Removal of tetracycline from water by catalytic photodegradation combined with the microalga Scenedesmus obliquus and the responses of algal photosynthesis and transcription.

The antibiotic tetracycline (TC) and its degradation products (TDPs) in degradation solution present serious environmental problems, such as human health damage and ecological risk; thus further treatment is required before being released into the aquatic environment. Furthermore, their environmental impact on microalgae remains unclear. In this study, TC was degraded by photocatalysis using birnessite and UV irradiation, followed by biological purification using the microalga Scenedesmus obliquus. In addition, the photosynthetic activity and transcription of the microalgae were examined to evaluate the toxicity of TC and TDPs. The results show that photocatalytic degradation efficiency reached 92.7% after 30 min, and 11 intermediate products were detected. The microalgae achieved a high TC removal efficiency (99.7%) after 8 days. Exposure to the degraded TC solution (D) resulted in significantly lower (p < 0.05) biomass than the pure TC (T), and S. obliquus in the T treatment showed better resilience than the D treatment. Transcriptomic assays for different treatments revealed differential gene expression mainly involving the photosynthesis, ribosome, translation and peptide metabolic progresses. The up-regulation of photosynthesis-related genes and differential expression of chloroplast genes may be important for S. obliquus to acquire high photosynthetic efficiency and growth recovery when exposed to TC and TDPs. Our study provides a reference for TC removal using a combination of catalytic degradation and microalgal purification, and it is also helpful for understanding the environmental risk of TDPs in natural aquatic environments.

Investigation on Antioxidant Activity and Different Metabolites of Mulberry (Morus spp.) Leaves Depending on the Harvest Months by UPLC-Q-TOF-MS with Multivariate Tools.

The changes in active components in mulberry leaves harvested in different months and their antioxidant activities were investigated. Ultra-high-performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) with multivariate statistical tools was used to investigate the chemical constituents in the extracts of mulberry leaves. The results indicated that mulberry leaves were rich in phenolic acids, flavonoids, organic acids, and fatty acid derivatives. In addition, 25 different compounds were identified in the different batches of mulberry leaves. The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity was measured to evaluate the in vitro antioxidant activities of mulberry leaves. Among the four batches, batch A, harvested in December, exhibited the strongest DPPH radical-scavenging activity, while batch B, harvested in March, showed the weakest activity. This was related to the total phenolic content in the mulberry leaves of each batch. The optimal harvest time of mulberry leaves greatly influences the bioactivity and bioavailability of the plant.

Study on Absorption, Distribution and Excretion of a New Candidate Compound XYY-CP1106 against Alzheimer's Disease in Rats by LC-MS/MS.

XYY-CP1106, a candidate compound synthesized from a hybrid of hydroxypyridinone and coumarin, has been shown to be remarkably effective in treating Alzheimer's disease. A simple, rapid and accurate high-performance liquid chromatography coupled with the triple quadrupole mass spectrometer (LC-MS/MS) method was established in this study to elucidate the pharmacokinetics of XYY-CP1106 after oral and intravenous administration in rats. XYY-CP1106 was shown to be rapidly absorbed into the blood (Tmax, 0.57-0.93 h) and then eliminated slowly (T1/2, 8.26-10.06 h). Oral bioavailability of XYY-CP1106 was (10.70 ± 1.72)%. XYY-CP1106 could pass through the blood-brain barrier with a high content of (500.52 ± 260.12) ng/g at 2 h in brain tissue. The excretion results showed that XYY-CP1106 was mainly excreted through feces, with an average total excretion rate of (31.14 ± 0.05)% in 72 h. In conclusion, the absorption, distribution and excretion of XYY-CP1106 in rats provided a theoretical basis for subsequent preclinical studies.

Effects of Tetracycline on Scenedesmus obliquus Microalgae Photosynthetic Processes.

