Influence of sulfur fumigation on the chemical constituents and antioxidant activity of buds of Lonicera japonica

Lonicerae Japonicae Caulis: a review of its research progress of active metabolites and pharmacological effects

Lonicerae Japonicae Caulis is the aboveground stem part of the Lonicera Japonica Thunb, which belongs to the medicine food homology species in China. It has the effects of clearing away heat, toxic material, dredging wind and unblocking collaterals. Modern research shows that it contains various active metabolites and a wide range of pharmacological effects, which is of great research and clinical application value. It mainly contains organic acids, volatile oils, flavonoids, triterpenes, triterpene saponins and other active metabolites. Its pharmacological effects mainly include anti-inflammatory, antibacterial, antitumor, antioxidant, and repairing bone and soft tissue. Based on the literature reports in recent years, the active metabolites, pharmacological effects and mechanisms of Lonicerae Japonicae Caulis were sorted out and summarized. It lays a foundation for explaining the efficacy material basis and application value of Lonicerae Japonicae Caulis. It aims to provide a reference for the in-depth research, development and utilization of Lonicerae Japonicae Caulis.

Comparison of the antioxidant activities of nonfumigated and sulphur-fumigated Chrysanthemum morifolium cv. Hang-ju induced by oxidative stress

CONTEXT

The traditional drying method, sun drying, for Chrysanthemum morifolium Ramat. cv. Hang-ju (Compositae) (HJ) is widely replaced by sulphur fumigation (SF), which has an unknown effect on its efficacy.

OBJECTIVE

To investigate protective effects of nonfumigated HJ (NHJ) and sulphur-fumigated HJ (SHJ) water extracts against oxidative stress and lipid peroxidation.

MATERIALS AND METHODS

Sprague-Dawley rats were administered high-fat diet to induce hyperlipidaemia and randomly divided into eight groups (n = 6): control, fenofibrate, NHJ and SHJ extracts (1, 2 or 4 g crude drugs/kg/d; intragastric administration for 8 weeks). Serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), superoxide dismutase (SOD) and malondialdehyde (MDA) levels were detected. Human umbilical vein endothelial cells (HUVECs) were treated with NHJ and SHJ extracts (50, 100 or 200 μg/mL) for 24 h, followed by oxidized low-density lipoprotein (ox-LDL, 20 μg/mL) for 2 h in vitro. Cellular reactive oxygen species (ROS), SOD and MDA levels and apoptosis were evaluated.

RESULTS

NHJ was more effective than SHJ in decreasing serum TG, TC, LDL-C, LDL/HDL and MDA while increasing serum HDL-C and SOD levels at high doses. SHJ (IC₅₀=19.9 mg/mL) suppressed HUVEC growth stronger than NHJ (IC₅₀=186.7 mg/mL). At 200 μg/mL, NHJ was more effective than SHJ in downregulating ROS and MDA levels, reducing HUVECs apoptosis rate and elevating SOD activity in ox-LDL-treated HUVECs.

CONCLUSIONS

SF causes oxidative damage and attenuates antioxidative activity in ox-LDL-treated HUVECs, which promotes lipid peroxidation. SF is not recommended for processing HJ.

Potential Application of Lonicera japonica Extracts in Animal Production: From the Perspective of Intestinal Health

Lonicera japonica (L. japonica) extract is rich in active substances, such as phenolic acids, essential oils, flavones, saponins, and iridoids, which have a broad spectrum of antioxidant, anti-inflammatory, and anti-microbial effect. Previous studies have demonstrated that L. japonica has a good regulatory effect on animal intestinal health, which can be used as a potential antibiotic substitute product. However, previous studies about intestinal health regulation mainly focus on experimental animals or cells, like mice, rats, HMC-1 Cells, and RAW 264.7 cells. In this review, the intestinal health benefits including antioxidant, anti-inflammatory, and antimicrobial activity, and its potential application in animal production were summarized. Through this review, we can see that the effects and mechanism of L. japonica extract on intestinal health regulation of farm and aquatic animals are still rare and unclear. Further studies could focus on the regulatory mechanism of L. japonica extract on intestinal health especially the protective effects of L. japonica extract on oxidative injury, inflammation, and regulation of intestinal flora in farm animals and aquatic animals, thereby providing references for the rational utilization and application of L. japonica and its extracts in animal production.

