Direct characterisation of phenolic antioxidants in infusions from four Mapuche medicinal plants by liquid chromatography with diode array detection (HPLC-DAD) and electrospray ionisation tandem mass spectrometry (HPLC-ESI–MS)

Oxidative stress promotes cytotoxicity in human cancer cell lines exposed to Escallonia spp. extracts

BACKGROUND

Standard cancer treatments show a lack of selectivity that has led to the search for new strategies against cancer. The selective elimination of cancer cells modulating the redox environment, known as "selective oxycution", has emerged as a viable alternative. This research focuses on characterizing the unexplored Escallonia genus plant extracts and evaluating their potential effects on cancer's redox balance, cytotoxicity, and activation of death pathways.

METHODS

36 plant extracts were obtained from 4 different species of the Escallonia genus (E. illinita C. Presl, E. rubra (Ruiz & Pav.) Pers., E. revoluta (Ruiz & Pav.) Pers., and E. pulverulenta (Ruiz & Pav.) Pers.), which were posteriorly analyzed by their phytoconstituents, antioxidant capacity, and GC-MS. Further, redox balance assays (antioxidant enzymes, oxidative damage, and transcription factors) and cytotoxic effects (SRB, ∆Ψmt, and caspases actives) of those plant extracts were analyzed on four cell lines (HEK-293T, MCF-7, HT-29, and PC-3).

RESULTS

36 plant extracts were obtained, and their phytoconstituents and antioxidant capacity were established. Further, only six extracts had EC50 values < 10 µg*mL- 1, indicating high toxicity against the tested cells. From those, two plant extracts were selective against different cancer cell lines: the hexane extract of E. pulverulenta´s stem was selective for HT-29, and the ethyl acetate extract of E. rubra´s stem was selective for PC-3. Both extracts showed unbalanced redox effects and promoted selective cell death.

CONCLUSIONS

This is the first study proving "selective oxycution" induced by Chilean native plant extracts.

New bioactive compounds characterized by liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry in hydro-methanol and petroleum ether extracts of Prosopis farcta (Banks & Sol.) J. F. Macbr weed

The purpose of this study was to identify and characterize the chemical composition present in aerial parts of Prosopis farcta in petroleum ether and hydro-methanol extracts through LC-PDA-ESI-MS/MS and GC-MS techniques respectively for the first time. The plant samples were collected from northeast of Iran during maturity stage. LC-MS/MS profile revealed 47 phenolic compounds in hydro-methanol extracts, including phenolic acids, flavonoids, and their glycoside derivatives. Flavonoid-O-glycosides (19), flavonoid aglycones (11), phenolic acid derivatives (9), flavonoid-C-glycosides (4), and flavonoid-O, C-glycosides (1) were dominant class phenolics in all studied parts. The extracts contained a significant amount of major compounds, including gallic and vanillic acids, luteolin, apigenin, phloridzin, and vicenin-2. Also, GC-MS analysis of petroleum ether extracts showed that fatty acids, organic acids, steroids, terpenoids, and hydrocarbons were the group of major compounds in all parts. Twenty-four, 27, and 25 components were identified, which represent 99.2%, 96.1%, and 99.4% of the total composition in fruits, leaves, and stems, respectively. These results suggested that other genetic resources of P. farcta can be further explored to screen genotypes with high bioactive compounds and purification of phytochemical compounds, which are valuable to produce, expand, and develop natural antioxidants in production of bio-medicine and food.

Catharanthus roseus (L.) G. Don: A review of its ethnobotany, phytochemistry, ethnopharmacology and toxicities

ETHNOPHARMACOLOGICAL RELEVANCE

Catharanthus roseus (L.) G. Don is a well known medicinal plant belonging to family Apocynaceae that have been traditionally used as medicine since ancient times. C. roseus is a well-recognized herbal medicine due to its anticancer bisindole alkaloids (vinblastine (111), vincristine (112) and vindesine (121)). In the Ayurvedic system of medicine, different parts of C. roseus are used in folklore herbal medicine for treatment of many types of cancer, diabetes, stomach disorders, kidney, liver and cardiovascular diseases.

