Guayusa (Ilex guayusa L.) new tea: phenolic and carotenoid composition and antioxidant capacity

Acute, dose-response effects of guayusa leaf extract on mood, cognitive and motor-cognitive performance, and blood pressure, heart rate, and ventricular repolarization

PURPOSE

We conducted a randomized, double-blind, placebo-controlled crossover trial in young adults to examine the dose-dependent (600 mg versus 1200 mg), acute effects of consumption of an Ilex guayusa tea extract (GLE) on mood, cognitive and motor-cognitive performance, as well as its acute cardiovascular effects.

METHODS

Twenty-five adults (mean ± SD, age = 28 ± 7 y; 9 M/16 F) completed familiarization and then three randomly ordered experimental visits where they consumed either 600 mg (GLE600) or 1200 mg (GLE1200) GLE or placebo (PLA). Following supplement consumption, participants completed a mood state survey, assessments of perceived jitteriness, energy, and focus, and neurocognitive and motor-cognitive testing. Blood pressure (BP), heart rate, and QT interval length were determined before and after supplementation.

RESULTS

GLE600 significantly improved total mood disturbance (mean ± SE difference = -6.9 ± 2.6 au, p = 0.034), fatigue-inertia (-2.84 ± 0.89 au, p = 0.008), perceived energy (+13.00 ± 4.49 au; p = 0.02), motor speed (+4.52 ± 1.42 au, p = 0.008), and psychomotor speed (+7.20 ± 2.16 au, p = 0.005) relative to PLA. GLE1200 also improved psychomotor speed (+5.08 ± 2.16 ms, p = 0.045) and uniquely increased motor-cognitive performance as reflected by a decrease in reaction time (-0.106 ± 0.04 ms, p = 0.026) during a neurocognitive hop test. The effect of GLE on jitteriness was both dose- and sex-dependent. Jitteriness increased with increasing GLE dose in women only (p < 0.001). Both GLE600 and GLE1200 similarly increased systolic and diastolic BP by 4-5 mmHg (p ≤ 0.022). Neither GLE600 nor GLE1200 acutely influenced QTc length (p = 0.31).

CONCLUSIONS

The goal of GLE supplementation should be considered when selecting a dosing strategy. Lower dosages of GLE (e.g. 600 mg) appear to optimize cognitive and mood-related outcomes while limiting side-effects such as jitteriness in women, and higher dosages may be necessary (e.g. 1200 mg) to promote improvements in motor-cognitive performance.

Exploring the Impact of Infusion Parameters and In Vitro Digestion on the Phenolic Profile and Antioxidant Capacity of Guayusa (Ilex guayusa Loes.) Tea Using Liquid Chromatography, Diode Array Detection, and Electrospray Ionization Tandem Mass Spectrometry

Guayusa tea is derived from the leaves of the Ilex guayusa Loes. plant, which is native to the Amazon rainforest. Beyond its pleasant sensory properties, Guayusa tea is rich in antioxidants, phenolics, and minerals. In this study, the effects of infusion time, temperature, and solvent conditions on the color, antioxidant capacity, total phenolic content, phenolic profile, and antimicrobial activity of Guayusa (Ilex guayusa Loes.) tea were investigated. Guayusa tea samples were prepared using two different solvents, ethanol and water, with 4, 6, and 8-h infusions at 60 and 70 °C. Liquid chromatography, diode array detection, and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MS/MS) were used to determine a comprehensive profile of phenolic compounds and to detect differences due to infusion conditions. Moreover, after the Guayusa tea infusion with the highest bioactive properties was determined, the effects of in vitro gastrointestinal digestion on the total phenolic content, antioxidant capacity, and phenolic compounds of the Guayusa tea infusion were measured. Phenolic profile analysis identified 29 compounds, among which chlorogenic acid and its derivatives were predominant. The increase in infusion time was correlated with an elevation in total phenolic content. Significant differences were observed between water and ethanol infusions of Guayusa in terms of phenolics and antioxidants. The total amount of phenolic compounds in the samples prepared with both solvents was found to increase after oral intake, depending on the digestion stage; meanwhile, the amounts of flavonoid compounds and di-O-caffeoylquinic acid derivatives decreased during digestion.

