Separation and free radical-scavenging activity of major curcuminoids of Curcuma longa using HPTLC-DPPH method

The potential of turmeric extract-loaded chitosan microparticles for the treatment of gastrointestinal disorders

AIM

To develop turmeric extract-loaded chitosan microparticles for treating gastrointestinal disorders.

METHODS

The microparticles were prepared using a spray-drying process, optimised the characteristics by biomarker loading, and encapsulation efficiency, and assessed for bioactivities related to gastrointestinal diseases.

RESULTS

The optimised microparticles were spherical, with a mean diameter of 2.11 ± 0.34 µm, a SPAN of 4.46 ± 0.68, a zeta potential of +37.6 ± 0.2 mV, loading of 15.7% w/w curcuminoids, 5.4% w/w ar-turmerone, and encapsulation efficiency of 63.26 ± 1.62% w/w curcuminoids and 43.75 ± 1.33% w/w ar-turmerone. Encapsulation of turmeric extract improved release at 6 h by 20 times and mucoadhesion by 3.6 times. The microparticles exhibited high acid-neutralising capacity (1.64 ± 0.34 mEq/g) and inhibited nitric oxide production about twice as effectively as the turmeric extract, while maintaining antioxidant and antibacterial activities.

CONCLUSION

Encapsulation of turmeric extract in chitosan microparticles effectively enhanced therapeutic potential for gastrointestinal disorders.

Standardization and Ameliorative effect of Kalyanaka ghrita in β-amyloid induced memory impairment in wistar rats

ETHNOPHARMACOLOGICAL RELEVANCE

Kalyanaka ghrita (KG) is an Ayurvedic formulation traditionally used in the treatment of Daurbalya (debility) and Smritidaurbalya (impairment of intellectual activities). Clinical studies have reported the effect of KG in the treatment of Manasmandata or Buddhimandyata which is associated with impaired learning, social adjustment and maturation.

AIM OF THE STUDY

The present study aims to standardization of KG and validation of its use in experimental models of neurodegeneration.

MATERIALS AND METHODS

KG was Standardized for biomarkers curcumin, gallic acid, tannic acid, chebulagic acid, and berberine. In male wistar rats, neurodegeneration was induced by administration of intracerebroventricular Amyloid β (Aβ_1-42). The effect of KG (oral and intranasal treatment) was evaluated through behavioral parameters such as Morris water maze, social recognition test, novel object recognition, locomotor activity, and molecular parameters, brain acetylcholinesterase, brain-derived neurotrophic factor (BDNF), inflammatory cytokines, oxidative stress markers, and antioxidants. Brain histopathology was performed for studying the architecture of the brain and plaque formation.

RESULTS AND DISCUSSION

A novel HPLC method has been developed for the standardization of KG. Treatment with KG significantly improved cognition and memory and increased brain BDNF and antioxidant status in Aβ_1-42 induced rats. It also reduced brain acetylcholinesterase, oxidative stress, and inflammatory cytokines and prevented neuronal damage. There were more marked effects with intra-nasal administration compared to oral treatment.

CONCLUSION

The findings suggest that KG has neuroprotective potential and along with its nootropic property could be a promising therapy for neurodegenerative diseases like Alzheimer's disease.

Non-target bioactive compound profiles of coffee roasts and preparations

Coffee is an inherent part of our daily nutrition and seems to have protective effects against diseases, whereby it is often not fully understood, which ingredients are responsible for the observed effect. Hence, a non-targeted bioactivity profiling was developed to investigate 27 hand-filtered coffee brews of differently roasted coffee beans and 14 differently prepared and stored coffee brews. After separation, multi-imaging, and densitometry, six planar effect-directed assays were performed to reveal individual antioxidative, antibacterial, anti-cholinesterase, anti-diabetic, and estrogenic effects. Individual compounds were mainly responsible for the observed effects, e.g. 5-O-caffeoylquinic acid regarding antioxidative potential and α-glucosidase inhibition, while coffee brews made by a fully automated coffee machine showed the highest antioxidative potential. Unlike preparation and storage conditions, applied roasting conditions and origin of coffee samples played a less important role. Therefore, the way we daily consume our coffee has an impact on the magnitude of potential health effects.

