Three new flavonoids, proanthocyanidin, and accompanying phenolic constituents from Feijoa sellowiana

TLC-bioautography-guided identification and assessment of the antibacterial compounds from Feijoa sellowiana

INTRODUCTION

A rapid procedure was developed for the targeted isolation and assessment of antibacterial compounds from plant-based materials. The effectiveness of this method was demonstrated using Feijoa sellowiana fruit peels.

OBJECTIVE

The objectives of this study are as follows: develop an efficient procedure utilizing direct thin-layer chromatography (TLC)-bioautography to facilitate the targeting, identification, and purification of antibacterial compounds from plant extracts and delineate a method based on TLC-bioautography to determine the minimum effective dose (MED), alongside a colorimetric broth microdilution aided by high-performance liquid chromatography (HPLC) for evaluating the isolated active compounds.

METHODOLOGY

Active compounds were targeted using TLC-bioautography against Staphylococcus aureus, and the identification was achieved through liquid chromatography-mass spectrometry (LC-MS) combined with Compound Discoverer. Purification was carried out using a customized separation method. The structure was confirmed using nuclear magnetic resonance (NMR) spectroscopy. The MED, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) were determined by two enhanced antibacterial assays.

RESULTS

The main antibacterial compound identified was flavone. A TLC-bioautography-based antibacterial assay and a colorimetric broth microdilution assisted by HPLC were described as the enhanced antibacterial assay protocols. The MED, MIC, and MBC of flavone against S. aureus were found to be 4.2-5.2 μg/cm2, 225-275 μg/mL, and 550-650 μg/mL, respectively. Similarly, the MED, MIC, and MBC against Escherichia coli were determined to be 5.2-6.1 μg/cm2, 325-375 μg/mL, and 375-425 μg/mL, respectively.

CONCLUSION

This study proposed an enhanced bioassay-guided separation technique for the isolation of antibacterial compounds from plants, along with two improved methods for assessing the antibacterial efficacy of insoluble or colored compounds.

Comparison of Different Green Extraction Techniques Used for the Extraction of Targeted Flavonoids from Edible Feijoa (Acca sellowiana (O.Berg) Burret) Flowers

This study aimed to investigate the effect of four green extraction techniques (ultrasound-assisted extraction, UAE; supercritical fluid extraction, SFE; subcritical water extraction, SWE; and extraction using deep eutectic solvents, DES) on the extraction of targeted flavonoids from edible feijoa flowers. The bioactive components in the obtained extracts were quantified by High-Performance Liquid Chromatography-Photodiode Array Detector (HPLC-PDA). Moreover, total polyphenol content and antioxidant activity by DPPH^•, ABTS^•+, FRAP, and CUPRAC assays were investigated. UAE generally gave the highest yields for isoquercitrin and quercetin content (18.36-25.33 and 10.86-16.13 µg/g), while DES extraction with choline chloride:lactic acid (1:2) and H₂O content of 50% gave the highest yield of chrysanthemin (90.81 µg/g). The highest yield of flavone (12.69 mg/g) was obtained with supercritical CO₂ at 300 bar. Finally, UAE gave the highest total polyphenol content (ca. 64 mg GAE/g) and antioxidant activity at 70 °C during 30 min with 40% (0.84 mmol TEAC/g and 2.25 mmol Fe²⁺/g, for ABTS^•+ and CUPRAC, respectively) and 60% ethanol-water solution (0.49 mmol TEAC/g and 2.09 mmol Fe²⁺/g, for DPPH^• and FRAP, respectively). The eco-friendly extraction techniques resulted in selective methods capable of extracting targeted bioactive compounds from edible feijoa flowers.

