Safety assessment of selected medicinal food plants used in Ayurveda through CYP450 enzyme inhibition study.

BACKGROUND: Andrographis paniculata, Bacopa monnieri and Centella asiatica are mentioned in Ayurveda for the management of neurodegenerative disorders. These plants and their phytomolecules, such as andrographolide, bacoside A and asiaticoside, were studied for their inhibition potential on pooled CYP450 as well as human CYP3A4, CYP2D6, CYP2C9 and CYP1A2 by CYP-CO complex assay and fluorogenic assay respectively followed by IC50 determination. Quantification of bioactive compounds present in the extracts was done by RP-HPLC. Heavy metal content in the selected medicinal plants was determined by atomic absorption spectroscopy. RESULT: CYP-CO complex assay indicated significantly less inhibition potential than standard inhibitor (P < 0.05 and above). A. paniculata showed highest inhibitory activity against CYP3A4 and CYP2D6 (IC50 = 63.06 ± 1.35 µg mL-1 ; 88.80 ± 3.32 µg mL-1 ), whereas C. asiatica and B. monnieri showed least inhibitory activity against CYP1A2 (IC50 = 288.83 ± 1.61 µg mL-1 ) and CYP2C9 (184.68 ± 3.79 µg mL-1 ), respectively. In all cases the extract showed higher inhibition than the single bioactive compounds. The heavy metals content in the plant extracts were within the permissible limits. CONCLUSION: The findings suggested that selected food plants and bioactive compounds contributed negligible interaction potential with CYP isozymes and may not possess any harmful effect with regard to their therapeutic application. © 2016 Society of Chemical Industry.

Interaction potential of Trigonella foenum graceum through cytochrome P450 mediated inhibition.

OBJECTIVE: The seeds of Trigonella foenum-graecum (TFG) (family: Leguminosae) are widely consumed both as a spice in food and Traditional Medicine in India. The present study was undertaken to evaluate the inhibitory effect of standardized extract of TFG and its major constituent trigonelline (TG) on rat liver microsome (RLM) and cytochrome P450 (CYP450) drug metabolizing isozymes (CYP3A4 and CYP2D6), which may indicate the possibility of a probable unwanted interaction. MATERIALS AND METHODS: Reverse phase-high performance liquid chromatography method was developed to standardize the hydroalcoholic seed extract with standard TG. The inhibitory potential of the extract and TG was evaluated on RLM and CYP isozymes using CYP450-carbon monoxide (CYP450-CO) complex assay and fluorescence assay, respectively. RESULTS: The content of TG in TFG was found to be 3.38% (w/w). The CYP-CO complex assay showed 23.32% inhibition on RLM. Fluorescence study revealed that the extract and the biomarker had some inhibition on CYP450 isozymes e.g. CYP3A4 and CYP2D6 (IC50 values of the extract: 102.65 ± 2.63-142.23 ± 2.61 µg/ml and TG: 168.73 ± 4.03-180.90 ± 2.49 µg/ml) which was very less compared to positive controls ketoconazole and quinidine. Inhibition potential of TFG was little higher than TG but very less compared to positive controls. CONCLUSIONS: From the present study, we may conclude that the TFG or TG has very less potential to inhibit the CYP isozymes (CYP3A4, CYP2D6), so administration of this plant extract or its biomarker TG may be safe.

Cytochrome P450 inhibitory potential and RP-HPLC standardization of trikatu--a Rasayana from Indian Ayurveda.

