Optimization of harvest and extraction factors by full factorial design for the improved yield of C-glucosyl xanthone mangiferin from Swertia chirata.

Swertia chirata Buch.-Ham. ex C.B. Clarke is an important medicinal plant used in various herbal formulations as it shows significant biological activities such as hepatoprotective, hypoglycemic, anti-inflammatory, antimalarial, antioxidant and anti-parkinson. C-glucosyl xanthone glycoside (mangiferin) is known as bio-marker compound of genus Swertia L. Development of efficient extraction methods of C-glucosyl xanthone mangiferin from Swertia chirata was attempted by optimizing the pre-harvest, post-harvest and extraction techniques by full factorial design. Firstly, a full factorial design was implemented to evaluate the single and interactive effects of pre-harvest (growth stage and plant part), post-harvest (drying condition and storage periods) followed by selection of best extraction technique such as heat reflux extraction (HRE), microwave assisted extraction (MAE) and ultrasound assistant extraction (UAE) at different solvent types on mangiferin yield. HPTLC and HPLC techniques were used for the determination of mangiferin content in extracts generated from different plant samples. In addition, anti-oxidant and anti-diabetic properties were determined by using DPPH assay and percentage inhibition of α­amylase enzyme. Substantial variation of mangiferin yield, ranged from 1.46 to 4.86% was observed, depending on the growth stage, plant part, drying condition, storage periods and extraction method. Results showed that drying of the leaves of Swertia chirata in the shade harvested at budding stage and stored for not more than 1 month was recommended for obtaining a higher mangiferin yield. Among different extraction techniques, MAE and UAE in 50% aqueous ethanol solvent were found to be efficient and cost-effective with better yield of mangiferin (4.82% and 4.86%, respectively) as compared to HRE (4.14%). Highest DPPH activity and percentage inhibition of α­amylase was observed in the aqueous ethanol extract of S. chirata leaves harvested at bud-stage of plant followed by flowering stage. The study shows that optimization of various factors by full factorial design was found to be an effective procedure to improve mangiferin yield from Swertia chirata and can be used for extraction of mangiferin.

Biotechnological interventions and genetic diversity assessment in Swertia sp.: a myriad source of valuable secondary metabolites.

The genus Swertia (Family: Gentianaceae) has cosmopolitan distribution which is present in almost all the continents except South America and Australia. Swertia genus has been renowned as one of the potent herbal drugs in the British, American, and Chinese Pharmacopeias as well as well-documented in the Indian traditional medicinal systems, viz. Ayurveda, Siddha, and Unani. Many species of this genus have therapeutic properties and have been used traditionally in the treatment of a number of health ailments viz. hepatitis, diabetes, inflammation, bacillary dysentery, cancer, malaria, fever etc. This genus is industrially important medicinal plant that has been used as a principal component in numerous marketed herbal/ polyherbal formulations. Medicinal usage of Swertia is endorsed to the miscellaneous compounds viz. xanthones, irridoids, seco-irridoids, and triterpenoids. A chain of systematic isolation of bio-active compounds and their diverse range of pharmacological effects during last 15-20 years proved this genus as industrially important plant. Due to the various practices of the Swertia species, annual demand is more than 100 tons per year for this important herb which is continuously increasing 10% annually. The market value rises 10% by the year as there is increased demand in national and international market resulted in adulteration of many Swertia spp. due to paucity of agricultural practices, exomorphological, phytochemical, and molecular characterization. Thus, efficient biotechnology methods are prerequisite for the mass production of authentic species, sustainable production of bio-active compounds and ex situ conservation. A chain of systematic biotechnological interventions in Swertia herb during last 20 years cover the assessment of genetic diversity, in vitro sustainable production of bio-active compounds and mass propagation of elite genotypes via direct and indirect organogenesis. This review attempts to present the comprehensive assessment on biotechnological process made in Swertia over the past few years. KEY POINTS: • Critical and updated assessment on biotechnological aspects of Swertia spp. • In vitro propagation and genetic diversity assessment in Swertia spp. • Biosynthesis and sustainable production of secondary metabolites in Swertia spp.

Validation and quantification of major biomarkers in 'Mahasudarshan Churna'- an ayurvedic polyherbal formulation through high-performance thin-layer chromatography.

