LC-MS/MS method for the determination of haemanthamine in rat plasma, bile and urine and its application to a pilot pharmacokinetic study

Current developments in LC-MS for pharmaceutical analysis

Liquid chromatography (LC) based techniques in combination with mass spectrometry (MS) detection have had a large impact on the development of new pharmaceuticals in the past decades.

The Genus Nerine Herb. (Amaryllidaceae): Ethnobotany, Phytochemistry, and Biological Activity

Nerine Herbert, family Amaryllidaceae, is a genus of about 30 species that are native to South Africa, Botswana, Lesotho, Namibia, and Swatini (formerly known as Swaziland). Species of Nerine are autumn-flowering, perennial, bulbous plants, which inhabit areas with summer rainfall and cool, dry winters. Most Nerine species have been cultivated for their elegant flowers, presenting a source of innumerable horticultural hybrids. For many years, species of Nerine have been subjected to extensive phytochemical and pharmacological investigations, which resulted in either the isolation or identification of more than fifty Amaryllidaceae alkaloids belonging to different structural types. Amaryllidaceae alkaloids are frequently studied for their interesting biological properties, including antiviral, antibacterial, antitumor, antifungal, antimalarial, analgesic, cytotoxic, and cholinesterase inhibition activities. The present review aims to summarize comprehensively the research that has been reported on the phytochemistry and pharmacology of the genus Nerine.

The Amaryllidaceae Alkaloid Haemanthamine Binds the Eukaryotic Ribosome to Repress Cancer Cell Growth

Alkaloids isolated from the Amaryllidaceae plants have potential as therapeutics for treating human diseases. Haemanthamine has been studied as a novel anticancer agent due to its ability to overcome cancer cell resistance to apoptosis. Biochemical experiments have suggested that hemanthamine targets the ribosome. However, a structural characterization of its mechanism has been missing. Here we present the 3.1 Å resolution X-ray structure of haemanthamine bound to the Saccharomyces cerevisiae 80S ribosome. This structure reveals that haemanthamine targets the A-site cleft on the large ribosomal subunit rearranging rRNA to halt the elongation phase of translation. Furthermore, we provide evidence that haemanthamine and other Amaryllidaceae alkaloids also inhibit specifically ribosome biogenesis, triggering nucleolar stress response and leading to p53 stabilization in cancer cells. Together with a computer-aided interpretation of existing structure-activity relationships of Amaryllidaceae alkaloids congeners, we provide a rationale for designing molecules with enhanced potencies and reduced toxicities.

Haemanthamine alters sodium butyrate-induced histone acetylation, p21WAF1/Cip1 expression, Chk1 and Chk2 activation and leads to increased growth inhibition and death in A2780 ovarian cancer cells

BACKGROUND

Haemanthamine (HA) and sodium butyrate (NaB) are promising candidates for chemotherapy as a treatment for cancer.

PURPOSE

We aimed to determine the anticancer potential of HA and NaB, alone and in combination, in A2780 ovarian cancer cells and concurrently investigated anticancer potential in contrast to non-cancer human MRC-5 fibroblasts.

METHODS

Antiproliferative effects were determined by WST-1 assay and by Trypan blue exclusion staining. Cell cycle distributions were studied by flow cytometry and protein levels were determined by Western blotting.

RESULTS

The combination of HA and NaB caused a significant decrease in the proliferation of A2780 cells compared to the stand-alone treatment of cells by HA or NaB. This effect was less pronounced in non-cancer MRC-5 fibroblasts. In the later intervals, the number of A2780 living cells was strongly decreased by treatment using a combination of NaB and HA. This simultaneous application had no considerable effect in MRC-5 fibroblasts. The combination of NaB and HA led to the suppression of cells in the G1 phase and caused an accumulation of cells in the S and G2 phase in comparison to those treated with NaB and HA alone. Treatment of cells with NaB alone led to the activation of proteins regulating the cell cycle. Notably, p21^WAF1/Cip1 was upregulated in both A2780 and MRC-5 cells, while checkpoint kinases 1 and 2 were activated via phosphorylation only in A2780 cells. Unexpectedly, NaB in combination with HA suppressed the phosphorylation of Chk2 on threonine 68 and Chk1 on serine 345 in A2780 cells and downregulated p21^WAF1/Cip1 in both tested cell lines. The sensitization of cells to HA and NaB treatment seems to be accompanied by increased histone acetylation. NaB-induced acetylation of histone H3 and H4 and histone acetylation increased markedly when a combination of NaB and HA was applied. Whereas the most prominent hyperacetylation after HA and NaB treatment was observed in A2780 cells, the acetylation of histones occurred in both cell lines.

CONCLUSION

In summary, we have demonstrated the enhanced activity of HA and NaB against A2780 cancer cells, while eliciting no such effect in non-cancer MRC-5 cells.

Anticancer potential of Amaryllidaceae alkaloids evaluated by screening with a panel of human cells, real-time cellular analysis and Ehrlich tumor-bearing mice

In this study, twenty-two Amaryllidaceae alkaloids were screened for their anticancer potential. All isolates were evaluated for antiproliferative activities on a panel of 17 human cell types of different tissue origin using WST-1 assay. In addition, we determined the antiproliferative effect with a real-time cell analysis xCELLigence system. Thereafter, to evaluate the barely known in vivo anticancer potential of the most potent molecule haemanthamine, a preliminary study was performed using an Ehrlich tumor-bearing mice model. The results showed that haemanthamine, lycorine and haemanthidine exerted the highest antiproliferative activity. The mean growth percent (GP) value after a single-dose 10 μM treatment was for haemanthamine 21%, for lycorine 21% and for haemanthidine 27% that of untreated control cells (100%). Furthermore, haemanthamine, lycorine and haemanthidine exhibited significant cytotoxicities against all the tested cell lines with individual IC₅₀ values in the micromolar range. Dynamic real-time measures of impedance by xCELLigence indicated that these three compounds suppress cell proliferation after 10 h of treatment at a concentration of 10 μM or higher. Regrettably, in a follow-up in vivo antitumor activity study, haemanthamine showed no statistically significant reduction in the tumor size with no prolongation of survival time of Ehrlich tumor-bearing mice. Taken together, these results provide a new clue and guidance for exploiting Amaryllidaceae alkaloids as anticancer agents.

The Biological Activity of Alkaloids from the Amaryllidaceae: From Cholinesterases Inhibition to Anticancer Activity

Modern research has shown that Amaryllidaceae alkaloids represent a rich reservoir of potential small chemical molecules exhibiting several medicinal properties through various mechanisms. Among the many Amaryllidaceae compounds, galanthamine has been given a great amount of attention due to the fact that it possesses potent acetylcholinesterase inhibitory activity. In spite of the amount of evidence indicating the potential usefulness of Amaryllidaceae alkaloids in therapy, research groups have focused their attention on the other alkaloids present in this plant family. New investigations have shed light on many aspects of the structure of Amaryllidaceae alkaloids and on their semisynthetic modification, function, and mechanisms underlying in vitro and in vivo activity. In addition, Amaryllidaceae alkaloids have frequently been identified as having promising cytotoxic properties against cancer cell lines. While follow-up studies have repeatedly shown that Amaryllidaceae alkaloids and their derivatives demonstrate antiproliferative, cytotoxic and apoptosis-inducing activity, the mechanisms remain unclear. This review addresses the most important Amaryllidaceae alkaloids with anticancer potential, particularly those that have been studied for the purpose of gaining a better understanding of the basis of the activity at the cellular and molecular level.