Zoran Zorić

Essential oils from Mediterranean wild plants are widely used, but the hydrodistillation residues produced in parallel with these essential oils are significantly understudied and underexploited. Since there are only fragmentary data in the literature, we have, for the first time, systematically analyzed the chemical composition of the by-products obtained after hydrodistillation of sage, bay laurel, and rosemary leaves, i.e., hydrolates, water residues, and solid residues. The chemical composition of the hydrolates changed compared to their respective essential oils towards the dominance of more hydrophilic, oxygenated compounds, such as camphor in sage, 1,8-cineole in bay laurel, and berbenone in rosemary. However, some compounds, mostly sesquiterpenes, which were present in considerable amounts in essential oils, were absent or only present in very small amounts in the hydrolates. Furthermore, both the water and the solid residues were rich in polyphenols, such as procyanidins in bay laurel and rosmarinic acid in rosemary and sage. In conclusion, we demonstrate the valuable chemical composition of sage, rosemary, and bay laurel hydrodistillation by-products and discuss a wide range of their possible applications.

Pistacia lentiscus is an evergreen shrub widely used in folk medicine due to the high biological potential of the leaves’ phenolic compounds. Since phenolic compounds are susceptible to degradation under different heat, light and oxygen conditions, various microencapsulation techniques, such as spray drying, can be used to increase their stability. The objective of this study was to examine the influence of different carriers (gum arabic (GA), maltodextrin 13–17 DE (MD), β-cyclodextrin (BCD) and their mixtures), carrier concentrations in feed (12.8, 16 and 19.2% (m/V)) and drying temperatures (120, 150 and 180 °C) on the physiochemical properties, total phenolic content (TPC) and antioxidant activity (AOA) of Pistacia lentiscus leaf extract powders. Product yields of powders ranged from 23.53 to 65.51%, moisture content from 2.89 to 12.03%, hygroscopicity up to 4.45 g/100 g, solubility from 27.11 to 86.84% and bulk density from 0.24 to 0.45 g/mL. All obtained powders had satisfactory physicochemical properties, except BCD powders, which resulted in the lowest product yield, solubility and bulk density. However, BCD powders and those produced with GA containing mixtures retained the highest amounts of TPC and AOA. Thereby, the carrier mixtures with GA at a concentration of 19.2% and dried at 150 °C are recommended as the most suitable for the production of encapsulated Pistacia lentiscus leaf extracts with desirable physicochemical properties, rich in phenolics and with high antioxidant activity.

Allelopathy is a biological phenomenon of synthesizing and excreting compounds that can affect the growth of various organisms, i.e., plant species. The aim of this work was to investigate the possible allelopathic influence of aqueous extracts, obtained from plant species chia (Salvia hispanica L.), black cumin (Nigella sativa L.), wormwood (Artemisia absinthium L.), and nettle (Urtica dioica L.), on the seed germination growth and morphometric characteristics of pepper (Capsicum annuum L.), spinach (Spinacia oleracea L.) and lettuce (Lactuca sativa L.) seedlings in laboratory conditions. Pepper, spinach, and lettuce seedlings were treated with aqueous extracts of chia, nettle, wormwood, and black cumin of different concentrations (2.5, 5 and 10%, respectively). The aqueous extracts were prepared according to the method developed by Norsworthy and the qualitative and quantitative analysis of phenolic compounds in aqueous extracts were performed using ultra-performance liquid chromatography electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS). Phytochemical composition of chia aqueous extracts showed the highest content (above the 1 mg L−1) of epicatechin, quinic acid, caffeic acid, esculetin and cinnamic acid in the comparison with others from the total of 19 detected chemical compounds. In aqueous extracts of black cumin, there were six compounds detected in content above 1 mg L−1, i.e., epicatechin, quinic acid, caffeic acid, esculetin, cinnamic acid, and kaempferol. The same compounds were the most abundant in wormwood extracts, along with gallic acid. Epicatechin and esculetin were only two compounds detected in aqueous extract of nettle in concentration higher than 1 mg L−1. According to the results of this study, only the treatment of spinach seeds with chia aqueous extract in concentration of 2.5% before germination stimulates the germination of spinach seeds, and wormwood herbs and chia extracts in concentrations of 2.5 and 5% stimulate the germination of lettuce seeds and the growth of hypocotyl and radicle length of developed seedlings. The treatment of pepper and lettuce seeds with aqueous extract of nettle in concentration of 10% completely inhibited seed germination.