A Practical Protocol for a Comprehensive Evaluation of Sulfur Fumigation of Trichosanthis Radix Based on Both Non-Targeted and Widely Targeted Metabolomics

Trichosanthis Radix (TR) is one of the most severely sulfur-fumigated herbs in the market, whose transformation mechanism of chemical compositions and sulfur-fumigation markers of TR have not been clarified. To excavate characteristic sulfur-fumigation markers of TR samples, this study brings up a practical protocol using both ultra-performance liquid chromatography/quadrupole time-of-flight-mass spectrum (UPLC-ESI-QTOF-MS/MS)-based non-targeted metabolomics and ultra-performance liquid chromatography/electrospray ionization/quadrupole multiple-stage linear ion-trap mass spectrum (UPLC-ESI-QTRAP-MS/MS)-based widely targeted metabolomics. The results of study demonstrated that five characteristic markers are sulfur-containing components, which were identified as p-Hydroxybenzyl hydrogen sulfite, cucurbitacin D sulfite I, cucurbitacin D sulfite II, cucurbitacin B sulfite I, and cucurbitacin B sulfite II, respectively. Additionally, cucurbitacin B and D were also filtered and identified as the characteristic sulfur-fumigation markers. Meanwhile, the different sulfur-fumigation extent of TR samples was tested by chemical transformations analysis and sulfur dioxide residues test. Further, 58.16% (139 of 239) of the differential metabolites content significantly reduced in sulfur-fumigated TR samples. Besides, 20 kinds of non-sulfur marker metabolites were tested to evaluate the quality of TR samples before and after sulfur fumigation, predominantly including phenolic acids, amino acids, lipids and nucleotides. Taking TR as an example, this work provides a comprehensive practical protocol for the quality supervision of sulfur-fumigation herbs.

The effects of sulfur fumigation processing on Panacis Quinquefolii Radix in chemical profile, immunoregulation and liver and kidney injury

ETHNOPHARMACOLOGICAL RELEVANCE

The influence of sulfur fumigation processing on chemical profile, pharmacological activity and safety of Chinese herbs has attracted great attention. Panacis Quinquefolii Radix (PQR) was more widely used as edible and medicinal than Ginseng because of its tonifying effect and characteristic of not getting inflamed. The disadvantage of sulfur fumigated (SF) Ginseng has been reported, but the systematic study of SF-PQR is deficient and urgently needed.

AIM OF THE STUDY

To systematically describe the influence of sulfur fumigation on chemical profile, characteristic products, immunoregulation and liver and kidney injury of PQR.

MATERIALS AND METHODS

ICP-MS and HPLC-DAD were used to detect 11 inorganic elements and 3 ginsenosides, respectively. Principal component analysis (PCA) was used to distinguish SF-PQR from non-sulfur fumigated (NSF)-PQR by combining the content changes of inorganic elements and ginsenosides. UPLC/Orbitrap-MS was applied to screen the characteristic products (m/z) after sulfur fumigation. For the effectiveness and safety, male KM mice were used to compare the immunomodulatory effects of NSF-PQR or SF-PQR under both healty and cyclophosphamide induced immunosuppressive conditions by net growth rate of body weight, thymus and spleen indices, serum IL-6, SOD, BUN, AST levels, and HE staining of liver and kidney.

RESULTS

Sulfur fumigation processing significantly reduced the contents of ginsenosides Rb₁, Re and Rg₁ with the elevation of inorganic elements in 20 batches PQR. Based on the scatter distribution of PCA, SF-PQR and NSF-PQR can be distinguished. According to the Rt, Precursor ion (m/z) and Product ion (m/z) produced by UPLC/Orbit trap-MS, R₁-SO₃ (m/z, 1059.53), Re-SO₃ (m/z, 1025.55), Rg₁-SO₃ (m/z, 878.47), Ro-SO₃ (m/z, 1035.32), Rb₁-SO₃ (m/z, 1179.58), and Rk₃-SO₃ (m/z, 745.40) could be confirmed as important markers for identifying SF-PQR. The effect of SF-PQR on reversing immunosuppression induced by cyclophosphamide was significantly reduced (P < 0.05) evidenced by the inhibition of net growth rate of body weight, immune organ index, IL-6 level and SOD activity. For healthy mice, SF-PQR not only failed to maintain the normal indexes, but also reduced the indexes to lower levels. After 2 weeks of continuous gastric administration, the abnormal liver and kidney functions in healthy mice were damaged and manifested by the increasing of BUN and AST levels, which was consistent with hepatic lesion area and renal tubular injury observed by HE staining.

