In phytotherapy, Crataegus (hawthorn) is one of the most remarkable medicinal plants. Recently, it has gained attention for treating diseases mostly affecting the cardiovascular system. The pharmacologically active metabolites that give Crataegus its activity are flavonoids, specifically hyperoside, vitexin, and rutin, according to reports. Consequently, the amounts of these active metabolites in phytopharmaceuticals meant to be made from Crataegus species are standardized in accordance with those specified by the official pharmacopeias. Scientific databases were the source of the knowledge about hawthorn that was available. The information gathered is summarized in this publication together with information on traditional applications, phytochemistry, pharmacology, and concerns. As indicated by the literature review, Crataegus is a polyphyletic genus comprising approximately 3300 species, as demonstrated by phylogenetic and morphological studies. A total of 249 phytochemical compounds have been identified within this genus. These include flavonoids, lignans, fatty acids, organic acids, monoterpenoids, sesquiterpenoids, terpenoids, and steroids, all of which are present in hawthorn. Correlative research on its pharmacological properties and traditional applications is currently lacking. Furthermore, several varieties of hawthorn with traditional uses have not yet been the subject of phytochemical and pharmacological investigation. Consequently, a thorough investigation of the genus Crataegus is essential.

Background/Objectives: Plant-derived diuretics are attracting increasing interest due to their promising efficacy and improved safety profile compared with synthetic drugs. This study aimed to characterize the phytochemical composition of Astragalus boeticus (A. boeticus) extracts, evaluate their diuretic activity, and assess the oral safety of their main phenolic compound. Methods: Aqueous (AQE) and hydroethanolic (EtOHE) extracts were analyzed using LC–MS/MS, while in silico toxicity prediction of trans-resveratrol was performed using ProTox-II and ADMETlab 2.0. Diuretic activity was evaluated in male Wistar rats (n = 24) divided into four groups: control (distilled water, 10 mL/kg), furosemide (10 mg/kg), AQE (300 mg/kg), and EtOHE (300 mg/kg). Urine and plasma samples were collected after 15 days to determine electrolyte concentrations, creatinine level, creatinine clearance, and hepatic enzyme profile. Results: LC–MS/MS profiling identified fourteen phenolic compounds, with trans-resveratrol (270 µg/g in AQE) being the most abundant, followed by cyanidin-3-O-glucoside and gentisic acid. In silico assessments revealed no hepatotoxic, mutagenic, or neurotoxic effects of trans-resveratrol. Both extracts significantly enhanced urinary output, chloride excretion, and creatinine clearance, while maintaining stable renal and hepatic biochemical parameters, indicating potent diuretic activity without toxicity. Conclusions: A. boeticus extracts demonstrate strong diuretic potential associated with a favorable safety profile, likely linked to their phenolic composition dominated by trans-resveratrol. These findings support the use of A. boeticus as a natural and safe diuretic source. Further investigation is recommended to elucidate its pharmacological mechanisms and therapeutic relevance.