Analysis of amino acids content in the plant components of the antidiabetic herbal mixture by GC-MS

Magnetic Titanium Dioxide Nanocomposites as a Recyclable SERRS Substrate for the Ultrasensitive Detection of Histidine

A highly sensitive, selective and recyclable histidine detection method based on magnetic Fe3O4@mTiO2 (M-TiO2) nanocomposites with SERRS was developed. Mesoporous M-TiO2 nanoparticles were functionalized with 4-aminothiophenol and then coupled with histidine through an azo coupling reaction in 5 min, producing the corresponding azo compound. The strong and specific SERRS response of the azo product allowed for ultrasensitive and selective detection for histidine with an M-TiO2 device loaded with Ag NPs due to the molecular resonance effect and plasmonic effect of Ag NPs under a 532 nm excitation laser. The sensitivity was further enhanced with the magnetic enrichment of M-TiO2. The limit of detection (LOD) was as low as 8.00 × 10-12 mol/L. The M-TiO2 demonstrated applicability towards histidine determination in human urine without any sample pretreatment. Additionally, the M-TiO2 device can be recycled for 3 cycles with the photodegradation of the azo product under UV irradiation due to TiO2-assisted and plasmon-enhanced photocatalysis. In summary, a multifunctional and recyclable M-TiO2 device was synthesized based on azo coupling and SERRS spectroscopy for ultra-sensitive and specific histidine sensing. In addition, the proposed system demonstrated the potential for the multiplex determination of toxic compounds in the fields of food safety, industrial production and environmental protection, which benefit from the fingerprint property and universality of SERRS.

An Updated Systematic Review of Vaccinium myrtillus Leaves: Phytochemistry and Pharmacology

Bilberry leaves are used in many countries in traditional medicine for treating a wide variety of diseases. Due to the high therapeutic potential of Vaccinium myrtillus (VM) leaves, this review aims to present the latest knowledge on the phytochemical profile, as well as the therapeutic effects of this herbal drug. The review was conducted according to the Prisma guidelines, and the scientific databases were searched using combinations of the following keywords: "Vaccinium myrtillus", "leaves", "bilberry". Recent research was focused on the influence of abiotic factors on the phytochemical composition, and it seems that there are significant differences between the herbal drugs collected from different countries. The phytochemical composition is correlated with the broad spectrum of pharmacological effects. The paper outlines the potent antimicrobial activity of VM extracts against multidrug-resistant bacterial strains, and also the pathways that are modulated by the unique "cocktail" of phytoconstituents in different metabolic alterations. Reviewing the research articles published in the last 10 years, it seems that bilberry leaves have been slightly forgotten, although their phytochemical and pharmacological characteristics are unique.

HPLC-DAD assay of flavonoids and evaluation of antioxidant activity of some herbal mixtures

Medicinal plants and their combinations can influence various links of the pathogenetic mechanism of diabetes mellitus type 2 and its complications, due to the wide range of biologically active substance that they accumulate. Flavonoids deserve particular attention through their antioxidant properties. Three samples of herbal mixtures (sample 1 – Inula helenium rhizome with roots, Helichrysum arenarium flowers, Zea mays columns with stigmas, Origanum vulgare herb, Rosa majalis fruits, Taraxacum officinale roots; sample 2 – Cichorium intybus roots, Elymus repens rhizome, Helichrysum arenarium flowers, Rosa smajalis fruits, Zea mays columns with stigmas; sample 3 – Urtica dioica leaf, Taraxacum officinale roots, Vaccinium myrtillus leaf, Rosa majalis fruits, Mentha x Menthapiperita herb) were tested for flavonoid content and antioxidant properties.

Using HPLC-DAD analysis the content of flavonoids was evaluated and an antioxidant activity by DPPH-radicals scavenging, ferrous ion chelating capacity and ferric reducing power were established for the herbal mixtures. Rutin prevails in sample 3, its content was 2745.66±0.21 μg/g; luteolin – in samples 1 and 2, its content was 371.31±0.07 μg/g and 313.48±0.13 μg/g, respectively.

Flavonoids attribute to the antioxidant activity of the herbal mixtures, which was confirmed by DPPH radical scavenging assay, ferric reducing power assay and ferrous ion chelating assay. The highest antioxidant capacity was found for sample 3 – IC50 of inhibition of DPPH radicals was 301.65±2.67 µg/mL compared to control – ascorbic acid (119.24±2.35 µg/mL), the ferric reducing power was 0.382 at 100 µg/mL compared to ascorbic acid (0.412 at 100 µg/mL) and IC50 of chelating capacity was 206.59±2.48 µg/mL compared to EDTA-Na2 (110.55±1.93 µg/mL).

HPLC-DAD assay of phenols profile in Antennaria dioica (L.) Gaertn

Antennaria dioica (Asteraceae family) – is a perennial herb, commonly found in dry grasslands and sandy or stony places from Eurasian areas. It is known in traditional medicine as antioxidant, diuretic, choleretic and anti-inflammatory remedy. This species should be reconsidered as possible sources of phenols, mainly flavonoids and hydroxycinnamic acids. Thus, the aim of this study was to validate a chromatographic method for detection of phenols and their identification in A. dioica herb. HPLC-DAD method was evaluated in terms of linearity, precision, repeatability, accuracy, LOD and LOQ. The calibration curves of thirteen reference substances were linear (R2 > 0.99) over the range of 5–400 µg/mL, the LODs and the LOQs were in the range of 0.1–0.3 µg/mL and 0.2–1.0 µg/mL, respectively. During HPLC-DAD assay two flavones – luteolin, apigenin; flavonol – quercetin and three its glycosides – rutin, hyperoside and isoquercitrin; coumarins: coumarin and umbelliferone; five hydroxycinnamic acids – chlorogenic, caffeic, p-coumaric, trans-ferulic and rosmarinic were identified in A. dioica herb. This phytochemical study of A. dioica confirms that this plant material is a rich source of phenolic compounds.

HPLC-FLD analysis of amino acids content in Chrysanthemum morifolium

Chrysanthemum morifolium (Asteraceae family) have long been used as a tonic, antioxidant, antipyretic, analgesic, sedative, antitumor, neuroprotector, hepatoprotector and cardioprotector agent. This species should be reconsidered as possible sources of many biocompounds, especially amino acids. Thus, the aim of this study was to validate the chromatographic method for detection of amino acids and their identification in flowers and leaves of Ch. morifolium of variant Pectoral. HPLC-FLD method was evaluated in terms of linearity, precision, repeatability, accuracy, LOD and LOQ. The calibration curves of all analytical standards of amino acids were linear (R2 > 0.99) over the range of 0.015–0.625 μmol/mL, the LODs and the LOQs were in the range of 0.001–0.096 µg/mL and 0.004–0.321 µg/mL, respectively. During the HPLC-FLD assay ten amino acids in free form and fifteen amino acids after hydrolysis in Ch. morifolium flowers were identified. Besides, twelve amino acids were detected in free form and fourteen amino acids after hydrolysis in Ch. morifolium leaves. The results of HPLC-FLD analysis showed that the predominant amino acid was L-proline in both types of herbal raw materials. Its total content was 31.67±0.02 μg/mg in Ch. morifolium flowers and 18.56±0.02 μg/mg in Ch. morifolium leaves. This phytochemical study confirms that flowers and leaves of Ch. morifolium (Pectoral) are rich sources of amino acids and can exhibit a wide range of pharmacological activities.