The sustainable management of the environment and crop production in modern agriculture involves dealing with challenges from climate change, environmental pollution, depletion of natural resources, as well as pressure to cope with dependence on agricultural inputs. Balancing crop productivity with environmental sustainability is one of the main challenges for agriculture worldwide. The emergence of weeds resistant to synthetic herbicides generates huge economic losses, so unconventional weed control strategies, especially those based on ecological principles, are very much needed in modern agriculture. Incorporating a natural eco-friendly approach—allelopathy—as a tool in an integrated weed control plan by growing specific crops or spraying fields with extracts containing allelopathic compounds can significantly reduce the use of herbicides. Allelopathy is considered a multi-dimensional phenomenon occurring constantly in natural and anthropogenic ecosystems, by which one organism produces biochemicals that influence the growth, survival, development, and reproduction of other organisms. The objective of this systematic literature review is to present a comprehensive overview of allelopathy, define this phenomenon, and classify allelochemicals. This paper also discusses and highlights recent advances, ongoing research, and prospects on plant allelopathy management practices applied in agriculture, and the underlying allelopathic mechanisms. The review suggested the holistic view of some allelochemicals as an ecological approach to integrated weed control and is an important contribution to future research directions of multidisciplinary programs, chemoinformatic tools, and novel biotechnology methods to plant breeding.

Vitamins are organic compounds that are required for various biological functions. In general, vitamins are not synthesized in the human body, but lack or deficiency of them may lead to certain diseases. Determinations of 11 vitamins in various products were performed, which included ascorbic acid (C), seven vitamins of the B group (thiamine B₁, riboflavin B₂, nicotinamide B₃, pantothenic acid B₅, pyridoxine B₆, folic acid B₉, and cyanocobalamin B₁₂), as well as three fat-soluble vitamins (retinol A, cholecalciferol D₃, and α-tocopherol E). A column with RP18 stationary phase and a diode array detector with properly selected analytical wavelengths for each compound were used. A gradient of trifluoroacetic acid in water with methanol was used as the mobile phase. Limits of quantification in the range of 0.70–2.90 μg/mL for water-soluble vitamins and 1.85–15.84 μg/mL for fat-soluble vitamins were obtained. Those values are sufficient for determinations of the aforementioned compounds in foodstuff. The developed procedure of sample preparation together with chromatographic system can be used for food quality monitoring in the food industry.

Chromatographic system for simultaneous determination of levodopa, biogenic amines, and methylxanthines in food has been developed. Chromatographic column and pre-column with octadecylsilane phase and simultaneously fluorescence and DAD detectors have been used. Gradient elution with acetate buffer (pH = 4.66) with acetonitrile has been applied. Examination included levodopa, norepinephrine, dopamine, normetanephrine, tyramine, and serotonin as well as caffeine, theophylline, and theobromine. Limit of detection (LOD) and limit of quantitation (LOQ) have been determined for all compounds with signal to noise ratio (S/N) equal to 3 and 10, respectively. LOD of 10 ng/mL and LOQ of 30 ng/mL for levodopa and biogenic amines as well as LOD of 70 (60) ng/mL and LOQ of 210 (180) ng/mL for methylxanthines have been determined. Authors have also developed method for simultaneous separation of all analytes from food matrix. Developed chromatographic system with sample preparation method has been applied for determination of examined compounds in cocoa products, vegetables, and fruits.

A chromatographic system is developed for the separation and determination of levodopa, biogenic amines, and their metabolites from the catecholamines group: dopamine (DA), epinephrine (E), normetanephrine (NMN), metanephrine (MN), 3,4- dihydroxyphenylacetic acid (DOMA), 3-metoxy-4-hydroxyphenylglycol (MHPG), and homovanillic acid (HVA); and indoloamines group: serotonin (5HT) and 5-hydroxyindole-3-acetic acid (5HIAA) in urine. The limit of detection (LOD) and limit of quantitation (LOQ) are determined for all compounds with signal-to-noise ratio (S/N) of 3 and 10, respectively. LOD 10 (ng/mL) and LOQ 30 (ng/mL) are determined for L-DOPA, DOMA, E, NMN, DA, MN, and MHPG, as well as LOD 8 (ng/mL) and LOQ 24 (ng/mL) for HVA, 5HT, and 5HIAA. A fluorescence detector is used. Gradient elution with acetate buffer (pH = 4.66) with methanol is applied. In urine samples from patients treated with levodopa, the following concentrations (µg/mL) of analytes are determined: L-DOPA 3.73–46.80, DOMA 1.43–28.43, E 0.83–13.57, NMN 2.58–8.81, DA 24.07–62.11, MN 0.89–66.20, MHPG 6.72–63.64, 5HT 22.96–95.27, 5HIAA 1.45–14.77, and HVA 0.21–15.07.