BACKGROUND: Mahasudarshan Churna (MC) is a polyherbal Ayurvedic medicine that is employed in fever (especially chronic type), cold and malaria, improvement of digestion and appetite, removes toxins from the blood, boosts immunity and protects against common bacterial infections. METHODS: Validation and quantification of oleanolic acid (OA), ursolic acid (UA), mangiferin (M), gallic acid (GA), quercetin (Q) and curcumin (C) in commercial MC formulations by HPTLC method. Mobile phase, hexane: ethyl acetate: acetone (16.4: 3.6: 0.2, v/v) was used for the separation of OA and UA; ethyl acetate: glacial acetic acid: formic acid: water (20: 2.2: 2.2: 5.2 v/v) for the development of M; and toluene: ethyl acetate: formic acid (13.5: 9: 0.6 v/v) for the separation of GA, Q and C in crude sample extracts. Visualization and scanning were performed at λ = 530 nm for OA and UA, at λ = 254 nm for M and at λ = 366 nm for GA, Q and C. In addition, HPLC-PDA analysis was used to confirm the HPTLC results. RESULTS: Major bio-active compounds in MC formulations were oleanolic acid (1.54-1.78%), mangiferin (1.38-1.52%) and gallic acid (1.01-1.15%); followed by ursolic acid (0.79-0.98%), curcumin (0.45-0.67%) and quercetin (0.22-0.34%). CONCLUSION: Analysis of bio-active compounds in the present study was performed using HPTLC methods and later HPTLC results were compared with HPLC. These two methods give comparable results and there was no statistically significant difference between the mean values for all extracts. Present study concluded that this HPTLC technique is low cost, fast, precise, and accurate which can be employed for the quantification of xanthonoid (M), triterpenoids (OA, UA) and phenolics (GA, Q and C) in samples/formulations. Furthermore, present HPTLC method can be conveniently employed for routine quality control analysis of all the six marker compounds in marketed Ayurvedic/herbal formulations.

Anti-cancer activity of withaferin A in B-cell lymphoma.

Withaferin A (WA), a withanolide from the plant, Ashwagandha (Withania somnifera) used in Ayurvedic medicine, has been found to be valuable in the treatment of several medical ailments. WA has been found to have anticancer activity against various solid tumors, but its effects on hematological malignancies have not been studied in detail. WA strongly inhibited the survival of several human and murine B cell lymphoma cell lines. Additionally, in vivo studies with syngeneic-graft lymphoma cells suggest that WA inhibits the growth of tumor but does not affect other proliferative tissues. We demonstrate that WA inhibits the efficiency of NF-κB nuclear translocation in diffuse large B cell lymphomas and found that WA treatment resulted in a significant decrease in protein levels involved in B cell receptor signaling and cell cycle regulation. WA inhibited the activity of heat shock protein (Hsp) 90 as reflected by a sharp increase in Hsp70 expression levels. Hence, we propose that the anti-cancer effects of WA in lymphomas are likely due to its ability to inhibit Hsp90 function and subsequent reduction of critical kinases and cell cycle regulators that are clients of Hsp90.

Cytological evaluation of Apiaceae Lindl. from Western Himalayas.

The present paper deals with cytological studies on 31 populations covering 17 species belonging to 10 genera of Apiaceae from Western Himalayas. The chromosome numbers in the two species as Chaerophyllum capnoides (n = 11) and Heracleum brunonis (n = 11), along with additional cytotypes for Pimpinella acuminata (n = 9) and Sium latijugum (n = 12) have been reported for the first time on world-wide basis. The genus Pleurospermum, although cytologically worked out earlier from outside India, its species densiflorum (n = 11) makes first representation of the genus from India. Besides, the chromosome number in Chaerophyllum aromaticum (n = 11) have been worked out for the first time from India. The course of meiosis varies from normal to abnormal in different populations of Chaerophyllum villosum, Pimpinella achilleifolia and Sium latijugum while abnormal meiotic course has been observed in all the studied populations of Chaerophyllum acuminatum, C. aromaticum, C. capnoides, Pimpinella acuminata, P. diversifolia, Pleurospermum densiflorum and Vicatia coniifolia. Such taxa are marked with meiotic abnormalities in the form of cytomixis, chromatin stickiness, formation of laggards and bridges resulting into abnormal microsporogenesis. The occurrence of structural heterozygosity has been recorded in the Chaerophyllum acuminatum and C. aromaticum. The effect of these abnormalities is clearly seen on the pollen size and fertility.

