A study of the literature indicates that chloroplasts synthesise a range of molecules, many of which have nutritional value for humans, but the nutritional credentials of chloroplasts recovered from plant cells are not established. Chloroplast-rich-fractions (CRFs) were prepared from green plant species and the macro- and micro-nutrient composition compared with the whole leaf materials (WLMs). The results indicated that, on a dry weight basis, CRF material from a range of green biomass was enriched in lipids and proteins, and in a range of micronutrients compared with the WLM. Vitamins E, pro-vitamin A, and lutein were all greater in CRF preparations. Of the minerals, iron was most notably concentrated in CRF. Spinach CRFs possessed the highest α-tocopherol [62 mg 100 g-1, dry weight (DW)], β-carotene (336 mg 100 g-1 DW) and lutein (341 mg 100 g-1 DW) contents, whilst grass CRFs had the highest concentration of alpha-linolenic acid (ALA) (69.5 mg g-1). The higher concentrations of α-tocopherol, β-carotene, lutein, ALA and trace minerals (Fe and Mn) in CRFs suggested their potential use as concentrated ingredients in food formulations deficient in these nutrients.
Rosmarinic acid (RA) is a highly valued natural phenolic compound that is very commonly found in plants of the families Lamiaceae and Boraginaceae, including Coleus blumei, Heliotropium foertherianum, Rosmarinus officinalis, Perilla frutescens, and Salvia officinalis. RA is also found in other members of higher plant families and in some fern and horned liverwort species. The biosynthesis of RA is catalyzed by the enzymes phenylalanine ammonia lyase and cytochrome P450-dependent hydroxylase using the amino acids tyrosine and phenylalanine. Chemically, RA can be produced via methods involving the esterification of 3,4-dihydroxyphenyllactic acid and caffeic acid. Some of the derivatives of RA include melitric acid, salvianolic acid, lithospermic acid, and yunnaneic acid. In plants, RA is known to have growth-promoting and defensive roles. Studies have elucidated the varied pharmacological potential of RA and its derived molecules, including anticancer, antiangiogenic, anti-inflammatory, antioxidant, and antimicrobial activities. The demand for RA is therefore, very high in the pharmaceutical industry, but this demand cannot be met by plants alone because RA content in plant organs is very low. Further, many plants that synthesize RA are under threat and near extinction owing to biodiversity loss caused by unscientific harvesting, over-collection, environmental changes, and other inherent features. Moreover, the chemical synthesis of RA is complicated and expensive. Alternative approaches using biotechnological methodologies could overcome these problems. This review provides the state of the art information on the chemistry, sources, and biosynthetic pathways of RA, as well as its anticancer properties against different cancer types. Biotechnological methods are also discussed for producing RA using plant cell, tissue, and organ cultures and hairy-root cultures using flasks and bioreactors. The recent developments and applications of the functional genomics approach and heterologous production of RA in microbes are also highlighted. This chapter will be of benefit to readers aiming to design studies on RA and its applicability as an anticancer agent.
KEY MESSAGE: Transcript profiling during the early induction phase of oil palm tissue culture and RNAi studies in a model somatic embryogenesis system showed that EgENOD93 expression is essential for somatic embryogenesis. Micropropagation of oil palm through tissue culture is vital for the generation of superior and uniform elite planting materials. Studies were carried out to identify genes to distinguish between leaf explants with the potential to develop into embryogenic or non-embryogenic callus. Oil palm cDNA microarrays were co-hybridized with cDNA probes of reference tissue, separately with embryo forming (media T527) and non-embryo (media T694) forming leaf explants sampled at Day 7, Day 14 and Day 21. Analysis of the normalized datasets has identified 77, 115 and 127 significantly differentially expressed genes at Day 7, Day 14, and Day 21, respectively. An early nodulin 93 protein gene (ENOD93), was highly expressed at Day 7, Day 14, and Day 21 and in callus (media T527), as assessed by RT-qPCR. Validation of EgENOD93 across tissue culture lines of different genetic background and media composition showed the potential of this gene as an embryogenic marker. In situ RNA hybridization and functional characterization in Medicago truncatula provided additional evidence that ENOD93 is essential for somatic embryogenesis. This study supports the suitability of EgENOD93 as a marker to predict the potential of leaf explants to produce embryogenic callus. Crosstalk among stresses, auxin, and Nod-factor like signalling molecules likely induces the expression of EgENOD93 for embryogenic callus formation.