Are the Traditional Medical Uses of Muricidae Molluscs Substantiated by Their Pharmacological Properties and Bioactive Compounds?

Marine molluscs from the family Muricidae hold great potential for development as a source of therapeutically useful compounds. Traditionally known for the production of the ancient dye Tyrian purple, these molluscs also form the basis of some rare traditional medicines that have been used for thousands of years. Whilst these traditional and alternative medicines have not been chemically analysed or tested for efficacy in controlled clinical trials, a significant amount of independent research has documented the biological activity of extracts and compounds from these snails. In particular, Muricidae produce a suite of brominated indoles with anti-inflammatory, anti-cancer and steroidogenic activity, as well as choline esters with muscle-relaxing and pain relieving properties. These compounds could explain some of the traditional uses in wound healing, stomach pain and menstrual problems. However, the principle source of bioactive compounds is from the hypobranchial gland, whilst the shell and operculum are the main source used in most traditional remedies. Thus further research is required to understand this discrepancy and to optimise a quality controlled natural medicine from Muricidae.

An in vitro high-throughput assay for screening reproductive and toxic effects of anticancer compounds.

An in vitro assay was developed that simultaneously tested the effects of anticancer drug candidates on cytotoxicity, hormone synthesis, and gonadotrophin responsiveness using the choriocarcinoma JAr cell line. JAr culture conditions were optimized and then cells were exposed to a marine mollusc extract in the presence and absence of hCG. The intra- and interassay coefficients of variation of the optimized 1 H thiazolyl blue tetrazolium bromide assay were 11.3% and 10.9%, respectively. hCG (1,000 mIU/mL) increased progesterone (P4) synthesis after 24 H (P<0.05). The mollusc extract significantly decreased cell viability, with the IC50 affected by incubation time, but not hCG. P4 synthesis was inhibited at low concentrations of the anticancer extract, but stimulated at the highest concentration, and complex interactions of P4 were also found with hCG. In conclusion, the optimized assay is useful to characterize the effects of novel drugs on cytotoxicity, basal, and gonadotrophin-stimulated P4 synthesis in vitro, and can be used to inform subsequent in vivo studies.

Marine compounds selectively induce apoptosis in female reproductive cancer cells but not in primary-derived human reproductive granulosa cells.

Anticancer properties of tyrindoleninone and 6-bromoisatin from Dicathais orbita were tested against physiologically normal primary human granulosa cells (HGC) and reproductive cancer cell lines. Tyrindoleninone reduced cancer cell viability with IC50 values of 39 µM (KGN; a tumour-derived granulosa cell line), 39 µM (JAr), and 156 µM (OVCAR-3), compared to 3516 µM in HGC. Apoptosis in HGC's occurred after 4 h at 391 µM tyrindoleninone compared to 20 µM in KGN cells. Differences in apoptosis between HGC and KGN cells were confirmed by TUNEL, with 66 and 31% apoptotic nuclei at 4 h in KGN and HGC, respectively. These marine compounds therefore have potential for development as treatments for female reproductive cancers.

Development of an in vitro reproductive screening assay for novel pharmaceutical compounds.

An in vitro reproductive cell-based toxicity assay was developed using MLTC-1 (murine Leydig tumour cell line) in order to examine the reproductive toxicity of two novel nanopharmaceutical compounds, namely ethylene glycol mono allyl ether and poly(ethylene glycol) octa-functionalized polyhedral oligomeric silsesquioxane. Three commonly used cytotoxicity assays, namely the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide], MTS [3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium] and Crystal Violet assays, were compared, and the MTT assay proved to be the most accurate and reproducible for the MLTC-1 cell line. The doubling rate of the MLTC-1 cells was 30+/-3.5 h and the optimal seeding density for the MTT assay was 20000 cells per well, and the optimized MTT assay utilized a 4 h cell adherence followed by incubation with 0.5 mg/ml MTT for 1 h. The intra- and inter-assay CV (coefficient of variation) values were 12.3 and 11% respectively. MLTC-1 cells only produce the reproductive hormone progesterone in response to hCG (human chorionic gonadotropin), which stimulated progesterone production dose-dependently from 0 to 100 m.i.u. (milliinternational units)/ml (2706+/-1118 ng/ml). H(2)O(2) as a negative control killed 100% of cells at 1000 microg/ml. The two nanopharmaceutical compounds were cytotoxic at concentrations > or =0.1 microg/ml, but hCG decreased cytotoxicity to > or =1000 microg/ml (P<0.001). hCG-stimulated progesterone synthesis afforded some protection against the cytotoxic effects of the two novel nanotechnology compounds; therefore doses < or =100 microg/ml and an exposure period of 1 h would be recommended for testing in in vivo animal reproductive assays.