Green-based methods to obtain bioactive compounds from Ilex guayusa Loes. using polar solvent

Many biological activities have been reported for the Ilex genus. However, few studies in the literature have reported on guayusa. To address this gap in our knowledge, chemical analysis of guayusa leaves was made. Extracts were obtained by applying Soxhlet, maceration, supercritical CO2 and pressurised liquid extraction techniques, using water and ethanol as solvent/cosolvent. Extracts were evaluated for their phenolic content and antioxidant capacity. The chemical profile was obtained from HPLC. In raw guayusa leaves were identified caffeine (2.27 ± 0.05%), protein (15.31 ± 0.07%) and lipids (11.81 ± 0.14%). Extracts presented the highest phenolic content (156.56 ± 1.32 mg GAE g-1) and the best antioxidant activity (EC50= 61.85 ± 0.21 µg mL-1) when water was used as solvent/cosolvent. Through HPLC, three main substances were determined and quantified in the extracts: caffeine, theobromine and 5-caffeoylquinic acid. Based on these results, guayusa may be considered a natural source of compounds with potential application in the food and pharmaceutical industries.

Utilization of the Hollies (Ilex L. spp.): A Review

The hollies (Ilex L., Aquifoliaceae) form a large (>669 spp.) genus of forest trees and shrubs, which is almost cosmopolitan in mesic environments but most diverse in subtropical China and montane South America. Throughout the range of the genus, Ilex species have been utilized as beverages, medicines, ornamentals, honey plants, timber, and for various other minor uses. Recent studies on the genomics, evolution, and biogeography of Ilex now make it possible to take a systematic approach to understanding and expanding the economic importance of the genus, but information on existing uses is scattered among numerous published and unpublished sources. We therefore review the existing literature on utilization of Ilex species, supplementing this with information from the grey literature and product websites. We show that, despite the number and diversity of known uses, most Ilex species are not known to be utilized at present, suggesting considerable unrealized potential. We highlight gaps in our knowledge and opportunities for expanded usage. Finally, we discuss how the availability of a new phylogeny and whole genome can assist screening of additional wild species for economic potential and facilitate breeding programs for species already under cultivation.

Pharmacology and Phytochemistry of Ecuadorian Medicinal Plants: An Update and Perspectives

The use of plants as therapeutic agents is part of the traditional medicine that is practiced by many indigenous communities in Ecuador. The aim of this study was to update a review published in 2016 by including the studies that were carried out in the period 2016–July 2021 on about 120 Ecuadorian medicinal plants. Relevant data on raw extracts and isolated secondary metabolites were retrieved from different databases, resulting in 104 references. They included phytochemical and pharmacological studies on several non-volatile compounds, as well as the chemical composition of essential oils (EOs). The tested biological activities are also reported. The potential of Ecuadorian plants as sources of products for practical applications in different fields, as well the perspectives of future investigations, are discussed in the last part of the review.

Effect of Cocoa Bean Shell Addition on Metabolite Profile and Antioxidant Activity of Herbal Infusions

Cocoa bean shell (CBS) is a by-product with aromatic characteristics that can enhance the aroma and bioactivity of herbal infusions. This study was aimed to determine the effect of the addition of cocoa bean shell on the metabolite profile and antioxidant activity of infusions made with Ilex guayusa and Vernonanthura patens and their mixtures. Metabolite profile was analyzed by gas chromatography–mass spectrometry combined with multivariate analysis. Total polyphenol content and flavonoids were determined by the Folin-Ciocalteu method and by the flavonoid-AlCl3 complex, respectively. Antioxidant activities were measured by the decolorization assay of the 2,2-diphenyl-1-picrylhydrazyl radical and the ferric reducing antioxidant power. The results revealed that the addition of CBS increases the content of phenolic acids in the infusions (caffeic acid, 4-hydroxybenzoic acid, and pyrocatechol). Nonetheless, the antioxidant activity of the infusions decreased with the addition of CBS (16.21 to 2.74 TEAC). Carboxylic acids and derivatives, major compounds present in the infusions prepared with V. patens, were the metabolites that showed the highest correlation with the antioxidant activity. This study suggests that the infusions made with CBS present a profile of metabolites different from the infusions of I. guayusa, V. patens, and their mixtures.

