Perforatum Extract Research Articles

Abstract A46: Pseudohypericin in Hypericum perforatum inhibited LPS-stimulated PGE2 and NO in mouse macrophages by potentiating SOCS3 expression

Abstract Introduction: Hypericum perforatum, also known as ‘St. John's wort’, is one of the most studied medicinal plants. Despite its primary use as an anti-depression agent, certain compounds such as hypericin and hyperforin in H. perforatum extract have been shown to inhibit tumor growth by inducing apoptosis/necrosis and inhibiting angiogenesis. Using hypericin in photodynamic cancer therapy is also being studied. Our previous studies have demonstrated that H. perforatum extract and a group of 4 compounds in it, namely pseudohypericin, amentoflavone, quercetin, and chlorogenic acid, decreased lipopolysaccharide (LPS)-stimulated macrophage inflammatory response, and identified the activation of suppressor of cytokine signaling 3 (SOCS3) as a candidate mechanism for this activity. Given that both inflammation and SOCS3 suppression are associated with tumor progression, we studied the role of SOCS3 activation in the anti-inflammatory activity of H. perforatum extract and its components. Methods: Specific siRNA was used to knockdown the expression of SOCS3 in RAW 264.7 mouse macrophages. Activation of SOCS3 in macrophages was measured at mRNA and protein levels using qRT-PCR and Western blot. H. perforatum extract at 30 µg/mL, the 4 compounds at the same concentrations as in the extract, and the combinations of individual compounds were applied to macrophages with and without SOCS3 knockdown to reveal whether their inhibition of LPS-stimulated prostaglandin E2 (PGE2) and nitric oxide (NO) was dependent on SOCS3. Results: SOCS3 expression in the mouse macrophages was activated upon LPS stimulation and further potentiated by H. perforatum extract and the 4 compounds studied. SOCS3 siRNA transfection significantly compromised the activation of SOCS3. H. perforatum extract and the 4 compounds reduced LPS-stimulated PGE2 and NO production, but only the inhibitory effect of the 4 compounds was negated by SOCS3 knockdown. Combinations of two or three of the 4 compounds that include pseudohypericin, the most essential component among the four that act synergistically in reducing macrophage inflammatory response, lost their inhibitory effect on PGE2 and NO production in SOCS3 knockdown cells. Conclusions: SOCS3 activation was critical for pseudohypericin's independent and interactive anti-inflammatory activity with amentoflavone, quercetin, and chlorogenic acid. H. perforatum extract utilized alternative mechanisms that are SOCS3 independent to inhibit macrophage inflammation. In addition to light-activated cytotoxicity and inhibition of angiogenesis, magnification of SOCS3 activation by H. perforatum extract might contribute to its anti-tumor potential. Citation Information: Cancer Prev Res 2010;3(12 Suppl):A46.

The Study of Hypericum perforatum extract on wound healing in rabbit

Wound healing is a natural reaction to injury witch results in restoration of tissue integrity. Repair consists of four phases: inflammation, re-epithelialization, angiogenesis, fibroblast recruitment and scarring. In this study the healig effect of Hypericum perforatum extract was investigated on open wound. Hydroalcoholic extract of Hypericum P. was prepared by maceration method. Newzeland rabbits of either sexes weighting 1.6-2.5 kg were used. Method of Cross et al (1995) was used to perform excisional wound. Hairs of lower back and left flank of animal was carefully shaved and cleaned. Animal was held in standard crouching position. A template measuring 20×20 mm was placed on the skin and the outline traced using a fixed-tipped pen. Desired area was locally anasthetised with lidocaine 2%. Full thickness wound was made by excising the skin using a scalped blade and forceps. Every day the outline of each wound was traced by using a transparent plastic sheet. Treatment of wounds started from the first moments, twice daily. In other to minimize the errors, measurment was repeated three times. Then area of wounds was calculated by mm chart paper. Wound of bland group were left untreated. Second group was treated with eucerin as placebo control, in third group phenytion cream 1% was used as standard control and in other groups different concentration of hypericum extract 2%, 5%, and 10% w/w in eucerin base were adminstrated twice daily. Area of wound in the first day was considerd as 100% and area of subequent days were compared with initial day. Percentage of healing was calculared by substracting the percentage of area from 100. Healing of eucerin and phenytoin groups lasted 21 and 158 day respectively. Healing in Hypericum cream of 2%, 5% and 10% groups lasted 14, 15 and 16 days respectively. Best results obtained with 2% extract. The result of this study confirms that Hypericum cream 2% had the best wound healing effect even better than phenytion cream, however the Hypericum Cream 5% & 10% had good and noticeable effect too.

