Protocatechuic acid compound and antioxidant activity from Kedondong (Spondias dulcis) leaves extract

Spondias dulcis is a tropical plant that contains phenolic compounds, flavonoids, saponins, alkaloids, and tannins. This study aimed to isolate phenolic compound fromS. dulcis leaves and determine its antioxidant activity. Isolation of phenolic compound was carried out by maceration method using solvents with gradually polarity such as n-hexane, ethyl acetate, and methanol then fractionated by liquid vacuum chromatography and gravity column chromatography. Antioxidant activity of n-hexane, ethyl acetate and methanol fractions of 1750.39±289.91; 26.08±0.35and 50.10±22.13 µg/mL, respectively. The isolate obtained was a yellowish white solid as much as 4.2 mg. The isolatewas characterized using NMR and MS. The results of the analysis with 1H NMR showed that there were 3 proton signals at H 7.43 (1H, dd, J=2; 8 Hz); 6.86 (1H, d, J=8.5 Hz), and 7.48 (1H, d, J=2.5 Hz). Analysis with 13C NMR showed 7 aromatic carbon signals, namely 3 =CH-signals at δc 115.6; 117.8; 123.5 ppm, 3 sp2 quaternary carbon signals at δc 123.1; 145.6; 150.8 ppm, and 1 carbonyl carbon signal at δc 167.5 ppm. Analysis with MS showed that the isolate had a mass m/z=153.02 [M-H]− according to the chemical nomenclatureand molecular formula, C7H6O4was detected asprotocateuric acid compound (3,4-dihydroxy benzoic acid). The antioxidant activity value of it was IC50 20.97±0.98 µg/mL.