Caspase-8 acts as a key upstream executor of mitochondria during justicidin A-induced apoptosis in human hepatoma cells

Evaluation of potency and metabolic stability of diphyllin-derived Vacuolar-ATPase inhibitors

Diphyllin is a naturally occurring lignan comprised of an aryl naphthalene lactone scaffold that demonstrates beneficial biological activities in disease models of cancer, obesity, and viral infection. A target of diphyllin and naturally occurring derivatives is the vacuolar ATPase (V-ATPase) complex. Although diphyllin-related natural products are active with in vitro models for viral entry, the potencies and unknown pharmacokinetic properties limit well-designed in vivo evaluations. Previous studies demonstrated that diphyllin derivatives have the utility of blocking the Ebola virus cell entry pathway. However, diphyllin shows limited potency and poor oral bioavailability in mice. An avenue to improve the potency was used in a new library of synthetic derivatives of diphyllin. Diphyllin derivatives exploiting ether linkages at the 4-position with one-to-three carbon spacers to an oxygen or nitrogen atom provided compounds with EC50 values ranging from 7 to 600 nM potency and selectivity up to >500 against Ebola virus in infection assays. These relative potencies are reflected in the Ebola virus infection of primary macrophages, a cell type involved in early pathogenesis. A target engagement study reveals that reducing the ATPV0a2 protein expression enhanced the potency of diphyllin derivatives to block EBOV entry, consistent with effects on the endosomal V-ATPase function. Despite the substantial enhancement of antiviral potencies, limitations were identified, including rapid clearance predicted by in vitro microsome stability assays. However, compounds with similar or improved half-lives relative to diphyllin demonstrated improved pharmacokinetic profiles in vivo. Importantly, these derivatives displayed suitable plasma levels using oral administration, establishing the feasibility of in vivo antiviral testing.

ERS Mediated by GRP-78/PERK/CHOP Signaling Is Involved in Fluoride-Induced Ameloblast Apoptosis

Fluoride can be widely ingested from the environment, and its excessive intake could result in adverse effects. Dental fluorosis is an early sign of fluoride toxicity which can cause esthetic and functional problems. Though apoptosis in ameloblasts is one of the potential mechanisms, the specific signal cascade is in-conclusive. High-throughput sequencing and molecular biological techniques were used in this study to explore the underlying pathogenesis of dental fluorosis, for its prevention and treatment. A fluorosis cell model was established. Viability and apoptosis rate of mouse ameloblast-derived cell line (LS8 cells) was measured using cell counting kit-8 (CCK-8) assay and flow cytometry analysis. Cells were harvested with or without 2-mM sodium fluoride (NaF) stimulation for high-throughput sequencing. Based on the sequencing data, subcellular structures, endoplasmic reticulum stress (ERS), and apoptosis related biomarkers were verified using transmission electron microscopy, quantitative real-time polymerase chain reaction, and Western blotting techniques. Expression of ERS markers, apoptosis related proteins, and enamel formation enzymes were detected using Western blotting after addition of 4-phenylbutyrate (4-PBA). NaF-inhibited LS8 cells displayed time- and dose- dependent viability. Additionally, apoptosis and morphological changes were observed. RNA-sequencing data showed that protein processing in endoplasmic reticulum was obviously affected. ERS and apoptosis were induced by excessive NaF. Downregulation of kallikrein-related peptidase 4 (KLK4) was also observed. Inhibition of ERS by 4-PBA rescued the apoptotic and functional protein changes in cells. Excessive fluoride induces apoptosis by activating ERS, which is mediated by GRP-78/PERK/CHOP signaling. Key proteinase is present in maturation-stage enamel; KLK4 was also affected by fluoride, but rescued by 4-PBA. This study presents a possibility for therapeutic strategies for dental fluorosis, while further exploration is required.

