METHODS: This nanocomposite consists of zinc layered hydroxide intercalated with protocatechuate (an anionic form of protocatechuic acid), that has been synthesized using a direct method with zinc oxide and protocatechuic acid as precursors.
RESULTS: The resulting protocatechuic acid nanocomposite (PAN) showed a basal spacing of 12.7 Å, indicating that protocatechuate was intercalated in a monolayer arrangement, with an angle of 54° from the Z-axis between the interlayers of the zinc layered hydroxide, and an estimated drug loading of about 35.7%. PAN exhibited the properties of a mesoporous type material, with greatly enhanced thermal stability of protocatechuate as compared to its free counterpart. The presence of protocatechuate in the interlayers of the zinc layered hydroxide was further supported by Fourier transform infrared spectroscopy. Protocatechuate was released from PAN in a slow and sustained manner. This mechanism of release was well represented by a pseudo-second order kinetics model. PAN has shown increased cytotoxicity compared to the free form of protocatechuic acid in all cancer cell lines tested. Tumor growth suppression was extensive, particularly in HepG2 and HT29 cell lines.
CONCLUSION: PAN is suitable for use as a controlled release formulation, and our in vitro evidence indicates that PAN is an effective anticancer agent. PAN may have potential as a chemotherapeutic drug for human cancer.
DESIGN: A comprehensive literature review was completed. For this the electronic library databases ASFA, CABD and Scopus were systematically searched and relevant references cited in these sources were carefully analysed. The search terms used were 'fish', 'small fish species', 'micronutrients', 'food-based strategies', 'fish consumption' and 'developing countries'. The quality of data on nutritional analyses was carefully reviewed and data that lacked proper information on methods, units and samples were excluded.
RESULTS: The evidence collected confirmed the high levels of vitamin A, Fe and Zn in some of the small fish species in developing countries. These small fish are reported to be more affordable and accessible than the larger fish and other usual animal-source foods and vegetables. Evidence suggests that these locally available small fish have considerable potential as cost-effective food-based strategies to enhance micronutrient intakes or as a complementary food for undernourished children. However, the present review shows that only a few studies have been able to rigorously assess the impact of fish consumption on improved nutritional status in developing countries.
CONCLUSIONS: Further research is required in areas such as determination of fish consumption patterns of poor households, the nutritional value of local fish and other aquatic animals and the impact of fish intake on improved nutritional status in developing countries where undernutrition is a major public health problem.