ETHNOPHARMACOLOGICAL RELEVANCE: Trikatu is a very well known 'Rasayana' in Ayurveda and widely used as a polyherbal ayurvedic formulation in India. It consists of three well known plants, viz., Piper longum (PL), Piper nigrum (PN) and Zingiber officinale (ZO) in equal ratio. Trikatu has been prescribed for cough, cold, fever, asthma, respiratory problems and improvement of digestive disorders. The aim of the present study was to investigate the effect of individual ingredients of trikatu namely PL, PN, and ZO and formulations [Marketed formulation (MF) and laboratory formulation (LF)] on drug metabolizing enzymes (CYP3A4 and CYP2D6), to assess its herb-drug interaction potential through cytochrome P450 inhibition assays. Further this work was aimed to develop an RP-HPLC method for the identification and quantification of piperine and 6-gingerol in the crude drug trikatu. MATERIALS AND METHODS: Enzyme inhibition effect of LF, MF, PL, PN and ZO was explored through CYP450-CO complex assay using rat liver microsomes (RLM) and a fluorescence screening method using individual isoenzymes (CYP3A4 and CYP2D6). The RP-HPLC method was developed for the identification and quantification of piperine and 6-gingerol in LF, MF and individual plant materials at the concentration of 1mg/mL. RESULTS: RP-HPLC analysis confirmed the presence of piperine and 6-gingerol in LF and MF [Piperine: 7.89±2.12% (w/w) (MF), 6.70±2.13% (w/w) (LF)]; [6-gingerol: 5.3±1.21% (w/w) (MF), 4.95±2.34% (w/w) (LF)]. Inhibitory potential of MF and LF in CYP450-CO complex assay was found to be 37.54±3.12% (MF) and 35.12±2.31% (LF) and against CYP2D6 and CYP3A4 was estimated to be IC50 251.30±3.98 and 245.23±1.92µg/mL and IC50 225.50±1.02 and 223.254±0.92µg/mL respectively. CONCLUSIONS: Different concentrations of the trikatu formulation and its individual components showed significantly (p<0.001) less inhibitory activity on individual isoenzymes as compared to the positive control. The crude drug exhibited inhibitory potential against the CYP450 enzymes in a concentration dependent manner. Outcome of the present study demonstrated that trikatu has less interaction potential with drug metabolizing enzymes.

Best combination of promoter and micellar catalyst for the rapid conversion of sorbitol to glucose.

Kinetic data for oxidation of D-sorbitol to glucose by hexavalent chromium in aqueous medium and aqueous surfactant medium (SDS, TX-100) have been reported. Effect of promoter such as PA, bipy and phenanthroline on the reaction has been investigated. The reaction is performed under pseudo first order condition with an excess of substrate over the oxidant. The reaction is first order with respect to substrate and oxidant. The micelles have a catalytic effect on the reaction. Combination of phen and TX-100 produces almost twelve times increase in rate of oxidation.

Combination of best promoter and micellar catalyst for more than kilo-fold rate acceleration in favor of chromic acid oxidation of D-galactose to D-galactonic acid in aqueous media at room temperature.

Picolinic acid, 2,2'-bipyridine and 1,10-phenanthroline promoted Cr(VI) oxidation of D-galactose to D-galactonic acid in three representative aqueous micellar media has been studied. The anionic surfactant (SDS) accelerated the rate of reaction while the cationic surfactant (CPC) and neutral surfactant (TX-100) retarded the reaction rate. Combination of bipy and SDS is the best choice for chromic acid oxidation of D-galactose to D-galactonic acid in aqueous media although 1,10-phenanthroline is best promoter in absence of micellar catalyst.

Suitable combination of promoter and micellar catalyst for kilo fold rate acceleration on benzaldehyde to benzoic acid conversion in aqueous media at room temperature: a kinetic approach.

The kinetics of oxidation of benzaldehyde by chromic acid in aqueous and aqueous surfactant (sodium dodecyl sulfate, SDS, alkyl phenyl polyethylene glycol, Triton X-100 and N-cetylpyridinium chloride, CPC) media have been investigated in the presence of promoter at 303 K. The pseudo-first-order rate constants (kobs) were determined from a logarithmic plot of absorbance as a function time. The rate constants were found to increase with introduction of heteroaromatic nitrogen base promoters such as Picolinic acid (PA), 2,2'-bipyridine (bipy) and 1,10-phenanthroline (phen). The product benzoic acid has been characterized by conventional melting point experiment, NMR, HRMS and FTIR spectral analysis. The mechanism of both unpromoted and promoted reaction path has been proposed for the reaction. In presence of the anionic surfactant SDS, cationic surfactant CPC and neutral surfactant TX-100 the reaction can undergo simultaneously in both aqueous and micellar phase with an enhanced rate of oxidation in the micellar phase. Both SDS and TX-100 produce normal micellar effect whereas CPC produce reverse micellar effect in the presence of benzaldehyde. The observed net enhancement of rate effects has been explained by considering the hydrophobic and electrostatic interaction between the surfactants and reactants. SDS and bipy combination is the suitable one for benzaldehyde oxidation.

Efficient combination of promoter and catalyst for chromic acid oxidation of propan-2-ol to acetone in aqueous acid media at room temperature.

