Real-Time Volumetric Phase Monitoring: Advancing Chemical Analysis by Countercurrent Separation.

Countercurrent separation (CCS) utilizes the differential partitioning behavior of analytes between two immiscible liquid phases. We introduce the first platform ("CherryOne") capable of real-time monitoring, metering, and control of the dynamic liquid-liquid CCS process. Automated phase monitoring and volumetrics are made possible with an array of sensors, including the new permittivity-based phase metering apparatus (PMA). Volumetric data for each liquid phase are converted into a dynamic real-time display of stationary phase retention (Sf) and eluent partition coefficients (K), which represent critical parameters of CCS reproducibility. When coupled with the elution-extrusion operational mode (EECCC), automated Sf and K determination empowers untargeted and targeted applications ranging from metabolomic analysis to preparative purifications.

Essential parameters for structural analysis and dereplication by (1)H NMR spectroscopy.

The present study demonstrates the importance of adequate precision when reporting the δ and J parameters of frequency domain (1)H NMR (HNMR) data. Using a variety of structural classes (terpenoids, phenolics, alkaloids) from different taxa (plants, cyanobacteria), this study develops rationales that explain the importance of enhanced precision in NMR spectroscopic analysis and rationalizes the need for reporting Δδ and ΔJ values at the 0.1-1 ppb and 10 mHz level, respectively. Spectral simulations paired with iteration are shown to be essential tools for complete spectral interpretation, adequate precision, and unambiguous HNMR-driven dereplication and metabolomic analysis. The broader applicability of the recommendation relates to the physicochemical properties of hydrogen ((1)H) and its ubiquity in organic molecules, making HNMR spectra an integral component of structure elucidation and verification. Regardless of origin or molecular weight, the HNMR spectrum of a compound can be very complex and encode a wealth of structural information that is often obscured by limited spectral dispersion and the occurrence of higher order effects. This altogether limits spectral interpretation, confines decoding of the underlying spin parameters, and explains the major challenge associated with the translation of HNMR spectra into tabulated information. On the other hand, the reproducibility of the spectral data set of any (new) chemical entity is essential for its structure elucidation and subsequent dereplication. Handling and documenting HNMR data with adequate precision is critical for establishing unequivocal links between chemical structure, analytical data, metabolomes, and biological activity. Using the full potential of HNMR spectra will facilitate the general reproducibility for future studies of bioactive chemicals, especially of compounds obtained from the diversity of terrestrial and marine organisms.

Screening natural products for inhibitors of quinone reductase-2 using ultrafiltration LC-MS.

Inhibitors of quinone reductase-2 (NQO2; QR-2) can have antimalarial activity and antitumor activities or can function as chemoprevention agents by preventing the metabolic activation of toxic quinones such as menadione. To expedite the search for new natural product inhibitors of QR-2, we developed a screening assay based on ultrafiltration liquid chromatography-mass spectrometry that is compatible with complex samples such as bacterial or botanical extracts. Human QR-2 was prepared recombinantly, and the known QR-2 inhibitor, resveratrol, was used as a positive control and as a competitive ligand to eliminate false positives. Ultrafiltration LC-MS screening of extracts of marine sediment bacteria resulted in the discovery of tetrangulol methyl ether as an inhibitor of QR-2. When applied to the screening of hop extracts from the botanical, Humulus lupulus L., xanthohumol and xanthohumol D were identified as ligands of QR-2. Inhibition of QR-2 by these ligands was confirmed using a functional enzyme assay. Furthermore, binding of xanthohumol and xanthohumol D to the active site of QR-2 was confirmed using X-ray crystallography. Ultrafiltration LC-MS was shown to be a useful assay for the discovery of inhibitors of QR-2 in complex matrixes such as extracts of bacteria and botanicals.

Dynamic residual complexity of natural products by qHNMR: solution stability of desmethylxanthohumol.