CONCLUSION

Sulfur fumigation processing not only reduced the immunomodulatory effect of PQR, but also brought the hidden danger in liver and kidney injury. The sulfonated products provided in this paper can be applied for the identification of SF-PQR accurately.

Lonicerae japonicae flos and Lonicerae flos: a systematic review of ethnopharmacology, phytochemistry and pharmacology

Lonicerae japonicae flos (called Jinyinhua, JYH in Chinese), flowers or flower buds of Lonicera japonica Thunberg, is an extremely used traditional edible-medicinal herb. Pharmacological studies have already proved JYH ideal clinical therapeutic effects on inflammation and infectious diseases and prominent effects on multiple targets in vitro and in vivo, such as pro-inflammatory protein inducible nitric oxide synthase, toll-like receptor 4, interleukin-1 receptor. JYH and Lonicerae flos [called Shanyinhua, SYH in Chinese, flowers or flower buds of Lonicera hypoglauca Miquel, Lonicera confusa De Candolle or Lonicera macrantha (D.Don) Spreng] which belongs to the same family of JYH were once recorded as same herb in multiple versions of Chinese Pharmacopoeia (ChP). However, they were listed as two different herbs in 2005 Edition ChP, leading to endless controversy since they have close proximity on plant species, appearances and functions, together with traditional applications. In the past decades, there has no literature regarding to systematical comparison on the similarity concerning research achievements of the two herbs. This review comprehensively presents similarities and differences between JYH and SYH retrospectively, particularly proposing them the marked differences in botanies, phytochemistry and pharmacological activities which can be used as evidence of separate list of JYH and SYH. Furthermore, deficiencies on present studies have also been discussed so as to further research could use for reference.

Nrf2 participates in mechanisms for reducing the toxicity and enhancing the antitumour effect of Radix Tripterygium wilfordii to S180-bearing mice by herbal-processing technology

Context: Radix Tripterygium wilfordii Hook. f. (Celastraceae) (LGT) has outstanding curative efficacy; however, side effects include high toxicity, particularly hepatotoxicity and nephrotoxicity. Objective: To investigate detoxification mechanisms of LGT through processing separately with each of these medicinal herbs including Flower Lonicera japonica Thunb. (Caprifoliaceae) (JYH), Radix Paeonia lactiflora Pall. (Ranunculaceae) (BS), Herba Lysimachia christinae Hance (Primulaceae) (JQC), Radix et Rhizoma Glycyrrhiza uralensis Fisch. (Fabaceae) (GC) and Seed Phaseolus radiatus L. (Fabaceae) (LD) in S180-bearing mice by involving nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Materials and methods: LGT raw and processed products were orally administered at 60 mg/kg to KM male mice inoculated with S180 tumour cells for 14 consecutive days, and blood, tumour, liver and kidney were taken to observe the detoxifying effects and biological mechanisms. Results: Herbal-processing technology significantly weakened hepatotoxicity and nephrotoxicity evoked by LGT with ED₅₀ of the converted triptolide in each processed-herb product for serum alanine transaminase, aspartate transaminase, creatinine and urea nitrogen of 9.3, 16.6, 2.5 and 4.2 μg/kg, for liver glutathione, glutathione S-transferase, catalase, tumour necrosis factor-α and interleukin-10 of 114.9, 67.8, 134.1, 7.7, 4171.6 μg/kg, and for kidney 21.9, 20.5, 145.0, 529.7, 19.4 μg/kg, respectively. Moreover, herbal-processing technology promoted the accumulation of Nrf2 into the nucleus, and upregulated mRNA expression of Nrf2 and heme oxygenase-1. Additionally, herbal-processing technology enhanced the tumour inhibition rate with ED₅₀ 12.2 μg/kg. Discussion and conclusions: Herbal-processing technology improves the safety and effectiveness of LGT in cancer treatment, and future research may be focused on the Nrf2-related molecules.

