Isolation of aristolochic acid I from herbal plant using molecular imprinted polymer composited ionic liquid‐based zeolitic imidazolate framework‐67

Abstract

Aristolochic acid I is a toxic compound found in the genus of Aristolochia plants, which are commonly used as herbal cough treatment medicines. To remove the aristolochic acid I in extract efficiently and selectively, a molecularly imprinted polymer composed of ethylimidazole ionic liquid‐based zeolitic imidazolate framework‐67 was synthesized and used as the adsorbent. Under the conditions optimized by the software design expert, the sorbent showed highest adsorption amount of 34.25 mg/g in methanol/water (95:5, v/v) at 39°C for 138 min. The sorbent was then applied to solid phase extraction to isolate aristolochic acid I from the extract of the herbal plant Fibraurea Recisa Pierre. 0.043 mg/g of aristolochic acid I was obtained after the loading, washing, and elution processes. The limit of detection of 2.41 × 10−5 mg/mL and good recoveries provided evidence for the accuracy of this method.

Zeolitic imidazolate frameworks in analytical sample preparation

“…The feasibility of using ZIFs as cores for MIPs was explored using ZIF‐67 [51]. The ZIF‐67 crystal surface was modified with vinyl groups and a MIP shell was in situ synthesized enabling the selective extraction of aristolochic acid I from herbal plants.…”

Role of Ionic Liquids in Composites in Analytical Sample Preparation

“…The properties associated to ILs make these materials highly desirable to perform post-synthesis modification of MOFs to increase the interactions between the sorbent and the guest molecules and even to improve stability in several cases [76,77,101,[170][171][172][173]. The combination of ILs and MOFs can be done by physical interactions or by chemical bonding, depending on the preparation procedure.…”

“…Regarding the immobilization of ILs by chemical bonds, it can be carried out by several approaches to form stable bonds between the MOF and the IL. The encapsulation of ILs in MOF is the main procedure followed for the preparation of MOF-ILs composites as alternative to those based on physical interactions [170][171][172]. In the encapsulation approach, the MOF acts as a host and the IL as a guest.…”

“…The SIB protocol has also been used for the preparation of a MIPIL in combination with the MOF ZIF-67(Co) (Figure 6A), which was packed in a SPE cartridge [171]. In this case, authors demonstrated the presence of the IL in the composite is the main responsible of the extraction of aristolochic acid from herbal plants, while the incorporation of the recognition sites with the molecular imprinting leads to quantitative extractions, as shown in Figure 6B.…”

“…(A) Scanning electron microscopy images of the synthetized MIPIL-ZIF-67(Co), and (B) Comparison study of the relationship between the initial concentration of analytes and the amount adsorbed when using neat ZIF-67(Co) (white), modified IL-ZIF-67(Co) (red), non-imprinted PIL-ZIF-67(Co) (blue), and MIPIL-ZIF-67(Co) (green). Adapted from[171], with permissions of John Wiley and Sons, Ltd., 2019.…”