Gastroprotective activity of Hypericum perforatum extracts prepared with different vegetable oils

Gastroprotective activity of Hypericum perforatum extracts prepared with different vegetable oils

Inhibition of 17β-estradiol activation by CYP1A1: Genotype- and regioselective inhibition by St. John's Wort and several natural polyphenols

Several epidemiological studies associate certain CYP1A1 genotypes, alone or in combination, with an increased risk of estrogen-related cancers. Previously we demonstrated that metabolic activation of estrogens by CYP1A1 is a genotype-dependent reaction with the CYP1A1.2 (Ile462Val) variant being the most efficient catalyst (Kisselev et al.). To answer the question whether genotype-dependent inhibition of activation of estrogens by CYP1A1 could also contribute, we studied the inhibition of hydroxylation activity of the most common allelic variants of human CYP1A1 towards 17β-estradiol. We expressed and purified CYP1A1.1 (wild-type), CYP1A1.2 (Ile462Val), and CYP1A1.4 (Thr461Asn) and performed inhibition assays by natural polyphenols of our diet and drugs of NADPH-dependent estradiol hydroxylation in reconstituted CYP1A1 systems. From the polyphenols studied, a St. John's Wort ( Hypericum perforatum) extract, some of its main single constituents hypericin, pseudohypericin, and quercetin, as well as the flavonols kaempferol, myricetin and the phytoestrogens resveratrol and tetramethyl-stilbene exhibited strong inhibition. For the St. John's Wort extract and its single constituents hypericin, pseudohypericin, and quercetin, inhibition exhibited a remarkable dependency on the CYP1A1 genotype. Whereas (wild-type) CYP1A1.1 was most inhibited by the whole crude extract, the variant CYP1A1.2 (Ile462Val) was significantly stronger inhibited by the constituents in its pure form: IC 50 values for 2-hydroxylation was more than two times lower compared with the wild-type enzyme and the variant CYP1A1.4 (Thr461Asn). Besides this, the inhibition exhibited a remarkable regioselectivity. The data suggest that risk of estrogen-mediated diseases might be not only influenced by CYP1A1 genotype-dependent activation but also its inhibition by natural polyphenols of our diet and drugs.

Pharmacological studies on Hypericum perforatum fractions and constituents

Context: This study describes the antispasmodic, bronchodilator, and cardiovascular-modulatory activities of Hypericum perforatum Linn. (Hypericaceae) fractions and constituents.Aim of study: Pharmacological investigation of H. perforatum fractions and active principles.Materials and methods: H. perforatum extract fractions [petroleum spirit (HpPet), chloroform (HpCHCl3), ethyl acetate (HpEtAc), and aqueous (HpAq)] and its compounds (hyperforin, hypericin, and hyperoside) were studied in various isolated tissue preparations.Results: In rabbit jejunum, HpCHCl3, HpEtAc and HpAq, like papaverine, inhibited both spontaneous and K+ (80 mM)-induced contractions at similar concentrations, whereas HpPet was relatively potent against K+, as verapamil. All fractions caused rightward of Ca2+ concentration-response curves (CRCs), similar to verapamil. HpCHCl3, HpEtAc, and HpAq shifted isoprenaline-inhibitory CRCs to left, like papaverine, while HpPet was devoid of any such effect, as verapamil. In guinea-pig trachea, HpCHCl3, HpEtAc, and HpAq equipotently relaxed carbachol and K+-induced contractions and shifted the isoprenaline-curves to the left, whereas HpPet was more effective against K+, without potentiating isoprenaline effect. When tested in rabbit aorta, all fractions exhibited vasoconstrictor and vasodilator effects, except HpEtAc, which did not produce vasoconstriction. In guinea-pig atria HpCHCl3, HpEtAc, and HpAq initially caused cardiac stimulation, followed by inhibition, similar to papaverine, whereas HpPet, like verapamil, caused only cardiac suppression. Hyperforin, hypericin, and hyperoside showed a similar pattern of spasmolytic effect to verapamil.Discussion and conclusion: Thus, all tested fractions of H. perforatum exhibit a combination of Ca2+ antagonist and phosphodiesterase-inhibition, except petroleum spirit which was devoid of later mechanism. The compounds tested showed only Ca2+ channel blocking effect.