A proposed protocol based on integrative metabonomics analysis for the rapid detection and mechanistic understanding of sulfur fumigation of Chinese herbal medicines

In the current work, Lonicera japonica Flos (FLJ) was selected as a model Chinese herbal medicine (CHM) and a protocol was proposed for the rapid detection of sulfur-fumigated (SF) CHMs. A multiple metabonomics analysis was conducted using HPLC, NIR spectroscopy and a UHPLC-LTQ-Orbitrap mass spectrometer. First, the group discriminatory potential of each technique was respectively investigated based on PCA. Then, the effect of mid-level metabonomics data fusion on sample spatial distribution was evaluated based on data obtained using the above three technologies. Furthermore, based on the acquired HRMS data, 76 markers discriminating SF from non-sulfur-fumigated (NSF) CHMs were observed and 49 of them were eventually characterized. Moreover, NIR absorptions of 18 sulfur-containing markers were identified to be in close correlation with the discriminatory NIR wavebands. In conclusion, the proposed protocol based on integrative metabonomics analysis that we established for the rapid detection and mechanistic explanation of the sulfur fumigation of CHMs was able to achieve variable selection, enhance group separation and reveal the intrinsic mechanism of the sulfur fumigation of CHMs.

A Simple, Rapid, and Practical Method for Distinguishing Lonicerae Japonicae Flos from Lonicerae Flos

Lonicerae japonicae flos (LJF), the dried flower buds of Lonicera japonica Thunb., are often adulterated with Lonicerae. flos (LF), which is derived from the other four Lonicera species. Scholars at home and abroad have established several analytical methods to distinguish LJF from the four Lonicera species of LF; however, to date, no effective and practical method has been established for distinguishing LF from LJF. In our present study, the HPLC fingerprints of LJF and LF were compared, and differences in the content of one of the iridoids were found. Column chromatography combined with pre-HPLC was used for isolating and preparing the iridoid, and its structure was identified as secologanic acid. Then, a method for determining the content of secologanic acid was established using HPLC. The amounts of secologanic acid in 34 batches of LJF and 38 batches of LF were determined. The average amount of secologanic acid in 34 batches of LJF was 18.24 mg/g, with values ranging from 12.9 mg/g to 23.3 mg/g, whereas the average amount in 38 batches of LF was 1.76 mg/g, with values ranging from 0.2 mg/g to 7.2 mg/g. Therefore, secologanic acid can be considered as one of the characteristic components for distinguishing LJF and LF. Our study not only provides a rapid, simple, sensitive, and practical method for identifying LJF and LF but also establishes a method for discovering the characteristic components of other herb-medicines that are susceptible to adulteration.

Spectrum-effect relationship study between HPLC fingerprints and antioxidant of honeysuckle extract

Honeysuckle (Lonicera japonica flos) is a well-known agent of edible and medicinal value in China and its antioxidative activity makes a major contribution to its dual use. However, the compounds responsible for its antioxidative activity are still unknown. In this study, 10 batches of honeysuckle were collected from different origins in China. The fingerprints were established by HPLC technique to investigate the compounds and a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity assay was carried out to evaluate their antioxidant activity. partial least squares regression analysis was applied to set up the regression equation between DPPH radical scavenging activity and average peak area of common peaks of fingerprints. The results showed that peaks 10 (isochlorogenic acid B), 12 (isochlorogenic acid C), 11 (isochlorogenic acid A) and 9 (cynaroside) in the fingerprints were closely related to the antioxidant activity of 50% methanol extracts of honeysuckle. This study successfully established the spectrum-effect relationship between HPLC fingerprints and DPPH radical scavenging activity and provided a general model for exploring active components with a combination of chromatography and efficacy.

Rapid Determination of Chlorogenic Acid, Luteoloside and 3,5-O-dicaffeoylquinic Acid in Chrysanthemum Using Near-Infrared Spectroscopy

The feasibility of near-infrared spectroscopy (NIR) to detect chlorogenic acid, luteoloside and 3,5-O-dicaffeoylquinic acid in Chrysanthemum was investigated. An NIR spectroradiometer was applied for data acquisition. The reference values of chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid of the samples were determined by high-performance liquid chromatography (HPLC) and were used for model calibration. The results of six preprocessing methods were compared. To reduce input variables and collinearity problems, three methods for variable selection were compared, including successive projections algorithm (SPA), genetic algorithm-partial least squares regression (GA-PLS), and competitive adaptive reweighted sampling (CARS). The selected variables were employed as the inputs of partial least square (PLS), back propagation-artificial neural networks (BP-ANN), and extreme learning machine (ELM) models. The best performance was achieved by BP-ANN models based on variables selected by CARS for all three chemical constituents. The values of r_p² (correlation coefficient of prediction) were 0.924, 0.927, 0.933, the values of RMSEP were 0.033, 0.018, 0.064 and the values of RPD were 3.667, 3.667, 2.891 for chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid, respectively. The results indicated that NIR spectroscopy combined with variables selection and multivariate calibration methods could be considered as a useful tool for rapid determination of chlorogenic acid, luteoloside, and 3,5-O-dicaffeoylquinic acid in Chrysanthemum.

