Showing papers in "Acta pharmaceutica Sinica in 1997"

Effects of neferine on platelet aggregation in rabbits

Abstract: Neferine (Nef), a hypotensive agent with antiarrythmic action, is a dibenzyl isoquinoline alkaloid isolated from a Chinese medicinal herb( Nelumbo nucifera Gaertn). Its effects on platelet aggregation and TXA 2/PGI 2 and cAMP/cGMP balance were studied with methods of turbidimetry and RIA. Nef was shown to significantly inhibit rabbit platelet aggregation induced by ADP, collagen, arachidonic acid (AA) and platelet-activating factor(PAF) with IC 50 of 16, 22, 193 and 103 μmol·L -1 , respectively. Nef was found to increase vascular 6 keto PGF 1α and platelet cAMP levels in dose dependent manner, but inhibit AA stimulated TXA 2 release from platelets. Nef showed no significant effect on the platelet cGMP level. The results suggest that the mechanism of Nef on platelet aggregation is related to regulation of TXA 2/PGI 2 and cAMP/cGMP balance.

[Studies on nimodipine sustained-release tablet capable of floating on gastric fluid with prolonged gastric resident time].

Abstract: Nimodipine was incorporated into poloxamer 188 solid dispersion before formulation, then mixed excipient and solid dispersion were directly compressed into nimodipine floating sustained release tablet(NM FSRT). Formulations were optimized using uniform design and variables affecting nimodipine release from matrix were studied. Preliminary in vivo evaluation was carried out in healthy volunteers. Results showed that the optimized formulation could remain floating on gastric fluid for over 10 hours. In vitro release(0 15～6 h) conformed to zero order kinetics. Hydroxypropylmethylcellulose(HPMC) and polyethylene glycol 6000(PEG 6000) showed the biggest effect on in vitro drug release. Increasing HPMC content and decreasing PEG 6000 content led to decrease of nimodipine release in vitro . NM FSRT did remain floating on gastric fluid with prolonged gastric resident time(GRT) of 5 hours under fed condition, while GRT was only 3 hours under fasted condition. GRT of nimodipine conventional tablet(NM CT) under fed and fasted conditions was 3 and 2 hours, respectively. Relative bioavailability of NM FSRT was 391 46% and MRT was over twice that of NM CT. NM FSRT appeared to have prolonged GRT and improved bioavailability.

Comparative molecular field analysis (CoMFA) of allylamine antimycotics

Abstract: Active analog approach has been applied to determine the pharmacophoric conformations of the allylamine antimycotics. Comparative molecular field analysis (CoMFA) has been used to establish 3D QSAR of 48 allylamine antimycotics against six common human pathogenic fungi. Two different alignment rules were compared in the meantime. Five new synthetic compounds have been successfully employed to examine the predictive abilities of the CoMFA models against Trichophyton mentagrophytes and Asperigillus fumigatus .

Regulation of water channel gene (AQP-CHIP) expression by estradiol and anordiol in rat uterus.

Abstract: In the present studies, we observed the regulation of water channel gene (AQP-CHIP) expression by estradiol (E2) and anordiol, an antiestrogen with agonist activity, in immature female rat uterus. Antisense and sense oligonucleotide primers corresponding to the consensus sequences of two rats AQP-CHIP water channels were synthesized and used to amplify a cDNA fragment that was reverse-transcripted from rat uterine total RNA preparation. E2 administered as a single dose of 40 micrograms.kg-1 to immature female rats induced a significant increase in AQP-CHIP mRNA expression 9 h after treatment. The lowest effective doses of E2 and anordiol were 40 and 50 micrograms.kg-1, respectively. The stimulatory effect of anordiol was more pronounced than that of E2. The present results suggest that AQP-CHIP water channel gene expression may be involved in E2- and anordiol-mediated water imbibition and luminal fluid production in the uterus.

