of the lH NMR spectrum of the hydrocarbon longicyclene has been achieved. 98 10 Caryophyllane, Modhephane, and Silphiperfolane…”

Antifeedant and Cytotoxic Activity of Longipinane Derivatives

“…In conclusion, longipinanes 1-8 of proven absolute configuration are moderate-to-low insect antifeedants (1-3) with strong insect growth inhibition effects (1, 3-5, 8), and they exhibit moderate but selective cytotoxicity against H1299 lung carcinoma cells (2,6). In addition, VCD calculations, performed using the two hybrid functionals B3LYP and B3PW91 in combination with the DGDZVP basis set, show that the lower B3LYP level of theory provides sufficiently good data to ascertain the absolute configuration of the molecule, thereby saving the additional computer time required by the higher B3PW91 level of theory calculations.…”

“…Longipinane derivatives oxidized at C1, C7, C8, and/or C9, such as 1-8 (l " Fig. 1), are generally found as complex mixtures of esters [6]. The relative stereochemistry of the C7, C8, and C9 acyloxy groups at the seven-membered ring was established by singlecrystal X-ray diffraction of rastevione acetate (10) [7] and by chemical transformation of rastevione (9) in compounds of type 1 and 3 [8].…”