Variations in phenolic composition and antioxidant properties among 15 basil (Ocimum basilicum L.) cultivars

In this study, the influences of cultivar on the phenolic composition and antioxidant properties of 15 different basil varieties was determined. Cultivar had a statistically significant effect on total phenolic levels (p < 0.001) and anthocyanin concentrations (p < 0.001). Analysis of individual phenolic acid levels by high-performance liquid chromatography showed substantial variations in the phenolic acid profiles among cultivars. Rosmarinic (p < 0.001), chicoric (p = 0.002) and caffeic (p = 0.001) acid concentrations were affected by cultivar, although caftaric acid levels (p = 0.083) were not. Nine of the cultivars in this study contained chicoric acid in higher concentrations than rosmarinic acid. These are the first basil cultivars that have been identified in which rosmarinic acid is not the dominant phenolic acid. In addition, six of the cultivars in this study had caftaric and caffeic acid concentrations that were similar or higher than rosmarinic acid levels. Cultivar also had a significant impact on both FRAP (ferric reducing antioxidant power, p = 0.007) and DPPH (2,2′-diphenyl-1-picrylhydrazyl, p = 0.004) antioxidant capacities. For the basil cultivars in this study, the individual phenolic acid composition was found to be an important factor influencing the measured antioxidant capacity.     

Chicoric acid levels in commercial basil (Ocimum basilicum) and Echinacea purpurea products

Fresh basil (Ocimum basilicum) leaves contain chicoric acid, which is the principal phenolic compound in Echinacea purpurea and purportedly an active ingredient in dietary supplements derived from E. purpurea. Here the concentrations of chicoric acid in dried and fresh basil products available to consumers, and how these concentrations compare to those from E. purpurea are reported. A wide range of chicoric acid concentrations (6.48–242.50 mg/100 g or 100 mL) were found in the dried basil flakes, fresh basil leaves, E. purpurea extracts, and E. purpurea capsules. Fresh basil leaves had higher concentrations of chicoric acid than dried basil flakes. Although E. purpurea extracts and capsules contained higher concentrations of chicoric acid than fresh basil leaves, basil could be an economical and more readily available source for chicoric acid for consumers. Additionally, cultivar selection, dehydration processing improvements, and proper storage methods may improve the final chicoric acid levels of future basil crops and products.     

Characterization of phenolics of Sarcandra glabra by non-targeted high-performance liquid chromatography fingerprinting and following targeted electrospray ionisation tandem mass spectrometry/time-of-flight mass spectrometry analyses

In this study, we successfully characterised the phenolic profiles of Sarcandra glabra (Thunb.) Nakai by high-performance liquid chromatography (HPLC) fingerprinting analyses and mass spectrometry (MS) identification. We first established a specific and valid HPLC approach for fingerprint analysis of S. glabra based on HPLC–UV detection. Using several chemometric methods such as similarity evaluation and principal components analysis, we determined herb-markers peaks from many HPLC peaks. The structures of these herb-markers were further identified targetedly by electrospray ionisation tandem mass spectrometry (ESI-MS/MS)/time-of-flight mass spectrometry (TOF-MS) analyses. As results, four phenolics, including chlorogenic acid, caffeic acid, 4-O-glucopyranosyl rosmarinic acid and rosmarinic acid, were characterised as major herb-markers for the stems of S. glabra, while another three phenolics, including kaempferol-3-O-β-d-glucuronic acid, chlorogenic acid and rosmarinic acid, were characteristic components for the leaves. The compounds may be very useful for further phenolome analysis.     