Hypericum perforatum extract is as efficacious as imipramine for moderately depressed patients

Hypericum perforatum extract is as efficacious as imipramine for moderately depressed patients

Identification of anti‐inflammatory constituents in Hypericum perforatum and Hypericum gentianoides extracts using mouse macrophages

Ethanol extracts from eleven species and accessions of Hypericum were screened for their inhibitory properties on LPS‐induced prostaglandin E2 (PGE2) and nitric oxide (NO) in RAW264.7 mouse macrophages. All extracts inhibited PGE2 production by 19%–45% at 10 μg/ml compared to vehicle control while all but one extract also decreased NO production by 10%–35%. No cytotoxicity was noted on any extract at 30 μg/ml. Among all extracts, those from H. perforatum and H. gentianoides demonstrated stronger overall inhibitory potency. HPLC analysis of the extracts revealed that H. perforatum extract contained pseudohypericin, amentoflavone, quercetin and chlorogenic acid; previously identified as a ‘4 component system’; while H. gentianoides extract contained acylphloroglucinols including uliginosin A. H. perforatum and H. gentianoides extracts were fractionated using semi‐preparative HPLC and several fractions inhibited both LPS induced PGE2 and NO production dose‐dependently. HPLC analysis of the most active fractions indicated that ‘4 component system’ could be the major contributor to H. perforatum activity and suggested that acylphloroglucinols were potentially involved in H. gentianoides activity. This study demonstrated significant differences between two Hypericum species with regards to anti‐inflammatory compounds and potential mechanism of action, which will be confirmed by further study.Grant Funding Source: P50 AT004155‐06 NCAAM/ODS from NIH

Identification of JAK–STAT pathways as important for the anti-inflammatory activity of a Hypericum perforatum fraction and bioactive constituents in RAW 264.7 mouse macrophages

Hypericum perforatum extracts have been used to treat diseases, including mild-to-moderate depression and inflammatory conditions. It is particularly important to identify which constituents present in the H. perforatum extracts are responsible for its anti-inflammatory activity since consumers are taking H. perforatum preparations to treat inflammation. We used a combination of four putative bioactive constituents, called the 4-component-system that interacted synergistically to explain the light-activated anti-inflammatory activity of an H. perforatum fraction in RAW 264.7 mouse macrophages. We also combined the constituents at concentrations detected in the fraction to identify key molecular targets. LPS was used to model an inflammatory response, and the 4-component-system and H. perforatum fraction were used as treatments that inhibited LPS-induced prostaglandin E 2 (PGE 2) production in RAW 264.7 mouse macrophages in the studies of gene expression profiles. We used Affymetrix genechips, statistical analysis, and quantitative real-time PCR to identify key gene targets of the 4-component-system and the sub-fraction from an H. perforatum ethanol extract. The H. perforatum sub-fraction, with or without LPS stimulation, affected far more genes than the 4-component-system with and without LPS. Genes involved in Janus kinase, as well as a signal transducer and activator of transcription (JAK–STAT) and eicosanoid pathways were identified that could account for the reduction in PGE 2 observed with both treatments in LPS-stimulated macrophages. Ten genes may be particularly important targets for activity of the 4-component-system and the fraction with LPS stimulation and these genes were involved in inflammatory signaling pathways, namely the JAK–STAT and eicosanoid pathways.

A Semiquantitative FIA-ESI-MS Method for the Rapid Screening of Hypericum perforatum Crude Extracts

A method based on FIA-ESI-MS has been developed to profile the major constituents of Hypericum perforatum extracts. The objective was to obtain simultaneous semi-quantitative data on hypericin, chlorogenic acid, rutin, quercitrin, quercetin and hyperforin contents for a high-throughput screening of the raw plant material. The principal drawback of FIA-ESI analysis of complex mixtures involves ion suppression effects: the ionization of some components of the mixture can be severely suppressed by ionization of others. The results show that this problem can be alleviated using a new approach to generate calibration curves.

Comparison of the growth-inhibitory effect of Hypericum perforatum L. extracts, differing in the concentration of phloroglucinols and flavonoids, on leukaemia cells.

In this study we compared, simultaneously, the growth-inhibitory effect of Hypericum perforatum L. extracts, containing various amounts of hyperforin (A 3.25%; B 2.21%; C 0.21% w/w) and flavonoids (A and B 5.3%; C 10% w/w), but closely same amounts of naphthodiantrones (0.3%) on two leukaemic cell lines K562 and U937 in the WST-1 assay. The GI50 (concentration of extracts which caused 50% of cell growth inhibition) for H. perforatum extracts analysed and characterized by HPLC for their biologically active constituents was 248.3-621.3 microg mL(-1) in K562 and 378.2-911.7 microg mL(-1) in U937 cells. The corresponding values of the three main groups were 1.6-3.9 microM naphthodianthrones, 1.0-40.7 microM phloroglucinols and 30.5-68.5 microM flavonoids. The results of this study supported the hypothesis that, apart from hyperforin and flavonoids, other components of the extract could be involved in its growth-inhibitory effect that it exerts without light activation.

