Pilot study of rosiglitazone as an in vivo probe of paclitaxel exposure

AIMS

To evaluate the use of rosiglitazone and the erythromycin breath test (ERMBT), as probes of CYP2C8 and CYP3A4, respectively, to explain inter-individual variability in paclitaxel exposure.

METHODS

The concentration of rosiglitazone at 3 h and ERMBT results were included in a regression model to explain the variability in paclitaxel exposure in 14 subjects.

RESULTS

Rosiglitazone concentration was significantly correlated with paclitaxel exposure (P = 0.018) while ERMBT had no predictive value (P = 0.47).

CONCLUSIONS

The correlation between the exposure of rosiglitazone and paclitaxel likely reflects mutual dependence on the activity of CYP2C8. Rosiglitazone or similar agents may have value as in vivo probes of CYP2C8 activity.     

A study on the extracts of Cuscuta reflexa Roxb. in treatment of cyclophosphamide induced alopecia

Background

Alopecia is a dermatological disorder with psychosocial implications on patients with hair loss. Hair loss is one of the most feared side effects of chemotherapy. Plants have been widely used for hair growth promotion since ancient times in Ayurveda, Chinese and Unani systems of medicine. The effect of extracts of Cuscuta reflexa Roxb. in testosterone induced alopecia was reported.

Objective

In the present study, the efficacies of the extracts of Cuscuta reflexa in promoting hair growth in cyclophosphamide-induced hair loss have been determined.

Materials and methods

The study was performed by treated with petroleum ether and ethanolic extract of Cuscuta reflexa at the dose 250 mg/kg in male swiss albino rats. Cyclophosphamide (125 mg/kg) was used to induce alopecia.

Results

Groups treated with extracts of plant showed hair regrowth. Histopathology and gross morphologic observations for hair regrowth at shaved sites revealed active follicular proliferation.

Conclusions

It concluded that extracts of Cuscuta reflexa shown to be capable of promoting follicular proliferation or preventing hair loss in cyclophosphamide-induced hair fall.     

WSS45, a sulfated a-D-glucan, strongly interferes with Dengue 2 virus infection in vitro

Aim:

To investigate the mode of action of WSS45, one sulfated derivative of an α-D-glucan from the Gastrodia elata Bl, on the multiplication cycle of dengue virus serotype 2 (DV2), including initial infection and intracellular replication.

Methods:

Virus multiplication in BHK cells were monitored by qRT-PCR, plaque reduction assay, and flow cytometry. Initial virus infection was dissected into adsorption and penetration steps by converting temperature and treating by acid glycine. Surface bound virions were detected by immunofluorescence staining for Evelope protein.

Results:

WSS45 effectively inhibited DV2 infection in BHK cells with an EC₅₀ value of 0.68±0.17 μg/mL , mainly interfered with virus adsorption, in a very early stage of the virus cycle. However, WSS45 showed no viricidal effect. Moreover, WSS45 could increase the detaching of virus from cell surface in BHK cell line.

Conclusion:

WSS45 exerted potent inhibitory effect on DV2 through interfering with the interaction between viruses and targeted cells. This activity was related to its molecular size.     

Fungal transformation of androsta-1,4-diene-3,17-dione by Aspergillus brasiliensis

Background

The biotransformation of steroids by fungal biocatalysts has been recognized for many years. There are numerous fungi of the genus Aspergillus which have been shown to transform different steroid substances. The possibility of using filamentous fungi Aspergillus brasiliensis cells in the biotransformation of androsta-1,4-diene-3,17-dione, was evaluated.

Methods

The fungal strain was inoculated into the transformation medium which supplemented with androstadienedione as a substrate and fermentation continued for 5 days. The metabolites were extracted and isolated by thin layer chromatography. The structures of these metabolites were elucidated using ¹H-NMR, broadband decoupled ¹³C-NMR, EI Mass and IR spectroscopies.

