Sinapic Acid Derivatives Research Articles

Effects of microwave irradiation on the distribution of sinapic acid and its derivatives in rapeseed and the antioxidant evaluation

The purpose of the study was to observed the effect of microwave irradiation on the distribution of sinapic acid and its derivatives in hull, endosperm, cotyledon and entire rapeseed. Meanwhile, total phenolic conetent, DPPH and FRAP scavenging capacity of rapeseed were evaluated. Eight main sinapic acid derivatives including sinapine (SP), sinapoyl-glucoside (SG), quercetin-sinapoyl-di-hexosepentose (QSDG), sinapic acid (SA), sinapoyl-malic acid (SM), disinapoyl gentiobioside (DSGG), sinapoylcholine thiocyanate-glucoside (SPTG) and canolol were confirmed in rapeseed by using UPLC-QTOF-MS/MS. After microwave irradiation, canolol in hull, cotyledon, endosperm and whole rapeseed increased by 11.1, 90.0,49.8 and 67.4 mg/100 g, respectively. SP in cotyledon, endosperm and whole rapeseed decreased by 15.9%, 29.1% and 22.1%, respectively. No direct connection was found between canolol formation and sinapine pyrolysis. SG, SA, SM, DSGG and SPTG in endosperm, cotyledon and entire rapeseed decreased significantly except for QSDG. There was no significant different in total phenolic content, DPPH and FRAP scavenging capacity before or after microwave. SP and SA exhibited similar DPPH and FRAP scavenging capacity which were stronger than others. These results indicated microwave irradiation affects the distribution of sinapic acid and its derivatives and contributes to the formation of canolol in rapeseed.

Biological Activity of Sinapic Acid Derivatives Isolated from Raphanus sativus

Biological Activity of Sinapic Acid Derivatives Isolated from Raphanus sativus

Changes in contents of phenolic compounds (sinapic acid derivatives) in seeds of Brassica napus L.under adverse storage conditions.

The quality of rapeseed oil depends to a considerable degree on raw material quality. Negli- gence in maintaining the appropriate conditions during long-term rapeseed storage (excessively high humid- ity and temperature) may contribute to a deterioration of seed quality, as a result of microbial growth and changes in native antioxidant contents. The aim of this study was to investigate the effect of inappropriate storage conditions on changes in sinapic acid derivative content, which is the main phenolic compound in rapeseeds. The material used for tests was canola cv. PR 46 W14. Seeds with a 13.5% moisture content were stored for 21 days in a thermo-hygrostat chamber, ensuring rapeseed storage under constant humidity and temperature conditions. In this study, the level of mould fungi was analysed using the plate method, while those of sinapic acid derivatives were determined using the HPLC-DAD method. Intensive growth of mould fungi in the rapeseeds was observed after 6 days of storage. Changes were recorded in sinapic acid derivative contents, which are the main phenolic compounds in rapeseed. The level of phenolic compounds found in the bound form (sinapin; sinapic acid methyl ester; 1,2-disinapoyl- dihexoside; 1,2-disinapoyl-hexoside and 1,2,2’-trisinapoyl-dihexoside) decreased. At the same time, an in- crease was recorded in trans-sinapic acid content (by 63%). Both qualitative and quantitative changes in phenolic compounds may be connected with the development of fungal microflora in stored rapeseeds. Only adequate storage conditions for the oil raw mate- rial, such as rapeseeds, may ensure good quality in the final product, in this case, rapeseed oil.

Changes in contents of phenolic compounds (sinapic acid derivatives) in seeds of Brassica napus L.under adverse storage conditions [pdf

Changes in contents of phenolic compounds (sinapic acid derivatives) in seeds of Brassica napus L.under adverse storage conditions [pdf

Lipid oxidation and changes in the phenolic profile of watercress (Nasturtium officinale L.) leaves during frying

