Assessment of pharmaceutically important phenolic compounds in fungal crude extracts of native endophytes

Optimization of microwave-assisted extraction of phenolic compounds from tomato: Characterization by FTIR and HPLC and comparison with conventional solvent extraction

The genus Dragonhead (Dracocephalum L.) includes 72 species of essential oil-bearing plants belonging to the Lamiaceae family. Many of them have long been used in a folk medicine of different countries. Moldavian dragonhead (D. moldavica L.) has been identified as the most promising species for the complex phytochemical research since it was successfully introduced in the climatic conditions of the Ukrainian forest-steppe zone and due to the presence of its various botanical forms and varieties. The aim of this study was the phytochemical analysis of the main groups of secondary metabolites in the herb of violet-flowered form of Moldavian dragonhead (D. moldavica L.) under its cultivation in Ternopil region (Ukraine). The herb of the plant was harvested in July of 2018‒2019 years during the flowering period. The essential oil was obtained from the plant raw material by the hydrodistillation. Such physical and chemical parameters of the essential oil as a relative density, refractive index, optical rotation, acid number and solubility in ethanol were studied. The method of thin layer chromatography (TLC) was used to determine the specific sequence of bands in the chromatograms of essential oil. The method of high-performance thin-layer chromatography (HPTLC) was used for the identification of phenolic compounds in the herb. The component composition of polyphenols was determined by the high performance liquid chromatography (HPLC). The specific physical and chemical parameters as well as the «chromatographic profile» of essential oil have been established. The main compounds of the polyphenolic nature were revealed by the chromatographic methods. In particular, rosmarinic and caffeic hydroxycinnamic acids were identified in the methanol extract of herb by the HPTLC method. The HPLC analysis of phenolic compounds in the 70% ethanol extract of raw material established that rosmarinic acid was its main polyphenol. It was found the decreasing of polyphenol contents in the D. moldavica herb in such direction: rosmarinic acid (3.01%) > apigenin-7-О-glucoside (0.67%) > apigenin (0.29%) > caffeic acid (0.28%) > luteolin-7-О-glucoside (0.13%)> hyperoside (0.12%) > ferulic acid (0.09%) > chlorogenic acid (0.08%). The obtained data could be used for planning pharmacological studies of the phytosubstances developed from the Moldavian dragonhead herb.

Lepidium sativum L. (Brassicaceae), garden cress or pepper grass, is the source of valuable biologically active compounds [1]. It is used in folk medicine for cancer, uterine tumors, polyps, and other neoplasms. It is used in medicine as the alcoholic tincture, which possesses sedative and anticonvulsive activity [2]. Herein we communicate results from investigations of phenolic compounds isolated from L. sativum seeds grown in culture by us. Ground air-dried raw material (seeds, 1.0 g) was extracted successively with hexane, CCl4, and CHCl3 (20 mL each), discarding the produced extracts. Then, the remaining raw material was extracted with boiling ethanol (70%) for 1 h. The extract was cooled, filtered through paper into a volumetric flask (100-mL), and adjusted to the mark with ethanol (70%). The resulting extract (2 mL) was placed into a volumetric flask (25-mL) and adjusted with the same solvent to the mark (stock solution). A series of reference solutions in ethanol (70%) was prepared in parallel. These included rutin, quercetin, luteolin, luteolin-7-glycoside, hyperoside, hesperidin, apigenin, vicenin, vitexin, 4-hydroxycoumarin, scopoletin, robinin, dicoumarin, coumarin, umbelliferone, dihydroquercetin, catechin, orientin, and gallic, chlorogenic, neochlorogenic, cinnamic, caffeic, ferulic, salicylic, and ellagic acids. The stock and reference solutions (20 μL) were injected into a chromatograph. The qualitative composition of the phenolic compounds from L. sativum seeds was studied on a Gilston Model 305 (France) high-performance liquid chromatograph (HPLC) with a Rheodyne 7125 (USA) manual injector with subsequent computer processing of the results using the program Multichrom for Windows. The mobile phase was CH3OH:H2O:H3PO4 (400:600:5). The analysis was performed at room temperature. The eluent flow rate was 0.5 mL/min; analysis time, 120 min. Detection used a Gilston Model 151 UV/Vis UV detector operating at 254 nm. A total of 12 compounds was isolated by the HPLC analysis of L. sativum seeds. Of these, gallic acid (9.44%, content in the isolated mixture by internal normalization method), chlorogenic acid (14.77%), ferulic acid (5.63%), neochlorogenic acid (2.22%), luteolin-7-glycoside (14.67%), dihydroquercetin (4.37%), and quercetin (3.15%) were identified. Quantitative analysis of phenolic compounds from L. sativum seeds was based on the UV absorption spectra of this group of compounds. The absorption spectra were defined using the extract (70% ethanol) of seeds and a Helios (USA) selfrecording spectrophotometer in the wavelength range 210-400 nm. According to preliminary results on the identification by HPLC of phenolic compounds from L. sativum seeds, chlorogenic acid was the predominant component. Therefore, the absorption spectrum of chlorogenic acid in ethanol (70%) was recorded in parallel as a working standard in the same wavelength range. Absorption spectra of the studied solution and the chlorogenic acid solution had a common absorption maximum at 329 ± 2 nm. This enabled us to calculate the total phenolic compounds in L. sativum seeds using chlorogenic acid as a working standard. The studied solution was prepared by the method given above (weight 1.0 g). The working standard (chlorogenic acid, 0.02 g) was placed in a volumetric flask (50-mL), treated with ethanol (70%, 30 mL), stirred until dissolved, and adjusted to the mark (solution A). Solution A (1 mL) was placed in a volumetric flask (50-mL) and adjusted with the same solvent to the mark (working standard). The optical density of the resulting solutions was measured at 329 nm relative to ethanol (70%). The contents of total phenolic compounds calculated as chlorogenic acid in L. sativum seeds was 0.85%.