Effect-Directed Profiling of Strawberry Varieties and Breeding Materials via Planar Chromatography and Chemometrics

Strawberries are an important fruit in the European diet because of their unique taste and high content of essential nutrients and bioactive compounds. The anthocyanins are known to be colorful phenolics in strawberries. In 17 samples of six strawberry cultivars produced in Serbia, i.e., the common varieties Alba, Asia, and Clery as well as promising breeding materials (11.29.11, 11.34.6, and 11.39.3), the anthocyanin profile as well as antimicrobial and antioxidative activity profiles were determined. All investigated extracts showed antioxidative and antibacterial activities against Gram-negative Aliivibrio fischeri. The responses were quite similar in number and intensity. The HPTLC-DPPH• scavenging assay and HPTLC-Aliivibrio fischeri bioassay coupled with high-resolution mass spectrometry identified pelargonidin-3-O-glucoside (Pg-3-glc) as the main anthocyanin and prominent antioxidative and antimicrobial compound in strawberries. The density functional theory calculations at the M06-2X/6-31+G(d,p) level showed that Pg-3-glc quenches free radicals via sequential proton loss electron transfer mechanism in water and in pentyl ethanoate, where the 5-OH group is the most reactive site for proton and hydrogen atom transfer. The results were confirmed via spectrophotometry. The highest total phenolic content was found in Clery and 11.39.3, while statistically significant differences between the genotypes regarding the antioxidant activity were not confirmed. Although very similar in the anthocyanin, antioxidative, and antimicrobial profile patterns, the strawberry genotypes were successfully classified using principal component analysis.

Quality Assessment of Apple and Grape Juices from Serbian and German Markets by Planar Chromatography-Chemometrics

The high consumption of plant-based foods on a global scale has increased the number of adulterations in the food industry. Along with this, analytical approaches to fraud detection need to be further developed. A nontargeted effect-directed profiling by high-performance thin-layer chromatography hyphenated with five effect-directed assays (free radical scavenging assay, Aliivibrio fischeri bioassay, and acetylcholinesterase, butyrylcholinesterase, and tyrosinase inhibition assays) and multi-imaging provided additional information on the antioxidative, antimicrobial, and enzyme inhibition activities for 18 apple and 18 grape juices from markets in Serbia and Germany. Bioactive zones of interest were eluted using an elution head-based interface and further characterized by electrospray ionization high-resolution mass spectrometry. The different profiles were evaluated chemometrically, and several compounds, which were characteristic of samples from different markets located in Serbia and Germany, were identified in apple juice (such as chlorogenic acid, phloridzin, epicatechin, and caffeic acid) and grape juice (such as chlorogenic acid, epicatechin, and quercetin). The developed rapid and simple method for the quality assessment of fruit juices coming from different (geographic) markets showed clear quality differences. Thus, it could be used to learn more about quality differences, to detect fraud in fruit juice production, and to verify the authenticity of the origin.

Puree and Juice of Thai Mango and Pineapple Analyzed by High-Performance Thin-Layer Chromatography Hyphenated with Effect-Directed Assays

The requirements for analytical tools are changing due to the global production chain, the increasing cases of adulteration, and the growing trend towards consumption of plant-based food products worldwide. The assessment of bioactivity of natural foods is currently not a quality criterion, and a paradigm shift is postulated. A non-targeted effect-directed profiling by high-performance thin-layer chromatography hyphenated with five different effect-directed assays was developed exemplarily for the puree and juice products of mango Mangifera indica L. (Anacardiaceae) and pineapple Ananas comosus (L.) Merr. (Bromeliaceae). Several bioactive compounds were detected in each sample. The additional bioactivity information obtained through effect-directed profiles improves, expands and modernizes product control. Non-target effect-directed profiling adds a new perspective to previous target analysis results that can be used not only to ensure health claims based on bioactive compounds, but also to detect unknown bioactive compounds coming from contamination or residues or changes caused by food processing.