Watercress leaves were fried in sunflower oil and analysed for lipid oxidation and phenolic compounds by high-performance liquid chromatography with diode array detection (HPLC–DAD). Results revealed that total phenolic contents and radical scavenging activity decreased significantly at the initial stages and were stable in frying oil, indicating stability of frying oil. A significant increase occurred in chlorophylls of watercress leaves and frying oil. HPLC chromatograms showed a total of 12 phenolic compounds containing caftaric acid (17.3–31.8 µg/g), sinapic acid derivative (11.2–14.4 µg/g), 4-O-caffeoylquinic acid (9.98–12.8 µg/g), 4-O-feruloyl quinic acid (8.47–13.4 µg/g), caffeoyl feruloyl quinic acid (7.31–11.7 µg/g) and 5-O-caffeoylquinic acid (3.73–6.51 µg/g) as major compounds. A significant increase in the caffeic acid, caffeoyl hexose, chlorogenic acid, caftaric acid, coumaric acid derivatives and 3, 4-di-O-caffeoylquinic acid was observed, while a decrease occurred in Sinapic acid derivative, 5-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, 4-O-feruloyl quinic acid and caffeoyl feruloyl quinic acid. Frying of watercress leaves increase the bioavailability of medicinally important phenolic compounds and also help to stabilise the frying oil.

Evaluation of Volatile Profile, Fatty Acids Composition and in vitro Bioactivity of Tagetes minuta Growing Wild in Northern Iran.

Purpose: The aim of the present study was to investigate the chemical properties of wild Tagetes minuta L. (family Astreacea) collected from Northern Iran during the flowering period concerning the chemical combination of the essential oil along with its antioxidant properties and composition of fatty acids.Methods: The essential oil of the plant was extracted by a Clevenger approach and analyzed using gas chromatography-mass spectroscopy (Capillary HP-5ms GC/MS Column). Fatty acid contents of this species as a result of hexane extraction were analyzed by means of gas chromatography (GC-FID) while their phenolic contents were analyzed by high performance liquid chromatography (HPLC-UV). In this research also the total polyphenolic (TPC) and total flavonoid (TFC) content was determined spectrophotometrically while the antioxidant activity was evaluated using the DPPH (2,2'-diphenyl-1-picrylhydrazyl) bleaching method.Results: GC/MS analysis of the essential oil identified monoterpenoid fractions (52.13%) as the main components and among them dihydrotagetone (23.44%) and spathulenol (10.56%) were the predominant compounds. The evaluation of fatty acid content revealed that saturated acids were prevailing compounds and the major components are: palmitic (30.74±0.4%) and capric (24.15±0.5%) acids. Chromatographic separation of its phenolic contents indicated that this herb contain sinapic acid derivatives rather than hydroxybenzoic acid derivatives. Also the essential oil showed an effective antioxidant capacity (TPC=153.27±0.9 mg/g, TFC=63.79±0.1 mg/g, IC50 = 29.31±0.8 µg/ml).Conclusion: The results proved that the plant could be used for nutritional and pharmaceutical purposes.

Sinapic Acid Derivatives as Potential Anti-Inflammatory Agents: Synthesis and Biological Evaluation.

Transcription factor NF-κB and relevant cytokines IL-6 and IL-8 play a pivotal role in the pathogenesis of inflammation. Sinapic acid is a natural product and was demonstrated to possess anti-inflammatory activity. In this paper, we synthesized a series of sinapic acid derivatives and evaluated their anti-inflammatory effects. The result suggested that all of the targets compounds 7a-j inhibit NF-κB activation and decrease IL-6 and IL-8 expression in BEAS-2B cells. By our biological assays, we found that all of the prepared compounds displayed stronger anti-inflammatory activities than their precursor sinapic acid. Especially, compounds 7g and 7i, with electron-drawing groups (nitro and fluoro moieties) in the benzimidazole ring, exhibited remarkable anti-inflammation activity, which was even stronger than the reference drug dexamethasone.

