Phenolic compounds, antioxidant potential and antiproliferative potential of 10 common edible flowers from China assessed using a simulated in vitro digestion-dialysis process combined with cellular assays

Phytochemical Analysis, Biological Activities, and Molecular Docking Studies of Root Extracts from Paeonia Species in Serbia

Without being aware of their chemical composition, many cultures have used herbaceous peony roots for medicinal purposes. Modern phytopreparations intended for use in human therapy require specific knowledge about the chemistry of peony roots and their biological activities. In this study, ethanol-water extracts were prepared by maceration and microwave- and ultrasound-assisted extractions (MAE and UAE, respectively) in order to obtain bioactive molecules from the roots of Paeonia tenuifolia L., Paeonia peregrina Mill., and Paeonia officinalis L. wild growing in Serbia. Chemical characterization; polyphenol and flavonoid content; antioxidant, multianti-enzymatic, and antibacterial activities of extracts; and in vitro gastrointestinal digestion (GID) of hot water extracts were performed. The strongest anti-cholinesterase activity was observed in PT extracts. The highest anti-ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical potential was observed in PP extracts, whereas against DPPH (2,2-diphenyl-1-picrylhydrazyl radicals), the best results were achieved with PO extracts. Regarding antibacterial activity, extracts were strongly potent against Bacillus cereus. A molecular docking simulation was conducted to gather insights into the binding affinity and interactions of polyphenols and other Paeonia-specific molecules in the active sites of tested enzymes. In vitro GID of Paeonia teas showed a different recovery and behavior of the individual bioactives, with an increased recovery of methyl gallate and digallate and a decreased recovery of paeoniflorin and its derivatives. PT (Gulenovci) and PP (Pirot) extracts obtained by UAE and M were more efficient in the majority of the bioactivity assays. This study represents an initial step toward the possible application of Paeonia root extracts in pharmacy, medicine, and food technologies.

Cooking methods determine chemical composition and functional properties of squash blossoms: A study of microstructural and bioaccessibility changes

This research aimed to evaluate the effect of different cooking methods (boiling, stir-frying, and steaming) on the microstructure, moisture, fat, protein, and glucose-derived carbohydrate contents, and the bioactive compounds (total carotenoids: CAR, total chlorophyll: CHLO, and total phenolic compounds: TPC) and antioxidant capacity (AC) of squash blossoms. Furthermore, we characterized polyphenolic compounds using HPLC and evaluated their bioaccessibility via in vitro digestions. Our results show that steaming and boiling do not affect moisture content. Only stir-frying decreased (p < 0.05) this parameter by 8 %. Additionally, the cooking methods increased (p < 0.05) protein and glucose-derived carbohydrate contents. All cooking methods changed the microstructure of the blossoms, probably due to the thermal and mechanical variations that result in moisture loss and degradation of cell wall components. As for the functional properties, boiling caused a greater loss of TPC (up to 96 %) and AC (up to 91 %). Stir-frying caused the greatest loss of CAR (up to 81 %) and CHLO (up to 84 %). The in vitro digestion assays showed changes in the bioaccessibility of CAR, CHLO, TPC, and AC in the cooked flowers compared to the fresh ones. Finally, kaempferol and gallic acid were the most resistant polyphenols to the cooking methods and in vitro digestion.

Glycolipid-enriched fraction of Osmanthus fragrans inhibits LPS-induced expression of inflammatory genes, COX-2, E-selectin, and Interleukin-8

ETHNOPHARMACOLOGICAL RELEVANCE

Osmanthus fragrans Lour. is a small ornamental tree native to the Southeastern parts of China. It is mainly cultivated because of its characteristic fragrance, and used in the food and perfume industry. Besides, its flowers are used in traditional Chinese medicine to treat a variety of diseases including those related to inflammation.

AIM OF THE STUDY

The aim of the study was to investigate in more detail the anti-inflammatory properties of O. fragrans flowers, and to characterize their active principles and mechanisms of action.

