An improved method for the separation of carotenoids and carotenoid isomers by liquid chromatography-mass spectrometry

A Scoping Review on Carotenoid Profiling in Passiflora spp.: A Vast Avenue for Expanding the Knowledge on the Species

The Passiflora genus is recognised for its ethnopharmacological, sensorial, and nutritional significance. Yet, the screening of its dietary and bioactive molecules has mainly targeted hydrophilic metabolites. Following the PRISMA-P protocol, this review assessed the current knowledge on carotenoid composition and analysis within Passiflora, examining 968 records from seven databases and including 17 studies focusing on carotenoid separation and identification in plant parts. Those publications originated in America and Asia. P. edulis was the most frequently examined species of a total of ten, while pulp was the most studied plant part (16 studies). Carotenoid analysis involved primarily high-performance liquid chromatography separation on C18 columns and detection using diode array detectors (64.71%). Most studies identified the provitamin A β-carotene and xanthophylls lutein and zeaxanthin, with their geometric configuration often neglected. Only one study described carotenoid esters. Besides the methodology's insufficient description, the lack of use of more accurate techniques and practices led to a high risk of bias in the carotenoid assignment in 17.65% of the articles. This review highlights the opportunity to broaden carotenoid studies to other species and parts within the diverse Passiflora genus, especially to wild, locally available fruits, which may have a strategic role in enhancing food diversity and security amidst climatic changes. Additionally, it urges the use of more accurate and efficient analytical methods based on green chemistry to better identify Passiflora carotenoids.

Plastid terminal oxidase is required for chloroplast biogenesis in barley

Chloroplast biogenesis is critical for crop biomass and economic yield. However, chloroplast development is a very complicated process coordinated by cross-communication between the nucleus and plastids, and the underlying mechanisms have not been fully revealed. To explore the regulatory machinery for chloroplast biogenesis, we conducted map-based cloning of the Grandpa 1 (Gpa1) gene regulating chloroplast development in barley. The spontaneous mutation gpa1.a caused a variegation phenotype of the leaf, dwarfed growth, reduced grain yield, and increased tiller number. Genetic mapping anchored the Gpa1 gene onto 2H within a gene cluster functionally related to photosynthesis or chloroplast differentiation. One gene (HORVU.MOREX.r3.2HG0213170) in the delimited region encodes a putative plastid terminal oxidase (PTOX) in thylakoid membranes, which is homologous to IMMUTANS (IM) of Arabidopsis. The IM gene is required for chloroplast biogenesis and maintenance of functional thylakoids in Arabidopsis. Using CRISPR technology and gene transformation, we functionally validated that the PTOX-encoding gene, HORVU.MOREX.r3.2HG0213170, is the causal gene of Gpa1. Gene expression and chemical analysis revealed that the carotenoid biosynthesis pathway is suppressed by the gpa1 mutation, rendering mutants vulnerable to photobleaching. Our results showed that the overtillering associated with the gpa1 mutation was caused by the lower accumulation of carotenoid-derived strigolactones (SLs) in the mutant. The cloning of Gpa1 not only improves our understanding of the molecular mechanisms underlying chloroplast biosynthesis but also indicates that the PTOX activity is conserved between monocots and dicots for the establishment of the photosynthesis factory.

Beneficial effect of ζ-carotene-like compounds on acute UVB irradiation by alleviating inflammation and regulating intestinal flora

