Phytochemical Characterization, Hypoglycemic Effect, and Preliminary Toxicological Evaluation of Methanolic and Aqueous Bark Extracts of Lavandula stoechas L.

Abstract

Background: Diabetes mellitus involves chronic hyperglycaemia; plants rich in phenolics, flavonoids, tannins, and terpenoids are explored for glucose-lowering potential. Lavandula stoechas (Ustukhuddus) contains diverse bioactives.

Objective: To prepare methanolic (LSME) and aqueous (LSAE) bark extracts, assess phytochemical profiles, glucose-lowering activity, and preliminary oral toxicity.

Methods: Bark powder was defatted and extracted with methanol/water. Extractive yields and phytochemicals were identified. Acute toxicity was tested in mice (500–2000 mg/kg). A 14‑day study compared control vs. LSME (200, 400 mg/kg) and LSAE (250, 500 mg/kg). Biochemical and haematological parameters were measured.

Results: Yields: LSME 8.3%, LSAE 11.1%. LSME contained alkaloids, saponins, steroids, phenolics, tannins, flavonoids, terpenoids, glycosides, proteins, carbohydrates; LSAE had saponins, phenolics, tannins, flavonoids, terpenoids, proteins, carbohydrates. Acute toxicity showed dose‑dependent behavioural toxicity and mortality (especially LSME). In the 14‑day study, no mortality occurred. Serum glucose fell significantly (control 91.58 mg/dL → 60.30, 47.18, 48.28, 25.66 mg/dL in treated groups). Hepatic enzymes decreased at higher doses; protein, albumin, haemoglobin remained stable.

Conclusion: Both extracts showed strong glucose‑lowering activity, likely due to phenolics, flavonoids, tannins, saponins, and terpenoids. However, acute toxicity indicates a narrow safety margin. Further studies in diabetic models with OECD‑compliant toxicology and mechanistic evaluation are needed before therapeutic application.