Antibacterial activities of both combined and individual medicinal plants extracts traditionally used to treat pneumonia

Pneumonia is one of the five major leading causes of death in children under-fives years and the elderly worldwide. Antibiotics used for its treatment are less potent due to bacteria development of bacteria resistant to antibiotics. This has led to a surge in search of novel drugs. There are already some drugs in clinical use that have natural products and derivatives such as quinine, morphine, vincristine, and taxol among others. The healing value of medicinal plants has been well accepted since Stone Age across the globe. This plant therapy has been prescribed and prepared independently or in combination. The following plants: Terminalia sericea, Warburgia salutaris, Dodonea angustofolia, Eucalyptus camaldulensis, Ballota africana, Kigelia africana and Acorus gramineus. These plants are most commonly used for treatment of pneumonia and other ailment, were studied to validate their antimicrobial activity based on scientific determination. The primary aim of this study was to evaluate the efficacy of these plants against bacteria pneumonia pathogens. Seven medicinal plants, independently and in combinations were relatively analysed for their antimicrobial activity against Staphylococcus aureus, Streptococcus pyogenes, and Klebsiella pneumoniae. Ground plant material of roots, bark and leafs were prepared with acetone, ethanol and distilled water. Dimethyl sulfoxide (10 &100%) was used as a reconstitution solvent and ciprofloxacin (10 %) as a positive control. The antimicrobial efficacy was determined using agar well diffusion and microtiter plate methods. Interaction between plants was evaluated by calculating fraction inhibitory concentration index (ΣFIC). Noteworthy activity for individual studies with all test organisms was observed with T. sericea. However, highest ZOI (30 mm) was observed for B. africana ethanol extract for S. pyogenes. Weak microbial activity was noted in W. salutaris and D. angustofolia extracts with all test organisms. Good antimicrobial activity was observed in combination studies with all organisms. The potency of different plant combinations varied with highest ZOI observed with B. africana and W. salutaris ranging from 33-35 mm, conversely ZOI of 35 mm was also noted for S. aureus in B. africana and E. camaldulensis ethanol extract. Noteworthy antimicrobial activity was observed in T. sericea and D. angustofolia against all test pathogens. weak antimicrobial activity with highest MICs was observed in combinations where W. salutaris was involved. After calculating ΣFICs, strongest synergistic effect was displayed for W. salutaris and D. angustofolia against all test organisms (lowest ΣFICs 0.0491). Most plant extract combinations, displayed either synergistic, additive or indifferent effect, with few demonstrating antagonistic interactions. Significant antagonism effect was noted for S. pyogenes with T. sericea ethanol extract ΣFIC value of 15.51. Based on results of this study use of plants in combination increase antimicrobial efficacy. The antimicrobial activities; synergistic and additive effects observed adds credibility in the use of plant combination for therapeutic value in treatment of pneumonia. Future studies are recommended to identify and isolate specific active compounds involved in plant combination interactions. The importance of combination studies for possible development of new antimicrobials that can succumb bacterial resistance need to be highlighted