Investigation on supercritical CO2 extraction of phenolic-phytochemicals from an epiphytic plant tuber (Myrmecodia pendans)

•Phenolic antioxidants in ant-nest tuber were extracted by co-solvent free SC-CO2.•Density of SC-CO2 is the controlling factor of the extraction yields and compositions.•TPC and TFC correlations by Chrastil and Del Valle–Aguilera density-based models.•High antioxidant capacity of supercritical extract with an IC50 of 3.62 ± 0.12 mg/mL.•SC-CO2 extraction is a viable method to yield purity antioxidant extracts with high purity.

Myrmecodia pendans (ant-nest) is an epiphytic plant with rich content of phytochemicals. In this work, the application of supercritical carbon dioxide (SC-CO2) for extracting several polyphenol and flavonoid compounds from ant-nest tuber include gallic acid, catechin, ferulic acid, caffeic acid, p-coumaric acid, quercetin, luteolin and kaempferol was investigated. Static-analytical extraction experiments were performed at pressures ranged between 9–22.5 MPa and temperatures of 313.15–343.15 K for 6–7 h. Solubility data of total polyphenols (gram gallic acid equivalent (GAE)/L CO2) and total flavonoids (gram quercetin equivalent (QE)/L CO2) were modeled using Chrastil and Del Valle–Aguilera density-based equations. Both equations were able to represent actual solubilities satisfactorily in terms of correlation coefficient and parameter consistency. DPPH-scavenging test showed high antioxidant capacity of supercritical extract with an IC50 level of 3.62 ± 0.12 mg/mL. It was observed a positive linear correlation between bioactive contents of antioxidant extract and the potency of scavenger activity against DPPH free radical.

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