Cytomorphological studies in some members of tribe Paniceae (Poaceae) from district Kangra of Himachal Pradesh (Western Himalayas).

The present paper deals with cytological studies on the population basis of 21 species belonging to 9 genera of tribe Paniceae of family Poaceae from cytologically unexplored area of Western Himalayas i.e. district Kangra of Himachal Pradesh for the assessment of genetic diversity of grass flora. On world-wide basis, the chromosome counts have been made for the first time for three species such as Brachiaria remota (n = 16), Digitaria granularis (n = 36) and Isachne albens (n = 5). Similarly, on India basis, altogether new records are made for two species such as Echinochloa cruspavonis (n = 27) and Paspalum distichum (2n = 50). A comparison of the different euploid cytotypes studied at present for Digitaria adscendens, D. setigera and Oplismenus compositus revealed significant variations in their morphology, depicting increase in some of the characters of polyploid cytotypes. The course of meiosis has been observed to be normal in all the studied populations with high pollen fertility except for two species such as Paspalum dilatatum and P. distichum marked with abnormal meiosis and reduced pollen fertility.

Cytological studies of Brassicaceae burn. (Cruciferae juss.) from Western Himalayas.

Cytological studies have been carried out on 12 species of Brassicaceae Burn. on population basis from different geographical areas of Kashmir and Himachal Pradesh in the Western Himalayas. Variable chromosome reports for Barbaraea intermedia (n = 16), Cardamine loxostemonoides (n = 8), Nasturtium officinale (n = 8), Sisymbrium orientale (n = 14) on world-wide basis have been added to the previous reports of these species. The chromosome numbers in seven species as Barbaraea intermedia (n = 8), B. vulgaris (n = 8), Capsella bursa-pastoris (n = 8), Descuriania sophia (n = 10), Rorippa islandica (n = 8), Sisymbrium strictum (n = 7) and Thlaspi alpestre (n = 7) have been worked out for the first time from India. The meiotic course in the populations of seven species such as Barbaraea intermedia, Capsella bursa-pastoris, Coronopus didymus, Descuriania sophia, Nasturtium officinale, Sisymbrium orientale and S. strictum varies from normal to abnormal while all the populations of two species Barbaraea vulgaris and Sisymbrium irio show abnormal meiotic course. Meiotic abnormalities are in the form of cytomixis, chromosomal stickiness, unoriented bivalents, inter-bivalent connections, formation of laggards and bridges, all resulting into abnormal microsporogenesis. Heterogenous sized fertile pollen grains and reduced reproductive potentialities have invariably been observed in all the meiotically abnormal populations. However, the meiotic course in all the populations of Cardamine loxostemonoides, Rorippa islandica and Thalspi alpestre is found to be normal with high pollen fertility.

Assessment of systemic interaction between Swertia chirata extract and its Bioactive constituents in rabbits.

The plant Swertia chirata (Gentianaceae) is known for its multifarious medicinal value in the Indian system of medicine (Ayurveda). Its methanol extracts having antidiabetic activity contains mangiferin, amarogentin, amaroswerin, sweroside and swertiamarin as active constituents. The pharmacokinetics of mangiferin and amarogentin have been carried out after intravenous administration of pure standards and extract from S. chirata (CT) in rabbits to assess systemic interaction. The remaining three components were also monitored in plasma for pharmacokinetic estimation based on the ratio analysis method. Mangiferin was characterized by a relative low clearance ( approximately 0.14 L/h/kg) and a lesser volume of distribution ( approximately 0.15 L/kg), while amarogentin exhibited a rapid clearance ( approximately 2.62 L/h/kg) and wide distribution ( approximately 1.08 L/kg) from the systemic circulation. No significant difference was observed in pharmacokinetic parameters of mangiferin and amarogentin either administered alone or as CT formulation in rabbits.

