Conductive polymer sorbent for extraction and determination of resveratrol and polydatin in Polygonum cuspidatum root samples.

INTRODUCTION: The quantitative analysis of trace resveratrol and polydatin in plant tissues is suitable for elucidation of the compounds' mechanisms of action. OBJECTIVES: The main objective of this work was to develop a feasible and effective sample pretreatment method to measure the concentrations of resveratrol and polydatin in complex samples. METHODOLOGY: A polymer sorbent, poly(2-mercaptobenzimidazole), was electrochemically prepared and utilized for selective extraction, while resveratrol and polydatin were used as target analytes. The sorbent was characterized by cyclic voltammetry, scanning electron microscopy and Fourier transform infrared spectroscopy. After extraction and elution, the analytes were analyzed by a Thermo U3000 HPLC system. Several affecting parameters, including the volume of elution solution, sample pH value, sample flow rate and sample volume, were evaluated and optimized. RESULTS: The proposed method showed good linearity with low limits of detection (from 0.5 to 0.8 ng·mL-1 ) and ideal accuracy with spiked recoveries from 81.30% to 99.16%. A good enrichment factor (more than 200-fold) together with good sensitivity was obtained with this method. Analysis of resveratrol and polydatin in Polygonum cuspidatum samples by this method is efficient. CONCLUSION: The method developed in this work exhibits several significant merits, including easy operation and high extraction efficiency, indicating that electrochemically prepared polymer sorbent is useful for sample pretreatment and analysis of traditional Chinese medicine samples.

[Preparation and in vitro release characteristics of curcumin loaded biodegradable microspheres].

OBJECTIVE: To prepare curcumin-loaded poly-(D,L-lactide-co-glycolide) microspheres and study its release characteristics in vitro. METHOD: Curcumin-loaded poly-(D,L-lactide-co-glycolide) microspheres were prepared by W/O/W emulsification solvent-evaporation process. The microspheres were characterized in terms of morphology, size, encapsulation efficiency, the rate of drug loading and in vitro drug release. RESULT: The formed microspheres were spherical with smooth surfaces. The distribution of particle size was uniform and average size was 1 151 nm. The rate of drug loading was (1.98 +/- 0.14)% and the encapsulation efficiency was (59.44 +/- 4.05)%. In vitro release study revealed that the 71-hour accumulative release percentage reached 77%. CONCLUSION: Curcumin loaded poly-(D,L-lactide-co-glycolide) microspheres are prepared successfully and show good sustained-release characteristics.

Electrochemically deposited conductive composite sorbent for highly efficient online solid-phase microextraction of jasmonates in plant samples.

Conductive composite films composed of poly (3, 4-ethylenedioxythiophene) (PEDOT) and sulfonated graphene were electrochemically deposited on carbon fiber bundle in aqueous solutions for solid phase microextraction (SPME). During the electro-polymerization process, negatively charged sulfonated graphene were doped in PEDOT layer and uniformly dispersed in the composite. The modified carbon fiber bundle worked as sorbent was then successfully applied to online SPME-HPLC-UV analysis of jasmonates in wintersweet flowers. High extraction efficiency (over 420-fold), low limits of detection (0.1ngmL-1 for jasmonic acid and 0.01ngmL-1 for methyl jasmonate) and wide linear ranges (0.5-5000 and 0.05-5000ngmL-1, R>0.9997) have been obtained. It has been demonstrated that this method can be well used for jasmonates analysis in fresh wintersweet flowers with good recoveries (92.4-98.9%). The results were confirmed by HPLC-MS method.