The immunomodulatory effect of Achyranthes bidentata polysaccharides

Abstract: Achyranthes bidentata polysaccharides(ABPS) was extracted from the root of Achyranthes bidentata Blume with molecular weight of 1400. It composed of fructose and glucose residues. The molar ratio was 8.7:1.0. It was a water-soluble neutral polysaccharide of white powder in purity of 99.9%. The effect of ABPS 0.625 x 10(2)-2.00 x 10(3) mg.L-1 on lymphocyte proliferation to Con A on splenocytes from aged mice was evaluated to be about 1.11-3.26 folds in vitro. ABPS 1.00 x 10(3) mg.L-1 was shown to increase IL-2 production in Con A-stimulated aged mouse splenocytes from 6.7 +/- 1.0 u.ml-1 to 19.3 +/- 5.7 u.ml-1 in vitro. Sandwish-ELISA was used for the determination of TNF-alpha, TNF-beta and sIL-2R in cell suspension. The spectrophotometry with Griess reagent was used for the determination of NO in cell suspension. A method was developed for the determination of NOS activity in biological sample by HPLC. ABPS 50, 100 mg.kg-1 i.p. was found to markedly promote TNF-beta and NO release, but decrease sIL-2R production from Con A-stimulated aged rat splenocytes, the activity of NOS in those cells was increased. ABPS 100 mg.kg-1 i.p. elevated serum TNF-alpha and NO contents and the NOS activity induced by LPS 0.3 mg.kg-1 i.p. in aged rats. ABPS 50-800 mg.L-1 elevated TNF-alpha and NO production from PM phi and increased the NOS activity in PM phi in vitro, but showed no significant influence on TNF-alpha, NO release and on NOS activity induced by LPS 10 mg.L-1 for PM phi from aged rats. ABPS 100 mg.kg-1 i.p. elicited TNF-alpha, NO production and NOS activity for PM phi from aged rats, ABPS 100 mg.kg-1 i.p. showed a synergetic action with LPS 10 mg.L-1. When rats were treated with ABPS 50-800 mg.L-1 i.p., there was no significant difference on NO production on, and NOS activity in the cerebral cortex between those isolated from aged rats and those isolated from young rats. These results indicate that ABPS may prime and trigger M phi and has restorative effects on the deficiency of the immune system associated with aging in mice and rats.

[Inhibitory effect of matrine on lipopolysacchride-induced tumor necrosis factor and interleukin-6 production from rat Kupffer cells].

Abstract: The effect of matrine on the lipopolysacchride (LPS)-induced tumor necrosis factor and interleukin-6 production from rat Kupffer cell was investigated Results showed that matrine 125, 250 and 500 mgL-1 suppressed TNF and IL-6 production from Cal-primed Kupffer cells in the presence of lipopolysacchrides (LPS, 100 microgramsL-1) in a concentration-dependent manner Treatment with matrine 50 and 100 mgkg-1 before LPS injection(35 mgkg-1) markedly decreased mouse serum TNF and IL-6 The results suggest that matrine may have protective effect on LPS-induced liver injury

[Analysis of phenylethanoid glycosides of Herba cistanchis by RP-HPLC].

Abstract: The Chinese drug "Rou Cong-rong" (Herba Cistanchis) is one of the commonly used drugs in Chinese traditional medicine. It is used to reinforce the vital function of kidney, especially that of the sexual organs and induce laxation, for the treatment of impotence, premature ejaculation in men, infertility, morbid leukorrhea, profuse metrorrhagia in women, and chronic constipation in the aged. This paper deals with the qualitative and quantitative analysis of phenylethanoid glycosides of four species and one variety of Genus Cistanche and 23 lots of commercial crude drugs of Herba Cistanchis by RP-HPLC. The results were as follows: the chemical constituents of Cistanche deserticola Ma, C. salsa (C. A. Mey) G. Beck, C. salsa var. albiflora P. F. Tu et Z. C. Lou and C. tubulosa were similar while those of C. sinensis were different from the others; the contents of echinacoside and acteoside of C. salsa, which were 2.13% and 1.51%, were the highest of the genus Cistanche. An ODS column (Alltima C18, 5 microns, 250 x 4.6 mm) was employed. Linear gradient elution of acetonitrile--1.5% acetic acid was used as mobile phase, and concentration of acetontrile was from 8% to 20% (0-60 min) in the qualitative analysis, and from 11.5 to 20% (0-35 min) in the quantitative analysis. The flow rate was 1.2 ml.min-1. The detection wavelength was set at 335 nm.

Study on flavonoids in seeds of Hovenia dulcis

Abstract: Four flavanoids were isolated from the seed of Hovenia dulcis Thunb. On the basis of physicochemical properties and spectroscopic analysis, their structures were identified as dihydrokaempferol (I), quercetin (II), (+)-3,3',5',5,7-pentahydroflavanone (III) and (+)-dihydromyricetin (IV). Among them, III was a new compound; I and IV were first isolated from genus Hovenis.

