Geographical variation in total phenolics, flavonoids and antioxidant activities of Eucalyptus camaldulensis leaves in Burkina Faso

Abstract

This study aimed to elucidate the effect of sampling location of Eucalyptus camaldulensis leaves on antioxidant activity, total phenolic content (TPC) and total flavonoid content (TFC). Leaves of E. camaldulensis collected at three different locations in Burkina Faso (north, central, south-west) were subjected to hydrodistillation to obtain a water extract and subsequent ethanol extraction of the solid residue. The extracts were analysed for antioxidant activity using 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging, TPC, TFC and high-performance thin layer chromatography (HPTLC) fingerprint. TPC were higher in water extracts and presented considerable variation from 129±9 to 266±4 milligram Gallic Acid Equivalent per gram of extract (mg GAE/g) with the highest value 266±4 mg GAE/g at the south-west site. This aqueous extract also showed high antioxidant activity with EC50 8.3 µg/mL. Furthermore, HPTLC fingerprint of the extracts showed both band intensity and size differences. For TFC, we found a slight differences within both water and ethanolic extracts with the highest value of 38.3 ±4.2 mg QE/g for the south-west ethanolic extract. The noticeable impact of climate on chemical variability of E. camaldulensis leaves needs to be taken into consideration for any further applications based on TPC biological activity of the extracts. Key words: Eucalyptus camaldulensis, total phenolic content, total flavonoid content, antioxidant activity, sample location, chemical variation.