Identification of phenolic compounds in petals of nasturtium flowers (Tropaeolum majus) by high-performance liquid chromatography coupled to mass spectrometry and determination of oxygen radical absorbance capacity (ORAC)

Natural biosynthesis, pharmacological applications, and sustainable biotechnological production of ornamental plant-derived anthocyanin: beyond colorants and aesthetics

Flowers have long been admired for their aesthetic qualities and have even found their way to be included in the human diet. Among the many chemical compounds found in flowers, anthocyanins stand out for their versatile applications in the food, cosmetic, and nutraceutical industries. The biosynthetic pathway of anthocyanins has been thoroughly studied in certain flower species, leading to the detection of key regulatory genes that can be controlled to enhance the production of anthocyanins via biotechnological methods. Nevertheless, the quantity and form of anthocyanins found in natural sources differ, both qualitatively and quantitatively, depending on the ornamental plant species. For this reason, research on in vitro plant cultures has been conducted for years in an attempt to comprehend how these essential substances are produced. Different biotechnological systems, like in vitro plant cell, organ, and tissue cultures, and transgenic approaches, have been employed to produce anthocyanins under controlled conditions. However, multiple factors influence the production of anthocyanins and create challenges during large-scale production. Metabolic engineering techniques have also been utilized for anthocyanin production in microorganisms and recombinant plants. Although these techniques are primarily tested at lab- and pilot-scale, limited studies have focused on scaling up the production. This review analyses the chemistry and biosynthesis of anthocyanin along with the factors that influence the biosynthetic pathway. Further emphasis has been given on strategies for conventional and non-conventional anthocyanin production along with their quantification, addressing the prevailing challenges, and exploring ways to ameliorate the production using the in vitro plant cell and tissue culture systems and metabolic engineering to open up new possibilities for the cosmetic, pharmaceutical, and food industries.

Tropaeolum majus L. and low dose gamma radiation suppress liver carcinoma development via EGFR-HER2 signaling pathway

Hepatocellular carcinoma (HCC) is one of the most fatal cancers around the world and remain asymptomatic in early stage. An alcoholic extract prepared from leaves of Tropaeolum majus L. (Tropaeolaceae) was assessed for its potential activity against diethylnitrosamine-induced liver carcinoma in vivo. Oral administration of the extract significantly decreased the inflammatory marker translation NF-kB and supressed HCC progression in combination with 0.5 Gy gamma radiation via EGF-HER-2 pathway. Histopathological and immunohistopathological features also showed the recovery of a hepatic architecture. Immunohistochemical study showed the T. majus and LDR enhancement effect on proapoptotic markers (caspase-3 and Bax) and inhibition of anti-apoptotic factor (BCl2). HPLC-DAD-MSⁿ analysis of the extract revealed the annotation of twelve compounds. T. majus could mediate a defensive influence against diethylnitrosamine-induced hepatocarcinogenesis and serve as a respectable option in amelioration of the hepatocellular carcinoma development in combination with low dose of gamma radiation.

Centranthus ruber (L.) DC. and Tropaeolum majus L.: Phytochemical Profile, In Vitro Anti-Denaturation Effects and Lipase Inhibitory Activity of Two Ornamental Plants Traditionally Used as Herbal Remedies

Ornamental plants often gain relevance not only for their decorative use, but also as a source of phytochemicals with interesting healing properties. Herein, spontaneous Centranthus ruber (L.) DC. and Tropaeolum majus L., mainly used as ornamental species but also traditionally consumed and used in popular medicine, were investigated. The aerial parts were extracted with methanol trough maceration, and resultant crude extracts were partitioned using solvents with increasing polarity. As previous studies mostly dealt with the phenolic content of these species, the phytochemical investigation mainly focused on nonpolar constituents, detected with GC-MS. The total phenolic and flavonoid content was also verified, and HPTLC analyses were performed. In order to explore the potential antiarthritic and anti-obesity properties, extracts and their fractions were evaluated for their anti-denaturation effects, with the use of the BSA assay, and for their ability to inhibit pancreatic lipase. The antioxidant properties and the inhibitory activity on the NO production were verified, as well. Almost all the extracts and fractions demonstrated good inhibitory effects on NO production. The n-hexane and dichloromethane fractions from T. majus, as well as the n-hexane fraction from C. ruber, were effective in protecting the protein from heat-induced denaturation (IC₅₀ = 154.0 ± 1.9, 270.8 ± 2.3 and 450.1 ± 15.5 μg/mL, respectively). The dichloromethane fractions from both raw extracts were also effective in inhibiting pancreatic lipase, with IC₅₀ values equal to 2.23 ± 0.02 mg/mL (for C. ruber sample), and 2.05 ± 0.02 mg/mL (T. majus). Obtained results support the traditional use of these species for their beneficial health properties and suggest that investigated plant species could be potential sources of novel antiarthritic and anti-obesity agents.