Antioxidant Activity and Inhibition of Digestive Enzymes of New Strawberry Tree Fruit/Apple Smoothies

In this study, original smoothies obtained with strawberry tree fruit puree and apple juice enriched with Diospyros kaki fruits, Myrtus communis purple berry extract, Acca sellowiana, and Crocus sativus petal juice were evaluated for their antioxidant activity and inhibition of targeted digestive enzymes. Values of CUPRAC, FRAP, ORAC, DPPH•, and ABTS•+ assays generally increased with plant enrichment, particularly for A. sellowiana addition (ABTS•+ 2.51 ± 0.01 mmol Trolox/100 g fw). The same trend was observed regarding the ability to scavenge reactive oxygen species (ROS) tested in Caco-2 cell cultures. Inhibitory activity on α-amylase and α-glucosidase was increased by D. kaki, M. communis, and A. sellowiana. Total polyphenols evaluated by UPLC-PDA analysis ranged between 535.75 ± 3.11 and 635.96 ± 5.21 mg/100 g fw, and A. sellowiana provided the higher amount. Flavan-3-ols accounted for more than 70% of phenolic compounds, and only smoothies enriched with C. sativus showed a high amount of anthocyanins (25.12 ± 0.18 mg/100 g fw). The outcome of this study indicates these original smoothies as a possible ally in counteracting oxidative stress, as established by their favourable antioxidant compound profile, thus suggesting an interesting future application as nutraceuticals.

Chemical Composition, Antiaging Activities and Molecular Docking Studies of Essential Oils from Acca sellowiana (Feijoa)

This study aimed to investigate the chemical composition of essential oils isolated from Acca sellowiana (feijoa) leaves and stems and elaborate on their relevance as natural anti-aging, coupled with molecular-docking studies. The isolated oils were analysed using gas chromatography-mass spectrometry analysis and investigated for inhibitory effects against acetylcholinesterase, β -secretase, collagenase, elastase and tyrosinase. Molecular-modelling study was performed using MOE-Dock program to evaluate binding interactions of major components with the above-mentioned targets. The leaf oil revealed the predominance of caryophyllene oxide (24.3%), linalool (7.9%), and spathulenol (6.6%), while the stem oil was presented by caryophyllene oxide (38.1%), α-zingiberene (10.1%) and humulene oxide II (6.0%). The stem oil expressed superior inhibitory activities against acetylcholinesterase (IC 50 =0.15±0.01µg/mL), β -secretase (IC 50 =3.99±0.23µg/mL), collagenase (IC 50 =408.10±20.80 µg/mL), elastase (IC 50 =0.17±0.01 μg/mL) and tyrosinase (IC 50 =8.45 ± 0.40µg/mL). The valuable binding interactions and docking scores were observed for caryophyllene oxide and α-zingiberene with acetylcholinesterase. Besides, α-zingibirene followed by linalool and τ-cadinol revealed tight fitting with collagenase and elastase. Additionally, linalool, spathulenol and τ-cadinol showed the best binding energy to tyrosinase. This study provides valuable scientific data on A. sellowiana as potential candidates for the development of natural antiaging formulations.

Preparation of Synthetic and Natural Derivatives of Flavonoids Using Suzuki-Miyaura Cross-Coupling Reaction

Herein, we report the use of the Suzuki–Miyaura cross-coupling reaction for the preparation of a library of synthetic derivatives of flavonoids for biological activity assays. We have investigated the reactivity of halogenated flavonoids with aryl boronates and with boronyl flavonoids. This reaction was used to prepare new synthetic derivatives of flavonoids substituted at C-8 with aryl, heteroaryl, alkyl, and boronate substituents. The formation of flavonoid boronate enabled a cross-coupling reaction with halogenated flavones yielding biflavonoids connected at C-8. This method was used for the preparation of natural compounds including C-8 prenylated compounds, such as sinoflavonoid NB. Flavonoid boronates were used for the preparation of rare C-8 hydroxyflavonoids (natural flavonoids gossypetin and hypolaetin). A series of previously unknown derivatives of quercetin and luteolin were prepared and fully characterized.

Do Uncommon Plant Phenolic Compounds Have Uncommon Properties? A Mini Review on Novel Flavonoids

Unique plants and their properties, once considered synonymous to medicine, remain a potent source for new compounds in modern science. Plant polyphenols and natural products continue to be investigated for effective treatments for the most persistent of human ailments. In this review, fifty novel plant phenolic compounds have been compiled and briefly described from the previous five years. Select compounds and notable plant species from genus Morinda and Sophora are further expanded on. Traditional medicine plants often contain rich and diverse mixtures of flavonoids, from which rare compounds should receive attention. The bioactivity of crude plant extracts, purified compounds and mixtures can differ greatly, requiring that these interactions and mechanisms of action be investigated in greater detail. Novel applications of uncommon natural products, namely mimosine and juglone, are explored within this review. The 2019 coronavirus pandemic has resulted in abrupt spike of related scientific publications: speculation is made regarding plant natural products and future of antiviral drug discovery.