MATERIALS AND METHODS

O. fragrans flowers were successively extracted with n-hexane, dichloromethane and methanol. The extracts were further fractionated by chromatographic separation. COX-2 mRNA expression in PMA-differentiated, LPS-stimulated THP-1 cells was used as lead assay for activity-guided fractionation. The most potent fraction was chemically analyzed by LC-HRMS. The pharmacological activity was also evaluated in other inflammation-related in-vitro models, such as analysis of IL-8 secretion and E-selectin expression in HUVECtert cells and selective inhibition of COX-isoenzymes.

RESULTS

n-Hexane and dichloromethane extracts of O. fragrans flowers significantly inhibited COX-2 (PTGS2) mRNA expression. Additionally, both extracts inhibited COX-2 enzyme activity, whereas COX-1 enzyme activity was affected to a significantly lower extent. Fractionation of the extracts led to a highly active, glycolipid-containing fraction. In total, 10 glycolipids were tentatively annotated by LC-HRMS. This fraction also inhibited LPS-induced COX-2 mRNA expression, IL-8 secretion and E-selectin expression. The effects were limited to LPS-induced inflammation and not observed when inflammatory genes were induced by TNF-α, IL-1β or FSL-1. Since all these inducers of inflammation act via different receptors, it is likely that the fraction interferes with the binding of LPS to the TLR4-receptor, which mediates pro-inflammatory effects of LPS.

CONCLUSION

Taken together, the results demonstrate the anti-inflammatory potential of O. fragrans flower extracts in general, and of the glycolipid-enriched fraction in particular. The effects of glycolipid-enriched fraction are potentially mediated via the inhibition of the TLR4 receptor complex.

Therapeutic effects of traditional Chinese medicine on gouty nephropathy: Based on NF-κB signalingpathways

As the final product of purine metabolism, excess serum uric acid (SUA) aggravates the process of some metabolic diseases. SUA causes renal tubule damage, interstitial fibrosis, and glomerular hardening, leading to gouty nephropathy (GN). A growing number of investigations have shown that NF-κB mediated inflammation and oxidative stress have been directly involved in the pathogenesis of GN. Traditional Chinese medicine's treatment methods of GN have amassed a wealth of treatment experience. In this review, we first describe the mechanism of NF-κB signaling pathways in GN. Subsequently, we highlight traditional Chinese medicine that can treat GN through NF-κB pathways. Finally, commenting on promising candidate targets of herbal medicine for GN treatment via suppressing NF-κB signaling pathways was summarized.

Widely targeted metabolomics reveals stamen petaloid tissue of Paeonia lactiflora Pall. being a potential pharmacological resource

Paeonia lactiflflora Pall. has a long edible and medicinal history because of the very high content of biologically active compounds. However, little information is available about the metabolic basis of pharmacological values of P. lactiflora flowers. In this study, we investigated metabolites in the different parts of P. lactiflora flowers, including petal, stamen petaloid tissue and stamen, by widely targeted metabolomics approach. A total of 1102 metabolites were identified, among which 313 and 410 metabolites showed differential accumulation in comparison groups of petal vs. stamen petaloid tissue and stamen vs. stamen petaloid tissue. Differential accumulated metabolites analysis and KEGG pathway analysis showed that the flavonoids were the most critical differential metabolites. Furthermore, difference accumulation of flavonoids, phenolic acids, tannins and alkaloids might lead to the differences in antioxidant activities and tyrosinase inhibition effects. Indeed, stamen petaloid tissue displayed better antioxidant and anti-melanin production activities than petal and stamen through experimental verification. These results not only expand our understanding of metabolites in P. lactiflora flowers, but also reveal that the stamen petaloid tissues of P. lactiflora hold the great potential as promising ingredients for pharmaceuticals, functional foods and skincare products.

The use of alternative food sources to improve health and guarantee access and food intake

To feed and provide Food Security to all people in the world is a big challenge to be achieved with the 2030 Agenda. Undernutrition and obesity are to the opposite of a healthy nutritional status. Both conditions are associated with unbalanced nutrition, absence of food or excess of non-nutritive foods intake. These two nutritional conditions associated with food production are closely related to some goals highlighted by the United Nations in the 2030 Agenda to achieve sustainable world development. In this context, the search for alternative foods whose sustainable production and high nutritional quality guarantee regular access to food for the population must be encouraged. Alternative foods can contribute to Food Security in many ways as they contribute to the local economy and income generation. Popularizing and demystifying the uses of unconventional food plants, ancestral grains, flowers, meliponiculture products, and edible insects as sources of nutrients and non-nutrients is another challenge. Herein, we present an overview of alternative foods - some of them cultivated mostly in Brazil - that can be explored as sources of nutrients to fight hunger and malnutrition, improve food production and the economic growth of nations.