Tetracycline (TC) antibiotics can be detected worldwide in the aquatic environment due to their extensive use and low utilization efficiency, and they may affect the physiological processes of non-target organisms. In this study, the acute and sub-acute toxicities of TC on the freshwater microalga Scenedesmus obliquus were investigated with an emphasis on algal photosynthesis and transcription alterations during an 8 d TC exposure. The results showed that the IC10, IC30 and IC50 values were 1.8, 4.1 and 6.9 mg/L, respectively. During sub-acute exposure, the microalgae of the IC10 treatment was able to recover comparable growth to that of the control by day 7, while significantly lower cell densities were observed in the IC30 and IC50 treatments at the end of the exposure. The photosynthetic efficiency Fv/FM of S. obliquus first decreased as the TC concentration increased and then returned to a level close to that of the control on day 8, accompanied by an increase in photosynthetic activities, including light harvesting, electron transport and energy dissipation. Transcriptomic analysis of the IC10 treatment (1.8 mg/L TC) revealed that 2157 differentially expressed genes were up-regulated and 1629 were down-regulated compared with the control. KEGG and GO enrichments demonstrated that 28 photosynthesis-related genes involving light-harvesting chlorophyll protein complex, photosystem I, photosystem II, photosynthetic electron transport and enzymes were up-regulated, which may be the factor responsible for the enhanced photosynthesis and recovery of the microalgae. Our work may be helpful not only for gaining a better understanding of the environmental risk of TC at concentrations close to the real levels in natural waters, but also for explaining photosynthesis and related gene transcription induced by antibiotics.

Metabolomics revealed the photosynthetic performance and metabolomic characteristics of Euglena gracilis under autotrophic and mixotrophic conditions.

Photosynthetic and metabolomic performance of Euglena gracilis was examined and compared under autotrophic and mixotrophic conditions. Autotrophic protozoa (AP) obtained greater biomass (about 33% higher) than the mixotrophic protozoa (MP) after 12 days of growth. AP maintained steady photosynthesis, while MP showed a remarkable decrease in photosynthetic efficiency and dropped to an extremely low level at day 12. In MP, low light absorption and photosynthetic electron transport efficiency, and high energy dissipation were reflected by the chlorophyll (chl a) fluorescence (OJIP) of the protozoa. The values of ΨO, ΦEo, and ETO/RC of MP decreased to extremely low levels, to 1/15, 1/46, and 1/9 those of AP, respectively, while DIO/RC increased to approximately 16 times that of AP. A total of 137 metabolites were showed significant differences between AP and MP. AP accumulated more monosaccharide, lipids, and alkaloids, while MP produced more amino acids, peptides, and long-chain fatty acids including poly-unsaturated fatty acids. The top nine most important enriched pathways obtained from KEGG mapping were related to ABC transporters, biosynthesis of amino acids, purine metabolism, and carbohydrate metabolism. There were significant differences between AP and MP in photosynthetic activity, metabolites, and metabolic pathways. This work presented useful information for the production of high value bioproducts in E. gracilis cultured under different nutritional conditions.

Components identification and isomers differentiation in pigeon pea (Cajanus cajan L.) leaves by LC-MS.

A valid and reliable method based on ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry using electrospray ionization was established to identify chemical constituents in the ethanol extract of pigeon pea leaves. A total of 58 compounds were detected both in positive and negative modes. Among them, 42 compounds, including 16 flavones, 1 flavonol, 5 flavanones, 9 isoflavones, 1 coumarin, 1 lactone, 6 stilbenes, 2 chalcones, and 1 other compound, were unambiguously identified or tentatively assigned in view of the retention time, the molecular formula, as well as the fragmentation patterns. Moreover, eight sets of isomers were differentiated by the ion trap mass spectrometry based on the fragment ion differences or the abundance differences of the same fragment ions. The energy-resolved mass spectrometry in light of the relative abundance of characteristic fragment ions was adopted in the study.

On the mechanism behind enhanced antibacterial activity of alkyl gallate esters against foodborne pathogens and its application in Chinese icefish preservation.

The objective of this study was to investigate antibacterial activities and action mode of alkyl gallates against three food-related bacteria. Results show that the length of the alkyl chain plays a critical role in eliciting their antibacterial activities and octyl gallate (GAC8) exhibited an outstanding bactericidal effect against these strains. A possible bactericidal mechanism of GAC8 against E. coli was fully elucidated by analyzing associated changes in cellular functions of E. coli, including assessments of membrane modification and intracellular oxidation state. Our data strongly suggested that GAC8 functions outside and inside the bacterial membrane and causes increased intracellular reactive oxygen species (hydroxyl radicals) and subsequent oxidative damage. We demonstrated that the hydroxyl radical formation induced by GAC8 is the end product of an oxidative damage cellular death pathway involving a transient depletion of NADH, the tricarboxylic acid cycle, intrinsic redox cycling activities, and stimulation of the Fenton reaction. Also, chitosan-based edible films containing GAC8 have unique superiorities for icefish preservation at 4 °C. This research highlights the effectiveness of GAC8 as an attractive antibacterial, which possesses both antioxidant and antibacterial activities and can be used as a multifunctional food additive combined with the benefit of active packaging for food preservations.