Results

The fermentation yielded one reduced product: 17β-hydroxyandrost-1,4-dien-3-one and two hydroxylated metabolites: 11α-hydroxyandrost-1,4-diene-3,17-dione and 12β-hydroxyandrost-1,4-diene-3,17-dione.

Conclusions

The results obtained in this study show that A. brasiliendsis could be considered as a biocatalyst for producing important derivatives from androstadienedione.     

Risk Factors for and Outcomes of Bacteremia Caused by Extended-Spectrum ?-Lactamase–Producing Escherichia coli and Klebsiella Species at a Canadian Tertiary Care Hospital

Background:

Antimicrobial resistance due to production of extended-spectrum ß-lactamases by Escherichia coli and Klebsiella species (ESBL-EK) is concerning. Previous studies have shown that bacteremia due to ESBL-producing organisms is associated with increases in length of stay and/or mortality rate. Rates of infection by ESBL-EK vary worldwide, and regional differences in the prevalence of risk factors are likely. Few Canadian studies assessing risk factors for ESBL-EK infections or the outcomes of empiric therapy have been published.

Objectives:

To determine risk factors for and patient outcomes associated with ESBL-EK bacteremia. The appropriateness of empiric antibiotic therapy and the effect of inappropriate empiric therapy on these outcomes were also examined.

Methods:

In a retrospective, 1:1 case–control study conducted in a tertiary care hospital between 2005 and 2010, data for 40 patients with ESBL-EK bacteremia were compared with data for 40 patients who had non-ESBL-EK bacteremia.

Results:

Of all variables tested, only antibiotic use within the previous 3 months was found to be an independent risk factor for acquisition of ESBL-EK bacteremia (odds ratio 5.2, 95% confidence interval 1.6–16.9). A greater proportion of patients with non-ESBL-EK bacteremia received appropriate empiric therapy (88% [35/40] versus 15% [6/40], p < 0.001). Time to appropriate therapy was longer for those with ESBL-EK bacteremia (2.42 days versus 0.17 day, p < 0.001). Patient outcomes, including length of stay in hospital, admission to the intensive care unit (ICU), length of stay in the ICU (if applicable), and in-hospital mortality were not affected by the presence of ESBL-EK or the appropriateness of empiric therapy.

Conclusions:

Previous antibiotic use was a significant, independent risk factor for acquiring ESBL-EK. Thus, prior antibiotic use is an important consideration in the selection of empiric antibiotic therapy and should increase the concern for resistant pathogens.     

CaIPF14030 negatively modulates intracellular ATP levels during the development of azole resistance in Candida albicans

Aim:

Widespread and repeated use of azoles, particularly fluconazole, has led to the rapid development of azole resistance in Candida albicans. We investigated the role of CaIPF14030 during the development of azole resistance in C albicans.

Methods:

The expression of CaIPF14030 was measured by quantitative RT-PCR, and CaIPF14030 was disrupted by the hisG-URA3-hisG (URA-blaster) method. The sensitivity of C albicans to azoles was examined using a spot assay, and the intracellular ATP concentrations were measured by a luminometer.

Results:

CaIPF14030 expression in C albicans was up-regulated by Ca²⁺ in a calcineurin-dependent manner, and the protein was overexpressed during the stepwise acquisition of azole resistance. However, disruption or ectopic overexpression of CaIPF14030 did not affect the sensitivity of C albicans to azoles. Finally, we demonstrated that disruption of CaIPF14030 significantly increased intracellular ATP levels, and overexpression significantly decreased intracellular ATP levels in C albicans.

Conclusion:

CaIPF14030 may negatively modulate intracellular ATP levels during the development of azole resistance in C albicans.     

The antimicrobial effects of selenium nanoparticle-enriched probiotics and their fermented broth against Candida albicans

Background

Lactic acid bacteria are considered important probiotics for prevention of some infections. The aim of this work was to investigate the effect of selenium dioxide on the antifungal activity of Lactobacillus plantarum and L. johnsonii against Candida albicans.