The use of chromatographic assays to assess the residual complexity of materials that are purified from natural sources by chromatographic means is, in a sense, a case of the fox watching the henhouse. Beside their static residual complexity, which is intrinsic to their metabolic origin, biologically active natural materials can also be involved in chemical reactions that lead to dynamic residual complexity. The present study examines the dynamics of the hop prenylphenol, desmethylxanthohumol (DMX), by means of quantitative (1)H-NMR (qHNMR) in a setting that mimics IN VITRO and physiological conditions. The experiments provide a comprehensive, time-resolved, and mechanistic picture of the spontaneous isomerization of DMX into congeneric flavanones, including their (1)H/(2)D isotopomers. Formation of the potent phytoestrogen, 8-prenylnaringenin (8PN), suggests that measurable estrogenic activity even of high-purity DMX is an artifact. Together with previously established qHNMR assays including purity activity relationships (PARs), dynamic qHNMR assays complement important steps of the post-isolation evaluation of natural products. Thus, qHNMR allows assessment of several unexpected effects that potentially break the assumed linkage between a single chemical entity (SCE) and biological endpoints.

Purity-activity relationships of natural products: the case of anti-TB active ursolic acid.

The present study explores the variability of biological responses from the perspective of sample purity and introduces the concept of purity-activity relationships (PARs) in natural product research. The abundant plant triterpene ursolic acid (1) was selected as an exemplary natural product due to the overwhelming number yet inconsistent nature of its approximate 120 reported biological activities, which include anti-TB potential. Nine different samples of ursolic acid with purity certifications were obtained, and their purity was independently assessed by means of quantitative 1H NMR (qHNMR). Biological evaluation consisted of determining MICs against two strains of virulent Mycobacterium tuberculosis and IC50 values in Vero cells. Ab initio structure elucidation provided unequivocal structural confirmation and included an extensive 1H NMR spin system analysis, determination of nearly all J couplings and the complete NOE pattern, and led to the revision of earlier reports. As a net result, a sigmoid PAR profile of 1 was obtained, demonstrating the inverse correlation of purity and anti-TB bioactivity. The results imply that synergistic effects of 1 and its varying impurities are the likely cause of previously reported antimycobacterial potential. Generating PARs is a powerful extension of the routinely performed quantitative correlation of structure and activity ([Q]SAR). Advanced by the use of primary analytical methods such as qHNMR, PARs enable the elucidation of cases like 1 when increasing purity voids biological activity. This underlines the potential of PARs as a tool in drug discovery and synergy research and accentuates the need to routinely combine biological testing with purity assessment.

In vivo estrogenic comparisons of Trifolium pratense (red clover) Humulus lupulus (hops), and the pure compounds isoxanthohumol and 8-prenylnaringenin.

UNLABELLED: The lack of a safe and reliable alternative to hormone therapy (HT) for treating menopausal symptoms underscores the need for alternative therapies. OBJECTIVE: The purpose of this study was to assess the in vivo estrogenic effects of the botanical dietary supplements Trifolium pratense (red clover) and Humulus lupulus (hops), and two compounds obtained from H. lupulus, isoxanthohumol and 8-prenylnaringenin (8-PN) using the ovariectomized uterotrophic adult rat model. A H. lupulus extract and a 30% isoflavone extract of T. pratense were tested at three escalating doses as was one dose of isoxanthohumol for 21d. 8-Prenylnaringenin, the major estrogen in H. lupulus, was also tested at three relevant escalating doses. In order to determine the in vivo metabolism of 8-PN, the major phases I and II metabolites were also identified. The primary outcome measure, uterus weight gain, indicated that H. lupulus and T. pratense did not have an estrogenic effect on the uterus, and none of the secondary outcome measures were positive. In contrast, there was a clear dose response when 8-PN was evaluated where the middle and high doses of 8-PN were active. 8-Prenylnaringenin in rat plasma, liver, and mammary gland was measured and the major phases I and II 8-PN metabolites were detected. Our findings suggest that while both the H. lupulus and T. pratense extracts do not have an effect on the rat uterus, 8-PN at equivalent doses to those previously used in humans did have an effect, and may therefore have a deleterious effect in women.

Binding of the hop (Humulus lupulus L.) chalcone xanthohumol to cytosolic proteins in Caco-2 intestinal epithelial cells.