Analysis of metabolome changes in the HepG2 cells of apatinib treatment by using the NMR-based metabolomics.

Neovascularization is required for the growth of tumors, vascular endothelial growth factor (VEGF) and related signal pathways are important in tumor angiogenesis. Apatinib is a highly selective and potent antiangiogenesis drug targeting the receptor of VEGFR2, blocking downstream signal transduction and inhibiting angiogenesis of tumor tissue. Apatinib has a wide range of antitumor activities in vitro and in vivo, but its effect on metabolic changes has not deeply research at present. Nowadays, our research first systematically studied the metabolic changes affected by apatinib in the HepG2 cells at the half-maximal inhibitory concentration value. We used the metabolomics by using 1 H nuclear magnetic resonance (1 H-NMR) to analyze the HepG2 cell culture media. Multivariable Statistics was applied to analyze the 1 H-NMR spectra of the cell media, including principal component analysis, partial least squares discriminant analysis (PLS-DA) and orthogonal PLS-DA (OPLS-DA). Compared with the uncultured and cultured media (negative/positive control), the metabolic phenotypes were changed in the apatinib treatment with a continuous effect over time. The metabolic pathway analysis is shown that the mainly disturbed metabolic pathways pyruvate metabolism, alanine, aspartate, and glutamate metabolism and amino acid metabolism associated with them in the apatinib treatment. The differential metabolites which were identified from the reconstructed OPLS-DA loading plots also reflected in these disturbed metabolic pathways. Our works could allow us to well understand the therapeutic effect of apatinib, especially in metabolism.

Separation of six compounds from pigeon pea leaves by elution-extrusion counter-current chromatography.

A valid and reliable method was established to separate six compounds from pigeon pea leaves via elution-extrusion counter-current chromatography. A solvent system composed of n-hexane/methanol/formic acid aqueous solution with pH = 3 (10:6:4, v/v) was screened to achieve satisfactory isolation from the ethanol extract of pigeon pea leaves. Four compounds, 9.2 mg of compound 1 (96.8%), 3.2 mg of 2 (88.0%), 6.2 mg of 4 (94.2%) and 25.2 mg of 5 (94.2%), were obtained by conventional elution from 100 mg of the precipitation fraction, respectively. Two compounds, 14.4 mg of 3 (96.3%) and 28.1 mg of 6 (96.6%), with high K values were obtained by the subsequent extrusion procedure. The compounds 1-6 were identified as 3-methoxy-5-(2-phenylethenyl)-phenol, pinostrobin chalcone, pinostrobin, 2-hydroxy-4-methoxy-6-(2-phenylvinyl)-benzoic acid, longistylin C and cajaninstilbene acid by quadrupole time-of-flight mass spectrometry, and 1 H and 13 C NMR spectroscopy. The in vitro antiproliferation activities of compounds 1, 5 and 6 against human hepatoma cell were evaluated and the half-maximum inhibitory concentrations were acquired.

Development of Starch-Based Antifungal Coatings by Incorporation of Natamycin/Methyl-ß-Cyclodextrin Inclusion Complex for Postharvest Treatments on Cherry Tomato against Botrytis cinerea.

The application of natamycin as a natural fungicide in edible coatings is challenging because of its low aqueous solubility. In this study, the natamycin/methyl-ß-cyclodextrin (N/ME-ß-CD) inclusion complex was fabricated and incorporated into waxy corn starch-based coatings for postharvest treatments. The phase solubility of natamycin in the presence of ME-ß-CD at 293.2 K, 303.2 K, and 313.2 K is determined and used to calculate the process thermodynamic parameters. The N/ME-ß-CD inclusion complex was confirmed and characterized by FTIR and 1H NMR spectroscopy. The results indicated that the inclusion complex was formed and the hydrophobic part (C16-C26) of natamycin might be partially inserted into the cavity of ME-ß-CD form the wide rim. The effects of N/ME-ß-CD incorporated starch-based coatings (N/ME-ß-CD S coatings) on postharvest treatments of cherry tomatoes were evaluated in vivo. The N/ME-ß-CD S coatings could reduce weight loss, delay fruit ripening, and inhibit fruit decay caused by Botrytis cinerea in tomato fruit during storage.

