Antioxidant Activity of Waterleaf (Talinum triangulare (Jacq.) Willd) Cultivated with Organic Fertilizers during the Rainy Season

Abstract

Talinum triangulare (Jacq.) Willd, known as ginseng Jawa or kolesom Jawa in Indonesia, is one of tropical plants that has been widely used as traditional herbal medicine and consumed as vegetable in Indonesia. The leaf from the plant contains bioactive compound identified as flavonoid which can function as antioxidant. The objective of this research was to measure the antioxidant activity and total phenolic compound of waterleaf in five different treatments of organic fertilization. Extraction of the leaf was carried out with the method of ultrasound assisted extraction/UAE (sample:MeOH=1:10 b/v, t=20 minutes, cold extraction room temperature). The present research resulted that the different organic fertilizer treatments significantly influenced the secondary metabolites content e.g. phenolic content of Talinum triangulare (Jacq.) Willd (p<0.05). High total phenolic content did not always exhibit high antioxidant activity as the highest total phenolic content group (PK+RP: 10.76 mg GAE/g dry sample) had weaker antioxidant activity (DPPH: 1.73 ± 0.01 mg AEAC/g GAE) than thus lower in phenolic content. Organic fertilizer RP+AS (rock phosphate and husk ash) treatment (7.36 ± 0.00 g GAE/g dry sample) exhibited the highest antioxidant activity in scavenging DPPH free radicals and strongest reducing power among all groups (2.06 ± 0.01 mg AEAC/g GAE; 0.022 ± 0.000 mg AEAC/g GAE respectively). Organic fertilizer influenced the secondary metabolite produced by the waterleaf