Comprehensive phytochemical characterization, antioxidant potency, and toxicological evaluation of Paederia foetida in Wistar albino rats: Insights into therapeutic efficacy and safety profiles.

ETHNOPHARMACOLOGICAL RELEVANCE: Paederia foetida has long been utilized in traditional medicine, necessitating comprehensive safety assessments and precise dosage recommendations to avert potential adverse effects in human use.

OBJECTIVE: This study aimed to identify and characterize the key phytocompounds in P. foetida, evaluate their antioxidant and biological activities, and assess their safety through acute and sub-acute toxicity studies in a rat model, thereby establishing a scientific basis linking chemical composition, therapeutic potential, and safety.

MATERIALS AND METHODS: The qualitative profiling, total phenolic, flavonoid content, and antioxidant activity of aqueous (PFAE), ethanol (PFEE), and methanol (PFME) extracts were evaluated using established protocols and the PASS tool employed to predict their therapeutic potential. High-resolution liquid chromatography-mass spectrometry (HR-LC-MS) was employed for the identification and detailed characterization of bioactive constituents in the whole plant methanolic extract (PFME) of P. foetida based on their superior antioxidant activity. Polyphenolic compounds were quantified using high-performance liquid chromatography (HPLC). Acute (control, 500, 1000 and 2000 mg/kg, 14 days) and sub-acute (control, 500, 1000 and 1500 mg/kg, 28 days) toxicity studies were conducted on PFME at the selected doses in male and female Wistar albino rats, incorporating clinical observations, mortality tracking, hematological, biochemical, and histopathological evaluations.

RESULTS: PFME exhibited the highest concentration of total phenols (3761.68 mg GAE/g) and flavonoids (2336.54 mg RuE/g) among the extracts analyzed. HR-LC-MS of PFME identified 36 polyphenolic compounds, with chlorogenic acid (221.84 mg/g), isoquercetin (178.47 mg/g), rutin (169.88 mg/g), scopoletin (148.99 mg/g), quinic acid (111.31 mg/g), and quercetin (71.19 mg/g) being the most abundant. Predictive analysis with the PASS tool revealed strong antioxidant, free radical scavenging, anti-inflammatory, and anti-apoptotic activities of PFME. PFME demonstrated superior antioxidant potency relative to PFEE and PFAE in assays for DPPH, ABTS•+, superoxide radicals, and reducing power. Acute toxicity studies revealed no mortality at any dose level, with no significant alterations in hematological, biochemical, or histopathological profiles, confirming PFME's high safety margin with an LD50 exceeding 2000 mg/kg in both male and female rats. Sub-acute toxicity studies showed no mortality at doses of 500 and 1000 mg/kg, with no significant changes in hematological, biochemical, or histological profiles of lung, brain, kidney, or liver tissues. However, at 1500 mg/kg, significant changes were observed in hematological and serum biochemical profiles, with histopathological abnormalities in liver and kidney tissues of male and female rats. Female rats showed a higher incidence of histological abnormalities.

CONCLUSION: The therapeutic effects of P. foetida are closely linked to its high levels of polyphenols, especially chlorogenic acid, isoquercetin, rutin, scopoletin, quinic acid, and quercetin. These compounds are very important for its strong antioxidant and protective effects. PFME showed superior antioxidant and free radical scavenging activity than the PFEE and PFAE. PFME exhibited a favorable safety profile, with no adverse effects detected at doses up to 2000 mg/kg in acute toxicity studies and 1000 mg/kg/day in sub-acute toxicity studies, thereby establishing this dosage as the No-Observed-Adverse-Effect Level (NOAEL). These findings not only validate the traditional utilization of P. foetida but also establish a scientific foundation for its ongoing research and prospective advancement into safe and efficacious medicinal product formulations.