AIM OF THE STUDY

The main idea behind this communication is to update comprehensively and analyze critically the traditional applications, phytochemistry, pharmacological activities, and toxicity of various extracts and isolated compounds from C. roseus.

MATERIALS AND METHODS

The presented data covers scientific works on C. roseus published across the world between 1967 and 2021 was searched from various international publishing houses using search engines as well as several traditional texts like Ayurveda and relevant books. Collected data from different sources was comprehensively summarized/analyzed for ethnomedicinal uses, phytochemistry, analytical chemistry, biological activities and toxicity studies of C. roseus.

RESULTS AND DISCUSSION

C. roseus has a wide range of applications in the traditional system of medicine especially in cancer and diabetes. During phytochemical investigation, total of 344 compounds including monoterpene indole alkaloids (MIAs) (110), bisindole alkaloids (35), flavonoids (34), phenolic acids (9) and volatile constituents (156) have been reported in the various extracts and fractions of different plant parts of C. roseus. The extracts and isolated compounds of C. roseus have to exhibit many pharmacological activities such as anticancer/cytotoxic, antidiabetic, antimicrobial, antioxidant, larvicidal and pupicidal. The comparative toxicity of extracts and bioactive compounds investigated in dose dependent manner. The investigation of toxicity showed that the both extracts and isolated compounds are safe to a certain limit beyond that they cause adverse effects.

CONCLUSION

This review is a comprehensive, critically analyzed summarization of sufficient baseline information of selected topics in one place undertaken till date on C. roseus for future works and drug discovery. The phytochemical investigation including biosynthetic pathways showed that the MIAs and bisindole alkaloids are major and characteristic class of compounds in this plant. The present data confirm that the extracts/fractions and their isolated alkaloids especially vinblastine (111) and vincristine (112) have a potent anticancer/cytotoxic and antidiabetic property and there is a need for further study with particular attention to the mechanisms of anticancer activity. In biosynthesis pathways of alkaloids especially bisindole alkaloids, some enzymes and rearrangement are unexposed therefore it is required to draw special attention. It also focuses on attracting the attention of scientific communities about the widespread biological activities of this species for its better utilization prospects in the near future.

Ethnopharmacology, Phytochemistry and Biological Activities of Native Chilean Plants

The native flora of Chile has unique characteristics due to the geographical situation of the country, with the vast desert in the North, Patagonia in the South, the Andean Mountains on the east and the Pacific Ocean on the west. This exclusivity is reflected in high concentrations of phytochemicals in the fruits and leaves of its native plants. Some examples are Aristotelia chilensis (Molina), Stuntz (maqui), Berberis microphylla G. Forst. (calafate), Peumus boldus Molina (boldo), Ribes magellanicum Poir. (Magellan currant), Ugni molinae Turcz. (murtilla), Rubus geoides Sm. (miñe miñe), Drimys winteri J.R.Forst. & G.Forst. (canelo), Luma apiculata (DC.) Burret (arrayán) distributed throughout the entire Chilean territory. Some of these Chilean plants have been used for centuries in the country's traditional medicine. The most recent studies of phytochemical characterization of parts of Chilean plants show a wide spectrum of antioxidant compounds, phenolic components, terpenoids and alkaloids, which have shown biological activity in both in vitro and in vivo studies. This manuscript covers the entire Chilean territory characterizing the phytochemical profile and reporting some of its biological properties, focusing mainly on antioxidant, anti-inflammatory, antimicrobial, chemopreventive and cytotoxic activity, and potential against diabetes, metabolic syndrome and gastrointestinal disorders.

Hydroethanolic Extracts of Haplopappus baylahuen Remy and Aloysia citriodora Palau Have Bactericide Activity and Inhibit the Ability of Salmonella Enteritidis to Form Biofilm and Adhere to Human Intestinal Cells

