A novel and practical synthetic route for the total synthesis of lycopene

The sources, properties, extraction, biosynthesis, pharmacology, and application of lycopene

Lycopene is an important pigment with an alkene skeleton from Lycopersicon esculentum, which is also obtained from some red fruits and vegetables. Lycopene is used in the food field with rich functions and serves in the medical field with multiple clinical values because it has dual functions of both medicine and food. It was found that lycopene was mainly isolated by solvent extraction, ultrasonic-assisted extraction, supercritical fluid extraction, high-intensity pulsed electric field-assisted extraction, enzymatic-assisted extraction, and microwave-assisted extraction. Meanwhile, it was also obtained via 2 synthetic pathways: chemical synthesis and biosynthesis. Pharmacological studies revealed that lycopene has anti-oxidant, hypolipidemic, anti-cancer, immunity-enhancing, hepatoprotective, hypoglycemic, cardiovascular-protective, anti-inflammatory, neuroprotective, and osteoporosis-inhibiting effects. The application of lycopene mainly includes food processing, animal breeding, and medical cosmetology fields. It is hoped that this review will provide some useful information and guidance for future study and exploitation of lycopene.

A Modular Approach for the Synthesis of Natural and Artificial Terpenoids

Many terpenoids with isoprene unit(s) demonstrating critical biological activities have been isolated and characterized. In this study, we have developed a robust chem-stamp strategy for the construction of the key isoprene unit, which consists of two steps: one-carbon extension of aldehydes to the alkenyl boronates by the boron-Wittig reaction and the rhodium-catalyzed reaction of alkenyl boronates with 2,3-allenols to yield enals. This chem-stamp could readily be applied repeatedly and separately, enabling the modular concise synthesis of many natural and pharmaceutically active terpenoids, including retinal, β-carotene, vitamin A, tretinoin, fenretinide, acitretin, ALRT1550, nigerapyrone C, peretinoin, and lycopene. Owing to the diversified availability of the starting materials, aldehydes and 2,3-allenols, creation of new non-natural terpenoids has been realized from four dimensions: the number of isoprene units, the side chain, and the two terminal groups.

Waste and by-products as sources of lycopene, phytoene, and phytofluene - Integrative review with bibliometric analysis

Food loss and waste are severe social, economic, and environmental issues. An example is the incorrect handling of waste or by-products used to obtain bioactive compounds, such as carotenoids. This review aimed to present a comprehensive overview of research on lycopene, phytoene, and phytofluene obtained from waste and by-products. In this study, an integrative literature approach was coupled with bibliometric analysis to provide a broad perspective of the topic. PRISMA guidelines were used to search studies in the Web of Science database systematically. Articles were included if (1) employed waste or by-products to obtain lycopene, phytoene, and phytofluene or (2) performed applications of the carotenoids previously extracted from waste sources. Two hundred and four articles were included in the study, and the prevalent theme was research on the recovery of lycopene from tomato processing. However, the scarcity of studies on colorless carotenoids (phytoene and phytofluene) was evidenced, although these are generally associated with lycopene. Different technologies were used to extract lycopene from plant matrices, with a clear current trend toward choosing environmentally friendly alternatives. Microbial production of carotenoids from various wastes is a highly competitive alternative to conventional processes. The results described here can guide future forays into the subject, especially regarding research on phytoene and phytofluene, potential and untapped sources of carotenoids from waste and by-products, and in choosing more efficient, safe, and environmentally sustainable extraction protocols.

