First comprehensive compositional analysis of E. arborescens leaves with new insights into their potential as enzyme...

This work aims to determine the chemical composition of E. arborescens leaves for the first time, screening and quantifying various phytochemical compounds. The chemical composition revealed high levels of valuable nutrients, mainly ash (19.32%), which increases its nutritional value and offers health benefits. The phytochemical screening identified numerous secondary metabolites, including phenolic compounds, phytosterols, and flavonoids. Quantification of photosynthetic pigments showed that chlorophyll a is dominant in the leaves. In addition, the methanolic extract of the leaves has inhibitory activity against gram-positive and gram-negative bacteria. The methanolic leaf extract showed an IC₅₀ of 0.04 mg/mL and an EC_0.5 of 0.06 mg/mL for antioxidant activity as assessed by DPPH scavenging assay and iron reducing power respectively. The methanolic extract showed significantly higher reducing power than the aqueous extract. Both methanolic and aqueous leaf extracts exhibited α-amylase inhibitory activity in a dose-dependent manner with statistically significant differences in their IC₅₀ values. Furthermore, the methanolic extract was as effective as acarbose in inhibiting porcine α-amylase with an IC₅₀ of 0.06 mg/mL. It also showed dose-dependent inhibition of pancreatic lipase, with an IC₅₀ of 0.92 mg/mL. Although the IC₅₀ values were not statistically different, both aqueous and methanolic extracts also contained protease inhibitors. Therefore, these results suggest that E. arborescens leaf extracts may be useful for future drug applications, and further research is needed to investigate the mechanisms of enzyme inhibition.