We analysed whether the hydroethanolic extracts from leaves of Haplopappus baylahuen Remy (bailahuen) and Aloysia citriodora Palau (cedron) inhibit the growth and ability of Salmonella Enteritidis to form biofilms and to adhere to human intestinal epithelial cells. Herein, we first determined the total phenolic content and antioxidant and antibacterial activities of the extracts. Then, Salmonella Enteritidis was treated with the extracts to analyse biofilm formation by scanning electronic microscopy and the violet crystal test. We also measured the efflux pump activity of Salmonella Enteritidis since biofilm formation is associated with this phenomenon. Furthermore, the human intestinal cell line Caco-2 was infected with Salmonella Enteritidis pretreated with the extracts, and 30 min later, the number of bacteria that adhered to the cell surface was quantified. Finally, we determined by qPCR the expression of genes associated with biofilm formation, namely, the diguanilate cyclase AdrA protein gene (adrA) and the BapA protein gene (bapA), and genes associated with adhesion, namely, the transcriptional regulator HilA (hilA). The phenolic content and antioxidant and bactericide activities were higher in bailahuen than in the cedron extract. Biofilm formation was inhibited by the extracts in a dose-dependent manner, while the activity of efflux pumps was decreased only with the cedron extract. Adhesion to Caco-2 cells was also inhibited without differences between doses and extracts. The extracts decreased the expression of adrA; with the cedron extract being the most efficient. The expression of hilA is affected only with the cedron extract. We concluded that hydroethanolic extracts of bailahuen and cedron differentially inhibit the growth of Salmonella Enteritidis and affect its the ability to form biofilms and to adhere to human intestinal epithelial cells. These results highlight the presence of molecules in bailahuen and cedron with a high potential for the control of the Salmonella Enteritidis pathogenesis.

UPLC-Orbitrap HRMS metabolic profiling of Cymbopogon citratus cultivated in Egypt; neuroprotective effect against AlCl3-induced neurotoxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Cymbopogon citratus (lemongrass) is commonly used in teas, soups and treat inflammatory-based ailments, vascular and nervous disorders.

AIM OF THE STUDY

The study aimed to evaluate the neuroprotective effect of Cymbopogon citratus leaves through scientific protocol. The effect of aqueous (AE) and ethanolic (EE) extracts was evaluated against AlCl₃-induced Alzheimer's disease (AD) in rats. Metabolic profiling of the plant, isolation of bioactive compounds and standardization of the active fraction were investigated.

MATERIALS AND METHODS

AE of Cymbopogon citratus leaves was prepared as per traditional method (infusion), EE was prepared by repeated maceration in 90% ethanol, bioactive fraction (BAEE) was obtained from EE and the active compounds thereof were obtained by column chromatography. Metabolic profiling of Cymbopogon citratus was performed by UPLC-Orbitrap HRMS and HPLC was used for standardization. AlCl₃-induced Alzheimer's rats were used to assess neuroprotective effect of the extracts. Neuroprotective mechanism(s) of Cymbopogon citratus extracts was clarified through histopathological examination of brain tissues, estimation of AD biochemical markers, oxidative stress and neuroinflammation in brain homogenates. In addition, antioxidant (using DPPH assay) and anticholinesterase (using modified Ellman's method) activities were investigated.

RESULTS

AlCl₃-treated rats (17 mg/kg/day) showed histopathological alteration in brain tissues together with elevated levels of Aβ, tau proteins, MDA, NF-kB and IL-6. However, treatment with AE and EE of Cymbopogon citratus leaves prevented the pathological changes and maintained the levels of oxidative stress and inflammatory markers. In addition, BAEE significantly inhibited acetylcholinesterase enzyme (2.11 ± 0.11 mg/ml) and exhibited a strong antioxidant activity (24.99 ± 0.00 μg/ml). UPLC-MS of Cymbopogon citratus leaves showed peaks for twenty-eight compounds, twenty-one of them were identified. Three flavonoids; isoorientin, isoschaftoside and luteolin-7-O-neohesperidoside were isolated from BAEE as major constituents. The powdered leaves of Cymbopogon citratus was found to contain remarkable amounts of caffeic acid (3.49 mg/g dry wt.) and isoorientin (7.37 mg/g dry wt.) as determined by HPLC.

CONCLUSION

Cymbopogon citratus ethanolic extract attenuates AlCl₃-induced neurotoxicity in rats through inhibition of oxidative stress and inflammatory markers. This effect could possibly attributed, in part to its high content of phenolic acids and flavonoids. Accordingly, we recommend Cymbopogon citratus leaves for protection against AD.