Tropaeolum majus R2R3 MYB Transcription Factor TmPAP2 Functions as a Positive Regulator of Anthocyanin Biosynthesis

Anthocyanins are an important group of water-soluble and non-toxic natural pigments with antioxidant and anti-inflammatory properties that can be found in flowers, vegetables, and fruits. Anthocyanin biosynthesis is regulated by several different types of transcription factors, including the WD40-repeat protein Transparent Testa Glabra 1 (TTG1), the bHLH transcription factor Transparent Testa 8 (TT8), Glabra3 (GL3), Enhancer of GL3 (EGL3), and the R2R3 MYB transcription factor Production of Anthocyanin Pigment 1 (PAP1), PAP2, MYB113, and MYB114, which are able to form MYB-bHLH-WD40 (MBW) complexes to regulate the expression of late biosynthesis genes (LBGs) in the anthocyanin biosynthesis pathway. Nasturtium (Tropaeolum majus) is an edible flower plant that offers many health benefits, as it contains numerous medicinally important ingredients, including anthocyanins. By a comparative examination of the possible anthocyanin biosynthesis regulator genes in nasturtium varieties with different anthocyanin contents, we found that TmPAP2, an R2R3 MYB transcription factor gene, is highly expressed in “Empress of India”, a nasturtium variety with high anthocyanin content, while the expression of TmPAP2 in Arabidopsis led to the overproduction of anthocyanins. Protoplast transfection shows that TmPAP2 functions as a transcription activator; consistent with this finding, some of the biosynthesis genes in the general phenylpropanoid pathway and anthocyanin biosynthesis pathway were highly expressed in “Empress of India” and the 35S:TmPAP2 transgenic Arabidopsis plants. However, protoplast transfection indicates that TmPAP2 may not be able to form an MBW complex with TmGL3 and TmTTG1. These results suggest that TmPAP2 may function alone as a key regulator of anthocyanin biosynthesis in nasturtiums.

Bioactive profile of edible nasturtium and rose flowers during simulated gastrointestinal digestion

Rose and nasturtium are common ornamental edible flowers rich in phytochemicals whose application as food is not widely explored. The gastrointestinal environment can modify these compounds, resulting in new combinations with different bioactivity. This study aimed to evaluate the effects of simulated gastrointestinal digestion (SGD) on rose and nasturtium flower extracts. Using UPLC-HRMS, 38 phenolic compounds were identified, and the SGD caused significant changes, mainly in the glycosylated phenolic. Furthermore, antioxidant activity was correlated with the increase in the concentrations of some polyphenols. Tested Gram-negative bacteria showed sensitivity to the flower extracts; their growth was inhibited by up to 82.7%. SGD interrupted the bacterial growth inhibition power of the rose extracts. On the other hand, an increase in inhibition ranging from 52.25 to 54.72%was found for nasturtium extracts, correlated to the behavior of some bioactive. Hence, SGD resulted in significant changes in phenolic profiles of the edible flowers, increasing antioxidant activity and changing antimicrobial effects.