Methods

Lactobacillus plantarum and L. johnsonii cells, grown in the presence and absence of selenium dioxide, and their cell-free spent culture media were tested for antifungal activity against C. albicans ATCC 14053 by a hole-plate diffusion method and a time-kill assay.

Results

Both L. plantarum and L. johnsonii reduced selenium dioxide to cell-associated elemental selenium nanoparticles. The cell-free spent culture media, from both Lactobacillus species that had been grown with selenium dioxide for 48 h, showed enhanced antifungal activity against C. albicans. Enhanced antifungal activity of cell biomass against C. albicans was also observed in cultures grown with selenium dioxide.

Conclusions

Selenium dioxide-treated Lactobacillus spp. or their cell-free spent broth inhibited the growth of C. albicans and should be investigated for possible use in anti-Candida probiotic formulations in future.     

Association between BclI polymorphism in the NR3C1 gene and in vitro individual variations in lymphocyte responses to methylprednisolone

AIM

To evaluate the association between the in vitro sensitivity of peripheral blood mononuclear cells (PBMCs) to methylprednisolone (MP) and the presence of genetic polymorphisms involved in glucocorticoid (GC) response.

METHODS

In vitro MP inhibition of the proliferation of lymphocytes stimulated with concanavalin A was determined. Non linear regression of dose–response data was performed computing the MP concentration required to reduce proliferation to 50% (IC₅₀). The maximum inhibition achievable at the highest MP concentration (I_max) was also calculated. Moreover, the Taqman technique was used to analyze the BclI polymorphism in the NR3C1 gene and the Leu155His polymorphism in the NALP1 gene.

RESULTS

A significant association between the BclI mutated genotype and an increased in vitro sensitivity to GCs was observed.

CONCLUSIONS

The a priori evaluation of the BclI polymorphism, associated with a lymphocyte proliferation assay, could represent a useful diagnostic tool for the optimization of steroid treatment.     

No association between LRP5 gene polymorphisms and bone and obesity phenotypes in Chinese male-offspring nuclear families

Aim:

To investigate the effect of low-density lipoprotein receptor-related protein 5 (LRP5) gene polymorphisms on bone and obesity phenotypes in young Chinese men.

Methods:

A total of 1244 subjects from 411 Chinese nuclear families were genotyped by using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique at the Q89R, N740N, and A1330V sites in the LRP5 gene. Bone mineral density (BMD) in the lumbar spine and the hip, total fat mass and total lean mass were measured using dual-energy X-ray absorptiometry. The association between LRP5 gene polymorphisms and peak BMD, body mass index (BMI), total fat mass, total lean mass and percentage of fat mass was assessed using a quantitative transmission disequilibrium test (QTDT).

Results:

No significant within-family associations were found between genotypes or haplotypes of the LRP5 gene and peak BMD, BMI, total fat mass, total lean mass and percentage of fat mass. The 1000 permutations that were subsequently simulated were in agreement with these within-family association results.

Conclusion:

Our results suggest that common polymorphic variations of the LRP5 gene do not influence peak bone mass acquisition and obesity phenotypes in young Chinese men.     

Influence of CYP2B6 and ABCB1 SNPs on nevirapine plasma concentrations in Burundese HIV-positive patients using dried sample spot devices

AIMS

The pharmacokinetics (PK) and pharmacogenetics (PG) of nevirapine have been studied in rich and limited-resource countries. CYP2B6 single nucleotide polymorphisms (SNPs) have been associated with decreased drug clearance. We evaluated the PG determinants of nevirapine trough concentrations in a rural cohort in Burundi using easy to store and transport dried sample spot devices.