Euphorbia characias: Phytochemistry and Biological Activities

The aim of this review is to summarize all the compounds identified and characterized from Euphorbia characias, along with the biological activities reported for this plant. Euphorbia is one of the greatest genera in the spurge family of Euphorbiaceae and includes different kinds of plants characterized by the presence of milky latex. Among them, the species Euphorbia characias L. is an evergreen perennial shrub widely distributed in Mediterranean countries. E. characias latex and extracts from different parts of the plant have been extensively studied, leading to the identification of several chemical components such as terpenoids, sterol hydrocarbons, saturated and unsaturated fatty acids, cerebrosides and phenolic and carboxylic acids. The biological properties range between antioxidant activities, antimicrobial, antiviral and pesticidal activities, wound-healing properties, anti-aging and hypoglycemic properties and inhibitory activities toward target enzymes related to different diseases, such as cholinesterases and xanthine oxidase. The information available in this review allows us to consider the plant E. characias as a potential source of compounds for biomedical research.

Phytochemical profile, enzyme inhibition activity and molecular docking analysis of Feijoa sellowiana O. Berg

Feijoa sellowiana leaves and fruits have been investigated as a source of diverse bioactive metabolites. Extract and eight metabolites isolated from F. sellowiana leaves were evaluated for their enzymatic inhibitory activity against α-glucosidase, amylase, tyrosinase, acetylcholinestrerase and butyrylcholinesterase both in vitro and in silico. Feijoa leaves’ extract showed strong antioxidant activity and variable levels of inhibitions against target enzymes with a strong anti-tyrosinase activity (115.85 mg Kojic acid equivalent/g). Additionally, α-tocopherol emerged as a potent inhibitor of AChE and BChE (5.40 & 10.38 mmol galantamine equivalent/g, respectively). Which was further investigated through molecular docking and found to develop key enzymatic interactions in AChE and BChE active sites. Also, primetin showed good anti BChE (11.70 mmol galantamine equivalent/g) and anti-tyrosinase inhibition (90.06 mmol Kojic acid equivalent/g) which was also investigated by molecular docking studies.

Highlights

Isolation of eight bioactive constituents from Feijoa sellowiana leaves.

In vitro assays using different enzymatic drug targets were investigated.

In silico study was performed to define compound interactions with target proteins.

Feijoa leaf is an excellent source of anti-AChE and antityrosinase bioactives.

Antioxidant and antibacterial compounds from feijoa leaf extracts obtained by pressurized liquid extraction and supercritical fluid extraction

This work investigated the efficiency of pressurized liquid extraction (PLE) and supercritical fluid extraction with cosolvent (SFE) in obtaining feijoa leaf extracts with high antioxidant and antibacterial activities. PLE was performed in customized equipment with environmentally friendly solvents, at 40/80 °C, in dynamic and static mode, and SFE was carried out for 210 min at 30 MPa, 55 °C and 15% ethanol-water as cosolvent. PLE extract (80 °C/ethanol-water/dynamic) provided the highest yield, total phenolic content, and antioxidant activities, but it was not effective as antibacterial agent. In contrast, SFE extract exhibited effectiveness against S. aureus, E. coli, and S. typhimurium, with minimum inhibitory concentration values from 14,211 to 3,553 µg.mL^-1. Finally, gallic acid, catechin and isoquercetin were the major phenolics identified by liquid chromatography. Our findings revealed that feijoa leaf extracts by PLE and SFE have remarkable bioactivity, presenting a great potential to be used as natural food additives.

Proliferative and Regenerative Effect of Acetonic Extract of Feijoa sellowiana on Stem Cells

BACKGROUND

Feijoa is widely used in medicine due to their anti-inflammatory, antioxidant, antimicrobial and antitumor properties. The current investigation studied the proliferative and regenerative effect of acetonic extract of Feijoa sellowiana on stem cells.

