The present work was designed to study the chemical composition and the antioxidant and antimicrobial properties of fruits (SFr) and leaf (SF) extracts from Solanum elaeagnifolium var. obtusifolium (Dunal) Dunal (S. elaeagnifolium). The chemical composition was determined using HPLC-DAD analysis. Colorimetric methods were used to determine polyphenols and flavonoids. Antioxidant capacity was assessed with DPPH, TAC, and FRAP assays. Antimicrobial activity was assessed using disk diffusion and microdilution assays against two Gram (+) bacteria (Staphylococcus aureus ATCC-6633 and Bacillus subtilis DSM-6333) and two Gram (-) bacteria (Escherichia coli K-12 and Proteus mirabilis ATCC-29906), while the antifungal effect was tested vs. Candida albicans ATCC-1023. By use of in silico studies, the antioxidant and antimicrobial properties of the studied extracts were also investigated. HPLC analysis showed that both fruits and leaf extracts from S. elaeagnifolium were rich in luteolin, quercetin, gallic acid, and naringenin. Both SFr and SF generated good antioxidant activity, with IC₅₀ values of 35.15 ± 6.09 μg/mL and 132.46 ± 11.73 μg/mL, respectively. The EC₅₀ of SFr and SF was 35.15 ± 6.09 μg/mL and 132.46 ± 11.73 μg/mL, respectively. SFr and SF also showed a good total antioxidant capacity of 939.66 ± 5.01 μg AAE/and 890.1 ± 7.76 μg AAE/g, respectively. SFr had important antibacterial activity vs. all tested strains—most notably B. subtilis DSM-6333 and E. coli, with MICs values of 2.5 ± 0.00 mg/mL and 2.50 ± 0.00 mg/mL, respectively. SFr demonstrated potent antifungal activity against C. albicans, with an inhibition diameter of 9.00 ± 0.50 mm and an MIC of 0.31 ± 0.00 mg/mL. The in silico approach showed that all compounds detected in SFr and SF had high activity (between −5.368 and 8.416 kcal/mol) against the receptors studied, including NADPH oxidase, human acetylcholinesterase, and beta-ketoacyl-[acyl carrier protein] synthase.

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.