Deep Eutectic Solvent as Green Alternative Solvents for Polygodial Extraction with Validated HPLC-UV Analysis and Evaluation of their Bioactivities

Introduction

Akway (Tasmannia piperita), a native Papua plant is known for its benefits as stamina enhancer, antimicrobial, and antioxidant agents, which can be associated to polygodial, its marker compound. Green alternative solvents for polygodial extraction are required.

Objectives

In this study, an HPLC-UV method was developed for polygodial analysis from akway barks extracted by deep eutectic solvent.

Materials and Methods

Two types of DES were synthesized and used for extraction of akway barks, i.e. menthol:1-dodecanol (M-1D) (1:2) and Tetrabutylammonium Chloride: 1-Dodecanol (TBAC-1D) (1:2). Yields and antioxidant activities were compared with organic solvent (dichloromethane, ethanol, and hexane) extracts.

Results

An HPLC-UV method was validated and applied for polygodial analysis under the following conditions: gradient mobile phase of acetonitrile-0.07% formic acid at a flow rate of 0.6 mL/min, detection at 230 nm, and separation using a C18 column (150 x 4.6 mm, 5 µm). Solvent polarity influenced polygodial yields, i.e. dichloromethane > hexane > M-1D > TBAC-1D > ethanol. With regards to DES, M-1D and TBAC-1D were able to extract polygodial with yields comparable to hexane. All DES extracts showed low phenolic content, and negligible antioxidant activities by DPPH, ABTS, and FRAP assays compared to organic solvent extracts.

Conclusion

The HPLC-UV method can be applied for analysis of polygodial in akway barks extracted by both organic solvents and DES. This study can recommend M-1D and TBAC-1D for green extraction of polygodial from akway barks.