METHODS

Acetone extract of Feijoa was prepared using percolator and rotary machines. Human bone marrow stem cells (hBMSCs) were used as experimental in vitro model and characterized morphologically, by flowcytometry, and differentiation properties. The toxicity of the extract on hBMSCs was determined by MTT assay. The viability and growth kinetics of hBMSCs treated to Feijoa was determined. Real time PCR was used for changes in expression of proliferative and apoptotic genes on day 7^th.

RESULTS

MTT assay demondtrated that Feijoa at doses less than 200 ng/ml did not show any cytotoxic effect on hBMSCs and increased the cell proliferation until day 3^rd followed by a non-significant slow decreasing trend until day 7^th. Population doubling time (PDT) showed a decline until day 3^rd followed by an increase until day 7^th. A significant rise in expression of Bax and decline in Bcl-2 expression were noted on day 7^th.

CONCLUSION

The modulatory activity of Feijoa may be responsible for its increasing effect on cell proliferation till day 3^rd. Therefore, when faster proliferation during a shorter time period is targeted, Feijoa can be safely added to the culture media in the first three days.

Oxidative Stress, Antioxidant Capabilities, and Bioavailability: Ellagic Acid or Urolithins?

Oxidative stress (OS), triggered by overproduction of reactive oxygen and nitrogen species, is the main mechanism responsible for several human diseases. The available one-target drugs often face such illnesses, by softening symptoms without eradicating the cause. Differently, natural polyphenols from fruits and vegetables possess multi-target abilities for counteracting OS, thus representing promising therapeutic alternatives and adjuvants. Although in several in vitro experiments, ellagitannins (ETs), ellagic acid (EA), and its metabolites urolithins (UROs) have shown similar great potential for the treatment of OS-mediated human diseases, only UROs have demonstrated in vivo the ability to reach tissues to a greater extent, thus appearing as the main molecules responsible for beneficial activities. Unfortunately, UROs production depends on individual metabotypes, and the consequent extreme variability limits their potentiality as novel therapeutics, as well as dietary assumption of EA, EA-enriched functional foods, and food supplements. This review focuses on the pathophysiology of OS; on EA and UROs chemical features and on the mechanisms of their antioxidant activity. A discussion on the clinical applicability of the debated UROs in place of EA and on the effectiveness of EA-enriched products is also included.

Evaluation of the physiological state of feijoa (Feijoa sellowiana Berg) in subtropical Russia

The article presents the results of research examining varietal diversity with respect the activity of oxidative enzymes (EC 1.11.1.6) and the dry matter and Proline accumulation of leaves under optimal and stressful conditions. For feijoa, the most stressful period in the subtropics of Russia, with respect to hydrothermal conditions, occurs between July and September. Studies have shown that the highest degree of enzymatic activity is observed in August in the ‘Superba’ variety of feijoa, which was used as a control in this study, and the lowest level of activity was observed in the 'Sentjabrskaja' variety. The long-term water deficit experienced in September coincides with fruiting in feijoa. This causes a change in catalase activity in leaves, which is maintained until it is inhibited. Form ShV-1 of feijoa is characterised by its metabolic stability. In fact, the activity of oxidative enzymes in leaves of the variety is stable. Dry matter content per unit area increases as the leaf grows. During the drought period, which coincides with active fruiting, the leaves of the ‘Dachnaja' variety and the ShV-1 form accumulate significantly less dry matter than other varieties. In the ‘Dagomysskaja' variety, the intensity of organic matter consumption via respiration and outflow exceeds visible photosynthesis, which is expressed as a negative value (average = 1.96 g.dm-2 h). To fully characterise the physiological state of feijoa plants under the influence of abiotic factors and catalase activity in the humid subtropics of Russia, indicators of dry matter accumulation and true photosynthesis intensity can be used.

