Isoiridomyrmecin rich essential oil from Nepeta erecta Benth. and its antioxidant activity.

The essential oil composition of the aerial parts of Nepeta erecta Benth. (Family: Lamiaceae) from Uttarakhand, India was analysed by capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). A total of 34 constituents were identified representing 94.6% of the oil composition. Oxygenated monoterpenes (74.0%) constituted the major proportion of the oil, dominated by isoiridomyrmecin (70.6%) as a single major constituent. Other significant constituents were caryophyllene oxide (9.6%), ß-Bourbonene (2.0%), humulene epoxide II (1.7%) and linalool (1.0%). The in vitro antioxidant activity (AOA) was assessed using ß-Carotene bleaching assay, reducing power, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and inhibition of lipid peroxidation methods. The oil was found to exhibit AOA by inhibiting ß-Carotene bleaching (54.6 ± 2.52%) and by scavenging DPPH free radical (IC(50) = 0.74 ± 0.12 mg mL(-1)). The AOA of the essential oil of N. erecta and its major compound isoiridomyrmecin has not been reported so far.

Chemical diversity in Himalayan Elsholtzia species.

The terpenoid composition of essential oils from the leaves of five Elsholtzia species, viz., E. eriostachya Benth., E. cristata Willd., E. polystachya Benth., E. flava Benth., and E. pilosa Benth., collected from the Himalayan region (India), was examined by GC, GC/MS, and NMR analyses. Comparison of the results with previous reports revealed new chemotypes. Cluster analysis was carried out in order to discern the similarities and differences within the essential-oil compositions at their subspecies/chemotype level. Based on the major constituents of the essential oils, six chemical groups were obtained.

Terpenoid diversity in the leaf essential oils of Himalayan Lauraceae species.

The leaf terpenoid compositions of nine Lauraceae species, viz., Neolitsea pallens, Lindera pulcherrima, Dodecadenia grandiflora, Persea duthiei, Persea odoratissima, Persea gamblei, Phoebe lanceolata, Cinnamomum tamala, and Cinnamomum camphora, collected from the Himalayan region (India) were examined by GC, GC/MS, and NMR analyses in order to determine the similarities and differences among their volatile constituents. Furano-sesquiterpenoids were the principal constituents of N. pallens, L. pulcherrima, and D. grandiflora. (E)-Nerolidol, limonene, beta-pinene, and alpha-pinene were the major constituents of P. duthiei; alpha-pinene, sabinene, and beta-caryophyllene were predominant in P. odoratissima, while the oils of P. gamblei and P. lanceolata possessed beta-caryophyllene as common major constituent. C. camphora and C. tamala were marked by the presence of camphor and cinnamaldehyde, respectively. Cluster analysis of the oil composition was carried out in order to discern the differences and similarities within nine species of six genera of Lauraceae.