Optimization of antibacterial activity of ethanolic extracts of Eucalyptus tereticornis and Nigella sativa: Response surface Methodology.

The screening of plants for medicinal purposes represents an effort to discover newer, safer, and possibly more effective drugs. Design of the present study was made aiming to the optimization of the antibacterial activity of ethanolic extracts of Eucalyptus tereticornis (leaves) and Nigella sativa (seeds) against bacteria belongings to both Gram-positive (Bacillus subtilis and Staphylococcus aureus) and Gram-negative (Escherichia coli) spectrum by using response surface methodology. 20 g powder of each E. tereticornis (leaf) and N. sativa (seeds) were mixed with 200ml of ethanol at room temperature, and then it was centrifuged at 4000 rpm for 10 min to separate the supernatants, and allowed to dry in order to obtain ethanol free extracts. A fresh bacterial culture of 100µl of test microorganism was inoculated onto media and spread homogeneously. The antimicrobial activity of ethanolic extracts showed that all the concentrations tested were effective against the test microorganisms. The diameters of zones of inhibition exhibited by S. aureus PCSIR-83 were in the range of 0-28mm, E. coli PCSIR-102 (0-28mm) and B. subtilis PCSIR-05 (15-26mm). The combination of N. sativa (15mg/µl) and E. tereticornis (20mg/µl) were found most effective at pH 9.0 and temperature 35°C. Our results clearly indicate that Gram positive bacteria showed more sensitivity than Gram-negative bacteria.

Effect of fortified feed with olive leaves extract on the haematological and biochemical parameters of Oreochromis niloticus (Nile tilapia).

Olive leaves have been used traditionally to improve the immunity against several infections. Current study aimed to examine the effect of fortified feed with olive leaves extract on haematological and biochemical parameters of Oreochromis niloticus. Total 400 healthy fish were divided randomly into four groups and were cultured for two months in glass tanks of 250 L water capacity in triplicate. Fortified feed was prepared with various extract, 1%, 1.5% and 2% concentration in diet, while, control-group diet was without extraction. Results showed that all the haematological parameters including WBC, RBC, Hb, PCV and plasma protein were significantly increased while the biochemical parameters such as globulin albumen ratio increased in fish which fed on 1% of extract, but the level of cholesterol and triglycerides was decreasing by increasing the concentration of extract. It was concluded that olive leaves extract can be used to enhance the immunity, growth and health of fish.