HPLC-ESI- MS/MS analysis of beet (Beta vulgaris) leaves and its beneficial properties in type 1 diabetic rats

The phenolic profile of the leaves of Beta vulgaris subspecies vulgaris variety rubra was investigated by high-performance liquid chromatography (HPLC) coupled to electrospray ionization high resolution mass spectrometric (ESI-HRMS-MS) detection. Mass spectrometry-based molecular networking was employed to dereplicate the known compounds. Twelve known compounds, seven of which are previously undescribed as constituents in the B. vulgaris leaves were dereplicated and assigned with various levels of identification confidence. The ameliorative effects of the aqueous methanolic extract of the leaves were assessed against alloxan induced diabetic rats. It was found that the extract significantly decreased (p < 0.001) serum glucose, lipid profile, ALT, AST, TNF-α, IL-1β, IL-6, and hepatic MDA levels; and significantly increased (p < 0.001) hepatic TAO and GSH; and down-regulated the expression of hepatic NF-κB versus the untreated diabetic groups, in a dose-dependent manner. In molecular docking, all identified compounds exhibited good glide score against the PPAR-ɣ target, confirming the in vivo observed activities. In conclusion, B. vulgaris has immunomodulatory / antioxidant effects that could be helpful in slowing the progression of diabetic complications.

Metabolite Profiling of Two Maple-Derived Products Using Dereplication Based on High-Performance Liquid Chromatography-Diode Array Detector-Electrospray Ionization-Time-of-Flight-Mass Spectrometry: Sugar Maple Bark and Bud Hot-Water Extracts

Recent studies about hot-water extracts from sugar maple (Acer saccharum Marsh.) bark and buds demonstrated that they contain high amounts of phenolic structures that may be used as antioxidant food additives. However, the detailed chemical composition of these maple-derived extracts has yet to be determined. By performing high-performance liquid chromatography-diode array detector-high-resolution mass spectrometry (HPLC-DAD-HRMS)-based dereplication, we were able to spike and classify almost 100 metabolites in each hot-water extract. The sugar maple bark hot-water extract is rich in simple phenolic compounds and phenylpropanoid derivatives, while bud extract contains predominantly flavonoids, benzoic acids, and their complex derivatives (condensed and hydrolyzable tannins). Among those chemical structures, we tentatively identified 69 phenolic compounds potentially reported for the first time in the genus Acer. Considering the growing commercial demand in natural products, the phenolic fingerprints of sugar maple bark and bud hot-water extracts will help in promoting these two maple-derived products as new sources of bioactive compounds in the food, nutraceutical, and cosmetic industries.

Activity of Adesmia boronioides resinous exudate against phytopathogenic bacteria

Resinous exudate obtained from the aerial parts of Adesmia boronioides Hook.f. were evaluated to determine anti-phytopathogenic effects. Briefly, resinous exudate was obtained by dipping fresh plant material in dichloromethane; chemical composition was determined by GC-MS; and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated against four phytopathogenic bacteria. Resinous exudate yield was 8.5% (resin/fresh plant), of which esquel-6-en-9-one (14.25%), esquel-7-en-9-one (5.86%), and veratric acid (2.59%) were the effective antibacterial compounds. Tested against Pectobacterium carotovorum subsp. carotovora, Erwinia amylovora, Bacillus subtilis, and Pseudomonas syringae, MICs and MBCs ranged from 16 to 128 µg/mL and 32-256 µg/mL, respectively. These results provide initial evidence that resinous bush A. boronioides is a new and alternative source of substances with agricultural interest.

Remela de cachorro (Clavija lancifolia Desf.) fruits from South Amazon: Phenolic composition, biological potential, and aroma analysis