Used in the brewing of beer, hops (Humulus lupulus L.) contain the prenylated chalcone xanthohumol, which is under investigation as a cancer chemoprevention agent and as a precursor for the estrogenic flavanones isoxanthohumol and 8-prenylnaringenin. The uptake, transport and accumulation of xanthohumol were studied using the human intestinal epithelial cell line Caco-2 to help understand the poor bioavailability of this chalcone. Studies were carried out using Caco-2 cell monolayers 18-21 days after seeding. The apparent K(m) and V(max) values of xanthohumol accumulation in Caco-2 cells were determined, and the protein binding of xanthohumol in sub-cellular fractions of Caco-2 cells was investigated. Approximately 70% of xanthohumol added to the apical side of Caco-2 cells accumulated inside the cells, while 93% of the intracellular xanthohumol was localized in the cytosol. Xanthohumol accumulation was temperature dependent and saturable with an apparent K(m )value of 26.5 +/- 4.66 muM and an apparent V(max) of 0.215 +/- 0.018 nmol/mg protein/min. Facilitated transport was not responsible for the uptake of xanthohumol, instead, accumulation inside the Caco-2 cells was apparently the result of specific binding to cytosolic proteins. These data suggest that specific binding of xanthohumol to cytosolic proteins in intestinal epithelial cells contributes to the poor oral bioavailability observed previously in vivo.

In vitro studies of intestinal permeability and hepatic and intestinal metabolism of 8-prenylnaringenin, a potent phytoestrogen from hops (Humulus lupulus L.).

PURPOSE: The absorption potential and metabolism of 8-prenylnaringenin (8-PN) from hops (Humulus lupulus L.) were investigated. 8-PN is a potent estrogen with the potential to be used for the relief of menopausal symptoms in women. METHODS: Monolayers of the human intestinal epithelial cancer cell line Caco-2 and human hepatocytes were incubated with 8-PN to model its intestinal absorption and hepatic metabolism, respectively. RESULTS: The apparent permeability coefficients for 8-PN in the apical-to-basolateral and basolateral-to-apical directions of a Caco-2 monolayer were 5.2 +/- 0.7 x 10(-5) and 4.9 +/- 0.5 x 10(-5) cm/s, respectively, indicating good intestinal absorption via passive diffusion. Both glucuronide and sulfate conjugates of 8-PN were detected in the Caco-2 cell incubations. The 4'-O-glucuronide was the predominant Caco-2 cell metabolite, followed by 7-O-sulfate and 4'-O-sulfate. Both phase I and phase II metabolites of 8-PN were formed by human hepatocytes. The 7-O-glucuronide was the most abundant hepatocyte metabolite, and no sulfate conjugates were detected. Incubations with various cDNA-expressed UDP-glucuronosyltransferases indicated that the isozymes UGT1A1, UGT1A6, UGT1A8, and UGT1A9 were responsible for glucuronidation of 8-PN. CONCLUSIONS: Although orally administered 8-PN should be readily absorbed from the intestine, its bioavailability should be reduced significantly by intestinal and hepatic metabolism.

Identification of human hepatic cytochrome P450 enzymes involved in the metabolism of 8-prenylnaringenin and isoxanthohumol from hops (Humulus lupulus L.).

The female flowers of hops (Humulus lupulus L.) are used in the brewing of beer and are under investigation for use in dietary supplements for the management of menopausal symptoms in women. Hop extracts contain the weakly estrogenic compound isoxanthohumol (IX), proestrogenic xanthohumol, and the potent estrogen 8-prenylnaringenin (8PN). Because IX can be metabolized in the human liver to form 8PN, the specific cytochrome P450 (P450) enzymes responsible for this O-demethylation reaction were identified. In addition, the enzymes that convert IX and 8PN to their most abundant metabolites were identified because these metabolic pathways might also affect the estrogenicity of hop preparations. Specifically, the P450 enzymes that catalyze the oxidation of the prenyl side chains of IX and 8PN into trans- or cis-alcohols were investigated. Human liver microsomes and monoclonal antibodies that inhibit specific P450 enzymes were used in combination with liquid chromatography/mass spectrometry to identify the enzymes responsible for these transformations. CYP2C19 was found to catalyze the formation of both cis- and trans-alcohols of the prenyl side chain of 8PN with K(m) values of 14.8 +/- 3.2 and 16.6 +/- 4.6 microM, respectively. CYP2C8 converted 8PN regioselectively to the trans-alcohol of the prenyl group with a K(m) of 3.7 +/- 0.9 microM. Finally, CYP1A2 was found to catalyze the O-demethylation of IX to generate 8PN, with a K(m) value of 17.8 +/- 3.7 microM. These results suggest that the estrogenicity of hop constituents in vivo will depend in part on metabolic conversion that may show individual variation.

