Amir Ahmed

Chemical composition and mechanisms underlying the spasmolytic and bronchodilatory properties of the essential oil of Nepeta cataria L.

AIM OF THE STUDY The study was aimed to investigate the chemical composition and pharmacological basis for traditional use of essential oil of Nepeta cataria L. (Limiaceae) (Nc.Oil) in gastrointestinal and respiratory disorders. MATERIALS AND METHODS Chemical analysis was carried out through GC-EIMS, 13C NMR and Kovats Retention Indices while pharmacological study was carried out in isolated tissues preparations. RESULTS Four major components; 1,8-cineol (21.00%), alpha-humulene (14.44%), alpha-pinene (10.43%) and geranyl acetate (8.21%) were identified among the 27 compounds in Nc.Oil. In isolated rabbit jejunum, Nc.Oil, papaverine and verapamil inhibited spontaneous and high K+(80 mM) precontractions, as well as shifted the Ca++ concentration-response curves (CRCs) to right, indicating calcium channel blocking activity. In isolated guinea-pig trachea, Nc.Oil and papaverine inhibited carbachol (1 microM) and K+ precontractions with similar potency, while verapamil was more potent against K+. Nc.Oil also potentiated isoprenaline inhibitory CRCs, similar to papaverine, indicating papaverine-like PDE inhibitor activity. In isolated guinea-pig atria, Nc.Oil caused cardiodepression at around 25-80 times higher concentrations, similar to papaverine. CONCLUSIONS These data indicate that Nepeta cataria possesses spasmolytic and myorelaxant activities mediated possibly through dual inhibition of calcium channels and PDE, which may explain its traditional use in colic, diarrhea, cough and asthma.

Studies on the Chemical Composition and Possible Mechanisms Underlying the Antispasmodic and Bronchodilatory Activities of the Essential Oil of Artemisia maritima L.

This study describes the chemical composition of the essential oil of Artemisia maritima (Am.Oil) and the pharmacological basis for its medicinal use in gut and airways disorders. Twenty five compounds, composing 93.7% of the oil, were identified; among these, chrysanthenyl propionate and elixene were identified for the first time from any Artemisia species. The Am.Oil (0.3–1.0 mg/mL) suppressed spontaneous and high K+ (80 mM)-induced contractions in isolated rabbit jejunum, suggestive of an antispasmodic effect mediated possibly through calcium channel blockade. The calcium channel blockade activity was confirmed when pre-treatment of the tissue with Am.Oil (0.01–0.03 mg/mL) shifted the Ca++ concentration-response curves to the right, similar to verapamil and papaverine. In isolated tracheal strips, Am.Oil inhibited carbachol (CCh; 1 μM)-induced contractions more than that induced by K+ and shifted the isoprenaline-induced inhibitory CRCs to the left, similar to papaverine, suggestive of potentiation, while, verapamil was more potent against K+ than CCh-induced contractions and had no potentiating effect on isoprenaline-induced inhibitory CRCs. These data indicate that the Am.Oil exhibited spasmolytic and bronchodilator activities mediated possibly through dual blockade of calcium channels and phosphodiesterase, which provides the pharmacological basis to the medicinal use of Artemisia maritima in colic, diarrhea and possibly asthma.

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

New phenethyl alcohol glycosides from Stachys parviflora.

Phytochemical investigations of the whole plant of Stachys parviflora (Lamiaceae) resulted in the isolation of two new phenethyl alcohol glycosides. The structures of the new compounds named parviflorosides A and B were established as 2-(3,4-dihydroxyphenyl)-ethyl-O-α-l-rhamnopyranosyl-(1 → 2)-4-O-E-caffeoyl-β-d-glucopyranoside (1) and 2-(3,4-dihydroxyphenyl)-ethyl-O-α-l-rhamnopyranosyl-(1 → 2)-6-O-E-caffeoyl-β-d-glucopyranoside (2), respectively. The structure elucidation of the new compounds was based primarily on 1D and 2D NMR analysis, including COSY, HMBC and HMQC correlations.

Urease inhibitory activity of ursane type sulfated saponins from the aerial parts of Zygophyllum fabago Linn

Five ursane type sulfated saponins have been isolated from the aerial parts of Zygophyllum fabago Linn. (locally called Chashum). The urease inhibitory effects of these compounds have been investigated for the first time as well as their molecular docking studies have also been carried out to check the structure-activity relationship. The IC50 values of these compounds could not be found due to paucity of the samples. The molecular docking studies were performed only for the most active compound mono sodium salt of 3β,23-di-O-sulfonyl-23-hydroxyurs-20(21)-en-28-oic acid 28-O-[β-D-glucopyranosyl] ester (Zygofaboside A; 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.

