Search results for "Labdane"

Cytotoxic labdane diterpenes and bisflavonoid atropisomers from leaves of Araucaria bidwillii

2017

Abstract Chemical investigation of a methanolic extract of leaves from Araucaria bidwillii (Araucariaceae) from Egypt afforded four new labdane diterpenoidal metabolites (1–4) together with one known diterpene, 7-oxocallitrisic acid (5), two triterpenoidal metabolites, 2-O-acetyl-11-keto-boswellic acid (6) and β-sitosterol-3-O-glucopyranoside (7), phloretic acid (8), and two methylated bisflavonoids, agathisflavone-4′,7,7″-trimethyl ether (9) and cupressuflavone-4′,7,7″-trimethyl ether (10). The new metabolites 1–4 were unambiguously identified by applying extensive 1D and 2D NMR spectroscopic studies as well as HRESIMS. The relative and absolute configurations of 1–4 were determined using …

Labdane Diterpenes from Stachys plumosa

2000

Three new labdane diterpenoids were isolated from the aerial parts of Stachys plumosa. The first two (1, 2) were the dextrorotatory enantiomers of the known 6-deoxyandalusol and 13-epijabugodiol. Structures were determined using NMR and MS techniques. The absolute stereochemistry of the third compound (3) was not experimentally proved.

Phytochemical study of Cistus libanotis L.

2015

n continuation of our ongoing study on Mediterranean Flora, we focused the attention on Cistus genus. These plants possess interesting secondary metabolites and are used in many fields, principally in perfumery and more recently as raw material for food supplements (botanicals). n this article, we report the phytochemical analysis of Cistus libanotis L. from Tunisia. Among the diterpenes, labdane compounds resulted absent, in favour of two clerodanes, one of that never reported in Cistus sp. The main representative compounds were found to be several flavonoids with various grades of O-methylation. Other interesting components were two cinnamic esters of borneol, reported here for the first …

ChemInform Abstract: Photochemical Transformations of Some Neoclerodane and Labdane Diterpene Ketones.

2010

Some neoclerodane (2–4) and labdane (5 and 6) diterpene ketones having a β- or γ-hydroxy function, an α-epoxy group, or an α-olefinic double bond have been irradiated at λ = 313 nm in dry solvents (benzene or methanol). Fruticolone (2) yielded the naturally occurring 5,6-seco-neoclerodan-6,1α-olide derivative fruticolide (1), while hispanolone (5) gave the δ-lactone 8, both transformations involving a Norrish type I photoreaction. The α,β-unsaturated ketone derivative 4 was transformed into 7 by a stereoselective intramolecular [2+2] cycloaddition reaction involving its furanic 13(16)-double bond. Finally, the α-epoxy ketone 6 was rearranged to the 10(98)abeo-labda-7,9-dione derivative 10. …

Occurrence of (+)-6-desoxyandalusol in Stachys ionica and Stachys distans

2002

Antispasmodic Effects and Structure−Activity Relationships of Labdane Diterpenoids from Marrubium globosum ssp. libanoticum

2009

Marrubium globosum ssp. libanoticum is a medicinal plant used in Lebanon to reduce pain and smooth muscle spasms. A chloroform extract obtained from M. globosum aerial parts reduced acetylcholine-induced contractions in the isolated mouse ileum. The purification of this extract identified, among 12 isolated labdane diterpenoids, four new compounds, named 13-epicyllenin A (4), 13,15-diepicyllenin A (5), marrulibacetal (9), and marrulactone (11). Their structures were determined by spectroscopic methods. Compound 9, which exerted antispasmodic activity, is likely the active ingredient of the extract. Preliminary structure-activity relationships for this class of compounds are suggested.

Phytochemical and pharmacological studies on the acetonic extract of Marrubium globosum ssp. libanoticum

2006

A new natural labdane diterpene, marrulibanoside, was isolated from the acetonic extract of aerial parts of M. globosum Montbr. et Auch. ex Benth. ssp. libanoticum Boiss. (Lamiaceae). Its structure was determined by spectroscopic methods such as 1D and 2D NMR and mass spectrometry. Pharmacological studies have shown that the extract of M. globosum exerts anti-inflammatory effects in the rat paw oedema induced by carrageenin resulting in reduced paw swelling. This activity, which seems due to marrulibanoside, is a consequence of iNOS and COX-2 activities inhibition.

Molecular composition and chemotaxonomic aspects of Eocene amber from the Ameki Formation, Nigeria

2012

The molecular composition of fossil resin from the Eocene Ameki Formation, southern Nigeria has been analyzed by infrared spectroscopy, pyrolysis–gas chromatography–mass spectrometry and thermochemolysis gas chromatography–mass spectrometry to determine the structural class and botanical source of the resin. The pyrolysis products were dominated by bicyclic products derived from regular labdatriene structure and lacked succinic acid indicating Class Ib type amber. The biomarker compositions in the pyrolysates are dominated by sesquiterpenoids of the cadinane and bisabolane classes that are common constituents of higher plants and labdane type diterpenoids. The exclusive presence of labdane …

Synthesis and Biological Evaluation of Combretastatin A-4 and Three Combretastatin-Based Hybrids

2012

The syntheses of combretastatin A-4 from gallic acid and of three combretastatin-based hybrids are described. Starting from commercial gallic acid, the phosphonium salt (3,4,5-trimethoxybenzylphosphonium bromide) is synthesized and coupled, through a Wittig reaction, with several aldehydes, including methoxymethyl-protected isovanillin, the aldehyde γ-bicyclohomofarnesal having a labdane skeleton, 3-(3-pyridyl) propanal, and furfural. The biological properties of the cis-coupled compounds as cytotoxic, antiviral and antifungal agents are also reported. In addition, pyrogallol, gallic and 3,4,5-trimethoxybenzoic acids have been studied biologically.

The Diterpenoids from the Genus Hyptis (Lamiaceae)

2009

The genus Hyptis (family Lamiaceae) is known mainly for the essential oils isolated from the aerial parts of several species. Less known are the diterpenoids, extracted from a limited number of species. In consideration of the interest for the structures of this class of compounds, largely occurring in the whole Lamiaceae family, the present paper means to review and update their chemistry. Also the use of many species of Hyptis in folk-medicine is reported.