Safety Concerns of Tectona grandis L.f. Leaf Extract as a Natural Food Colorant: Evidence of Irreversible Organ Pathology in Subchronic Toxicity Study

Abstract

BACKGROUND: Tectona grandis Lf (TG) leaves are traditionally used in Indonesia for natural dyeing, and are gaining popularity as food colorants globally. However, their safety profile remains unclear. Acute toxicity studies reported no fatalities at doses up to 5000 mg/kg BW, histological analyses revealed inflammation and necrosis in the stomach, raising concerns regarding the long-term safety of TG leaf extract. Therefore, this study was performed to evaluate subchronic toxicity of TG leaf extract in both males and females Wistar rats.

METHODS: TG leaf extracts were obtained by water extraction and extract powder was suspended in sodium carboxymethyl cellulose (Na-CMC). Male and female rats were administered TG leaf extract at doses of 0, 10, 20, and 40 mg/kg BW for 28 days, with a 14-days recovery phase in the satellite groups (as controls). Hematology profiles and biochemistry were analyzed using hematology analyzer and spectrophotometry. Histology analysis was performed to investigate TG effects on the organs.

RESULTS: Hematological analysis revealed reversible reductions in hemoglobin, erythrocyte, and hematocrit levels, along with irreversible decreases in leukocyte and thrombocyte. While TG leaf extract did not significantly affect serum glutamic pyruvic transaminase (SGPT), serum glutamic oxaloacetic transaminase (SGOT), or creatinine levels, bilirubin levels increased, but remained within normal ranges. However, histopathological findings at 40 mg/kg BW revealed congestion and inflammation in the digestive organs, as well as neutrophil infiltration and congestion in metabolism-related organs, the lungs, liver, kidneys, and lymph nodes. These pathological changes persisted throughout the recovery period.

CONCLUSION: TG leaf extract raises safety concerns, particularly at a dose of 40 mg/kg BW, as it induces irreversible organ pathology despite reversible changes in blood parameters.

KEYWORDS: Indonesian Tectona grandis Lf, subchronic, toxicity, natural, food, colorants