Remela de cachorro (Clavija lancifolia Desf.) is an Amazonian native fruit consumed specially in the Purus microregion. Because of its rarity, restricted consumption, and the lack of knowledge about its chemical composition, remela de cachorro fruit was studied in relation to its phenolic and aroma constitution. Using liquid chromatography tandem mass spectrometry (LC-MS/MS), 11 compounds (flavonoids and its glucosides along with organic acids) were tentatively identified by fragmentation patterns. A previously validated method was applied to quantify common antioxidant compounds in the raw pulps, for which kaempferol was the main compound. Gas chromatography mass spectrometry (GC-MS) with headspace solid-phase microextraction (HS-SPME) was employed to assess the aroma composition of remela de cachorro fruit. A total of 27 volatile organic compounds (VOCs) were identified for this fruit, for which benzaldehyde and linalool were the main VOCs. Furthermore, biological activities, such as antioxidant capacity (ABTS, DPPH, and ORAC methods), cytotoxicity, and α-glucosidase and lipase inhibitions of the hydroalcoholic extract of remela de cachorro fruit were evaluated. In vitro biological assays revealed the potential of this fruit as a bioactive food that should be further studied and explored in Amazonian products.

Phenolic profiles and antioxidant activity of Turkish Tombul hazelnut samples (natural, roasted, and roasted hazelnut skin)

The phenolic profiles and antioxidant status of hazelnut samples [natural (raw) hazelnut, roasted hazelnut, and roasted hazelnut skin] were compared. Free and bound (ester-linked and glycoside-linked) phenolic acids were examined using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Comprehensive identification of phenolics was carried out using Q-exactive hybrid quadrupole-orbitrap mass spectrometer (Q-OT-MS). Samples were also assessed for their total phenolics and antioxidant activities using three different assays. Ten free and bound phenolic acids were quantified in hazelnut samples. Roasted hazelnut skin contained the highest content of total phenolic acids, followed by natural and roasted hazelnuts. The majority of phenolic acids were present in the bound form. Using a Q-OT-MS, 22 compounds were tentatively identified, 16 of which were identified for the first time in hazelnut samples. The newly identified compounds consisted of flavonoids, phenolic acids and related compounds, hydrolysable tannins and related compounds, and other phenolics. Three antioxidant assays demonstrated similar trends that roasted hazelnut skin rendered the highest activity. The present work suggests that roasted hazelnut skin is a rich source of phenolics and can be considered as a value-added co-product for use as functional food ingredient and antioxidant.

Characterization and cardioprotective activity of anthocyanins from Nitraria tangutorum Bobr. by-products

Anthocyanins from the industrial by-products ofN. tangutorumjuice were composed of 16 anthocyanins derived from six anthocyanidins, and exerted an excellent protective effect on DOX-injury of H9c2 myoblast cells through multi-pathway.

Study on anti-inflammatory efficacy and correlative ingredients with pharmacodynamics detected in acute inflammation rat model serum from Caulis Lonicerae japonicae

BACKGROUND

Caulis Lonicerae japonicae (CLJ) is often used for the treatment of inflammation such as acute fever, headache, respiratory infection and epidemic diseases. Nevertheless, domestic and foreign researches simply fail to focus on reports of CLJ, especially its anti-inflammatory effects and correlative components.

PURPOSE

In this study, we investigated anti-inflammatory effects and serum components of Caulis Lonicerae japonicae (CLJ) in models of acute inflammation and correlative analysis between anti-inflammatory effects and serum components of CLJ in rat serum to analyze the changes in the relative contents of components in serum with time and in the corresponding values to characterize active fractions of CLJ and identify the major active components of CLJ in rats.

STUDY DESIGN

Active fractions of CLJ were screened using xylene-induced ear oedema mice model. Anti-inflammatory effects were evaluated using carrageenan-induced paw oedema rat model, and then correlative components in rat serum were demonstrated with HPLC-QTOF/MS/MS method explored.

METHODS

HPLC-QTOF/MS/MS was developed to analyze the components absorbed in rat serum after oral administration of CLJ.

RESULTS

Ethyl acetate extracts (ECLJ) and n-butanol extracts (BCLJ) of CLJ were preliminarily screened as active fractions of CLJ (EBCLJ) using xylene-induced ear oedema mice model, and effectively inhibited edema and values of interleukin-1 (IL-l), nuclear factor-kappaB (NF-kB), tumor necrosis factor-α (TNF-α) activities and prostaglandinE2 (PGE2) productions using carrageenan-induced paw oedema rat model. 33 peaks were found in total ion current chromatograms of EBCLJ, and 27 components were observed in EBCLJ-treated rat serum, only 11 of which were correlated with anti-inflammatory effects.

