Isopimpinellin

246.22

246.22

20GCF755G6

401288|217988

DTXSID30197457

Light yellow fibers

2932202000

57.9

1.9

Solid

1.4±0.1 g/cm3

151 °C

448.7°C at 760 mmHg

225.1±28.7 °C

1.612

In water, 315.3 mg/L at 25 °C (est)

2-8°C

6.8X10-7 mm Hg at 25 °C (est)

Odorless

Henry's Law constant = 2.4X10-9 atm-cu m/mole at 25 °C (est)

146.5 Ų [M+H]+ [CCS Type: TW, Method: calibrated with polyalanine and drug standards]

UN 2811 6.1 / PGII

3

20/21/22-28

22-36/37/39-45-36/37-28

LV1049200

T+

Stable under recommended storage conditions.

P264-P301 + P310

H300

SRP: Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in air, soil or water; effects on animal, aquatic and plant life; and conformance with environmental and public health regulations. If it is possible or reasonable use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination.|Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber; Contaminated packaging: Dispose of as unused product.

Incompatible materials: Strong oxidizing agents.

|Danger|H300: Fatal if swallowed [Danger Acute toxicity, oral]|P264, P270, P301+P310, P321, P330, P405, and P501

Eye/face protection: Face shield and safety glasses. Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).|Skin protection: Handle with gloves.|Body Protection: Complete suit protecting against chemicals. The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.|Respiratory protection: Where risk assessment shows air-purifying respirators are appropriate use a fullface particle respirator type N100 (US) or type P3 (EN 143) respirator cartridges as a backup to engineering controls. If the respirator is the sole means of protection, use a full-face supplied air respirator. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.|Advice for firefighters: Wear self-contained breathing apparatus for firefighting if necessary.

Accidental release measures: Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.

Accidental release measures: Personal precautions, protective equipment and emergency procedures: Wear respiratory protection. Avoid dust formation. Avoid breathing vapors, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains.|Precautions for safe handling: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed.|Appropriate engineering controls: Avoid contact with skin, eyes and clothing. Wash hands before breaks and immediately after handling the product.|Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.|SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.

IDENTIFICATION AND USE: Isopimpinellin is a coumarin derivative isolated from Cnidii Monnieri Fructus extract. It has been tested as an experimental chemopreventive therapy. HUMAN STUDIES: Isopimpinellin inhibited mouse, but not human coumarin 7-hydroxylase (COH) activity. ANIMAL STUDIES: Isopimpinellin was reported to cause persistent photoirritant reactions in mice. However, synthetic isopimpinellin, confirmed to contain as impurities only trace quantities of bergapten (5-methoxypsoralen) and xanthotoxin (8-methoxypsoralen), was not phototoxic when tested in a chick skin bioassay system. These findings are at variance with earlier studies showing isopimpinellin to be phototoxic against chick skin and support the conclusion that isopimpinellin is photobiologically inactive. Several other reports of isopimpinellin photoactivity are most likely attributable to contamination by small amounts of highly active psoralens such as bergapten or xanthotoxin. Isopimpinellin inhibited mouse coumarin 7-hydroxylase (COH) activity both in vitro and in vivo.