ζ-Carotene is a key intermediate in the carotenoid pathway, but owing to its low content and difficulties in isolation, its application is restricted. In this study, three genes (pnCrtE, pnCrtB, and pnCrtP) in the carotenoid pathway of Antarctic moss were identified, recombined, and expressed in Escherichia coli (E. coli) BL21(DE3). The expression product was identified as one of the ζ-carotenes by UV absorbance spectrum, thin layer chromatography (TLC), and super-high-performance liquid chromatography-mass spectrum (UPLC-MS), and was called a ζ-carotene-like compound (CLC). Excessive exposure to ultraviolet B (UVB) irradiation is one of the main risk factors for skin photodamage. The purpose of this study was to investigate the preventive and therapeutic effects of CLC on UVB-induced skin photodamage in mice. In this paper, through histological examinations (hematoxylin-eosin, HE; Masson and TdT-mediated dUTP Nick-End Labeling, Tunel), biochemical index detection (reactive oxygen species, ROS; inflammatory factors; cyclobutyl pyrimidine dimers, CPDs and hyaluronic acid, HA), quantitative real time polymerase chain reaction (qRT-PCR), immunohistochemistry and intestinal content flora, etc., it is concluded that CLC has the potential to enhance skin antioxidant capacity by activating the nuclear transcription factor/antioxidant reaction element (Nrf2/ARE) pathway and also reduce skin inflammation and aging by inhibiting the mitogen-activated protein kinase (MAPK) pathway. Moreover, the regulation of intestinal flora may potentially mitigate skin damage induced by UVB radiation. This research not only developed a green and sustainable platform for the efficient synthesis of CLC but also laid a foundation for its application in functional food and medicine for skin resistance against UVB damage.

Extraction and characterisation of pigment from Yanzhiguo [Prunus napaulensis (Ser.) Steud.]

Yanzhiguo [Prunus napaulensis (Ser.) Steud] belongs to Rosaceae family and is consumed as wild fruit, pulp and juice. However, its potential for extracting natural pigment has not yet been explored. Herein, the components in the fresh Yanzhiguo pulp were preliminarily analyzed by liquid chromatography coupled to mass spectrometry. And, the optimal pre-treatment conditions were established for further extraction of Yanzhiguo pigment based on the a* value. Then, by combining the data from single-factor experiments and response surface methodology, the optimal extraction process was established as: 35% EtOH, a liquid-solid ratio of 200:1 mL g-1, an extraction time of 65 min, and an extraction temperature of 100 °C. Moreover, it was found that the a* value and yield had high fitness except when extracted into ethanol (EtOH) with different concentrations. Meanwhile, our result demonstrated Yanzhiguo pigment had high stability in general environments with carmine (a synthetic pigment) as control, except for extreme environments such as direct (hot) sunlight, high temperature (75 °C) and strong alkaline (pH ≥ 11). Also, Yanzhiguo pigment exhibited good antioxidant activity. Our results contribute to more information on Yanzhiguo pigment and promote its application by providing efficient extraction technology.

Carotenoid Differences and Genetic Diversity in Populations of Sargassum hemiphyllum and Sargassum fusiforme

Sargassum hemiphyllum and Sargassum fusiforme are important benthic seaweeds that grow along the southeastern coast of China. The content of carotenoids in each population was detected by ultra-high performance liquid chromatography (UHPLC). The research results will enrich the theoretical basis and data support concerning the influencing factors of carotenoids in Sargassum. The inter-simple sequence repeat (ISSR) technique was used to study the genetic diversity of four S. hemiphyllum and two S. fusiforme populations, and the results provide a reference for the artificial cultivation of Sargassum. The total carotenoid content of Sargassum ranged from 161.79 ± 4.22 to 269.47 ± 6.15 μg/g. Among the carotenoids, β-carotene and fucoxanthin accounted for 80%, and levels in S. hemiphyllum were generally higher than those in S. fusiforme. The carotenoid contents of S. hemiphyllum from different areas were significantly different (P < 0.05), and the total carotenoids content decreased toward the southern region. The average heterozygosity H ranged from 0.29 to 0.49, and the Shannon diversity index I ranged from 0.44 to 0.69. The polymorphic loci, genetic diversity, and other indicators of S. hemiphyllum populations were higher than those of S. fusiforme, and the diversity of cultivated populations was not significantly lower. The results showed that the genetic variation of Sargassum is limited, and thus, more sexual reproduction can be attempted in breeding. Considering morphological indicators, genetic diversity indexes, and carotenoid content, S. hemiphyllum appears to have a higher commercial development value.

