Antimicrobial Studies on Extracts of Four Species of Stachys

The antimicrobial activity of the methanol extracts of the dried flowering aerial parts of Stachys byzantina, S. inflata, S. lavandulifolia and S. laxa (Labiatae) were studied using the disc diffusion method and determination of minimum inhibitory concentration (MIC) values against Staphylococcus aureus, Streptococcus sanguis, Escherichia coli, Pseudomonas aeroginosa, Klebsiella pneumoniae, Aspergilus niger and Candida albicans. The extracts of plants exhibited concentration-dependent antibacterial activity against the bacteria tested. The extracts were more active against Gram-positive microorganisms. The extracts, however, did not show any antifungal activity.

Lamb HM, Adkins JC.Letrozole: A review of its use in postmenopausal 2.
women with advanced breast cancer.HPLC method is sensitive and reproducible for the analysis of letrozole in pharmaceutical dosage forms within a short analysis time.exhibited concentration-dependent antibacterial activity against the bacteria tested.The extracts were more active against Gram-positive microorganisms.The extracts, however, did not show any antifungal activity.Key words: Antimicrobial, extract, Stachys, MIC in methanol and applied to a 6 mm diameter paper disc.The extracts were tested at 10, 50, 100, 250, 500, 750 and 1000 μg/disc.Inhibition zone diameters were measured after 24 h.Gentamicin (50 μg/disc), amikacin (3 μg/disc) and amphotericin B (100 μg/disc, Sigma) were used as positive controls.MICs were determined by the dilution method at concentrations of 10 μg/ml to 25 mg/ml of culture medium 6 .Gentamicin (2 mg/ml) and amphotericin B (100 μg/ml) were used as positive controls.
The yield of methanol extracts of Stachys byzantina, S. infl ata, S. lavandulifolia and S. laxa was 14.1%, 14.3%, 10.1% and 10.6% w/w, respectively.Tables 1 and 2 gives a summary of the results of the antimicrobial effects and MICs of Stachys species investigated.The methanol extracts of the dried flowering aerial parts of S. byzantina, S. inflata, S. lavandulifolia and S. laxa exhibited concentrationdependent antibacterial activity against bacteria tested.The methanol extracts were more active against Gram-positive microorganisms (Streptococcus sanguis and Staphylococcus aureus).The extracts, however, did not show antifungal activity.
In 2004 and 2005, the antimicrobial activity of some endemic Stachys species including S. sivasica, S. anamurensis, S. cydnia, S. aleurites and S. pinardii was reported; the methanol extracts of Stachys L. were effective only against bacteria tested 7,8 .In 2005, essential oils and ethanol extracts from the leaves and/or roots of 35 medicinal plants commonly used in Brazil were screened for antiCandida albicans activity; essential oils from 13 plants including S. byzantina showed anti-Candida activity; the ethanol extract was not effective at any of the concentrations tested 9 .
In the present study, the results concluded that the methanol extracts of these plants have a potential as source of antibacterial agent of natural origin.Preliminary phytochemical studies showed that the aerial parts of the genus Stachys contain fl avonoids.Flavonoids may be responsible for their antibacterial activity.Ebastine is a new generation of antihistamines which has potent and selective histamine H 1 -receptor antagonistic effect, but negligible anticholinergic and antiserotonergic properties 1-2 .Ebastine is effective for the treatment of chronic idiopathic urticaria and allergic diseases with once daily regimen, and the antihistaminic action is mainly induced by the active metabolite, carebastine that is rapidly generated in the small intestine and in the liver 3 .
To date, a couple of chromatographic methods have been reported to quantify ebastine and its metabolites in physiological sample 4 .Kang et al and Rohatagi et al, recently improved the assay methodology for ebastine and carebastine by using a tandem mass spectrometry in human plasma 4,5 .However, till date no assay procedure has been reported for the determination of this drug in pharmaceutical formulations.Hence, there is a need to develop a simple assay procedure for the determination of this drug in pharmaceutical formulations.The availability of an HPLC method with high sensitivity and selectivity would be very useful for the determination of ebastine in pharmaceutical dosage forms.
Ebastine (assigned purity 99.8%) was a gift sample from Eros Pharma, Bangalore, India.HPLC grade methanol and water were procured from Ranbaxy Fine Chemicals Limited, SAS Nagar, India and Qualigens Chemicals, India respectively.Commercially available ebastine tablets, claimed to contain 10 and 20 mg of ebastine, respectively, were procured from the local Pharmacy.Quantitative HPLC was performed on an isocratic high pressure liquid chromatograph (Shimadzu HPLC Class 10A Series) with two LC-10AT pumps, using a fixed wavelength guided by a programmable UV/Vis detector (SPD-10A).The column used was Phenomenex RP-C18 (250 mm × 4.6 mm i.d., Particle size 5 µ ).The HPLC system was equipped with the software, Class LC-10AT series, version 5.03 (Shimadzu).
For HPLC, the mobile phase, methanol:water (90:10), was fi ltered before use through a 0.45 µm membrane filter.It was degassed with a helium spurge for 15 min and pumped from the respective solvent reservoirs to the column at a fl ow rate of 1.5 ml/min.The run

Accepted 23 June 2008 Revised 24 December 2007 Received 23 April 2007 Indian J. Pharm. Sci., 2008, 70 (3): 401-403
The sub cosmopolitan genus Stachys compromises more than 270 species and is justifi ably considered as one of the largest genera of the Labiatae 1 .The genus Stachys includes 34 species in Iran 2 .Phytochemical investigations of Stachys species have shown the occurrence of fl avonoids, diterpenes, phenyl ethanoid glycosides and saponins 3 .Plants of this genus have long been applied to treat genital tumors, sclerosis of the spleen, infl ammatory tumors and cancerous ulcers 4 .S. byzantina C. Koch.(syn.S. lanata Jacq.), S. infl ata Benth., S. lavandulifolia Vahl and S. laxa Boiss.and Buhse are aromatic plants, which grow in Azerbaijan, Golestan, Khorasan, Mazandaran and Tehran provinces of Iran 5 .A bibliographical survey showed that there were no reports on the antimicrobial activity of these species.In continuation of studies of Iranian species of the Labiatae family, we have had occasion to investigate the antimicrobial activity of S. byzantina, S. infl ata, S. lavandulifolia and S. laxa.

TABLE 1 : ANTIMICROBIAL ACTIVITY OF THE METHANOL EXTRACTS OF STACHYS BYZANTINA, S. INFLATA, S. LAVANDULIFOLIA AND S. LAXA*
*Zone of inhibition, including the diameter of the fi lter paper disc (6 mm); mean value of eight independent experiments; gentamicin, amikacin and amphotericin B were used as positive controls; -no inhibition.