[Protective action of corynoline, acetylcorynoline and protopine against experimental liver injury in mice].

Abstract: Oral administration of two doses of corynoline, acetylcorynoline or protopine at 50 and 100 mg·kg -1 in an interval of 8 to 24 h before ip injection of CCl 4, acetaminophen or thioacetamide significantly impeded the elevation of serum transaminase (SGPT) and liver damage in mice. The three compounds were found to inhibit CCl 4 induced microsomal lipid peroxidation and CCl 4 conversing to carbon monoxide in liver microsomes in vitro . Of these compounds, acetylcorynoline was shown to be more potent than corynoline and protopine. In addition, all the three compounds exhibited biphasic effects on the hepatic cytochrome P450, i.e. inhibition followed by induction, in mice.

Determination of sinomenine HCl in serum and urine by HPLC and its pharmacokinetics in normal volunteers

Abstract: A RP-HPLC method was developed to determine the concentrations of sinomenine HCl in serum and urine and its pharmacokinetics was studied in healthy volunteers. C18H37 column was eluted with the mobile phase of acetonitrile--0.01 mol.L-1 sodium phosphate monobasic--N, N, N', N'-tetramethylenediamine (46:54:0.22 v/v, pH 6.9) and the ultraviolet absorbance was monitored at 263 nm. Triazolan was used as internal standard. The calibration curves were linear in the range of 6-480 ng.ml-1 in serum and 0.06-3 micrograms.ml-1 in urine, with mean recoveries of 75.46% and 91.38% respectively. The lowest detectable limits were 4 ng.ml-1 in serum and 40 ng.ml-1 in urine and the RSD for the intra-day and inter-day were less than 5%. A single oral dose of 80 mg sinomenine HCl tablet was given to 8 healthy male volunteers. The concentrations of sinomenine HCl in serum and urine were determined. The serum concentration--time curve was found to fit a two-compartment open model with first order elimination. The pharmacokinetic parameters were: T1/2 alpha 0.791 +/- 0.491 h, T1/2 beta 9.397 +/- 2.425 h, Tmax 1.040 +/- 0.274 h, Cmax 246.604 +/- 71.165 ng.ml-1, AUC 2651.158 +/- 1039.050 ng.h.ml-1, CL 0.033 +/- 0.010 ng.ml-1.

[Study on the anti-apoptotic mechanism of ginsenoside Rg1 in cultured cortical neurons].

Abstract: Ginsenoside Rg1 is an active principle isolated from Panax ginseng CA Meyer. Primary neuronal culture was performed with different concentrations of Rg1. On the 14th day, the culture was changed to serum-free medium. On the 16th day, neurons were harvested and assayed under microscope and fluorescence microscope. The result showed that serum withdrawal from the medium induced apoptosis in primary cultured cortical neurons. Rg1 (1, 10 mumol.L-1) was shown to inhibit apoptosis and protect neurons against injury. Membrane fluidity was measured using fluorescence spectrophotometer in five groups of cultured cortical neurons: control (complete medium), apoptosis (serum-free medium), Rg1 0.1 mumol.L-1, Rg1 1 mumol.L-1 and Rg1 10 mumol.L-1. Neurons were isolated enzymatically and loaded with the fluorescent dye, DPH (1, 6-diphenyl-1,3,5-hexatriene). Membrane fluidity in control neurons (eta 1.2928 +/- 0.1426) was shown to be significantly higher than that in apoptosis cells (eta 2.9277 +/- 0.2004). The membrane fluidity of neurons treated with Rg1 (0.1, 1, 10 mumol.L-1) increased significantly (eta 2.9172 +/- 0.1604, 2.4731 +/- 0.2187, 1.6436 +/- 0.1483). These findings indicate a substantial alteration of membrane fluidity with neuronal apoptosis. Increment of membrane fluidity provides an aspect of elucidating the mechanism of Rg1's anti-apoptosis function.

Isolation and structure determination of xanthone glycosides of Anemarrhena asphodeloides

Abstract: Xilingzhimu, the rhizomes of Anemarrhena asphodeloides Bunge (Liliaceae), has been prescribed as antipyretic, anti-inflammatory, diuretic and hypoglycemic agents in Chinese traditional medicine. In this paper, two xanthone glycosides I and II, were isolated from Xilingzhimu by conventional method. The structures of I and II were identified on the basis of chemical reactions and UV, IR, 1HNMR, 13CNMR and DEPT. Compound I was identified as mangiferin and II is a new compound, named neomangiferin. Its structure is 7-O-beta-D-glucopyranosyl-mangiferin.

