Total assignments of ¹H and ¹³C NMR spectra of isocatalpanol and a derivative of tecomaquinone

Abstract

Isocatalpanol and tecomaquinone I were obtained from roots of Lippia sidoides, a medicinal plant from northeast Brazil. Reduction of tecomaquinone I with NaBH4 yielded a new derivative. Structural elucidation was done on the basis of spectral data, mainly by high-field NMR and electron ionization mass spectrometry.

General Characteristics, Phytochemistry and Pharmacognosy of Lippia sidoides

“…3-O-acetyloleanolic acid, methyl 3,4dihydroxybenzoate, and the flavonoids quercetin, luteolin and taxifolin from the stems; glucoluteolin from the leaves; and isolariciresinol from the bark. In another study, a naphthoquinone named isocatalpanol was isolated from L. sidoides roots [21]. From stems, roots, and leaves of L. sidoides sampled in the Medicinal Plants Garden of the Federal University of Ceará, Almeida et al [22] isolated and identified β-sitosterol, naftoquinone, tecomaquinone, 4',5,7-trihydroxyflavanone, 3',4',5,7tetrahydroxyflavanone, 4',5,7-trihydroxy-6-methoxyflavone, 3,4,4',6' tetrahydroxydihydrochalcone-2'-O-β-D-glucopyranoside and 4,4',6'-trihydroxydihydrochalcone-2'-O-β-D-glucopyranoside (Figure 2).…”