Multivitamin/Multimineral Supplementation Prevents or Reverses Decline in Vitamin Biomarkers and Cellular Energy Metabolism in Healthy Older Men: A Randomized, Double-Blind, Placebo-Controlled Study

Despite the reported prevalence of micronutrient deficiencies in older adults, it is not yet established whether multivitamin/multimineral (MV/MM) supplements improve blood micronutrient status in individuals over the age of 65. Therefore, a cohort of 35 healthy men (>67 years) was recruited for an MV/MM supplementation trial. The primary endpoint was, as an indicator of micronutrient status, changes in blood micronutrient biomarkers from baseline to at least six months of supplementation with MV/MM or placebo. The secondary endpoint was basal O2 consumption in monocytes as an indicator of cellular metabolism. MV/MM supplementation improved blood concentrations of pyridoxal phosphate, calcifediol, α-tocopherol, and β-carotene concentrations throughout the cohort. By contrast, those in the placebo group generally showed declines in blood vitamin concentrations and an increased prevalence of suboptimal vitamin status during the study period. On the other hand, MV/MM supplementation did not significantly affect blood mineral concentrations, i.e., calcium, copper, iron, magnesium, and zinc. Interestingly, MV/MM supplementation prevented the decline in monocyte O2 consumption rate. Overall, MV/MM use improves or prevents declines in vitamin, but not mineral, status and limits declines in cellular O2 consumption, which may have important implications for metabolism and immune health in healthy older men.

Development of a screening method for the determination of carotenoids in ham sausage, juice, and cookies by an improved Bligh-Dyer method and LC-MS/MS

A screening method of 23 carotenoids in foods, such as ham sausage, juice, and cookies, was proposed using an improved Bligh-Dyer method that can satisfy the extraction requirements of common carotenoids with different physicochemical properties, including free and esterified carotenoids, by collecting the aqueous and organic phases simultaneously. Purification was then performed by loading the aqueous phase onto a hydrophile-lipophile balance (HLB) column; a methanol-water solution was used for washing, and the organic phases and additional chloroform were used for elution. By optimizing this step, interference from hydrophilic compounds and neutral triglycerides was effectively eliminated, and the matrix suppression effect after purification was greater than -16.3%. Finally, the extract was analyzed by ultrahigh performance liquid chromatography-quadrupole-orbitrap high-resolution mass spectrometry. The results showed that the 23 carotenoids showed a good linear relationship in the range of 0.01-0.2 µg/mL, and the limits of quantification (signal-to-noise ratio ≥10) were from 0.02 to 0.05 mg/kg. The average recoveries were 80.1%-98.7%, with relative standard deviation ≤10%. The proposed method can simultaneously identify and quantify 23 carotenoids in foods with high throughput, sensitivity, and reliability.

Recent progress in emulsion gels: from fundamentals to applications

Emulsion gels, also known as gelled emulsions or emulgels, have garnered great attention both in fundamental research and practical applications due to their superior stability, tunable morphology and microstructure, and promising mechanical and functional properties. From an application perspective, attention in this area has been, historically, mainly focused on food industries, e.g., engineering emulsion gels as fat substitutes or delivery systems for bioactive food ingredients. However, a growing body of studies has, in recent years, begun to demonstrate the full potential of emulsion gels as soft templates for designing advanced functional materials widely applied in a variety of fields, spanning chemical engineering, pharmaceutics, and materials science. Herein, a concise and comprehensive overview of emulsion gels is presented, from fundamentals to applications, highlighting significant recent progress and open questions, to scout for and deepen their potential applications in more fields.

Ramie leaf Extract Alleviates Bone Loss in Ovariectomized Rats-The Involvement of ROS and Its Associated Signalings