A mechanistic updated overview on lycopene as potential anticancer agent

The potent relation between lycopene intake and reduced incidence of a variety of cancers has an increasing interest. This comprehensive review aims to highlight the in vivo and in vitro research evaluating the anticancer mechanisms of lycopene by underlining the experiment conditions. In addition to these, the general characterization of lycopene has been explained. A collection of relevant scientific pharmacological articles from the following databases PubMed/MedLine, Web of Science, Scopus, TRIP database, and Google Scholar on the mechanisms of anticancer molecular action and cellular effects of lycopene in various types of tumors was performed. The anticancer potential of lycopene has been described by various in vitro cells, animal studies, and some clinical trials. It has been revealed that the anticancer potential of lycopene is mainly due to its powerful singlet-oxygen quencher characteristics, simulation of detoxifying/antioxidant enzymes production, initiation of apoptosis, inhibition of cell proliferation and cell cycle progression as well as modulations of gap junctional communication, the growth factors, and signal transduction pathways. It has been highlighted that the anticancer properties of lycopene are primarily linked to factors including; dose, presence of drug delivery systems, type of cancer, tumor size, and treatment time.

Novel carotenogenic gene combinations from red yeasts enhanced lycopene and beta-carotene production in Saccharomyces cerevisiae from the low-cost substrate sucrose

Carotenoids (C40H56) including lycopene and beta-carotene are relatively strong antioxidants that provide benefits to human health. Here, we screened highly efficient crt variants from red yeasts to improve lycopene and beta-carotene production in Saccharomyces cerevisiae. We identified that crt variants from Sporidiobolus pararoseus TBRC-BCC 63403 isolated from rice leaf in Thailand exhibited the highest activity in term of lycopene and beta-carotene production in the context of yeast. Specifically, the phytoene desaturase SpCrtI possessed up to 4-fold higher in vivo activity based on lycopene content than the benchmark enzyme BtCrtI from Blakeslea trispora in our engineered WWY005 strain. Also, the geranylgeranyl pyrophosphate (GGPP) synthase SpCrtE, the bifunctional phytoene synthase-lycopene cyclase SpCrtYB, and SpCrtI when combined led to 7-fold improvement in beta-carotene content over the benchmark enzymes from Xanthophyllomyces dendrorhous in the laboratory strain CEN.PK2-1C. Sucrose as an alternative to glucose was found to enhance lycopene production in cells lacking GAL80. Lastly, we demonstrated a step-wise improvement in lycopene production from shake-flasks to a 5-L fermenter using the strain with GAL80 intact. Altogether, our study represents novel findings on more effective crt genes from Sp. pararoseus over the previously reported benchmark genes and their potential applications in scale-up lycopene production.

Synthesis of Ferulenol by Engineered Escherichia coli: Structural Elucidation by Using the In Silico Tools

4-Hydroxycoumarin (4HC) has been used as a lead compound for the chemical synthesis of various bioactive substances and drugs. Its prenylated derivatives exhibit potent antibacterial, antitubercular, anticoagulant, and anti-cancer activities. In doing this, E. coli BL21(DE3)pLysS strain was engineered as the in vivo prenylation system to produce the farnesyl derivatives of 4HC by coexpressing the genes encoding Aspergillus terreus aromatic prenyltransferase (AtaPT) and truncated 1-deoxy-D-xylose 5-phosphate synthase of Croton stellatopilosus (CstDXS), where 4HC was the fed precursor. Based on the high-resolution LC-ESI(±)-QTOF-MS/MS with the use of in silico tools (e.g., MetFrag, SIRIUS (version 4.8.2), CSI:FingerID, and CANOPUS), the first major prenylated product (named compound-1) was detected and ultimately elucidated as ferulenol, in which information concerning the correct molecular formula, chemical structure, substructures, and classifications were obtained. The prenylated product (named compound-2) was also detected as the minor product, where this structure proposed to be the isomeric structure of ferulenol formed via the tautomerization. Note that both products were secreted into the culture medium of the recombinant E. coli and could be produced without the external supply of prenyl precursors. The results suggested the potential use of this engineered pathway for synthesizing the farnesylated-4HC derivatives, especially ferulenol.

