Solvents, Extraction Method and Plant Parts Influence on Phenolic Compound Extracts and Antioxidant Activity of Zanthoxylum zanthoxyloides (Rutaceae)

Background: The study evaluated total polyphenols, total flavonoids, condensed tannins, and antioxidant activity of Zanthoxylum zanthoxyloides plant parts’ extracts. Specifically, the extraction method and solvent influences on the amount of bioactive compound extracted were assessed. Materials and methods: In detail, the extraction methods were the decoction (Dec) and the maceration (Mac). Also, 3 solvents were used, whose were distilled water (Dw), 70% methanol (70%Met), and 70% ethanol (70%Eth). The leaves (L) and bark (B) were collected in the wild at Yamoussoukro, Côte d'Ivoire. Thereafter, they were dried in the laboratory, ground, and then subjected to either aqueous decoction or hydroalcoholic maceration. Total polyphenols, total flavonoids, and condensed tannins were then measured spectrophotometrically. Additionally, antioxidant activity was assessed using ABTS•⁺ cation. Results: The results revealed significant variation in secondary metabolites’ contents. For example, leaves and bark decoction yielded similar polyphenol values for 108.29±9.94 and 105.35±9.94 mg GAE/kg (p=0.837). When it came to the solvents effect, Dw with the leaves, bark, and 70%Met with the bark formed a similar group with 114.55±6.67 mg GAE/kg. Looking at total flavonoids, leaves decoction led to 2.08±0.11, while the bark maceration with 70%Met gave 2.27±0.10 mg QE/kg (p<0.0001). Also, bark decoction and maceration favored condensed tannins extraction for 27.64±5.77 and 22.92±2.58 μg TAE/ kg, respectively (p=0.486). Furthermore, 70%Eth was more effective with 33.37±5.47 μg TAE/kg. Finally, the antioxidant activity was the best with leaves decoction, and 70%Met for 96.02±5.49 and 218.69±5.21 μmol Trolox.E/kg, respectively. Conclusion: Zanthoxylum zanthoxyloides’ leaves are good sources of bioactive compounds.