Effect-directed profiling of 32 vanilla products, characterization of multi-potent compounds and quantification of vanillin and ethylvanillin

Food testing is of great importance to the food industry and organizations to verify the authenticity claims, to prove the quality of raw materials and products, and to ensure food safety. The market prices of vanilla differed by a factor of about 20 in the last three decades. Therefore the risk of adulteration and counterfeiting of vanilla products is high. Instead of commonly used target analyses and sum parameter assays, a complementary non-target multi-imaging effect-directed screening was developed, which provided a new perspective on the wide range of vanilla product qualities on the market. Planar chromatography was combined with effect-directed assays, and the obtained biological and biochemical profiles of 32 vanilla products from nine different categories revealed a variety of active ingredients. Depending on the region, typical vanilla product profiles and activity patterns were obtained for pods, tinctures, paste (inner part), oleoresin and powders. However, some vanilla products showed additional active compounds and a different intensity pattern. The vanilla product profiles substantially differed from those of vanilla aroma or products containing synthetic vanillin or vanilla-flavored food products. Bioactive compounds of interest were online eluted and further characterized via HPTLC-HRMS, which allowed their tentative assignment. After purchase of the standards, these were successfully confirmed by co-chromatography. Quantification of vanillin across nine different product categories revealed levels ranging from 1 µg/g to 36 mg/g with a mean repeatability of 1.9%. The synthetic ethylvanillin was not detected in the investigated samples in significant concentrations. The assessment of differences in the activity patterns pointed to highly active compounds, which were not detected at UV/Vis/FLD but first via the biological and enzymatic assays. This effect-directed profiling bridges the gap from analytical food chemistry to food toxicology, and thus, makes an important contribution to consumer safety. In the same way, it would accelerate investigations for Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) according to Regulation (EC) No. 1907/2006.

The effects of curcumin supplementation on endothelial function: A systematic review and meta-analysis of randomized controlled trials

Impaired endothelial function is an important risk factor for cardiovascular disease (CVD). Curcumin supplementation might be an appropriate approach to decrease the complications of CVD. Randomized controlled trials assessing the effects of curcumin supplementation on endothelial function were included. Two independent authors systematically searched online database including EMBASE, Scopus, PubMed, Cochrane Library, and Web of Science with no time restriction. Cochrane Collaboration risk of bias tool was applied to assess the methodological quality of included trials. Between-study heterogeneities were estimated using the Cochran's Q test and I-square (I² ) statistic. Data were pooled using a random-effects model, and weighted mean differences (WMDs) were considered as the overall effect sizes. Ten studies with 11 effect sizes were included. We found a significant increase in flow-mediated dilation (FMD) following curcumin supplementation (WMD: 1.49; 95% CI [0.16, 2.82]). There was no effect of curcumin supplement on pulse wave velocity (PWV; WMD: -41.59; 95% CI [-86.59, 3.42]), augmentation index (Aix; WMD: 0.71; 95% CI [-1.37, 2.79]), endothelin-1 (ET-1; WMD: -0.30; 95% CI [-0.96, 0.37]), and soluble intercellular adhesion molecule-1 (sICAM-1; WMD: -10.11; 95% CI [-33.67, 13.46]). This meta-analysis demonstrated the beneficial effects of curcumin supplementation on improving FMD, though it did not influence PWV, Aix, Et-1, and sICAM-1.

A Critical Review of the Properties and Analytical Methods for the Determination of Curcumin in Biological and Pharmaceutical Matrices

Curcumin, a natural compound extracted from turmeric (Curcuma longa), has been extensively studied because of its various pharmacological properties, such as anti-inflammatory, antioxidant, antibiotic, antiprotozoal, immunomodulatory, anti-proliferative, antitumor, and anticarcinogenic effects. However, low solubility in aqueous media has limited its therapeutic applications. To overcome these bioavailability issues, the use of drug delivery systems providing localized or targeted delivery of this drug may represent a more viable therapeutic option. Several drug delivery systems have been shown to significantly enhance the therapeutic efficacy of curcumin. Additionally, a wide variety of analytical methods are available for the qualitative and quantitative analysis of curcumin in different matrices, including plant extracts, biological fluids, and drug delivery systems. There are a variety of methodologies to quantify curcumin, but chromatographic and spectroscopic techniques are the ones most commonly used. Thus, in this review, we evaluate the biological properties of curcumin, as well as its nanotechnology-based delivery systems and methods of analysis.