[A comparative study on effect of two bisbenzylisoquinolines, tetrandrine and berbamine, on reversal of multidrug resistance].

Abstract: A comparative study on the effect of two bisbenzylisoquinolines, tetrandrine (TTD) and berbamine (BBM), and verapamil (VRP) on reversing multidrug resistance was reported. TTD, BBM and VRP showed significant activity in reversing adriamycin (ADR) and vincristine (VCR) resistance in acquired resistant MCF-7/Adr and KBv200 cell lines, and the effect was shown to be dose-dependent. TTD, at the concentration of 10 mumol.L-1, completely reversed ADR resistance in MCF-7/adr cells. TTD, BBM and VRP increased intracellular ADR accumulation in MCF-7/adr cells. There is minor difference in structure between TTD and BBM. TTD showed greater activity than VRP in reversing MDR, while BBM showed similar activity to that of VRP. TTD also showed significant activity in vivo in reversing ADR resistance in MDR MCF-7/Adr solid tumor in nude mice.

[Studies on octanol-water partition coefficient and nasal drug absorption].

Abstract: In order to find out the quantitative relationship between physicochemical properties of drugs and their nasal absorption, diltiazem hydrochloride and paracetamol were selected as model drugs and their octanol water partition coefficient was determined In situ nasal recirculation method at different pH values was used to estimate the rate constant of nasal drug absorption in rats Results showed that quantitative relationship existed between partition coefficient and nasal absorption constant, with correlation coefficient being 0 9761( n =9) Besides methods of partition coefficient determination, the in situ nasal recirculation manipulation was also improved

Oleanolic acid saponins from the root bark of Aralia taibaiensis

Abstract: Five oleanolic acid saponins were isolated from the root bark of Aralia taibaiensis Z.Z. Wang et H.C. Zheng. By spectroscopic and chemical methods, they were identified as araloside A (1), 3-O-[alpha-L-arabinofuranosyl(1-->4)-6'-O-n-butyl-beta-D- glucuronopyranosyl]-oleanolic acid-28-O-beta-D-glucopyranoside (2), 3-O-[alpha-L-arabinofuranosyl(1-->4)-6'-O-ethyl-beta-D- glucuronopyra-nosyl]-oleanolic acid-28-O-beta-D-glucopyranoside (3), stipuleanoside R2(4) and 3-O-(beta-D-glucopyranosyl(1-->3) [alpha-L-arabinofuranosyl(1-->4)]-6'-O-ethyl-beta-D- glucuronopyranosyl)-oleanolic acid-28-O-beta-D-glucopyranoside (5). Saponin 1 and 4 were isolated from the title plant for the first time. 2, 3 and 5 are new compounds and named taibaienoside I, taibaienoside II and taibaienoside III, respectively.

Triterpene acids from the barks of Illicium difengpi

Abstract: Four compounds were isolated from the traditional Chinese medicine "Difengpi", barks of Illicium difengpi K.I.B. et K.I.M. They were identified as 3 beta-O-acetyl-mangiferolic acid (I), mangiferonic acid (II), mangiferolic acid (III) and butulinic acid (IV) by physico-chemical constants and spectral analyses (UV, IR, EIMS, 1HNMR, 13CNMR, NOEDE and 2D NMR). Compound I is a new compound. These triterpene acids (I-IV) were isolated from Illicium genus for the first time.

[Separation and determination of flavonols in the flowers of Carthamus tinctorius by RP-HPLC]

Abstract: Carthamus tinctorius L is a kind of traditional Chinese medicine used in the treatment of uterine congestion, cardio-vascular disease, thrombosis and so on Eight flavonoids have been isolated from its flowers A reversed phase HPLC method for the separation and determination of the three flavonols: rutin (I), quercetin(II) and kaempferol(III) in the flowers of Carthamus tinctorius L is described The column was 25 cm x 46 mm ID, packed with YWG-C18(10 microns) The mobile phase was a mixture of MeOH-H2O-H3PO4(485:515:025, pH 35) The flow rate was 10 mlmin-1 Daidzein was used as an internal standard UV detection was performed at 360 nm The relative standard deviation of the method was 11-26% The calibration curves showed good linearity over the range of 011-080 microgram, gamma = 09995-09998 and detection limits were 20-200 ng The recoveries were 978%-989% for the three flavonols The method is simple, fast, sensitive and accurate and has been applied to the analysis of Carthamus tinctorius L of different sources It can also be used for the quality control of safflower preparations for clinical uses

