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• One hundred and thirty eight plant species are recorded to treat eye disorders in traditional southern African medicine. • Pathogens associated with eye infections have been neglected. • Toxicity studies on many of the plant species are lacking. • No studies have focused on plant species to treat cataracts, glaucoma, macular degeneration, or diabetic retinopathy. • Sterility is a concern when administrating plant preparations directly into the eye. Ophthalmic infections are common and can cause substantial loss of eyesight. It is estimated that nearly 45% of the South African population has suffered from partial or total loss of eyesight with a substantial portion of this being due to infections. However, in approximately 80% of cases, this loss of eyesight could have been easily prevented or even treated. Multiple plant species are used in traditional South African medicine to treat eye infections, yet the therapeutic properties of most of these plants have been poorly studied. An extensive literature review of the ethnobotanical literature was undertaken to document the plant species used in southern African traditional medicine to treat eye disorders. A search was subsequently undertaken to identify and summarise studies that have provided some scientific evidence to support traditional use against these eye disorders. A total of 137 plant species belonging to 53 plant families are recorded to treat eye disorders in traditional southern African medicine. The use of many plants was credited with vague indications such as "eye problems" and "eye conditions". Only 42 of the identified species have been evaluated for inhibitory activity against any eye-related pathogens. Whilst bacterial Staphylococcal pathogens were the most extensively tested, many other pathogens associated with eye infections have been neglected. Additionally, several fungal and most viral pathogens have been completely neglected to date. Furthermore, few studies have tested the toxicity of the plant extracts and mechanistic studies are lacking. Whilst this review identifies and highlights plant species used in traditional southern African medicine to treat eye infections, substantially more research is required to completely validate their traditional use and to evaluate the potential of the plant preparations as drug leads. [ABSTRACT FROM AUTHOR]

Image, graphical abstract Recent increases in antibiotic resistance and corresponding decreases in the development of new antimicrobial therapies have made new antibiotic discovery a high priority. Traditional medicines have potential for antibiotic discovery, although synergistic combinations consisting of plant extracts and conventional antibiotics may be a more effective approach. The combinations may overcome resistance and repurpose antibiotics that would otherwise be ineffective against resistant bacterial strains. In this study, Terminalia sericea leaves were extracted with solvents of varying polarity and the resultant extracts were investigated for the ability to inhibit bacterial growth using disc diffusion and liquid dilution MIC techniques. The effects of combinations of the extracts and conventional antibiotics (chloramphenicol, ciprofloxacin, erythromycin, gentamycin, penicillin-G or tetracyclin) were also tested using the checkerboard method. Combinations that exhibited synergistic interactions were further examined using isobologram analysis to determine the ideal ratios of extract-antibiotic. Toxicity was evaluated using Artemia nauplii and human dermal fibroblast (HDF) toxicity assays. The methanolic and water T. sericea extracts were good inhibitors of the microbial triggers of several autoimmune diseases, with MIC values substantially <1000 µg/mL against all bacteria tested except P. aeurginosa. The extracts were particularly potent inhibitors of Proteus spp., with MICs as low as 180 µg/mL. However, combinations of T. sericea extracts and conventional antibiotics were substantially more effective in inhibiting the growth of some bacterial species. In total, four combinations were synergistic and a further eight combinations had additive effects. Although the mechanisms of potentiation are still unclear, compounds within T. sericea extracts may mimic the actions of resistance modifying agents, thus potentiating the activity of several antibiotics that are relatively ineffective alone. Isolation of these agents may be beneficial for drug design against the bacterial triggers of rheumatoid arthritis, ankylosing spondylitis, multiple sclerosis and rheumatic fever. All extracts, antibiotics and combinations were nontoxic in the Artemia nauplii and HDF toxicity assays, further indicating their potential for medicinal use. • Polar T. sericea extracts were strong inhibitors of bacterial growth when tested alone. • Some plant extract-antibiotic combinations were substantially more effective antibacterial agents. • Some weak antibiotics were substatially potentiated in combination with the extracts. • T. sericea extracts were nontoxic in A. nauplii and HDF assays. [ABSTRACT FROM AUTHOR]

Increasing bacterial resistance and a corresponding decrease in antibiotic discovery has made the development of new antibiotic therapies a high priority. Combinational approaches may be effective in overcoming resistance and potentiating the activity of conventional antibiotics that are otherwise ineffective against resistant bacteria. Moringa oleifera leaf, fruit pulp and seeds were extracted and investigated for the ability to inhibit bacterial growth using disc diffusion and liquid dilution MIC techniques. The extracts were also combined with conventional antibiotics and tested against the microbial triggers of some autoimmune diseases. Whilst some M. oleifera extracts were effective bacterial growth inhibitors, the majority had only low to moderate activity. The seed ethyl acetate and chloroform extracts were particularly noteworthy against Klebsiella pneumoniae (MICs of 976 and 402 μg/mL respectively) and against Proteus vulgaris (MICs of 500 and 938 μg/mL respectively). However, combinations of the M. oleifera extracts with conventional antibiotics proved substantially more effective. In total, 27 combinations were synergistic (18 against P. vulgaris , 1 against K. pneumoniae , 5 against Acinetobacter baylyi and 3 against Pseudomonas aeruginosa). Notably, several antibiotics with low inhibitory activity alone were returned to a state of substantial activity when tested in combination with the extracts. Moringa oleifera extracts may function as resistance modifying agents, potentiating the activity of several antibiotics that are relatively ineffective alone. Identification of these agents may be highly beneficial in drug design against several bacteria. • Moringa oleifera extracts were weak inhibitors of bacterial growth when tested alone. • Extract–antibiotic combinations were substantially more effective antibacterial agents. • Some weak antibiotics were substatially potentiated in combination with the extracts. • The M. oleifera extracts were nontoxic in A. nauplii and HDF assays. [ABSTRACT FROM AUTHOR]