Ion-Trap Mass Spectrometric Analysis of Bisphenol A Interactions With Titanium Dioxide Nanoparticles and Milk Proteins

Quantitative analysis of endocrine-disrupting molecules such as bisphenol A (BPA) in freshwater to determine their widespread occurrence in environmental resources has been challenged by various adsorption and desorption processes. In this work, ion trap mass spectrometry (ITMS) analysis of BPA was aimed at studying its molecular interactions with titanium dioxide (TiO2) nanoparticles and milk whey proteins. Addition of sodium formate prevented TiO2 nanoparticles from sedimentation while enhancing the electrospray ionization (ESI) efficiency to produce an abundance of [BPA + Na]+ ions at m/z 251.0. More importantly, the ESI-ITMS instrument could operate properly during a direct infusion of nanoparticles up to 500 μg/mL without clogging the intake capillary. Milk protein adsorption of BPA could decrease the [BPA + Na]+ peak intensity significantly unless the proteins were partially removed by curdling to produce whey, which allowed BPA desorption during ESI for quantitative analysis by ITMS.

Evaluation of Antioxidant Systems and Ascorbate-Glutathione Cycle in Feijoa Edible Flowers at Different Flowering Stages

Background: Feijoa (Acca sellowiana (O. Berg)) was initially introduced as an ornamental plant, but nowadays, it is widely cultivated for the numerous beneficial properties of its edible fruits. Feijoa flowers have been included in the list of edible flowers, but despite this, they are still considered niche products due to consumer skepticism and lack of publicity. Methods: This study evaluated the physicochemical traits, antioxidant system, and ascorbate-glutathione cycle in feijoa flowers at five flowering stages based on the Biologische Bundesanstalt, Bundessortenamt und CHemische Industrie (BBCH) scale. Results: The results showed that the optimal stage to harvest feijoa flower is the F2 stage characterized by high bioactive compounds content. Furthermore, the enzymes involved in oxidative stress and the ascorbate-glutathione cycle showed different trends during the flowering stages. Conclusions: This study provides new evidence to understand the possible role of bioactive compounds and ascorbate-glutathione cycle in the regulation of flower development, defining the optimal stage to harvest flowers.

Evaluation of bioactive compounds and antioxidant capacity of edible feijoa (Acca sellowiana (O. Berg) Burret) flower extracts

Abstract

The research aimed to evaluate the polyphenolic composition and the antioxidant capacity of edible extracts of feijoa (Acca sellowiana (O. Berg) Burret) flowers. Phenolic compounds of whole feijoa flower (FM), feijoa petals (PM) and feijoa petals juice (PJ) were identified by high-performance liquid chromatography coupled with electrospray mass spectrometry and quantified by liquid chromatography coupled with ultraviolet/visible detection. Moreover, the total polyphenol (TP) content was measured spectrophotometrically and the antioxidant capacities of the extracts were evaluated by FRAP, CUPRAC, DPPH^·, and ABTS^·+ assays. The FM showed TP content (395.14 ± 7.91 mg GAE/L) higher than PM and PJ, and exhibited better antioxidant capacities. FM extracts were characterized by the high content of anthocyanins (115.3 ± 3.6 mg/L), flavonols (42.9 ± 3.3 mg/L) and the presence of ellagic acid (7.9 ± 0.2 mg/L) and other galloyltannins. In addition, cyanidin-3-O-glucoside and apigenin were detected in all the three extracts. The present study provided an overview on particular bioactive compounds that characterise different parts of edible feijoa flowers. Among the latter, FM proved to be the most suitable for exploitation in the food and health manufactory.

Graphic abstract

Exploring the Antioxidant Effects and Periodic Regulation of Cancer Cells by Polyphenols Produced by the Fermentation of Grape Skin by Lactobacillus plantarum KFY02

