Determination of aristolochic acid in urine using hollow fiber liquid-phase microextraction combined with high-performance liquid chromatography

On-line enrichment and determination of aristolochic acid in medicinal plants using a MOF-based composite monolith as adsorbent

In this study, modified UiO-66-NH₂ and N-methylolacrylamide (NMA) were used as common monomers to prepare a metal organic framework (MOF)-based composite monolith through in-situ polymerization, which was used as a new adsorbent to purify and enrich aristolochic acid-I (AA-I) in medicinal plants. The MOF-based composite monolithic column was characterized by nitrogen adsorption-desorption isotherm, mercury intrusion porosimetry and scanning electron microscopy (SEM). The adsorption ability of MOF-based composite monolith for AA-I was compared with that of the polymer monolith without MOF added. The results proved that the addition of UiO-66-NH₂ can increase both the specific surface area and the permeability of the monolith. Moreover, the adsorption amount of AA-I on the monolith improved. This proposed on-line solid phase extraction (SPE) method showed good linear relationship in the range 0.044 ~ 400 μg/mL with r = 0.9994; the limit of detection (LOD) was 13.08 ng/mL and the limit of quantification (LOQ) was 44.00 ng/mL; the intra-day and inter-day accuracies were less than 0.97%; the inter-column accuracies was less than 6.11%; the recovery was in the range of 91.11%~106.48%. The method was found to be easy, accurate and convenient for on-line enrichment and purification of AA-I in medicinal plants.

An Overview on Analytical Methods for Quantitative Determination of Aristolochic Acids

Background:

Aristolochic acids are chemically linked to nitrophenanthrene carboxylic acids which are found in aristolochia plants. These compounds are intrinsically carcinogenic, while they have been used in traditional medicine from a long time ago. Despite the beneficial effects of herbals for treating some diseases, they possess some side effects.

Methods:

Therefore, the development of a sensitive and selective procedure for the determination of these harmful components in various complicated samples is an important task for health systems and drug authorities. In the past years, ultra-pressure liquid chromatography, high performance liquid chromatography and capillary electrophoresis with different detection systems were used for determination of aristolochic acids in various samples.

Results:

In this review, different analytical methods have been discussed in brief and applications of them in diverse samples have been summarized.

Conclusion:

Different approaches are compared from point of sensitivity, selectivity, and extraction efficiency.

Three-phase hollow-fiber microextraction combined with ion-pair high-performance liquid chromatography for the simultaneous determination of five components of compound α-ketoacid tablets in human urine

The determination of α-ketoacid concentration is demanded to evaluate the absorption and metabolic behavior of compound α-ketoacid tablets taken by chronic kidney disease patients. To eliminate the interference of endogenous substance of urine and enrich the analytes, a three-phase hollow-fiber liquid-phase microextraction combined with ion-pair high-performance liquid chromatography method was established for the determination of d,l-α-hydroxymethionine calcium, d,l-α-ketoisoleucine calcium, α-ketovaline calcium, α-ketoleucine calcium, and α-ketophenylalanine calcium of compound α-ketoacid tablets in human urine samples. The extraction parameters, such as organic solvent, pH of donor phase and acceptor phase, stirring rate, and extraction time were optimized. Under the optimal conditions, the obtained enrichment factors were up to 11-, 110-, 198-, 202-, and 50-fold, respectively. The calibration curves for these analytes were linear over the range of 0.1-10 mg/L for α-ketovaline calcium, d,l-α-ketoisoleucine calcium, and α-ketoleucine calcium, 0.5-10 mg/L for d,l-α-hydroxymethionine calcium, and α-ketophenylalanine calcium with r > 0.99. The relative standard deviations (n = 5) were less than 6.27% and the LODs were 100.7, 10.0, 5.8, 7.8, and 8.6 μg/L (based on S/N = 3), respectively. Good recoveries from spiked urine samples (92-118%) were obtained. The proposed method demonstrated excellent sample clean-up and analytes enrichment to determine the five components in human urine.

Chinese herbs containing aristolochic acid associated with renal failure and urothelial carcinoma: a review from epidemiologic observations to causal inference

Herbal remedies containing aristolochic acid (AA) have been designated to be a strong carcinogen. This review summarizes major epidemiologic evidence to argue for the causal association between AA exposure and urothelial carcinoma as well as nephropathy. The exposure scenarios include the following: Belgian women taking slimming pills containing single material Guang Fang Ji, consumptions of mixtures of Chinese herbal products in the general population and patients with chronic renal failure in Taiwan, occupational exposure in Chinese herbalists, and food contamination in farming villages in valleys of the Danube River. Such an association is corroborated by detecting specific DNA adducts in the tumor tissue removed from affected patients. Preventive actions of banning such use and education to the healthcare professionals and public are necessary for the safety of herbal remedies.

Use of hollow fiber liquid phase microextraction and HPLC for extraction and determination of apigenin in human urine after consumption of Satureja sahendica Bornm

The applicability of hollow fiber liquid phase microextraction (HF-LPME) was evaluated for extraction and preconcentration of apigenin prior to its determination by HPLC. Different parameters affecting the HF-LPME recovery such as nature of organic solvent, pH of donor and acceptor phases, extraction time, stirring speed, salt addition were optimized. Under optimum conditions (1-octanol as organic solvent, pH of the donor phase=3 and pH of acceptor phase=11.5, extraction time of 75 min, stirring speed of 1000 rpm) limit of detection (LOD) of 0.1 ng/mL, linear range of 0.5-300 ng/mL and correlation of determination (R(2)) of 0.9956 were obtained. The relative intra and inter-day standard deviations (RSD%) based on five replicate measurement were 3.5% and 10.7% respectively. Enrichment factor of 315 and recovery 85% were achieved. Finally, the applicability of the proposed method was evaluated by extraction and determination of apigenin in urine sample after consumption of Satureja sahendica Bornm. which is a native medicinal plant from Iran. Concentration of apigenin in urine sample was found to be 6.20 ng/mL.