Therapeutic efficacy of undenatured type-II collagen (UC-II) in comparison to glucosamine and chondroitin in arthritic horses.

The present investigation evaluated arthritic pain in horses receiving daily placebo, undenatured type II collagen (UC-II) at 320, 480, or 640 mg (providing 80, 120, and 160 mg active UC-II, respectively), and glucosamine and chondroitin (5.4 and 1.8 g, respectively, bid for the first month, and thereafter once daily) for 150 days. Horses were evaluated for overall pain, pain upon limb manipulation, physical examination, and liver and kidney functions. Evaluation of overall pain was based upon a consistent observation of all subjects during a walk and a trot in the same pattern on the same surface. Pain upon limb manipulation was conducted after the walk and trot. It consisted of placing the affected joint in severe flexion for a period of 60 sec. The limb was then placed to the ground and the animal trotted off. The response to the flexion test was then noted with the first couple of strides the animal took. Flexion test was consistent with determining clinically the degree of osteoarthritis in a joint. Horses receiving placebo showed no change in arthritic condition, while those receiving 320 or 480 or 640 mg UC-II exhibited significant reduction in arthritic pain (P < 0.05). UC-II at 480 or 640 mg dose provided equal effects, and therefore, 480 mg dose was considered optimal. With this dose, reduction in overall pain was from 5.7 +/- 0.42 (100%) to 0.7 +/- 0.42 (12%); and in pain upon limb manipulation from 2.35 +/- 0.37 (100%) to 0.52 +/- 0.18 (22%). Although glucosamine and chondroitin treated group showed significant (P < 0.05) reduction in pain compared with pretreated values, the efficacy was less compared with that observed with UC-II. In fact, UC-II at 480 or 640 mg dose was found to be more effective than glucosamine and chondroitin in arthritic horses. Clinical condition (body weight, body temperature, respiration rate, and pulse rate), and liver (bilirubin, GGT, and ALP) and kidney (BUN and creatinine) functions remained unchanged, suggesting that these supplements were well tolerated.

Oxidative stress in cases of chronic fluoride intoxication.

This study was conducted to find out the level of oxidative stress and effect of supplementation of vitamin C, D and Calcium on levels of SOD, serum and urinary fluoride in children residing in endemic fluorosis area. For this the fluoride belt of Jaipur district was selected. The parameters selected were Super oxide dismutase, serum fluoride and urinary fluoride. The study was conducted on one hundred children, selected from four areas (25 from each area) consuming water containing 1.2, 2.4, 5.6 and 13.6 mg/l of fluoride. Drinking water fluoride, serum and urinary fluoride were measured by Ion selective electrode method. Serum SOD by Xanthine oxidase method using kit of Ransod (kit cat. No. SD125). The post treatment values showed a significant reduction in serum fluoride and SOD. Urinary fluoride levels increased significantly in post treatment stage. The results revealed a normal SOD levels in all groups but an increasing trend was observed with increasing fluoride concentration. Treatment with Calcium, Vitamin D and Vitamin C showed a significant reduction in serum fluoride and SOD and increase in urinary fluoride. A high positive correlation between pretreatment and post treatment group was observed in serum fluoride, SOD and urinary fluoride (P < 0.05). The study indicated an increasing oxidative stress in cases of fluorosis with increasing drinking water fluoride concentration. Treatment with Calcium, Vitamin D and Vitamin C resulted a significant reduction in serum fluoride and SOD and increase in urinary fluoride.

Simultaneous estimation of mangiferin and four secoiridoid glycosides in rat plasma using liquid chromatography tandem mass spectrometry and its application to pharmacokinetic study of herbal preparation.