Improved loquat (Eriobotrya japonica Lindl.) cultivars: Variation of phenolics and antioxidative potential

Leaves and fruits (peel and flesh) of six improved cultivars (‘Mizuho’, ‘Néctar de Cristal’, ‘Mizauto’, ‘Mizumo’, ‘Centenária’ and ‘NE-3’) of loquat (Eriobotrya japonica Lindl.) were studied for their phenolic composition and antioxidant capacity. The analysis by HPLC-DAD-ESI-MS/MS allowed the identification of 18 compounds (8 hydroxycinnamic acid derivatives and 10 flavonoid glycosides). The quantification of the identified compounds revealed distinct profiles amongst the three analysed materials. Loquat leaves exhibited the lowest amounts of phenolics. 3- And 5-caffeoylquinic, and 5-feruloylquinic acids were the major compounds. Generally, ‘Mizauto’ cultivar presented the highest phenolic content. All loquat materials exhibited DDPH scavenging capacity, in a concentration-dependent manner, the leaves being the most active one. This effect seems to be related to the flavonoid content.     

Potassium rate alters the antioxidant capacity and phenolic concentration of basil (Ocimum basilicum L.) leaves

In the current study, we have determined how potassium rate affects the phenolic levels and antioxidant properties of three cultivars of basil (Ocimum basilicum L.) leaves: Dark Opal, Sweet Thai, and Genovese. Potassium rate increased the total phenolic concentration in basil, with basil treated at the highest potassium rate, 5.0 mM K, containing greater phenolic levels than basil treated at the lowest potassium rate, 1.0 mM K (p = 0.008). Basil grown at 5.0 mM K also had higher concentrations of rosmarinic (p = 0.005) and chicoric (p < 0.001) acids compared to lower potassium treatment levels. Correspondingly, 1.0 mM K basil had lower DPPH (2,2′-diphenyl-1-picrylhydrazyl) (p ? 0.005) and FRAP (ferric reducing antioxidant power, p = 0.043) antioxidant capacities compared to basil treated at higher potassium rates. Cultivar was also found to impact the phenolic composition and antioxidant properties of basil, with Sweet Thai having lower total phenolic concentrations and FRAP antioxidant capacities than Dark Opal and Genovese. Although not affected by potassium rate, anthocyanin concentrations varied significantly among the cultivars, with purple Dark Opal basil exhibiting higher anthocyanin levels than Sweet Thai (p = 0.003) and Genovese (p = 0.002).     

Chicoric acid from Syringodium filiforme

Detrital and living leaves of the tropical seagrass Syringodium filiforme Kütz. were screened for their phenolic contents. For the first time, the major polyphenols were identified, as chicoric acid (CA) and caftaric acid (CAF), by means of NMR and LC/MS. They were quantified in methanolic and aqueous crude extracts using HPLC. Highest amounts were obtained for extracts sequentially prepared under reflux of methanol, then aqueous-methanol. The concentrations found, respectively, ranged from 0.51 to 1.68 mg (g dw⁻¹) for CAF and 0.94–5.26 mg (g dw⁻¹) for CA (of plant dry mass g dw)⁻¹. This is the first report of CAF in a seagrass and CA in S. filiforme. Considering the demonstrated therapeutic applications of CA, its high value-added on the nutraceutical market, and its rare occurrence in the plant kingdom, the significant content found in S. filiforme leaves makes this abundant renewable raw material of interest for the pharmaceutical and food industries.     

Simultaneous quantification of caffeoyl esters and flavonoids in wild and cultivated cardoon leaves

Cynara cardunculus is a diploid (2n = 2x = 34) species, native to the Mediterranean basin, which belongs to the family of Asteraceae. It includes globe artichoke, cultivated cardoon, as well as their progenitor wild cardoon. The species is a source of biophenols and its leaf extracts have been widely used in herbal medicine as hepatoprotectors and choleretics since ancient times. Globe artichoke leaves have been found to be rich in compounds originating from the metabolism of phenylpropanoids however, to our knowledge, the leaf polyphenolic composition of the two other forms within the species, cultivated and wild cardoon, have not yet been properly investigated. Two main classes of polyphenols have been detected by HPLC/DAD and HPLC/MS analyses: caffeoyl esters and flavonoids. The compounds which are the result of esterification of caffeoylquinic acid moiety with succinic acid, previously detected in other members of the Asteraceae family, were detected in cardoon leaves for the first time.     

