Scutellarein 4′-methyl ether glycosides as taxonomic markers in Teucridium and Tripora (Lamiaceae, Ajugoideae)

doi:10.1016/S0031-9422(02)00192-9

Phytochemistry

Volume 60, Issue 7, August 2002, Pages 727-731

https://doi.org/10.1016/S0031-9422(02)00192-9 Get rights and content

Abstract

The flavonoid profiles of two monotypic genera, Teucridium and Tripora, have been studied by analytical methods. These genera were formerly placed in the Verbenaceae, but are now classified in the Lamiaceae, subfamily Ajugoideae. The major flavonoids of both genera were identified as glycosides of scutellarein 4′-methyl ether (5,6,7-trihydroxy-4′methoxyflavone) and acacetin (5,7-dihydroxy-4′-methoxyflavone). The new flavone glycoside, scutellarein 4′-methyl ether 7-O-rutinoside, was isolated from Teucridium parvifolium and the rare scutellarein 4′-methyl ether 7-O-glucuronide from Tripora divaricata. The latter compound has only been reported previously in the related genus Clerodendron. The potential of these flavonoids as taxonomic markers for the tribe Ajugoideae is discussed.

The flavone glycosides scutellarein 4′-methyl ether 7-O-rutinoside and scutellarein 4′-methyl ether 7-O-glucuronide have been isolated from Teucridium parvifolium and Tripora divaricata, respectively. Their value as chemical characters in the taxonomy of the Ajugoideae is described.

Introduction

The taxonomic treatment of Teucridium parvifolium Hook.f. and Tripora divaricata (Maxim.) P.D.Cantino (=Caryopteris divaricata Maxim.) has changed many times during the last decade. Teucridium parvifolium is one of only four species of Lamiaceae native to New Zealand, which are all endemic (Allan, 1961). It is a woody shrub up to 2 m tall, with interlacing branches, small leaves and very small flowers, and is the only species in the genus Teucridium. Tripora is also a monotypic genus with a name derived from the triporate pollen of T. divaricata, a unique character in the Lamiaceae. Tripora, a tall herb native to China, Japan and Korea, was recently removed from Caryopteris, because this genus was found to be paraphyletic (Cantino et al., 1999). Teucridium and Caryopteris including Tripora were formerly classified in the family Verbenaceae, but later transferred to the newly created Lamiaceae subfamily Teucrioideae, together with a number of other genera (Cantino et al., 1992). Recently all the genera of the Teucrioideae were transferred to the subfamily Ajugoideae (Cantino et al., 1997), which now comprises ca. 850 species in 24 genera. These include Clerodendrum (500 spp.), Aegiphila (150 spp.), Teucrium (100 spp.), Ajuga (50 spp.), Oxera (23 spp.), Caryopteris (7 spp.), Faradaya (3 spp.) and the monotypic Huxleya, Oncinocalyx, Teucridium and Tripora. Evidence from chloroplast DNA sequences suggests that Teucridium is sister to the Australian genus Oncinocalyx and that these form a clade with the cosmopolitan genus Teucrium. Clerodendrum, Caryopteris, Tripora and Ajuga form a sister group to this clade (Wagstaff et al., 1998). To the best of our knowledge Teucridium parvifolium and Tripora divaricata have not yet been investigated for their flavonoid constituents. This paper describes the isolation and identification of flavonoids from these species and discusses their use in the chemosystematics of the Ajugoideae.

Section snippets

Results and discussion

Aqueous methanol extracts of Teucridium parvifolium and Tripora divaricata were analyzed by 2-D PC, HPLC with diode array detection and LC–MS using atmospheric pressure chemical ionisation (APCI). The flavonoids from the extracts of Teucridium parvifolium (1a, 2a, 3, 4a, 5) and Tripora divaricata (1b, 2b, 3, 4b, 6, 7) were isolated by means of preparative PC and semi-preparative HPLC. The short wavelength UV band of 1a (λ_max=285 nm) was typical of that of a flavone with hydroxylation at C-6 (

General

¹H NMR (500 MHz) and ¹³C NMR (125 and 67.8 MHz) spectra were recorded in DMSO-d₆ with the residual solvent resonances used as internal references at δ 2.50 and 39.5, respectively. ROE connectivities were measured using the 1D XSROESY pulse sequence (Gradwell et al., 1997). High-resolution ESI-MS (positive mode) were obtained on a Bruker Apex II instrument using internal calibrants. Positive ion first-order APCI-MS were obtained with a quadrupole ion-trap instrument (Finnigan LCQ) using a

Acknowledgements

Access to high field NMR facilities was kindly provided by the Medical Research Council, Biomedical NMR Centre, National Institute for Medical Research, Mill Hill, London, UK. We thank chemiSPEC (North of England Business and Innovation Centre, Sunderland Enterprise Park East, Sunderland, UK) for high-resolution MS data.

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In the context of phytochemistry, Lamiaceae can be unofficially divided into two major groups. The first one comprises all those species that mainly produce volatile terpenoids, found in the essential oils, while the second one comprises species that mainly biosynthesize components of the polar fraction. Typical examples of the first class are Salvia L., Mentha L., and Rosmarinus L. species, while typical examples of the second class are Ajuga L., Teucrium L., Melittis L., and Stachys L. species. Several phytochemicals have been isolated from Lamiaceae species, such as α- and β-pinene, menthol, and limonene among the essential oil constituents, and di- and triterpenes, flavonoids, and iridoids among the polar fraction constituents. Some of these compounds are even considered to be chemotaxonomic markers at the family, genus, and species levels.
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Phytochemistry

Abstract

Introduction

Section snippets

Results and discussion

General

Acknowledgements

References (19)

Applying excitation sculpting to construct singly and doubly selective 1D NMR experiments

Journal of Magnetic Resonance

Flavonoids and verbascoside as chemotaxonomic characters in the genera Oxera and Faradaya

Biochemical Systematics and Ecology

6-Hydroxyluteolin and scutellarein as phyletic markers in higher plants

Phytochemistry

A chemotaxonomic study of flavonoids from European Teucrium species

Phytochemistry

Distribution of 6-hydroxy-, 6-methoxy- and 8-hydroxyflavone glycosides in the Labiatae, the Scrophulariaceae and related families

Phytochemistry

4′-Methylscutellarein and pectolinarigenin from Clerodendrum inerme

Phytochemistry

Flora of New Zealand, Vol. 1

Genera of Labiatae: status and classification

A comparison of phylogenetic nomenclature with the current system: a botanical case study

Systematic Biology

Cited by (18)

Semi-synthesis of a series natural flavonoids and flavonoid glycosides from scutellarin

Isoscutellarein 8, 4′-Dimethyl ether glycosides as cytotoxic agents and chemotaxonomic markers in Kickxia aegyptiaca

Phytochemistry, Chemotaxonomy, Ethnopharmacology, and Nutraceutics of Lamiaceae

Evaluation of the hepatotoxic and hepatoprotective effect of Rwandese herbal drugs on in vivo (guinea pigs barbiturate-induced sleeping time) and in vitro (rat precision-cut liver slices, PCLS) models

Rosmarinic acid, scutellarein 4′-methyl ether 7-O-glucuronide and (16S)-coleon E are the main compounds responsible for the antiacetylcholinesterase and antioxidant activity in herbal tea of Plectranthus barbatus ("falso boldo")

Structure, Biological Activities and Metabolism of Flavonoid Glucuronides