Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal; Laboratório Associado para a Sustentabilidade e Tecnologia em Regiões de Montanha (SusTEC), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253 Bragança, Portugal.
Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, 3036 Limassol, Cyprus.
Food Res Int. 2023 Aug;170:113044. doi: 10.1016/j.foodres.2023.113044. Epub 2023 May 23.
The present study aims to determine the combined effect of cropping system and irrigation regime on the chemical composition and bioactive properties of lemon balm aerial parts. For this purpose, lemon balm plants were grown under two farming systems (conventional farming vs organic farming) and two irrigation levels (full irrigation vs deficit irrigation) and harvested twice throughout the growing period. The collected aerial parts were subjected to three different methods of extractions, namely infusion, maceration and ultrasound-assisted extraction and the obtained extracts were evaluated in terms of chemical profile and bioactivities. Five organic acids with varied composition among the tested treatments were identified in all the tested samples for both harvests, namely, citric, malic, oxalic, shikimic and quinic acid. Regarding phenolic compounds composition, the most abundant ones were rosmarinic acid, lithospermic acid A isomer I and hydroxylsalvianolic E, especially for the maceration and infusion extraction methods. Full irrigation resulted in lower EC values than deficit irrigation only in the treatments of the second harvest, while variable cytotoxic and anti-inflammatory effects were recorded in both harvests. Finally, in most cases the lemon balm extracts has similar or better activity than the positive controls, while the antifungal activity of lemon balm extracts was stronger than the antibacterial effects. In conclusion, the results of the present study showed that the implemented agronomic practices, as well as the extraction protocol may significantly affect the chemical profile and bioactivities of lemon balm extracts, suggesting that both the farming system and the irrigation schedule may improve the quality of the extracts depending on the implemented extraction protocol.
本研究旨在确定种植制度和灌溉制度对柠檬香蜂草地上部分化学成分和生物活性的综合影响。为此，采用两种农业系统（常规农业与有机农业）和两种灌溉水平（充分灌溉与亏缺灌溉）种植柠檬香蜂草，并在整个生长期间进行了两次收获。收集的地上部分采用三种不同的提取方法，即浸提、浸提和超声辅助提取，并根据化学成分和生物活性对提取物进行评价。在两次收获的所有测试样品中，均鉴定出 5 种有机酸，其组成在测试处理之间存在差异，分别为柠檬酸、苹果酸、草酸、莽草酸和奎宁酸。在酚类化合物组成方面，迷迭香酸、岩白菜素 A 异构体 I 和羟基萨尔维酸 E 的含量最丰富，特别是在浸提和浸提法中。仅在第二次收获的处理中，充分灌溉的 EC 值低于亏缺灌溉，但在两次收获中均记录到可变的细胞毒性和抗炎作用。最后，在大多数情况下，柠檬香蜂草提取物的活性与阳性对照相似或更好，而柠檬香蜂草提取物的抗真菌活性强于抗菌作用。总之，本研究结果表明，实施的农业措施以及提取方案可能会显著影响柠檬香蜂草提取物的化学成分和生物活性，这表明种植制度和灌溉制度可以根据实施的提取方案来提高提取物的质量。
