Efficient solvent extraction of antioxidant-rich extract from a tropical diatom,Chaetoceros calcitrans (Paulsen) Takano 1968

Objective: To compare the in vitro antioxidant capacity of a diatom, Chaetoceros calcitrans(C. calcitrans) extracted using six types of solvents.Methods: Each extract was evaluated in terms of extraction yield, total carotenoid,fucoxanthin content, total phenolic and antioxidant capacities(DPPH and ABTS +scavenging activity and iron chelating activity).Results: The methanol extract exhibited the highest yield [(22.71 ± 0.96) g/100 g dry weight(DW)], total carotenoid [(4.46 ± 0.36) mg/g DW], total phenolic [(2.49 ± 0.08) mg gallic acid equivalents/g DW] and second highest fucoxanthin content [(2.08 ± 0.03) mg fucoxanthin/g DW] as compared to other solvent extracts. Methanolic extract also exhibited significantly higher(P < 0.05) scavenging(DPPH, ABTS +) and iron chelating activities.Conclusions: Methanol was the recommended solvent for the production of antioxidant rich extract from C. calcitrans. Both carotenoids and phenolic acids were found to be positively correlated to the antioxidant capacities of C. calcitrans. Lead bioactives confirmed by subsequent high performance liquid chromatography studies were fucoxanthin, gallic acid and protocatechuic acid.

A review on current and future advancements for commercialized microalgae species

Microalgae are unicellular photosynthetic microorganisms that are commonly found in saline or freshwater environments.Over the years,microalgae represent promising sources of sustainable bioactivities with past literatures reflecting a growing interest in algae-based dietary supplements in the form of whole biomass.Notably,the bioactive molecules that can be identified and extracted in microalgae have scientifically proven to contain therapeutic properties which can be beneficial to human health.With the increasing occurrence of global health threats such as antimicrobial resistance and cancer,this has resulted in considerable attention for microalgae study especially in the medicinal field.Although studies have proved the therapeutic potentials of high-value bioproducts in microalgae,however,there is still room to understand their potential therapeutic properties on humans’health,discovering novel microalgae-derived bioactive compounds,as well as translating the lab-based evidence to clinical trial studies.This review will focus on accessing the biochemical compositions of commercialised microalgae species from 2007 to 2020,and the activity of their biologically active molecules in eliciting selected therapeutic potentials which are anti-oxidative,anti-inflammatory,anti-microbial and anti-cancer properties.This review article will also be looking at the research gaps in addition to the above four major selected therapeutic potentials,and future prospective.