METHODS

A cross-sectional analysis in HIV-positive nevirapine-treated patients in Kiremba, north of Burundi, was performed in 2009. After blood withdrawal whole blood was stored on dried blood spots and plasma (after centrifugation) was placed on dried plasma spot devices and stored at room temperature. Nevirapine plasma and dried sample spot concentrations were compared to test the clinical usefulness of this method. SNPs in CYP2B6 and ABCB1 (using a real time PCR technique) were analyzed and associated with nevirapine plasma trough concentrations.

RESULTS

Nevirapine concentrations measured on dried plasma spot devices were highly related to plasma concentrations in 60 patients, although a negative bias was observed (−18%). Nevirapine trough concentrations were above the target concentration (3000 ng ml⁻¹) in 84% of patients and they were associated with CYP2B6 SNPs (both at position 516 and 983). No effect of ABCB1 SNPs was noted.

CONCLUSIONS

Dried plasma spot devices are accurate tools for measuring nevirapine concentrations in rural settings where refrigeration is not available, despite a moderate underestimation bias. They allowed the evaluation of nevirapine concentrations in a cohort of HIV-infected people in rural Burundi, confirming very good exposure and correlation with PG polymorphisms in the CYP2B6 encoding gene.     

Polymorphisms in the HOXD4 gene are not associated with peak bone mineral density in Chinese nuclear families

Aim:

To determine the associations between HOXD4 gene polymorphisms with peak bone mineral density (BMD) throughing measuring three tagging single nucleotide polymorphisms (tagSNPs), including rs1867863, rs13418078, and rs4972504, in HOXD4.

Methods:

Four hundred Chinese nuclear families with male offspring (1215 subjects) and 401 Chinese nuclear families with female offspring (1260 subjects) were recruited. BMD of the lumbar spine 1-4 (L1-4) and left proximal femur including total hip and femoral neck were measured by dual-energy X-ray absorptiometry. The quantitative transmission disequilibrium test (QTDT) was performed to investigate the association among the tagging SNPs, haplotypes and peak BMD.

Results:

Only the CC genotype was identified in rs13418078 in the Chinese population, unlike other populations. We failed to find significant within-family association among these SNPs, haplotypes and peak BMD at any bone site in either male- or female-offspring nuclear families.

Conclusion:

The results suggest that genetic polymorphisms in HOXD4 may not be a major contributor to the observed variability in peak BMD in the lumbar spine and the hip in Chinese men and women.     

Dihydroartemisinin promotes angiogenesis during the early embryonic development of zebrafish

Aim:

To investigate the embryotoxicity of dihydroartemisinin (DHA), the main active metabolite of artemisinin, in zebrafish, and explore the corresponding mechanisms.

Methods:

The embryos of wild type and TG (flk1:GFP) transgenic zebrafish were exposed to DHA. Developmental phenotypes of the embryos were observed. Development of blood vessels was directly observed in living embryos of TG (flk1:GFP) transgenic zebrafish under fluorescence microscope. The expression of angiogenesis marker genes vegfa, flk1, and flt1 in the embryos was detected using real-time PCR and RNA in situ hybridization assays.

Results:

Exposure to DHA (1–10 mg/L) dose-dependently caused abnormal zebrafish embryonic phenotypes in the early developmental stage. Furthermore, exposure to DHA (10 mg/L) resulted in more pronounced embryonic angiogenesis in TG (flk1:GFP) zebrafish line. Exposure to DHA (10 mg/L) significantly increased the mRNA expression of vegfa, flk1, and flt1 in the embryos. Knockdown of the flk1 protein partially blocked the effects of DHA on embryogenesis.

Conclusion:

DHA causes abnormal embryonic phenotypes and promotes angiogenesis in zebrafish early embryonic development, demonstrating the potential embryotoxicity of DHA.     

A cytotoxic hydroperoxy sterol from the brown alga,Nizamuddinia zanardinii

Background

The marine environment is a unique source of bioactive natural products, of which Nizamuddinia zanardinii is an important brown algae distributed in Oman Sea. Literature revealed that there is no report on phytochemistry and pharmacology of this valuable algae.