The aim of this paper was to determine the effect of the hydrolysis method on the amounts of phenolic compounds in the plant material in soil and, as a consequence, on the parameters to determine the degree of lignins transformation in soils. The study included the plant material (hay, sward, and roots) and soil—Albic Brunic Arenosol (horizon A, AE, and Bsv) samples. Phenolic compounds were isolated at two stages by applying acid hydrolysis followed by alkaline re-hydrolysis. The quantitative and qualitative analysis of phenolic compounds was performed with high-performance liquid chromatography with a DAD. The content of phenolic compounds in the extracts depended on the hydrolysis method and it was determined by the type of the research material. The amounts of phenolic compounds contained in the alkaline hydrolysates accounted for 55.7% (soil, horizon Bsv)—454% (roots) of their content in acid hydrolysates. In the extracts from acid hydrolysates, chlorogenic and p-hydroxybenzoic acids were dominant. In the alkaline extracts from the plant material, the highest content was recorded for p-coumaric and ferulic acids, and in the extracts from soil, ferulic and chlorogenic acids. A combination of acid and alkaline hydrolysis ensures the best extraction efficiency of insoluble-bound forms of polyphenols from plant and soil material.

The enrichment of fruit juices with concentrated polyphenolic extracts is an expedient strategy to compensate possible phenolic loss through gastrointestinal processing. Pycnogenol, a standardised procyanidin-rich extract from pine bark, has been proposed as a potential candidate for polyphenol enrichment of foods. In this study the effects of in vitro digestion on the phenolic profile of fruit juices enriched with Pycnogenol were investigated. After in vitro digestion the level of detectable total phenolic compounds (expressed as gallic acid equivalent) was higher in both pineapple and red fruit juices enriched with Pycnogenol than in non-enriched commercial juices. Five phenolic monomeric compounds were identified by high-performance liquid chromatography, namely chlorogenic acid, caffeic acid, ferulic acid, gallic acid and taxifolin, the last two being predominant. In vitro digestion of both Pycnogenol-enriched pineapple and red fruit juices led to a significant (P < 0.05) increase in detectable chlorogenic and ferulic acids, indicating that hydrolysis of more complex molecules occurs. On the other hand, in vitro digestion of non-enriched juices was associated with a decrease in gallic and caffeic acids in pineapple juice and with a decrease in ferulic acid in red fruit juice. In no case did in vitro digestion increase the amount of detectable phenolic compounds in non-enriched juices. The stability of Pycnogenol after in vitro gastrointestinal digestion makes it a good choice for phenolic enrichment of fruit juices.

Specifically, the extraction yield, the content of total polyphenols by Folin-Ciocalteu colorimetric assay, and the antioxidant activity by FRAP (Ferric Reducing Antioxidant Power) were measured. In particular the following specific phenolic compounds were detected and determined by HPLC analysis: gallic, chlorogenic, ferulic, p-coumaric, and ellagic acids, (+)-catechin, (–)-epicatechin, and rutin. The values of extraction yield and total polyphenol content decreased according to the extraction solvent in the following order: absolute methanol > 70% methanol > water. The antioxidant activity showed the opposite trend among the three types of extraction. The values obtained from the analysis were higher in chestnut rather than in hazelnut shell. The specific amount of phenolic compounds varied depending on the solvent used for the extraction. Gallic acid was found in all samples extracted, though with lower values in hazelnut shells treated in water. High values of (–)-epicatechin, chlorogenic acid and ellagic acid were found in hazelnut samples extracted with hydro-alcoholic solution and water. A fair amount of catechin was detected in all samples, whilst rutin, p-coumaric acid and ferulic acid were present in small amounts, although the best results were obtained in absolute methanol. The results of this study demonstrated that with a simple extraction process considerable amount of phenolic compounds with high antioxidant activity were obtained from chestnut and hazelnut shells.