A Strategy for Preparative Separation of 10 Lignans from Justicia procumbens L. by High-Speed Counter-Current Chromatography

Ten compounds, including three lignan glycosides and seven lignans, were purified from Justicia procumbens L. in 8 h using an efficient strategy based on high-speed counter-current chromatography (HSCCC). The two-phase solvent system composed of petroleum–ethyl acetate–methanol–H₂O (1:0.7:1:0.7, v/v) was firstly employed to separate the crude extract (320 mg), from which 19.3 mg of justicidin B (f), 10.8 mg of justicidin A (g), 13.9 mg of 6′-hydroxyjusticidin C (h), 7.7 mg of justicidin E (i), 6.3 mg of lignan J₁ (j) were obtained with 91.3 mg of enriched mixture of compounds a–e. The enriched mixture (91.3 mg) was further separated using the solvent system consisting of petroleum–ethyl acetate–methanol–H₂O (3:3.8:3:3.8, v/v), yielding 12.1 mg of procumbenoside E (a); 7.6 mg of diphyllin-1-O-β-d-apiofuranoside (b); 7.4 mg of diphyllin (c); 8.3 mg of 6′-hydroxy justicidin B (d); and 7.9 mg of diphyllin acetyl apioside (e). The purities of the 10 components were all above 94%, and their structures were identified by NMR and ESI-MS spectra. The results demonstrated that the strategy based on HSCCC for the separation of lignans and their glycosides was efficient and rapid.

Differential modulation of Bax/Bcl-2 ratio and onset of caspase-3/7 activation induced by derivatives of Justicidin B in human melanoma cells A375

Diphyllin and its derivatives are well known cytotoxic natural products structurally related to the anti-cancer drug podophyllotoxin. We here study their structure-activity relationship upon human melanoma cells for first time. To this end, human melanoma A375 cells were incubated with Justicidin B and its 4-methoxylated or 4-glycosylated derivatives to evaluate their selective cytotoxicity and study their effects on cell cycle distribution, caspase activation, apoptosis induction using Annexin V-FITC/PI staining, cell morphology and western blot analysis. Diphyllin methyl ether (GI₅₀ = 3.66 μM) and Justicidin B (GI₅₀ = 1.70 μM) caused an elevation of both early and late apoptosis populations whereas Diphyllin apioside (GI₅₀ = 0.84 μM) and its acetate (GI₅₀= 0.39 μM) enhanced late apoptosis population only (Annexin V-positive/PI-positive). All induced cell cycle arrest at S phase and classic morphological indicators of apoptosis (blebbing, apoptotic bodies, and nuclear fragmentation) accompanied with an elevation of cells with low DNA content (sub-G1). All compounds increased the Bax/Bcl-2 ratio by enhancing Bax expression which evidences the involvement of the mitochondria (intrinsic pathway) in the apoptotic process. These caspase-3/7 results evidence that 4-methoxylation or 4-O-glycosylation of Justicidin B -a caspase independent mitochondrial apoptosis-inducer- triggers caspase-3/7 activation at different times (24h vs. 48h, respectively). Interestingly, the methoxylation causes attenuation of Bcl-2 protein expression contrarily to Diphyllin methyl ether or the O-glycosylated derivatives. Finally, the compounds exhibited significantly less toxicity when tested in adult human dermal fibroblasts and their GI₅₀ in melanoma Sk-Mel-5 cells was not influenced by MDR1/Pgp inhibitors. This study may inform the synthesis of future Diphyllin derivatives with different apoptosis mechanism of action towards human melanoma cells.

Determination and pharmacokinetics of chinensinaphthol methyl ether in rat urine by a sensitive and specific UFLC-ESI-MS/MS method

A rapid, stable, and sensitive method based on ultra-fast liquid chromatography combined with electrospray ionization tandem mass spectrometry (UFLC-ESI-MS/MS) was established and optimized for quantification and pharmacokinetics analysis of chinensinaphthol methyl ether (CME) in rat urine. Samples were prepared by liquid phase extraction with ethyl acetate, and chromatographic separation was performed on an ACQUITY UPLC(®) BEH Phenyl column (2.1×50mm, 1.7μm). For gradient elution, we used a mobile phase consisting of water containing 0.1% formic acid and 5mmol/L ammonium formate and methanol with 0.1% formic acid. The quantification was executed under multiple reaction monitoring (MRM) in positive mode. The precursor/product transition (m/z) in the positive ion mode was [M+H](+)m/z=395.1→346.1. This method was validated by evaluating specificity, linearity, matrix effects, recovery, accuracy, precision, and stability, which were all shown to be reasonable and reliable. The lower limit of quantification (LOQ) was 0.5ng/mL, and the linear range was 0.5-100ng/mL. The method was successfully applied to quantify and analyze the pharmacokinetics of CME in rat urine. After oral administration of a single dose of CME (5.0mg/kg), the accumulated amount of CME excreted in urine was 162.3±54.1ng, and the terminal elimination half-life was 53.4±5.3h, indicating low CME excretion in urine and significant CME metabolism in vivo.

