study of antibacterial and phytochemical properties of 12 herb extracts against pathogenic nocardia strains

the four full seasons & the various climates in our country iran, have certainly contributed to the variety of flora in iran, some of which demonstrate wonderful therapeutic effects. this is of particular interest when one considers such problems as antibiotic resistance and other side effects of synthetic drugs which have caused global interest in the growth of new disciplines such as pharmacognosy. in regard to important role of infectious disease in treating the life of people, and also inaccessibility to useful drugs with minor side effects, we decided to consider the ability of methanolic extract of 12 herbs in preventing the growth of bacteria.  for this purpose, we chose 2 strains of nocardia (n. asteroides and n. brasiliensis) as original bacteria. after performing phytochemical tests to determine the quality of flavonoids, alkaloids, tannin and saponin, nine concentrations of methanolic extract of 12 different herbal species were prepared. the organisms were cultured in their specific media and tempted the antibacterial properties of the extracts by means of distribution method in agar (drop - plate, disk plate, and well - plate).  after the distribution of herbal extracts in agar, the diameter of the clear zone formed has been measured, this is related to the ability of extract to prevent the growth of bacteria. according to the results, n. asteroides and n. brasiliensis, has nearly shown the same susceptibility to various concentrations of herbal extract (2.5, 5, 7.5 & 10 percent), and the complete clear zones proved that the extracts have significantly effective in controlling nocardia strains. due to the results, that were found the highly susceptible of nocardia strains to the herbal extracts, it is evident that these extracts contain antibacterial effects. it was found that the 6 medicinal plants out of the 12 herbs have potent antibacterial property. we came to this conclusion formed by 10% concentration of the above herbal extracts in appropriate distribution routs, were similar to that of the clear zones formed by specific antibiotic against nocardia species, e.g. amikacin, amoxicillin, ceftazidime, ceftizoxime / cefotaxime, cephalothin, cotrimoxazol.  the antibacterial activity of the above herbs is probably associated to the potency of strong antibacterial properties of alkaloids, flavonoids, saponins and tanans presents in the methanolic extraction of those six medicinal plants.