Effect-directed analysis of ginger (Zingiber officinale) and its food products, and quantification of bioactive compounds via high-performance thin-layer chromatography and mass spectrometry

Decision makers responsible for quality management along the food chain need to reflect on their analytical tools that should ensure quality of food and especially superfood. The "4ables" in target analysis (stable, extractable, separable, detectable) focusing on marker compounds do not cover all relevant information about the sample. On the example of ginger, a streamlined quantitative bioprofiling was developed for effect-directed analysis of 17 commercially available ginger and ginger-containing products via high-performance thin-layer chromatography (HPTLC-UV/Vis/FLD-bioassay). The samples were investigated concerning their active profile as radical scavengers, antimicrobials, estrogen-like activators and acetylcholinesterase/tyrosinase inhibitors. The [6]-gingerol and [6]-shogaol content of the different products ranged 0.2-7.4mg/g and 0.2-3.0mg/g, respectively. Further, multipotent compounds were discovered, characterized, and for example, assigned as [8]- and [10]-gingerol via HPTLC-ESI-HRMS. The developed bioprofiling is a step forward to new analytical methods needed to inform on the true product quality influenced by cultivation, processing, and storage.

Bioprofiling of Cosmetics with Focus on Streamlined Coumarin Analysis

Facing the widespread use of cosmetic products in daily use and recognizing the very limited information obtained by target analysis, a method suited for comprehensive characterization of cosmetics was aimed at. The biological activity of ingredients of 20 cosmetics taken from 16 different product groups and their coumarin contents were investigated via chromatography linked to bioassays (direct bioautography) and mass spectrometry. It allows for screening a large number of cosmetic products within a short time to generate a more valid database on their coumarin content and their contribution to the overall exposure. Bioactivity profiling of cosmetics with regard to bioactive ingredients opens new avenues for a comprehensive characterization of important substances in products of daily use, helpful for the legally required safety and risk assessment of cosmetic products, especially for multiple product usage. As for coumarin, a ubiquitary fragrance compound of allergenic potential, which is under recurrent discussion due to its hepatoxic properties, it is necessary to be able to estimate the regular intake via cosmetics for a valid risk assessment. This newly developed bioprofiling method allowed a selective determination of coumarin down to 1.3 mg kg-1, even for very matrix-rich cosmetics despite minimalism in sample preparation. The declaration limits according to European Cosmetics Regulation were completely covered. Mean coumarin contents of 20 cosmetic products reached up to 2218 mg kg-1. The repeatabilities (%RSD, n = 3) were between 1.1 and 2.9%, and the mean recoveries (n = 5) were between 96 and 102% for the different cosmetic matrices.

Protective role of ellagitannins from Eucalyptus citriodora against ethanol-induced gastric ulcer in rats: impact on oxidative stress, inflammation and calcitonin-gene related peptide

The gastroprotective activity of an ellagitannin-rich fraction obtained from Eucalyptus citriodora (ECF) was investigated against ethanol-induced gastric ulceration in rats. The rats were pretreated with ECF (25, 50 and 100mg/kg) 1h before the administration of absolute ethanol to induce acute gastric ulceration. The gastric lesions were significantly reduced by all doses of ECF. Notably, pre-treatment with ECF (100mg/kg) conferred 99.6% gastroprotection, which is significantly higher than that produced by omeprazole. Moreover, ECF administration markedly increased the mucin content in a dose-dependent manner. The potent gastroprotective effect of ECF could be partly mediated by attenuating ethanol-induced oxidative stress. ECF-pre-treatment markedly increased the depleted GSH and SOD levels in a dose-dependent manner. Moreover, ECF significantly decreased the elevated MDA tissue levels induced by ethanol administration. The results demonstrated that ECF administration exerted a powerful anti-inflammatory activity as evidenced by the reduction in the pro-inflammatory markers; IL-1β, TNF-α, 5-LO and COX-2. Additionally, the caspase-3 tissue levels were significantly reduced in the groups pre-treated with ECF. These results suggest that ECF could exert a beneficial gastroprotective effect through their antioxidant, anti-inflammatory and anti-apoptotic properties. Furthermore, ECF pre-treatment significantly attenuated the ethanol-induced decrease in CGRP expression, which has a protective role against gastric ulceration. Histopathological examination revealed intact mucosal layer, absence of hemorrhage and necrosis in groups treated with ECF. Ellagitannins were identified as the major active constituents responsible for the marked antioxidant and gastroprotective properties of ECF. The HPLC-PDA-ESI/MS/MS technique was employed to identify the ellagitannins of E. citriodora.