Effect of solvent-solvent partition on antioxidant activity and GC-MS profile of Ilex guayusa Loes. leaves extract and fractions

The use of guayusa (Ilex guayusa Loes.) leaves as functional food has increase recently. This work discusses the antioxidant activity and volatile compounds of guayusa leaves extract and fractions. The methanol crude extract was obtained by maceration, subsequently hexane, chloroform, ethyl acetate, and aqueous fractions were collected by solvent-solvent partition. Total phenolic content (TPC), total flavonol/flavone content (TFC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and ferric reducing antioxidant power (FRAP) were measured by ultraviolet-visible (UV-Vis) spectrophotometry. The results revealed that ethyl acetate fraction showed highest inhibition against DPPH radical (93.86 ± 0.95%) at 500 µg/mL, and reduce the ferric-tripyridyltriazine complex (Fe³⁺-TPTZ) at 1619.81 mg trolox equivalent (TE)/g, followed by aqueous fraction. This bioactivity could be related to phenolic acids, flavones and flavonols content, as well as the caffeine, dodecanoic acid isopropyl ester, caffeic acid, and malic acid identified by gas chromatography-mass spectrometry (GC-MS). These findings support the antioxidant properties of this plant material.

Optimisation of ultrasound-assisted extraction of phenolic antioxidants from Ilex guayusa Loes. leaves using response surface methodology

The present study carried out the optimisation of the total polyphenol content (TPC) extraction assisted by ultrasound in Ilex guayusa leaves applying response surface methodology (RSM). Also, the evaluation of the antioxidant activity of the extract obtained under the optimal extraction conditions was performed. The effect of the variables like, time of sonication, temperature, ethanol/water ratio and solid/liquid relationship and the interactions between them were analysed through the use of a factorial design 2ˆ4. The significant factors were considered for the optimisation, employing a Box-Behnken Design, and the TPC as response variables. It was found that a quadratic model was adequate, with an adjusted R² value of 0.9367. The optimal conditions proposed, by the response surface model were: an extraction temperature of 60 °C, sonication time of 29.9 min and ethanol/water ratio of 76.8/23.2. The optimised leaves extract of I. guayusa show a TPC of 3.46 (±0.17) g gallic acid equivalents/100 g d.w. Radical scavenger activity of the obtained extract at optimum conditions, was performed through the FRAP and ABTS methods, given as result: 0.080 mmol TROLOX equivalents/100 g d.w. and 40.71 μmol TROLOX equivalents/g d.w., respectively. Due to the present findings, I. guayusa extracts can be proposed as a promising component for functional beverages, cosmetic and pharmaceutical formulation.

Bioactive triterpenoids from the caffeine-rich plants guayusa and maté

Unlike all other caffeinated plants, guayusa (Ilex guayusa Loes.) and maté (Ilex paraguariensis A. St. Hill) contain high amounts of pentacyclic triterpenoid acids and alcohols. A phytochemical investigation on these plants revealed a similar triterpenoid profile and a content of ursolic acid (0.7-1%) and amyrin esters (up to 0.5%), quite unusual for dietary plants. The major constituent of the amyrin complex from both plants is α-amyrin palmitate (2a), accompanied by lower amounts of its corresponding palmitoleate (2b) and by the corresponding constitutional isomers from the β-series (3a and 3b, respectively). Ursolic acid (1) was identified as the responsible for the activity of maté and guayusa extracts in the activation of TGR5, a nuclear receptor of relevance for the prevention and management of diabetes and metabolic syndrome because of its involvement in the regulation of energy expenditure and insulin sensitivity.

Health Benefits of Bioactive Compounds from the Genus Ilex, a Source of Traditional Caffeinated Beverages

Tea and coffee are caffeinated beverages commonly consumed around the world in daily life. Tea from Camellia sinensis is widely available and is a good source of caffeine and other bioactive compounds (e.g., polyphenols and carotenoids). Other tea-like beverages, such as those from the genus Ilex, the large-leaved Kudingcha (Ilex latifolia Thunb and Ilex kudingcha C.J. Tseng), Yerba Mate (Ilex paraguariensis A. St.-Hil), Yaupon Holly (Ilex vomitoria), and Guayusa (Ilex guayusa Loes) are also traditional drinks, with lesser overall usage, but have attracted much recent attention and have been subjected to further study. This review summarizes the distribution, composition, and health benefits of caffeinated beverages from the genus Ilex. Plants of this genus mainly contain polyphenols and alkaloids, and show diverse health benefits, which, as well as supporting their further popularization as beverages, may also lead to potential applications in the pharmaceutical or nutraceutical industries.