CONCLUSIONS

The present study contributes to the study on the pharmacodynamic basis of CLJ and provides potent evidence for developing CLJ as a safe and promising natural drug in inflammation treatment.

Chemical profiling and antioxidant activity of Bolivian propolis

BACKGROUND

Propolis is a relevant research subject worldwide. However, there is no information so far on Bolivian propolis. Ten propolis samples were collected from regions with high biodiversity in the main honey production places in Bolivia and were analyzed for their total phenolics (TP), flavonoids (TF) and antioxidant activity. The chemical profiles of the samples were assessed by TLC, HPLC-DAD, HPLC-DAD-MS/MS(n) and NMR analysis.

RESULTS

TP, TF, TLC and NMR analysis showed significant chemical differences between the samples. Isolation of the main constituents by chromatography and identification by HPLC-DAD-MS/MS(n) achieved more than 35 constituents. According to their profiles, the Bolivian propolis can be classified into phenolic-rich and triterpene-rich samples. Propolis from the valleys (Cochabamba, Chuquisaca and Tarija) contained mainly prenylated phenylpropanoids, while samples from La Paz and Santa Cruz contained cycloartane and pentacyclic triterpenes. Phenolic-rich samples presented moderate to strong antioxidant activity while the triterpene-rich propolis were weakly active.

CONCLUSION

High chemical diversity and differential antioxidant effects were found in Bolivian propolis. Our results provide additional evidence on the chemical composition and bioactivity of South American propolis.

Phytochemical Compounds and Antioxidant Capacity of Tucum-Do-Cerrado (Bactris setosa Mart), Brazil's Native Fruit

This study identified major phenolic compounds of the tucum-do-cerrado (Bactris setosa) peel, as well as antioxidant activity and total phytochemical compound concentration of different extracts of the peel and pulp of this fruit. Phenolic compounds of the different extracts of tucum-do-cerrado peel were identified and quantified using a high-performance liquid chromatography system coupled to a diode array detector (DAD). Total phytochemical compound content was determined by spectrophotometric assays and the antioxidant activity by ferric reducing antioxidant power and β-carotene/linoleic assays. Total phenolic, flavanols, total anthocyanins and yellow flavonoids concentration of tucum-do-cerrado were 122-, 14-, 264- and 61-fold higher in the peel than in the pulp, respectively. The aqueous, methanolic and ethanolic extracts of the tucum-do-cerrado peel exhibited higher antioxidant activity compared to its pulp. Flavanols, anthocyanins, flavones, phenolic acids and stilbenes were the main phenolic classes identified in the tucum-do-cerrado peel extracts. Results suggest that the antioxidant capacity and the phytochemical compound content of the tucum-do-cerrado are mainly associated with the peel. Although flavonoids are the main compounds identified in tucum-do-cerrado peel, other phenolics identified in minor amounts, such as phenolic acids and stilbenes, may be responsible for the high antioxidant capacity of the fruit.

Phenolic Compounds in Chilean Mistletoe (Quintral, Tristerix tetrandus) Analyzed by UHPLC-Q/Orbitrap/MS/MS and Its Antioxidant Properties

Mass spectrometry has become a method of choice to characterize bioactive compounds in biological samples because of its sensitivity and selectivity. Hybrid ultra-HPLC hyphenated with Orbitrap mass analyzer is an innovative state of the art technology that allows fast and accurate metabolomic analyses. In this work the metabolites of a Chilean mistletoe endemic to the VIII region of Chile were investigated for the first time using UHPLC mass analysis (UHPLC-PDA-HESI-Orbitrap MSⁿ). The anthocyanins, together with the non-pigmented phenolics were fingerprinted and correlated with the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics, flavonoids and anthocyanins measured by spectroscopic methods. Six anthocyanins were identified, and among them, the 3-O-glycosides of delphinidin and cyanidin were the major ones. In addition, several phenolic acids (including feruloylquinic acid, feruloyl glucose, chlorogenic acid) and several flavonols (luteolin, quercetin, apigenin, isorhamnetin and glycoside derivatives) were also identified. The mistletoe leaves showed the highest antioxidant activity as measured by the DPPH radical bleaching, ferric reducing antioxidant power and superoxide anion scavenging activity tests (13.38 ± 0.47 µg/mL, 125.32 ± 5.96 µmolTE/g DW and 84.06 ± 4.59 at 100 µg/mL, respectively).

