Minor Labdane Diterpenes from Marrubium thessalum

Abstract

Five new labdane diterpenes, thessalines A, B, and D, 14β-hydroxythessaline A, and 14β-hydroxythessaline B (1-5, resp.) were isolated from the aerial parts of Marrubium thessalum, along with the known labdane diterpene deacetylvitexilactone (6) and the methoxylated flavones 4',7-dimethylapigenin and salvigenin. (3S,5R)-Loliolide was also found in the same source. Their structures were established by 1D- and 2D-NMR (COSY, HSQC, HMBC, NOESY, and ROESY) and MS analyses. The plant produces a great variety of labdane-type diterpenes, with variations in functionalities, particularly in the side chain. Their structures could be of chemotaxonomic significance for the genus Marrubium.

Polar Constituents of Marrubium thessalum Boiss. & Heldr. (Lamiaceae) and their Cytotoxic/Cytostatic Activity

“…The detailed analysis of the methanol extract of M. thessalum showed that it produces a vast spectrum of metabolites. Apart from the previously reported diterpenes (Argyropoulou et al ., , ), it was shown herein that significant amounts of phenylethanoid glycosides and flavonoids are also produced. The cytotoxic activity of the crude methanol extract may be attributed to these metabolites.…”

“…& Heldr. Previous phytochemical studies performed on M. thessalum revealed various new labdane diterpenes isolated from the dichloromethane extract (Argyropoulou et al ., , ). In the present work the antiproliferative effect of the methanol extract and the isolated compounds was evaluated against a panel of human cancer cell lines.…”

Antioxidant properties and phenolic variation in wild populations of Marrubium vulgare L. (Lamiaceae)

“…The antioxidant, cholinesterase inhibitory, antibacterial, analgesic, anti-inflammatory, anti-diabetic, and anti-oedematogenic activities of Marrubium extracts have been pharmacologically demonstrated in several modern studies (Orhan et al, 2010). The genus Marrubium is a rich source of diterpenoids, flavonoids and phenylethanoid glycosides (Argyropoulou et al, 2009(Argyropoulou et al, , 2011(Argyropoulou et al, , 2012Dendougui et al, 2011;Karioti et al, 2005Karioti et al, , 2007aPiozzi et al, 2006;Rigano et al, 2006;Takeda et al, 2000).…”

Labdane diterpenoids from Marrubium vulgare

“…Similarly, the presence of a furan ring was deduced from typical 1 H and/or 13 C NMR chemical shifts of two double bonds for 3-substituted furan ( Knöess and Zapp, 1998), as well as to satisfy the molecular formula. The typical axial-equatorial coupling constant (4.9 Hz) between H-5 and H-6 and NOESY interactions between H-6 and H-18 supported a b-orientation of the lactone (Argyropoulou et al, 2011). The NOESY interactions of b-oriented C-20 methyl protons b-orientations of H-8 and CH 2 -11.…”

“…Known compounds were identified as marrubiin (Knöess and Zapp, 1998), peregrinin (Khalil et al, 1996;Piozzi et al, 2006), thessaline D (Argyropoulou et al, 2011;Hussein et al, 2003), marrubinone B (Iida et al, 1995), deacetylvitexilactone (Argyropoulou et al, 2011;Rigano et al, 2009), verbascoside (Delazar et al, 2011), leucosceptoside A (Delazar et al, 2011), martynoside ( Sahin et al, 2004), anisofolin A (Rao et al, 1982), terniflorin ( Nawwar et al, 1989), and apigenin (Chen et al, 2013;Sang et al, 1998) based on their NMR and mass spectrometry data, as well as in comparison with those reported in the literature. 12(S)-Hydroxymarrubiin, 3-deoxo-15(S)-methoxyvelutine C, marrubiin, peregrinin, and marrubinone B were evaluated for in vitro antimicrobial activity against a panel of bacterial (Staphylococcus aureus ATCC 29213, methicillin-resistant S. aureus (MRSA) ATCC 33591, Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27853 and Mycobacterium intracellulare ATCC 23068) and fungal (Candida albicans ATCC 90028, C. glabrata ATCC 90030, C. krusei ATCC 6258, Cryptococcus neoformans ATCC 90113, and Aspergillus fumigatus ATCC 204305) strains.…”