Curcumin dose-dependently improves spermatogenic disorders induced by scrotal heat stress in mice

Curcumin significantly improves testicular injuries (B & C) induced by scrotal heat stress in a dose-dependent manner (20, 40, and 80 mg kg⁻¹; D–F, respectively).

Oridonin exerts protective effects against hydrogen peroxide‑induced damage by altering microRNA expression profiles in human dermal fibroblasts

The aim of the present study was to evaluate the protective effects of oridonin on hydrogen peroxide-induced cytotoxicity in normal human dermal fibroblasts (NHDFs) using microRNA (miRNA) expression profile analysis. Oridonin was not cytotoxic at low doses (≤5 µM) in the NHDFs, and pre-treatment of the cells with oridonin significantly reduced hydrogen dioxide (H2O2)-mediated cytotoxicity and cell death. Whereas oridonin showed no free radical scavenging activity in in vitro and in vivo antioxidant assays, treatment of the NHDFs with oridonin was associated with intracellular scavenging of reactive oxygen species. High-density miRNA microarray analysis revealed alterations in the expression profiles of specific miRNAs (5 upregulated and 22 downregulated) following treatment with oridonin in the H2O2-treated NHDFs. Moreover, the use of a miRNA target-gene prediction tool and Gene Ontology analysis demonstrated that these miRNAs are functionally related to the inhibition of apoptosis and cell growth. These data provide valuable insight into the cellular responses to oridonin in H2O2-induced damage in NHDFs.

Ethnopharmacological and bioactivity guided investigation of five TCM anticancer herbs

ETHNOPHARMACOLOGICAL RELEVANCE

Five herbs, Curcuma longa L. (CL), Scutellaria baicalensis Georgi (SBC), Scutellaria barbata D. Don (SBB), Hedyotis diffusa Willd. (HD) and Solanum nigrum L. (SN), are often prescribed in the polyherbal formulas for cancer treatment by traditional Chinese medicine (TCM) practitioners. The purpose of the present study was to identify important anticancer herbs used in TCM and carry out bioactivity-directed fractionation and isolation (BDFI) using six cancer cell lines as well as peripheral blood mononuclear cells (PBMCs), to identify constituents with anticancer activity but devoid of toxic effects against healthy immune cells.

MATERIALS AND METHODS

Of 243 document anticancer TCM treatments, 199 anticancer TCM herbs were ranked by the number of literature reports for each herb. Five herbs were identified from the top 50 ranked herbs by at least two out of three TCM practitioners as frequently used in the TCM treatment of cancer. BDFI using MTS assay was applied to determine the active anticancer extracts, fractions, and finally discrete compounds.

RESULTS

Five herbs were selected for study of their anticancer activities. The extracts of Curcuma longa L., Scutellaria barbata D. Don, and Hedyotis diffusa showed antiproliferative activity to various extents, extracts of Scutellaria baicalensis Georgi and Solanum nigrum L. showed little anticancer activity. Seven out of the 21 fractions obtained from Hedyotis diffusa Willd. showed anticancer activity. One new compound, ethyl 13(2) (S)-hydroxy-chlorophyllide a(1), along with 10 known compounds, i.e. 2-methyl-3-methoxyanthraquinone (2), 2-hydroxymethylanthraquinone(3), 2-hydroxy-3-methylanthraquinone(4), 2-hydroxymethy-1-hydroxyanthraquinone(5), 1-methoxy-2-hydroxyanthraquinone(6), 2-hydroxy-3-methyl-1-methoxyanthraquinone (7), oleanolic acid (8), ursolic acid (9), stigmasterol (10) and docosanoic acid (11), were isolated and identified. Compounds 2-6, 8 and 9 dose-dependently inhibited the cell viability of cancer cells within a concentration range of 1-200µM. Furthermore, compounds 2, 3, 5 and 9 showed significantly stronger inhibition of tested cancer cell lines than on that of PBMCs.

CONCLUSION

This study identified anticancer herbs, extracts, fractions and eventually compounds from the documented anticancer TCM herbs by using BDFI. It also determined the antiproliferative activity in cancer and healthy immune cells of the isolated compounds from Hedyotis diffusa. The results will be useful in the validation of the clinical application of these herbs and the development of novel anticancer therapeutics.