Application of Optical Fluorescence Spectroscopy for Studying Bee Abundance in Tropaeolum majus L. (Tropaeolaceae)

Tropaeolum majus L. species produce flowers with all sorts of colors, from yellow to red. This work aimed to apply optical fluorescence spectroscopy to study bee abundance in T. majus, answering the following questions: (1) do corolla temperature and weather conditions affect the abundance of visiting bee species? (2) do flower color and corolla fluorescence affect the abundance of visiting bee species? (3) do red flowers attract more visiting bees? (4) is there a relationship between bee visits and flower compounds? The bee species Apis mellifera, Paratrigona lineata, and Trigona spinipes were the most observed in T. majus flowers. The latter was more active in the morning and preferred orange and yellow flowers. These colors also had higher temperatures and fluorescence emissions than did the red ones and those with yellow-red and orange-red nectar guides. Orange flowers emitted a broadband UV spectrum (between 475 and 800 nm). This range might be due to compounds such as hydroxycinnamic acid, flavonols, isoflavonoids, flavones, phenolic acid, and chlorophyll. Extracts from different T. majus corolla colors showed that flowers emit specific fluorescent signals, mainly related to bee color vision and learning, thus acting as a means of communication between bees and flowers. In this way, this information evidences the interaction between bees and T. majus flowers, allowing conservation actions for pollinators.

High throughput analytical approach based on μQuEChERS combined with UHPLC-PDA for analysis of bioactive secondary metabolites in edible flowers

Mallow blue (Malva sylvestris L.), hibiscus (Hibiscus rosa-sinensis L.) and nasturtium (Tropaeolum majus L.), are common edible flowers rich in bioactive secondary metabolites (BASMs) whose use in sophisticated gastronomy present currently as increasing trend. In this study the BASMs profile of these edible flowers was established using an emerging green extraction technique, μQuEChERS followed by ultra-high performance liquid chromatography coupled to a photodiode array detection system (UHPLC-PDA). After validation the μQuEChERS/UHPLC-PDA methodology allow to identify that apigenin and epigallocatechin gallate are the most abundant BASMs in mallow blue flowers, while catechin and dicaffeoylquinic acid are predominant in hibiscus flowers, and myricitrin and dicaffeoylquinic acid in nasturtium flowers. Total polyphenol content is the highest in the extract of hibiscus. Nasturtium shows the greatest radical scavenging activity. The results revealed that these flowers constitute a potential source of BASMs with different bioactive properties suggesting its use in design of new functional foods.

Phenolic Composition and Antioxidant Properties of 2 Taxa of Macadamia Flowers

This study investigated the differences in phenolic composition and antioxidant properties among 4 extracts (eg,70% acetone, 70% methanol, 70% ethanol, and water) of 2 taxa of Macadamia flowers (“Nanya No.2” and “HAES695” cultivars). The results showed that the phenolic compounds and antioxidant properties of the extracts were taxa- and solvent-dependent. “Nanya No.2” flowers possessed remarkably more phenolics and flavonoids, with more robust antioxidant activities than “HAES695”. The 70% acetone extract exhibited the highest polyphenol levels and antioxidant capacities, indicating that 70% acetone would be the most efficient solvent for extracting phenolic antioxidants from macadamia flowers. The high-performance liquid chromatography (HPLC) analysis revealed rutin and catechin as the richest compounds in the extracts of both cultivars. Ferulic acid, catechin, phlorizin, quercetin, and kaempferol positively correlated with the antioxidant properties of the macadamia flowers. These results provide valuable information for utilizing macadamia flowers in antioxidant foods.

Phytochemical Profiling and Isolation of Bioactive Compounds from Leucosidea sericea (Rosaceae)

In the study, ultraperformance liquid chromatography-quadrupole time-of-flight-mass spectrometry analysis of Leucosidea sericea leaf and stem extracts led to the identification of various classes of compounds. Further chromatographic purifications resulted in the isolation of 22 compounds that consisted of a new triterpenoid named leucosidic acid A (1), an acetophenone derivative 2, a phloroglucinol derivative 3, three chromones 4-6, seven pentacyclic triterpenoids 7-13, a phytosterol glucoside 14, a flavonoid 15, and seven flavonoid glycosides 16-22. Nineteen of these compounds including the previously undescribed triterpenoid 1 are isolated for the first time from L. sericea. The structures of the isolated compounds were assigned based on their high-resolution mass spectrometry and nuclear magnetic resonance data. Some of the isolated triterpenoids were evaluated for inhibitory activity against α-amylase, α-glucosidase, and pancreatic lipase. Of the tested compounds, 1-hydroxy-2-oxopomolic acid (7) and pomolic acid (13) showed higher potency on α-glucosidase than acarbose, which is used as a positive control in this study. The two compounds inhibited α-glucosidase with IC₅₀ values of 192.1 ± 13.81 and 85.5 ± 6.87 μM, respectively.