Fast Detection of Phenolic Compounds in Extracts of Easter Pears (Pyrus communis) from the Atacama Desert by Ultrahigh-Performance Liquid Chromatography and Mass Spectrometry (UHPLC-Q/Orbitrap/MS/MS)

A small Chilean variety of pears growing in the town of Toconao, an oasis located at the northeastern edge of the Salar de Atacama, northern Chile, was studied by means of modern PDA and high resolution mass spectral data (UHPLC-PDA-HESI-orbitrap-MS/MS). In addition, the antioxidant features of the fruits were compared with the varieties Packhman’s Triumph and Abate Fetel and correlated with the presence of phenolic compounds. The non-pigmented phenolics were fingerprinted and related to the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics and flavonoids measured by spectroscopic methods. The machine allowed a fast separation of 15 min employing a flow rate of 1 mL per minute and could accurately identify 25 compounds, including several isorhamnetin derivatives and phenolic acids, present in the peel and pulps of this Chilean variety for the first time. The compounds were monitored using a wavelength range of 210–800 nm. The native small Chilean pear showed the highest antioxidant activity measured as the bleaching of the DPPH radical, the ferric reducing antioxidant power and superoxide anion scavenging activity (8.61 ± 0.65 μg/mL, 712.63 ± 12.12 micromols trolox equivalents (μmol/TE)/100 g FW, and 82.89% ± 2.52% at 100 μg/mL, respectively).

Antibacterial Activity, Antioxidant Effect and Chemical Composition of Propolis from the Región del Maule, Central Chile

Propolis is commercialized in Chile as an antimicrobial agent. It is obtained mainly from central and southern Chile, but is used for the same purposes regardless of its origin. To compare the antimicrobial effect, the total phenolic (TP), the total flavonoid (TF) content and the phenolic composition, 19 samples were collected in the main production centers in the Región del Maule, Chile. Samples were extracted with MeOH and assessed for antimicrobial activity against Gram (+) and Gram (−) bacteria. TP and TF content, antioxidant activity by the DPPH, FRAP and TEAC methods were also determined. Sample composition was assessed by HPLD-DAD-ESI-MS/MS. Differential compounds in the samples were isolated and characterized. The antimicrobial effect of the samples showed MICs ranging from 31.5 to > 1000 µg/mL. Propolis from the central valley was more effective as antibacterial than those from the coastal area or Andean slopes. The samples considered of interest (MIC ≤ 62.5 µg/mL) showed effect on Escherichia coli, Pseudomonas sp., Yersinia enterocolitica and Salmonella enteritidis. Two new diarylheptanoids, a diterpene, the flavonoids pinocembrin and chrysin were isolated and elucidated by spectroscopic and spectrometric means. Some 29 compounds were dereplicated by HPLC-MS and tentatively identified, including nine flavones/flavonol derivatives, one flavanone, eight dihydroflavonols and nine phenyl-propanoids. Propolis from the Región del Maule showed large variation in antimicrobial effect, antioxidant activity and composition. So far the presence of diarylheptanoids in samples from the coastal area of central Chile can be considered as a marker of a new type of propolis.

Mechanistic evidence of Passiflora edulis (Passifloraceae) anxiolytic activity in relation to its metabolite fingerprint as revealed via LC-MS and chemometrics

Passiflora edulis Sims F. flavicarpa along with several other plants belonging to the genus Passiflora have been reported as sedatives and for treatment or prevention of central disorders. This study evaluated the anxiolytic effect of P. edulis ethanol extract and its fractions (viz. chloroform, ethyl acetate and butanol) using the elevated plus-maze model of anxiety and assessment of γ-aminobutyric acid levels. The results revealed that butanol and chloroform extracts exhibit the strongest effect followed by ethyl acetate suggesting that a combination of different classes of metabolites is likely to mediate for P. edulis anxiolytic effect in these fractions. To further pinpoint bioactive agents in fractions, ultra-performance liquid chromatography (UPLC) coupled to high resolution qTOF-MS was used for secondary metabolite profiling. A total of 65 metabolites were characterized including O-flavonoids, C-flavonoids, cyanogenic glycosides and fatty acids. Harman type alkaloids found in P. incarnata were not detected in P. edulis ethanol extract or any of its fractions suggesting that they do not mediate for its CNS modulating effects. Multivariate data analysis (PCA) was further applied to identify metabolite markers for fractions and revealed that enrichment of C-glycoside type flavonoids in chloroform/ethyl acetate fractions versus the exclusive presence of cyanogenic glycosides in its butanol fraction.

