Comparative studies of volatile oil composition of Rhododendron anthopogon by hydrodistillation, supercritical carbon dioxide extraction and head space analysis.[Pubmed: 21854174]

Volatile oil composition of the leaves of Rhododendron anthopogon (Ericaceae) growing wild in alpine Western Himalaya was studied using different extraction techniques including SC-CO(2) extraction and hydrodistillation (HD). Results from different extraction methodologies were compared with headspace analysis (HS) and evaluated for the effectiveness of techniques in characterisation of various terpene categories and to assess their influence on the yield and composition of volatiles. Variability in constituents and in quantitative yields was observed. The results varied with different extraction methods. A total of 27 constituents in SC-CO(2) extraction, 31 in HD and 17 in HS analysis were identified. Constituents in SC-CO(2) and HD oils were identified by gas chromatography mass spectrometry analysis. SC-CO(2) extraction was carried out at 40°C and 140 bar pressure and the oil represented by major constituents as β-caryophyllene (5.96%), α-humulene (4.06%) and p-menthadiene-2,9-diol (7.28%); in HD, oil limonene (11.26%), β-caryophyllene (11.62%), α-humulene (7.22%), and E-nerolidol (5.83%) dominated the oil and in HS analysis, limonene (24.14%), γ-terpinene (40.73%), α-terpinene (4.92%), β-phellandrene (3.44%) and β-ocimene (7.15%) were present as major constituents.

Five monoterpenes from leaves of Rhododendron anthopogon.[Pubmed: 21171530]

A phytochemical investigation of the leaves of Rhododendron anthopogon revealed the presence of five known monoterpenes: ranhuadujuanine A (1), cannabiorcicyclolic acid (2), ranhuadujuanine B (3), ranhuadujuanine C (4) and ranhuadujuanine D (5). All compounds are firstly reported as natural products. The assignments of some 13C-signals of ranhuadujuanine A reported in the literature were revised on the basis of 2D-NMR spectra.

[Study on the chemical constituents in the volatile oils of the flowers of Tibetan medicine Rhododendron anthopogon].[Pubmed: 20518303]

To study the chemical constituents of the volatile oils from the flowers of Rhododendron anthopogon D. Don.

Chemical composition and biological properties of Rhododendron anthopogon essential oil.[Pubmed: 20428045]

The essential oil of Rhododendron anthopogon was investigated by GC-MS, and seventeen compounds (representing approximately 98% of the oil) were identified. The major components of the aerial parts of the oil were the monoterpenes alpha-pinene, beta-pinene, limonene and the sesquiterpene delta-cadinene. Biological studies revealed a weak topical anti-inflammatory activity; a significant killing effect against some Gram-positive reference strains: Staphylococcus aureus, Enterococcusfecalis, Bacillus subtilis was measured; Mycobacterium tuberculosis reference strain and a clinical isolate of Candida, C. pseudotropicalis were killed by as low as 0.04% (v/v) essential oil. Moreover, the oil was able to reduce cancer cell growth independently of the cell line and the treatment protocols used.