Bio-fortification of Brassica micro-greens: towards development of a nutritionally enhanced micro-green melange for non-communicable disease prevention

Background : The term ‘functional food’ received recognition by established sustenance entities in Japan, Europe and the United States (FOSHU, FUFOSE and FDA respectively) despite its existence since the 20 th century (Columbus, Captain’s log, Santa Maria). These entities acknowledge that functional foods are pivotal in promoting human health, beyond basic nutritional requirements, provided it is grounded by scientific and medical credibility. Globally, non-communicable diseases (cancer, diabetes, cardiovascular-, respiratory- and malnutrition-related diseases) are resulting in increased mortality statistics, often a result of inadequate intake of dietary nutrients (malnutrition). Functional foods contain significant amounts of bio-active compounds (such as polyphenols, glucosinolates, phytoestrogens and carotenoids, amongst others) which have been associated with non-communicable disease prevention/treatment. Collectively termed phytochemicals, these bioactive compounds form part of a plant’s secondary metabolite profile and usually accumulate as part of global stress response (both abiotic and biotic) mechanisms. Brassica vegetables and leafy greens (broccoli, brussel sprouts, rocket, kale and mustard, amongst others) are consumed globally, as mature plants/plant parts, due to their association with health promoting benefits and are generally accepted as functional foods. Although plants accumulate phytochemicals ubiquitously, micro-greens (immature plants with 2-4 true leaves) are considered nutritionally superior as they hyper-accumulate phytochemicals (up to 1000 times more than mature plants). We believe that Brassica micro-greens are a potential target for bio-fortification (enhancement of the phytochemical profile) through the use of abiotic environmental stress stimuli. Consequently, human health beneficial micro-green based products could be developed in the functional food sector for their use in prevention of non-communicable diseases. Objective : Establishing a high light-induced bio-fortification strategy to augment the accumulation of bio-active compounds in Brassica micro-greens (rocket, mustard and kale), purposed toward development of a ‘designer’ micro-green melange (functional food product) containing a diverse range of bio-active (disease preventative) compounds. Methods : A selection of Brassica leafy greens (wild rocket, mustard greens and kale) were propagated under high light to micro-green stage (two to four true leaves). Micro-greens were harvested and analysed as either (i) fresh or (ii) lyophilized material. Analyses of extracted phenolic compounds were conducted with high-throughput LC-MS/MS to quantify and/or identify accumulated compounds. Further, antioxidant capacity was determined using the Cu + -reducing CUPRAC method. Extracts from both fresh and lyophilized micro-green tissue were assiduously tested on human breast cancer cell lines (MCF-7) to derive individual and combined anti-cancer potential. Results : The application of high light stimulated micro-greens to accumulate significant amounts of known phytochemicals (quercetin, isorhamnetin) when compared to those grown under a normal light regime. Further, previously undocumented phytochemicals (resveratrol, catechin, epicatechin and kaempferol, amongst others) also accumulated in micro-greens to adequate concentrations required for anti-cancer activity. Plant extracts from bio-fortified micro-greens (derived from either fresh or lyophilized tissue) displayed increased anti-oxidant capacity (up to 3-fold, when compared to normal), a key component in cancer cell apoptosis. Conclusion : Innovative strategies to enhance phytochemical profiles of plants is currently a major focus of the world health organization (WHO), given the significant mortality rates imparted by malnutrition. We describe here a simple method of achieving this goal by environmentally manipulating (using high light) the phytochemical accumulation in a range of well-known Brassica species, at micro-green stage. Fresh produce is not always easily accessible and/or difficult to distribute. We therefore aim to further this idea into product development (using lyophilized material), which could preserve the health beneficial compounds and be readily distributable. Results described here are either for fresh micro-greens or lyophilized material. Outcomes thus far have indicated (i) unambiguous increases in polyphenolic content by high light-stimulation, (ii) accumulation of previously undocumented polyphenolics and, (iii) consequent increases in antioxidant capacity.  Lyophilisation did not alter the antioxidant potential. Ongoing in vitro investigations are being conducted to determine the chemoprotective effects of lyophilized microgreen extracts on a range of cancer cell lines, and we propose that this system of phytochemical enhancement could potentially generate a non-genetically modified, bio-fortified product (either in fresh or lyophilized form) to be used as a functional food/food product featuring in preventative strategies regarding non-communicable diseases. Keywords : Brassica, Micro-greens, Non-communicable diseases, Phytochemicals How to cite this abstract:  Loedolff B., Stander M., Peters S., Kossmann J.; FFC’s 22 nd International Conference; Boston, MA, USA; Organized by FFC and BIDMC/ Harvard Medical School Teaching Hospital; Volume 1; Supplement 1: 176-179