Total flavonoid content and antioxidant activity by different drying and extraction methods of Clinacanthus nutans leaves

This report presents a study on the total flavonoid content and antioxidant activity of Clinacanthus nutans leaves from different drying and extraction methods. The C. nutans leaves were subjected through three different drying methods: oven (40°C, 60°C and 80°C), vacuum oven and air drying. Afterwards, extraction on the dried leaves was performed using three different extraction techniques: Soxhlet, maceration and ultrasound assisted solvent extraction. Finally, total flavonoid and antioxidant activity was determined spectrophotometrically by aluminium chloride colorimetric assay and 2-Diphenyl-1-picryl hydrazyl (DPPH) method respectively. The results showed that the choice of drying and extraction methods had a significant influence on total flavonoid and antioxidant content of C. nutans extract. The combination of drying C. nutans leaves using laboratory oven at 60°C and Soxhlet extraction obtained the highest amount of total flavonoid and antioxidant content at 24.53 ± 0.95 mg RU/g and 89.73 ± 4.39mg TE/ g respectively. The highest antioxidant activity for C. nutansfromair-dried samples and vacuum oven-dried samples were obtained through maceration extraction at 85.46 mg TE/ g and 83.96 mg TE/ g respectively