Heavy metal content, phytochemicals quantification, and antioxidant activity of Terminalia ivorensis A. Chev (Combretaceae) leaves collected from Lagos, Nigeria

Investigating heavy metals in medicinal plants like Terminalia ivorensis is crucial for safety, as they can accumulate harmful metals from the environment. Used in traditional West African medicine for various ailments, T. ivorensis has shown important pharmacological activities. However, studies on heavy metal content and specific phytochemicals quantification in its leaves are limited. This investigation aims to address these gaps and further explore its antioxidant activity. T. ivorensis leaves were collected, extracted with 50% ethanol, and analysed for phytochemicals, antioxidants, and heavy metals using standard spectrophotometric, gravimetric, and chemical methods for qualitative and quantitative assessments. Qualitative screening revealed the presence of saponins, phenolics, tannins, flavonoids, cardiac glycosides, terpenoids, steroids, and alkaloids, with no anthraquinones or triterpenoids detected. Quantitative results (mg/100g) showed: alkaloids (32.45 ± 0.343), saponins (30.07 ± 0.015), tannins (36.76 ± 0.107), cardiac glycosides (22.48 ± 0.057), steroids (30.70 ± 0.072), terpenoids (48.60 ± 0.228) and reducing sugars (25.87 ± 0.335 mg GE/100g). High levels of phenolics (220.89 mg GAE/g) and flavonoids (441.63 mg RE/g) were recorded. Antioxidant activity was significant, with DPPH IC50 at 26.54 μg/mL, phosphomolybdate assay at 44.68 ± 0.98 mg AAE/g, and FRAP IC50 at 44.19 μg/mL. Heavy metal analysis detected cadmium (Cd), lead (Pb), calcium (Ca), Zinc (Zn), magnesium (Mg), iron (Fe), Copper (Cu), sodium (Na), potassium (K), and manganese (Mn), all below WHO safety limits.