Ornamental Flowers Grown in Human Surroundings as a Source of Anthocyanins with High Anti-Inflammatory Properties

Flowers have always accompanied people thanks to their manifold aesthetic properties. Some species have also become a component of the human diet. Recent years have seen an increased interest in edible flowers and, consequently, research has been undertaken to determine their chemical composition. Dyes that are abundantly contained in flowers, whose role is to attract pollinating animals, are recognized substances with health-promoting properties. Anthocyanins are a group of dyes that are very common in petals and other parts of flowers. Studies carried out in the twentieth and twenty-first century on flowers growing in temperate climates have found very strong antioxidant and anti-inflammatory properties of anthocyanins. Therefore, flowers used by humans for centuries to decorate their surroundings may become an easily available source of nutrients and health-promoting substances. This paper discusses the health-promoting properties of anthocyanins and collects literature on anthocyanin content in edible flowers commonly grown on balconies, terraces, and roofs in countries of temperate climate.

The Compositional Aspects of Edible Flowers as an Emerging Horticultural Product

Edible flowers are becoming very popular, as consumers are seeking healthier and more attractive food products that can improve their diet aesthetics and diversify their dietary sources of micronutrients. The great variety of flowers that can be eaten is also associated with high variability in chemical composition, especially in bioactive compounds content that may significantly contribute to human health. The advanced analytical techniques allowed us to reveal the chemical composition of edible flowers and identify new compounds and effects that were not known until recently. Considering the numerous species of edible flowers, the present review aims to categorize the various species depending on their chemical composition and also to present the main groups of compounds that are usually present in the species that are most commonly used for culinary purposes. Moreover, special attention is given to those species that contain potentially toxic or poisonous compounds as their integration in human diets should be carefully considered. In conclusion, the present review provides useful information regarding the chemical composition and the main groups of chemical compounds that are present in the flowers of the most common species.

Antirrhinum majus L. flower extract inhibits cell growth and metastatic properties in human colon and lung cancer cell lines

Snapdragon ( Antirrhinum majus L.) flowers are one of the most frequently used edible flowers in different preparations of foods and drinks. In this study, we examined inhibitory effects of snapdragon flower extract (SFE) against distinctive properties of cancer cells, stimulated growth, and activated metastasis, using H1299 lung cancer and HCT116 colon cancer cell lines. SFE treatment at 100-1,000 μg/ml for 24-72 hr resulted in a time- and dose-dependent growth inhibition in H1299 and HCT116 cells. Cell cycle analysis and Annexin V staining assay further revealed that SFE caused cell cycle arrest at G2/M phase and induction of apoptosis, indicating the growth inhibition by SFE is attributed to its G2/M cell cycle-arresting and apoptosis-inducing activities. SFE dose-dependently enhanced generation of intracellular reactive oxygen species (ROS) and reduced mitochondrial membrane potential in H1299 cells but had no effect on intracellular ROS levels in HCT116 cells, suggesting that the type of apoptosis induced by SFE in H1299 cells is different to that in HCT116 cells. Furthermore, SFE alleviated invasion, levels of matrix metalloproteinases, migration, and adhesion in H1299 and HCT116 cells. These results indicate that SFE not only inhibits cell growth by cell cycle arrest at G2/M and apoptosis induction but also alleviates metastatic properties such as invasion, migration, and adhesion in lung and colon cancer cells.