Extracts from Swertia chirata (family Gentianaceae) have antidiabetics and antioxidant activity, largely attributed to the flavonoids and secoiridoids, which are a major class of functional components in methanolic extracts from aerial part of plants. In order to facilitate analysis of systemic exposure to S. chirata derived products in animals, we developed a liquid chromatography tandem mass spectrometry (LC-MS/MS) based method that is capable of routinely monitoring plasma levels of flavonoids and secoiridoids. An LC-MS/MS-based method has been developed for the simultaneous estimation of two bioactive markers, mangiferin and amarogentin along with three other components, amaroswerin, sweroside and swertiamarin in rat plasma. All the analytes including the internal standard (kutkoside) were chromatographed on RP-18 column (250 mm x 4 mm i.d., 5 microm.) coupled with guard column using acetonitrile: 0.5 mM ammonium acetate buffer, pH approximately 3.0 as mobile phase at a flow rate of 1 ml/min in gradient mode. The final flow to source was splitted in 1:1 ratio. The detection of the analytes was performed on API 4000 LC-MS/MS system in the multiple reaction-monitoring (MRM) mode. The quantitation for analytes other than the pure markers was based on relative concentration. The method was validated in terms of establishing linearity, specificity, sensitivity, recovery, accuracy and precision (Intra- and Inter-day), freeze-thaw stability, peltier stability, dry residue stability and long-term stability. The recoveries from spiked control samples were >90% for all analytes and internal standard except mangiferin where recovery was >60%. Intra- and inter-day accuracy and precision of the validated method were within the acceptable limits of <15% at low and <10% at other concentrations. The quantitation method was successfully applied to generate pharmacokinetic (PK) profile of markers as well as to detect other components in plasma after intravenous dose administration of herbal preparation in male Sprague-Dawley (SD) rats.

Therapeutic Efficacy and Safety of Undenatured Type II Collagen Singly or in Combination with Glucosamine and Chondroitin in Arthritic Dogs.

ABSTRACT This investigation was undertaken to evaluate the therapeutic efficacy and safety of glycosylated undenatured type II collagen (UC-II) alone or in combination with glucosamine HCl and chondroitin sulfate in arthritic dogs. Twenty dogs divided into four groups (n = 5) were daily treated orally for 120 days: group I, placebo; group II, 10 mg UC-II; group III, 2,000 mg glucosamine + 1,600 mg chondroitin; group IV, UC-II (10 mg) + glucosamine (2,000 mg) + chondroitin (1,600 mg), followed by a 30-day withdrawal period. On a monthly basis, dogs were examined for overall pain, pain upon limb manipulation, and exercise-associated lameness. Serum samples were analyzed for markers of liver function (ALT and bilirubin) and renal function (BUN and creatinine). Body weight was also measured at a monthly interval. Dogs in group I exhibited no change in arthritic conditions. Dogs receiving UC-II alone showed significant reductions in overall pain within 30 days (33%) and pain upon limb manipulation and exercise-associated lameness after 60 days (66% and 44%, respectively) of treatment. Maximum reductions in pain were noted after 120 days of treatment (overall pain reduction, 62%; pain reduction upon limb manipulation, 91%; and reduction in exercise-associated lameness, 78%). The overall activity of the dogs in the UC-II supplemented with glucosamine and chondroitin group (group IV) was significantly better than the glucosamine + chondroitin-supplemented group (group III). Glucosamine and chondroitin alleviated some pain, but in combination with UC-II (group IV) provided significant reductions in overall pain (57%), pain upon limb manipulation (53%), and exercise-associated lameness (53%). Following withdrawal of supplements, all dogs (groups II to IV) experienced a relapse of pain. None of the dogs in any groups showed any adverse effects or change in liver or kidney function markers or body weight. Data of this placebo-controlled study demonstrate that daily treatment of arthritic dogs with UC-II alone or in combination with glucosamine and chondroitin markedly alleviates arthritic-associated pain, and these supplements are well tolerated as no side effects were noted.

A sensitive and selective LC-MS-MS method for simultaneous determination of picroside-I and kutkoside (active principles of herbal preparation picroliv) using solid phase extraction in rabbit plasma: application to pharmacokinetic study.