Identification and quantification of phenolic compounds through reversed phase HPLC-DAD method in sunflower seeds under various treatments of potassium nitrate, zinc sulphate and gibberellic acid

Phenolic compounds were extracted from seeds of eight varieties i.e. Rising Sun, SMH-0907, Ausigold-7, SMH-0939, US-444, Hysun-33, SMH-0917 and HS-K6 of sunflower and characterized by HPLC-DAD method. Quantification of individual compounds was carried out by external calibration. Total of 15 phenolic compound were identified, namely hydroxybenzoic acid, hydroxybenzoyl glucose, caftaric acid, rosmanol, gallic acid derivative, 3,4-di-O-caffeoylquinic acid, 3,5-di-O-caffeoylquinic acid, caffeic acid, pro-anthocynidin B1, rosmannic acid, sinapic acid derivative, caffeic acid derivative 1, caffeic acid derivative 2, caffeoylmalic acid derivative and quercetin derivative in the seeds of sunflower. Different treatments of potassium nitrate, zinc sulphate, and gibberellic acid showed significant effect on the biosynthesis of phenolic compound as compared to control plants. Among the 15 compounds analyzed 3,4-di-O-caffeoylquinic acid was predominant compound in the seeds. The current results demonstrate that this method can be efficiently used for the identification and quantification of phenolic compound in sunflower seeds.

Drought-related secondary metabolites of barley (Hordeum vulgare L.) leaves and their metabolomic quantitative trait loci.

Determining the role of plant secondary metabolites in stress conditions is problematic due to the diversity of their structures and the complexity of their interdependence with different biological pathways. Correlation of metabolomic data with the genetic background provides essential information about the features of metabolites. LC-MS analysis of leaf metabolites from 100 barley recombinant inbred lines (RILs) revealed that 98 traits among 135 detected phenolic and terpenoid compounds significantly changed their level as a result of drought stress. Metabolites with similar patterns of change were grouped in modules, revealing differences among RILs and parental varieties at early and late stages of drought. The most significant changes in stress were observed for ferulic and sinapic acid derivatives as well as acylated glycosides of flavones. The tendency to accumulate methylated compounds was a major phenomenon in this set of samples. In addition, the polyamine derivatives hordatines as well as terpenoid blumenol C derivatives were observed to be drought related. The correlation of drought-related compounds with molecular marker polymorphisms resulted in the definition of metabolomic quantitative trait loci in the genomic regions of single-nucleotide polymorphism 3101-111 and simple sequence repeat Bmag0692 with multiple linkages to metabolites. The associations pointed to genes related to the defence response and response to cold, heat and oxidative stress, but not to genes related to biosynthesis of the compounds. We postulate that the significant metabolites have a role as antioxidants, regulators of gene expression and modulators of protein function in barley during drought.

Influence of harvest season on chemical composition and bioactivity of wild rue plant hydroalcoholic extracts

The rue (Ruta graveolens) copiousness in rural areas of the Campania Region based a thorough chemical and biological investigation aimed at exploring the seasonal variability of phenol constituents in rue leaves and its influence on their antioxidant, cytotoxic and anti-inflammatory capabilities. To this purpose, hydroalcoholic extracts were prepared from plant samples seasonally collected. LC-ESI-MS/MS techniques were employed to analyze qualitatively and quantitatively the seasonal rue phenol content, whereas different chemical antioxidant assays (by DPPH, ABTS, Fe3+ RP, ORAC, and FCR methods) and XTT redox metabolic activity assay were performed to screen the seasonal phenol complex-related antioxidant and cytotoxic power. The ability of the rue leaf extracts to counteract cyclooxygenase-2 (COX-2) expression was also evaluated. Data obtained highlighted that the adopted extraction procedure markedly pauperized the furanocoumarin content in all the prepared rue extracts. Flavonol glycosides, along with the flavone acacetin and two sinapic acid derivatives were the main constituents of the spring harvest-derived extract, which exerted the highest antioxidant capability in cell-free systems and was capable to inhibit COX-2 synthesis by 44% comparably to dexamethasone, used as positive control. Data provide new insights for developing a proper management of rue plants for new safe industrial purposes in herbal medicine field.

Ultrafast Photoprotecting Sunscreens in Natural Plants.

We explore the ultrafast photoprotective properties of a series of sinapic acid derivatives in a range of solvents, utilizing femtosecond transient electronic absorption spectroscopy. We find that a primary relaxation mechanism displayed by the plant sunscreen sinapoyl malate and other related molecular species may be understood as a multistep process involving internal conversion of the initially photoexcited 1(1)ππ* state along a trans-cis photoisomerization coordinate, leading to the repopulation of the original trans ground-state isomer or the formation of a stable cis isomer.