Simultaneous Quantification and Pharmacokinetic Study of Nine Bioactive Components of Orthosiphon stamineus Benth. Extract in Rat Plasma by UHPLC-MS/MS.

Orthosiphon stamineus Benth. (OS) is a traditional folk medicine for the treatment of kidney stones and other urinary tract diseases. In this study, a rapid and sensitive Ultra high-performance liquid chromatography (UHPLC)-MS/MS approach was established and validated for the simultaneous quantification of nine bioactive components in rat plasma. The nine components from OS extract detected in rat plasma were danshensu, protocatechuic acid, caffeic acid, rosmarinic acid, salvianolic acid A, salvianolic acid B, cichoric acid, sinensetin and eupatorin. After liquid-liquid extraction with ethyl acetate, the plasma samples were subjected to a triple quadrupole mass spectrometer employing electrospray ionization (ESI) technique and operating in multiple reaction monitoring (MRM) with both positive and negative ion modes. The standard curves showed good linear regression (r > 0.9915) over the concentration range for the nine analytes. The inter-day and intra-day precision and accuracy were found to be within 15% of the nominal concentration. The recovery and stability of nine compounds were all demonstrated to be within acceptable limits. The approach was successfully applied to investigate the pharmacokinetic analysis of the nine bioactive components after oral administration of OS extract in rats.

Application of ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry in identification of three isoflavone glycosides and their corresponding metabolites.

RATIONALE: Metabolites of isoflavones have attracted much attention in recent years due to their potential bioactivities. However, the complex constituents of the metabolic system and the low level of metabolites make them difficult to analyze. A mass spectrometry (MS) method was applied in our identification of metabolites and study of their fragmentation pathways due to the advantages of rapidity, sensitivity, and low level of sample consumption. METHODS: Three isoflavone glycosides and their metabolites were identified using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/QTOF-MS). These metabolites were obtained by anaerobically incubating three isoflavone glycosides with human intestinal flora. The characteristic fragments of isoflavone glycosides and their metabolites were used for the identification work. RESULTS: Two metabolites from ononin, three metabolites from irilone-4'-O-ß-D-glucoside, and five metabolites from sissotrin were identified respectively by the retention time (RT), accurate mass, and mass spectral fragmentation patterns. The losses of the glucosyl group, CO from the [M+H]+ ion were observed for all the three isoflavone glycosides. The characteristic retro-Diels-Alder (RDA) fragmentation patterns were used to differentiate the compounds. The metabolic pathways of the three isoflavone glycosides were proposed according to the identified chemical structures of the metabolites. CONCLUSIONS: A selective, sensitive and rapid method was established for detecting and identifying three isoflavone glycosides and their metabolites using UPLC/QTOF-MS. The established method can be used for further rapid structural identification studies of metabolites and natural products. Furthermore, the proposed metabolic pathways will be helpful for understanding the in vivo metabolic process of isoflavone.

Measurements, Thermodynamic Modeling, and a Hydrogen Bonding Study on the Solubilities of Metoprolol Succinate in Organic Solvents.

The solubilities of metoprolol succinate (a cardioselective ß1 adrenergic receptor) in methanol, ethanol, n-propanol, isopropanol, n-butanol, ethyl acetate, and acetone were measured at temperatures ranging from (278.2 to 318.2) K using a solid⁻liquid equilibrium method. The solubility of metoprolol succinate increases with increasing temperature. At a fixed temperature, the solubility decreases in the order methanol > ethanol > n-butanol > n-propanol > isopropanol > acetone > ethyl acetate. The enthalpy of fusion and the melting point of metoprolol succinate were determined by differential scanning calorimetry. The thermodynamic properties of the dissolution process, determined by a van't Hoff analysis, have been obtained and are discussed. The modified Apelblat equation, Wilson model, and non-random two-liquid (NRTL) model were employed to correlate the solubilities of metoprolol succinate in different solvents. Finally, a quantitative structure⁻property relationship (QSPR) study of physical properties of solvents and density functional theory simulations of hydrogen-bonding structure were carried out to give the explanation for the sequence of solubility in alcohols. The density functional theory (DFT) calculations well illustrated that the solubility of metoprolol succinate in various alcohols can be mainly attributed to the intra- and intermolecular hydrogen bonds in metoprolol succinate-solvent complexes.