Caffeic acid derivatives in dried Lamiaceae and Echinacea purpurea products

The concentrations of caffeic acid derivatives within Lamiaceae and Echinacea (herb, spice, tea, and dietary supplement forms) readily available in the US marketplace (n = 72) were determined. After the first identification of chicoric acid in Ocimum basilicum (basil), the extent to which chicoric acid could be found within the family Lamiaceae was investigated. The dominant phenolic acid in all Lamiaceae samples was rosmarinic acid, which ranged from 2.04 mg/100 g (one of 12 oregano samples) to 622.28 mg/100 g (lemon balm). Of the herbs tested in this study (marjoram, oregano, peppermint, rosemary, sage, spearmint, and thyme from the family Lamiaceae), only basil and lemon balm (Melissa officinalis) contained chicoric acid. Basil samples (starting material and resulting end product) obtained from an industry cooperator, showed substantial phenolic deficiency as a result of processing (approximately 78% loss).     

Characterisation of phenolic antioxidants in aqueous extract of Orthosiphon grandiflorus tea by LC–ESI-MS/MS coupled to DPPH assay

Aqueous extract from Orthosiphon grandiflorus tea was on-line screened for its antioxidant components based on their capacity to scavenge free DPPH (1,1-diphenyl-2-picrylhydrazyl) radical after separation by a LC gradient. The structural elucidation of the active compounds was achieved by negative ionisation LC–ESI-MS/MS. Based on their mass spectra and fragmentation patterns related to antioxidant activity trace, seven compounds showing strong DPPH scavenging were identified to be danshensu, caffeic acid, caftaric acid, rosmarinic acid, caffeic acid derivative, sagerinic acid and salvianolic acid B. It is noted that danshensu, caftaric acid, sagerinic acid and salvianolic acid B have been reported in O. grandiflorus for the first time. In addition, the quantification of antioxidant compounds was performed using LC–MS/MS in multiple reaction monitoring (MRM) mode. Rosmarinic acid was found as a major component responsible for the antioxidant activity of this plant extract.     

HPLC/DAD/MS characterisation and analysis of flavonoids and cynnamoil derivatives in four Nigerian green-leafy vegetables

The present study sought to carry out a screening of the phenolic fraction of four Nigerian plants, Ocimum gratissimum L. (Og), Vernonia amygdalina L. (Va), Corchorus olitorius L., (Co) and Manihot utilissima Pohl. (Mu) consumed as food at least once daily by people in southwestern Nigeria and also used for medicinal purposes by local populations. HPLC/DAD and HPLC/ESI/MS analyses were applied as the most suitable techniques to investigate the phenolic content of the dried leaves. This screening allowed detection of up to 17 constituents in Va, five phenols in Mu, eight and 11 different metabolites in Co and Og, respectively. Some compounds have been detected for the first time in these vegetables: cichoric acid in Og, amentoflavone in Mu and several dicaffeoyl compounds in Va and Co. The study of the decoction demonstrated that almost all the phenolic constituents are stable even after a strong heating process such as boiling, as usually applied by Nigerian people prior to the consumption of these vegetables.     

Activity-guided isolation and identification of free radical-scavenging components from an aqueous extract of Coleus aromaticus

An activity-directed fractionation and purification process was used to identify the DPPH (l,l-diphenyl-2-picrylhydrazyl) free radical-scavenging components of Coleus aromaticus Benth. Fresh leaves of C. aromaticus were extracted with water and then separated into hexane, ethyl acetate, and water fractions. Among these, only the ethyl acetate phase showed strong DPPH radical-scavenging activity in vitro, when compared with water and hexane phases. The ethyl acetate fraction was then subjected to separation and purification using Sephadex LH-20 chromatography. Three compounds showing strong DPPH radical-scavenging activity were shown, by spectral methods (¹H NMR, ¹³C NMR, and MS) and by comparison with literature values, to be rosmarinic acid, chlorogenic acid and caffeic acid. In addition, HPLC identification and quantification of isolated compounds were also performed. Rosmarinic acid was found as a major component and principally responsible for the radical-scavenging activity of C. aromaticus.     