Phenolic profile and antioxidant potential of wild watercress (Nasturtium officinale L.).

Phenolic profile, antioxidant potential and pigment contents of wild watercress (Nasturtium officinale L.) were studied to assess the potential for future studies and its applications in neutraceuticals and bioactive functional ingredients. Different extracts of watercress (roots, stem and leaves) were analysed for pigment composition, total phenolic contents, and radical scavenging activity. The phenolic profile of the leaves and roots was studied using reversed phase HPLC–DAD. Results showed that total phenolic compounds in all samples were higher in the methanolic extracts than its corresponding aqueous extracts. The RSA of methanolic extracts was higher than aqueous extracts. Fourteen phenolic compounds were identified in the leaves, where coumaric acid and its derivatives, caftaric acid and quercetin derivatives were present in higher amounts. In roots, a total of 20 compounds was tentatively identified, with coumaric acid and its derivatives, sinapic acid, caftaric acid and quercetin derivatives were the major phenolic compounds. In conclusion, watercress has significant antioxidant activity and contains important phenolic compounds, which could be of potential biological interest.

Antioxidant activity of phenolic compounds from canola (Brassica napus) seed

The antioxidant activities of various extracts from canola (Brassica napus) seed were investigated using the DPPH assay, ABTS radical assay, and reducing power. An 80% methanol extract from canola seed was sequentially fractionated and separated according to the solvent polarity and Sephadex LH-20 chromatography, respectively. The antioxidant activities of various extracts and their total phenolic content (TPC) and total flavonoid content (TFC) were closely correlated, resulting in correlation coefficient values higher than 0.87. Of all extracts, the sub-fraction 3 had the highest TPC (462.3 μg/mg) and TFC (75.4 μg/mg) while it showed the lowest EC50 value (183.1 μg/mL). The EC50 value of sub-fraction 3 measured using the DPPH radical assay was 1.3 times lower than that of butylated hydroxytoluene (BHT). The major free phenolic compound was trans-sinapic acid (193.4 μg/mg) and sinapic acid derivatives identified as 1-O-β-d-glucopyranosyl sinapate and 1,2-di-O-sinapoyl-β-d-glucose in sub-fraction 3.

Identification and quantification of canolol and related sinapate precursors in Indian mustard oils and Canadian mustard products

AbstractCanadian condiment yellow mustard seeds (also called white), oriental and brown mustard seeds and flour extracts and commercially produced Indian mustard oils were examined for bioactive phenolics primarily to identify the antioxidant properties. Phenolic compounds, namely sinapic acid, sinapoyl glucose and canolol, were quantified using high‐performance liquid chromatographic (HPLC) coupled with a diode array detector (DAD). Canolol was detected and confirmed in trace amounts for the first time in commercial oils that had not been preheated specific for canolol production, most likely due to heat applied during processing. Sinapic acid, sinapine and canolol derived from unheated/unroasted mustard seeds and canola extracts were confirmed utilizing HPLC‐DAD, ultra‐performance liquid chromatography‐tandem‐mass spectrometry (UPLC‐tandem‐MS) and nuclear magnetic resonance (NMR) spectroscopy.Practical applications: Oilseeds canola and mustard contain significant amounts of phenolic compounds, principally sinapic acid derivatives. The level and functionality of these phenolic is highly influenced by the processing conditions. In the current study, the phenolic composition of some commercial mustard seed, oil, meal and flour samples were profiled with special focus on the occurrence of canolol, the decarboxylation product of sinapic acid. This study suggests that optimizing the crushing, pressing, or extraction steps during processing is crucial to enrich mustard and canola products with benefits associated with these bioactives, especially canolol.The existence of sinapic acid derivatives was confirmed in the 70% aqueous methanolic extracts of commercial mustard products such as deheated mustard flour and oil. Extracts of mustard, in addition to canola, contain significant amounts of phenolics, mainly sinapine. Traditional ghani pressing, cold pressing and/or screw expeller pressing hold potential for enriching mustard and sinapate‐rich oil with benefits associated with canolol.