Methods

Bioguided fractionation of the methanolic extract of Nizamuddinia zanardinii, collected from Oman Sea, led to the isolation of a hydroperoxy sterol. Its structure was determined by analysis of the spectroscopic data as 24-hydroperoxy-24-vinyl cholesterol (HVC). In vitro cytotoxic activity of this compound was evaluated against HT29, MCF7, A549, HepG2 and MDBK cell lines.

Results

Although 24(R)-hydroproxy-24-vinylcholesterol has been previously reported from Sargassum and Padina species, it is the first report on the presence of this compound from N. zanardinii. This compound exhibited cytotoxicity in all cell lines (IC₅₀, 3.62, 9.09, 17.96, 32.31 and 37.31 μg/mL respectively). HVC was also evaluated for apoptotic activity and demonstrated positive results in terminal deoxynucleotidyl transferase dUTP Nick End labeling (TUNEL) assay suggesting it a candidate for further apoptotic studies.

Conclusions

Nizamuddinia zanardinii, a remarkable brown algae of Oman Sea, is a good source of hydroproxy sterols with promising cytotoxic on various cell lines particularly human colon adenocarcinoma.     

Influence of age on frequency of vancomycin dosing

Background:

Vancomycin is commonly prescribed at the authors’ institution because of a high prevalence of invasive infections caused by methicillin-resistant Staphylococcus aureus (MRSA) in a generally younger population. The most commonly prescribed empiric dosing interval is every 12 h (q12h). However, observations have suggested that younger adult patients require more frequent dosing, such as every 8 h (q8h). Initial underdosing of vancomycin may increase the risk of antibiotic failure.

Objective:

To determine whether patients under 40 years of age are more likely than older patients to require q8h dosing of vancomycin and whether recommendations can be made to alter current prescribing practices.

Methods:

This retrospective unmatched case–control study involved patients who had received vancomycin for suspected or confirmed severe MRSA infections. The cases were patients who had been confirmed as requiring q8h dosing, and the controls were patients who had been confirmed as requiring q12h dosing (on the basis of target predose serum levels). The influence of age (the predictor variable) on outcome (the vancomycin regimen) was evaluated by logistic regression.

Results:

The odds ratio for patients under 40 years of age requiring q8h dosing was 3.1 (95% confidence interval 1.5–6.3) (p = 0.002). Sixty percent of patients under 40 ultimately required a q8h regimen to achieve target predose serum levels. Patients who required q8h dosing took longer to achieve their first therapeutic serum level than those with q12h dosing (median 6 versus 4 days; p < 0.001).

Conclusions:

In this patient population, age less than 40 years was a strong predictor for requiring more frequent dosing of vancomycin. The authors suggest that doses of 15 mg/kg IV q8h be used empirically for younger patients with severe infections and normal renal function.     

Artemia salina as a model organism in toxicity assessment of nanoparticles

Background

Because of expanding presence of nanomaterials, there has been an increase in the exposure of humans to nanoparticles that is why nanotoxicology studies are important. A number of studies on the effects of nanomatrials in in vitro and in vivo systems have been published. Currently cytotoxicity of different nanoparticles is assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on different cell lines to determine cell viability, a tedious and expensive method. The aim of this study was to evaluate the Artemia salina test in comparison with the MTT assay in the assessment of cytotoxicity of nanostructures because the former method is more rapid and convenient and less expensive.

Methods

At the first stage, toxicity of different nanoparticles with different concentrations (1.56–400 μg/mL) was measured by means of the brine shrimp lethality test. At the second stage, the effect of nanoparticles on the viability of the L929 cell line was assessed using the MTT assay. Experiments were conducted with each concentration in triplicate.

Results

The results obtained from both tests (A. salina test and MTT assay) did not have statistically significant differences (P > 0.05).