Hypericum perforatum extracts as potential antidepressants.

Extracts of Hypericum perforatum have been used in the treatment of mild to moderate depression for many years in Europe. More recently, these extracts have become available in the USA as dietary supplements and have been popularly used to improve mood. In support of this practice, data from several controlled clinical studies suggest that Hypericum perforatum is better than placebo and as effective as established antidepressant drugs. These data have, however, several limitations that should temper our enthusiasm and argue for more research before accepting Hypericum perforatum extracts into our pharmacopoeia of established antidepressants. Extant data on the possible effects of Hypericum perforatum extracts in depression are here critically reviewed and plans for further research presented.

Polyphenol characterization and encapsulation in β-cyclodextrin of a flavonoid-rich Hypericum perforatum (St John's wort) extract

Purified methanolic extracts of Hypericum perforatum (HP) from Northern Greece were very rich in flavonoids. Among simple polyphenols determined by GC–MS, epicatechin, catechin and quercetin predominated, their concentrations being 118.9 ± 20.6, 8.7 ± 1.4 and 5.8 ± 0.8 mg/g extract. LC-MS analysis revealed that the HP extract was mainly consisted of quercetin glucosides, catechin and quercetin. Among anthocyanins, malvidine was present at 1.96 ± 0.2 mg/g. The 1,1-diphenyl-2-picrylhydrazyl radical (DPPH ) and the ferric reducing antioxidant power (FRAP) assays showed that the HP extract exerted significant antioxidant activity. The inclusion complex of HP with β-cyclodextrin ( β-CD) was prepared by mixing 1:4 mass ratios of its components in aqueous media and subsequent freeze-drying. The encapsulation was verified by differential scanning calorimetry (DSC) and NMR studies, and encapsulation efficiencies were 27.5, 30.0 and 35.0% for catechin, epicatechin and quercetin respectively. DSC after thermal oxidation indicated that the inclusion complex remained intact at temperatures where the free HP extract was oxidized. It is concluded that the encapsulation in β-CD improves the thermal stability of nutraceutical antioxidants present in St John's wort extract, suggesting that the inclusion complex could serve as a flavonoids-rich food supplement or a novel additive to enhance the antioxidant capacity of fresh or thermally processed food.

The Effects of Hypericum Perforatum Extract on Topical Burn Injury: A Comparative Study with Iodine

The Effects of Hypericum Perforatum Extract on Topical Burn Injury: A Comparative Study with Iodine

Hypericum perforatum influences stress induced femur mass density decline

Event Abstract Back to Event Hypericum perforatum influences stress induced femur mass density decline Antonia Kotsiou1*, Luke Petrokokkinos2 and Christine Tesseromatis1 1 University of Athens, Pharmacology Department, Greece 2 University of Athens, Medical Physics Laboratory, Greece Introduction. Stress reduce the bones mass. Hypericum perforatum (Hp) is an antidepressive plant remedy (serotonine reuptake inhibitor-SSRI’S). (1)Furthermore Hp contains hypericin, hyperforin, hyperoside and flavonoids that exert oestrogen-mimetic activity(2) The aim of the study was to investigate the discrepancies of femur mass density in Wistar rats submitted to different stress procedures and treated with Hp Material- Methods. 7 groups (A-G) of 7 male Wistar rats of age 5-6 weeks and weight 200±15 g were used. Group A control and groups B,C,D were submitted to forced swiminnig stress 10 days, isolation stress 80 days, electrical stimuli 80 days, respectively. Groups E,F,G were submitted to same stress procedures and treated p.o. with Hypericum perforatum extract 0,5ml/daily (Johanniskraut (1/10 Opea®), equivalent to 1% flavonoids). DEXA of femur bone was measured using a pulsed source dual-energy X-ray absorptiometry apparatus. Results. Bone Parameters during stress and Hypericum perforatum treatment Discussion – Conclusion. Hp antidepressive treatment ameliorated the bone mass status despite the fact that the widely used SSRI’S decrease bone mass. This may be attributed to the Hp flavonoids. Figure 1