Spectrum-effect relationship between UPLC fingerprints and antidiabetic and antioxidant activities of Rosa rugosa

In this study, the antidiabetic and antioxidant properties of the chemical constituents of Rosa rugosa Thunb. (R. rugosa) was evaluated through analysis of spectrum-effect relationship. The ultra-performance liquid chromatography (UPLC) fingerprints of 21 batches of R. rugosa were evaluated by similarity analysis (SA) and hierarchical clustering analysis (HCA). The 28 common components were identified by ultra-high-performance liquid chromatography coupled to quadrupole-orbitrap high resolution mass spectrometry (UHPLC-Q-orbitrap-HRMS/MS). Meanwhile, the antidiabetic activities and antioxidant activities of 21 batches of R. rugosa were estimated in vitro. Besides, four chemometrics named principal component analysis (PCA), grey correlation analysis (GRA), partial least squares regression (PLSR) and the bivariate correlations analysis (BCA) were applied to construct spectrum-effect relationship between the UPLC fingerprints and biological activities of R. rugosa. The spectrum-effect relationship study revealed that di-O-galloyl-HHDP-glucoside, galloyl-HHDP-glucoside and avicularin were more relevant to antidiabetic activity. Di-O-galloyl-HHDP-glucoside, galloyl-HHDP-glucoside and ellagic acid were the main antioxidant components of R. rugosa. The current bioassay and spectrum-effect relationships are proper for associating sample quality with the active ingredient, and our finding would provide foundation and further understanding of the quality evaluation and quality control of R. rugosa.

Neuroprotective Effects of Coreopsis lanceolata Flower Extract against Oxidative Stress-Induced Apoptosis in Neuronal Cells and Mice

Coreopsis lanceolata L. is a perennial plant of the family Asteraceae, and its flower is known to contain flavonoids with various bioactivities. We evaluated the effect of Coreopsis lanceolata L. flower (CLF) extracts on H2O2-induced oxidative stress (OS) in neuronal cells and mouse neurons. The flowering part of CL was used as CLF1 (70% ethanol extract) and CLF2 (water extract), and 10 types of phenolic compounds were quantified using high-performance liquid chromatography. To evaluate the neuroprotective effects of CLF, the antioxidant activities of the extracts were measured, and the expression levels of antioxidant enzymes and proteins related to OS-induced apoptosis in neuronal cells and mouse neurons treated with the extracts were investigated. In the in vitro study, CLF ameliorated H2O2-induced oxidative stress and induced the expression of antioxidant enzymes in PC12 cells. Furthermore, CLF1 enhanced the expression of the Bcl-xL protein but reduced the expression of Bax and the cleavage of caspase-3. In the same manner, CLF1 showed neuroprotective effects against OS in vivo. Pretreatment with CLF1 (200 mg/kg) increased the Bcl-2 protein and decreased Bax compared with the 1-methyl-4-phenylpyridinium ion (MPP+)-treated C57BL/6 mice model group. Our results suggest that the protective effects of CLF1 on MPP+-induced apoptosis may be due to its anti-apoptotic activity, through regulating the expression of the Bcl-2 family. CLF1 exerts neuroprotective effects against OS-induced apoptosis in PC12 cells in a Parkinson's disease model mouse. This effect may be attributable to the upregulation of Bcl-2 protein expression, downregulation of Bax expression, and inhibition of caspase-3 activation. These data indicate that CLF may provide therapeutic value for the treatment of progressive neurodegenerative diseases.