Lactobacillus plantarum KFY02 (LP-KFY02) was isolated from naturally fermented yoghurt in Xinjiang. We previously demonstrated that LP-KFY02 has good biological activity in vitro. In this study, LP-KFY02 was used to ferment grape skin, and the LP-KFY02 fermented grape skin extract solution (KFSE) was examined for its antioxidant ability in a human embryonic kidney (293T) cell oxidative damage model caused by H2O2 and its inhibitory effect on human hepatoma (HepG2) cells. The results showed that KFSE reduced the degree of oxidative damage in 293T cells, increased the relevant expression levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and GSH-peroxidase (GSH-Px), and total antioxidant capacity (T-AOC), and decreased the expression levels of lactate dehydrogenase (LDH), malondialdehyde (MDA), and nitric oxide (NO). The expression of genes and proteins of SOD, CAT, GSH, and GSH-Px was up-regulated. In addition, KFSE-induced growth inhibition appeared to be through induction of cell-cycle arrest. This induction was accompanied by a reduction in the expression of cell-cycle genes, such as cyclin-D1 and CDK4. In addition, KFSE induced gene expression of p21, the apoptosis gene wild-type p53 and the caspase family. At the protein expression level, Bax and Caspase-8 were up-regulated, and the inflammatory marker Nuclear Factor Kappa-B (NF-κB) was down-regulated. The fermentation solution polyphenols were separated and identified as epicatechin gallate, coumarin, new chlorogenic acid, rutin, resveratrol, chlorogenic acid, rosmarinic acid, etc. by HPLC. Overall, these results demonstrate that KFSE significantly attenuated oxidative damage in 293T cells and inhibited tumor growth in HepG2 cancer cells, induces cell-cycle arrest and affects proteins involved in cell-cycle regulation and proliferation. This suggests that KFSE may also be explored as a neo-adjuvant to expansion of hepatoma.

Nutritional Characteristics and Antimicrobial Activity of Australian Grown Feijoa (Acca sellowiana)

The present study determined the chemical composition, bioactive compounds and biological properties of Australian grown feijoa (Acca sellowiana), including whole fruit with peel, fruit peel and pulp, in order to assess the nutritional quality and antimicrobial activity of this emerging subtropical fruit. Polyphenolic compounds and vitamins were determined by UHPLC-PDA-MS/MS, showing that the feijoa fruit not only contains high amounts of antioxidant flavonoids, but is also a valuable source of vitamin C (63 mg/100 g FW (fresh weight)) and pantothenic acid (0.2 mg/100 g FW). Feijoa fruit is also a good source of dietary fibre (6.8 g/100 g FW) and potassium (255 mg/100 g FW). The edible fruit peel possesses significantly (p < 0.05) higher amounts of antioxidant flavonoids and vitamin C than the fruit pulp. This is most likely the reason for the observed strong antimicrobial activity of the peel-extracts against a wide-range of food-spoilage microorganism. The consumption of feijoa fruit can deliver a considerable amount of bioactive compounds such as vitamin C, flavonoids and fibre, and therefore, may contribute to a healthy diet. Furthermore, the potential use of feijoa-peel as a natural food perseverative needs to be investigated in follow-up studies.

Nutritional properties, identification of phenolic compounds, and enzyme inhibitory activities of Feijoa sellowiana leaves

The nutritional values, the identification of individual phenolic compounds as well as the functional properties (in vitro acetylcholinesterase (AChE) and pancreatic lipase inhibition) of Tunisian Feijoa sellowiana (O.Berg) leaves were determined by high-performance liquid chromatography coupled with diode array and mass spectrometry detector. Feijoa Sellowiana  leaves Extract (FSLE) were evaluated in the present work. Macronutrient components (proteins, carbohydrates, dietary fiber, lipids, and ashes) of FSLE as well as their fatty acids and mineral content were determined. The individual phenolic composition was characterized by the presence of flavonols (mostly quercetin glycosides), flavan-3-ols (procyanidins and catechins), and phenolic acid derivatives. To understand the possible inhibition mechanism exerted by the extract components, enzyme kinetic studies using derived Lineweaver-Burk (LB) plots and Michaelis-Menten were performed. The obtained results evidenced that FSLE exhibited important AChE inhibitory effect, behaving as a noncompetitive inhibitor. Furthermore, the leaves' extract inhibited irreversibly the pancreatic lipase, with maximum inhibition (70%) achieved at 1 mg/ml. PRACTICAL APPLICATIONS: In many countries of the world, Feijoa Sellowiana leaves are used as an alternative to tea drinks and as a folkloric medicine. Moreover, it is well known that the phytochemical compounds are a practical alternative for the prevention of many chronic diseases such as Alzheimer's and obesity. For this reason, the present study aimed to evaluate the nutritional, individual phenolic compounds, and functional properties of Feijoa Sellowiana leaves to valorize them as a food and pharmaceutical bioactive human source.