Phenolic profiling of the South American "Baylahuen" tea (Haplopappus spp., Asteraceae) by HPLC-DAD-ESI-MS

The aerial parts of several Haplopappus species (Asteraceae), known under the common name "baylahuen", are used as herbal teas in Chile and Argentina. In Chile, "baylahuen" comprises H. multifolius, H. taeda, H. baylahuen and H. rigidus. Little is known about the chemical identity of the infusion constituents in spite of widespread consumption. The aim of the present work was the characterization of phenolics occurring in the infusions and methanol extracts of "baylahuen" by HPLC-DAD-ESI-MS. A simple HPLC-DAD-ESI-MS method was developed for the fast identification and differentiation of Haplopappus spp. used as a tea source, based on the phenolics from the tea and methanol extracts. Some 27 phenolics were tentatively identified in the infusions and methanol extract, including 10 caffeoyl quinic and feruloyl quinic acid derivatives and 17 flavonoids. The HPLC patterns of the Haplopappus tea and methanol extract allow a clear differentiation at the species level. The occurrence of hydroxycinnamic acid derivatives and flavonoids can explain the reputed nutraceutical and health beneficial properties of this herbal tea.

Antioxidant properties and hyphenated HPLC-PDA-MS profiling of Chilean Pica mango fruits (Mangifera indica L. Cv. piqueño)

Antioxidant capacities and polyphenolic contents of two mango cultivars from northern Chile, one of them endemic of an oasis in the Atacama Desert, were compared for the first time. Twenty one phenolic compounds were detected in peel and pulp of mango fruits varieties Pica and Tommy Atkins by HPLC-PDA-MS and tentatively characterized. Eighteen compounds were present in Pica pulp (ppu), 13 in Pica peel (ppe) 11 in Tommy Atkins pulp (tpu) and 12 in Tommy Atkins peel (tpe). Three procyanidin dimers (peaks 6, 9 and 10), seven acid derivatives (peaks 1–4, 11, 20 and 21) and four xanthones were identified, mainly mangiferin (peak 12) and mangiferin gallate, (peak 7), which were present in both peel and pulp of the two studied species from northern Chile. Homomangiferin (peak 13) was also present in both fruit pulps and dimethylmangiferin (peak 14) was present only in Tommy pulp. Pica fruits showed better antioxidant capacities and higher polyphenolic content (73.76/32.23 µg/mL in the DPPH assay and 32.49/72.01 mg GAE/100 g fresh material in the TPC assay, for edible pulp and peel, respectively) than Tommy Atkins fruits (127.22/46.39 µg/mL in the DPPH assay and 25.03/72.01 mg GAE/100 g fresh material in the TPC assay for pulp and peel, respectively). The peel of Pica mangoes showed also the highest content of phenolics (66.02 mg/100 g FW) measured by HPLC-PDA. The HPLC generated fingerprint can be used to authenticate Pica mango fruits and Pica mango food products.

Techniques for analysis of plant phenolic compounds

Phenolic compounds are well-known phytochemicals found in all plants. They consist of simple phenols, benzoic and cinnamic acid, coumarins, tannins, lignins, lignans and flavonoids. Substantial developments in research focused on the extraction, identification and quantification of phenolic compounds as medicinal and/or dietary molecules have occurred over the last 25 years. Organic solvent extraction is the main method used to extract phenolics. Chemical procedures are used to detect the presence of total phenolics, while spectrophotometric and chromatographic techniques are utilized to identify and quantify individual phenolic compounds. This review addresses the application of different methodologies utilized in the analysis of phenolic compounds in plant-based products, including recent technical developments in the quantification of phenolics.