Nutraceutical potential of dietary phytochemicals in edible flowers-A review

Edible flowers have been in traditional cuisine and phytotherapy for centuries. Recently, the consumption of edible flowers has increased significantly as the phytochemicals in them are known to have numerous health benefits. Information on nutraceutical potentials and health benefits of the phytochemicals available in different varieties of edible flowers and their uses are discussed. It is found that the major groups of dietary phytochemicals in edible flowers include flavonoids, phenolic acids, and anthocyanins and they are capable of exerting antioxidant, anti-inflammatory, anti-diabetic, anticancer, cardioprotective, hepatoprotective gastroprotective, and genoprotective effects. PRACTICAL APPLICATIONS: Edible flowers are good sources of phytochemicals and possessing antioxidant, anti-inflammatory properties, anticancer, anti-diabetic, and cardio-protective properties. However, many edible flowers remain unexplored and underutilized. This review gives eye openings that more in-depth investigations need to be conducted on different edible flowers and they need to be incorporated into commercialized foods and drugs or need to be used for novel nutraceutical development to deliver the potential health benefits to consumers.

An update on the health benefits promoted by edible flowers and involved mechanisms

The aim of this review is to provide new findings on health effects of edible flowers since 2015. The antioxidant, anti-inflammatory, anti-cancer, hepatoprotective, neuroprotective, anti-diabetic, anti-osteoporosis, anti-obesity, and anti-hypertensive have been reviewed, and the effective concentrations of flower extracts have been summarized. Among all the health benefits mentioned, anti-osteoporosis, anti-obesity, and anti-hypertensive have rarely been mentioned before 2015. Some health benefits mechanisms of edible flowers were discussed frequently after 2015. Some newly found phytochemicals such as polysaccharides were shown to be beneficial to human health. Species of Rosa, Chrysanthemum, and Osmanthus have been reported to exert different health effects on human. For the toxicity studies, the safe level of flower extracts in cell and animal models were at hundreds of parts per million (ppm) level. In consideration of health promoting effects and toxicities of edible flowers, they could serve as potential natural health products for different health benefits.

Hexavalent chromium-induced autophagic death of WRL-68 cells is mitigated by aqueous extract of Cuminum cyminum L. seeds

In this study, we assessed the potential of aqueous extract (CSE_aq) of Cuminum cyminum L. (cumin) seeds in protecting WRL-68 cells from hexavalent chromium [Cr(VI)]-induced oxidative injury. Cells exposed to Cr(VI) (10 μM CrO₃) for 24 h demonstrated a twofold increase in ROS, which, in turn, led to extensive oxidative stress, consequently causing colossal decline in cell viability (by 58.82 ± 9.79%) and proliferation (as was evident from a reduced expression of Ki-67, a proliferation marker). Immunofluorescence studies showed that Cr(VI) diminished the expressions of mTOR and survivin in WRL-68 cells. It also led to a substantial elevation of BECN1 expression, which suggested autophagy. Overall, our results indicated that 24 h exposure of WRL-68 cells to Cr(VI) caused oxidative stress-induced autophagic cell death. CSE_aq was found to protect WRL-68 cells from the same fate by refurbishing their viability and proliferation in a dose-dependent manner. The extract reduced ROS in these cells, which consequently decreased the degree of autophagic cell death by restoring expressions of mTOR, survivin and BECN1 to their respective normal levels. Biochemical assays revealed that CSE_aq is rich in phenolic constituents. Total phenolic content of CSE_aq demonstrated positive correlations with (i) its antioxidant potential, (ii) its alleviation of cellular oxidative stress and (iii) its cytoprotective efficacy in Cr(VI)-treated WRL-68 cells. We also identified the major phenolic constituents of CSE_aq. Our study suggested that polyphenols in CSE_aq might be responsible for protecting WRL-68 cells from Cr(VI)-governed oxidative assault that would have otherwise led to survivin/mTOR-mediated autophagic death.

