- *Corresponding Author:
- Saradha Vasanth
Loyoloa College, Chennai–600 034, India
E-mail: [email protected]
|Date of Submission||15 January 2002|
|Date of Revision||4 May 2005|
|Date of Acceptance||16 March 2006|
|Indian J Pharm Sci, 2006, 68 (2): 236-238|
The in vitro antibacterial activity of Hedyotis umbellata (aerial parts) was investigated against Staphyllococcus aureus, S. citreus, Streptococcus faecalis, Bacillus subtilis, Escherichia coli, Klebsiella aerogenes, Shigella flexneri, and Pseudomonas aeruginosa at 20 mg/ml, whereas the alcohol extract did not show any promising activity. The ethyl acetate eluate of the chloroform extract showed a zone of inhibition of 10mm against B. subtilis and E. coli , at 20 mg/ml.
The roots and leaves of Hedyotis umbellata Linn (Rubiaceae), known as Chay root, are considered to be expectorant, and are used in the treatment of asthma, bronchitis, and bronchial catarrh. A decoction of leaves is used as a wash for poisonous bites. The root bark, preferably of a two years old plant, is the source of Chay-root dye, once employed with mordant for imparting red colour to calico, wool, and silk fabcrics .
1, 2, 3-Trimethoxyanthraquinone, 1,3-dimethoxy-2-hydroxyanthraquinone, 1, 2-dimethoxyanthraquinone, 1-methoxy-2-hydroxyanthraquinone, 1,2-dihydroxyanthra-quinone, 1, 3-dimethoxyanthraquinone-2-O-glycoside, and ruberythric acid,were isolated from the roots of the plant .
The plant has been collected in Erode, Tamilnadu, and identified at the Botany Department of CSMDRIA, Chennai. The aerial parts of plant were cut, shade dried, coarsely powdered, and extracted with chloroform by cold percolation method (48h.), and then with ethanol (95%). The extracts were concentrated to dryness in vacuo. Chloroform extract was chromatographed over silica gel (100-200 mesh), (Acme) and eluted with hexane, benzene, ethyl acetate, and ethyl acetate-methanol (4:1).
The extracts were dissolved in DMF. The solutions were further diluted to get test solutions of required concentrations. Penicillin(10 Iu/disc, Himedia) for gram positive bacteria, and neomycin (30 μ/disc) for gram negative bacteria, were the standards used.
The antibacterial activity was assayed by streak plate and disc-diffusion methods [3,4]. Nutrient agar was employed as the medium. The in vitro screening was carried out using S. aureus, S. citreus, S. faecalis and B. subtili,s as gram positive bacteria,and E. coli, K. aerogenes, S. flexneri and P. aeruginosa, as gram negative bacteria. The nutrient agar containing the extract in different concentrations of 20,10,5 and 2 mg/ml, was poured into sterile petri dishes, and allowed to set. Different bacterial cultures were inoculated on the surface of the plates. The growth on the surface, means no activity. No growth on the surface, indicates activity of the trial drug at the particular concentration. The extract showing anti-bacterial activity was subjected to chromatography, and disc method was employed for eluates, for determining the activity. The disc diameter was 6 mm.
Results of the screening data were summarized in Tables 1 and 2. The alcohol extract did not show any promising activity, while chloroform extract showed activity against six bacterial strains (Table 1). The activity was noticed at a concentration of 10 mg/ml and above for S. aureus and S. citreus, and at 20 mg/ml for other bacteria, except B.subtilis and K.aerogenes. The hexane eluate of the chloroform extract showed a zone of inhibition of 8 mm at 10 mg/ml for E.coli. The ethyl acetate eluate was active against E-coli and B.subtilis at 20 mg/ml, showing a zone of inhibition of 10 mm. and against other strains, it was ineffective. Purification of the eluate yielded ursolic acid. This compound had been shown to be effective against S. aureus and B.subtilis .
|Bacterial strain||Concentration (mg/ml)|
|+ No activity, - activity|
Table 1: Antibacterial Activity Of Chloroform Extract Of Hedyotis Umbellata
|Bacterial strain||Zone of Inhibition in mm/disc|
|Hexane eluate||Benzene eluate||EtOAc eluate||EtOAc:CH3OH(4:1)||Standard|
NS – Not sensitive
Table 2: Antibacterial Activity of Column Eluates of Chloroform Extract of H. Umbellata at 20 mg/ml
The authors wish to thank Mr.V.Ramkumar for his help in the laboratory.
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