Brauhenefloroside E and F; acylated flavonol glycosides from Stocksia brauhica Linn

Two new acylated flavonol glycosides, 3‐O‐{[2‐O‐β‐D‐glucopyranosyl]‐3‐[O‐β‐D‐glucopyranosyl]‐4‐[(6‐O‐p‐coumaroyl)‐O‐β‐D‐glucopyranosyl]}‐α‐L‐rhamnopyranosyl‐kaempferol 7‐O‐α‐L‐rhamnopyranoside and 3‐O‐{2‐[(6‐O‐p‐coumaroyl)‐O‐β‐D‐glucopyranosyl]‐3‐[O‐β‐D‐glucopyranosyl]‐4‐[(6‐O‐p‐coumaroyl)‐O‐β‐D‐glucopyranosyl]}‐α‐L‐rhamnopyranosyl‐kaempferol 7‐O‐α‐L‐rhamnopyranoside, trivially named as brauhenefloroside E (1) and F (2), respectively, were isolated from the fruits of Stocksia brauhica and their structures were elucidated using spectroscopic methods, including 2D NMR experiments. Copyright

First GC-MS Study of Essential Oil from Salvia bucharica

Salvia, being the largest genus of the family Lamiaceae, is reported to include about 900 species, distributed globally [1]. This genus is famous for its medicinal properties that are useful in the treatment of heart disease, diarrhea, dysmenorrheal hemorrhoids, and amenorrhea. It also possesses antimicrobial, antiseptic, antifungal, and demulcent properties [1, 2]. Salvia bucharica M. Popov, locally called “Sursandah,” is a clump-forming perennial, suffruticose herb or undershrub. The stem is erect, sometimes purplish and ascends up to 60 cm. In Pakistan, it has restricted distribution and is only found in Baluchistan near Pishin, Loralai, and Quetta. Traditionally, the flowers of this plant are used to treat sore throat, while the whole plant is used as a cure for appendicitis [3–5]. The oil was studied first in 1932 by S. Kudryashev [6] but, to the best of our knowledge, no report on the essential oil analysis of Salvia bucharica exploiting GC-MS and 13C NMR and authenticating the identified constituents by RI is available in the scientific literature. Altogether, 25 components were identified, constituting about 93%. The major class of identified compound was oxygenated monoterpenes, constituting 50.7% of the total, with five members. Eight compounds (24.3% of oil) belong to the monoterpene, while the contribution of sesquiterpenes is 16.3%, representing 11 compounds. Only one oxygenated sesquiterpene contributing 1.6% was identified. No diterpenoid was identified from the essential oil of Salvia bucharica (Table 1). The chief constituents of the essential oil of Salvia buchrica are 1,8-cineole (26.3%), camphor (16.4%), -caryophyllene (10.9%), sabinene (9.2%), borneol (7.0%), camphene (6.2%), -pinene (3.9%), trans-ocimene (2.5%), and elixene (2.1%). Sesquiterpenoids belonging to humulane, seco-heliangolide, aromadendrane, cadinane, caryophyllane and chamigrane classes are identified in the studied essential oil of S. bucharica. Buchariol, having the basic skeleton of guiane; bucharioside, a glycoside; and buchariate, a p-hydroxybenzoate ester, have been isolated from this species [7, 8]. 1,8-Cineole, the aglycone of the bucharioside, was found as the major constituent of the studied essential oil. Due to the antimicrobial activity [9] and decongestive and antitussive effect [10], it is used in drug formulations and aromatherapy. The high concentration of 1,8-cineole in the essential oil makes this plant a potential candidate for a natural drug. The essential oil was extracted from the aerial parts of Salvia bucharica, collected by one of the author (R. B. Tareen) from Quetta, Pakistan. A voucher specimen (RBT-SB-05) is kept in the Herbarium of the Department of Botany, University of Baluchistan, Quetta. Plant material (850 g) was subjected to hydro-distillation for 4 h immediately after grinding. The particle size of the ground material was less then 2 mm. The apparatus used was as per British Pharmacopeia [11]. The essential oil was collected in Et2O. After drying over anhydrous Na2SO4, the oil was concentrated under N2 stream and was stored at 4 C in a dark amber vial. The yield of the oil (1.45 mL) was 0.17% v/w on a dry weight basis. The chemical composition of Salvia bucharica was investigated by GC-MS, GC-FID, and 13C NMR techniques, as reported earlier [2, 12, 13]. GC-FID was carried out on a Shimadzu gas chromatograph GC-17A with Shimadzu Class GC-10 software, equipped with an SPB-5® (30 m 0.53 mm, 0.50 m film thickness) capillary column. The analyses were performed at an initial temperature of 50 C for 5 min, then ramped up at 3 C/min to a temperature 210 C with final time 45 min. One microliter of diluted sample in Et2O with a splitting ratio of 1:50 was injected. The injector and FID were kept at 300 C.