Ziziphora clinopodioides L. is a valuable medicinal and aromatic plant; however, its special requirements for proper growth and enhanced secondary metabolite composition have limited its production and availability. The lack of appropriate fertilizer dosage recommendations is one of these limiting factors for ex situ conservation and large-scale cultivation. This study investigated the effects of nitrogen (N) fertilization on Z. clinopodioides in both open field and unheated greenhouse conditions. The determined research factor was N dosage (0, 40, 80, and 120 kg N ha⁻¹ in the field) and (0, 200, 400, and 600 mg N pot⁻¹ in the greenhouse). It was found that Z. clinopodioides plants could grow successfully outside their natural habitat with sufficient N fertilization yielding a satisfactory amount of metabolites per plantation area. Specifically, among the tested dosages, the 120 kg N ha⁻¹ (which showed no significant difference from 80 kg N ha⁻¹) and 400 mg N pot⁻¹ fertilizers increased the aboveground dry and fresh biomass, essential oil (EO) content, and yield. Nitrogen fertilization showed a direct correlation with menthone, neo-menthol, menthol, pulegone, E-ocimenone, and spathulenol, but a negative correlation with α-pinene, β-pinene, limonene, 1,8-cineol, trans-pulegol, and iso-menthone. This study is the first to evaluate the effects of N fertilization on the genus Ziziphora. The results indicate that utilizing N fertilizer at a moderate rate (80 kg N ha⁻¹ in the field and 400 mg N pot⁻¹ in the greenhouse) can improve the agronomic traits and EO of Z. clinopodioides.

Capparis spinosa L. (caper) is an important medicinal plant whose bioactive compounds vary significantly depending on its growth stage. This directly affects its pharmaceutical and nutritional value. Collecting C. spinosa at the optimal growth stage is essential to achieving high phytochemical quality and meeting consumer needs. This study aimed to evaluate the variation of these active compounds in the aerial parts of C. spinosa across four phenological stages (vegetative, flowering, unripe fruit, and ripe fruit). The result showed that EO content was highest in unripe fruits (0.18%) and lowest in the flowering stage (0.07%) in leaves, while extract yield was highest in leaves of the ripe fruit stage (14.65%) followed by the flowering stage in flowers (12.66%). Flowering stage leaves showed the highest total phenol (56.20 mg GAE/g) and flavonoid (17.10 mg QE/g) content, while the lowest concentrations were found in the ripe fruit stage of the leaves. EO analysis showed that methyl isothiocyanate reached the highest concentration in flowers at the flowering stage (41.6%), while isopropyl isothiocyanate reached the highest concentration in leaves at the ripe fruit stage (36.2%). Isobutyl isothiocyanate was found exclusively in fruits, with the highest concentration in ripe fruits (9.2%). Dimethyltrisulphide showed a maximum concentration in leaves at the vegetative stage, decreasing by 76.6% as the plant developed towards the ripe fruit stage. The dominant phenolic acids varied between phenological stages: cinnamic acid at the vegetative stage; rosmarinic and cinnamic acids at the flowering stage in leaves; caffeic and cinnamic acids in flowers; vanillic, cinnamic, and rosmarinic acids at the unripe fruit stage in leaves and fruits; and rosmarinic, cinnamic, and vanillic acids in ripe fruits. The results indicate that harvesting C. spinosa at the vegetative stage and in the leaves of the flowering stage is optimal for maximum secondary metabolite yield, providing valuable guidance for growers targeting food and pharmaceutical applications.