Oxidation of propan-2-ol to acetone was carried out in aqueous media at room temperature. The effect of promoter (PA, bpy, phen), micellar catalyst (SDS, CPC, TX-100) and their combination has been studied. The reactions were performed under the condition [Propan-2-ol]T≫[Cr(VI)]T at 30°C. Then kobs and half life of all the reaction were determined to identify which promoter and which combination are the most effective for this oxidation. Among the promoters phen accelerates the reaction most in aqueous media. In absence of promoters anionic surfactant SDS increases the rate more effectively than neutral surfactant TX-100. CPC retards the rate in comparison to aqueous media. The rate of the oxidation is highest in presence of the combination of bpy and SDS.

Botanicals as medicinal food and their effects on drug metabolizing enzymes.

Botanicals fall under different regulations in different countries and are mostly consumed without the consultation of the healthcare professional. Over the last decade, utilization of herbal therapies has been extensively documented. The findings indicate the possibility of potential herb-drug interactions due to the concomitant administration of herbal extracts and prescription/over-the-counter drugs. Simultaneously, with the increasing public awareness and search for safer herbal remedies, the study on herbal-drug interactions has gained momentum through the study of drug metabolizing enzymes. Cytochrome P450 (CYP) inhibition or induction is probably the most common mechanism for the pharmacokinetic interactions of herbs and drugs. Any inhibition of CYP enzymes by herbal extracts may result in enhanced plasma and tissue concentration of drugs, leading to toxicity, while induction results in reduced drug concentration leading to decreased drug efficacy and treatment failure. Considering the rapidly growing herbal markets, these types of clinical interactions remain under-reported and unclear. With the increasing consumption of herbal extracts along with prescription medicines, the safety of herbs has become a concern. This article reviews the potential for drug interactions by herbal extracts through drug metabolizing enzymes.

Enhancing bioavailability and hepatoprotective activity of andrographolide from Andrographis paniculata, a well-known medicinal food, through its herbosome.

BACKGROUND: Andrographis paniculata is a health food used extensively in Southeast Asia, India and China and contains the pharmacologically important phytochemical andrographolide. Although andrographolide has antihepatotoxic activity, its bioavailability from A. paniculata is restricted by its rapid clearance and high plasma protein binding. The aim of this study was to formulate a herbosome of andrographolide with a naturally occurring phospholipid in order to enhance the bioavailability and hepatoprotective activity of andrographolide in rats. RESULTS: Andrographolide herbosome equivalent to 25 and 50 mg kg(-1) andrographolide significantly protected the liver of rats, restoring hepatic enzyme activities with respect to carbon tetrachloride-treated animals (P < 0.05 and P < 0.01 respectively). The rat plasma concentration of andrographolide obtained from the complex equivalent to 25 mg kg(-1) andrographolide (C(max) = 9.64 microg mL(-1)) was higher than that obtained from 25 mg kg(-1) andrographolide (C(max) = 6.79 microg mL(-1)), and the complex maintained its effective plasma concentration for a longer period of time. CONCLUSION: The results proved that the andrographolide complex produced by this method has better bioavailability and hence improved hepatoprotective activity compared with andrographolide at the same dose. Andrographolide complexation is therefore helpful in solving the problem of rapid clearance and low elimination half-life associated with andrographolide from A. paniculata.

Exploring the effect of Hesperetin-HSPC complex--a novel drug delivery system on the in vitro release, therapeutic efficacy and pharmacokinetics.

Hesperetin is known to exhibit a variety of pharmacological activities in mammalian cell systems. Although it shows appreciable bioavailability when administered orally, its faster elimination from body creates the need of frequent administration to maintain effective plasma concentration. To overcome this limitation, a phospholipid complex of hesperetin was prepared and evaluated for antioxidant activity and pharmacokinetic profile. The hesperetin content of the complex was determined by a spectrophotometer and the surface characteristics of the complex were studied by means of microscope. The antioxidant activity was evaluated in carbon-tetrachloride-intoxicated rats at a dose level of 100 mg/kg body weight, p.o. The complex was studied for in vitro drug release characteristics and effect of complexation on serum concentration of hesperetin in rats was also studied along with main pharmacokinetic parameters. The results showed that the complex has a sustained release property and enhanced antioxidant activity (P < 0.05 and <0.01) as compared to free hesperetin at the same dose level. Pharmacokinetic study depicted that the complex has higher relative bioavailability and acted for a longer period of time. The study therefore suggests that phospholipid complex of hesperetin produced better antioxidant activity than free drug at the same dose level and the effect persisted for a longer period of time, which may be helpful in solving the problems of faster elimination of the molecule.