Conclusions

These findings suggest that the A. salina test may expedite toxicity experiments and decrease costs, and therefore, may be considered an alternative to the in vitro cell culture assay.     

Effectiveness of three times daily lansoprazole/amoxicillin dual therapy for Helicobacter pylori infection in Korea

AIM

We compared three times daily dual therapy with standard triple therapy for effectiveness and safety in H. pylori infection.

METHODS

Two hundred and four H. pylori positive patients with peptic ulcer were randomly assigned to one of two regimens: (i) triple therapy with amoxicillin, clarithromycin and lansoprazole twice daily for 2 weeks or (ii) dual therapy with amoxicillin and lansoprazole three times daily for 2 weeks. The success of eradication was evaluated 4 to 5 weeks after completing treatment.

RESULTS

The eradication rate was 82.8% in the triple therapy group and 78.4% in the dual therapy group by per protocol analysis. This difference was not significant (P= 0.573). Adverse events were more frequent in the triple therapy group than in the dual therapy group (P= 0.002).

CONCLUSIONS

Because dual therapy had fewer side effects than triple therapy and a similar eradication rate, dual therapy may provide an acceptable alternative first line therapy for H. pylori eradication in Korea.     

Transport and pharmacodynamics of albitiazolium, an antimalarial drug candidate

BACKGROUND AND PURPOSE

Choline analogues, a new type of antimalarials, exert potent in vitro and in vivo antimalarial activity. This has given rise to albitiazolium, which is currently in phase II clinical trials to cure severe malaria. Here we dissected its mechanism of action step by step from choline entry into the infected erythrocyte to its effect on phosphatidylcholine (PC) biosynthesis.

EXPERIMENTAL APPROACH

We biochemically unravelled the transport and enzymatic steps that mediate de novo synthesis of PC and elucidated how albitiazolium enters the intracellular parasites and affects the PC biosynthesis.

KEY RESULTS

Choline entry into Plasmodium falciparum-infected erythrocytes is achieved both by the remnant erythrocyte choline carrier and by parasite-induced new permeability pathways (NPP), while parasite entry involves a poly-specific cation transporter. Albitiazolium specifically prevented choline incorporation into its end-product PC, and its antimalarial activity was strongly antagonized by choline. Albitiazolium entered the infected erythrocyte mainly via a furosemide-sensitive NPP and was transported into the parasite by a poly-specific cation carrier. Albitiazolium competitively inhibited choline entry via the parasite-derived cation transporter and also, at a much higher concentration, affected each of the three enzymes conducting de novo synthesis of PC.

CONCLUSIONS AND IMPLICATIONS

Inhibition of choline entry into the parasite appears to be the primary mechanism by which albitiazolium exerts its potent antimalarial effect. However, the pharmacological response to albitiazolium involves molecular interactions with different steps of the de novo PC biosynthesis pathway, which would help to delay the development of resistance to this drug.     

Tetramethylphenylenediamine protects the isolated heart against ischaemia-induced apoptosis and reperfusion-induced necrosis

BACKGROUND AND PURPOSE

Cytochrome c when released from mitochondria into cytosol triggers assembly of the apoptosome resulting in caspase activation. Recent evidence suggests that reduced cytochrome c is unable to activate the caspase cascade. In this study, we investigated whether a chemical reductant of cytochrome c, N,N,N′,N′-tetramethylphenylene-1,4-diamine (TMPD), which we have previously shown to block cytochrome c-induced caspase activation, could prevent ischaemia-induced apoptosis in the rat perfused heart.

EXPERIMENTAL APPROACH

The Langendorff-perfused rat hearts were pretreated with TMPD and subjected to stop-flow ischaemia or ischaemia/reperfusion. The activation of caspases (measured as DEVD-p-nitroanilide-cleaving activity), nuclear apoptosis of cardiomyocytes (measured by dUTP nick end labelling assay), mitochondrial and cytosolic levels of cytochrome c (measured spectrophotometrically and by elisa), and reperfusion-induced necrosis (measured as the activity of creatine kinase released into perfusate) were assessed.

