Rasool Bakhsh Tareen

Compositional studies and Biological activities of Perovskia abrotanoides Kar. oils

BackgroundCurrent study has been designed to evaluate the chemical composition of essential and fixed oils from stem and leaves of Perovskia abrotanoides and antioxidant and antimicrobial activities of these oils.ResultsGC-MS analysis of essential oil identified 19 compounds with (E)-9-dodecenal being the major component in stem and hexadecanoic acid in leaves. In contrast, GC-MS analysis of fixed oil showed 40 constituents with α-amyrin the major component in stem and α-copaene in leaves. The antioxidant activity showed the highest value of 76.7% in essential oil from leaves in comparison with fixed oil from stem (45.9%) through inhibition of peroxidation in linoleic acid system. The antimicrobial assay tested on different microorganisms (e.g. E. coli, S. aureus, B. cereus, Nitrospira, S. epidermis, A. niger, A. flavus and C. albicans) showed the higher inhibition zone at essential oil from leaves (15.2 mm on B. cereus) as compared to fixed oil from stem (8.34 mm on S. aureus) and leaves (11.2 mm on S. aureus).ConclusionsThe present study revealed the fact that essential oil analyzed from Perovskia abrotanoides stem and leaves could be a promising source of natural products with potential antioxidant and antimicrobial activities, as compared to fixed oil.

Benzoic acid derivatives from Stocksia brahuica

Abstract Two new benzoic acid derivatives, ethyl 3,5-dihydroxy-4-methoxybenzoate and 2-hydroxy-3-methylbenzoic acid, have been isolated from the aerial parts of Stocksia brahuica. They have been identified by mass and NMR spectroscopy. 3,4,5-Trihydroxybenzoic acid, 3,4,5-trimethoxybenzoic acid, methyl 4-hydroxybenzoate and n-propyl 4-hydroxybenzoate have also been isolated for the first time from this source.

Haplophytin-A and B: the alkaloidal constituents of Haplophyllum acutifolium

During the phytochemical investigation of Haplophyllum acutifolium, two alkaloids named haplophytin-A (1) and B (2) have been obtained. In addition, some known constituents: flindersine (3), kusunokinin (4), beta-sitosterol, oleanolic acid, cholesterol and hexadecanoic acid, have also been obtained. The known constituents have never been obtained from this source. The structures of all the isolated constituents were elucidated by spectroscopic means. However, the structures of constituents 1 and 2 were further confirmed through HMBC technique.

New terpenoids from Stachys parviflora Benth

Two new triterpenoidal saponins were isolated from the n‐butanolic extract of Stachys parviflora (Lamiaceae). Their structures were elucidated on the basis of spectral data as stachyssaponin A; 3β, 15α, 19α, 21β, 22α‐pentahydroxyolean‐12‐ene‐28‐oic acid 3‐O‐{α‐L‐rhamnopyranosyl‐(1 → 3)‐β‐D‐glucopyranoside}‐22‐O‐{α‐L‐arabinofuranosyl‐(1 → 3)‐β‐D‐glucopyranoside} (1) and stachyssaponin B; 2β, 3β, 15α, 21β‐tetrahydroxyolean‐12‐ene‐28‐oic acid 2‐O‐[α‐L‐arabinofuranoside]‐3, 21‐bis‐O‐[β‐D‐glucopyranoside] (2). Copyright

Gnapholide: A New Guaiac-Dimer from Pulicaria Gnaphalodes (Asteraceae)

The ethyl acetate soluble part of the chloroform extract of Pulicaria gnaphalodes belonging to the family Asteraceae afforded a new sesquiterpene-dimer of guaiane class named as gnapholide and anabsinthin of the same skeleton. The structures of both the compounds were elucidated with the aid of spectroscopic techniques including 2D NMR.

CONSTITUENTS OF THE ESSENTIAL OIL OF PEROVSKIA ATRIPLICIFOLIA BENTH

The volatile constituents of Perovskia atriplicifolia Benth. (Lamiaceae), collected in Pakistan, have been characterized by means of GC, GC–MS and 13C-NMR spectroscopy. Out of 19 compounds identified in this oil, the monoterpenes, δ3-carene (22.3%) and 1,8-cineole (27.5%) amounted to 50% of the total oil. β-Caryophyllene (10.8%) and α-humulene (5.7%) were the dominant sesquiterpenes. Copyright

Absolute configuration of oplopanone derivatives from Serphidium stenocephalum: ECD spectra of acyclic ketones with front-octant contributions.

The electronic circular dichroism (ECD) spectra of two sesquiterpenoids (1 and 2) related to oplopanone, obtained from a methanolic extract of the plant Serphidium stenocephalum (Artemisia stenocephala), were measured and reproduced by means of time-dependent density functional theory (TDDFT) calculations, establishing their absolute configuration. The application of ketone octant rule for carbonyl n-π* ECD band to compounds 1 and 2, which include an acyclic carbonyl group, was critically assessed. The peculiar oplopanone skeleton makes a straightforward application of the octant rule impossible, because of the uncertainty related to the shape of the so-called third nodal surface separating front and back octants. The various group contributions to the carbonyl n-π* ECD band were estimated with TDDFT calculations on selected molecular models obtained by consecutive dissections from 1.

A new acylated flavone glycoside from the fruits of Stocksia brauhica

Phytochemical investigations of the fruits of Stocksia brauhica (Sapindaceae) resulted in the isolation of a new acylated flavone glycoside. Its structure of the new compound brauhenefloroside D (1) was established as 3-O-[(α-L-rhamnopyranosyl)oxy]-7-O-[(acetyl)-β-D-glucopyranosyl (1 → 4)]-[6-O-(4-hydroxy-E-cinnamoyl)-β-D-glucopyranosyl-(1 → 2)-α-L-rhamnopyranosyl)-oxy]-kaempferol. The structure elucidation of the new compound was based primarily on 1D and 2D NMR analysis, including COSY, HMBC and HMQC correlations.

Constituents of the Essential Oil of Zataria multiflora Boiss. from Pakistan

Abstract The chemical constituents of the essential oil of Zataria multiflora Boiss. (Labiatae) have been investigated by means of GC, GC/MS, 1H- and 13C-NMR techniques. The oil isolated from aerial parts of the plant consisted mostly of carvacrol (62.4%), methyl carvacrol (6.5%), carvacrol acetate (4.4%), p-cymene (7.1%) and γ-terpinene (5.6%). Among the sesquiterpenes identified in this oil, 9-aristolen-lα-ol (1.6%) was the most abundant compound.

Trichosides A and B, new withanolide glucosides from Tricholepis eburnea

Trichosides A (1) and B (2), new withanolide glucosides, have been isolated from the n-butanolic fraction of the 75% methanolic extract of aerial parts of Tricholepis eburnea. Their structures were elucidated through spectroscopic analysis including ESI-MS, 2D NMR and acid hydrolysis.