Enhanced oral bioavailability and antioxidant profile of ellagic acid by phospholipids.

Ellagic acid (EA) has been reported as a potent antioxidant from natural resources with several nutritional benefits. The major disadvantage of this phytoconstituent is its rapid elimination from the body after administration. To overcome this limitation, a novel dietary formulation of EA with phospholipid was developed to investigate the effect of this complex on carbon tetrachloride induced liver damage in rats. The antioxidant activity of the complex (equivalent of EA = 25 and 50 mg/kg of body weight) and free EA (25 and 50 mg/kg of body weight) was evaluated by measuring various enzymes in oxidative stress condition. The complex significantly protected the liver by restoring the activity of superoxide dismutase, catalase and liver glutathione, and thiobarbituric acid reactive substances with respect to the carbon tetrachloride treated group (P < 0.05 and < 0.01). The complex provided better protection to rat liver than free EA at the same dose. The serum concentration of EA obtained from the complex (equivalent to 80 mg/kg of EA) was higher (C(max) = 0.54 microg/mL) than that of pure EA (80 mg/kg) (C(max) = 0.21 microg/mL), and the complex maintained effective concentration for a longer period of time in serum. The experimental outcome highlighted better hepatoprotective activity of the EA complex due to its potential antioxidant property compared with the free EA tested at the same dose level.

Validation of HPTLC method for the analysis of taraxerol in Clitoria ternatea.

A new, simple, sensitive, selective and precise HPTLC method has been developed for the determination of taraxerol in Clitoria ternatea L. Determination of taraxerol was performed on TLC aluminium plates. Linear ascending development was carried out in twin trough glass chamber saturated with hexane and ethyl acetate (80:20 v/v). The plate was then dried and sprayed with anisaldehyde reagent. A Camag TLC scanner III was used for spectrodensitometric scanning and analysis at 420 nm. The system was found to give compact spots for taraxerol (R(f) 0.53). The calibration plot was linear in the range of 100-1200 ng of taraxerol. The correlation coefficient of 0.9961 was indicative of good linear dependence of peak area on concentration. The concentration of taraxerol was found to be 12.4 mg/g w/w in the hydroalcoholic extract of C. ternatea root. To study the accuracy and precision of the method, recovery studies were performed. Recovery values from 99.65 to 99.74% showed excellent reliability and reproducibility of the method. The limits of detection and quantification were determined to be 31 and 105 ng/spot, respectively. The proposed HPTLC method for quantitative monitoring of taraxerol in C. ternatea can be used for routine quality testing of C. ternatea extract used in Ayurvedic formulations.

Regulation of extracellular calcium in the hippocampus in vivo during epileptiform activity--role of astrocytes.

Astrocytes have been suggested to regulate the extracellular calcium concentration ([Ca(2+)](o)), but this has not been thoroughly investigated. Adult, male Sprague-Dawley rats were used to record changes in [Ca(2+)](o) in the hippocampus during epileptiform activity. Maximal decreases in [Ca(2+)](o) in CA1 were measured in the pyramidal cell layer during 20 Hz, 20s stimulus trains to the contralateral CA3 region. Maximal decreases in [Ca(2+)](o) in the dentate gyrus were measured when maximal dentate activation had appeared-irrespective of the location, frequency or duration of the stimulation. Maximal decreases were 36% greater in the dentate gyrus than in CA1. During prolonged discharges, [Ca(2+)](o) recovered partially towards the baseline in both hippocampal regions. To investigate the role of astrocytes, local injections of fluorocitrate (FC), a metabolic toxin selectively taken up by astrocytes, were used. FC (0.1, 0.25 or 0.5mM FC), but not vehicle (2 microl), caused a small, but significant decrease in the maximal changes in CA1, but an increase in the dentate gyrus. The results suggest that maximal decreases in [Ca(2+)](o) occur in the hippocampus in response to burst firing of neurons and that astrocytes play a minimal role in the regulation of [Ca(2+)](o) during epileptiform activity.

Protective effect of biflavones from Araucaria bidwillii Hook in rat cerebral ischemia/reperfusion induced oxidative stress.