In vitro susceptibility of Helicobacter pylori to botanical extracts used traditionally for the treatment of gastrointestinal disorders.

The gram-negative bacterium Helicobacter pylori (HP), identified in 1982, is now recognized as the primary etiological factor associated with the development of gastritis and peptic ulcer disease. In addition, HP infections are also associated with chronic gastritis, gastric carcinoma and primary gastric B-cell lymphoma. For centuries, herbals have been used in traditional medicine to treat a wide range of ailments, including gastrointestinal (GI) disorders such as dyspepsia, gastritis and peptic ulcer disease (PUD). However, the mechanism of action by which these botanicals exert their therapeutic effects has not been completely elucidated. As part of an ongoing screening program, the study assessed the in vitro susceptibility of 15 HP strains to botanical extracts, which have a history of traditional use in the treatment of GI disorders. Methanol extracts of Myristica fragrans (seed) had a MIC of 12.5 microg/mL; Zingiber officinale (ginger rhizome/root) and Rosmarinus officinalis (rosemary leaf) had an MIC of 25 microg/mL. Methanol extracts of botanicals with a MIC of 50 microg/mL included Achillea millefolium, Foeniculum vulgare (seed), Passiflora incarnata (herb), Origanum majorana (herb) and a (1:1) combination of Curcuma longa (root) and ginger rhizome. Botanical extracts with a MIC of 100 microg/mL included Carum carvi (seed), Elettaria cardamomum (seed), Gentiana lutea (roots), Juniper communis (berry), Lavandula angustifolia (flowers), Melissa officinalis (leaves), Mentha piperita (leaves) and Pimpinella anisum (seed). Methanol extracts of Matricaria recutita (flowers) and Ginkgo biloba (leaves) had a MIC > 100 microg/mL.

Comparison of the in vitro estrogenic activities of compounds from hops (Humulus lupulus) and red clover (Trifolium pratense).

Because the prevailing form of hormone replacement therapy is associated with the development of cancer in breast and endometrial tissues, alternatives are needed for the management of menopausal symptoms. Formulations of Trifolium pratense L. (red clover) are being used to alleviate menopause-associated hot flashes but have shown mixed results in clinical trials. The strobiles of Humulus lupulusL. (hops) have been reported to contain the prenylflavanone, 8-prenylnaringenin (8-PN), as the most estrogenic constituent, and this was confirmed using an estrogen receptor ligand screening assay utilizing ultrafiltration mass spectrometry. Extracts of hops and red clover and their individual constituents including 8-PN, 6-prenylnaringenin (6-PN), isoxanthohumol (IX), and xanthohumol (XN) from hops and daidzein, formononetin, biochanin A, and genistein from red clover were compared using a variety of in vitro estrogenic assays. The IC50 values for the estrogen receptor alpha and beta binding assays were 15 and 27 microg/mL, respectively, for hops and 18.0 and 2.0 microg/mL, respectively, for the red clover extract. Both of the extracts, genistein, and 8-PN activated the estrogen response element (ERE) in Ishikawa cells while the extracts, biochanin A, genistein, and 8-PN, significantly induced ERE-luciferase expression in MCF-7 cells. Hop and red clover extracts as well as 8-PN up-regulated progesterone receptor (PR) mRNA in the Ishikawa cell line. In the MCF-7 cell line, PR mRNA was significantly up-regulated by the extracts, biochanin A, genistein, 8-PN, and IX. The two extracts had EC50 values of 1.1 and 1.9 microg/mL, respectively, in the alkaline phosphatase induction assay. On the basis of these data, hops and red clover could be attractive for the development as herbal dietary supplements to alleviate menopause-associated symptoms.

Xanthohumol isolated from Humulus lupulus Inhibits menadione-induced DNA damage through induction of quinone reductase.

