Microscopical, macroscopical studies, and GC/MS analysis of leaves and seeds hexane extract of Iraqi wild Amaranthus viridis L

Abstract

Medicinal herbs are the largest source of chemical compounds on the planet and are utilized as drugs of traditional medicine. Amaranthus viridis L, a herbaceous plant from Amaranthaceae family, has sparked a lot of interest in the field of folk medicine due to its diverse complex chemical content. Amaranthus viridis is known to include many of active phytochemicals e.g., tannins, resins, alkaloids and terpenes. However there is none or very little pharmacognostical reports about the macroscopical and microscopical study of plant parts. Aim: investigate the morphological characteristics of stems, leaves, and seeds, besides investigation of leaves under microscope to seek for the type of stomata and trichomes. In addition, the active ingredients in the leaves and seeds extract of Iraqi grown plant were estimated using gas chromatography/mass spectroscopy (GC/MS) analysis. Furthermore, this study aimed to extract the flavonoids from dried leaves and seeds using the hot extraction method, and these compounds were to be estimated using chromatographic methods such as thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). Methods: Amaranthus viridis L was collected from Al-Musayyib region, Iraq. The microscopical study was performed on fresh leaves and stems to assess the kinds of stomata and trichome. The plant seeds and leaves were extracted with n-hexane using the hot method, and the extract was analyzed using GC/MS analysis. For the extraction of the flavonoids, the defatted materials were re-extracted with ethanol 75% and partitioned with ethyl acetate, and the ethyl acetate layer investigated for the presence of flavonoids using both TLC and HPLC analysis. Results: the microscopical study exhibited that the plant has anomocytic type stomata with un-branched unicellular trichome. Eight compounds (5-methyl, 1-Undecane,2-Undecanone,6,10-dimethyl-hexahydropseudoionone,2-Pentadecanone, 6,10,14-Trimethyl-hexahydrofuransyl acetone, n-Hexadecanoic acid, Palmitaldehyde,diisopentyl acetal, Oleic acid , Pentafluoropropanoic acid, octadecyl ester , and Hexadecanoic acid ,2,3-dihydropropyl ester) were identified by the GC/MS analysis. Among these compounds two were identified to be pharmacologically active n-Hexadecanoic acid (palmitic acid) and oleic acid (omega-9-fatty acid). The most abundant compound in the hexane extract was n-Hexadecanoic acid with percent area of 28.36%. Both TLC and HPLC detected the existence of epicatechin in the ethyl acetate fraction of plant extract. Conclusion: The presence of many bioactive compounds in the Amaranthus viridis L explains the use of whole plant to eradicate different ailments traditionally. However, identification and isolation of individual phytochemicals and studying of their biological activities will definitely provide rich results. This is the first report about the microscopical characteristic of the Iraqi grown plant which considered as diagnostic parameters of this genus. In addition, the current study showed the existence of epicatechin in A.viridis L plant and the presence of such an important flavonoid with many important pharmacological activities is a very important discovery especially in the Iraqi grown plant and it needs further investigations and quantitative analysis.