Isolation of Strong Antioxidants from Paeonia Officinalis Roots and Leaves and Evaluation of Their Bioactivities

Paeonia officinalis extracts from leaves and roots were tested for their antioxidant potential using in vitro chemical (Folin-Ciocalteu, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2′-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS), oxygen radical absorbance capacity (ORAC), hydroxyl radical antioxidant capacity (HORAC), hydroxyl radical scavenging capacity HOSC)) and cellular antioxidant activity (CAA) assays. Leaf extracts were stronger antioxidants than root extracts, while methanol was a more effective solvent than water in chemical assays. However, the selected water extract of leaves was a stronger antioxidant in CAA than the methanol extract (0.106 vs. 0.046 µmol quercetin equivalents/mg). Twenty compounds were identified by ultra performance liquid chromatography-quadrupole-time-of-flight (UPLC-Q-TOF) mass spectrometer, while on-line screening of their antioxidant capacity by high performance liquid chromatography (HPLC) with a DPPH^•-scavenging detector revealed that gallic acid derivatives are the major peony antioxidants. Root water and leaf methanol extracts inhibited α-amylase in a dose dependent manner. The IC₅₀ value for the strongest inhibitor, the methanol extract of leaves, was 1.67 mg/mL. In addition, the cytotoxicity assessment of extracts using human Caco-2 cells demonstrated that none of them possessed cytotoxic effects.

Primary Screening of Antioxidant Activity, Total Polyphenol Content, Carotenoid Content, and Nutritional Composition of 13 Edible Flowers from Japan

Thirteen edible flowers, which are used as food ingredients in Japan, were evaluated as possible sources of antioxidants and biological compounds. The nutritional composition, total polyphenol content (TPC), carotenoid content, and antioxidant activity of the edible flowers were determined based on the oxygen radical absorbance capacity (ORAC). Water was the main constituent of edible flowers, and carbohydrates were the primary macronutrients. The TPC of the edible flowers varied from 1.47 to 13.08 mg gallic acid equivalent/g fresh weight (FW). Carotenoids, including β-carotene and β-cryptoxanthin, were detected mainly in the edible flowers with petal colors ranging from yellow to orange, but especially in primula and cosmos yellow flowers, which have yellow petals. The ORAC value of the hydrophilic extract (HORAC) of edible flowers was higher than the ORAC value of the lipophilic extract (LORAC). The total antioxidant capacity (TAC) ranged from 33.03 to 320.36 μM Trolox equivalent/g FW. The highest TPC and TAC were observed in cosmos yellow flowers. On the basis of Pearson's correlation coefficient, the HORAC value and the TPC of the analyzed edible flowers were highly correlated (r=0.736). This preliminary study indicates that edible flowers are a potential source of antioxidants, and the addition of edible flowers to the human diet may be associated with health benefits.

Physiochemical properties of petunia edible flowers grown under saline conditions and their postharvest performance under modified atmosphere packaging and ethanol application

BACKGROUND

Edible flowers have both great nutritional value and sensory appeal; however, their shelf-life is limited to a few days because they are highly perishable.

RESULTS

The impact of postharvest ethanol (ET) treatment and modified atmosphere packaging (MAP) on the quality and storage of edible flowers collected from short-term salt-stressed plants was tested. Hydroponically grown petunia (Petunia x hybrita L.) plants were subjected to salinity (0-50-100 mmol L^-1 NaCl) and harvested flowers were stored for up to 14 days in MAP and/ET vapours. The salinity of 100 mmol L^-1 NaCl decreased plant biomass and negatively affected physiological processes as a result of stomata closure. Flower polyphenols, antioxidants, carotenoids and anthocyanins increased with 50 mmol L^-1 of NaCl, indicating a higher nutritional value. Short-term exposure of petunia to salinity decreased the flower N, K and Ca concentrations. During storage for 7 days, salinity lead to deteriorated flowers that showed browning as a result of tissue breakdown, whereas CO₂ production and weight loss were unaffected by salinity. After 14 days of storage, salinity decreased flower respiration and increased weight loss, whereas ET application completely destroyed the flowers. Carotenoids and anthocyanins were decreased by a combination of salinity and ET. Petunia flowers revealed the induction of both non-enzymatic (i.e. proline content) and enzymatic (catalase) mechanisms to overcome the stress caused by salinity at harvest stage and/or ethanol at storage.

CONCLUSION

The results of the present study demonstrate that a short-stress salinity of 50 mmol L^-1 NaCl can be used for petunia growth and also that flowers of nutritional value can be stored for up to 7 days, whereas ET application failed to preserve petunia flowers. © 2019 Society of Chemical Industry.

