Metabolic profiling of different wild and cultivated Allium species based on high-resolution mass spectrometry, high-performance liquid chromatography-photodiode array detector, and color analysis

Garlic bioactive substances and their therapeutic applications for improving human health: a comprehensive review

Garlic (Allium sativum L.) is a widely abundant spice, known for its aroma and pungent flavor. It contains several bioactive compounds and offers a wide range of health benefits to humans, including those pertaining to nutrition, physiology, and medicine. Therefore, garlic is considered as one of the most effective disease-preventive diets. Many in vitro and in vivo studies have reported the sulfur-containing compounds, allicin and ajoene, for their effective anticancer, anti-diabetic, anti-inflammatory, antioxidant, antimicrobial, immune-boosting, and cardioprotective properties. As a rich natural source of bioactive compounds, including polysaccharides, saponins, tannins, linalool, geraniol, phellandrene, β-phellandrene, ajoene, alliin, S-allyl-mercapto cysteine, and β-phellandrene, garlic has many therapeutic applications and may play a role in drug development against various human diseases. In the current review, garlic and its major bioactive components along with their biological function and mechanisms of action for their role in disease prevention and therapy are discussed.

Phenolic Content, Amino Acids, Volatile Compounds, Antioxidant Capacity, and Their Relationship in Wild Garlic (A. ursinum L.)

Allium ursinum L. is a wild relative of garlic, and it is abundant in many antioxidant compounds. Sulfur compounds, primarily cysteine sulfoxides (CSOs), are converted through several reactions into various volatile molecules, which are considered the principal flavor compounds of Alliums. In addition to secondary metabolites, wild garlic is abundant in primary compounds, such as amino acids, which serve not only as building blocks for the health-promoting sulfur compounds but also as antioxidants. The aim of this study was to investigate the link between individual amino acid contents, the total phenolic content, and the profile of volatile compounds as well as their influence on the antioxidant capacity of both the leaves and bulbs of wild garlic populations in Croatia. Both univariate and multivariate methods were used to study the differences in the phytochemical compositions among the wild garlic plant organs and the link between individual compounds and antioxidant capacity. Both the plant organ and location, as well as their interaction, have a significant impact on the content of total phenolic content, amino acids, volatile organic compounds, and the antioxidant capacity of wild garlic.

Effects of Processing on Chemical Composition of Extracts from Sour Cherry Fruits, a Neglected Functional Food

Sour cherries fruits (Prunus cerasus L., syn P. cerasus var. austera) are locally known as "visciola di Sezze", due to the name of the city where they are traditionally cultivated in Lazio Region, Italy. Fruit samples from three harvesting years (June 2019, 2020 and 2021), were submitted to a protocol of analyses to detect the bioactive content based on year of harvest, freezing, homogenization and thermic treatments. Polyphenolic components, particularly anthocyanin compounds, were extracted, purified and analyzed by HPLC-DAD and DI-ESI-MS. An anthocyanin content between 0.24 and 21 mg/g fresh weight and a flavonols content between 0.04 and 0.2 mg/g fresh weight were found, depending on the harvest year and the applied procedures. Anthocyanins, besides being the principal components, were mainly represented by cyanidin-3-glucosyl-rutinoside (about 80%), a not particularly widespread molecule, mostly accounting for polyphenolic content. Color analysis and anti-radical activity of the different obtained extracts were performed with the aim to correlate organoleptic characters and health potential to the detected anthocyanins and flavanols content. Results show that immediate post-harvest freezing is the best way to preserve the bioactive content, the correlated color expression and anti-radical activity.

Characterization and Valorization of 'Sulmona Red Garlic' Peels and Small Bulbs

'Sulmona red garlic' is an Italian variety characterized by a red tunica surrounding a white bulb. Red tunicae and non-commercial small bulbs are food wastes that must be studied for their added value. Hydroalcoholic extracts, obtained by separated inner and outer tunicae and peeled bulbs of small commercial 'Sulmona red garlic' bulbs, harvested at two different years, were first characterized with respect to their color, polyphenolic content, and antiradical activity. Then, an untargeted metabolic profile by means of electrospray ionization Fourier transform ion cyclotron resonance (ESI FT-ICR) mass spectrometry led to a comparative evaluation of the chemical diversity of six different samples. The study was completed by biological tests aiming to evaluate the associated health potential. Data on monocytes/macrophages showed good biocompatibility and a promising cytoprotective effect under oxidative stress conditions of all the extracts. At a molecular level, all the garlic extracts were able to downregulate the hydrogen peroxide-induced cyclooxygenase-2 and inducible nitric oxide synthase expression through the modulation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB) and peroxynitrite intracellular amounts, at different extents depending on the extract, the cell type, and the concentration. On the whole, data highlight an associated health potential of the extracts of this waste plant material both in terms of cytoprotection and of anti-inflammatory activity.