Antiangiogenesis as the novel mechanism for justicidin A in the anticancer effect on human bladder cancer

Justicidin A (JA) is one of the methanol extracts of Justicia procumbens and was reported to induce apoptosis and inhibit the proliferation of human colon cancer cells. Using bladder cancer as a paradigm, this study was designed to identify the novel molecular basis underlying the antiangiogenic activities of JA and its potential in cancer therapy. Human bladder cancer cell lines (TSGH8301 and RT4) and immortalized uroepithelial cell lines (E6 and E7) were chosen to investigate the efficacy of JA in cell proliferation, apoptosis, and angiogenesis in vitro. The biological effects of JA treatment in vivo were examined using a xenograft tumor model in SCID mice. JA showed a dose-dependent and time-dependent inhibition of cell proliferation on TSGH8301 cancer cells, with IC50 values determined to be 0.44 μmol/l. Of interest, TSGH8301 cancer cells were more sensitive to JA than E7 immortalized uroepithelial cells, especially at lower concentrations. We further showed that JA inhibited the autocrine production of angiogenic factors and matrix-degrading enzymes in vitro and microvessel density in SCID mice in vivo (P< 0.01). Both differential cytotoxicity and angiogenesis inhibition of JA were confirmed by SCID mice experiments. Together, JA showed antiangiogenesis in vitro and in vivo through pleiotropic positive and negative regulators of angiogenesis molecules. The current investigation supports the potential of JA as an alternative chemoprevention agent for human bladder cancer.

Justicidin A-induced autophagy flux enhances apoptosis of human colorectal cancer cells via class III PI3K and Atg5 pathway

Our previous reports showed that justicidin A (JA), a novel and pure arylnaphthalide lignan isolated from Justicia procumbens, induces apoptosis of human colorectal cancer cells and hepatocellular carcinoma cells, leading to the suppression of both tumor cell growth in NOD-SCID mice. Here, we reveal that JA induces autophagy in human colorectal cancer HT-29 cells by conversion of autophagic marker LC3-I to LC3-II. Furthermore, LC3 puncta and autophagic vesicle formation, and SQSTM1/p62 suppression were observed. Administration of autophagy inhibitor (bafilomycin A1 and chloroquine) and transfection of a tandem fluorescent-tagged LC3 (mRFP-GFP) reporter plasmid (ptfLC3) demonstrated that JA induces autophagy flux in HT-29 cells. Expression of LC3, SQSTM1, Beclin 1, and nuclear DNA double-strand breaks (representing apoptosis) were also detected in the tumor tissue of HT-29 cells transplanted into NOD-SCID mice orally administrated with JA. In addition, the expression of autophagy signaling pathway-related molecules p-PDK1, p-mTOR, p-p70S6k/p-RPS6KB2 was decreased, whereas that of class III PI3K, Beclin 1, Atg5-Atg12, and mitochondrial BNIP3 was increased in response to JA. Pre-treatment of the cells with class III PI3K inhibitor 3-methyladenine or Atg5 shRNA attenuated JA-induced LC3-II expression and LC3 puncta formation, indicating the involvement of class III PI3K and Atg5. A novel mechanism was demonstrated in the anticancer compound JA; pre-treatment with 3-methyladenine or Atg5 shRNA blocked JA-induced suppression in cell growth and colony formation, respectively, via inhibition of apoptosis. In contrast, administration of apoptosis inhibitor Z-VAD did not affect JA-induced autophagy. Our data suggest the chemotherapeutic potential of JA for treatment of human colorectal cancer.

Preparative isolation and purification of lignans from Justicia procumbens using high-speed counter-current chromatography in stepwise elution mode

Lignans, which are recognized as main constituents in Justicia procumbens, have attracted considerable attention due to their pharmacological activities, including antitumor, anti-hepatitic, cytotoxic, anti-microbial, and anti-virus properties. Preparative high-speed counter-current chromatography (HSCCC) was successfully applied to the isolation and purification of four lignans (justicidin B (1), justicidin A (2), 6'-hydroxyjusticidin C (3) and lignan J1 (4)) from J. procumbens using stepwise elution with a pair of two-phase solvent systems composed of n-hexane-ethyl acetate-methanol-water at (1.3:1:1.3:1, v/v) and (2.5:1:2.5:1, v/v). The preparative HSCCC separation was performed on 300 mg of crude sample yielding compounds 1 (19.7 mg), 2 (9.86 mg), 3 (11.26 mg), and 4 (2.54 mg) in a one-step separation, with purities over 95% as determined by HPLC. The structures of these compounds were identified by MS, 1H-NMR and 13C-NMR. This is the first report on the application of HSCCC to the efficient separation of lignans from J. procumbens.