Antioxidant markers based TLC-DPPH differentiation on four commercialized botanical sources of Shankhpushpi (A Medhya Rasayana): A preliminary assessment

Shankhpushpi is a cognition boosting traditional ayurvedic brain supplement. Convolvulus pluricaulis (Convolvulaceae), Evolvulus alsinoides (Convolvulaceae), Clitoria ternatea (Papilionaceae), and Canscora decussata (Gentianaceae) are botanical claimants of Shankhpushpi. This investigation is to focus the identification of the compound based on biological marker differentiation of four botanical claimants of Shankhpushpi for their antioxidant evaluation on thin layer chromatography (TLC) by 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. A rapid TLC-DPPH method was developed to identify and differentiate four botanical claimants of Shankhpushpi in terms of presence of β-carotene, rutin, scopoletin, chlorogenic acid, and mangiferin. C. pluricaulis shows presence of scopoletin; E. alsinoides shows presence of β-carotene, scopoletin, and chlorogenic acid; C. ternatea shows presence of β-carotene, scopoletin, and rutin; and C. decussata shows presence of β-carotene, scopoletin, and mangiferin. The order, they followed, based on their antioxidant potential is β-carotene < mangiferin < rutin < scopoletin < chlorogenic acid. Antioxidants are attributed for their beneficial role in age-related cognition decline. The proposed method provides an edge in terms of identification and quantification of antioxidant constituents in a multi-component system. This method may also provide application for identification of correct plant sources used in the name of Shankhpushpi in marketed ayurvedic formulation, food supplement, and extracts.

Free radical scavenging activities of polyphenolic compounds isolated from Medicago sativa and Medicago truncatula assessed by means of thin-layer chromatography DPPH˙ rapid test

INTRODUCTION

The structure of polyphenolic compounds influences their anti-oxidant potential. Finding a simple, rapid and reliable analytical method to study the structure-activity relationships for numerous samples is challenging.

OBJECTIVE

To develop a simple thin-layer chromatography-2,2-diphenyl-1-picrylhdrazyl (TLC-DPPH˙) protocol with image processing to study the influence of the structure of polyphenols on observed direct anti-oxidant properties.

METHODOLOGY

First, compounds exhibiting free radical scavenging activities were chosen from among the isolated compounds with the application of a rapid TLC dot-blot test. The active ones were further chromatographed on silica gel plates using the mobile phase: acetonitrile:water:chloroform:formic acid (60:15:10:5, v/v/v/v). Subsequently the plates were stained with DPPH˙ methanolic solution. An improved image processing protocol was used to quantitatively measure the polyphenols' activity.

RESULTS

The application of a properly optimised chromatographic system enabled separation of the investigated compounds from dimethyl sulphoxide (DMSO) that influences the results of an anti-oxidant test. New solutions enabling better data processing are proposed. It has been discovered that acylation of flavonoid glycosides with hydroxycinnamic acids increases their direct anti-oxidant properties. Some of the analysed glycosides acylated with ferulic acid molecule were found to be the most potent free radical scavengers from among those analysed. The amount of sugar moieties as well as their type also influenced the observed activity.

CONCLUSION

A simple, rapid and reliable TLC-DPPH˙ test with image processing has been developed enabling comparison of free radical scavenging activity of plant polyphenols. The influence of different structural features on the observed activity was measured successfully.

High-sensitivity determination of curcumin in human urine using gemini zwitterionic surfactant as a probe by resonance light scattering technique

INTRODUCTION

Curcumin is a popular plant medicine that is extracted from turmeric dry rhizomes of Curcuma longa Linn. The study of curcumin is well established and is currently becoming a centre of attention.

OBJECTIVE

To develop a steady and simple assay for curcumin determination at the nanogram level based on the intense resonance light scattering (RLS) enhancement due to the interaction between curcumin and phosphodiesters quaternary ammonium salt (PQAS).

METHODOLOGY

PQAS, a new kind of Gemini zwitterionic surfactant, was used as the probe for the determination of curcumin by the RLS technique. A series of validation experiments was also performed.

RESULTS

A linear relationship was constructed between the ΔI(RLS) and the concentration of curcumin. The linear regression equation was presented as ΔI(RLS)  = 8.37 + 44.92c (µg/mL) with the regression coefficient r = 0.9987 (n = 12) and the linear range was 0.08-60.0 µg/mL. The detection limit (3σ) was 2.6 ng/mL.