Anthocyanins, Vibrant Color Pigments, and Their Role in Skin Cancer Prevention

Until today, numerous studies evaluated the topic of anthocyanins and various types of cancer, regarding the anthocyanins' preventative and inhibitory effects, underlying molecular mechanisms, and such. However, there is no targeted review available regarding the anticarcinogenic effects of dietary anthocyanins on skin cancers. If diagnosed at the early stages, the survival rate of skin cancer is quite high. Nevertheless, the metastatic form has a short prognosis. In fact, the incidence of melanoma skin cancer, the type with high mortality, has increased exponentially over the last 30 years, causing the majority of skin cancer deaths. Malignant melanoma is considered a highly destructive type of skin cancer due to its particular capacity to grow and spread faster than any other type of cancers. Plants, in general, have been used in disease treatment for a long time, and medicinal plants are commonly a part of anticancer drugs on the market. Accordingly, this work primarily aims to emphasize the most recent improvements on the anticarcinogenic effects of anthocyanins from different plant sources, with an in-depth emphasis on melanoma skin cancer. We also briefly summarized the anthocyanin chemistry, their rich dietary sources in flowers, fruits, and vegetables, as well as their associated potential health benefits. Additionally, the importance of anthocyanins in topical applications such as their use in cosmetics is also given.

Effect of modified atmosphere packaging on overall appearance and nutraceutical quality of pot marigold held at 5 °C

The effectiveness of passive modified atmosphere packaging (MAP) on chemical and quality properties of calendula flowers was studied during ten days of storage at 5 °C. Weight loss of flowers wrapped with continuous and micro-perforated-films (2-3%), was significantly lower than control (unwrapped flowers) (about 30%) and those wrapped with macro-perforated film (about 7%). At the end of storage unwrapped flowers were judged unmarketable being severely wilted and shriveled, while all packaged ones were still fresh and marketable. On day 10, the fructose concentration of control flowers decreased by 74%. Continuous and micro-perforated films delayed the decline of fructose concentration over storage. Sucrose concentration decreased with storage in control flowers, while in continuous film wrapped flowers it increased. After 10 d of storage, the total phenols' concentration of all packaged flowers was significantly higher than control and similar to the initial value (2.58 ± 0.02 g 100 g^-1 d.w.). Thirteen carotenoids were identified by HPLC-MS. The initial β carotene concentration (65.72 ± 0.09 mg 100 g^-1 d.w.) did not change in flowers wrapped with macro- and micro-perforated films, in contrast to the other treatments. Lycopene concentration strongly decreased in control flowers, while minor losses occurred in packaged ones. Laser micro-perforated film, being a good compromise between humidity retention inside the packages and the permeability of the film, seems to be the best choice to extend the storage life of calendula flowers.

Phytochemicals screening, antioxidant capacity and chemometric characterization of four edible flowers from Brazil

Edible flowers are receiving renewed interest as potential sources of bioactive compounds. The present study aimed to investigate the presence of bioactive compounds and antioxidant activity of some exotic flowers present in Brazil such as Amaranthus hypochondriacus, Tropaeolum majus (red), Tropaeolum majus (orange) and Spilanthes oleracea L. The content of total phenolic compounds, flavonoids, condensed, hydrolysable tannins and antioxidante capacity were determined. The identification and quantification of the phenolic compounds was performed through the UHPLC-QDa-MS system. The compounds p-coumaric acid and ferulic acid were identified and quantified for the first time in all flowers. Tropaeolum majus (red) presented the hightest amounts of total phenolic compounds and hydrolysable tannins. Also, it presented the highest antioxidant capacity for ORAC and FRAP assays. Thus, this study showed the diversity and abudance of natural antioxidants present in edible flowers, which could be explored for application in functional foods and pharmaceuticals.

Anti-Hyperglycemic and Anticholinergic Effects of Natural Antioxidant Contents in Edible Flowers

In this study, 16 selected edible flowers were evaluated for their content of bioactive compounds (polyphenols, carotenoids, triterpenoids) and for their anti-diabetic (ability to inhibit α-amylase and α-glucosidases) and anti-aging (ability to inhibit acetylcholinesterase and butyrylcholinesterase) activities. Most of the flowers analyzed in this study have not been examined in this respect until now. Contents of the analyzed bioactive compounds differed significantly among the flowers. In particular, the highest contents of carotenoids and triterpenoids were determined in marigold, arnica, lavender, and daisy; in turn, the highest contents of phenolic acids, procyanidin polymers, and total polyphenols were assayed in hawthorn, primrose, and linden blossom. There was a positive correlation between the content of isoprenoids in edible flowers and their anti-aging activity, and between the content of polymeric procyanidins and flowers' ability to inhibit α-glucosidase. In conclusion, edible flowers may be used to produce functional foods as well as for medical purposes.

