Isolation of antioxidative secoiridoids from olive wood (Olea europaea L.) guided by on-line HPLC–DAD–radical scavenging detection

Network pharmacology and molecular docking study for biological pathway detection of cytotoxicity of the yellow jasmine flowers

BACKGROUND

The yellow jasmine flower (Jasminum humile L.) is a fragrant plant belonging to the Oleaceae family with promising phytoconstituents and interesting medicinal uses. The purpose of this study was to characterize the plant metabolome to identify the potential bioactive agents with cytotoxic effects and the underlying mechanism of cytotoxic activity.

METHODS

First, HPLC-PDA-MS/MS was used to identify the potential bioactive compounds in the flowers. Furthermore, we assessed the cytotoxic activity of the flower extract against breast cancer (MCF-7) cell line using MTT assay followed by the cell cycle, DNA-flow cytometry, and Annexin V-FITC analyses alongside the effect on reactive oxygen species (ROS). Finally, Network pharmacology followed by a molecular docking study was performed to predict the pathways involved in anti-breast cancer activity.

RESULTS

HPLC-PDA-MS/MS tentatively identified 33 compounds, mainly secoiridoids. J. humile extract showed a cytotoxic effect on MCF-7 breast cancer cell line with IC₅₀ value of 9.3 ± 1.2 µg/mL. Studying the apoptotic effect of J. humile extract revealed that it disrupts G2/M phase in the cell cycle, increases the percentage of early and late apoptosis in Annexin V-FTIC, and affects the oxidative stress markers (CAT, SOD, and GSH-R). Network analysis revealed that out of 33 compounds, 24 displayed interaction with 52 human target genes. Relationship between compounds, target genes, and pathways revealed that J. humile exerts its effect on breast cancer by altering, Estrogen signaling pathway, HER2, and EGFR overexpression. To further verify the results of network pharmacology, molecular docking was performed with the five key compounds and the topmost target, EGFR. The results of molecular docking were consistent with those of network pharmacology.

CONCLUSION

Our findings suggest that J. humile suppresses breast cancer proliferation and induces cell cycle arrest and apoptosis partly by EGFR signaling pathway, highlighting J. humile as a potential therapeutic candidate against breast cancer.

Olive Trees By-Products as Sources of Bioactive and Other Industrially Useful Compounds: A Systematic Review

The need to produce an ever-increasing quantity of material products and food resulting from the planet globalization process has contributed to the spread of modern agriculture based on a linear production resulting in the generation of tons of waste. This huge amount of waste is generally accumulated in landfills, causing different environmental problems. Hence, researchers moved on to study the processes used to recover agro-industrial by-products within a circular and sustainable bio-economy concept. A systematic quest on Scopus and PubMed databases was performed to identify the data available to date on recycling agro-industrial by-products of Olea europaea L. This systematic review summarizes the knowledge regarding the use of olive trees by-products for producing animal feed, biocomposites, bioethanol, cellulose pulp, activated carbon, and as a fuel source for energy production. Furthermore, the data regarding the potential biological activity of extracts from olive roots, wood, bark, and pruning were analyzed. Olive trees by-products are, indeed, rich in molecules with antioxidant, antimicrobial, cardioprotective, and anticancer activity, representing a promising candidate for treat several human diseases.

Selective in vitro cytotoxicity effect of Drimia calcarata bulb extracts against p53 mutant HT-29 and p53 wild-type Caco-2 colorectal cancer cells through STAT5B regulation

Colorectal cancer is the fourth leading cause of oncological-related deaths and the third most diagnosed malignancy, worldwide. The emergence of chemoresistance is a fundamental drawback of colorectal cancer therapies and there is an urgent need for novel plant-derived therapeutics. In this regard, other compounds are needed to improve the efficacy of treatment against colorectal cancer. Medicinal plants have been effectively used by traditional doctors for decades to treat various ailments with little to no side effects. Drimia calcarata (D. calcarata) is one of the plants used by Pedi people in South Africa to treat a plethora of ailments. However, the anticancer therapeutic use of D. calcarata is less understood. Thus, this study was aimed at evaluating the potential anticancer activities of D. calcarata extracts against human colorectal cancer cells. The phytochemical analysis and antioxidant activity were analysed using LC-MS, DPPH, and FRAP. The inhibitory effects and IC50 values of D. calcarata extracts were determined using the MTT assay. Induction of cellular apoptosis was assessed using fluorescence microscopy, the Muse® Cell Analyser, and gene expression analysis by Polymerase Chain Reaction (PCR). Water extract (WE) demonstrated high phenolic, tannin, and flavonoid contents than the methanol extract (ME). LC-MS data demonstrated strong differences between the ME and WE. Moreover, WE showed the best antioxidant activity than ME. The MTT data showed that both ME and WE had no significant activity against human embryonic kidney Hek 293 cell line that served as non-cancer control cells. Caco-2 cells demonstrated high sensitivity to the ME and demonstrated resistance toward the WE, while HT-29 cells exhibited sensitivity to both D. calcarata extracts. The expression of apoptosis regulatory genes assessed by PCR revealed an upregulation of p53 by ME, accompanied by downregulation of Bcl-2 and high expression of Bax after treatment with curcumin. The Bax gene was undetected in HT-29 cells. The methanol extract induced mitochondrial-mediated apoptosis in colorectal Caco-2 and HT-29 cells and WE induced the extrinsic apoptotic pathway in HT-29 cells. ME downregulated STAT1, 3, and 5B in HT-29 cells. The D. calcarata bulb extracts, therefore, contain potential anticancer agents that can be further targeted for cancer therapeutics.