The novel heterocyclic trioxirane [(1,3,5-tris oxiran-2-yl)methyl)-1,3,5-triazinane-2,4,6-trione (TATT)] exhibits a better anticancer effect than platinum-based chemotherapy by induction of apoptosis and curcumin further enhances its chemosensitivity

The heterocyclic trioxirane compound [1,3,5-tris((oxiran-2-yl)methyl)-1,3,5-triazinane-2,4,6-trione (TATT)] is a synthetic compound which has been used as an experimental anticancer agent in human clinical trials. Curcumin, an active natural compound in turmeric and curry, is an ingredient commonly used in the traditional diet of many Asian countries. In the present study, we observed that TATT exhibited a better anticancer effect on chemoresistant human colorectal cancer HT-29 cells and displayed less cytotoxicity on normal human umbilical vein endothelial cells, compared with FDA-approved anticancer drugs (cisplatin, carboplatin, or oxaliplatin) using MTT assay. TATT also induced a stronger apoptotic effect than that seen with the three studied anticancer drugs, as characterized by externalization of phosphatidylserine using flow cytometry. Administration of caspase 8-specific inhibitor (z-IETD-fmk) and mitochondrial permeability transition pore inhibitor (cyclosporin A) demonstrated that TATT-induced apoptosis proceeded via both extrinsic and intrinsic signaling pathways. It is noteworthy that coadministration of curcumin further significantly increased TATT-induced cytotoxicity, externalization of phosphatidylserine (representing early apoptosis), and the percentages of cells at the sub-G1 phase (representing late apoptosis), producing an additivity and/or synergistic effect, and vice versa. Suppression of nuclear NF-κB was involved in curcumin-enhanced chemosensitivity of TATT. Overall, our data indicate that TATT exerts a chemotherapeutic effect on colorectal cancer cells and coadministration of curcumin enhances the treatment effect of TATT.

Apoptotic mechanisms of the biotechnologically produced arylnaphtalene lignan justicidin B in the acute myeloid leukemia-derived cell line HL-60

BACKGROUND

The present study aimed at optimization of the biotechnological production of the lignan justicidin B by genetically transformed cultures of Linum leonii and the pharmacological evaluation of the pro-apoptotic effects of the compound in HL-60 cells.

METHODS

A rapidly growing selected root line of L. leonii was grown in 2-L bioreactor for period of 40 days and the protocols for obtaining of the compound have been optimized. The pharmacological study included evaluation of the cytotoxicity of the compound in HL-60 cells (MTT-assay), its apoptogenic effects and its effects on caspase 3,8 and 9 activation.

RESULTS

After 40 days of sterile run scale up of hairy root culture in bioreactor, 27.2g/L dry weight of root biomass was harvested from the bioreactor culture vessel, recording about nine times increase over initial inoculum (3.0g), with 1.55%±0.07 Justicidin B, greater than yields from 300ml flasks. Our findings are the first work toward the scale up of L. leonii hairy roots-based biotechnological production of Justicidin B, employing bioreactors for high biomass production to meet the industrial requirement. The results from the pharmacological evaluation have shown that the tested arylnaphtalene lignan is a potent cytotoxic and proapoptotic agent against HL-60. The induction of apoptosis proceeds via activation of the intrinsic mitochondrial cell-death signaling pathways.

CONCLUSION

The potent activity at low micromolar concentration and the feasibility of biotechnological production of justicidin B implies that there is enormous scope in its further evaluation as possible antineoplastic drug candidate.

