Izabela Fecka

Determination of polyphenolic compounds in commercial herbal drugs and spices from Lamiaceae: thyme, wild thyme and sweet marjoram by chromatographic techniques

HPLC and HPTLC methods were used for a qualitative and quantitative determination of luteolin-7-O-β-glucuronide, lithospermic acid, rosmarinic acid and mthyl rosmarinate, together with other known compounds, in commercial herbal drugs and spices from lamiaceous species: Thymi herba, Serpylli herba and Majoranae herba. The contents of analyzed compounds in the studied hydrophilic extracts, prepared form herbal sources, were established using a C18 column with acetonitrile-water-formic acid as a mobile phase. The HPLC method was validated for linearity, precision and accuracy. Luteolin-7-O-β-glucuronide and lithospermic acid were identified as new wild thyme constituents, luteolin-7-O-β-glucuronide and methyl rosmarinate as new compounds in sweet marjoram. Methyl rosmarinate was isolated for the first time from thyme. The investigated herbal drugs and spices provide polyphenols in high amounts, even up to 84.3mg per 1g of a dried herb.

Qualitative and quantitative determination of hydrolysable tannins and other polyphenols in herbal products from meadowsweet and dog rose.

INTRODUCTION Meadowsweet and dog rose are used as herbal medicines and foodstuffs. Their biological and pharmacological properties are mainly attributed to vitamins, flavonoids and tannins known to be effective antioxidants. OBJECTIVE To evaluate the distribution of hydrolysable tannins and other polyphenols in commercially available products of Filipendula ulmaria and Rosa canina. METHODOLOGY In order to evaluate the distribution of polyphenols, the isolation and structure elucidation of six ellagitannins (tellimagrandins I and II, rugosins A, B, D and E) along with other well-known compounds was performed. Further high-performance chromatographic methods (HPLC, HPTLC) were developed for qualitative and quantitative studies of phenolic acids, flavonoids and tannins in meadowsweet flowers and dog rose fruits. The analysis of linearity, limits of detection and quantification, precision and accuracy showed that the HPLC assay was sufficiently precise for content evaluation. Selection of a suitable solvent and optimisation of the sample extraction procedure were also carried out. RESULTS Amounts of more than 20 polyphenols were estimated in the studied pharmaceuticals (27 products of meadowsweet and 10 products of dog rose) using a Chromolith Performance RP-18e column and UV detection. Methyl gallate 3-O-beta-glucoside was identified for the first time in dog rose, while rugosins A, B and E are new meadowsweet constituents. CONCLUSION The results showed that meadowsweet flowers and rose hips with seeds yielded 55.53-124.8 and 0.43-1.26 mg/g of ellagitannins, respectively. The sum of detected polyphenols was 83.88-165.68 mg/g for Filipendulae ulmariae flos and 1.21-2.66 mg/g for Rosae pseudo-fructus cum fructibus.

Antiradical and anti-H2O2 properties of polyphenolic compounds from an aqueous peppermint extract.

Polyphenolic compounds such as eriocitrin, luteolin-7-O-rutinoside, diosmin, hesperidin, narirutin, isorhoifolin, rosmarinic and caffeic acids were identified in an aqueous extract (Ex) obtained from peppermint leaves (Menthae × piperitae folium). The content of polyphenols in Ex was as follows: eriocitrin 38%, luteolin-7-O-rutinoside 3.5%, hesperidin 2.9%, diosmin 0.8%, isorhoifolin 0.6%, narirutin 0.3%, rosmarinic acid 3.7% and caffeic acid 0.05%. The strongest antiradical activity (determined as DPPH• scavenging features) was observed for luteolin-7-O-rutinoside, eriocitrin and rosmarinic acid. Caffeic acid and hesperidin revealed a lower antiradical activity while isorhoifolin, narirutin and diosmin showed the lowest activity. The strongest anti-H2O2 activity was observed for eriocitrin, a little lower for rosmarinic acid. The rate of hydrogen peroxide scavenging activity displayed by luteolin-7-O-rutinoside and caffeic acid was lower than that of rosmarinic acids. Hesperidin appeared to be a very weak scavenger of hydrogen peroxide. Almost no anti-H2O2 activity was demonstrated for diosmin, narirutin and isorhoifolin. Among examined flavonoids, the strongest antiradical and anti-H2O2 activity was shown for compounds with two hydroxy groups bound to the Bring in ortho position in relation to each other. Replacement of one hydroxy group in the Bring with a methoxy group or removing one hydroxy group leads to decrease of antiradical and anti-H2O2 activity of flavonoids. Our results suggest that eriocitrin is a powerful peppermint antioxidant and a free radical scavenger.