Characterization of Purified Red Cabbage Anthocyanins: Improvement in HPLC Separation and Protective Effect against H2O2-Induced Oxidative Stress in HepG2 Cells.

In this study, the chemical profiles and antioxidant activities of red cabbage anthocyanin (RCA)-enriched extract are evaluated. The effects of column temperature on the HPLC resolution of the RCAs are studied. The HPLC resolutions became better as the column temperature increased from 20 °C⁻45 °C. An optimized HPLC condition was achieved at 45 °C and used for the quantification and qualification of the RCAs. The anthocyanins in the enriched powder are all derivatives of cyanidin (268 ± 2 µg/mg), mainly with 19% nonacylated, 51% monoacylated, and 31% diacylated structures with ferulic, sinapic, p-coumaric, and caffeic acids characterized by HPLC-MS. The RCA extracts markedly reduced intracellular oxidative stress production by H2O2 on HepG2 cells and consequently ameliorated cell apoptosis and improved viability. The analytical method and cellular antioxidant activity demonstration of the RCAs will greatly facilitate their functional applications.

Separation and identification of phenolic compounds in Bidens pilosa L. by ultra high performance liquid chromatography with quadrupole time-of-flight mass spectrometry.

A validated method based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry was established to separate and identify phenolic compounds in Bidens pilosa L. Mass spectrometry experiments were performed both in positive and negative ion modes. A total of 35 compounds were detected, and 26 phenolic compounds were unequivocally identified or tentatively assigned based on retention time, maximum UV absorption, molecular formula, and fragments. The ultra high performance liquid chromatography method was validated and showed good linearity (R(2) ≧ 0.9996) over the test range. The limits of detection and quantification were above 0.072 and 0.162 µg/mL, respectively. The relative standard deviations of intraday and interday precision were below 0.3 and 1.6%, respectively.

Fragmentation pathways of synthetic and naturally occurring coumarin derivatives by ion trap and quadrupole time-of-flight mass spectrometry.

RATIONALE: Synthetic and natural coumarin derivatives possess a wide range of biological activities. Fragmentation pathway studies are important in identifying both naturally occurring coumarins and synthetic coumarins with novel structures and properties. METHODS: The fragmentation pathways of eleven coumarin derivatives are investigated by electrospray ionization (ESI) ion-trap mass spectrometry (ESI-ITMSn ) and ESI quadrupole time-of-flight mass spectrometry (QTOFMS) in positive mode. Compounds 1-9 in this study were newly synthesized in our laboratory. Compounds 10 and 11 were isolated from the root of Zanthoxylum armatum. RESULTS: The major fragmentation pathways for 11 coumarin derivatives are greatly affected by the heterocyclic ring structures and the side-chain substituents. Typical losses of small neutral molecules, such as CH3 CH2 OH, CH2 =CH2 , CO, and H2 O, are observed for compounds 1-5. Compounds 6-9 share similar fragmentation pathways through losses of CO, aromatic rings, and the coumarin skeleton. The main product ions at m/z 205, 219, and 220 observed for compounds 10 and 11 are produced by the loss of C5 H12 O2 , C4 H10 O2 , and the C4 H9 O2 radical, respectively. CONCLUSIONS: The fragmentation pathways of 11 coumarin derivatives are elucidated based on ITMSn and QTOFMS spectral data. Differences in the structures of the heterocyclic rings and side-chain substituents strongly affect the fragmentation pathways of the coumarins. The present results will facilitate further research into the fragmentation pathways and structural characterization of these classes of compounds with diverse structures. Copyright © 2015 John Wiley & Sons, Ltd.

Multi-constituent determination and fingerprint analysis of Scutellaria indica L. using ultra high performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

An ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry method integrating multi-constituent determination and fingerprint analysis has been established for quality assessment and control of Scutellaria indica L. The optimized method possesses the advantages of speediness, efficiency, and allows multi-constituents determination and fingerprint analysis in one chromatographic run within 11 min. 36 compounds were detected, and 23 of them were unequivocally identified or tentatively assigned. The established fingerprint method was applied to the analysis of ten S. indica samples from different geographic locations. The quality assessment was achieved by using principal component analysis. The proposed method is useful and reliable for the characterization of multi-constituents in a complex chemical system and the overall quality assessment of S. indica.

