Insights into the interactions between <i>Deverra tortuosa</i> and <i>Schizomyia buboniae</i> : phytochemicals, antioxidant capacity, and enzyme inhibitory effects

<i>Schizomyia buboniae</i> (Diptera: Cecidomyiidae) induces berry-like galls on the stems of <i>Deverra tortuosa</i> (Desf.) DC. It is also known as "Shabat El-Gabal" and is one of the most important aromatic medicinal plants in Egypt. Many researchers have reported the relationship between galling insects and plant secondary metabolites, but this relationship is not quantitative. This study investigated the impact of <i>S. buboniae</i>-induced galls on physiological traits, phytochemical profiles, antioxidant capacity, and antinutrient levels in <i>D. tortuosa</i> stems. Our results reported that photosynthetic pigment levels, including chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids significantly decreased in galled stems by 63%, 14%, 44%, and 53%, respectively (<i>p</i> < 0.05). Antioxidant enzyme activities such as polyphenol oxidase (PPO), peroxidase (POX), catalase (CAT) and superoxide dismutase (SOD) significantly increased in galled stems by 173%, 88%, 125% and 25%, respectively, indicating elevated oxidative stress response. The analysis of phytochemical compositions revealed that the galled stems of <i>D. tortuosa</i> contained significantly higher levels of total flavonoids, flavonols, saponins, steroids, tannins, alkaloids, cardiac glycosides, and total phenolic compounds compared to non-galled stems, suggesting enhanced production of secondary metabolites. Additionally, galled stems exhibited higher levels of phytates, oxalates, and cyanogenic glycosides than non-galled stems. Proximate contents, including lipids, carbohydrates and proteins, were also elevated in galled stems. Furthermore, galled stems exhibited significantly (<i>p</i> < 0.05) stronger antioxidant activity than non-galled stems. <i>S. buboniae</i> appears to modify the phenotype of <i>D. tortuosa</i>, inducing tissue differentiation and activating defense-related responses. These results reveal that gall composition alters key physiological and biochemical traits in <i>D. tortuosa</i>, possibly as a defense response or as a result of insect interference. The study provides novel insights into the complex plant-insect interaction and highlights the potential implications for the plant medicinal value and suggests that gall-induced tissues of <i>D. tortuosa</i> may be valuable sources of bioactive compounds for pharmaceutical applications.