Several naturally occurring coumarins previously found to be potent inhibitors of mouse hepatic ethoxyresorufin-O-deethylase (EROD) and/or pentoxyresorufin-O-dealkylase (PROD) were examined for their effects on formation of benzo[a]pyrene (B[a]P) and 7,12-dimethylbenz[a]anthracene (DMBA) DNA adducts in mouse epidermis, as well as, their effects on skin tumor initiation by these polycyclic aromatic hydrocarbons (PAH). Bergamottin, a potent inhibitor of hepatic EROD, given topically 5 min prior to an initiating dose of B[a]P, significantly decreased total covalent binding of B[a]P to DNA in a dose-dependent manner 24 hr after treatment. A dose of 400 nmol bergamottin reduced covalent binding of B[a]P by 72%. Coriandrin, at a dose of 400 nmol also significantly reduced total covalent binding of B[a]P by 59%. In addition, formation of the major (+)anti-B[a]P-diol epoxide-N2-dGuo adduct was selectively reduced by both of these coumarins. In contrast, bergamottin and coriandrin did not significantly decrease covalent binding of DMBA to epidermal DNA at doses of either 400 nmol or 800 nmol. Imperatorin and isopimpinellin, which are more potent inhibitors of hepatic PROD activity, significantly reduced overall binding of DMBA to epidermal DNA by 67% and 52%, respectively, when applied at doses of 400 nmol. These two coumarins also inhibited B[a]P-DNA adduct formation at similar doses but to a lesser extent. Imperatorin at a dose of 400 nmol dramatically decreased formation of covalent DNA adducts derived from both the anti and syn diol epoxides of DMBA. Bergamottin was a potent inhibitor of tumor initiation by B[a]P while coriandrin was less effective in this regard. Imperatorin was an effective inhibitor of skin tumor initiation by DMBA and also inhibited complete carcinogenesis by this PAH. At dose levels higher than those effective against DMBA, imperatorin also inhibited tumor initiation by B[a]P. The results demonstrate that several naturally occurring coumarins possess the ability to block DNA adduct formation and tumor initiation by PAHs such as B[a]P and DMBA. The mechanism for reduced DNA adduct formation and tumor initiation appears to involve inhibition of the P450s involved in the metabolic activation of these hydrocarbons. Finally, the differential effects of certain coumarins on B[a]P vs DMBA DNA adduct formation and tumor initiation may be useful for dissecting the role of specific cytochromes P450 in their metabolic activation.|Naturally occurring coumarins (NOCs) inhibit polycyclic aromatic hydrocarbon-induced skin tumor initiation in mice by blocking cytochrome P450 (P450)-mediated bioactivation of benzo[a]pyrene (B[a]P) and 7,12-dimethylbenz[a]anthracene (DMBA). Bergamottin selectively inhibits tumor initiation by B[a]P, whereas imperatorin and isopimpinellin inhibit tumor initiation with both carcinogens. The goals of the current study were to examine the ability of NOCs to inhibit human P450s in vitro and to establish whether NOCs, which are anticarcinogenic in mice, can block carcinogen bioactivation in cultured human cells. For the initial experiments, incubations containing 5 uM P450, P450 substrate, an NADPH generating system, and NOCs were used to determine the concentrations of each inhibitor that blocked 50% of P450 activity (IC(50)). These results confirmed that NOCs are capable of inhibiting multiple human P450s and that they exhibit selectivity for certain isoforms of human P450s. In subsequent experiments, we examined the effects of bergamottin, imperatorin, and isopimpinellin on DMBA and B[a]P DNA adduct formation in the human breast MCF-7 adenocarcinoma cell line. Coincubation of cells with the three different NOCs significantly inhibited DMBA DNA adduct formation by 29-82% at doses ranging from 2 to 10 uM and significantly inhibited B[a]P DNA adduct formation by 37-80% at doses ranging from 20 to 80 uM. HPLC analysis of the DNA hydrolysates demonstrated that inhibition of DNA adducts corresponded to inhibition of the major B[a]P and DMBA diol-epoxide-derived adducts. Although bergamottin was not effective at blocking DMBA bioactivation in the mouse skin model, it was similar in effectiveness to imperatorin and isopimpinellin in MCF-7 cells. These results demonstrate that NOCs, which are present in citrus fruits and other components of the human diet, are capable of inhibiting carcinogen metabolizing enzymes and blocking bioactivation of both B[a]P and DMBA in MCF-7 cells.