Improvement on solubility of fluticasone propionate with cyclodextrins by mechanochemical activation.

To enhance the solubility and in vitro dissolution of fluticasone propionate (FP), a novel approach was developed with mechanochemical treatment. The order of solubilizing effect of ß-CD derivatives was observed as HP-ß-CD-SBE-ß-CD-ß-CD-HE-ß-CD, consequently, HP-ß-CD showed the highest stability constant. To further improve FP solubility, FP and HP-ß-CD were grinded using a roll mill, the optimal conditions, determined through single factor experiments, were as follows: rotation frequency of 60 Hz; milling time of 6h. mass ratio of 1: 7. In comparison with pure FP, a 280-fold increase in solubility and a 2.15-fold higher dissolution rate of ground mixture was obtained. The characterization of FP and HP-ß-CD complexes had been analyzed by scanning electron microscopy (SEM), differential scanning calorimetry (DSC), powder X-ray diffractometry (PXRD) and fourier transform infrared spectroscopy (FT-IR). The results suggested that the interaction between FP and HP-ß-CD was strengthened and an amorphous ground mixture was gained. After stored for 60 days, the ground mixtures were stable both chemically and physically.

The application of quantitative NMR for the facile, rapid and reliable determination of clindamycin phosphate in a conventional tablet formulation.

Spectroscopic tools such as NMR can be applied to the quantitative analysis of active pharmaceutical ingredients with relative ease and accuracy. Here, we demonstrate the quantification of clindamycin phosphate (CLP) in a conventional tablet formulation, performed using potassium hydrogen phthalate (KHP) as the internal standard and deuterium oxide (D2O) as the NMR solvent. The methyl protons signal of CLP at 0.72 ppm (triplet) relative to the signal of KHP at 7.37-7.40 ppm (multiplet) was used for quantification purposes using (1)H NMR. This method was shown to be specific and linear (r = 0.9997) within the CLP concentration range from 7.2 to 23.1 mg per 0.5 ml of D2O. The maximum relative standard deviation (RSD) of accuracy and precision was calculated at 0.39% and 0.64%, respectively. The limits of detection (LOD) and quantification were 0.04 and 0.11 mg/ml, respectively. The method was highly stable with a calculated RSD of 0.03%. The robustness of the method was demonstrated by changing four different parameters, and the difference among each parameter was ≤ 0.78%. The findings of this work were in good agreement with previously reported conventional HPLC-based approaches, highlighting its applicability in the determination of other active pharmaceutical ingredients in conventional formulations for quality control purposes.

Quantitative determination and validation of avermectin B1a in commercial products using quantitative nuclear magnetic resonance spectroscopy.

Nuclear magnetic resonance is defined as a quantitative spectroscopic tool that enables a precise determination of the number of substances in liquids as well as in solids. There is few report demonstrating the application of NMR in the quantification of avermectin B1a (AVB1a ); here, a proton nuclear magnetic resonance spectroscopy ((1) H NMR) using benzene [1-methoxy-4-(2-nitroethyl) (PMN)] as an internal standard and deuterochloroform as an NMR solvent was tested for the quantitative determination of AVB1a . The integrated signal of AVB1a at 5.56 ppm and the signal of PMN at 8.14 ppm in the (1) H NMR spectrum were used for quantification purposes. Parameters of specificity, linearity, accuracy, precision, intermediate precision, range, limit of detection (LOD), limit of quantification (LOQ), stability and robustness were validated. The established method was accurate and precise with good recovery (98.86%) and relative standard deviation (RSD) of assay (0.34%) within the linearity of the calibration curve ranging from 5.08 to 13.58 mg/ml (R(2) = 0.9999). The LOD and LOQ were 0.009 and 0.029 mg/ml, which indicated the excellent sensitivity of the method. The stability of the method was testified by a calculated RSD of 0.11%. The robustness was testified by modification of four different parameters, and the differences among each parameter were all less than 0.1%. Comparing with the assay described by the manufacturer of avermectin tablets, there was no significant difference between the assay obtained by HPLC and quantitative NMR (qNMR), which indicated qNMR was a simple and efficient method for the determination of AVB1a in commercial formulation products.