Regional variation of anti-diabetic and anti-inflammatory activities of Eucalyptus Sideroxylon

Abstract

Medicinal plants serve as a natural reservoir of bioactive compounds with diverse therapeutic properties. This study aimed to evaluate the biological activities—specifically the antidiabetic and anti-inflammatory effects—of leaf extracts from Eucalyptus sideroxylon collected from various regions. Extraction yields varied significantly, ranging from 2.93% to 39.61% depending on the region. Qualitative phytochemical screening revealed the presence of flavonoids, tannins, saponins, coumarins, free quinones, and cardiac glycosides, while alkaloids, sugars, and proteins were consistently absent across all samples. These findings were supported by quantitative analyses of phenolic compounds, tannins, and flavonoids. The red-flowered of E. sideroxylon from the Blida region exhibited the highest total polyphenol content (528.48 mg GAE/g DW) in the methanolic extract, whereas the lowest was recorded in the ethanolic extract from MédéaZerouek pink flowers (42.93 mg GAE/g DW). In terms of tannin content, the aqueous extract from Bouguezoul showed the highest level (832.22 mg EAT/g DW), while the ethanolic extract from Blida had the lowest (83.9 mg EAT/g DW). Flavonoid content was highest in the ethanolic extract of E. sideroxylon from Médéa-Zerouek (103.42 mg RE/g), and lowest in the aqueous extracts (28.34 mg RE/g). Anti-diabetic activity, assessed via α-amylase inhibition, revealed that ethanolic extracts demonstrated the strongest inhibitory effects, particularly those from the pink- and whiteflowered specimens from Médéa. For anti-inflammatory activity, all extracts—including the reference drug diclofenac—showed dose-dependent increases in erythrocyte membrane stabilization. Among them, the methanolic extract emerged as the most effective and consistent