|Naturally occurring coumarins (NOCs) are anti-carcinogenic in the mouse skin model. To characterize the chemopreventive potential of NOCs against breast cancer, we first examined their effects on 7,12-dimethylbenz[a]anthracene (DMBA)-DNA adduct formation in mouse mammary gland. We hypothesized that those NOCs that both inhibited cytochrome P450 1A1/1B1 and induced hepatic glutathione S-transferases (GSTs) would be the most effective in blocking DMBA-DNA adduct formation in mouse mammary gland. To address this hypothesis, simple coumarins (e.g. coumarin and limettin, which induced mouse hepatic GSTs but had little effect on P4501A1/1B1) and linear furanocoumarins (e.g. imperatorin and isopimpinellin, which induced hepatic GSTs and were potent inhibitors of P4501A1/1B1) were compared. Mice were pretreated with NOCs (150 mg/kg body wt, by gavage) prior to either a single dose of DMBA (50 ug) or multiple doses of DMBA (20 ug daily for 3 and 6 weeks). Mammary DMBA-DNA adduct formation was quantitated by the nuclease P1-enhanced 32P-postlabeling assay. With the single dose of DMBA, coumarin, limettin, imperatorin and isopimpinellin inhibited DMBA-DNA adduct formation by 50, 41, 79 and 88%, respectively. Coumarin, limettin and imperatorin blocked DMBA-DNA adduct formation by 36, 60, and 66% at 3 weeks, and by 0, 49 and 55% at 6 weeks of DMBA dosing, respectively. In a 6 week dose-response study of select NOCs and 7,8-benzoflavone (a potent P4501 inhibitor that had little effect on GSTs), DMBA-DNA adduct formation was inhibited by 0, 43 and 24% in the limettin groups; by 26, 26 and 69% in the isopimpinellin groups; and by 80, 96 and 97% in the 7,8- benzoflavone groups at 35, 70 and 150 mg/kg, respectively. Taken together, these results suggest that linear furanocoumarins had a greater inhibitory effect on DMBA-DNA adduct formation in mouse mammary glands compared with simple coumarins, and that the predominant effect may be P4501 inhibition.|The current study was designed to determine the mechanistic basis for differences in the effects of naturally occurring furanocoumarins on skin tumor initiation by 7,12-dimethylbenz[a]anthracene (DMBA). Female SENCAR mice were pretreated topically with bergamottin, imperatorin, or isopimpinellin (100-3200 nmol), 7,8-benzoflavone (7,8-BF, 5-40 nmol, a known inhibitor of DMBA skin carcinogenesis in mice), or acetone (vehicle control) 5 min prior to topical treatment with DMBA (10 nmol). Imperatorin, isopimpinellin, and 7,8-BF, but not bergamottin, significantly blocked total DMBA-DNA adduct formation. HPLC analysis of DNA adducts revealed that bergamottin preferentially inhibited formation of anti-DMBA diol-epoxide (DMBADE) derived DNA adducts, imperatorin, and isopimpinellin inhibited both anti- and syn- derived adducts, whereas 7,8-BF showed some selectivity for reduction of syn-DMBADE-DNA adducts. Mouse embryo fibroblast C3H/10T1/2 (10T1/2) cells, and mouse hepatoma-derived 1c1c7 (Hepa-1) cells, which preferentially express P450 1b1 and P450 1a1, respectively, were co-incubated with 2 uM bergamottin, imperatorin, isopimpinellin, and 7,8-BF, and with DMBA (2 uM). Hepa-1 cells (P450 1a1) formed mainly anti-DMBADE-DNA adducts. In contrast, 10T1/2 cells (P450 1b1) formed mainly syn-DMBADE-DNA adducts. Bergamottin inhibited DMBA metabolism to DMBA-3,4-diol and blocked DNA adduct formation in Hepa-1 cells, but had little effect in 10T1/2 cells. In contrast, 7,8-BF completely blocked DMBA metabolism and DNA adduct formation in 10T1/2 cells, but had little effect in Hepa-1 cells. Imperatorin and isopimpinellin inhibited DMBA bioactivation in both cell lines. These results indicate that bergamottin is a more selective inhibitor of P450 1a1 and overall a less effective inhibitor of the metabolic activation of DMBA in mouse epidermis. In contrast, imperatorin, isopimpinellin, and especially 7,8-BF, which block metabolic activation of DMBA in mouse epidermis, appear more selective for P450 1b1. On the basis of our studies using 10T1/2 cells and Hepa-1 cells, it appears that P450 1a1 is primarily responsible for converting DMBA-3,4-diol to anti-DMBADE, whereas P450 1b1 is primarily responsible for converting DMBA-3,4-diol to syn-DMBADE. These data demonstrate the role of P450 1a1 and 1b1 in the metabolic activation of DMBA in mouse epidermis and provide a mechanistic explanation for the differential effects of naturally occurring furanocoumarins (and 7,8-BF) on polycyclic aromatic hydrocarbon skin carcinogenesis.

