ABSTRACT
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.
ABSTRACT
Marine molluscs and their bioactive compounds are of particular relevance to the growing pool of nutraceutical resources under global investigation. A number of extraction techniques have been developed to isolate bioactive compounds according to their chemical characterization, such as proteins, carbohydrates and lipids. We briefly reviewed those methods in general. Bioactive molecules are 'concealed' in the primary structures of tissue samples of molluscs as amino acids, lipids or carbohydrates which are released by mechanical and chemical processes. The major health benefits of extracts of molluscs include antioxidant, anticancer, and anti-infectious disease activities and cardiovascular protection, which have been reviewed in detail. This review provides a novel view into the efficacy of isolation techniques and subsequent bioactivity analysis of compounds under investigation. Future development in extraction-bioactivity has also been discussed.
Subject(s)
Carbohydrates/isolation & purification , Food Analysis/methods , Lipids/isolation & purification , Mollusca/chemistry , Proteins/isolation & purification , Shellfish/analysis , Animals , Carbohydrates/chemistry , Lipids/chemistry , Proteins/chemistryABSTRACT
In this study, we examined the cytotoxic effects of four fractions from three species of New Zealand (NZ) surf clam on four common organ cancer cells. In most cases, a dose- and time-dependent inhibition on the proliferation of the cancer cells was observed. This was most significant in WiDr (colon) cells, where the percentages of viability reduced to as low as 6%, 5%, and 17% (at 1000 µg 72 h) by extracts from Diamond shell, Storm shell, and Tua tua species, respectively. A549 (lung) cells were the least susceptible to the treatment, with viability percentages at 82%, 15%, and 45%, under the same conditions. Induction of caspase-dependent apoptosis and alterations to the cell cycle further supported the observed morphological analysis. The ethanol, petroleum ether, and ethyl acetate fractions of NZ surf clam, rich in lipids and proteins, were more potent than their water-based counterpart. This is the first demonstration where extracts from NZ surf clams show the ability to inhibit the growth and proliferation of cancer cell lines. We suggest that NZ surf clam extracts have the potential to be further studied and developed as candidates for cancer supplementary management/treatment.
ABSTRACT
The antioxidant action of three New Zealand surf clams was evaluated for the first time. Aqueous (cd) and ethanolic extracts from Diamond shell - Crassula aequilatera, Storm shell - Mactra murchisoni, and Tua tua - Paphies donacina were studied for their antioxidant potentials using two in vitro assays. The ethanolic extracts were further fractioned into four parts; petroleum ether (pe), ethyl acetate (ea), n-butanol (nb), and the final aqueous fraction (w). Comparing among all fractions tested, the ea fraction of P. donacina showed the strongest free radical scavenging power, with a radical scavenging activity of 76.14% at 20µg/mL. The ea fraction of C. aequilatera had the highest copper reducing activity with an absorbance of 1.596 at 20µg/mL. Results from this study suggest that some bioactive compounds with significant antioxidant effects may exist in the New Zealand surf clams, and could potentially reduce oxidative stress to deliver health benefits or to produce functional foods.
