BackgroundInfluenza infection remains a major health threat for animals and humans which crucially requires effective antiviral remedies. The usage of herbal medications as readily available alternatives for their compatibility with the body and fewer side effects compared to synthetic chemical treatments has become popular globally. The aim of this study was to investigate and screen in vitro anti-influenza activity of extracts of five South African medicinal plants, namely Tabernaemontana ventricosa, Cussonia spicata, Rapanea melanophloeos, Pittosporum viridiflorum and Clerodendrum glabrum, species which are used traditionally for the treatment of several diseases such as inflammatory and respiratory diseases.MethodsMethanol, ethanol (100% and 30%), acetone, hot and cold water extracts of the powdered plants leaves were obtained by standard methods. The cytotoxicity was determined by the MTT colorimetric assay on MDCK cells. The concentrations below CC50 values were tested for antiviral activity against influenza A virus (IAV) in different combination treatments. The effect of extracts on viral surface glycoproteins and viral titer were tested by HI and HA virological assays, respectively.ResultsBased on the applied methods, the most effective results against IAV were obtained from Rapanea melanophloeos methanol leaf extract (EC50 = 113.3 μg/ml) and Pittosporum viridiflorum methanol, 100% and 30% ethanol and acetone leaf extracts (EC50 values = 3.6, 3.4, 19.2, 82.3 μg/ml, respectively) in all types of combined treatments especially in pre- and post-penetration combined treatments with highly significant effects against viral titer (P ≤ 0.01).ConclusionThe outcomes offer for the first time a scientific basis for the use of extracts of Rapanea melanophloeos and Pittosporum viridiflorum against IAV. It is worth focusing on the isolation and identification of effective active compounds and elucidating the mechanism of action from these species. However, Tabernaemontana ventricosa, Cussonia spicata and Clerodendrum glabrum leaf extracts were ineffective in vitro in this study.Electronic supplementary materialThe online version of this article (10.1186/s12906-018-2184-y) contains supplementary material, which is available to authorized users.

No abstract

This paper reports on microneedles produced from biopolymer films extracted from fish scales of tilapia (Oreochromiss sp) using micromoulding technique. Evaluation of the properties of polypeptide films prepared from the fish scales gave refractive index (1.34), Protein concentration (78%), ash content (1.6%) at (22%) moisture content. The microneedles successfully inserted into artificial skin models and imaging using digital camera showed microneedles remained intact when inserted and when removed from the skin model. Microneedles also successfully inserted into porcine skin and were shown to dissolve gradually at 0s, 60s, 120s and 180s after insertion. Microneedles containing methylene blue as model drug were also produced and successfully pierced porcine skin. 3D finite element (FEM) simulations were carried out using the measured mechanical properties of the biopolymer films (Young's modulus 0.23N/mm2and tensile strength 1.8105N/mm2) to evaluate the stress distribution on various dimensions of the fish scale derived microneedles and hence, their ability to withstand force necessary to pierce the skin without fracture. Results from mechanical analysis using FEM showed that microneedles with tip radius between 10 and 100µm could withstand up to 0.12N of force per microneedle without fracture, which is indicated when the stress at the tip of the microneedle exceeds the ultimate stress of the material of fabrication. Using skin insertion tests and finite element simulations this study provides evidence that microneedles fabricated from fish scale biopolymer can effectively pierce and degrade into skin and therefore are good candidate for transdermal applications.