Coumarin derivative isolated from Cnidii Monnieri Fructus extract.

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 320(SRC), determined from a structure estimation method(2), indicates that isopimpinellin is expected to have moderate mobility in soil(SRC). Volatilization of isopimpinellin from moist soil surfaces is not expected(SRC) given an estimated Henry's Law constant of 2.4X10-9 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). Isopimpinellin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 6.8X10-7 mm Hg at 25 °C(SRC), determined from a fragment constant method(2). Biodegradation data in soil were not available(SRC, 2019).|AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 320(SRC), determined from a structure estimation method(2), indicates that isopimpinellin is expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 2.4X10-9 atm-cu m/mole(SRC), developed using a fragment constant estimation method(2). Isopimpinellin is expected to undergo hydrolysis in the environment due to the presence of functional groups that hydrolyze under environmental conditions(3). According to a classification scheme(4), an estimated BCF of 14(SRC), from an estimated log Kow of 2.22(2) and a regression-derived equation(2), suggests the potential for bioconcentration in aquatic organisms is low. Biodegradation data in water were not available(SRC, 2019).|ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), isopimpinellin, which has an estimated vapor pressure of 6.8X10-7 mm Hg at 25 °C(SRC), determined from a fragment constant method(2), is expected to exist solely in the particulate phase in the ambient atmosphere. Particulate-phase isopimpinellin may be removed from the air by wet and dry deposition(SRC). Isopimpinellin has a light absorption peak at 313 nm(3) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).

The lactone ring in analogous isopsoralen is susceptible to alkaline hydrolysis(1); therefore, isopimpinellin may undergo hydrolysis under alkaline environmental conditions(SRC). Isopimpinellin has a light absorption peak at 313 nm(2) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).

An estimated BCF of 14 was calculated in fish for isopimpinellin(SRC), using an estimated log Kow of 2.22(1) and a regression-derived equation(1). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low.

Using a structure estimation method based on molecular connectivity indices(1), the Koc of isopimpinellin can be estimated to be 320(SRC). According to a classification scheme(2), this estimated Koc value suggests that isopimpinellin is expected to have moderate mobility in soil(SRC).

The Henry's Law constant for isopimpinellin is estimated as 2.4X10-9 atm-cu m/mole(SRC) using a fragment constant estimation method(1). This Henry's Law constant indicates that isopimpinellin is expected to be essentially nonvolatile from water and moist soil surfaces(2). Isopimpinellin is not expected to volatilize from dry soil surfaces(SRC) based upon an estimated vapor pressure of 6.8X10-7 mm Hg(SRC), determined from a fragment constant method(1).

Isopimpinellin was detected in 12 industrial cold-pressed key and Persian lime oils at 350-365 and 169-293 mg/100 g of oil, respectively(1). Lime oil contained 7422 mg/L of isopimpinellin, it was not detected (detection limit 0.026 mg/L) in lemon, bergamot, grapefruit, mandarin or bitter orange oils(2). Isopimpinellin was detected at 1.4 mg/kg fresh weight in clementine peel extract, at a trace in lemon, grapefruit, bergamot and pummelo peel extracts, but not detected (detection limit 0.03 mg/kg fresh weight) in orange peel extract(3).

Occupational exposure may be limited to dermal exposure where plants that contain isopimpinellin are processed. Monitoring data indicate that the general population may be exposed to isopimpinellin via ingestion of food containing isopimpinellin. (SRC)

