Study on the antimicrobial activity of some medicinal plants and their effect on wound healing

Abstract

The relationship between man and plants has always been a very close one throughout the development of human culture. Plants have played an important role in the treatment of mans diseases and ailments. In their blossoms, seeds, leaves and roots are locked the secrets of life and death, power of healing or harm depending on how they are used. Many plants collected from different regions in Sudan were used for the treatment of different infectious disease, including septic wounds, which is a common disease in Sudanese people. Wound infection in diabetic patients was selected to investigate the antimicrobial activity of certain Sudanese medicinal plants against the etiological agents. Further more, the antibacterial effective substances of these plants were extracted and defined. In this study, two types of plants were tested. They included: Acacia nilotica (Garad) and Zizyphus spina-christi (Nabag). These plants were processed and extracted with different solvents. The chloroformic, methanolic and aqueous extracts of these plants were subjected to preliminary antibacterial screening against three standard organisms (Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa). The methanolic extract of Acacia nilotica showed high antibacterial activity against the three standard organisms. The study was a prospective, hospital and diabetic centers –based study. One hundred and thirty two clinical isolates were obtained from 100 cases, irrespective of their sex, (72%) were males and (28%) were females patients of different age. These specimens were collected from different sites. The feet were the commonest sites accounting for (81%), hands (12%), thigh (6%) and arm (1%). These clinical isolates were subjected to purification and identification. The results of identification showed that 43 isolates were Staphylococcus aureus, 18 Diphtheroids, 15 Proteus mirabilis, 12 Staphylococcus epidermidis, 10 Pseudomonas aeruginosa, 8 Enterococcus fecalis, 7 Clostridium iv perfringens, 5 each of E. coli and Klebsiella pneumoniae, 4 Streptococcus viridans, 3 Streptococcus pyogenes and 2 Staphylococcus saprophyticus. Mixed bacterial growth was obtained in 32% of the isolates. The methanolic extract of Acacia nilotica fruit (Garad) whole plant had bacteriocidal activity against (95%) of the isolated organisms. Aqueous extract of Acacia nilotica had bacteriocidal activity against (30%) of the isolated organisms and the chloroformic extract had no bacteriocidal activity against isolated organisms. The chloroformic and aqueous extracts of Zizyphus spinachristi showed no activity against isolated organisms, and the methanolic extract had bacteriocidal activity against (23%) of the isolated organisms. On the basis of its prominent antimicrobial profile against bacteria tested, methanolic extract of Acacia nilotica having the most significant antimicrobial activity compared with the other plants extracts. The effect of the Acacia nilotica methanolic extract invivo activity was tested on rats with infected wounds. Methanolic extract of Acacia nilotica was prepared in ointment of 2% (w/w) poly ethylene glycol. Tetracycline ointment 3% was used as standard control, both ointments were applied twice daily. In the first group of Albino rats whose infected wounds were not treated, healing was complete in 19 days, whereas in the second group of rats was infected wounds treated with 3% tetracycline ointment, 15 days were required for the completion of healing. In the third group of rats with infected wound treated with PEG ointment containing 2% Acacia nilotica methanolic extract, the healing period was reduced to 12 days. The methanolic extract of Acacia nilotica was more effective than the tetracycline ointment.