Evaluation and structure-activity relationship analysis of a new series of arylnaphthalene lignans as potential anti-tumor agents

Arylnaphthalene lignan lactones have attracted considerable interest because of their anti-tumor and anti-hyperlipidimic activities. However, to our knowledge, few studies have explored the effects of these compounds on human leukemia cell lines. In this study, five arylnaphthalene lignans including 6′-hydroxy justicidin A (HJA), 6′-hydroxy justicidin B (HJB), justicidin B (JB), chinensinaphthol methyl ether (CME) and Taiwanin E methyl ether (TEME) were isolated from Justicia procumbens and their effects on the proliferation and apoptosis of the human leukemia K562 cell line were investigated then used to assess structure-activity relationships. To achieve these aims, cytotoxicity was assayed using the MTT assay, while intracellular SOD activity was detected using the SOD Activity Assay kit. Apoptosis was measured by both the using a cycle TEST PLUS DNA reagent kit as well as the FITC Annexin V apoptosis detection kit in combination with flow cytometry. Activation of caspase-mediated apoptosis was evaluated using a FITC active Caspase-3 apoptosis kit and flow cytometry. The results indicated that HJB, HJA and JB significantly inhibited the growth of K562 cells by decreasing both proliferation and SOD activity and inducing apoptosis. The sequence of anti-proliferative activity induced by the five tested arylnaphthalenes by decreasing strength was HJB > HJA > JB > CME > TEME. HJB, HJA and JB also decreased SOD activity and induced apoptosis in a dose-dependent manner. Activation of caspase-3 further indicated that HJB, HJA and JB induced caspase-dependent intrinsic and/or extrinsic apoptosis pathways. Together, these assays suggest that arylnaphthalene lignans derived from Justicia procumbens induce apoptosis to varying degrees, through a caspase-dependent pathway in human leukemia K562 cells. Furthermore, analysis of structure-activity relationships suggest that hydroxyl substitution at C-1 and C-6′ significantly increased the antiproliferative activity of arylnaphthalene lignans while a methoxyl at C-1 significantly decreased the effect.

Targeting caspases in cancer therapeutics

The identification of the fundamental role of apoptosis in the growth balance and normal homeostasis against cell proliferation led to the recognition of its loss contributing to tumorigenesis. The mechanistic significance of reinstating apoptosis signaling towards selective targeting of malignant cells heavily exploits the caspase family of death-inducing molecules as a powerful therapeutic platform for the development of potent anticancer strategies. Some apoptosis inhibitors induce caspase expression and activity in preclinical models and clinical trials by targeting both the intrinsic and extrinsic apoptotic pathways and restoring the apoptotic capacity in human tumors. Furthermore, up-regulation of caspases emerges as a sensitizing mechanism for tumors exhibiting therapeutic resistance to radiation and adjuvant chemotherapy. This review provides a comprehensive discussion of the functional involvement of caspases in apoptosis control and the current understanding of reactivating caspase-mediated apoptosis signaling towards effective therapeutic modalities in cancer treatment.

Simultaneous determination of seven lignans in Justicia procumbens by high performance liquid chromatography-photodiode array detection using relative response factors

A simple and sensitive HPLC coupled with photodiode array (HPLC-PDA) method was developed for simultaneous determination of seven lignans in Justicia procumbens using relative response factors (RRFs). The chromatographic separation was performed on a Shiseido Capcell Pak C(18) column (250 × 4.6 mm id, 5 μm), a gradient elution of acetonitrile/water, and a photodiode array detector. The column temperature was maintained at 35°C and the detection wavelength was set at 256 nm. Chinensinaphthol methyl ether was selected as the reference compound for calculating the relative response factors of the lignans. It has shown that the RRFs for lignans are quite similar at 256 nm of detection under different analytical conditions (different columns and HPLC instruments). Using RRFs, not every lignan is needed as a reference standard, making the method ideal for rapid, routine analysis, especially for those laboratories where lignans standards are not readily available. An economic and practicable HPLC method using RRFs was established for the determination of seven lignans in J. procumbens. This method not only can determine multiple indexes in traditional Chinese medicines (TCMs) simultaneously, but also resolve the problem of lacking of chemical standards. It will be a good quality evaluation method and pattern for TCMs.

JR6, a new compound isolated from Justicia procumbens, induces apoptosis in human bladder cancer EJ cells through caspase-dependent pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Numerous efforts have been conducted in searching for effective agents against cancer, in particular from herbal medicines. Justicia procumbens is a traditional herbal remedy which was produced in the south-western and southern provinces of China and Taiwan province used to treat fever, pain, and cancer. Here, we identified a new compound 6'-hydroxy justicidin A (JR6) from Justicia procumbens, which showed obvious anti-cancer effects.