/EXPL THER/ OBJECTIVE: To screen antitumor active compounds, drug-like or leading compounds from Chinese traditional and herbal drugs. METHODS: Eleven coumarin compounds isolated from the Chinese traditional and herbal drugs were studied for their antitumor activities in vitro by determining the inhibition rates against growth of human bladder carcinoma cell line E-J. RESULTS: It showed that umbelliferone, scoparone, demethylfuropinarine, isopimpinellin, forbesoside, columbianadin, decursin and glycycoumarin inhibited the growth of human bladder carcinoma cell line E-J in vitro and their activities showed a concentration-effect relationship. The inhibitory effects of forbesoside, columbianadin, decursin and umbelliferone, with IC50 values of 7.50x10(-7), 2.30x10(-6), 6.00x10(-6) and 1.30x10(-6) mol/L, respectively, were stronger than those of the other tested compounds. However, xanthotoxin, esculin and sphondin did not inhibit the growth of human bladder carcinoma cell line E-J in this assay condition. CONCLUSION: These findings indicate that forbesoside, columbianadin, esculin, decursin and umbelliferone would be effective or regarded as potent drug-like or leading compounds against human bladder carcinoma.|/EXPL THER/ Several naturally occurring coumarins, to which humans are routinely exposed in the diet, were previously found to inhibit P450-mediated metabolism of benzo[a]pyrene (B[a]P) and 7,12-dimethylbenz[a]anthracene (DMBA) in vitro, block DNA adduct formation in mouse epidermis and inhibit skin tumor initiation by B[a]P and/or DMBA when applied topically to mice. The present study was designed to investigate the effects of two of these compounds, of the linear furanocoumarin type, when given orally (70 mg/kg per os, four successive daily doses), on P450 and glutathione S-transferase (GST) activities and DNA adduct formation by B[a]P and DMBA in various mouse tissues. Imperatorin and isopimpinellin significantly blocked ethoxyresorufin O-deethylase (EROD) and pentoxyresorufin O:-dealkylase (PROD) activities in epidermis at 1 and 24 hr after oral dosing. Imperatorin and isopimpinellin modestly inhibited EROD activities in lung and forestomach at 1 hr and significantly inhibited PROD activities in lung and forestomach at 1 hr after the final oral dose. Twenty-four hours after the final oral dose of imperatorin or isopimpinellin EROD and PROD activities remained inhibited in epidermis and lung. However, forestomach P450 activity had returned to control levels. Interestingly, imperatorin and isopimpinellin treatment inhibited liver EROD activity at 1 hr, had no effect on PROD activity at this time point, but elevated both these enzyme activities at 24 hr. Elevated EROD and PROD activities coincided with elevated hepatic P450 content. Imperatorin and isopimpinellin treatment also increased liver cytosolic GST activity at both 1 and 24 hr after the final oral dose by 1.6-fold compared with corn oil controls. Oral administration of imperatorin and isopimpinellin also had a protective effect against DNA adduct formation by B[a]P and DMBA. Imperatorin pretreatment decreased formation of DNA adducts by DMBA in forestomach. Pretreatment with isopimpinellin led to reduced DNA adduct levels in liver (B[a]P), lung (B[a]P) and mammary epithelial cells (DMBA). These results suggest that imperatorin and isopimpinellin may have potential chemopreventive effects when administered in the diet.|/EXPL THER/ The current study was designed to evaluate the effects of oral administration of the citrus coumarin, isopimpinellin, on skin tumor initiation by topically applied benzo[a]pyrene (B[a]P) and 7,12-dimethylbenz[a]anthracene (DMBA). To evaluate the effects of orally administered isopimpinellin on skin tumor initiation by B[a]P and DMBA, its effects on DNA adduct formation were first evaluated. Female SENCAR mice were pre-treated twice with corn oil, or isopimpinellin (70 mg/kg body wt per os) at 24 hr and 2 hr prior to topical treatment with B[a]P or DMBA. Another citrus coumarin, imperatorin, was also included in these experiments for comparison. Orally administered isopimpinellin and imperatorin significantly inhibited B[a]P-DNA adduct formation by 37 and 26%, respectively. Imperatorin also blocked DMBA-DNA adduct formation by 43%. In a second dose-response study, orally administered isopimpinellin(35, 70 and 150 mg/kg) blocked DMBA-DNA adduct formation by 23, 56 and 69%, respectively. For the tumor study, mice were pretreated orally with corn oil or isopimpinellin at 24 and 2 hr prior to initiation with DMBA, and 2 weeks later promotion began with 12-O-tetradecanoylphorbol-13-acetate (TPA). Isopimpinellin significantly reduced the mean number of papillomas per mouse by 49, 73 and 78% compared to corn oil controls at 30, 70 and 150 mg/kg body wt, respectively. Orally administered isopimpinellin also significantly reduced the percentage of mice with papillomas at the highest dose tested (150 mg/kg). The effectiveness of isopimpinellin given topically over a broad dose range against DMBA tumor initiation was also evaluated for comparison. As part of this study, several parameters of systemic toxicity were evaluated following oral dosing with isopimpinellin and imperatorin. Mice were treated orally with corn oil, isopimpinellin or imperatorin (35, 70 and 150 mg/kg body wt per os) once daily for four consecutive days, killed at 24 hr after the last dose, and livers, lungs, and kidneys evaluated histologically. In addition, urinary parameters of nephrotoxicity, blood parameters of liver and kidney function, and thrombin clotting time were assayed. No significant changes in blood clotting, or renal or hepatic function were observed. There was, however, a significant increase in liver wt accompanied by cytoplasmic vacuolation of hepatocytes. There were no histopathological changes in lungs or kidneys. Overall, these data indicate that isopimpinellin (and imperatorin) have chemopreventive effects when administered orally on skin tumor initiation by DMBA.