Antioxidant and anti-inflammatory properties of Ilex guayusa tea preparations: a comparison to Camellia sinensis teas

Ilex guayusa tea preparations are now commercially available as Runa tea. Little is known regarding the antioxidant and anti-inflammatory bioactivities of this tea. The I. guayusa teas had a total polyphenolic content between 54.39 and 67.23 mg GAE per g dry mass and peroxyl radical scavenging capacities between 1773.41 and 2019 μmol TE per g dry mass, nearly half of that for the Camellia sinensis teas. The I. guayusa teas afforded 60-80% protection from oxidative stress in the Caco-2 cellular antioxidant assay, comparable to the C. sinensis teas. The anti-inflammatory activity in lipopolysaccharide-stimulated RAW 264.7 cells of I. guayusa teas was similarly comparable to the C. sinensis teas with nitric oxide production reduced by 10-30%. Major compounds identified by mass spectrometry were the phenolic mono- and dicaffeoylquinic acid derivatives. I. guayusa teas are a good source of dietary phenolic compounds with cellular antioxidant and anti-inflammatory properties.

Changes in phytochemical composition, bioactivity and in vitro digestibility of guayusa leaves (Ilex guayusa Loes.) in different ripening stages

BACKGROUND

Guayusa (Ilex guayusa Loes.) leaves, native of the Ecuadorian Amazon, are popularly used for preparing teas. This study aimed to assess the influence of leaf age on the phenolic compounds and carotenoids and the bioactivity and digestibility (in vitro) of aqueous and hydroalcoholic leaf extracts.

RESULTS

In total, 14 phenolic compounds were identified and quantified. Chlorogenic acid and quercetin-3-O-hexose were the main representatives of the hydroxycinnamic acids and flavonols respectively. Seven carotenoids were quantified, lutein being the main compound. Ripening affected phenolic content significantly, but there was no significant difference in carotenoid content. Antioxidant capacity, measured by the DPPH^• method, was also significantly affected by leaf age. The measurement of in vitro digestibility showed a decrease in phenolic content (59%) as well as antioxidant capacity, measured by the ABTS^•+ method, in comparison with initial conditions of the guayusa infusion. Antibacterial and anti-inflammatory activities were assayed with young leaves owing to their higher phenolic contents. Guayusa did not show any antibacterial activity against Escherichia coli ATCC 25922 or Staphylococcus aureus ATCC 25923. Finally, the hydroalcoholic and aqueous extracts exhibited high in vitro anti-inflammatory activity (>65%).

CONCLUSION

Young guayusa leaves have potential applications as a functional ingredient in food and pharmaceutical industries. © 2017 Society of Chemical Industry.

Regulation of Banana Phytoene Synthase (MaPSY) Expression, Characterization and Their Modulation under Various Abiotic Stress Conditions

Phytoene synthase (PSY) is a key regulatory enzyme of carotenoid biosynthesis pathway in plants. The present study examines the role of PSY in carotenogenesis and stress management in banana. Germplasm screening of 10 Indian cultivars showed that Nendran (3011.94 μg/100 g dry weight) and Rasthali (105.35 μg/100 g dry weight) contained the highest and lowest amounts of β-carotene, respectively in ripe fruit-pulp. Nendran ripe pulp also showed significantly higher antioxidant activity as compared to Rasthali. Meta-analysis of three banana PSY genes (MaPSY1, MaPSY2, and MaPSY3) was performed to identify their structural features, subcellular, and chromosomal localization in banana genome. The distinct expression patterns of MaPSY1, MaPSY2, and MaPSY3 genes were observed in various tissues, and fruit developmental stages of these two contrasting cultivars, suggesting differential regulation of the banana PSY genes. A positive correlation was observed between the expression of MaPSY1 and β-carotene accumulation in the ripe fruit-peel and pulp of Nendran. The presence of stress responsive cis-regulatory motifs in promoter region of MaPSY genes were correlated with the expression pattern during various stress (abscisic acid, methyl jasmonate, salicylic acid and dark) treatments. The positive modulation of MaPSY1 noticed under abiotic stresses suggested its role in plant physiological functions and defense response. The amino acid sequence analysis of the PSY proteins in contrasting cultivars revealed that all PSY comprises conserved domains related to enzyme activity. Bacterial complementation assay has validated the functional activity of six PSY proteins and among them PSY1 of Nendran (Nen-PSY1) gave the highest activity. These data provide new insights into the regulation of PSY expression in banana by developmental and stress related signals that can be explored in the banana improvement programs.