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Evidence for the presence of selected diterpenoids from the methanol extracts of authenticated T. chamaedrys and T. canadense by LC/MS and NMR
Author(s) -
Sundaresan P Ramnathan,
Grundel Erich,
White Kevin D,
Mazzola Eugene,
Rader Jeanne I
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1020-c
Subject(s) - teucrium , chemistry , terpenoid , proton nmr , glycoside , high performance liquid chromatography , chromatography , methanol , carbon 13 nmr , organic chemistry , stereochemistry , botany , biology , lamiaceae
Plants of the Teucrium genus are rich in neo ‐clerodane diterpenoids. Germander, for example, has been used in traditional folk medicine for its stimulant, diuretic, antipyretic and antiseptic properties. However, the furano neo ‐clerodane diterpenoid, Teucrium A (TC‐1) present in Germander has been implicated in its in vivo hepatotoxicity. Methanol extracts of authenticated powdered plant material were prepared and analyzed by analytical HPLC. Dihydroteugin (TC‐2), teuflin (TC‐5), teuflidin (TC‐7) and teucvidin (TC‐6) were tentatively identified in the plant extracts by LC/MS and 1 H NMR experiments. A solid‐phase‐extraction method was adopted using styrene divinyl‐ benzene sorbent for the separation of TC‐1, TC‐5 and TC‐6 from chlorophyll and phenylpropanoid glycosides. Semi‐preparative HPLC yielded TC‐1, TC‐5 and TC‐6 in milligram quantities. One‐ and two‐dimensional NMR experiments have provided conclusive evidence for the existence of the diterpenoid compounds TC‐1, TC‐5 and TC‐6. All contain the distinctive teucrin furan system with proton NMR signals at ca, 7.5 and 6.4 ppm. In addition, the 1 H NMR spectra of isolated compounds compare closely with those of authentic standards and /or literature values. The analytical HPLC method for the isolation of selected diterpenoids is simple and sensitive. It can be used to detect the presence of germander in other dietary supplements.