A rapid, sensitive and selective LC-MS-MS method for the simultaneous quantitation of picroside-I and kutkoside (active constituents of herbal hepatoprotectant picroliv) was developed and validated in rabbit plasma. The analytes and internal standard (Amarogentin) were extracted using Oasis HLB solid phase extraction cartridges. Analysis was performed on Spheri RP-18 column (10 microm, 100 mm x 4.6 mm i.d.) coupled with guard column using acetonitrile:MilliQ water (50:50, %v/v) as mobile phase at a flow rate of 1 ml/min with a retention time of 1.39, 1.33 and 1.42 min for picroside-I, kutkoside and amarogentin, respectively. The quantitation was carried out using an API-4000 LC-MS-MS with negative electro spray ionization in multiple reaction monitoring (MRM) mode. The precursor to product ion transitions for picroside-I, kutkoside and amarogentin were m/z 491 > 147, 199; 511 > 167, 235; 585 > 227, respectively. The method was validated in terms of establishing linearity, specificity, sensitivity, recovery, accuracy and precision (within- and between-assay variation), freeze-thaw (f-t), auto injector and dry residue stability. Linearity in plasma was observed over a concentration range of 1.56-400 ng/ml with a limit of detection (LOD) of 0.5 ng/ml for both analytes. The recoveries from spiked control samples were > 60 and > 70% for picroside-I and kutkoside, respectively. Accuracy and precision of the validated method were within the acceptable limits of < 20% at low and < 15% at other concentrations. The analytes were stable after three freeze-thaw cycles and their dry residues were stable at -60 degrees C for 15 days. The method was successfully applied to determine concentrations of picroside-I and kutkoside post i.v. bolus administration of picroliv in rabbit.

Pattern profiling of the herbal preparation picroliv using liquid chromatography-tandem mass spectrometry.

At present, the construction of chromatographic fingerprints of complex herbal preparations in combination with mass spectrometry plays an important role in their development and standardization as potential therapeutic agents. Picroliv, an extract from roots and rhizomes of Picrorhiza kurroa, is a herbal hepatoprotective developed by CDRI. We report for the first time pattern profiling of various constituents of picroliv along with a precise and accurate method to estimate relative concentration of major components in the preparation by liquid chromatography-tandem mass spectrometry. In total, 27 components could be detected in multiple reaction monitoring (MRM) mode out of which fourteen could be quantified in terms of their relative concentration. Seven components were structurally correlated and confirmed based on the fragmentation pattern and information available in literature. The detection was carried out using MRM in negative ionization mode with analytes quantified from the summed total ion value of their most intense molecular ion transitions. The separation of various components was achieved using a gradient elution on RP-18 column with acetonitrile and Milli-Q water as mobile phase at a flow rate of 1.0 ml/min. The method was validated in terms of linearity, accuracy and precision (within- and between-assay variation) for 5 days. Linearity range was different for various components depending upon their sensitivity and abundance in the herbal preparation. Within- and between-assay accuracy (%bias) and precision (%R.S.D.) were within acceptable limits. The method was successfully applied to detect and determine relative concentrations of various components in two different batches of picroliv.

Activities of human recombination protein Rad51.

Homologous pairing and strand exchange, which are catalyzed by Escherichia coli RecA protein, are central to homologous recombination. Homologs of this protein are found in eukaryotes; however, little has been reported on the recombinase activities of the mammalian homologs, including the human protein, denoted HsRad51. For the studies described here, we purified HsRad51 form E. coli. Although the activities of HsRad51 and RecA were qualitatively similar in the presence of ATP, there were also striking differences. The stoichiometry of binding to DNA and the rate of renaturation of complementary strands were similar for the two proteins, but rates of ATP hydrolysis, homologous pairing, and subsequent strand exchange promoted by HsRad51 were less than 1/10 those of RecA. In addition, HsRad51 bound gamma-thio-ATP and formed stable presynaptic complexes that promoted renaturation as rapidly as RecA, but the recombinant human protein catalyzed neither strand exchange nor homologous pairing of a single strand with duplex DNA in the presence of the ATP analog. By contrast, RecA promoted both of the latter reactions in control experiments. These observations suggest that among RecA-like proteins, HsRad51 may be a variant in which homologous pairing and strand exchange are more closely linked to the hydrolysis of ATP.

Reversal of fluorosis in children.

