No abstract

No abstract

BackgroundPrevious reports showed that the Steroidal Glycoalkaloid Solamargine inhibited proliferation of non-melanoma skin cancer cells. However, Solamargine was not tested systematically on different types of melanoma cells and was not simultaneously tested on normal cells either. In this study we aimed to investigate the effect of Solamargine and the mechanism involved in inhibiting the growth of different types of melanoma cells.MethodsSolamargine effect was tested on normal cells and on another three melanoma cell lines. Vertical growth phase metastatic and primary melanoma cell lines WM239 and WM115, respectively and the radial growth phase benign melanoma cells WM35 were used. The half inhibitory concentration IC50 of Solamargine was determined using Alamarblue assay. The cellular and subcellular changes were assessed using light and Transmission Electron Microscope, respectively. The percentage of cells undergoing apoptosis and necrosis were measured using Flow cytometry. The different protein expression was detected and measured using western blotting. The efficacy of Solamargine was determined by performing the clonogenic assay. The data collected was analyzed statistically on the means of the triplicate of at least three independent repeated experiments using one-way ANOVA test for parametric data and Kruskal–Wallis for non-parametric data. Differences were considered significant when the P values were less than 0.05.ResultsHereby, we demonstrate that Solamargine rapidly, selectively and effectively inhibited the growth of metastatic and primary melanoma cells WM239 and WM115 respectively, with minimum effect on normal and benign WM35 cells. Solamargine caused cellular necrosis to the two malignant melanoma cell lines (WM115, WM239), by rapid induction of lysosomal membrane permeabilization as confirmed by cathepsin B upregulation which triggered the extrinsic mitochondrial death pathway represented by the release of cytochrome c and upregulation of TNFR1. Solamargine disrupted the intrinsic apoptosis pathway as revealed by the down regulation of hILP/XIAP, resulting in caspase-3 cleavage, upregulation of Bcl-xL, and Bcl2, and down regulation of Apaf-1 and Bax in WM115 and WM239 cells only. Solamargine showed high efficacy in vitro particularly against the vertical growth phase melanoma cells.ConclusionOur findings suggest that Solamargine is a promising anti-malignant melanoma drug which warrants further attention.Electronic supplementary materialThe online version of this article (doi:10.1186/s12935-016-0287-4) contains supplementary material, which is available to authorized users.

No abstract

A melissopalynological study of Omani honeys was undertaken to determine floral sources, and identify pollen types, that would indicate the ecological origins. The study comprised the analysis of 48 honey samples collected during 2001-2003 from 14 locations in the Muscat and Al Batinah regions of Oman. The beehives and nests examined were either those of Apis florea or Apis mellifera bee colonies. A total of 122 pollen types, representing 50 plant families, were identified. Each taxon was categorized as representing a major or minor source of nectar and pollen. Thirty-two honey samples are unifloral types, and the remaining 16 are multifloral. Honey is harvested twice a year in Oman, once in the summer and again in the winter. The pollen data indicate that Ziziphus spina-christi, Prosopis juliflora, Prosopis cineraria and constitute the chief nectar and pollen sources for honeybees in this area during the winter. By contrast during the summer, Acacia tortilis, Citrus sp., Maerua crassifolia, Phoenix dactylifera, Prosopis cineraria, and Prosopis juliflora are the more important nectar sources. This study has identified a wide range of foraging plant sources for honeybees and demonstrates adequate potential for expanding and sustaining beekeeping in Muscat, and in the Al Batinah region. A modern pollen reference collection of 105 local floral species enabled the identification of the pollen types. Seventy-four pollen types were found in the 48 honey samples. The identifications of pollen types are based on both light and scanning electron microscope (SEM) studies of the pollen in the honey and reference samples.