Effects of elevated CO2 concentration on leaves and berries of black elder (Sambucus nigra) using UHPLC-ESI-QTOF-MS/MS and gas exchange measurements

The effect of elevated CO₂ concentration on leaves of black elder (Sambucus nigra) was investigated based on leaf gas exchange, chlorophyll content as well as on the analysis of the underlying metabolite profile of the fruits. The measurements were carried out once a month over a period of time of 4 months. The CO₂ uptake rate, the transpiration rate and stomatal conductance were significantly higher in plants under ambient CO₂, in comparison to plants grown under elevated CO₂ concentrations. On the other hand, at the initial phase of the experiments, the photosynthesis rate was higher in CO₂ loaded plants compared to plants grown under normal conditions. Remarkably, after about one month a habituation effect could be observed leading to a decrease of the photosynthetic efficiency approaching again the normal level. To understand the observed effects on a molecular level, non-targeted fingerprinting analysis was performed on the ripe elder berries using LC-qToF-ESI-MS(/MS). Differences in the composition of various phenols, triglycerides and PC (36:5) as well as a stigmasterole-derivate could be detected. In contrast, central metabolic pathways such as photosynthesis, the tricarboxylic acid cycle as well as the biosynthesis of essential amino acids obviously are not considerably affected.

Extraction of antioxidant and antiproliferative ingredients from fruits of Rubus chingii Hu by active tracking guidance

Rubus chingii Hu, namely "Fu-pen-zi" in Chinese, has been used as a functional food in China for a long time. This study aims to identify its bioactive constituents with antioxidant and anti-tumor properties. R. chingii was extracted with 95% ethanol and then partitioned into four fractions: petroleum ether fraction, ethyl acetate fraction, n-butanol fraction, and water fraction. Results showed that the ethyl acetate fraction had the strongest antioxidant activity and cytotoxicity against human cancer cell lines (HepG-2, Bel-7402, A549 and MCF-7). Therefore, four compounds were isolated from the ethyl acetate fraction, and they were identified as ent-16α,17-dihydroxy-kauran-19-oic acid, tormentic acid, oleanolic acid and β-daucosterol, the first two of which were isolated and identified from R. chingii for the first time. In particular, tormentic acid exhibited excellent cytotoxicity activities against human tumor cell lines. The results obtained in this work might contribute to the understanding of biological activities of R. chingii and further investigation on its potential application is valued for food and drugs.

Antioxidant activity of whole grain highland hull-less barley and its effect on liver protein expression profiles in rats fed with high-fat diets

PURPOSE

Whole grain exhibits potential for regulating lipid levels, possibly because of its antioxidant activity. This study aims to investigate the antioxidant activity of whole grain highland hull-less barley (WHLB) and its effect on liver protein expression profiles in rats fed with high-fat diets.

METHODS

Antioxidant activity of WHLB was investigated in vitro by analyzing phenolic and pentosan contents and oxygen radical absorbance capacity (ORAC). Proteins involved in lipid regulation were investigated in vivo by analyzing liver protein expression profiles in Sprague-Dawley rats fed with high-fat diet (HFD) with or without WHLB.

RESULTS

WHLB possessed high total phenolic content (259.90 mg/100 g), total pentosan content (10.74 g/100 g), and ORAC values (418.05 ± 5.65 μmol/g). Rats fed with WHLB diet exhibited significantly (P < 0.05) lower liver lipid levels than those fed with the control HFD diet. Seven differentially expressed proteins were detected through liver proteome analysis and were found to be correlated with 11 pathways, including lipid metabolism, through annotation with Kyoto Encyclopedia of Genes and Genomes. Quantitative real-time polymerase chain reaction analysis showed that rats given with WHLB diet exhibited down-regulated expression of heat shock protein 60 (HSP60) and phosphatidylethanolamine binding protein 1 (PEBP1) and up-regulated expression of enoyl-coenzyme A hydratase (ECH) and peroxiredoxin 6 (PRDX6).

CONCLUSIONS

HSP60, PEBP1, ECH, and PRDX6 may be involved in the lipid regulatory effect of WHLB. Moreover, the regulation of PRDX6 may be related to the antioxidant activity of WHLB.