CONCLUSION

The proposed method can be used to detect the content of curcumin in human urine samples and this new assay using PQAS as a probe was more sensitive and displayed a wider linear range than that reported previously.

Approach to develop a standardized TLC-DPPH• test for assessing free radical scavenging properties of selected phenolic compounds

TLC-DPPH(•) test belongs to a group of frequently performed assays aimed at detection of compounds with desired activity (effect directed analysis). Despite its popularity a standard procedure has not been elaborated so far causing difficulties in comparing results obtained in different laboratories. Thus the aim of the presented research was an approach to develop a standardized procedure for assessing free radical scavenging properties of plant polyphenols. It was observed that specifically positive adsorbent (silica gel) strengthened the observed result of radical-antioxidant reaction, while polar bonded stationary phase CN-silica weakened it. Based on the observed results it was concluded that the TLC-DPPH(•) assay should be preferably performed on the surface of non-specific adsorbents (e.g.: RP-18) with the use of n-hexane for DPPH(•) dissolution. It is also proposed to document the results every 5 min after staining, as they change in time.

Antioxidant activity and protecting health effects of common medicinal plants

Medicinal plants are traditionally used in folk medicine as natural healing remedies with therapeutic effects such as prevention of cardiovascular diseases, inflammation disorders, or reducing the risk of cancer. In addition, pharmacological industry utilizes medicinal plants due to the presence of active chemical substances as agents for drug synthesis. They are valuable also for food and cosmetic industry as additives, due to their preservative effects because of the presence of antioxidants and antimicrobial constituents. To commonly used medicinal plants with antioxidant activity known worldwide belong plants from several families, especially Lamiaceae (rosemary, sage, oregano, marjoram, basil, thyme, mints, balm), Apiaceae (cumin, fennel, caraway), and Zingiberaceae (turmeric, ginger). The antioxidant properties of medicinal plants depend on the plant, its variety, environmental conditions, climatic and seasonal variations, geographical regions of growth, degree of ripeness, growing practices, and many other factors such as postharvest treatment and processing. In addition, composition and concentration of present antioxidants, such as phenolic compounds, are related to antioxidant effect. For appropriate determination of antioxidant capacity, the extraction technique, its conditions, solvent used, and particular assay methodology are important.

Development of chromatographic and free radical scavenging activity fingerprints by thin-layer chromatography for selected Salvia species

INTRODUCTION

Plant-derived free radical scavengers have become the subject of intensive scientific interest. Recently, the concept of coupling chromatographic fingerprints with biological fingerprinting analysis has gained much attention for the quality control of plant extracts. However, identification of free radical scavenging activity of each single compound in a complex mixture is a difficult task. Thin-layer chromatography with post-chromatographic derivatisation with the methanol solution of DPPH can be a valuable tool in such analyses.

OBJECTIVE

Development of chromatographic and free radical scavenging fingerprints of nineteen Salvia species grown and cultivated in Poland.

METHODOLOGY

Chromatography was performed on the silica gel layers with use of two eluents, one for the resolution of the less polar compounds, and the other one for the resolution of the medium and highly polar ones. The plates were sprayed with the vanillin-sulfuric acid reagent to produce chemical fingerprints, and with DPPH solution to generate free radical scavenging fingerprints.

RESULTS

With four Salvia species, it was revealed that their strong free radical scavenging properties are not only due to the presence of polar flavonoids and phenolic acids, but also due to the presence of several free radical scavengers in the less polar fraction. Because of the similarities in both the chromatographic and the free radical scavenging fingerprints, S. triloba can be introduced as a possible equivalent of the pharmacopoeial species, S. officinalis.

CONCLUSION

Fingerprints developed in the experiments proved useful for the analysis of complex extracts of the different Salvia species.

A simple isocratic HPLC method for the simultaneous determination of curcuminoids in commercial turmeric extracts

INTRODUCTION

Turmeric (Curcuma longa) extracts contain three curcuminoids (curcumin, desmethoxycurcumin and bisdesmethoxycurcumin) as major bioactive substances. Previously reported HPLC-UV methods for the determination of curcuminoids have several disadvantages, including unsatisfactory separation times, poor resolution and/or complicated solvent mixtures with gradient elution.

OBJECTIVE

To develop a simple isocratic HPLC-UV method for the simultaneous determination of individual curcuminoids for the quality control of turmeric extracts.