Large populations consume fluoride-contaminated water, especially in developing countries. The toxic effects of fluorosis take three forms: clinical, skeletal and dental. Research thus far indicates that the manifestations of fluorosis are irreversible. However, it has been observed that the ingestion of calcium, vitamin C or vitamin D, individually, is effective in protection from fluoride toxicity to a certain extent. Therefore, a double blind control trial was conducted to examine the effect of a combination of calcium, vitamin D3 and ascorbic acid supplementation in fluorosis-affected children. In the present study, 25 children were selected from an area consuming water containing 4.5 p.p.m. of fluoride, All the children were in the age group 6-12 years and weighed 18-30 kg. They were graded for clinical, radiological and dental fluorosis and relevant biochemical parameters. Grade I skeletal fluorosis and all grades of the manifestation of dental and clinical fluorosis were observed. The children were given ascorbic acid, calcium and vitamin D3 well below the toxic dosages in a double blind manner using lactose as a placebo. Follow up revealed a significant improvement in dental, clinical and skeletal fluorosis and relevant biochemical parameters in these children. Thus, the study indicated that fluorosis can be reversed, at least in children, by a therapeutic regimen that is fairly cheap, simple and easily available and without any side effects.

Use of a microsome-mediated test system to assess efficacy and mechanisms of cancer chemopreventive agents.

There is a growing need for short-term assays which can assess the mechanisms and efficacy of cancer chemopreventive agents. In the present study we have employed a microsome-mediated test system concomitantly with DNA adduct detection to assess the efficacy of five chemopreventive agents, N-acetylcysteine, butylated hydroxytoluene (BHT), curcumin, oltipraz, and ellagic acid. 32P-Postlabeling analysis of DNA incubated with benzo[a]pyrene (BP) in the presence of Aroclor 1254-induced microsomes produced two major adducts: one derived from the interaction of benzo[a]pyrene-7,8-diol-9,10-epoxide (BPDE) with deoxyguanosine (dG) and the other from further activation of 9-OH-BP (309 and 34 adducts/10(7) nucleotides, respectively). With the exception of N-acetylcysteine, all test agents significantly altered BP-DNA adduct levels: Intervention with ellagic acid and oltipraz substantially (64-94%) inhibited both BPDE-dG and 9-OH-BP adducts, while intervention with curcumin and BHT inhibited the BPDE-dG adduct (57% and 38%, respectively) and enhanced the 9-OH-BP adduct (230% and 650%, respectively). Furthermore, ellagic acid was the only test agent observed to inhibit the anti BPDE-dG adduct in the absence of microsomal enzymes, which is consistent with the known conjugation of ellagic acid with BPDE. These results suggest that oltipraz may be acting as an inhibitor of P4501A1, the isozyme involved in activation of BP to BPDE, or by conjugation of the electrophilic species by a metabolite of oltipraz. A plausible mechanism for inhibition of the BPDE-dG adduct and enhancement of the 9-OH-BP adduct by curcumin and BHT includes inhibition of epoxide hydrolase. Our results also indicate that N-acetylcysteine does not act as an electrophilic trapping agent of BP metabolites but may exert its protective effect in vivo by various other means, including modulation of detoxification enzymes and altering DNA repair processes. These data suggest that this cell-free system in conjunction with the sensitive 32P-postlabeling DNA adduct analysis may prove a viable test system for assessing the mechanisms and efficacy of chemopreventive agents.

Effect of dietary methionine and inorganic sulfate with and without calcium supplementation, on urinary calcium excretion of guinea pigs (Cavia porcellus).

Supplementation of sodium sulfate and DL-methionine along with the standard diet to guinea pigs nearly doubled the urinary calcium in 6 weeks. This was probably due to decreased tubular reabsorption of calcium which was complexed with sulfate in the tubular lumen. A mild calcium load didn't further enhance calcium excretion in sodium sulfate supplemented group, but did so in methionine supplemented group. It may be due to methionine which might have increased the intestinal absorption of calcium. Both of these compounds increased citric acid excretion and decreased magnesium excretion.

Effect of dietary salt (NaCl) supplementation on urinary profile of guinea pigs (Cavia porcellus).

Sodium chloride supplementation (120 mg/kg of body weight/day) for 12 days increased the urinary excretion of calcium from 91.6 +/- 9.0 to 159.4 +/- 16.0 mumol/day and of sulphate from 266.8 +/- 24.5 to 1176.9 +/- 87.2 mumol/day in guinea pigs. The stone risk due to increased urinary calcium excretion could possibly be counterbalanced by increasing urinary sulphate excretion. High salt intake, thus, could not increase the risk of stone formation.