Effect of nanohypericum (Hypericum perforatum gold nanoparticles) treatment on restraint stressinduced behavioral and biochemical alteration in male albino mice

Backgorund:Hypericum perforatum extract (HPE), is known for its antidepressant effect.Methods:In the present study we investigated the effect of H. perforatum gold nanoparticles (Nanohypericum-HPGNPs) protective role against restraint stress-induced behavioral and biochemical alterations in mice. Animals were immobilized for a period of 6 hrs/day. HPE (200 mg/kg) and nanohypericum (20 mg/kg) were administered 30 minutes before the animals were subjected to acute immobilized stress. Behavioral test parameters for anxiety and spatial memory were assessed followed by biochemical parmeters (lipid peroxidation, super oxide dismutase, catalase, glutathione peroxidase, reduced glutathione, etc.) subsequently.Results:The behavior study showed severe anxiety and memory loss compared to unstressed animals. Biochemical analyses revealed an increase in lipid per oxidation, depletion of super oxide dismutase, reduced glutathione, catalase activity and glutathione per oxidase as compared to unstressed animal. Twenty one days of H. perforatum and nanohypericum treatment in a dose of 200 mg/kg and 20 mg/kg, respectively, significantly attenuated restraint stress-induced behavioral and oxidative damage.Conclusion:In conclusion nanohypericum prove the modest activity than the HPE.

The inhibitory effect of Hypericum perforatum extract on morphine withdrawal syndrome in rat and comparison with clonidine

The effects of Hypericum perforatum (St John's wort) on morphine withdrawal syndrome and comparison with clonidine have been investigated in morphine-dependent rats. Adult male Wistar rats were subjects. The frequencies of withdrawal behavioral signs (rearing, teeth chattering and jumping) induced by naloxone challenge were demonstrated in morphine dependent rats receiving Hypericum perforatum extract (HPE), saline or clonidine. The withdrawal behavioral manifestations in rats were inhibited significantly by chronic co-administration of Hypericum perforatum extract or clonidine with morphine. This study showed that clonidine was more effective than HPE at a dose of 0.4 mL/200 g and there was no significant statistical difference between the mean frequency of withdrawal signs of HPE at a dose of 0.8 mL/200 g compared with clonidine (0.2 mg/kg i.p.) but at a dose of 1.2 mL/200 g of HPE was significantly stronger than clonidine in attenuation of the morphine withdrawal syndrome.The findings suggest that HPE is capable of reducing the symptoms of opiate withdrawal and its effectiveness may be equivalent to clonidine in reducing the opiate withdrawal syndrome and may have human therapeutic potential.

Antiproliferative activity: Extract versus isolated active constituent

Recently, there have been extensive efforts to evaluate the chemopreventive role of substances present in natural products. We compared the antiproliferative potency (measured by WST-1 assay) of four plant extracts from the gum resin of Boswellia serrata Roxb., Hypericum perforatum L., Cimicifuga racemosa L.and Salix sp. to their biologically active compounds boswellic acid (AKBA), hypericin (HY), hyperforin (HP), triterpene glycosides (TTG), cinnamic acid esters (CAE) and salicin (SAL) using different cancer cells. Substances were compared by their GI50 values. In three leukaemia cell lines (K562, U937 and MOLT-4) the effect of the crude extract of B. serrata was 2.3–3.3 times more potent than AKBA [1].The antiproliferative effect of H. perforatum extract depends on light activation of HY. However, in the dark, the effect of H. perforatum extract on K562 and U937 cells was found 10-times more potent than HY, but 2-times less potent than HP [2]. Furthermore, HY and HP acted synergistically on cell growth inhibition in the dark [3]. The effect of two main classes of compounds, TTG and CAE on breast ER+ MCF-7 and ER- MDA MB231 cancer cells was 2.2–3 times and 4–6 times less potent in comparison to their parent isopropanolic C. racemosa extract [4]. Effect of willow bark extract, its fraction of salicylic alcohol derivates F1 [5] and SAL was investigated on the cell growth of COX-2-proficient HT-29 and COX-2-deficient HCT 116 colon cancer cells. There were differences of about two decades of logarithmic scale for favour of extract in comparison to the single compound SAL and the parent extract was 3-times more potent than the isolated fraction F1. Natural products as a multiple compounds mixtures possess the potential to attack cancer cells more effectively than their single active constituents.

