A general report on the use of the Allium test as cytotoxicological and genotoxicological assay is proposed, with particular emphasis about the standardization of the test in several common applications. The intraspecific variation in Allium cepa has been overlooked, as in most investigations no mention is made about origin and denomination of the onion cultivar used. A standardization of the used material would allow a better generalization of the results, since we cannot be sure that all cultivars would give the same response. A more frequent use of transmission electron microscopy (TEM) investigation is proposed. Even if relatively time consuming and not available in all laboratories, it may help to better understand the mechanism of cytotoxicity, since many morphological characters may appear similar but be arisen from different processes observable only with TEM. About statistical testing, tests other than chi-squared may be used in case of a lower amount of data. The most commonly used statistical tests are the parametric tests ANOVA and Student’s t, and the non-parametric tests Kruskal–Wallis and Mann–Whitney U, for analysis of variance. Tests should be used also to assess the minimal sample dimension for obtaining significance, since data collection (microscope observation) appears to be one of the main bottle necks of the test. Also the use of the Allium test for testing liposomes and other nanovectors for drug delivery is proposed, in order to assess the cytotoxicity of these types of medium and the possible increase in cytotoxicity of the associated drug.
Just as with yeasts and animal cells, plant cells show several types of autophagy. Microautophagy is the uptake of cellular constituents by the vacuolar membrane. Although microautophagy seems frequent in plants it is not yet fully proven to occur. Macroautophagy occurs farther away from the vacuole. In plants it is performed by autolysosomes, which are considerably different from the autophagosomes found in yeasts and animal cells, as in plants these organelles contain hydrolases from the onset of their formation. Another type of autophagy in plant cells (called mega-autophagy or mega-autolysis) is the massive degradation of the cell at the end of one type of programmed cell death (PCD). Furthermore, evidence has been found for autophagy during degradation of specific proteins, and during the internal degeneration of chloroplasts. This paper gives a brief overview of the present knowledge on the ultrastructure of autophagic processes in plants.
Hawthorn (Crataegus monogyna Jacq.) is a wild edible fruit tree of the genus Crataegus, one of the most interesting genera of the Rosaceae family. This review is the first to consider, all together, the pharmaceutical, phytochemical, functional and therapeutic properties of C. monogyna based on numerous valuable secondary metabolites, including flavonoids, vitamin C, glycoside, anthocyanin, saponin, tannin and antioxidants. Previous reviews dealt with the properties of all species of the entire genera. We highlight the multi-therapeutic role that C. monogyna extracts could have in the treatment of different chronic and degenerative diseases, mainly focusing on flavonoids. In the first part of this comprehensive review, we describe the main botanical characteristics and summarize the studies which have been performed on the morphological and genetic characterization of the C. monogyna germplasm. In the second part, the key metabolites and their nutritional and pharmaceutical properties are described. This work could be an essential resource for promoting future therapeutic formulations based on this natural and potent bioactive plant extract.
30 December 2018 in Microscopy Research and Technique
New hemp (Cannabis sativa L.) strains developed by crossbreeding selected varieties represent a novel research topic worthy of attention and investigation. This study focused on the phytochemical characterization of nine hemp commercial cultivars. Hydrodistillation was performed in order to collect the essential oils (EO), and also the residual water and deterpenated biomass. The volatile fraction was analyzed by GC-FID, GC-MS, and SPME-GC-MS, revealing three main chemotypes. The polyphenolic profile was studied in the residual water and deterpenated biomass by spectrophotometric assays, and HPLC-DAD-MSn and 1H-NMR analyses. The latter were employed for quali–quantitative determination of cannabinoids in the deterpenated material in comparison with the one not subjected to hydrodistillation. In addition, the glandular and non-glandular indumentum of the nine commercial varieties was studied by means of light microscopy and scanning electron microscopy in the attempt to find a possible correlation with the phytochemical and morphological traits. The EO and residual water were found to be rich in monoterpene and sesquiterpene hydrocarbons, and flavonol glycosides, respectively, while the deterpenated material was found to be a source of neutral cannabinoids. The micromorphological survey allowed us to partly associate the phytochemistry of these varieties with the hair morphotypes. This research sheds light on the valorization of different products from the hydrodistillation of hemp varieties, namely, essential oil, residual water, and deterpenated biomass, which proved to be worthy of exploitation in industrial and health applications.