METHODOLOGY

The sample was prepared by dissolving the extract in acetonitrile and subsequently diluting with 50% acetonitrile. This solution was analysed by reverse-phase chromatography on an Alltima C(18) column with isocratic elution of acetonitrile and 2% v/v acetic acid (40:60, v/v) at a flow rate of 2.0 mL/min, a column temperature of 33 degrees C, and UV detection at 425 nm. The method was validated and applied for quantification of individual curcuminoids in commercial turmeric extracts.

RESULTS

The method allowed simultaneous determination of curcumin, desmethoxycurcumin and bisdesmethoxycurcumin in the concentration ranges of 10-60, 4-24 and 0.5-3.0 microg/mL, respectively. The limits of detection and quantification were, respectively, 0.90 and 2.73 microg/mL for curcumin, 0.84 and 2.53 microg/mL for desmethoxycurcumin and 0.08 and 0.23 microg/mL for bisdesmethoxycurcumin, and the percentage recoveries were, respectively, 99.16-101.75 (%RSD < or = 1.11%), 99.50-101.01 (%RSD < or = 1.74%) and 99.67-101.92 (RSD < or = 1.31%).

CONCLUSION

The method was found to be simple, accurate and precise and is recommended for routine quality control analysis of turmeric extracts containing the three curcuminoid compounds as the main principles in the herb.

Purification of curcumin, demethoxycurcumin, and bisdemethoxycurcumin by high-speed countercurrent chromatography

Curcuminoids are substances of great interest because of their important pharmacological activities, particularly anti-inflammatory, anticarcinogenic, and anti-Alzheimer's activities. In this study, we report the first procedure and effect of processing for the high, efficient, and useful purification of curcumin, demethoxycurcumin, and bisdemethoxycurcumin from turmeric powder. Purification involves high-speed countercurrent chromatographic (HSCCC) separation of these curcuminoids using a simple two-phase solvent system composed of n-hexane/chloroform/methanol/water (5/10/7.5/2.5, v/v). The HSCCC-fractionated effluent peaks indicated that the peak resolutions were 1.7 between curcumin and demethoxycurcumin and 2.1 between demethoxycurcumin and bisdemethoxycurcumin for 25 mg of loaded turmeric powder. These purified substances were analyzed by liquid chromatography-tandem mass spectrometry with scan and daughter scan negative modes, and the wide absorbance from 200 to 500 nm was monitored by photodiode array detection. The separation yielded 1.1 mg of curcumin, 0.6 mg of demethoxycurcumin, and 0.9 mg of bisdemethoxycurcumin (>98% purity). Moreover, the antioxidant effect of curcuminoids was measured by a 1,1-diphenyl-2-picrylhydrazil assay. The order of antioxidant activity was purified curcumin > purified demethoxycurcumin > purified bisdemethoxycurcumin > turmeric powder. Curcumin, demethoxycurcumin, and bisdemethoxycurcumin can be used for various evaluations of their pharmacological activities.

Capillary zone electrophoresis for separation and analysis of four diarylheptanoids and an alpha-tetralone derivative in the green walnut husks (Juglans regia L.)

A fast capillary zone electrophoresis (CZE) method for the simultaneous determination of four cyclic diarylheptanoids (rhoiptelol, RH; juglanin A, JA; juglanin B, JB; juglanin C, JC) and an alpha-tetralone derivative (sclerone, SC) in the extract of the green walnut husks (Juglans regia L.) was developed. The optimized buffer was composed of 25 mM sodium tetraborate at pH 10.3. The applied voltage was 20 kV and the capillary temperature was kept constant at 20 degrees C. The detection wavelength was set at 220 nm using a photodiode array detection. The effects of several CE parameters, including pH value, buffer concentration, applied voltage and separation temperature on the separation were investigated systematically. Regression equations showed good linear relationships (correlation coefficients: 0.9996-0.9999) between the peak area of each compound (RH, JA, JB, JC and SC) and its concentration accordingly. The relative standard deviations (R.S.D.) of the migration time and peak area were less than 0.57 and 3.44% (intra-day), and 0.97 and 3.71% (inter-day), respectively. The contents of the five active compounds in the green walnut husks (J. regia L.) from different origins were determined with satisfactory repeatability and recovery.