Lonicera japonica extends lifespan and healthspan in Caenorhabditis elegans

Lonicera japonica (LJ) is widely used as the local medicine to improve body and prevent ills in China, but mechanisms of its healthy beneficial effects remain largely unclear. Here, we evaluated the anti-aging and healthspan promoting activities of 75% ethanol extract of LJ (LJ-E) in the animal model Caenorhabditis elegans. Our results showed that LJ-E (500 μg/mL) treatment enhanced the mean lifespan of worms by over 21.87% and significantly improved age-associated physiological functions in C. elegans. The 500 μg/mL concentration of LJ-E enhanced the survival rates under oxidative and thermal stresses, and decreased reactive oxygen species (ROS) levels and fat accumulation in the worms. Gene-specific mutant studies showed that LJ-E-mediated lifespan extension was dependent on mev-1, daf-2, daf-16, and hsf-1, but not eat-2 genes. LJ-E could upregulate stress-inducible genes, viz., hsp-16.2, sod-3 and mtl-1. Moreover, we found that the D1086.10 protein interacted with superoxide dismutase (SOD)-3 by functional protein association networks analysis according to RNA-sequencing results. It was confirmed that D1086.10 was needed to promote longevity, and positively regulated expression of sod-3 by using D1086.10 mutants. Furthermore, LJ-E significantly delayed amyloid β-protein induced paralysis in CL4176 strain. Given the important role of autophagy in aging and protein homeostasis, we observed that LJ-E could remarkably increase the mRNA expression of autophagy gene bec-1 in CL4176 strain, and decrease expression of autophagy substrate p62 protein by more than 40.0% in BC12921 strain. Finally, we found that combination composed of three major compounds (54 μg/mL chlorogenic acid, 15 μg/mL 1,5-dicaffeoylquinic acid and 7.5 μg/mL 1,3-dicaffeoylquinic acid) of 500 μg/mL LJ-E could significantly delay paralysis in CL4176 worms caused by Aβ toxicity, comparable to that of LJ-E. Overall, our study may have important implications in using Lonicera japonica to promote healthy aging and have a potency to design therapeutics for age-related diseases.

Iridoids, Phenolic Compounds and Antioxidant Activity of Edible Honeysuckle Berries (Lonicera caerulea var. kamtschatica Sevast.)

Iridoid and polyphenol profiles of 30 different honeysuckle berry cultivars and genotypes were studied. Compounds were identified by ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC-ESI-qTOF-MS/MS) in positive and negative ion modes and quantified by HPLC-PDA. The 50 identified compounds included 15 iridoids, 6 anthocyanins, 9 flavonols, 2 flavanonols (dihydroflavonols), 5 flavones, 6 flavan-3-ols, and 7 phenolic acids. 8-epi-Loganic acid, pentosyl-loganic acid, taxifolin 7-O-dihexoside, and taxifolin 7-O-hexoside were identified in honeysuckle berries for the first time. Iridoids and anthocyanins were the major groups of bioactive compounds of honeysuckle constituents. The total content of quantified iridoids and anthocyanins was between 128.42 mg/100 g fresh weight (fw) (‘Dlinnoplodnaya’) and 372 mg/100 g fw (‘Kuvshinovidnaya’) and between 150.04 mg/100 g fw (‘Karina’) and 653.95 mg/100 g fw (‘Amur’), respectively. Among iridoids, loganic acid was the dominant compound, and it represented between 22% and 73% of the total amount of quantified iridoids in honeysuckle berry. A very strong correlation was observed between the antioxidant potential and the quantity of anthocyanins. High content of iridoids in honeysuckle berries can complement antioxidant properties of phenolic compounds.

