Therapeutic and medicinal effects of snowdrop (Galanthus spp.) in Alzheimer's disease: A review.

Genus Galanthus (Amaryllidaceae) is an early spring flowering bulbous plant. Galanthus species contain alkaloids that have shown pharmacological activity. Galanthamine is an alkaloid that was extracted from Galanthus and other Amaryllidaceae. Owing to its acetylcholinesterase (AChE) inhibitory activity, galanthamine is used and marketed to treat Alzheimer's disease (AD). The aim of the present study, while introducing the botanical and pharmacological characteristics and various aspects of the medicinal plant Galanthus, is to emphasize the effect of this plant in the treatment of AD. In this web-based study in 2021, articles indexed in scientific databases in English language, including ISI Web of Knowledge, PubMed, Scopus, MedLib, Medknow, SID, ISC, and also articles and e-books published in Springer, Elsevier, John Wiley and Sons, and Taylor and Francis were evaluated from 1990 to 2021, using the following keywords: "Galanthus" "galanthamine," "Alzheimer's disease." Amaryllidaceae-type alkaloids possess an anticholinesterase activity. The most studied Galanthus alkaloid, galanthamine, is a long-acting, selective, reversible, competitive inhibitor of AChE and an allosteric modulator of the neuronal nicotinic receptor for acetylcholine (ACh). Owing to its AChE inhibitory activity, galanthamine is used to treat certain stages of AD. Galantamine can act as a parasympathomimetic agent, especially as a reversible cholinesterase inhibitor. Galantamine is not structurally associated with other AChE inhibitors. Hence, its proposed mechanism of action involves the reversible inhibition of AChE, preventing hydrolysis of ACh that results in an increased concentration of ACh at cholinergic synapses.

Foliar-applied selenium nanoparticles alleviate cadmium stress through changes in physio-biochemical status and essential oil profile of coriander (Coriandrum sativum L.) leaves.

Since large areas of agricultural soils around the world are contaminated by Cd, a cost-effective and practical method is needed for the safe production of edible plants. The effective role of many nanomaterials to improve plant yield by mitigating environmental pollutions is addressed; however, the impacts of selenium nanoparticles (Se-NPs) have not been well-known yet. The aim of this work was to investigate foliar application of Se-NPs on yield, water content, proline concentration, phenolic content, lipid peroxidation, and essential oil (EO) attributes of coriander (Coriandrum sativum L.) under Cd stress. The plants were exposed to Cd contamination (0, 4, and 8 mg L-1) and foliar application of Se-NPs (0, 20, 40, and 60 mg L-1). The results showed increased Cd accumulation in roots and shoots of coriander plants upon Cd stress; however, Se-NPs alleviated the uptake of Cd. Cd toxicity, particularly 8 mg L-1, decreased shoot and root weight, chlorophyll (Chl), and relative water content (RWC), while Se-NPs improved these attributes. The Cd concentration at 4 mg L-1 and Se-NPs at 40 or 60 mg L-1 increased phenolic and flavonoid contents as well as EO yield. Proline concentration and malondialdehyde (MDA) increased by enhancing Cd stress, but Se-NPs decreased MDA. The GC/MS analysis showed that the main EO constitutes were n-decanal (18.80-29.70%), 2E-dodecanal (14.23-19.87%), 2E-decanal (12.60-19.40%), and n-nonane (7.23-12.87%), representing different amounts under Cd pollution and Se-NPs. To sum up, Se-NPs at 40-60 mg L-1 are effective in alleviating Cd stress.

Foliar-applied silicon nanoparticles mitigate cadmium stress through physio-chemical changes to improve growth, antioxidant capacity, and essential oil profile of summer savory (Satureja hortensis L.).

The use of nanofertilizers is a promising method for enhancing plant productivity and mitigating environmental pollution. The aim of this study was to show the silicon nanoparticles (Si-NPs) effects on growth, water content, phenolic and flavonoid content, and essential oil (EO) profile in aerial parts of summer savory (Satureja hortensis L.) in cadmium (Cd)-contaminated soil. The pot experiment was conducted with Cd concentration (0, 10, and 20 mg Cd kg-1 soil) and foliar application of Si-NPs (0, 0.75, 1.5 and 2.25 mM of SiO2). The results revealed severe Cd stress (20 mg Cd kg-1 soil) significantly decreased root and shoot weight, relative water content (RWC) but increased Cd accumulation in roots and shoots and proline concentration. Moderate Cd level (10 mg Cd kg-1 soil) improved total phenolic content (TPC), total flavonoid content (TFC), and EO content. Under Cd stress, the 1.5 or 2.25 mM Si-NPs were highly effective concentrations to improve the growth and EO yield. The main EO constitutes were carvacrol (43.12-57.6%), γ-terpinene (20.56-25.6%), p-cymene (5.53-11.3%), and thymol (1.65-8.2%) with changes in their concentrations under Cd and Si-NPs. Heat map analysis (HMA) showed fresh weight, dry weight, and EO yield with a higher variation during these treatments had the most significant impact on distinguishing the clusters. The present study recommended 1.5-2.25 mM Si-NPs in improving the physio-biochemical status of summer savory plants to cope with Cd stress.

Carbon nanotube/layered double hydroxide nanocomposite as a fibre coating for determination the essential oils of Achillea eriophora DC with the headspace solid-phase microextraction.

The present study was conducted to synthesise a carbon nanotube/layered double hydroxide nanocomposite by an in situ growth route via electrostatic force. The fabricated carbon nanotube/layered double hydroxide nanocomposite was successful in deposition on a stainless-steel wire for the preparation of the solid-phase microextraction fibre. The produced fibers are enduring with high suitability being chemically and thermally stable capable of coupling to GC and GC/MS. The important extraction parameters including extraction temperature, extraction time, sample mass and added water were simultaneously optimised using an optimisation approach. I comparison to hydrodistillation (HD), headspace single drop micro-extraction) HS-SPME (is advantageous regarding little sample level, time-efficiency, convenience and low cost.

Determination of essential oils composition of blanket-leaf (Stachys byzantina C. Koch.) by microwave assisted extraction coupled to headspace single-drop microextraction.

The composition of essential oils from Stachys byzantina was studied by simple method based on gas chromatography-mass spectrophotometry (GC-MS) following microwave assisted headspace single-drop microextraction (MA-HS-SDME) method. Several parameters affecting MA-HS-SDME such as sample mass, solvent volume, extraction time, microwave power and the nature of extracting solvent were optimised. The MA-HS-SDME method was compared with traditional hydrodistillation (HD) method. Within the study elaborated, thirty-eight components were extracted and identified. Compared with HD, MA-HS-SDME is an easy, rapid and efficient method for the analysis of essential oils in S. byzantina.

Fast analysis of volatile compounds from Lippia citriodora with nanoporous aluminum wire as solid-phase microextraction fibres.

In this study, the efficiency of nanoporous aluminium wires as fibres for headspace solid-phase microextraction (HS-SPME) of volatile compounds from Lippia citriodora was investigated and compared with two anodised methods. The prepared fibres are durable with very good chemical and thermal stability which can be coupled to GC and GC/MS. A one at-a-time optimisation strategy was applied for optimising the important extraction parameters such as extraction temperature, extraction time, sample mass and added water. Compared with hydrodistillation (HD), HS-SPME provide the advantages of a small amount of sample, time-saving, simplicity and cheapness.