The protective effects of Sauropus spatulifolius on acute lung injury induced by lipopolysaccharide

BACKGROUND

Sauropus spatulifolius Beille (named 'Long-Li-Ye' in China) is used to make 'herbal tea' to prevent pneumonia. This study aimed to evaluate the antioxidant activities in vitro and the protective effects of Long-Li-Ye on acute lung injury (ALI) induced by lipopolysaccharide (LPS).

RESULTS

The supernatant after ethanol addition to Long-Li-Ye water extract (LLYCSL) and the resin eluting fraction of LLYCSL (LLY40) showed strong antioxidant activities in vitro. LLYCSL and LLY40 could attenuate ALI via decreasing myeloperoxidase activity, increasing superoxide dismutase activity and decreasing the levels of tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β) and IL-6. In addition, LLY40 could increase catalase activity, increase the levels of IL-10, IL-4 and IL-13 and decrease the TNF-α/IL-10 ratio.

CONCLUSION

Long-Li-Ye could be used as a natural antioxidant for food production and functional food or dietary supplementation for people with ALI. © 2018 Society of Chemical Industry.

In Vitro Antioxidant Activities of Phenols and Oleanolic Acid from Mango Peel and Their Cytotoxic Effect on A549 Cell Line

Mango peel, the main by-product of juice processing, possesses appreciable quantities of bioactive phenolic compounds and is worthy of further utilization. The present work reports for the first time the HPLC analysis and in vitro antioxidant evaluation of mango peel phenols (MPPs) and their cytotoxic effect on the A549 lung cancer cell line. These results indicated that mango peel has the total phenolic content of 723.2 ± 0.93 mg·kg−1 dry mango peel (DMP), which consisted mainly of vanillic aldehyde, caffeic acid, chlorogenic acid, gallic acid, procyanidin B₂ and oleanolic acid. Antioxidant assays showed that MPPs had strong antioxidant activities, with 92 ± 4.2% of DPPH radical scavenging rate, 79 ± 2.5% of ABTS radical inhibition rate and 4.7 ± 0.5 μM Trolox equivalents per kg−1 DMP of ferric reducing power. Gallic acid possess a stronger antioxidant capacity than other phenols. In vitro cytotoxic tests suggested that mango peel extract (MPE) had an IC50 value of 15 mg·mL−1 and MPPs had a stronger inhibitory effect on the A549 cell line. Oleanolic acid exhibited the strongest cytotoxicity, with an IC50 value of 4.7 μM, which was similar with that of the positive control 5-fluorouracil.

Bioaccessibility and Absorption Mechanism of Phenylethanoid Glycosides Using Simulated Digestion/Caco-2 Intestinal Cell Models

Acteoside and salidroside are major phenylethanoid glycosides (PhGs) in Osmanthus fragrans Lour. flowers with extensive pharmacological activities and poor oral bioavailability. The absorption mechanisms of these two compounds remain unclear. This study aimed to investigate the bioaccessibility of these compounds using an in vitro gastrointestinal digestion model and to examine the absorption and transport mechanisms of PhGs using the Caco-2 cell model. The in vitro digestion model revealed that the bioaccessibility of salidroside (98.7 ± 1.35%) was higher than that of acteoside (50.1 ± 3.04%), and the superior bioaccessibility of salidroside can be attributed to its stability. The absorption percentages of total phenylethanoid glycoside, salidroside, and acteoside were 1.42-1.54%, 2.10-2.68%, and 0.461-0.698% in the Caco-2 model, respectively. Salidroside permeated Caco-2 cell monolayers through passive diffusion. At the concentration of 200 μg/mL, the apparent permeability ( P_app) of salidroside in the basolateral (BL)-to-apical (AP) direction was 23.7 ± 1.33 × 10^-7 cm/s, which was 1.09-fold of that in the AP-to-BL direction (21.7 ± 1.38 × 10^-7 cm/s). Acteoside was poorly absorbed with low P_app (AP to BL) (4.75 ± 0.251 × 10^-7 cm/s), and its permeation mechanism was passive diffusion with active efflux mediated by P-glycoprotein (P-gp). This study clarified the bioaccessibility, absorption, and transport mechanisms of PhGs. It also demonstrated that the low bioavailability of acteoside might be attributed to its poor bioaccessibility, low absorption, and P-gp efflux transporter.