Plant sunscreens in the UV-B: ultraviolet spectroscopy of jet-cooled sinapoyl malate, sinapic acid, and sinapate ester derivatives.

Ultraviolet spectroscopy of sinapoyl malate, an essential UV-B screening agent in plants, was carried out in the cold, isolated environment of a supersonic expansion to explore its intrinsic UV spectral properties in detail. Despite these conditions, sinapoyl malate displays anomalous spectral broadening extending well over 1000 cm(-1) in the UV-B region, presenting the tantalizing prospect that nature's selection of UV-B sunscreen is based in part on the inherent quantum mechanical features of its excited states. Jet-cooling provides an ideal setting in which to explore this topic, where complications from intermolecular interactions are eliminated. In order to better understand the structural causes of this behavior, the UV spectroscopy of a series of sinapate esters was undertaken and compared with ab initio calculations, starting with the simplest sinapate chromophore sinapic acid, and building up the ester side chain to sinapoyl malate. This "deconstruction" approach provided insight into the active mechanism intrinsic to sinapoyl malate, which is tentatively attributed to mixing of the bright V ((1)ππ*) state with an adiabatically lower (1)nπ* state which, according to calculations, shows unique charge-transfer characteristics brought on by the electron-rich malate side chain. All members of the series absorb strongly in the UV-B region, but significant differences emerge in the appearance of the spectrum among the series, with derivatives most closely associated with sinapoyl malate showing characteristic broadening even under jet-cooled conditions. The long vibronic progressions, conformational distribution, and large oscillator strength of the V (ππ*) transition in sinapates makes them ideal candidates for their role as UV-B screening agents in plants.

Value-added potential of expeller-pressed canola oil refining: characterization of sinapic acid derivatives and tocopherols from byproducts.

Valuable phenolic antioxidants are lost during oil refining, but evaluation of their occurrence in refining byproducts is lacking. Rapeseed and canola oil are both rich sources of sinapic acid derivatives and tocopherols. The retention and loss of sinapic acid derivatives and tocopherols in commercially produced expeller-pressed canola oils subjected to various refining steps and the respective byproducts were investigated. Loss of canolol (3) and tocopherols were observed during bleaching (84.9%) and deodorization (37.6%), respectively. Sinapic acid (2) (42.9 μg/g), sinapine (1) (199 μg/g), and canolol (344 μg/g) were found in the refining byproducts, namely, soap stock, spent bleaching clay, and wash water, for the first time. Tocopherols (3.75 mg/g) and other nonidentified phenolic compounds (2.7 mg sinapic acid equivalent/g) were found in deodistillates, a byproduct of deodorization. DPPH radical scavenging confirmed the antioxidant potential of the byproducts. This study confirms the value-added potential of byproducts of refining as sources of endogenous phenolics.

Anthocyanins profile and antioxidant capacity of red cabbages are influenced by genotype and vegetation period

The profile and content of anthocyanins in five red cabbage varieties were analyzed using HPLC–DAD–MS/MS method. The antioxidant capacity of red cabbages was evaluated using five in vitro assays. Red cabbages contained twenty different anthocyanins with the main structure of cyanidin-3-diglucoside-5-glucosides. The presence of nonacylated, monoacylated and diacylated form was identified. Nonacylated and diacylated with sinapic acid derivatives of cyanidin-3-diglucoside-5-glucoside were predominant. The content of anthocyanins varied significantly in plants grown in two different years (P<0.05). Moreover, the vegetation period length was demonstrated to affect the anthocyanins profile. The extract of red cabbages scavenged radicals and their antiradical potential differed significantly across the varieties (P<0.05). In addition, red cabbage antioxidant capacity was positively and significantly correlated with anthocyanins content (P<0.05). This study demonstrates that red cabbage varieties possess own anthocyanins fingerprint and specific antioxidant capacity, which are also under the influence of vegetation period.