The influence of a commercial production process for dehydrated potato flakes on the content of free phenolic compounds, total phenolics, and glycoalkaloids in potatoes during the subsequent processing steps was determined. Processing byproducts, such as potato peel (steam peeling), mashed potato residues, and side streams (blanching and cooking waters), have also been investigated. A high-performance liquid chromatography (HPLC) method was developed to separate and quantify caffeic acid, gallic acid, ferulic acid, p-coumaric acid, p-hydoxybenzoic acid, protocatechuic acid, vanillic acid, catechin, and three isomers of caffeoylquinic acid: chlorogenic, neochlorogenic and cryptochlorogenic acid. Determination of the glycoalkaloids alpha-solanine and alpha-chaconine was performed by using a high-performance thin-layer chromatography (HPTLC) method. The deliverables reveal that processing potatoes to potato flakes remarkably diminishes the content of the analyzed compounds, mainly due to peeling and leaching. The influence of thermal exposure is less significant. About 43% of the initial phenolic acids and 10% of the glycoalkaloids remain after processing. The results of the total phenolic content assay by Folin-Ciocalteu reagent are proportional to the content of phenolic compounds determined by HPLC. Steam peeling has a higher influence on glycoalkaloid losses compared to that on phenolics. The highest amounts of phenolic compounds and glycoalkaloids were found in peeling byproduct. During processing, the amount of chlorogenic acid decreased, whereas the concentration of neochlorogenic acid increased due to isomerization. The impact of the results on potato processing technology is discussed.

Chlorogenic acids (CGAs) are major polyphenols found in coffee that offer numerous health benefits. CGAs are compounds in which caffeic or ferulic acids are ester-bonded to quinic acids, with molecules such as caffeoylquinic acid, feruloylquinic acid, and dicaffeoylquinic acid being prominent examples. Due to their diverse structures, CGAs can be converted into multiple molecules during absorption, exerting various health effects through subtle differences in action. This chapter explores the health effects and mechanisms of CGAs, caffeic acid, and ferulic acid. In particular, it focuses on their impact on type 2 diabetes mellitus (T2DM), dyslipidemia, and hypertension associated with obesity, which form the basis of metabolic syndrome. Studies published in PubMed, ScienceDirect, and Web of Science on the health benefits of coffee, coffee-derived CGAs, quinic acid, and caffeic acid were analyzed. CGAs, quinic acids, and caffeic acids may potentially mitigate metabolic syndrome by preventing T2DM and various diseases, such as hypertension, through mechanisms including antioxidant activity.

Ferulic Acid Stabilizes a Solution of Vitamins C and E and Doubles its Photoprotection of Skin

Kola seeds are highly valued in most African communities due to their medicinal benefits and socio-cultural application during ceremonies. Apart from their neuro-stimulatory effect, the other health benefits such as antioxidant activities which are closely associated with the level of phenolic constituents have also been widely reported. The main purpose of this study is to determine the quantity of quercetin, caffeic acid, gallic acid, ferulic acid, rutin and chlorogenic acid in Cola nitida, Garcinia kola and Buchholzia coriacea using HPLC-DAD. Ethanolic extracts of the selected kola plants was obtained by cold maceration and analysed by HPLC-DAD in accordance with standard methods. The regression coefficient (r2) from the calibration curve for caffeic acid = 0.999, chlorogenic acid = 0.998, gallic acid = 0.999, ferulic acid = 0.998, quercetin = 0.996 and rutin = 0.997. The repeatability gave % RSD of 0.6, 1.63, 0.44, 1.55, 3.65 and 4.67 for caffeic acid, chlorogenic acid, gallic acid, ferulic acid, quercetin and rutin respectively. The quantity of these compounds in C. nitida was caffeic acid (101.24 mg/g), chlorogenic acid (36.35 mg/g), gallic acid (16.99 mg/g) ferulic acid (1.47 mg/g) while quercetin and rutin were not detected. In Garcinia kola, caffeic acid was (0.84 mg/g), gallic acid (1.02 mg/g), ferulic acid (21.83 mg/g), quercetin (53.24 mg/g), rutin (0.49 mg/g) and chlorogenic acid was not detected. B. coriaceae had caffeic acid (1.03 mg/g), chlorogenic acid (0.33 mg/g), gallic acid (1.07 mg/g) while ferulic acid, quercetin and rutin were not detected. Using this analytical method, the quantities of some phenolics and flavonoids compounds were determined, and the most abundant compound in the three species of kola was caffeic acid in C. nitida and quercetin in Garcinia kola. This study also showed that C. nitida contains high amounts of phenolics compounds as compare to the other species of kola seeds investigated in the study. Key word: Phenolic acids, flavonoids, high-performance liquid chromatography- diode-array detector (HPLC-DAD), Cola nitida, Garcinia cola, Buchholzia coriacea.