Antioxidant and anti-inflammatory activities of Lonicera japonica Thunb. var. sempervillosa Hayata flower bud extracts prepared by water, ethanol and supercritical fluid extraction techniques

Lonicera japonica Thunberg (LJ) has long been used as an antipyretic, anti-inflammatory and anti-infectious agent in East Asia. The subspecies L. japonica Thunb. var. sempervillosa Hayata (LJv) is a variant that mainly grows in Taiwan. This study examined the antioxidant and anti-inflammatory activities of the extracts from the flower buds of these two species. The extracts were obtained by three extraction methods: water extraction, ethanol extraction, and supercritical-CO2 fluid extraction (SFE). The antioxidant activities of dry LJ (dLJ) extracts were superior to those of LJv extracts. Water extracts possessed higher activities than that prepared by ethanol or SFE. The total polyphenols content, total flavonoids content, and the amount of chlorogenic acid and luteolin-7-O-glucoside were all higher in the water extracts compared to the other two. The SFE extracts of these two species all exhibited excellent anti-inflammatory activities. Although the water and ethanol extracts of dLJ extracts had higher anti-inflammatory activity than that of LJv extracts, the SFE extracts prepared from fresh LJv flower buds (fLJv) exhibited the highest activity among all extracts. The SFE effectively isolates the bioactive components of L. japonica and can obtain the L. japonica extracts with high anti-inflammatory activity.

Identification of Iridoids in Edible Honeysuckle Berries (Lonicera caerulea L. var. kamtschatica Sevast.) by UPLC-ESI-qTOF-MS/MS

Iridoid profiles of honeysuckle berry were studied. Compounds were identified by ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry UPLC-ESI-qTOF-MS/MS in positive and negative ions mode. The MS fragmentation pathways of detected iridoid glycosides were also studied in both modes. In the negative ESI mass spectra, iridoids with a methyl ester or lactone structure have preferentially produced adduct [M + HCOOH - H](-) ions. However, protonated ions of molecular fragments, which were released by glycosidic bond cleavage and following fragmentation of aglycone rings, were more usable for iridoid structure analysis. In addition, the neutral losses of H₂O, CO, CO₂, CH₃OH, acetylene, ethenone and cyclopropynone have provided data confirming the presence of functional substituents in the aglycone. Among the 13 iridoids, 11 were identified in honeysuckle berries for the first time: pentosides of loganic acid (two isomers), pentosides of loganin (three isomers), pentosyl sweroside, and additionally 7-epi-loganic acid, 7-epi-loganin, sweroside, secologanin, and secoxyloganin. The five pentoside derivatives of loganic acid and loganin have not been previously detected in the analyzed species. Honeysuckle berries are a source of iridoids with different structures, compounds that are rarely present in fruits.

Pharmacokinetics of isochlorgenic acid C in rats by HPLC-MS: Absolute bioavailability and dose proportionality

ETHNOPHARMACOLOGICAL RELEVANCE

Isochlorgenic acid C (IAC), one of the bioactive compounds of Lonicera japonica, exhibited diverse pharmacological effects. However, its pharmacokinetic properties and bioavailability remained unresolved.

AIM OF THE STUDY

To determine the absolute bioavailability in rats and the dose proportionality on the pharmacokinetics of single oral dose of IAC.

MATERIALS AND METHODS

A validated HPLC-MS method was developed for the determination of IAC in rat plasma. Plasma concentration versus time data were generated following oral and intravenous dosing. The pharmacokinetic analysis was performed using DAS 3.0 software analysis. Absolute bioavailability in rats was determined by comparing pharmacokinetic data after administration of single oral (5, 10 and 25mgkg(-1)) and intravenous (5mgkg(-1)) doses of IAC. The dose proportionality of AUC(0-∞) and Cmax were analyzed by linear regression.

RESULTS

Experimental data showed that absolute oral bioavailability of IAC in rats across the doses ranged between 14.4% and 16.9%. The regression analysis of AUC(0-∞) and Cmax at the three doses (5, 10 and 25mgkg(-1)) indicated that the equations were y=35.23x+117.20 (r=0.998) and y=121.03x+255.74 (r=0.995), respectively.

CONCLUSIONS

A new HPLC-MS method was developed to determine the bioavailability and the dose proportionality of IAC. Bioavailability of IAC in rats was poor and both Cmax and AUC(0-∞) of IAC had a positive correlation with dose. Evaluation of the pharmacokinetics of IAC will be useful in assessing concentration-effect relationships for the potential therapeutic applications of IAC.