Oxidative stress is implicated in the pathogenesis of ischemic brain injury. Flavonoids from various herbal extracts have been shown to be neuroprotective in experimental models of cerebral ischemia/reperfusion (I/R). The present study was designed to investigate the neuroprotective effect of the biflavone rich fraction from Araucaria bidwillii Hook (ABH) (Family: Araucariaceae) in I/R induced oxidative stress. The I/R was induced by occluding bilateral common carotid arteries (BCCAO) for 30 min, followed by 24 h reperfusion. BCCAO caused significant depletion in superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and significant increase in lipid peroxidation (LPO) in various brain regions. The neurological deficit and sensory motor function were also decreased significantly by BCCAO group as compared to sham group animals. All the alteration induced by cerebral ischemia was significantly attenuated by 7 days' pretreatment with biflavone fraction (BFR) at the dose of 100 and 200 mg/kg, comparable to that given by Vitamin E (200 mg/kg). Consistent with neurobehavioral deficits, pretreatment with biflavones at higher doses significantly reduced ischemia-induced neuronal loss of the brain. In conclusion the biflavone rich fraction from A. bidwillii was found to protect rat brain against I/R induced oxidative stress, and attributable to its antioxidant properties.

Plants of Indian origin in drug discovery.

The Indian system of medicine (ISM) consists of several major components such as Ayurveda, Siddha, Unani and homeopathy. All these components provide the major healthcare for a large part of the population in India and have been flourishing in this country for many centuries. Medicinal plants constitute a major part in all of these traditional systems. Several regulations and controls on the use of medicinal plants in traditional medicine have evolved. On the one hand, such regulations will help to cure different aliments through Indian indigenous resources and, on the other hand, they will help in the screening and evaluation of natural resources through the development of potential lead components in order to provide better healthcare through ISM. Several lead molecules have been developed from ISM. This review aims at highlighting aspects of drug development from Indian medicinal plants through the use of ethnobotany, ethnopharmacology and systems biology, with different approaches using metabolomics and allied fields.

Curcumin-phospholipid complex: Preparation, therapeutic evaluation and pharmacokinetic study in rats.

A novel formulation of curcumin in combination with the phospholipids was developed to overcome the limitation of absorption and to investigate the protective effect of curcumin-phospholipid complex on carbon tetrachloride induced acute liver damage in rats. The antioxidant activity of curcumin-phospholipid complex (equivalent of curcumin 100 and 200 mg/kg body weight) and free curcumin (100 and 200 mg/kg body weight) was evaluated by measuring various enzymes in oxidative stress condition. Curcumin-phospholipid complex significantly protected the liver by restoring the enzyme levels of liver glutathione system and that of superoxide dismutase, catalase and thiobarbituric acid reactive substances with respect to carbon tetrachloride treated group (P < 0.05 and <0.01). The complex provided better protection to rat liver than free curcumin at same doses. Serum concentration of curcumin obtained from the complex (equivalent to 1.0 g/kg of curcumin) was higher (Cmax 1.2 microg/ml) than pure curcumin (1.0 g/kg) (Cmax 0.5 microg/ml) and the complex maintained effective concentration of curcumin for a longer period of time in rat serum. The result proved that curcumin-phospholipid complex has better hepatoprotective activity, owe to its superior antioxidant property, than free curcumin at the same dose level.

Substance P is responsible for physiological alterations such as increased chloride ion secretion and glucose malabsorption in cryptosporidiosis.

Cryptosporidiosis, caused by the protozoan parasite Cryptosporidium, causes self-limited diarrhea in immunocompetent hosts and severe life-threatening diarrhea in AIDS patients. Highly active antiretroviral therapy has been used to effectively treat cryptosporiosis in some but not all AIDS patients. Therefore, there is an urgent need for innovative drugs to treat this disease. Cryptosporidium infection results in intestinal pathophysiological changes such as glucose malabsorption, increased chloride ion (Cl(-)) secretion, and epithelial barrier disruption, leading to disease pathogenesis. In order to develop tools to combat this opportunistic pathogen, it is vital to understand mediators involved in disease pathogenesis. Substance P (SP), a neuropeptide and pain transmitter, is located in the gastrointestinal tract. SP can cause Cl(-) secretion in human gastrointestinal explants. However, its role in cryptosporidiosis has not been fully studied. Jejunal samples from macaques before and after Cryptosporidium parvum infection were assayed for SP and SP receptor mRNA and protein levels by reverse transcription-PCR and by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. The role of SP in pathophysiological alterations, such as Cl(-) secretion and glucose malabsorption, was studied using tissues derived from macaques infected with C. parvum by the Ussing chamber technique. SP and SP receptor mRNA and protein expression levels were increased in jejunal samples following C. parvum infection and were accompanied by increased basal ion secretion and glucose malabsorption. In vitro treatment of samples obtained from infected macaques with the SP receptor antagonist aprepitant (Emend; Merck, Whitehouse Station, NJ) completely reversed the increase in basal ion secretion and corrected the glucose malabsorption. Our findings raise the possibility of using SP receptor antagonists for the treatment of symptoms associated with cryptosporidiosis.