FT-ICR-MS-based metabolomics: A deep dive into plant metabolism

Metabolomics involves the identification and quantification of metabolites to unravel the chemical footprints behind cellular regulatory processes and to decipher metabolic networks, opening new insights to understand the correlation between genes and metabolites. In plants, it is estimated the existence of hundreds of thousands of metabolites and the majority is still unknown. Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) is a powerful analytical technique to tackle such challenges. The resolving power and sensitivity of this ultrahigh mass accuracy mass analyzer is such that a complex mixture, such as plant extracts, can be analyzed and thousands of metabolite signals can be detected simultaneously and distinguished based on the naturally abundant elemental isotopes. In this review, FT-ICR-MS-based plant metabolomics studies are described, emphasizing FT-ICR-MS increasing applications in plant science through targeted and untargeted approaches, allowing for a better understanding of plant development, responses to biotic and abiotic stresses, and the discovery of new natural nutraceutical compounds. Improved metabolite extraction protocols compatible with FT-ICR-MS, metabolite analysis methods and metabolite identification platforms are also explored as well as new in silico approaches. Most recent advances in MS imaging are also discussed.

Protective Effects Induced by a Hydroalcoholic Allium sativum Extract in Isolated Mouse Heart

The aim of the present study was to investigate the possible protective effects of a garlic hydroalcoholic extract on the burden of oxidative stress and inflammation occurring on mouse heart specimens exposed to E. coli lipopolysaccharide (LPS), which is a well-established inflammatory stimulus. Headspace solid-phase microextraction combined with the gas chromatography-mass spectrometry (HS-SPME/GC-MS) technique was applied to determine the volatile fraction of the garlic powder, and the HS-SPME conditions were optimized for each of the most representative classes of compounds. CIEL*a*b* colorimetric analyses were performed on the powder sample at the time of delivery, after four and after eight months of storage at room temperature in the dark, to evaluate the color changing. Freshly prepared hydroalcoholic extract was also evaluated in its color character. Furthermore, the hydroalcoholic extract was analyzed through GC-MS. The extract was found to be able to significantly inhibit LPS-induced prostaglandin (PG) E₂ and 8-iso-PGF_2α levels, as well as mRNA levels of cyclooxygenase (COX)-2, interleukin (IL)-6, and nuclear factor-kB (NF-kB), in heart specimens. Concluding, our findings showed that the garlic hydroalcoholic extract exhibited cardioprotective effects on multiple inflammatory and oxidative stress pathways.

Comparison of the chemical diversity of Vitis rotundifolia and Vitis vinifera cv. ‘Cabernet Sauvignon’

Grapevine is one of the most important fruit plants in the world, mainly due to its grapes and related products, with a highly economic and cultural importance. Every year, vineyards are affected by several pathogen outbreaks and the only way to control them is through preventive applications of agrochemicals every 12 to 15 days. This approach is not sustainable and not always effective. The Vitis genus comprise different species that exhibit varying levels of resistance to pathogens, thus the understanding of the innate resistance/susceptibility mechanisms of these different Vitis species is crucial to cope with these threats. In this work, an untargeted metabolomics approach was followed, using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR-MS), to analyse the metabolic chemical diversity of two Vitis species: Vitis rotundifolia (resistant to pathogens) and V. vinifera cv. ‘Cabernet Sauvignon’ (susceptible to pathogens). Chemical formulas from both Vitis were used to build Van Krevelen diagrams and compositional space plots, which do not require full metabolite identification and provide an easy comparison method. Based only on these visualization tools, it was shown that the V. rotundifolia metabolome is more complex than the metabolome of V. vinifera cv. ‘Cabernet Sauvignon’. Moreover, the regions that present a higher density are associated to lipids, polyketides and carbohydrates. Also, V. rotundifolia metabolome presented a higher ratio O/C compounds.