Cytochromes P450 (P450s) and glutathione S-transferases (GSTs) constitute two important enzyme families involved in carcinogen metabolism. Generally, P450s play activation or detoxifying roles while GSTs act primarily as detoxifying enzymes. We previously demonstrated that oral administration of the linear furanocoumarins, isopimpinellin and imperatorin, modulated P450 and GST activities in various tissues of mice. The purpose of the present study was to compare a broader range of naturally occurring coumarins (simple coumarins, and furanocoumarins of the linear and angular type) for their abilities to modulate hepatic drug-metabolizing enzymes when administered orally to mice. We now report that all of the different coumarins tested (coumarin, limettin, auraptene, angelicin, bergamottin, imperatorin and isopimpinellin) induced hepatic GST activities, whereas the linear furanocoumarins possessed the greatest abilities to induce hepatic P450 activities, in particular P450 2B and 3A. In both cases, this corresponded to an increase in protein expression of the enzymes. Induction of P4502B10, 3A11, and 2C9 by xenobiotics often is a result of activation of the pregnane X receptor (PXR) and/or constitutive androstane receptor (CAR). Using a pregnane X receptor reporter system, our results demonstrated that isopimpinellin activated both PXR and its human ortholog SXR by recruiting coactivator SRC-1 in transfected cells. In CAR transfection assays, isopimpinellin counteracted the inhibitory effect of androstanol on full-length mCAR, a Gal4-mCAR ligand-binding domain fusion, and restored coactivator binding. Orally administered isopimpinellin induced hepatic mRNA expression of Cyp2b10, Cyp3a11, and GSTain CAR(+/+) wild-type mice. In contrast, the induction of Cyp2b10 mRNA by isopimpinellin was attenuated in the CAR(-/-) mice, suggesting that isopimpinellin induces Cyp2b10 via the CAR receptor. Overall, the current data indicate that naturally occurring coumarins have diverse activities in terms of inducing various xenobiotic metabolizing enzymes based on their chemical structure.

Synthetic isopimpinellin (5,8-dimethoxypsoralen), confirmed to contain as impurities only trace quantities at most of psoralen, bergapten (5-methoxypsoralen) and xanthotoxin (8-methoxypsoralen), is not phototoxic when tested in a chick skin bioassay system. These findings are at variance with earlier studies showing isopimpinellin to be phototoxic against chick skin and support the conclusion that isopimpinellin is photobiologically inactive. As recently proposed by others, the several reports of isopimpinellin photoactivity are most likely attributable to contamination by small amounts of highly active psoralens such as bergapten or xanthotoxin.

/SRP:/ Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR if necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Poisons A and B/|/SRP:/ Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if needed. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 mL/kg up to 200 mL of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool ... . Cover skin burns with dry sterile dressings after decontamination ... . /Poisons A and B/|/SRP:/ Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Consider administering a beta agonist such as albuterol for severe bronchospasm ... . Monitor cardiac rhythm and treat arrhythmias as necessary ... . Start IV administration of D5W TKO /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Watch for signs of fluid overload ... . Treat seizures with diazepam (Valium) or lorazepam (Ativan) ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Poisons A and B/