MATERIALS AND METHODS

The cytotoxicity activity was assayed using MTT and SRB. Intracellular ROS visualization and quantification were acquired by using a laser scanning confocal microscopy. Apoptosis was measured using a propidium iodide (PI) apoptosis detection kit by flow cytometry. Activation of caspases (caspase-3, caspase-8, and caspase-9) was evaluated respectively using GloMax luminescence detector and Caspase-Glo 3,8,9 assay kits. Loss of mitochondrial membrane potential was observed by microscopy using JC-1 dye. Quantitative real-time PCR analysis was employed to detect the expression of protein associated with cell death.

RESULTS

JR6 remarkably inhibited growth in human bladder cancer EJ cells by decreasing cell proliferation, reduced the SOD activity, increased the content of reactive oxygen species (ROS), and induced apoptosis. Activation of caspase-8, caspase-9, and the subsequent activation of caspase-3 indicated that JR6 may be inducing intrinsic and extrinsic apoptosis pathways. Caspase-3, caspase-8, and caspase-9 inhibition rendered this extract ineffective, thus JR6-induced apoptosis is caspase-dependent. JR6 also disrupted the mitochondrial membrane potential (Δψm) and unregulated the Bax and p53 expressions in EJ cells.

CONCLUSION

These observations suggest that JR6 induce apoptosis through caspase-dependent pathway in human bladder cancer EJ cells, emphasizing the importance of this traditional medicine and thus presents a potential novel alternative to bladder cancer therapy.

The caspase pathway of linoelaidic acid (9t, 12t-c18:2)-induced apoptosis in human umbilical vein endothelial cells

Trans fatty acids (TFA) are reported to contribute to inflammation and coronary heart disease. The study aim was to investigate the proapoptotic effects of two double bond TFA (TDTFA) on human umbilical vein endothelial cells (HUVEC). The HUVEC were grown in media supplied with linoelaidic acid (9t,12t-C18:2) at 50, 100, 200, 400 μmol/l for 24 or 48 h to examine the effects of TDTFA on the viability and apoptosis of these cells. Flow cytometry analysis and confocal scanning were used to measure apoptosis, cell binding of Annexin V and propidium iodide uptake. Colorimetric assay and RT-PCR were used to analyze enzyme activities and mRNA expression of caspase-3, -8 and -9 in HUVEC. Results showed that 9t,12t-C18:2 inhibited the viability of HUVEC in a dose-dependent and time-dependent manner. The percentages of 9t,12t-C18:2 induced apoptotic and necrotic cells significantly increased compared with that of the control. The activities and mRNA expression of caspase-8, -9 and -3 were significantly increased in 9t,12t-C18:2 treated cells compared to that of the control. Addition of specific inhibitors of caspase-8 (z-IETD-fmk) and caspase-9 (z-LEHD-fmk) to HUVEC was found to completely inhibit 9t,12t-C18:2-induced activation of caspase-3, and z-IETD-fmk inhibited the activation of caspase-9. Meanwhile, it was found that mRNA expression of Bid, Smac/DIABLO and the release of mitochondrial cytochrome c were significantly elevated by 9t,12t-C18:2 treatment. These results suggest that 9t,12t-C18:2 may induce apoptosis of HUVEC through activating caspase-8, -9 and -3. Both the death receptor pathway and the mitochondrial pathway may be involved in the apoptosis induced by 9t,12t-C18:2.

Chromatographic fingerprint analysis and simultaneous determination of eight lignans in Justicia procumbens and its compound preparation by HPLC-DAD

HPLC fingerprints were developed for the quality evaluation of Justicia procumbens and its compound preparation, Jian-er syrup, together with the simultaneous quantification of eight arylnaphthalide lignans (6'-hydroxy justicidin B, 6'-hydroxy justicidin A, 6'-hydroxy justicidin C, justicidin B, chinensinaphthol methyl ether, justicidin C, taiwanin C, and neojusticin A). Samples were separated with a Shiseido Capcell Pak C(18) reversed-phase column (250×4.6 mm id, 5 μm) using acetonitrile and water as the mobile phase. The column temperature was maintained at 35°C and the wavelength of detector was set at 256 nm. For fingerprint analysis, 17 peaks were selected as the characteristic peaks for the evaluation of the similarities among different J. procumbens samples collected in different places. The structures of lignans were confirmed by diagnostic fragments in the positive ESI-MS(n) . The new method was successfully applied for the chromatographic fingerprint analysis and simultaneous determination of eight lignans in its compound preparation, Jian-er syrup. All the results indicated that HPLC fingerprint assay in combination with multi-marker determination afforded a useful method for the quality control of J. procumbens and its compound preparation, Jian-er syrup.

