Antioxidant capacity of Coelogyne pandurata extracts at different phenological phases

ABSTRACT Coelogyne pandurata L., an orchid native to Indonesia, has medicinal properties and potential for lowland cultivation. This study assessed the phenolic and flavonoid contents and antioxidant activity of the leaves, bulbs, and flowers in the vegetative and generative phases of C. pandurata. The total phenolic content (TPC) and total flavonoid content (TFC) were measured using colorimetric methods. The antioxidant activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging and ferric-reducing antioxidant power (FRAP) assays. Plant parts (leaves, bulbs, and flowers) were analyzed across two phenological phases (vegetative and generative) with three replicates for each combination. Each experimental unit comprised five biological replicates. The extracts were prepared via ultrasonic extraction using methanol, ethanol, and n-hexane. The range of TPC was 2.51-11.44 mg gallic acid equivalent per g dry weight (DW), that of TFC was 6.05-38.16 mg quercetin equivalents per g DW, that of the DPPH antioxidant activity was 0.21-1.41 µmol Trolox equivalent (TE) per g DW, and that of the FRAP capacity was 15.63-80.70 µmol TE g−1 DW. Ethanol extracts, particularly from preflowering bulbs, exhibited the highest TPC, TFC, and antioxidant activity, underscoring its superior extraction efficiency for C. pandurata.