ß-Carboline alkaloids from the roots of Peganum harmala L.

This study reports the isolation of four new ß-carboline alkaloids (1-4) and six previously identified alkaloids (5-10) from the roots of Peganum harmala L. Among these compounds, 1 and 2 were characterized as rare ß-carboline-quinazoline dimers exhibiting axial chirality. Compound 3 possessed a unique 6/5/6/7 tetracyclic ring system with an azepine ring, and compound 4 was a novel annomontine ß-carboline. The structures of these compounds were elucidated by spectroscopic data and quantum mechanical calculations. The biosynthetic pathways of 1-3 were proposed. Additionally, the cytotoxicity of some isolates against four cancer cell lines (HL-60, A549, MDA-MB-231, and DU145) was evaluated. Notably, compound 4 exhibited significant cytotoxicity against HL-60, A549, and DU145 cells with IC50 values of 12.39, 12.80, and 30.65 µmol·L-1, respectively. Furthermore, compound 2 demonstrated selective cytotoxicity against HL-60 cells with an IC50 value of 17.32 µmol·L-1.

Green synthesis and bactericidal activities of isotropic and anisotropic spherical gold nanoparticles produced using Peganum harmala L leaf and seed extracts.

Shape, size, and homogeneity affect the biological activity of gold nanoparticles (AuNPs) in nanomedicine and catalytic applications. Here we biosynthesized monodispersed isotropic and polydispersed anisotropic spherical AuNPs from leaf and seed extract broths of the medicinal plant Peganum harmala L. (Ph. L). Synthesized AuNPs were characterized by ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IRS), field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), and transmission electron microscopy (TEM). The antimicrobial activity of AuNPs against Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) human pathogens was also assessed. Leaf- and seed-derived AuNPs had characteristic localized surface plasmon resonances of 530 and 578 nm, respectively. TEM, FE-SEM, EDX, and XRD revealed the formation of elemental face-centered cubic spherical monodispersed isotropic AuNPs of average size 43.44 nm and polydispersed anisotropic AuNPs of average size 52.04 nm from leaf and seed extract broths, respectively. FT-IR revealed polyphenols and alcohols as responsible for AuNP capping, reduction, and protection. Anisotropic AuNPs showed no antibacterial activity, whereas isotropic AuNPs showed good inhibition of both E. coli and S. aureus. This represents a simple and ecofriendly protocol for the green synthesis of monodispersed isotropic spherical AuNPs, which may have value in a variety of applications.

Suppression of Non-Small Cell Lung Cancer Growth and Metastasis by a Novel Small Molecular Activator of RECK.

BACKGROUND/AIMS: Reversion-inducing cysteine-rich protein with kazal motifs (RECK) is a novel tumor suppressor gene that is critical for regulating tumor cell invasion and metastasis. The expression of RECK is dramatically down-regulated in human cancers. Harmine, a tricyclic compound from Peganum harmala, has been shown to have potential anti-cancer activity. METHODS: Cell proliferation assay (CCK-8 cell viability assay), cell cycle analysis (detection by flow cytometry), apoptosis staining assay (TUNEL staining), cell migration assay and invasion assay (transwell assay) were carried out to investigate the Harmine's efficacy on non-small cell lung cancer (NSCLC) cells in vitro. A549-luciferase cell orthotropic transplantation xenograft mouse model was used to determine the effect of Harmine treatment on NSCLC in vivo. Western blotting analysis of cell growth and metastasis related signal pathways was conducted to investigate the molecular mechanism of Harmine's inhibitory effect on NSCLC. RESULTS: Harmine treatment effectively inhibited cell proliferation and induced the G1/S cell cycle arrest of NSCLC cells. Further study proved that Harmine treatment led to apoptosis induction. Furthermore, treatment with NSCLC cells with Hamine resulted in decreased cell migration and cell invasion in vitro. More importantly, Harmine treatment significantly suppressed the NSCLC tumor growth and metastasis in mouse xenograft model in vivo. Mechanistically, in Harmine-treated NSCLC cells, RECK expression and its downstream signaling cascade were dramatically activated. As a consequence, the expression level of MMP-9 and E-cadherin were significantly decreased. CONCLUSION: These findings identify Harmine as a promising activator of RECK signaling for metastatic NSCLC treatment.

A Series of ß-Carboline Alkaloids from the Seeds of Peganum harmala Show G-Quadruplex Interactions.

