R. K. Thappa

ESSENTIAL OIL OF FOUR HIMALAYAN NEPETA SPECIES

Abstract The chemical compositions of four Nepeta species collected from the Himalayan region of India have been determined for the first time by using a combination of GC, GC/MS and spectroscopic techniques. The oil of N. floccosa was found to be rich in neral (33.1%) and geranial (32.4%), N. govaniana oil contained 4aα, 7α, 7aα-nepetalactone (25.9%), germacrene D (20.5%) and β-elemene (17.5%) and N. discolor oil contained α-pinene (18.5%), β-pinene (12.6%), myrcene (10.7%) and linalyl acetate (12.3%). The oil of N. royleana was found to be rich in 1,8-cineole (75%)

Chemical Composition of Rose Water Volatiles

Abstract A volatile concentrate obtained from rose water (ex. Rosa damascena flowers) by liquid-liquid extraction with dichloromethane was studied by GC and GC/MS. The volatiles consisted mainly of 2-phenylethanol (69.7–81.6%), linalool (1.5–3.3%), citronellol (1.8–7.2%), nerol (0.2–4.2%), geraniol (0.9–7.0%) along with rose oxides and all other characteristic minor rose compounds.

Phenolic constituents of Iris milesii rhizomes

Abstract Analysis of a methanol extract of the rhizomes of Iris milesii resulted in the isolation of a new isoflavone, 5,6,7,4′-tetrahydroxy-8-methoxyisoflavone along with prunetin, sakuranetin, 2:6-dimethoxy-1,4-benzoquinone, tectorigenin, irigenin,4-β(D-glucosyloxy)-ferulic acid methyl ester, quercetin-3-methyl ether, tectoridin, iridin and iristectorin B.

Two pyrroloquinazolines from Adhatoda vasica

Abstract Two new pyrroloquinazoline alkaloids, viz. 1,2,3,9-tetrahydropyrrolo(2,1-b)-quinazolin-9-one-3 R -hydroxy-3(2′-dimethylamino phenyl (desmethoxyaniflorine) and 7-methoxy-3 R -hydroxy-1,2,3,9-tetrahydropyrrolo-[2,1-b]-quinazolin-9-one (7-methoxyvasicinone), together with several known compounds were isolated from the leaves of Adhatoda vasica . Their structures were established by spectroscopic and X-ray diffraction analyses.

Variability in the Essential Oil of Angelica glauca Edgew of Different Geographical Regions

Abstract The chemical composition of Angelica glauca Edqew (Fam. Apiaceae) root volatile, from various locations in Alpine Himalayas at different phenological stages of plant growth was investigated by using GC, GC/MS and spectroscopic techniques. Terpene hydrocarbons (methyl octene, limonene, β-phellendrene, β-pinene), phthalides [(Z)-3-butyli-dene phthalide (Z)- and (E)-ligustilide] and citronellyl acetate showed large quantitative variations from flowering to dormancy stage and as well from different geographical locations.

Chemosystematics of the Himalayan Elsholtzia

Abstract The chemical composition of the oils of five Elsholtzia species found in the Himalayan region of India have been determined using a combination of techniques such as SiO2 column chromatography, TLC, GC, GC/MS, 1H-NMR, 13C-NMR and IR. E. blanda oil was found to be rich in linalool (44.9%) and geranyl acetate (37.2%), E. fruticosa oil contained 1,8-cineole (18.0%), perillene (20.5%) and terpinen-4-ol (12.6%) while E. densa oil contained dehydroelsholtzia ketone (20.6%) and borneol (12.6%). The major component of E. incisa oil was thymol (70.6%). Two oils of E. ciliate were found to possess different compositions. One oil contained rosefuran (84.8%) as the major constituent, whereas the other oil was rich in dehydroelsholtzia ketone (65.2%).

Essential Oil Constituents of Himalayan Dracocephalum speciosum Benth

Abstract The chemical composition of the essential oil from the aerial parts of Dracocephalum speciosum Benth. growing wild in Alpine Himalayas was investigated by GC, GC/MS, 1H- and 13C-NMR spectroscopy. The oil was totally new and different from the oils of other Dracocephalum species. The major constituents were identified as cis- and trans- pinocarvyl acetate (5.7% and 60.5%, respectively).

A new triterpenic acid from the wood rotting fungi

Abstract A new triterpenic acid, assigned the trivial name polyporenic acid D, has been isolated from the wood rotting fungus Polyporus officinalis . It has been shown to have the structure 3α-hydroxy-4,4,14α-trimethyl-5α-ergosta-8, 24(28)-dien-26-oic acid.

Isoflavones of two Iris species

Abstract Analysis of the methanol extracts of the rhizomes of Iris milesii resulted in the isolation of a new isoflavone, 5,6,7,4′-tetrahydroxy-3′-methoxyisoflavone and that of Iris kumaonensis , iriskumaonin methyl ether, iriskumaonin, irisflorentin, junipegenin-A, irigenin and iridin.