Studies on new cytotoxic annonaceous acetogenins from Uvaria grandiflora and absolute configurations

Abstract: Two new cytotoxic annonaceous acetogenins, named uvarigrin(1) and uvarigrandin A(3), were obtained from the roots of Uvaria grandiflora Roxb(Annonaceae). Based on X-ray analysis and Mosher's methodology, the overall absolute configuration of 1 was established as 15S, 17R, 18R, 21R, 22R, 36S. The absolute configuration of 3 was also resolved by Mosher's methodology. The relative configuration of the previously reported uvarigranin (2) was revised. Compound 1 showed cytotoxicity against HCT-8, Bel7402 and A2780 human tumor cell lines at ED50 levels of 0.15, 0.21 and 0.41 microgram.ml-1, respectively.

Synthesis and biological activity of tyrosine protein kinase inhibitors

Abstract: Four classes of 25 tyrosine protein kinase (TPK) inhibitors were designed and synthesized Compounds 1-10 were tested to inhibit TPK of HL-60 leukemia cell using 32P-ATP method, and some of them exhibit evident inhibitory activities Their structure-activity relationship is similar to that of TPK inhibitors reported in literatures Compounds 11-25 were tested to inhibit TPK of normal rat spleen cell using ELISA method and their SAR is different from that using 32P-ATP method

[Studies on the ganoderic acid, a new constituents from the fruiting body of Ganoderma lucidum (Fr.) Karst].

Abstract: Three compounds have been isolated from the dichloromethane soluble fraction of the fruiting body of Ganoderma lucidum (Fr.) Karst. On basis of spectral analyses (UV, IR, MS, 1HNMR, 13CNMR and 2D-NMR), they were identified as 3, 7-dioxo-lanosta-8, 24(E)-dien-26-oic acid (I), 7 beta-15 alpha-dihydroxy-3, 11, 23-trioxo-5 alpha-lanost-8-en-26-oic acid (II) and 3 beta, 7 beta, 15 alpha-trihydroxy-11, 23-dioxo-5 alpha-lanosta-8-en-26-oic acid (III). Compound I is a new compound named ganoderic acid DM.

Chemical investigation of genus Hedyotis. II. Isolation and identification of iridoids from Hedyotis chrysotricha

Abstract: Many species of genus Hedyotis (Rubiaceae) were used as folk medicine for treatment of cold, inflammation, cancer and etc in China The alcoholic extract of the whole plant of H chrysotricha showed good hepatoprotective effects From the alcoholic extract ten iridoids were isolated and their structures were elucidated as: asperuloside (1), scandoside methyl ester (2), asperulosidic acid (3), deacetyl asperulosidic acid (4), loganin (5), deacetyl asperuloside (6), acetyl scandoside methyl ester (7), 6 beta-hydroxy-genipin (8) and two new compounds named hedyoside (9) and 6'-acetylasperuloside (10), by means of chemical and spectral methods

Studies on the chemical constituents of Annona muricata

Abstract: Annonaceous acetogenin (or polyketide) is a kind of potential antineoplastic agents from Annonaceae plants. Two new acetogenins, Muricatalicin (I) and muricatalin (VI), a mesitoate of a new acetogenin, annonacin-B mesitoate (Vb), and three known acetogenins, annonacin (II), annonacin-A (III) and annonacin-10-one (IV) have been isolated from Annona muricata L. The structures and relative stereochemistry of I, VI and Vb were elucidated on the basis of spectral analysis and examination of their acetates and/or mesitoate.

Effect of age and ginsenoside Rg1 on nitric oxide content and nitric oxide synthase activity of cerebral cortex in rats

Abstract: Nitric oxide(NO) content and nitric oxide synthase(NOS) activity were measured in cerebral cortex isolated from Wistar rats of three age groups(young: 3 months; adult: 9 months; and old: 27 months). No significant differences in NO content and NOS activity between young and adult rats were found( P 0 05). The NO content and NOS activity in old rats were shown to be significantly higher than those of young and adult rats( P 0 01). When treated with Rg1(10, 20, 40 mg·kg -1 ), the NO content and NOS activity in old rats decreased. The inhibitory effect of Rg1 on NOS was found to be dose dependent in the range of 10～40 mg·kg -1 . The optimal reduction in NO content and NOS activity induced by Rg1 occurred at 40 mg·kg -1 for old rats( P 0.01). In view of the close relationship of NO content and NOS activity with aging, the inhibitory effect of Rg1 on NOS activity, as shown by our results, might provide an explanation for its antiaging function.