/HUMAN EXPOSURE STUDIES/ Isolation of the furocoumarins (psoralens) bergapten, isobergapten, sphondin, isopimpinellin and pimpinellin from the Umbilliferous plant Heracleum laciniatum was carried out by column chromatography, and the structure and absorption spectra for the 5 furocoumarins isolated are described. Photoepicutaneous testing showed the strongest phototoxic effects from bergapten, marked effects from pimpinellin, weak effects from sphondin and none from the others. These in vivo findings were confirmed by the in vitro Candida test. Action spectrum studies demonstrated peak photosensitivity in the range 330-335 nm, bergapten being more than twice as phototoxic as pimpinellin.|/ALTERNATIVE and IN VITRO TESTS/ Coumarin is 7-hydroxylated by the P450 isoform Cyp2a-5 in mice and CYP2A6 in humans. Various drugs, endogenous substances, plant substances and carcinogens, altogether about 90 chemicals, were evaluated as possible inhibitors of coumarin 7-hydroxylase (COH) activity in mouse microsomes. The effects of selected compounds on COH activity in human liver microsomes were also tested. The furanocoumarin derivatives methoxsalen (8-methoxypsoralen) and psoralen proved to be the most potent inhibitors of mouse COH activity (IC50 values 1.0 and 3.1 uM, respectively). The furanocoumarins bergapten (5-methoxypsoralen), isopimpinellin (5,8-dimethoxypsoralen), imperatorin and sphondin also effectively inhibited mouse COH activity (IC50 values 19-40 uM). Methoxsalen, isopimpinellin and metyrapone were also inhibitors in mice in vivo. Methoxsalen was a potent inhibitor of COH activity also in human liver microsomes, (IC50 value 5.4 uM), whereas bergapten, isopimpinellin and imperatorin had no effect. The imidazole antimycotic miconazole was a potent but non-specific inhibitor of COH activity. Several known substrates and inhibitors of members in the CYP1A, CYP2B, CYP2C, CYP2D and CYP3A subfamilies were poor inhibitors of COH activity. These results suggest that (i) the coumarin-type compounds in particular interact with the active sites of Cyp2a-5 and CYP2A6, and (ii) the active sites of Cyp2a-5 and CYP2A6 are structurally different, since a number of compounds inhibited mouse, but not human COH activity.

5,8-dimethoxypsoralen

Radix Angelicae dahuricae is a well-known medicinal herb in a number of herb preparations for medical uses. In this study, a rapid and selective method using liquid chromatography with tandem mass spectrometry was developed for the separation and simultaneous quantitation of nine furanocoumarins from Radix A. dahuricae, namely imperatorin, isoimperatorin, oxypeucedanin hydrate, bergapten, oxypeucedanin, xanthotoxol, xanthotoxin, isopimpinellin, and psoralen. Chromatographic separation was achieved on a CAPCELL PAK MG II C18 analytical column. Detection was performed using positive electrospray ion source in the multiple reaction monitoring mode. The method was fully validated for analyzing these principles in rat plasma with a lower limit of quantification from 0.5 to 5 ng/mL. The intra- and interbatch precisions were less than 10%, and the accuracies ranged from -7.5 to 8.0%. The extraction recovery of the analytes was above 70% without a significant matrix effect. The method was used to determine the oral and intravenous pharmacokinetic profiles of these furanocoumarins after dosing with Radix A. dahurica extract. The bioavailability of these furanocoumarins ranged from 10.1 to 82.8%. These data provide critical information for a better understanding of the pharmacological mechanisms and herb-drug interaction potential of Radix A. dahurica.

A highly selective and sensitive method for simultaneous quantitation of osthole, bergapten and isopimpinellin in rat plasma and tissues was developed by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). After liquid-liquid extraction of samples with methyl tert-butyl ether, the analytes and dextrorphan (internal standard, IS) were separated by a Hypersil GOLD AQ C18 column with gradient elution of acetonitrile and water containing 0.5 per mil formic acid. Three determinands were detected using an electrospray ionization (ESI) tandem mass spectrometry in the multiple reaction monitoring (MRM) modes with positive electrospray ionization. Calibration curves were recovered over the concentration ranges of 1-200 ng/mL, 1-500 ng/mL, 0.25-200 ng/mL for osthole, bergapten and isopimpinellin in plasma; 1-100 ng/mL, 1-500 ng/mL, 0.5-100 ng/mL for osthole, bergapten and isopimpinellin in tissues, respectively. The intra-day precision (R.S.D.) was within 13.90% and the intra-day accuracy (R.E.) was within -6.27 to 6.84% in all biological matrixes. The inter-day precision (R.S.D.) was less than 13.66% and the inter-day accuracy (R.E.) was within -10.64 to 13.04%. Then the method was successfully applied to investigate plasma pharmacokinetic study and tissue distribution of osthole, bergapten and isopimpinellin in rats after oral administration of Fructus Cnidii extraction, especially for testis/uterus tissue distribution. The results demonstrated that osthole, bergapten and isopimpinellin were absorbed and eliminated rapidly with wide distributions in rats. Distribution data of these three bioactive components in testis/uterus tissues could offer useful information for the further preclinical and clinical studies of Fructus Cnidii in the treatment of genital system disease.