Influence of Hypericum perforatum Extract on Piglet Infected with Porcine Respiratory and Reproductive Syndrome Virus

To study the influence of Hypericum perforatum extract (HPE) on piglets infected with porcine respiratory and reproductive syndrome virus (PRRSV), enzyme-labeled immunosorbent assay (ELISA) and cytopathic effect (CPE) were used to determine in vitro whether HPE could induce swine pulmonary alveolar macrophages (PAMs) to secrete IFN-g, and whether PRRSV titers in PAMs were affected by the levels of HPE-induced IFN-g. HPE (200 mg kg −1) was administrated by oral gavage to piglets infected with the PRRSV in vivo to observe whether HPE affected the viremia, lung viral titers, and weight gain of piglets infected with PRRSV. The results showed that HPE was capable of inducing PAMs to produce IFN-g in a dose dependent manner and HPE pretreatment was capable of significantly reducing PRRSV viral titers in PAMs ( P < 0.01). Administration of HPE to the PRRSV-infected animals significantly ( P < 0.05) reduced viremia over time as compared with the PRRSV-infected animals. But there was not significant decrease in lung viral titers at day 21 post-infection between the HPE-treated animals and the PRRSV-infected control piglets. There were no significant differences in weight gain over time among the HPE-treatment animals, the normal control, and the HPE control animals. The PRRSV-infected animals caused significant ( P < 0.01) growth retardation as compared with the HPE controls and the normal piglets. It suggested that HPE might be an effective novel therapeutic approach to diminish the PRRSV-induced disease in swine.

Effects of Hypericum perforatum (St. John's wort) on hot flashes and quality of life in perimenopausal women

The aim of this pilot double-blind, randomized clinical trial, which initially targeted breast cancer survivors, was to obtain preliminary evidence of the effect of Hypericum perforatum extract (St. John's wort extract) compared with placebo on symptoms and quality of life of symptomatic perimenopausal women. We also assessed practical difficulties in recruiting women to such a trial. Symptomatic perimenopausal women aged 40 to 65 years who experience hot flashes (three or more per day, Heart and Estrogen/Progestin Replacement Study scale) were randomly assigned to receive ethanolic St. John's wort extract (900 mg TID) or placebo. The women were asked to keep a daily diary during the week before randomization and during the week before the 3-month follow-up (primary outcome) to record hot flash frequency and intensity. A hot flash score (frequency x severity) was calculated. The Menopause-Specific Quality of Life questionnaire was used to assess menopause-specific quality of life. Forty-seven women were randomized. After 12 weeks of treatment, a nonsignificant difference favoring the St. John's wort group was observed in the daily hot flash frequency (St. John's wort, -2.3 +/- 3.6; placebo, -1.0 +/- 2.2; P = 0.11) and the hot flash score (-3.8 +/- 8.3 and -1.8 +/- 6.5, respectively; P = 0.10). After 3 months of treatment, compared with the placebo group, women in the St. John's wort group reported significantly better menopause-specific quality of life (P = 0.01) and significantly fewer sleep problems (P = 0.05). Hypericum perforatum may improve quality of life in ways that are important to symptomatic perimenopausal women, but these results need to be confirmed by a larger clinical trial.

Study of active naphtodianthrone St John's Wort compounds by electrospray ionization Fourier transform ion cyclotron resonance and multi‐stage mass spectrometry in sustained off‐resonance irradiation collision‐induced dissociation and infrared multiphoton dissociation modes

Five well-known active naphtodianthrone constituents of Hypericum perforatum (St John's Wort) extracts have been investigated by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) and ESI-FTICRMSn. The studied compounds were hypericin, pseudohypericin, protohypericin, protopseudohypericin (biosynthetic precursors of the two former compounds, respectively) and isopseudohypericin (alkaline degradation product of pseudohypericin). Dissociation mass spectrometry measurements performed on the [M-H]- ion presented a variable efficiency as a function of the used activation mode. Sustained off-resonance irradiation collision-induced dissociation (SORI-CID) only led to a restricted number of fragment ions. In contrast, IRMPD ensured the detection of numerous product ions. Ions detected in ESI-FTICRMS and ESI-FTICRMSn experiments were measured with a very high mass accuracy (typically mass error is lower than 0.5 mDa at m/z close to 500) that allowed unambiguous formulae to be assigned to each signal observed in a mass spectrum. In spite of similar structures, specific fragmentation patterns were observed for the different compounds investigated. This study may be useful in the future to characterize in natural extracts these compounds (or derivatives of these compounds) by liquid chromatography/tandem mass spectrometry (LC/MS/MS) experiments by considering the MS/MS transitions highlighted in this paper.