Cytotoxicity of Extracts from New Zealand Surf Clams Against Organ Cancer Cell Lines

Sulphated glycosaminoglycan isolated from the edible slipper oyster Magallana bilineata (Röding, 1798) attenuates inflammatory cytokines on lipopolysaccharide-prompted macrophages

The slipper oyster Magallana bilineata (Ostreidae) is considered as culinary delicacy among marine bivalves, and a sulphated glycosaminoglycan, 4,6-O-SO3-β-(1→3)-GalNAcp (unit A) and β-(1→4)-GlcAp (unit B) as principle structural motif containing laterally branched 4-O-SO3-β-glucopyranose (unit C) (MBP-3) was isolated from this species. Nuclear magnetic resonance (NMR), Fourier transform infra-red (FTIR), and mass spectroscopy techniques were used to characterise MBP-3. MBP-3 exhibited anti-inflammatory activities against inflammatory 5-lipoxygenase (IC50 0.11 mg mL-1) and cyclooxygenase-2 (IC50 0.12 mg mL-1) enzymes. MBP-3 (at 100 μg mL-1) showed effective downregulation against pro-inflammatory cytokines generation, namely interleukins-6, 1β, (IL-6, 1β) (1-1.7 pg mL-1) and tumour necrosis factor-α (TNF-α) (4 pg mL-1) along with substantial downregulation of ROS production in lipopolysaccharide (LPS)-inflamed cells. MBP-3 blocked the mRNA of NF-κB, cyclooxygenase-2 (COX-2), and other cytokines, in lipopolysaccharide-induced macrophages. The potential to constrain inflammatory cytokine production revealed its application to develop functional food to attenuate inflammation-associated disorders.

Effects of preparation method on the biochemical characterization and cytotoxic activity of New Zealand surf clam extracts

Molluscan extracts confer a wide range of health promoting properties, one of them is cytotoxicity. Extraction and processing can affect the efficacy and properties of bioactive molecules. New Zealand (NZ) surf clams have never been thoroughly studied for bioactives until recently. However, the effect of cold and heat extraction procedure on biochemical composition and cytotoxic activities of NZ surf clam remains unanswered. The objective is to compare the effects on cytotoxicity of three NZ surf clams (Diamond shell, Crassula aequilatera; Storm shell, Mactra murchisoni; and Deepwater Tua tua, Paphies donacina) extracts via cold or heat process across cancer cell lines to find out which process can preserve bioactivity better. Fractions of extracts prepared via cold or heat procedures were tested for cell growth inhibition, apoptosis induction and cell cycle arrest in seven cancer cell lines. Apoptosis was induced through all cell lines, as further evidenced in Caspase-3/7 activities. Cell cycle arrest was focused on G2/M- and S- phases. Petroleum ether and ethyl acetate fractions, with the greatest bioactivity in this study, are rich in lipids and proteins, indicating likely bioactive sources. Cold preparation was responsible for the lowest cancer cell viability and induced greater apoptosis. Cold process retained better bioactivity/cytotoxicity than that of heat-processed extracts. This information may guide future health/nutraceutical clam product development.