Phytochemical content and antioxidant activity of Parijoto (Medinilla eximia Blume): influence of plant parts and maturity levels
Abstract
Abstract The fruit of Parijoto (Medinilla eximia) is known for its strong antioxidant activity and diverse bioactive compounds, including tannins, flavonoids, and phenolic acids. However, the phytochemical variations and antioxidant properties associated with different plant parts and fruit maturity stages remain largely unexplored. This study investigated the influence of fruit maturation on the total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of ethanolic extracts from Parijoto fruits and fruit stalks, as well as the antioxidant activity of fractions obtained from the most potential extract. Fresh Parijoto fruits were extracted by maceration, followed by fractionation of the most active extract using Vacuum Liquid Chromatography (VLC) with nine solvent systems. TPC and TFC were determined using the Folin-Ciocalteu and aluminum chloride colorimetric methods, respectively. Antioxidant activity of the extracts was evaluated using DPPH and ABTS assays, whereas fractions were assessed using the DPPH assay only. All experiments were conducted in triplicate and analyzed using one-way and/or two-way ANOVA, followed by Tukey's post hoc test. The results revealed that both plant part and maturity stage significantly influenced phenolic and flavonoid accumulation. The highest TPC was observed in ripe fruit (RF) extract (141.51 ± 1.05 mg GAE/g DW), whereas the highest TFC was recorded in ripe fruit stalk (RFS) extract (12.54 ± 0.24 mg QE/g DW). All extracts and fractions exhibited strong antioxidant activity (IC50 < 50 µg/mL), except fraction 1, which showed negligible activity (IC50 1455.62 ± 97.30 µg/mL). Among the crude extracts, RF extract exhibited the strongest antioxidant activity (IC50 10.56 ± 0.32 µg/mL), while fraction 6 showed the highest activity overall (IC50 9.45 ± 0.46 µg/mL). Both DPPH and ABTS assays demonstrated a consistent pattern, with fruit extracts exhibiting significantly stronger antioxidant activity than fruit stalk extracts.