KEY RESULTS

We found that perfusion of the hearts with TMPD strongly inhibited ischaemia- or ischaemia/reperfusion-induced activation of caspases and partially prevented nuclear apoptosis in cardiomyocytes. TMPD did not prevent ischaemia- or ischaemia/reperfusion-induced release of cytochrome c from mitochondria into cytosol. TMPD also inhibited ischaemia/reperfusion-induced necrosis.

CONCLUSIONS AND IMPLICATIONS

These results suggest that TMPD or related molecules might be used to protect the heart against damage induced by ischaemia/reperfusion. The mechanism of this protective effect of TMPD probably involves electron reduction of cytochrome c (without decreasing its release) which then inhibits the activation of caspases.     

Bcl-2-dependent upregulation of autophagy by sequestosome 1/p62 in vitro

Aim:

To investigate whether sequestosome 1/p62 (p62), a key cargo adaptor protein involved in both the ubiquitin-proteasome system and the autophagy-lysosome system, could directly regulate autophagy in vitro.

Methods:

HEK 293 cells or HeLa cells were transfected with p62-expressing plasmids or siRNA targeting p62. The cells or the cell lysates were subsequently subjected to immunofluorescence assay, immunoprecipitation assay, or immunoblot analysis. In vitro pulldown assay was used to study the interaction of p62 with Bcl-2.

Results:

Overexpression of p62 significantly increased the basal level of autophagy in both HEK 293 cells and HeLa cells, whereas knockdown of p62 significantly decreased the basal level of autophagy. In vitro pulldown assay showed that p62 directly interacted with Bcl-2. It was observed in HeLa cells that p62 co-localized with Bcl-2. Furthermore, knockdown of p62 in HEK 293 cells significantly increased the amount of Beclin 1 that co-immunoprecipitated with Bcl-2.

Conclusion:

p62 induces autophagy by disrupting the association between Bcl-2 and Beclin 1.     

Development of a validated HPLC method for the simultaneous determination of flavonoids in Cuscuta chinensis Lam. by ultra-violet detection

Background

Cuscuta species known as dodder, have been used in traditional medicine of eastern and southern Asian countries as liver and kidney tonic. Flavonoids are considered as the main biologically active constituents in Cuscuta plants especially in C. chinensis Lam.

Objective

In the present study, a fast, simple and reliable method for the simultaneous determination and quantization of C. chinensis flavonols including hyperoside, rutin, isorhamnetin and kaempferol has been developed.

Materials and methods

The chromatographic separation was carried out on a reversed phase ACE 5 C₁₈ with eluting at a flow rate of 1 ml/min using a gradient with O-phosphoric acid 0.25% : acetonitrile for 42 min. UV spectra were collected across the range of 200–900 nm, extracting 360 nm for the chromatograms. The method was validated according to linearity, selectivity, precision, recovery, LOD and LOQ.

Results

The method was selective for determination of rutin, hyperoside, isorhamnetin and kampferol. The calibration graphs of flavonols were linear with r² > 0.999. RSDs% of intra- and inter-day precisions were found 1.3&3.4 for rutin, 1.5&2.8 for hyperoside, 1.3&3.3 for isorhamnetin and 1.7 & 2.9 for kaempferol which were satisfactory. LODs and LOQs were calculated as 1.73 & 8.19 for rutin, 0.09 & 4.19 for hyperoside, 2.09 & 6.3 for isorhamnetin and 0.18 & 0.56 for kaempferol. The recovery averages of above-mentioned flavonols were 90.3%, 97.4%, 98.7% and 90.0%, respectively.

Conclusion

The simplicity of the method makes it highly valuable for quality control of C. chinensis according to quantization of flavonols.