TLC determination of tannins and flavonoids in extracts from some Erodium species using chemically modified stationary phases

Natural phenolic compounds, e.g. ellagitannins, gallotannins, and flavonoid glycosides, from the aerial parts of Erodium cicutarium (Geraniaceae) have been isolated and identified. The structures of these compounds were determined by conventional methods of analysis and confirmed by MS and NMR spectral analysis. The distribution of tannins and flavonoids in E. ciconium, E. cicutarium, E. manescavi, and E. pelargoniiflorum were examined by TLC on unmodified silica gel and on silica gel chemically modified with polar and nonpolar groups (HPTLC Si 60, HPTLC Si 60 LiChros-pher, HPTLC diol, HPTLC CN, and HPTLC RP-18W).

HPLC analysis of polyphenols in the fruits of Rubus idaeus L. (Rosaceae).

The separation of anthocyanins present in the fruits of 11 varieties of red raspberries (Rubus idaeus L.) was performed by high performance liquid chromatography (HPLC) with a diode-array detector and evaporative light scattering detection (ELSD). The ELSD parameters – drift tube temperature, nebulising gas flow rate and gain value – were optimised to get the best detection and identification of the anthocyanins. The varieties Heritage and Willamette had the simplest anthocyanin sets consisting of only two predominant anthocyanins – cyanidin-3-O-sophoroside (1) and cyanidin-3-O-glucoside (3), while in the other varieties two other predominant compounds were also present, cyanidin-3-O-rutinoside (4) and cyanidin-3-O-(2G-O-glucosylrutinoside) (2). Moreover, using ELSD, simultaneous analysis of anthocyanins and sanguiin H-6 (5), an ellagitannin, was performed. The contents of anthocyanins and sanguiin H-6 (5) were estimated by HPLC with ultraviolet-visible (UV-vis) light detection. The determined concentrations of anthocyanins varied from 76.22 to 277.06 mg per 100 g of dry weight (d.w.). The content of sanguiin H-6 (5) was in the range from 135.04 to 547.48 mg per 100 g of d.w.

Optimization of the separation of flavonoid glycosides and rosmarinic acid from Mentha piperita on HPTLC plates

Caffeetannins and flavonoid glycosides have been analyzed in polar solvent extracts from leaves of Mentha piperita (Lamiaceae). Peppermint extracts and individual compounds isolated from the leaves were investigated by TLC with horizontal development on unmodified silica gel (HPTLC Si 60, HPTLC LiChrospher Si 60) and on silica gel chemically modified with polar (HPTLC NH2, HPTLC CN) and non-polar groups (HPTLC RP-18W). The mobile phase acetone—acetic acid, 85 + 15 (v/v), enabled successful separation on the aminopropyl adsorbent; water—methanol, 60 + 40 (v/v), was best on the octadecyl adsorbent. These simple methods can be very useful for rapid estimation of components of peppermint leaves or extracts.

Quantification of tannins and related polyphenols in commercial products of tormentil (Potentilla tormentilla)

