Antimicrobial activity

In Ayurvedic and Unani medicine, Justicia adhatoda is a well-known medicinal herb. It is commonly known that higher plants contain antibacterial agents. The antimicrobial potential of Justicia adhatoda, alone makes a major contribution. An indicator of an antimicrobial agent's relative potential is the formation of a growth inhibition zone, which is a clear area surrounding the original agent and indicates the efficacy of the agent. The present study aimed to evaluate antimicrobial activity of at different concentrations (25, 50, 75 & 100 μg/ml) of methanol, pet ether and water extract of leaf, stem, root and flower part of J. adhatoda against Gram-negative (E. coli and P. syringe) and gram-positive (B. cereus and S. aureus) bacterial strains. Antibiotic was used as standard. Based on the data presented here in; for root, the largest zone of inhibition was found to be against B. cereus (13mm) in water extracts at 100 μg/ml concentration followed by against all other three bacteria with 12mm inhibition zone in methanol extract. For stem, the largest zone of inhibition was found to be against E. coli (17mm) in methanol extracts followed by against S. aureus with 16mm inhibition zone in methanol and water extracts (100 μg/ml concentration). In case of flower, the maximum inhibition Zone (IZ) was 17 mm against E. coli (in water extract) and S. aureus (in methanol extract) followed by P. syringe (methanol extract) with 15mm inhibition zone. For leaves, highest IZ was 17 mm against E. coli (in water extract) followed by S. aureus (in methanol and pet ether extract) with IZ of 15mm. So, this study provided referential information about the antimicrobial activity of different extracts of different parts of Justicia adhatoda L. It may be effective in identifying a new bioactive compound for the development of novel medications.

Cuscuta reflexa Roxb. is a parasitic plant having many medicinal properties and used as traditional medicine in Ayurveda for the treatment of various disorders. In the present research work, researchers have investigated antimicrobial ability of C. reflexa grown on Nerium oleander host plant successive extracts against selected human pathogenic bacteria. Escherichia coli (MTCC 730), Proteus vulgaris (MTCC 1771), Staphylococcus aureus (MTCC 7443), Bacillus subtilis (MTCC121) and Pseudomonas aeruginosa (MTCC 4673) were used as the test pathogens. Hot extraction technique was used to prepare the plant extracts. Antimicrobial activity was tested using disc diffusion method. Chloroform extract of Cuscuta reflexa grown on Nerium oleander host plant showed maximum activity against B. subtilis (20 mg/disc; IZ= 27mm, AI= 1.35), (10mg/disc; IZ= 25mm, AI= 1.3) which is more than the standard disc tetracycline. Chloroform extract also showed appreciable activity against P. vulgaris and P. aeruginosa. Ethyl acetate extract also showed maximum activity against P. aeruginosa (20mg/disc; IZ= 16mm, AI= 1.14) and E. coli (5 mg/disc; IZ= 22mm, AI= 1.1). Chloroform extract and ethyl acetate extract of C. reflexa grown on Nerium oleander host plant is capable to inhibit the growth of E. coli, B. subtilis and P. aeruginosa effectively. Therefore, these extracts can also be used for the isolation of pure compounds/ volatile compounds with potentials to be used as therapeutics.