Phenolic compounds are plant-derived antioxidants crucial for human health and food preservation. Their bioactive potential including anti-inflammatory, antimicrobial, and anti-carcinogenic properties makes them a vital focus in nutritional, pharmaceutical, and agricultural research. This review critically evaluates the methodologies for their extraction, detection, and quantification to accurately assess antioxidant activity. Oxidative stress in biological systems and food matrices necessitates accurate analytical methodologies for assessing antioxidant behavior, which include both in vitro, in vivo and ex vivo approaches. Sample pretreatment and extraction techniques are critical for reliable analysis and vary depending on the matrix, compound polarity, and target phenolic subclass. We compare conventional extraction techniques (Soxhlet, maceration) with advanced methods like ultrasound-assisted, microwave-assisted, and supercritical fluid extraction. Detection methods reviewed include spectrophotometric assays (e.g., DPPH, FRAP, ORAC), electrochemical sensors, and chromatographic techniques (e.g., HPLC, HPLC−MS). While each method has distinct advantages, a lack of standardization remains the primary challenge, driven by variations in protocols and the vast chemical diversity of phenolics. This review underscores the critical need for integrated, standardized approaches to ensure the accurate and comparable evaluation of antioxidant activity in research and industry.

Fresh fruit and vegetable juices are commonly consumed as a valuable source of nutrients, while wheatgrass juice is, due to its nutritional value, used as a natural dietary supplement. The main aim of this research was to evaluate the effect of wheatgrass juice addition to apple, beet, carrot, orange, and lemon juice on total and in vitro bioaccessible concentrations of K, Ca, Mg, Mn, Fe, and Zn, vitamin C concentration, total phenolic and flavonoid content, and antioxidant activity. In comparison to other juices, wheatgrass juice had the highest total and in vitro bioaccessible concentrations of Ca, Mg, Mn, Fe, and Zn, while beet juice had the highest K concentration. Lemon and orange juices had the highest vitamin C concentration, while the highest total phenolic and flavonoid content were found in wheatgrass juice. After the addition of wheatgrass juice, Ca, Mg, Mn, and Zn concentration increased in all examined juices, vitamin C concentration increased in apple, beet, and carrot juice, total phenolic content increased in carrot juice, while total flavonoid content increased in apple, carrot, and orange juice. In comparison to the examined juices, wheatgrass juice has better nutritional value, and it could be used in a mixture with other juices to improve their nutritional value.

Phenolic compounds represent a broad and structurally diverse class of plant secondary metabolites with importance for both plant biology and human health. This review provides a comprehensive overview of their biosynthesis, chemical diversity, multifaceted functions in plants, roles in the wider ecosystem, and significance in human nutrition and biotechnology. Primarily synthesized via the phenylpropanoid pathway, these compounds encompass major classes such as lignin, flavonoids, and tannins. Within the plant, they perform critical functions including providing structural support (lignin), defending against biotic stresses (e.g., pathogens, herbivores), mediating ecological interactions (pollination, symbiosis, allelopathy), and protecting against abiotic stresses like UV radiation and oxidative damage. Phenolic compounds extend their influence beyond the plant itself by shaping soil ecosystems through rhizodeposition, where they interact with microbial communities and nutrient cycles. At the same time, they play a central role in the health benefits of plant-rich diets, with strong epidemiological evidence linking their regular consumption to a reduced risk of chronic diseases such as cardiovascular disease, cancer, and obesity. The review further examines the significant variation of phenolic content in different food sources and explores the impact of processing methods, highlighting germination as a key strategy for enhancing the nutritional and bioactive value of cereals and legumes. Finally, the potential of phenolic compounds as a source for modern drugs and their targeted production through biotechnological approaches are discussed, underscoring their position as a cornerstone of phytochemical research with ongoing and future applications in health, agriculture, and industry. This paper employs a semi-systematic (or narrative) literature review methodology. A strategic search of key academic databases, including PubMed, Scopus, Web of Science, Google Scholar, was conducted to identify relevant literature and highly influential works. This review aims to synthesize the existing knowledge on phenolic compounds and to emphasize their undeniable impact on human health through an interdisciplinary approach.

Due to the increasing presence of industrial hemp (Cannabis sativa L.) and its multiple possibilities of use, the influence of different light and several biopreparations based on beneficial fungi and bacteria on hemp’s morphological and physiological properties were examined. Different biopreparations and their combinations were inoculated on hemp seed and/or substrate and grown under blue and white light. A completely randomized block design was conducted in four replications within 30 days. For biopreparation treatment, vesicular arbuscular mycorrhiza (VAM) in combination with Azotobacter chroococum and Trichoderma spp. were inoculated only on seed or both on seed and in the substrate. Generally, the highest morphological parameters (stem, root and plant length) were recorded on plants in white light and on treatment with applied Trichoderma spp., both on seed and substrate. Blue light negatively affected biopreparation treatments, resulting in lower values of all morphological parameters compared to control. Leaves pigments were higher under blue light, as compared to the white light. At the same time, 1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), flavonoids, total flavanol content and phenolic acids were not influenced by light type. Biopreparation treatments did not significantly influence the leaves’ pigments content (Chl a, Chl b and Car), nor the phenolic and flavanol content.