Ramie leaf (Boehmeria nivea L.) has been traditionally used to treat gynecological and bone-related disorders. This study aims to evaluate the effect of Ramie leaf extracts (RLE) against osteoporosis in ovariectomized (OVX) rats. Female SD rats aged seven weeks were randomly assigned into five OVX and a sham-operated (sham) group. OVX subgroups include OVX, vehicle-treated OVX group; E2, OVX with 100 μg/kg 17β-estradiol; and RLE 0.25, 0.5, and 1, OVX rats treated with 0.25, 0.5, and 1 g/kg/day RLE, respectively. Two weeks into the bilateral ovariectomy, all the rats were orally administered with or without RLE daily for 12 weeks. OVX rats administered with RLE showed higher bone density, relatively low tartrate-resistant acid phosphatase (TRAP)-positive osteoclasts, and lower reactive oxygen species (ROS) within bone tissues compared to vehicle-treated OVX rats. Furthermore, supplementation of RLE improved bone mineral density (BMD) and bone microstructure in the total femur. RLE prevented RANKL-induced osteoclast differentiation and expression of osteoclastogenesis-related genes such as Cal-R, MMP-9, cathepsin K, and TRAP in RANKL-induced RAW264.7 cells. Moreover, RLE administration lowered the intracellular ROS levels by reducing NADPH oxidase 1 (NOX-1) and 4-hydroxynonenal (4HNE). These results suggest that RLE alleviates bone mass loss in the OVX rats by inhibiting osteoclastogenesis, where reduced ROS and its associated signalings were involved.

Advances in the synthesis of three typical tetraterpenoids including β-carotene, lycopene and astaxanthin

Carotenoids are natural pigments that widely exist in nature. Due to their excellent antioxidant, anticancer and anti-inflammatory properties, carotenoids are commonly used in food, medicine, cosmetic and other fields. At present, natural carotenoids are mainly extracted from plants, algae and microorganisms. With the rapid development of metabolic engineering and molecular biology as well as the continuous in-depth study of carotenoids synthesis pathways, industrial microorganisms have showed promising applications in the synthesis of carotenoids. In this review, we introduced the properties of several carotenoids and their biosynthetic metabolism process. Then, the microorganisms synthesizing carotenoids through the natural and non-natural pathways and the extraction methods of carotenoids were summarized and compared. Meanwhile, the influence of substrates on the carotenoids production was also listed. The methods and strategies for achieving high carotenoid production are categorized to help with future research.

Enhancement of violaxanthin accumulation in Nannochloropsis oceanica by overexpressing a carotenoid isomerase gene from Phaeodactylum tricornutum

Nannochloropsis has been considered as a promising feedstock for the industrial production of violaxanthin. However, a rational breeding strategy for the enhancement of violaxanthin content in this microalga is still vacant, thereby limiting its industrial application. All-trans-lycopene locates in the first branch point of carotenogenesis. The carotenoid isomerase (CRTISO), catalyzing the lycopene formation, is thus regarded as a key enzyme for carotenogenesis. Phaeodactylum tricornutum can accumulate high-level carotenoids under optimal conditions. Therefore, it is feasible to improve violaxanthin level in Nannochloropsis by overexpression of PtCRTISO. Protein targeting analysis of seven PtCRTISO candidates (PtCRTISO1–6 and PtCRTISO-like) demonstrated that PtCRTISO4 was most likely the carotenoid isomerase of P. tricornutum. Moreover, the transcriptional pattern of PtCRTISO4 at different cultivation periods was quite similar to other known carotenogenesis genes. Thus, PtCRTISO4 was transformed into N. oceanica. Compared to the wild type (WT), all three transgenic lines (T1–T3) of N. oceanica exhibited higher levels of total carotenoid and violaxanthin. Notably, T3 exhibited the peak violaxanthin content of 4.48 mg g^–1 dry cell weight (DCW), which was 1.68-folds higher than WT. Interestingly, qRT-polymerase chain reaction (PCR) results demonstrated that phytoene synthase (NoPSY) rather than ζ-carotene desaturase (NoZDS) and lycopene β-cyclase (NoLCYB) exhibited the highest upregulation, suggesting that PtCRTISO4 played an additional regulatory role in terms of carotenoid accumulation. Moreover, PtCRTISO4 overexpression increased C18:1n-9 but decreased C16:1n-7, implying that C18:1 may serve as a main feedstock for xanthophyll esterification in Nannochloropsis. Our results will provide valuable information for the violaxanthin production from Nannochloropsis.