Effect of Conventional and Microwave Toasting on Sinapic Acid Derivatives and Canolol Content of Canola

Canola seeds were subjected to conventional and microwave heat treatments to investigate changes in the phenolic profile of defatted meal and oil obtained from the toasted seeds. Different temperature (120–200 °C) and time (5–20 min) combinations were applied for toasting the seeds in a conventional oven. The seeds were also toasted using a microwave oven at 300 Watt power level with and without steaming. Phenolics were extracted from the defatted meal and oil of raw and toasted seeds. The main phenolic compounds namely sinapine (SP), sinapoyl glucose (SG), sinapic acid (SA) and canolol were identified and quantified by HPLC-DAD. Total phenolics and SA derivatives in the meal were found to decrease in both toasting treatments. Canolol was formed in the oil and subsequently increased with increasing toasting temperature up to 200 °C. The optimum toasting conditions under which the canolol content of the oil showed the highest increment rate (more than 2200 folds) were found to be 200 °C for 15 min in the conventional oven. However, the optimum microwave toasting conditions were 20 min with steam which increased canolol content by more than 1700 folds. Keywords: Canola, canolol, sinapic acid derivatives, toasting.

Biophenols and Antioxidant Properties of Australian Canola Meal

During the extraction of canola oil, large quantities of meal are produced. Extracting biophenols from Australian canola meal (ACM) adds value to an otherwise low-value agro-industrial byproduct. This study examined the biophenol content and the antioxidant activity of ACM, the impact of extraction conditions, and varietal differences. Sinapine was the principal biophenol in ACM. In crude and hydrolyzed extracts, 31 compounds were identified: 2 dihexosides, 2 organic acids, 4 glucosinolates, 17 sinapic acid derivatives, 2 cyclic spermidine alkaloids, caffeic acid and its dihexoside, kaempferol, and its C-glucoside. ACM showed significant free radical scavenging activity in DPPH(•) and ABTS(•+) assays. Sinapine was the chief contributor to ACM antioxidant activity, whereas kaempferol sinapoyl triglucoside isomer was the most potent antioxidant. Biophenol content ranged between 12.8 and 15.4 mg GAE/g DW. Differences among studied cultivars were generally quantitative. The Tarcoola cultivar showed the highest biophenol content and antioxidant activity.

Identification and antioxidant activity of sinapic acid derivatives in Brassica napus L. seed meal extracts

Sinapic acid and its derivatives are main phenolic compounds present in rapeseed. Identification and quantitative determination of those compounds were carried out in crude extracts as well as extracts after basic and acidic hydrolysis. The total phenolic content in the crude extracts, expressed as sinapic acid equivalent, ranged from 1577 to 1705 mg/100 g for cv. Visby and Bellevue, respectively. An increase in total phenolics contents was observed in extracts after hydrolysis in comparison to crude extracts. The predominant phenolic acids in rapeseed samples were trans‐sinapic and cis‐sinapic acids. The highest concentration of sinapic acid methyl ester (2533–2702 mg/100 g) was detected in the extract after basic hydrolysis. In turn, two sinapic acid derivatives, i.e., kaempferol 3‐dihexoside‐7‐sinapoyl‐hexoside and 3‐hexoside‐7‐sinapoyl‐hexoside, were detected in the hydrolysed extracts. Total peroxyl radical‐trapping potential (TRAP) of the investigated crude extracts amounted to 20.21 and 27.05 μM Trolox Eq/g in the case of cv. Visby and Bellevue, respectively. The increase in antioxidant activity of the analyzed extracts after basic and acidic hydrolysis was probably a result of the release of free phenolic compounds from their conjugates (esters, glycosides).Practical applications: The content and qualitative composition of the phenolic compounds in rapeseed have much influence on the stability, sensory, and nutritional characteristics of the products. During oil production process phenolic compounds may be transferred into final products and inhibit lipid oxidation. Rapeseed oil, among all commercially available oils, has the highest content of phenolic compounds, especially sinapic acid and their derivatives. That is why the antioxidant activity of phenolic compounds was investigated in the presented study. Determination of polar phenolics before and after hydrolysis indicates which compounds are responsible for antioxidant effect in oils and which are available for the human organism after digestion in the digestive tract.