In this study, we screened 17 medicinal plants for binding activity to G-quadruplex d(TTGGGTT)4 by (1)H NMR spectroscopy and found that the crude extract of Peganum harmala L. seeds showed the most potential binding activity. Subsequently, (1)H NMR- and bioassay-guided isolation of the extract of P. harmala L. was performed to obtain four pairs of partially racemized ß-carboline alkaloids, pegaharmines A-D (1-4). Their structures and absolute configurations were determined by extensive NMR analyses, X-ray crystallography, ECD calculations, and CD exciton chirality approaches. Interestingly, pegaharmine D (4), which showed the strongest G-quadruplex interaction, exhibited significant cytotoxic activity against three cancer cell lines. This work contributed a practical strategy for the discovery of novel G-quadruplex ligands from natural products and provided potential insights for using ß-carboline alkaloids as anticancer lead compounds specifically targeting G-quadruplexes.

Novel mechanism of harmaline on inducing G2/M cell cycle arrest and apoptosis by up-regulating Fas/FasL in SGC-7901 cells.

Harmaline (HAR), a natural occurrence ß-carboline alkaloid, was isolated from the seeds of Peganum harmala and exhibited potent antitumor effect. In this study, the anti-gastric tumor effects of HAR were firstly investigated in vitro and in vivo. The results strongly showed that HAR could inhibit tumor cell proliferation and induce G2/M cell cycle arrest accompanied by an increase in apoptotic cell death in SGC-7901 cancer cells. HAR could up-regulate the expressions of cell cycle-related proteins of p-Cdc2, p21, p-p53, Cyclin B and down-regulate the expression of p-Cdc25C. In addition, HAR could up-regulate the expressions of Fas/FasL, activated Caspase-8 and Caspase-3. Moreover, blocking Fas/FasL signaling could markedly inhibit the apoptosis caused by HAR, suggesting that Fas/FasL mediated pathways were involved in HAR-induced apoptosis. Interestingly, HAR could also exert on antitumor activity with a dose of 15 mg/kg/day in vivo, which was also related with cell cycle arrest. These new findings provided a framework for further exploration of HAR which possess the potential antitumor activity by inducing cell cycle arrest and apoptosis.

Peganine hydrochloride dihydrate an orally active antileishmanial agent.

Protozoic infections caused by genus Leishmania pose an enormous public health threat in developing countries, compounded by the toxicity and resistance to current therapies. Under the aegis of our ongoing program on drug discovery and development on antileishmanial agents from plants, we carried out bioassay guided fractionation on Peganum harmala seeds which resulted in the isolation of 1 as an antileishmanial agent. 2D-NMR spectral data and single crystal X-ray crystallography data indicated 1 as peganine hydrochloride in dihydrated form. The compound 1 exhibited in-vitro activity against both extracellular promastigotes as well as intracellular amastigotes residing within murine macrophages in Leishmania donovani. Furthermore, 1 also exhibited in-vivo activity, 79.6 (+/-8.07)% against established VL in hamsters at a dose of 100mg/kgb.wt.

Antitumor and neurotoxic effects of novel harmine derivatives and structure-activity relationship analysis.

Beta-carboline alkaloids such as harmine are present in medicinal plants such as Peganum harmala that have been used as folk medicine in anticancer therapy. In our study, 9 harmine derivatives (including harmine) were investigated for their antitumor effects and acute toxicities in mice, and the structure-activity relationship (SAR) was also analyzed. Administration of these compounds resulted in tumor inhibition rates of 15.3-49.5% in mice bearing Lewis Lung Cancer, sarcoma180 or HepA tumor, with the highest value of 49.5% from compound 6. Acute toxicity studies showed that all these compounds except compounds 2 and 5 caused remarkable acute neurotoxicities manifested by tremble, twitch and jumping. SAR analysis indicated that the formate substitution at R3 of the tricyclic skeleton reduced their neurotoxicity, while the short alkyl or aryl substitution at R9 increased the antitumor activity. The harmine and its derivatives resulted in in vitro cytotoxicity (IC50) values of 0.011-0.021 micromol/ml in HepG2 cells, with compound 8 being the most potent among all agents tested. Compounds 1, 6, 7 and 8 induced apoptosis in HepG2 cells, with the highest apoptotic rate (55.34%) from compound 6. Western blotting analysis demonstrated that compound 6 completely inhibited the expression of Bcl-2 gene, and compounds 1 and 8 produced a significant inhibition by 40 and 60%, respectively, compared to the control, while compound 7 did not alter the level of Bcl-2. Compounds 1, 6, 7 and 8 upregulated the expression of death receptor Fas by approximately 50-120%. All these findings indicate that compounds with both substitutions at R3 and R9 (such as compound 5) have high antitumor activity and low toxicity, which might be chosen as lead molecules for further development. Further studies on the effects of harmine derivatives on key regulators for tumor cell apoptosis are needed.