Selective Preparation Of Capsaicinoids And Ginkgolic Acids By Dummy Molecularly Imprinting Technique

Capsaicinoids are the main active ingredient of Chili peppers(Capsicum annuum L.). They have been widely used in food and clinical medicine. However, using conventional techniques to produce capsaicinoids is energy intensive and time-consuming. Ginkgolic acids(GAs) have two sides of biological activities with medical properties and toxic effects. However, GAs are always excessive levels and they can not be enriched during the traditional processing of Ginkgo biloba leaves It is enormous waste of resources.So how to obtain Capsaicinoids, simultaneously remove and enrich GAs from Ginkgo biloba L. leaves extracts is a valuable and interesting strategy.Molecularly imprinted polymers(MIPs) exhibit many outstanding advantages including high selectivity, chemical and physical robustness, and ease and low cost of preparation. Due to their outstanding advantages, MIPs have great application prospect on natural products preparation and separation. However, it is not desirable to use the target compound as the template due to their high price. What’s more,MIPs using the target compound as the template have specific adsorption for only one target compound, not for a group of homologue compounds. In this study, we find or design structural analogues of the target molecules according to the structure of Capsaicinoids and GAs, as a ‘dummy’ template to prepare DMIPs. Then DMIPs applied as selective adsorption materials to prepare Capsaicinoids, remove and enrich GAs simultaneously. 1. Molecularly imprinted polymers with synthetic dummy templates for preparation of capsaicin and dihydrocapsaicin from chili peppersDMIPs were successfully designed using VNM for the dummy template, selecting the best functional monomer for polymer preparation. The results of 1H NMR analysis indicate that the N–H proton of the VNM and 4-VP partake in the hydrogen bonding present. The adsorption results for the DMIPs show that the maximum adsorption capacity is 21.9 mg g–1 and that adsorption equilibrium was reached after just 20 min. The selective recovery of capsaicinoids was calculated to be 77.8% using dummy molecularly imprinted solid-phase extraction(DMISPE). Because of their simultaneous possession of high affinity, capacity, selectivity, and specificity, DMIPs could be used as adsorbent phase in SPE to enrich CAPS and DHC from chili peppers. 2. Molecularly imprinted polymers with synthetic dummy template for simultaneously removal and enrichment of ginkgolic acids from Ginkgo biloba L. leaves extractsTwo dummy template molecule with similar structural skeleton to GAs, 6-methoxysalicylic acid(MOSA, DT-1) and 6-hexadecyloxysalicylic acid(HOSA, DT-2),have been designed and synthesized,for preparing the dummy molecularly imprinted polymers(DMIPs). The DMIPs sorbents have high specificity for ginkgolic acids(GAs). The results of Brunauer-Emmett-Teller(BET) indicated that the longer alkoxy chains of HOSA could increase the pore volumes of DMIPs. The results of adsorption performance of the DMIPs indicated that DMIPs prepared using HOSA as the dummy template could be used as an adsorbent phase for SPE to remove and enrich GAs from Ginkgo biloba L. leaves extracts. The method showed excellent recoveries(82.5-88.7%) and precision(RSD 0.5-2.6%, n = 5) spiked at three concentration levels each(50, 100, 200 μg mL-1). The results indicated that GAs and standardized Ginkgo biloba leaves extracts could been obtained simultaneously through the DMISPE.