Anti-bacterial studies on Hemigraphis colorata (Blume) H.G. Hallier and Elephantopus scaber L

To examine the ethanol, aqueous, chloroform, benzene, acetone and petroleum ether extracts of, Hemigraphis colorata (H. colorata) leaves and stem and Elephantopus scaber (E. scaber) leaves, root and flower for the presence of phyto-constituents and screened the anti-bacterial activity against the selected pathogens.

The fresh materials were shade dried and powdered using the tissue blender. The dried and powered materials (50 g) were extracted successively with 200 mL of aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether by using Soxhlet extractor for 8 h at a temperature not exceeding the boiling point of the solvent. Aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether extracts were prepared from powdered materials were used for preliminary phytochemical and antimicrobial studies using standard methods.

The crude aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether extracts E. scaber leaves, flower and root and H. colorata leaves and stem demonstrated that out of (5×6×12 = 360) tests for the presence or absence of the above compounds, 188 tests gave positive results and the remaining 172 gave negative results. The results of the phytochemical screening revealed that phenol (12/12), carbohydrates (9/12), steroids (8/12), saponins and coumarins (7/12), tannins (6/12), proteins (5/12), carboxylic acid and flavonoids (4/12), xanthoproteins (3/12) and alkaloids (2/12) presence in the crude aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether extracts of H. colorata leaves and stem. The crude aqueous, acetone, benzene, chloroform, ethanol, and petroleum ether extracts E. scaber leaves, flower and root displayed the presence of phenol (18/18), tannin (17/18), carbohydrates (16/18), steroids (14/18), carboxylic acid and coumarins (12/18), saponins (10/18), xanthoprotein (9/18), flavonoids (7/18), protein (4/18) and alkaloids (2/18). The root ethanolic extracts of E. scaber illustrated the highest zone of inhibition against three pathogens viz., Staphylococcus aureus (S. aureus) (24 mm), Escherichia coli (E. coli) (16 mm) and Pseudomonas aeruginosa (P. aeruginosa) (13 mm). The chlorofrom extracts of E. scaber showed the highest zone of inhibition against Bacillus cereus (B. cereus) (12 mm), The leaves ethanolic extracts of E. scaber demonstrated the highest zone of inhibition against three pathogens viz., Enterococcus faecalis (E. faecalis) (18 mm), Proteus mirabilis (P. mirabilis) (17 mm), Salmonella Typhi (S. typhi) (14 mm) and Enterobacter sp. (11 mm) While the benzene extracts of H. colorata demonstrated maximum zone of inhibition against the pathogen Acinetobacter sp. (14 mm) and S. aureus (12 mm).

It is hoped that this study would direct to the establishment of some compounds that could be used to invent new and more potent antimicrobial drugs of natural origin.