The study team evaluated granules formulated from an ethanolic leaf extract of Urtica dioica for oral toxicity in rodents under Indonesian BPOM Regulation No. 10 of 2022. Female Swiss Webster mice received a single oral dose of 5, 50, 500, or 5000 mg/kg to assess acute toxicity. No mortality occurred at the highest tested dose, indicating an LD50 above 5000 mg/kg in this acute setting. For subchronic assessment, Sprague–Dawley rats of both sexes (five animals per sex per group) underwent daily dosing for 13 weeks (90 days) at 77.5, 155, or 310 mg/kg/day. Satellite groups were observed for an additional 30-day recovery period. The report is a preprint and has not been peer reviewed, and the authors declared no competing interests.
The acute mouse cohort showed no dose-related mortality at doses up to 5000 mg/kg. Clinical signs, rectal temperature, and body-weight changes during the single-dose phase did not display clear dose-dependent adverse trends, according to the authors. During the 90-day rat study the investigators did not report treatment-related deaths. The team measured routine clinical observations throughout dosing and recovery; the manuscript did not describe any unexpected clinical syndrome attributable to the granules.
After 90 days of repeated administration, erythrocyte indices and commonly used renal function markers — blood urea nitrogen and creatinine — were unchanged in both male and female rats. Those results suggest the absence of gross hemolytic or renal biochemical toxicity within the measured parameters. The authors reported a statistically significant increase in leukocyte count in high-dose females (p < 0.05). This leukocytosis was not observed in the corresponding high-dose recovery group, indicating the change may have been transient or reversible. Liver weights differed among female groups; however, the pattern did not follow a monotonic dose-response as presented by the study team. The manuscript did not report histopathology detail in the abstract, and it did not provide additional mechanistic investigations into the liver-weight differences in the text available in the source abstract.
Body-weight trajectories during the 90-day exposure varied by sex and dose. The authors observed that weight gain at the highest dose differed from control in both sexes but moved in opposite directions for males and females. The effect did not produce a clear, consistent toxicologic signal tied to dose across sexes. In the recovery phase, the leukocyte elevation seen in high-dose females resolved: the high-dose recovery group did not show the same leukocytosis. The presence of this recovery data provides limited evidence for reversibility of at least some hematologic changes, but the authors did not present further follow-up biomarkers or functional testing within the abstract to fully characterize recovery dynamics.
The authors explicitly noted methodological and baseline issues that limited hazard characterization. Control group values for some endpoints fell outside the expected strain reference range, and there was a pre-existing baseline body-weight imbalance among groups prior to dosing. Because of these problems, the study team was unable to establish a clear no-observed-adverse-effect level (NOAEL) from their dataset. The abstract did not provide protocol-level details that might explain the control variation or imbalance, such as randomization procedures or full baseline tables; those details were not reported in the source abstract.
Limitations spelled out in the report include the absence of a definable NOAEL due to control-range deviations and baseline imbalances, and the manuscript is available only as a preprint pending peer review. The authors did not declare competing interests. Open questions that remain from the available text include whether histopathology or additional biomarkers were performed to explore the liver-weight differences and whether further GLP-compliant studies with corrected baseline balance would reproduce the hematologic signal observed in high-dose females.
The dataset reported limited safety signals: no mortality at an acute oral dose of 5000 mg/kg and largely unchanged erythrocyte and renal biochemical measures after 90 days. Still, the procedural and control-group issues reported by the investigators restrict the strength of toxicologic conclusions. The next steps implied by the manuscript are further controlled repeat-dose studies with clear baseline balance and thorough histopathology to support regulatory safety assessments. The preprint status should be taken into account by readers and regulators seeking definitive safety data for human use.