Opportunities and challenges for the sustainable production of structurally complex diterpenoids in recombinant microbial systems

With over 50.000 identified compounds terpenes are the largest and most structurally diverse group of natural products. They are ubiquitous in bacteria, plants, animals and fungi, conducting several biological functions such as cell wall components or defense mechanisms. Industrial applications entail among others pharmaceuticals, food additives, vitamins, fragrances, fuels and fuel additives. Central building blocks of all terpenes are the isoprenoid compounds isopentenyl diphosphate and dimethylallyl diphosphate. Bacteria like Escherichia coli harbor a native metabolic pathway for these isoprenoids that is quite amenable for genetic engineering. Together with recombinant terpene biosynthesis modules, they are very suitable hosts for heterologous production of high value terpenes. Yet, in contrast to the number of extracted and characterized terpenes, little is known about the specific biosynthetic enzymes that are involved especially in the formation of highly functionalized compounds. Novel approaches discussed in this review include metabolic engineering as well as site-directed mutagenesis to expand the natural terpene landscape. Focusing mainly on the validation of successful integration of engineered biosynthetic pathways into optimized terpene producing Escherichia coli, this review shall give an insight in recent progresses regarding manipulation of mostly diterpene synthases.

Synthesis of a Series of γ-Keto Allyl Phosphonates

Under solvent-free conditions and at 80 °C, a DMAP- or imidazole-mediated clean and rapid conversion of cyclic Morita-Baylis-Hillman (MBH) acetates into the corresponding γ-keto allyl phosphonates in 70-93% yields is described herein. This allylic nucleophilic substitution works well with primary and secondary acetates bearing, at the β'-position, linear or branched alkyl groups and aryl groups.

Effects of various factors of ultrasonic treatment on the extraction yield of all-trans-lycopene from red grapefruit (Citrus paradise Macf.)

The effects of various factors, including the extraction time, temperature, solvent/material ratio, the ultrasonic intensity and duty cycle of ultrasonic irradiation on the extraction yield of all-trans-lycopene from red grapefruit by ultrasound-assisted extraction (UAE) were investigated. In comparison with conventional solvent extraction (CSE), UAE showed a pronounced greater extraction yield and reduced extraction time effectively with a peak value at 30 min. The extraction yield was significantly influenced by temperature and the optimum condition was 30 °C. The extraction yield increased with increasing of solvent/material ratio until equilibrium was arrived at the optimal ratio of 3:1 (mL/g). The extraction yield increased first and then decreased with an increase in ultrasonic intensity. The extraction yield of UAE increased with the increase of duty cycle, whereas pulsed ultrasound with proper intervals was more efficient than continuous ultrasonication. The degradation via isomerisation of all-trans-lycopene under ultrasonic treatment was also observed with the formation of 9,13'-di-cis-, 9,13-di-cis-, 15-cis-, 13-cis- and 9-cis-lycopene isomers which were tentatively identified by HPLC-PAD.

Spectroscopic characterization of lycopene extract from Lycopersicum esculentum (Tomato) and its evaluation as a chemopreventive agent against experimental hepatocarcinogenesis in mice

The present study was designed to characterize the lycopene extract (LycT) prepared from tomatoes (Lycopersicum esculentum) and then to evaluate its chemopreventive efficacy in N-diethylnitrosamine (NDEA)-induced experimental hepatocarcinogenesis in female Balb/c mice. The extraction of lycopene was carried out using hexane/acetone/ethanol as an extracting medium and then characterized by ultraviolet-visible, nuclear magnetic resonance and Fourier transform infrared spectroscopy. Chemopreventive efficacy of characterized LycT in vivo was evaluated in terms of hepatic tumour incidence, multiplicity, burden, hepatosomatic index and animal survival rate. Results indicated that average lycopene content of the tomato was 11.6-14 mg/kg tomato weight. Spectroscopic data confirmed the structural characteristics of lycopene in the extract. In the animal study, reduction in tumour incidence (42.05%), tumour burden (1.39) and tumour multiplicity (3.42) was observed upon LycT pretreatment to NDEA-treated animals. Histopathological analysis unravelled that the increased survival rate in LycT + NDEA-treated animals was due to the delay in the formation of aggressive tumour nodules. These observations indicate that lycopene seems to be an able candidate for chemoprevention in hepatocarcinogenesis resulting from NDEA insults.