Extraction Optimization, Antioxidant Capacity and Phenolic Profiling of Extracts from Flesh, Peel and Whole Fruit of New Zealand Grown Feijoa Cultivars

Feijoa fruit is becoming increasingly popular, yet limited studies have focused on the antioxidant capacity and phenolic profiling of its extracts. In this research, optimization of phenolic extraction from feijoa flesh, peel, and whole fruit from four New Zealand grown cultivars was conducted using orthogonal design. Antioxidant activities of the extracts were assessed, followed by phenolic profiling by a validated liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method. For feijoa flesh and whole fruit, the extraction was optimized using 70% ethanol, material to solvent ratio of 1:30, at extraction temperature of 50 °C for 30 min. For feijoa peel, extraction at 50 °C for 60 min using 50% ethanol with a material to solvent ratio of 1:30 were the optimized conditions. Results showed feijoa peel had higher total phenolic content (TPC) and antioxidant activities than the flesh and whole fruit. Overall, the Unique cultivar had a relatively higher TPC and antioxidant activity than the other cultivars tested. A total of 15 phenolic compounds were identified, and seven of them were reported for the first time in feijoa fruit. This is the first systematic investigation on the extraction method, phenolic content, antioxidant activity and phenolic profile of feijoa emphasis on comparison of sample types and cultivars.

Modified Supercritical Carbon Dioxide Extraction of Biologically Active Compounds from Feijoa Sellowiana Leaves

For the first time, the modified supercritical carbon dioxide extraction (MSCE) of biologically active compounds from Feijoa sellowiana leaves was investigated. Total yield (TY) and bioactivity of biocompounds in terms of DPPH• (%DPPHsc) and HO• (%HOsc) radicals scavenging were maximized via multivariate optimization. The optimized conditions were the pressure of 272.34 bar, supercritical carbon dioxide flow rate of 1.58 mL min−1, temperature of 52.48 °C, and dynamic extraction time of 110.62 min. The predicted values of the TY, %DPPHsc, and %HOsc were 81.12 mg g−1, 85.16 %, and 75.66 %, respectively. The chromatographic analysis demonstrated gallic acid as the main biophenolic (136.20 ± 0.16 mg g−1). The scanning electron microscopy images showed dramatic disruption of cells treated with MSCE. A comprehensive comparison was made between current findings and other techniques (conventional and ultrasonic waves assisted extraction). More TY was achieved using conventional method but the bioactivity of MSCE products was considerably better.

Screening of Cytotoxicity and Anti-Inflammatory Properties of Feijoa Extracts Using Genetically Modified Cell Models Targeting TLR2, TLR4 and NOD2 Pathways, and the Implication for Inflammatory Bowel Disease

Feijoa has been increasingly studied in the recent decade, while investigations into its bioactivities including anti-inflammatory activity are lacking. In this article, the cytotoxicity and anti-inflammatory properties of feijoa extracts, from flesh, peel and whole fruit, from four cultivars namely APOLLO, UNIQUE, OPAL STAR and WIKI TU are presented. Three inflammatory pathways, Toll-like receptor 2 (TLR2), TLR4 and nucleotide-binding oligomerization domain-containing protein 2 (NOD2), were investigated using genetically modified cell models namely HEK-Blue™ hTLR2, HEK-Blue™ hTLR4, NOD2-WT and NOD2-G908R. Results show that feijoa peel extract induced higher cytotoxicity than flesh and whole fruit extracts, and the APOLLO cultivar was the most anti-inflammatory among the four tested cultivars. The anti-inflammatory activity of feijoa flesh was detected only through the TLR2 pathway, and the activity of feijoa peel and whole fruit was evident mainly through the TLR2 and NOD2 pathways. Most notably, feijoa anti-inflammatory activity was superior to ibuprofen particularly through the TLR2 pathway, with significantly lower secreted embryonic alkaline phosphatase IC50 concentrations (7.88, 12.81, 30.84 and 442.90 μg/mL for APOLLO flesh, peel, whole fruit extract and ibuprofen respectively). These findings indicate that feijoa has great potential to be used in the treatment and prevention of inflammation-related diseases including inflammatory bowel disease.