Antioxidant effect of Cytisus scoparius against carbon tetrachloride treated liver injury in rats.

The study was aimed to investigate the antioxidant activity of Cytisus scoparius L. (Family: Leguminosae) on CCl(4) (carbon tetrachloride) treated oxidative stress in Wistar albino rats. CCl(4) injection induced oxidative stress by a significant rise in serum glutamate oxaloacetate transaminases (SGOT), serum glutamate pyruvate transaminases (SGPT), lactate dehydrogenase (LDH) and thiobarbituric acid reactive substances (TBARS) along with reduction of superoxide dismutase (SOD), catalase (CAT), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione-s-transferase (GST) and glutathione reductase (GRD). Pretreatment of rats with different doses of plant extract (250 and 500mg/kg) significantly lowered SGOT, SGPT, LDH and TBARS levels against CCl(4) treated rats. GSH and hepatic enzymes like SOD, CAT, GPx, GRD, and GST were significantly increased by treatment with the plant extract, against CCl(4) treated rats. The activity of extract at the dose of 500mg/kg was comparable to the standard drug, silymarin (25mg/kg). Based on these results, it was observed that Cytisus scoparius extract protects liver from oxidative stress induced by CCl(4) in rats and thus helps in evaluation of the traditional claim on this plant.

Determination of 6-gingerol in ginger (Zingiber officinale) using high-performance thin-layer chromatography.

A sensitive and accurate High-Performance TLC (HPTLC) method has been developed to determine the quantity of 6-gingerol in rhizomes of Zingiber officinale (family: Zingiberaceae), commonly known as ginger. Methanol extracts of rhizomes from three different sources were used for HPTLC, n-hexane, and diethyl ether (40:60 v/v) as the mobile phase. The Rf of 6-gingerol was found to be 0.40. The calibration plot was linear in the range of 250-1200 ng of 6-gingerol and the correlation coefficient of 0.9997 was indicative of good linear dependence of peak area on concentration. The mean quantity of 6-gingerol was found to be 60.44+/-2.53 mg/g of ginger extract. The method permits reliable quantification of 6-gingerol and good resolution and separation of 6-gingerol from other constituents of ginger. To study the accuracy and precision of the method, recovery studies were performed by the method of standard addition. Recovery values from 99.79 to 99.84% showed the excellent reliability and reproducibility of the method. The proposed HPTLC method for quantitative monitoring of 6-gingerol in ginger can be used for routine quality testing of ginger extracts.

Enhanced therapeutic potential of naringenin-phospholipid complex in rats.

Naringenin is a naturally occurring flavanone, possessing a variety of biological activity. Due to its rapid elimination, naringenin needs frequent administration to maintain an effective plasma concentration. We have evaluated the therapeutic potential of naringenin-phospholipid complex under oxidative stress conditions compared with free naringenin. Naringenin-phospholipid complex was prepared and assessed for antioxidant activity in carbon tetrachloride intoxicated rats at a dose level of 100 mg kg-1 (p.o.). Liver function tests were studied by assessing serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, serum alkaline phosphatase and total bilirubin. Marker enzymes of liver, namely glutathione peroxidase, superoxide dismutase, catalase and thiobarbituric acid reactive substances, were measured to evaluate the antioxidant potential at the same dose level. The plasma concentration of naringenin was also measured. It was observed that the naringenin-phospholipid complex enhanced the antioxidant activity of the biomolecule and protected the liver significantly for a longer time as compared with free naringenin at the same dose level. Phospholipid complex of naringenin produced better antioxidant activity than the free compound with a prolonged duration of action, which may be helpful in reducing the fast elimination of the molecule from body.