Formosanin C-induced apoptosis requires activation of caspase-2 and change of mitochondrial membrane potential

Formosanin C is a pure compound isolated from Paris formosana Hayata (Liliaceae). The antitumor efficacy of formosanin C has been observed in cultured cells and animal systems. However, the molecular mechanisms of formosanin C remain unknown. The results of the present study indicate that formosanin C induced apoptosis of HT-29 cells characterized by exposure of phosphatidylserine, accumulation of cells at the sub-G(1) phase, fragmentation of DNA, and change of nuclear morphology in a time- and dose-related manner. The apoptotic signaling cascades may proceed via proteolytic activation of caspase-2, change of mitochondrial membrane potential (Deltapsi(m)), release of cytochrome c and second mitochondria-derived activator of caspase/direct IAP binding protein with low pI (Smac/DIABLO), activation of caspase-9 and -3, and cleavage of poly(ADP-ribose) polymerase (PARP). Increase in apoptosis-inducing factor and endonuclease G expressions in nuclei, and increase in Bax and Bak expressions and decrease in Bcl-X(L) expression on mitochondria were also observed in formosanin C-treated HT-29 cells. Attenuation of formosanin C-induced change of Deltapsi(m) by caspase-2 inhibitor (Z-VDVAC) implies that caspase-2 acts upstream of the mitochondria. Blockage of formosanin C-induced apoptotic process by using either permeability transition pore inhibitor (cyclosporine A) or caspase-9 inhibitor (Z-LEHD) demonstrates the necessity of mitochondria and caspase-9 in formosanin C-induced apoptosis of HT-29 cells. Taken together, the apoptotic mechanism of formosanin C in human colorectal cancer HT-29 cells involves activation of caspase-2 and the dysfunction of mitochondria.

Complete assignments of 1H and 13C NMR data for three new arylnaphthalene lignan from Justicia procumbens

Three new arylnaphthalene lignans, named neojusticin C (1), procumbenoside C (2) and procumbenoside D (3), have been isolated from the whole plant of Justicia procumbens, together with three known ones, justicidinoside B (4), justicidinoside C (5), and diphyllin-1-O-beta-D-apiofuranoside (6). The complete assignments of 1H and 13C NMR data for three new lignans were first obtained by means of 2D NMR techniques, including HSQC and HMBC.

DNA strand-scission by phloroglucinols and lignans from heartwood of Garcinia subelliptica Merr. and Justicia plants

Five 2,4,6-prenylated phloroglucinols, garcinielliptones HA (1), HB (2), HC (3), HD (4) and HE (5), were isolated from the heartwood of Garcinia subelliptica Merr. Their structures, including relative configurations, were elucidated by means of spectroscopic data analysis. The ability of phloroglucinols, 1-5 and lignans, tuberculatin (8), justicidin A (9), procumbenoside A (10) and ciliatosides A (11) and B (12), isolated from Justicia ciliata and Justicia procumbens, to induce DNA-cleavage activity was examined using pBR322, a supercoiled, covalently closed circular DNA, and it was analyzed by agarose gel electrophoresis. In the presence of Cu (II), compounds 3, 8, 10 and 11 caused significant breakage of supercoiled plasmid pBR322. The products were relaxed circles with no detectable linear forms. In the Cu(II)-mediated DNA damage of 3 and selective compound 8, Cu(I) was shown not to be an essential intermediate by using the Cu(I)-specific sequestering reagent neocuproine.

Laxanol, a new 2,5-Diaryl-3,4-Dihydroxymethyltetrahydrofuran Type Lignan from Justicia Laxa

The unsymmetrical 2,5-diaryl-tetrahydrofuran type lignan, 2-(3′-methoxy-4′-hydroxyphenyl)-3,4-dihydroxymethyl-5-(3″-methoxy-5″-hydroxyphenyl)-tetrahydrofuran, laxanol (1), was obtained from Justicia laxa via high-throughput natural product chemistry methods as a mass-limited sample and its structure was elucidated by capillary scale NMR and HR-/LR-ESIMS analyses.