ABSTRACTFicus deltoidea Jack (Moraceae) is a well-known medicinal plant used in customary medication among the Malay people to reduce and mend sicknesses such as ulcers, psoriasis, cytotoxicity, cardioprotective, inflammation, jaundice, vitiligo, hemorrhage, diabetes, convulsion, hepatitis, dysentery injuries, wounds, and stiffness. Ficus deltoidea contains a wide variety of bioactive compounds from different phytochemical groups such as alkaloids, phenols, flavonoids, saponins, sterols, terpenes, carbohydrates, and proteins. The genus Ficus has several hundreds of species, which shows excellent therapeutic effects and a wide variety of helpful properties for human welfare. Searching information was collected by using electronic databases including Web of Science, Science Direct, Springer, SciFinder, PubMed, Scopus, Medline, Embase, and Google Scholar. This review is, therefore, an effort to give a detailed survey of the literature on its pharmacognosy, phytochemistry, phytochemical, and pharmacological properties of Ficus and its important species. This summary could be beneficial for future research aiming to exploit the therapeutic potential of Ficus and its useful medicinal species.

Ultrasonic-assisted deep eutectic solvent extraction and identification of phenolic compounds from Atractylodes chinensis adventitious root culture.

Hydroxycinnamic acids are antioxidant polyphenols common in the human diet, although their potential health benefits depend on their bioavailability. To study the hepatic uptake and metabolism, human hepatoma HepG2 cells were incubated for 2 and 18 h with caffeic, ferulic, and chlorogenic acids. Moderate uptake of caffeic and ferulic acids was observed versus a low absorption of chlorogenic acid, where esterification of the caffeic acid moiety markedly reduced its absorption. Methylation was the preferential pathway for caffeic acid metabolism, along with glucuronidation and sulfation, while ferulic acid generated glucuronides as the only metabolites. Ferulic acid appeared to be more slowly taken up and metabolized by HepG2 cells than caffeic acid, with 73% and 64% of the free, nonmetabolized molecules detected in the culture medium after 18 h, respectively. In conclusion, hydroxycinnamic acids can be metabolized by the liver as suggested by the results obtained using HepG2 cells as a hepatic model system.

Whole crop rice (WCR) is used as an important feed for livestock ruminants. In this study, “Yeongwoo” variety WCR (cultivated on the Korean peninsula) was harvested at three different maturity stages (booting, heading, and milk) and their phenolic acid and flavonoid profiles in the lactic acid bacteria (LAB)-inoculated and noninoculated silage, hay, and fresh freeze-dried WCR extract were quantified. The alterations in the phenolic and flavonoid contents of the selected WCR during maturation in different samples were analyzed by the High-Performance Liquid Chromatography- Diode Array Detector (HPLC–DAD) technique. The six phenolics (caffeic acid, ferulic acid, p-coumaric acid, chlorogenic acid, dihydroxy benzoic acid, and prophyl gallate) and six flavonoids (rutin hydroxide, luteolin, kaempferol, vitexin, myricetin, and quercetin) were noted to have slight differences between the LAB-inoculated and noninoculated silage samples; however, the phenolics and flavonoids were higher in hay WCR at the milk stage compared to the silage and fresh freeze-dried samples. The results indicate that WCR harvest times have different phenolic compounds in the WCR silage, hay, and fresh samples. The phenolic and flavonoid compounds were higher (p &lt; 0.05) with the increase in maturity (Stage 1–3). The stage of WCR maturity was positively related (p &lt; 0.05) to the amount of phenolic acid and flavonoid contents (µg/g) in hay, silage, and fresh freeze-dried extract. We observed the WCR had high amounts of phenolic acid and flavonoid concentrations at milk stage (Stage 3) hay (quercetin, kaemferol, luteolin, ferulic acid, caffeic acid, and coumaric acid were 1.28, 1.29, 0.54, 1.54, 1.92, and 1.81 µg/g, respectively) compared with the booting and heading stages (Stages 1 and 2), with acceptable accuracy on a pilot scale. Based on these results, it could be concluded that LAB (Lactobacillus plantarum)-inoculated whole crop rice silage (WCRS) did not affect the phenolics and flavonoids of secondary plant metabolites in fermented silage. However, phenolics and flavonoids were of higher rations in WCR at the milk stage. Furthermore, this phenolic acid and flavonoid effect needs to be confirmed using large-scale in vivo analysis.

The kinetics and mechanisms of reactions of iron(III) with caffeic acid, chlorogenic acid, sinapic acid, ferulic acid and naringin