Isolation and identification of ecliptasaponin D from Eclipta alba (L.) Hassk

Abstract: A new triterpenoid glucoside ecliptasaponin D was isolated from Eclipta alba (L.) Hassk. Its structure was deduced as 3 beta, 16 beta-dihydroxy olean-12-ene-28-oic acid-3 beta-O-beta-D-glucopyranoside, based on spectral analysis and chemical evidences as well as results of hydrolysis.

A preliminary study on the identification of crude snake drugs by molecular genetic markers

Abstract: DNA was amplified from 11 samples of crude snake drugs by 2 random primers. "Wushaoshe" (Zaocys dhumnades) and its substitutes, Elaphe taeniurus, E. rufodorsata, E. carinata and Sinonatrix annularis, and "Jinqian Baihyashe" (Bungarus multicinctus) and its adulterants, Dinodon rufozonatum and Sinonatrix annularis, can be distinguished by electrophoresis pattern of the amplified products. The results showed that the molecular genetic marker technique can be used as a new method for the identification of crude snake drugs.

[Studies on the iridoid glucosides of the root of Lamiophlomis rotata (benth.) kudo, a medicinal plant in Xi zang (Tibet)].

Abstract: Lamiophlomis rotata (Labiatae) is a Chinese folk medicinal plant in Xi-zang (Tibet), which has effects of promoting blood circulation to remove blood stasis, subduing swelling and alleviating pain. Four iridoid glucosides were isolated from the root of the species. On the basis of IR, UV, NMR, MS spectral data and chemical methods, their structures were identified as: 8-O-acetylshanzhiside methyl ester(I), 6-O-acetylshanzhiside methyl ester(II), penstemoside(III) and 7, 8-dehydropenstemoside(IV). The last one is a new compound.

Studies on the triterpene sapogenins from Albizziae Cortex

Abstract: A new sapogenin named Julibrogenin A was isolated from the stem bark of Albizzia julibrissin Durazz ( Albizziae Cortex). Based on chemical and spectral studies, their structure has been identified as 21 O (2 hydroxymethyl 6 methyl 6 methoxyl 2,7 octadienoyl) acacic acid. In addition, machaerinic acid lactone, machaerinic acid methylester, acacigenin B and julibrotriterpenoidal lactone A were also isolated from this plant and characterised.

Determation of strychnine and brucine in Strychnos by HPLC

Abstract: This paper describes the determination of strychnine and brucine in the seeds, root, stem and leaves of Strychnos species by HPLC. The analytical column used was ZY110 YNG-C18. The mobile phase was KH2PO4(0.01 mol.L-1)--MeOH(73:27), pH2.5, regulated by 10% H3PO4. Flow rate was 1.0 ml.min-1. The detection wavelength was 264 nm. The linear ranges of strychmine and brucine were 0.18-7.26 micrograms and 0.11-4.32 micrograms, respectively. The recoveries of strychnine and brucine were 98.27% and 98.04%, respectively. The analytical results showed that the contents of strychnine and brucine in samples showed great difference between different species. The contents of strychnine in the seeds of Strychnos wallichiana and S. ignatii were 5.6% and 3.9%, respectively. These results show that the two Strychnos species may be developed as the resources of strychnine.

[Compared study on Fura-2/AM assay and MTT assay for screening multidrug resistant modulators].

Abstract: To explore the difference of screening results of reversing multidrug resistance (MDR) by modulators between Fura-2/AM assay and MTT assay, 25 compounds which have active structure were studied for MDR reversal activity with both methods. The fold of MDR reversal was shown to have remarkable relation with the amount of Fura-2 accumulation (Y = -3.66 + 17.5X, gamma = 0.86, P < 0.01). On the other hand, Fura-2/AM assay has several advantages as compared with MTT assay. Fura-2/AM assay needs shorter time (4 h) than MTT assay (96 h), and the MTT assay needs more steps than the Fura-2/AM assay. Furthermore, Fura-2/AM assay was more reliable than MTT assay for screening MDR modulators because MTT assay was dependent on the viable cells, while Fura-2/AM assay was dependent on the function of P-gp. The results suggest that Fura-2/AM assay may replace MTT assay in the screening of MDR modulators on a large scale.