Phenolic profiles of cultivated, in vitro cultured and commercial samples of Melissa officinalis L. infusions

Melissa officinalis L. (lemon balm) is normally consumed as an infusion and presents therapeutic properties, such as sedative, carminative and antispasmodic, also being included in some pharmaceutical preparations. The phenolic profiles of different samples of lemon balm, prepared as infusions, were evaluated by HPLC-DAD-ESI/MS. The profiles were compared in order to understand the differences between cultivated, in vitro cultured and commercial (bags and granulated) samples. All the samples showed a similar phenolic profile, presenting differences only in the quantities found of each compound. Rosmarinic acid was the most abundant compound, being higher in commercial samples, especially in tea bag sample (55.68 mg/g of infusion) and lower in in vitro cultured sample (15.46 mg/g). Moreover, dimers, trimers and tetramers of caffeic acid were identified and quantified for the first time in lemon balm. Only one flavonoid, luteolin-3′-O-glucuronide was found in all the samples, ranging from 8.43 mg/g in commercial granulate sample to 1.22 mg/g in in vitro cultured sample. Overall, cultivated and in vitro cultured samples presented the lowest amounts of phenolic compounds (59.59 and 30.21 mg/g, respectively); otherwise, commercial samples showed the highest contents (109.24 mg/g for tea bag and 101.03 mg/g for granulate sample). The present study shows that infusion of lemon balm can be a source of phenolic compounds, known for their bioactive effects.     

How much do cultivar and preparation time influence on phenolics content in walnut liqueur?

The influence of cultivar and picking date on the phenolic content of walnut liqueur was investigated using HPLC with a PDA detector. Ten phenolic compounds, namely gallic, protocatechuic, ellagic, chlorogenic (5-caffeoylquinic), syringic, p-coumaric and sinapic acids, as well as (+)-catechin, 1,4-naphthoquinone and juglone were detected. The walnut liqueur under analysis was made of the cultivars ‘Franquette’ and ‘Elit’, on two sampling dates (June 30th and July 7th). A close interaction between cultivar and sampling date was noticed for most of the phenolics analyzed. The content levels of the main phenolic compounds under investigation were highest in ‘Franquette’ at the end of June and lowest in ‘Elit’ on the second or both sampling dates, except for syringic acid. A strong influence of cultivar choice and picking date was observed. The content levels of most phenolics were higher in liqueur prepared from the cultivar ‘Franquette’, than in ‘Elit’.     

Antioxidative properties and phytochemical composition of Ballota nigra infusion

The ability of Ballota nigra (Lamiaceae) infusion to act as a scavenger of DPPH radical, reactive oxygen species (superoxide radical, hydroxyl radical, hypochlorous acid) and nitric oxide was investigated. The tested infusion mainly exhibited a potent scavenging effect on DPPH, nitric oxide and superoxide radicals. In hydroxyl radical assay a potent pro-oxidant activity was noticed. No effect was found against hypochlorous acid. A phytochemical study was also undertaken, and seven phenolic compounds (chlorogenic, caffeic and caffeoylmalic acids, ballotetroside, forsythoside B, verbascoside and allysonoside) and eight organic acids (oxalic, aconitic, citric, ascorbic, malic, quinic, shikimic and fumaric acids) were identified and quantified by HPLC/DAD and HPLC/UV, respectively. Forsythoside B and quinic acid were revealed to be the main compounds in this infusion.     

Effect of nitrogen starvation on the phenolic metabolism and antioxidant properties of yarrow (Achillea collina Becker ex Rchb.)