The female parts of hops (Humulus lupulus L.) show estrogenic effects as well as cancer chemopreventive potential. We analyzed the chemopreventive mechanism of hops by studying its antioxidative activities and its effect on the detoxification of a potentially toxic quinone (menadione). The detoxification enzyme quinone reductase [(NAD(P)H:quinone oxidoreductase, QR] protects against quinone-induced toxicity and has been used as a marker in cancer chemoprevention studies. Although the hop extract was only a weak quencher of free radicals formed from 1,1-diphenyl-2-picrylhydrazyl, it demonstrated strong QR induction in Hepa 1c1c7 cells. In addition, compounds isolated from hops including xanthohumol (XH) and 8-prenylnaringenin were tested for QR induction. Among these, XH was the most effective at inducing QR with a concentration required to double the specific activity of QR (CD value) of 1.7 +/- 0.7 microM. In addition, pretreatment of Hepa1c1c7 cells with XH significantly inhibited menadione-induced DNA single-strand breaks. The QR inhibitor dicumarol reversed the protective effect of XH against menadione-induced DNA damage. Because the expression of QR and other detoxifying enzymes is known to be upregulated by binding of the transcription factor Nrf2 to the antioxidant response element (ARE), the reporter activity mediated by ARE in HepG2-ARE-C8 cells was investigated after incubation with XH for 24 h. Under these conditions, XH increased ARE reporter activity in a dose-dependent manner. One mechanism by which XH might induce QR could be through interaction with Keap1, which sequesters Nrf2 in the cytoplasm, so that it cannot activate the ARE. Using LC-MS-MS, we demonstrated that XH alkylates human Keap1 protein, most likely on a subset of the 27 cysteines of Keap1. This suggests that XH induces QR by covalently modifying the Keap1 protein. Therefore, XH and hops dietary supplements might function as chemopreventive agents, through induction of detoxification enzymes such as QR.

Metabolism of xanthohumol and isoxanthohumol, prenylated flavonoids from hops (Humulus lupulus L.), by human liver microsomes.

The female flowers of hops (Humulus lupulus L.) used to flavor beer contain the prenylated flavonoids xanthohumol (XN) and isoxanthohumol (IX). IX is moderately estrogenic in vitro and XN has pharmacological properties that might make it useful as a cancer chemopreventive agent. The metabolism of these dietary flavonoids was investigated in vitro using human liver microsomes. Hydroxylation of a prenyl methyl group was the primary route of oxidative metabolism forming either cis or trans hydroxylated metabolites of IX but only the trans isomer of XN. The double bond on the prenyl group of both compounds formed an epoxide which was opened by an intramolecular reaction with the neighboring hydroxyl group. The potent phytoestrogen 8-prenylnaringenin (8-PN) was detected as a demethylation product of IX. However, the analogous demethylation reaction was not observed for XN. Since XN can be converted to IX through acid-catalyzed cyclization in the stomach, XN might contribute to the in vivo levels of estrogenic 8-PN following consumption of hops extracts.

Estrogens and congeners from spent hops (Humulus lupulus).

Estrogenicity-directed fractionation of a methanol extract of the strobiles of Humulus lupulus that had been extracted previously with supercritical CO(2), known as "spent hops", led to the isolation and identification of 22 compounds including 12 prenylated chalcones (1-8, 10-13), five prenylflavanones (14-17), 4-hydroxybenzaldehyde (18), sitosterol-3-O-beta-glucopyranoside (19), humulinone (20), and cohumulinone (21). In addition, the prenylated chalcone xanthohumol C (9a) was obtained as a 6:1 mixture along with its 1' ',2' '-dihydro derivative (9b). Three new chalcones (4, 11, 12) and four previously unreported constituents of hops (5, 6, 9b, 13) are reported. The structures of the new compounds were determined through a combination of spectrometric techniques including 1D and 2D NMR, HRESIMS, and ESIMS-MS. Full 1H NMR spin system analyses were performed to characterize the higher-order glucopyranosyl, prenyl, and chalcone B-ring spectra of the isolates. The principle estrogen 8-prenylnaringenin (15) from hops is an artifact formed along with its positional isomer 6-prenylnaringenin (16) through the spontaneous isomerization of the pro-estrogenic chalcone DMX (7).

Metabolism of 8-prenylnaringenin, a potent phytoestrogen from hops (Humulus lupulus), by human liver microsomes.