INTRODUCTION Potentilla tormentilla has many biological and pharmacological properties and can be used as an ingredient of some herbal medicines or beverages. OBJECTIVE The aim of this study was to evaluate the content of individual polyphenols, especially condensed and hydrolysable tannins in commercially available tormentil rhizomes and tinctures using chromatographic methods. METHODS A quantitative analysis (HPLC-PDA) was preceded by qualitative studies (UPLC-qTOF-MS/MS) and the isolation (CC) of the major tannin compounds. RESULTS The tested plant material is characterised by a high content of tannins and related polyphenols, i.e. in rhizomes even at the level above 20% and in tinctures above 2%. The main components of tormentil rhizomes are procyanidin B3 (mean ~ 3.6%), procyanidin C2 (mean ~ 2.8%), agrimoniin (mean ~ 2.5%), 3-O-galloylquinic acid (mean ~ 1.7%), catechin (mean ~ 1.6%), other flavan-3-ol oligomers (mean ~ 0.5-1.1) and laevigatins (mean ~ 0.2-0.6%). Free ellagic acid and glycosides of ellagic and methylellagic acids are secondary components. CONCLUSIONS Underground parts of tormentil are a source of oligomeric proanthocyanidins and ellagitannins, but in smaller quantity of gallotannins. Monogalloylquinic acids are new identified compounds, which had not been described in Potentilla tormentilla before we started our research. In the analysed tormentil tinctures agrimoniin concentration is lower in relation to other tannins.

Characterization of Phenolic Compounds of Thorny and Thornless Blackberries

The aim of this study was to identify and compare the contents of phenolic acids, tannins, anthocyanins, and flavonoid glycosides in thorny and thornless blackberries. Five thorny and nine thornless cultivars were used for this study. Thirty-five phenolic compounds were determined in the examined fruits, and one phenolic acid, three ellagic acid derivatives, one anthocyanin, and six flavonols were characterized for the first time in blackberries. The thornless fruits were characterized by a higher content of anthocyanins (mean = 171.23 mg/100 g FW), ellagitannins (mean = 3.65 mg/100 g FW), and ellagic acid derivatives (mean = 2.49 mg/100 g FW), in comparison to thorny ones. At the same time, in thorny fruits, the contents of hydroxycinnamic acids (mean = 1.42 mg/100 g FW) and flavonols (mean = 5.70 mg/100 g FW) were higher.

Iridoids, Phenolic Compounds and Antioxidant Activity of Edible Honeysuckle Berries (Lonicera caerulea var. kamtschatica Sevast.)

Iridoid and polyphenol profiles of 30 different honeysuckle berry cultivars and genotypes were studied. Compounds were identified by ultra-performance liquid chromatography coupled with electrospray ionization mass spectrometry (UPLC-ESI-qTOF-MS/MS) in positive and negative ion modes and quantified by HPLC-PDA. The 50 identified compounds included 15 iridoids, 6 anthocyanins, 9 flavonols, 2 flavanonols (dihydroflavonols), 5 flavones, 6 flavan-3-ols, and 7 phenolic acids. 8-epi-Loganic acid, pentosyl-loganic acid, taxifolin 7-O-dihexoside, and taxifolin 7-O-hexoside were identified in honeysuckle berries for the first time. Iridoids and anthocyanins were the major groups of bioactive compounds of honeysuckle constituents. The total content of quantified iridoids and anthocyanins was between 128.42 mg/100 g fresh weight (fw) (‘Dlinnoplodnaya’) and 372 mg/100 g fw (‘Kuvshinovidnaya’) and between 150.04 mg/100 g fw (‘Karina’) and 653.95 mg/100 g fw (‘Amur’), respectively. Among iridoids, loganic acid was the dominant compound, and it represented between 22% and 73% of the total amount of quantified iridoids in honeysuckle berry. A very strong correlation was observed between the antioxidant potential and the quantity of anthocyanins. High content of iridoids in honeysuckle berries can complement antioxidant properties of phenolic compounds.

Tannins and Flavonoids from the Erodium cicutarium Herb

A new depside, erodiol, was isolated and identified from the aerial parts of Erodium cicutarium (Geraniaceae), together with essential compounds such as: geraniin, didehydrogeraniin, corilagin, (-) 3-O-galloylshikimic acid, methyl gallate 3-O-β -D-glucopyranoside, rutin, hyperin, quercetin 3- O-(6”-O-galloyl)-β -D-galactopyranoside, isoquercitrin and simple phenolic acids. Their chemical structures were elucidated by means of spectroscopic (ESI MS, HRESI MS, 1D and 2D NMR) evidence.