Numerous plants are known to exhibit considerable biological activities in the fields of medicine and agriculture, yet access to their active ingredients is often complicated, cumbersome and expensive. As a consequence, many plants harbouring potential drugs or green phyto-protectants go largely unnoticed, especially in poorer countries which, at the same time, are in desperate need of antimicrobial agents. As in the case of plants such as the Jericho tomato, Solanum incanum, and the common African tree Pterocarpus erinaceus, nanosizing of original plant materials may provide an interesting alternative to extensive extraction and isolation procedures. Indeed, it is straightforward to obtain considerable amounts of such common, often weed-like plants, and to mill the dried material to more or less uniform particles of microscopic and nanoscopic size. These particles exhibit activity against Steinernema feltiae or Escherichia coli, which is comparable to the ones seen for processed extracts of the same, respective plants. As S. feltiae is used as a model nematode indicative of possible phyto-protective uses in the agricultural arena, these findings also showcase the potential of nanosizing of crude “waste” plant materials for specific practical applications, especially—but not exclusively—in developing countries lacking a more sophisticated industrial infrastructure.

Aim/Background:The development of resistance to synthetic drugs by target organisms is a major challenge facing medicine, yet locked within plants are phytochemicals used in herbal medicine (especially in the Arabian Peninsula) that may find application in this regard. In pursuit of unlocking these “hidden treasures,” the methanol extracts of leaves, aerial parts, fruits, and resins of 17 plants used in the Arabian Peninsula were screened for antimicrobial activities.Materials and Methods:The nematicidal, antibacterial, and antifungal activities were determined using appropriate assays. Steinernema feltiae, Staphylococcus carnosus, Escherichia coli, and Saccharomyces cerevisiae were used as test organisms. Concentrations of the extracts ranging from 0.5 to 20 mg/ml were tested and appropriate statistical tests performed on the data generated.Results:The results show that extracts from Solanum incanum, Chenopodium murale, Commiphora myrrha, Anthemis nobilis, and Achillea biebersteinii were the most active and had very high activities against two or more of the test organisms at low concentrations. Extracts of the leaves of S. incanum and resins of Ferula asafoetida were the most active nematicides, with significant activity at 0.5 mg/ml. Extracts of C. myrrha and C. murale had the most active antibacterial activity with inhibition zones of 12-15 mm and minimum inhibitory concentrations (MICs) of 2.5 mg/ml for both bacteria. Extracts of the leaves of A. biebersteinii were the most active fungicide, giving an MIC of 1.5 mg/ml.Conclusion:The results validate the use of these plants in ethnopharmacology, and open new vistas of opportunities for the development of cheap but effective agents that may be useful against infectious diseases.

Objective: The present study assessed the antifungal activity of silver nanoparticles against oral candidiasis induced, in immunosuppressed male rats, using Candida albicans (ATCC 90028). Materials and Methods:One hundred and ninety two rats were assigned into six groups of 32 rats each. Rats in Group 1 (normal control) were immunosuppressed, but not infected with C. albicans. Those in Group 2 (negative control) were infected with the fungus. Rats in Groups 3 and 4 (test groups) were infected with C. albicans and treated topically with 50 µg/ml and 100 µg/ml silver nanoparticle solution, respectively. Those in Groups 5 and 6 (positive controls) were infected with the fungus, and treated topically with 2% miconazole oral gel and 2% miconazole aqueous suspension, respectively. All treatments were applied topically once daily for 2 weeks. Macroscopic evaluation of the candidal lesions, microbial counting and histopathological changes were evaluated on day 7, day 14 and the follow up assessment was performed at day 28.Results: Silver nanoparticles provided quicker and effective antifungal activity against mucosal C. albicans infection, compared to miconazole gel or suspension, at day 7. However, the silver nanoparticles were comparable to miconazole at the end of therapeutic period (day 14) and at the end of the follow up period (day 28). The microbiological data are corroborated by histological findings. Conclusion:Silver nanoparticles may be a promising candidate for the treatment of oral candidiasis. Additional studies are nonetheless warranted.

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