The female flowers of hops are used throughout the world as a flavoring agent for beer. Recently, there has been increasing interest in the potential estrogenic properties of hop extracts. Among the possible estrogenic compounds in hops, 8-prenylnaringenin is perhaps most significant due to its high in vitro potency exceeding that of other known phytoestrogens. Since data regarding the pharmacokinetic properties of this compound are lacking, we investigated the in vitro metabolism of 8-prenylnaringenin by human liver microsomes. A total of 12 metabolites were identified, and biotransformation occurred on the prenyl group and the flavanone skeleton. The major site of oxidation was on the terminal methyl groups, and of the two possible isomers, the transisomer was more abundant. The double bond on the prenyl group was also oxidized to an epoxide that was opened by intramolecular reaction with the neighboring hydroxyl group. On the flavanone skeleton, the major site of oxidation was at 3'position on the B ring. Other metabolites included oxidation at carbon-3 as well as desaturation of the C ring to produce 8-prenylapigenin. An unusual hydroxy quinone product formed by ipso hydroxylation of the B ring of 8-prenylnaringenin was also detected. This product was probably an intermediate for the B ring cleavage product, 8-prenylchromone.

Antimicrobial constituents from goldenseal (the Rhizomes of Hydrastis canadensis) against selected oral pathogens.

Two new C-methyl flavonoids, 6,8-di- C-methylluteolin 7-methyl ether (1) and 6- C-methylluteolin 7-methyl ether (2), were isolated from a commercially available sample of the roots of Hydrastis canadensis, along with seven known compounds, berberine (3), beta-hydrastine (4), canadine (5), canadaline (6), isocorypalmine (7), canadinic acid (8), and beta-sitosterol 3- O-beta- D-glucoside (9). The structures of the new compounds 1 and 2 were elucidated on the basis of their spectral data including 1D and 2D NMR techniques. Of these isolates, berberine (3) and, to a lesser extent, 1 and 2, showed antimicrobial activity when evaluated against the oral pathogens Streptococcus mutans and Fusobacterium nucleatum. Berberine (3) exhibited an additive antimicrobial effect when tested against S. mutans in combination with 1.

In vitro susceptibility of Helicobacter pylori to isoquinoline alkaloids from Sanguinaria canadensis and Hydrastis canadensis.

Methanol extracts of the rhizomes of Sanguinaria canadensis, and the roots and rhizomes of Hydrastis canadensis, two plants used traditionally for the treatment of gastrointestinal ailments, were screened for in vitro antibacterial activity against 15 strains of Helicobacter pylori. The rhizome extracts, as well as a methanol extract of S. canadensis suspension-cell cultures inhibited the growth of H. pylori in vitro, with a MIC50 range of 12.5-50.0 microg/ml. Three isoquinoline alkaloids were identified in the active fraction. Sanguinarine and chelerythrine, two benzophenanthridine alkaloids, inhibited the growth of the bacterium, with an MIC50 of 50.0 and 100.0 microg/ml, respectively. Protopine, a protopine alkaloid, also inhibited the growth of the bacterium, with a MIC50 of 100 microg/ml. The crude methanol extract of H. canadensis rhizomes was very active, with an MIC50 of 12.5 microg/ml. Two isoquinoline alkaloids, berberine and beta-hydrastine, were identified as the active constituents, and having an MIC50 of 12.5 and 100.0 microg/ml, respectively.

Black cohosh: an alternative therapy for menopause?

Due to the long-term health risks now associated with hormone replacement therapy, many menopausal women are actively seeking alternative treatments. One such alternative is black cohosh (Actaea racemosa, syn. Cimicifuga racemosa), which has been used in the United States for the treatment of gynecologic complaints for more than 100 years. Review of the published clinical data suggests that black cohosh may be useful for the treatment of menopausal symptoms, such as hot flashes, profuse sweating, insomnia, and anxiety. Results from the most recently published trial, however, indicate that black cohosh is not effective for the treatment of menopausal symptoms in breast cancer survivors being treated with tamoxifen. Because the overall quality of the published clinical trials is low, two new randomized, double-blind, placebo-controlled clinical trials are currently underway in the United States. To date, only one standardized black cohosh extract has been tested clinically; the current recommended dose is 40-80 mg per day. At least 4-12 weeks of treatment may be required before any therapeutic benefits may be apparent. Adverse reactions such as nausea, vomiting, headaches, dizziness, mastalgia, and weight gain have been observed in clinical trials. No drug interactions are reported in the medical literature. The estrogenic effects of black cohosh are controversial, and the more recent data indicate that black cohosh extracts may have an anti-estrogenic activity. Owing to potential effects on sex hormones, however, black cohosh should not be administered to children or during pregnancy and lactation.