In this study, the effects of long-term nitrogen deficiency (N 0.1 mM for 4 months) on growth, phenolic content and activity of phenylalanine ammonia lyase (PAL; EC 4.3.1.5) were investigated in the leaves, inflorescences and roots of yarrow (Achillea collina Becker ex Rchb.) grown in hydroponics. The antioxidant capacity of methanol extracts was also evaluated. Nitrogen starvation decreased plant growth and the leaves’ total nitrogen, amino acids, proteins, chlorophylls and carotenoids contents indicating that the primary metabolism was severely limited by low nitrogen availability. The amount of total phenolics and the antioxidant capacity were higher in leaves and roots of nitrogen-starved compared to control plants. The most abundant phenolic acids identified in yarrow were 5-O-caffeoylquinic acid (chlorogenic acid), and 3,5 and 4,5-di-O-caffeoylquinic acids. Nitrogen starvation significantly increased the contents of all these compounds and the PAL activity in leaf and root tissues. Results suggest that hydroponics, with proper manipulation of nutritional factors, might be a suitable system for the production of compounds with health benefits, such as caffeic acid derivatives, in yarrow.     

Nutritional components and anti-oxidant capacity of ten cultivars and lines of cactus pear fruit (Opuntia spp.)

Cactus pear fruit (Opuntia) are harvested from various species of the genus Opuntia of the cactus family (Cactaceae), and are produced and consumed in several countries. We have characterized the nutritional content and antioxidant capacity (AC) of the fruit of ten cultivars/lines of distinct pulp colors. ‘Camuesa’ had the highest betalains, total carotenoids, ß-carotene, ascorbic acid, and was one of the highest in total phenolic compounds, but its AC did not demonstrate outstanding differences with some other cultivars/lines that were not as rich in these compounds. ‘Roja Pelota’ had high AC when measured with the DPPH assay, but had low total carotenoids, ß-carotene and total phenolic content. ‘Reyna’ had slightly low AC as measured by the FRAP assay, practically no betalains, and low vitamin C, tocopherols, ß-carotene, and total phenolic content.     

Herbal infusions bioelectrochemical polyphenolic index: Green tea – The gallic acid interference

An amperometric biosensor containing immobilised laccase from Trametes versicolor was used for the quantification of phenolic compounds in herbal infusions and green tea samples, from nine botanical families. The main purpose of this research was to correlate the bioelectrochemical polyphenolic index (BPI) of the samples with the total phenolic content according to the Folin–Ciocalteu spectrophotometric method (TPC), and the total antioxidant activity (TAA) measured by TEAC (Trolox Equivalent Antioxidant Capacity). A strong correlation between BPI, TPC, and TAA was obtained for 10 herbal infusion samples. However, when a green tea sample was taken into account, a decrease in the linear correlation coefficient (r²) from 0.9949 to 0.2599 and 0.5609 to 0.1086 for the relationship between BPI/TPC and BPI/TAA, respectively, was observed. Thus, we could conclude that the green tea’s matrix affects the laccase-based biosensor response. HPLC–DAD analysis showed the presence of gallic acid only in the green tea sample. The results have indicated that gallic acid inhibited the laccase activity regarding the ABTS oxidation in a concentration-dependent manner. The very strong correlation between BPI/TPC obtained for herbal infusions allow us to conclude that the laccase-based biosensor, used in this research, provides a valuable tool to obtain a valid estimation of the classical Folin–Ciocalteu index, in an uncomplicated and fast way.     

Distribution of caffeic acid derivatives in Gundelia tournefortii L.

The caffeic acid derivatives including neochlorogenic acid (3-COA), cryptochlorogenic acid (4-CQA), chlorogenic acid (5-CQA) and caffeic acid (CA) have been characterised in Gundelia tournefortii using reference compounds, chemical, spectral evidences and chromatographic data. In addition, the total phenolic content and chlorogenic acid were measured in the leaf, hull-less seed, and skin extracts of this herb by the Folin–Ciocalteu reagent and high performance liquid chromatography (HPLC), respectively. The sample analysis was carried out on a C₁₈ column with 5% (v/v) aqueous acetic acid and methanol as the mobile phase, under gradient elution at ambient temperature, at 325 nm. The amount of chlorogenic acid in the leafs (at the flowering stage and after it) and hull-less seed were 984, 466 and 199 mg per 100 g dry plant sample and the total phenolic content in their dry extract were 128.4, 103.8 and 76.3 μg/mg as CGA equivalent, respectively.