Green Synthesis of Silver Nanoparticles Using Extract of Jasminum officinal L. Leaves and Evaluation of Cytotoxic Activity Towards Bladder (5637) and Breast Cancer (MCF-7) Cell Lines

INTRODUCTION

Jasminum officinale L. is a very important medicinal and industrial flowering aromatic plant.

METHODS

The present study deals with Jasminum officinale L. leaves extract (JOLE) as a reducing and capping agent for the synthesis of silver nanoparticles (AgNPs) by the green pathway. Phenolic profile of the extract was evaluated using HPLC-PDA/MS/MS technique. Jasminum officinale L. leaves extract silver nanoparticles (JOLE-AgNPs) were characterized by ultraviolet light (UV), Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), zeta potential and X-ray diffraction (XRD). JOLE-AgNPs were examined for their cytotoxic activities by neutral red uptake assay (NRU) against bladder (5637) and breast cancer (MCF-7) cell lines.

RESULTS

HPLC-PDA/MS/MS tentatively identified 51 compounds of different chemical classes. UV spectra showed absorption peak at λmax = 363 nm. The biosynthesized AgNPs were predominantly spherical in shape with an average size of 9.22 nm by TEM. The face cubic center (fcc) nature of silver nanoparticles was proved by XRD diffractogram. JOLE-AgNPs exhibited high cytotoxic activity against 5637 and MCF-7 cell lines compared to the cytotoxic activities of JOLE with IC50 of 13.09 µg/mL and 9.3 µg/mL, respectively.

DISCUSSION

The silver nanoparticles formed by Jasminum officinale L. showed high cytotoxic activities against MCF-7 and 5637 cell lines and can be introduced as a new alternative cytotoxic medication.

Nutritional profile and nutraceutical components of olive (Olea europaea L.) seeds

Olive seeds, a potential food by-product from both table olive and olive oil industries, were examined for their overall proximate composition, oil, protein, mineral and phenolic components. Proximate analysis indicates that olive seeds are an unusually rich source of total dietary fibre (≅ 47% dry weight basis, DWB), as well as lipids (≅ 30%) and proteins (≅ 17%). Oil composition shows high levels of oleic (≅ 62% of total fatty acids) and linoleic (≅ 24%) acids, moderate concentrations of tocopherols (≅ 460 mg/kg) and squalene (≅ 194 mg/kg), and relatively high amounts of several sterols and non-steroidal triterpenoids. Olive seed proteins are a rich source of essential amino acids (about 46% of the total AA content). Olive seeds also contain significant amounts of some essential macro-elements (K, Ca, Mg, Na, P) and micro-elements (Zn, Mn, Cu). Phenolic compounds are present at relatively high quantities (≅ 2.8 mg/g seed, DWB); the most abundant belong to the group of secoiridoid compounds (elenolic acid derivatives) including oleuropein and structurally related substances (demethyloleuropein and ligstroside), and nüzhenide derivatives. Based on the general nutritional profile and nutraceutical components, olive seeds have value-added potential as a source of edible oil, proteins or meal serving as feed supplements.

Gene Source Screening as a Tool for Naringenin Production in Engineered Saccharomyces cerevisiae

Flavonoids are plant secondary metabolites with great potential in the food industry. Metabolic engineering of Saccharomyces cerevisiae is a sustainable production technique. However, the current naringenin production yield is low because of inefficient enzymatic activity. Hence, this study uses gene source screening as a tool to identify the best gene source for enzymes such as 4-coumarate: coenzyme ligase (4CL) and chalcone synthase (CHS). For the first time, the 4CL gene from Medicago truncatula and the CHS gene from Vitis vinifera were expressed in S. cerevisiae, and this combination provided the highest yield of naringenin, which was 28-fold higher as compared to the reference strain. The combinations obtained similar performance in the Y-28 strains, where the highest production was 28.68 mg/L. Our results demonstrated that the selection and combination of enzymes from the correct gene source could greatly improve naringenin production. For the future, this could help commercialize flavonoid production, which would result in natural food preservatives and additives.

Ultrasound-Assisted Extraction as a First Step in a Biorefinery Strategy for Valorisation of Extracted Olive Pomace

Currently, interest in finding new feedstock as sources of natural food antioxidants is growing. The extracted olive pomace (EOP), which is an agro-industrial residue from the olive pomace extracting industries, is generated yearly in big amounts, mainly in the Mediterranean countries. EOP was subjected to an ultrasound assisted extraction with ethanol-water mixtures. The effect of main parameters, such as ethanol concentration (30–70% v/v), ultrasound amplitude (20–80%), and extraction time (5–15 min), on the extraction of antioxidant compounds was evaluated according to a Box–Behnken experimental design. The antioxidant capacity of the resulting extracts was determined by measuring their content in total phenolic compounds (TPC) and flavonoids (TFC), as well as their antioxidant activity by DPPH, ferric reducing antioxidant power (FRAP), and ABTS assays. Considering the simultaneous maximization of these five responses, the optimal conditions were found to be 43.2% ethanol concentration, 70% amplitude, and 15 min. The ultrasound assisted extraction of EOP under these optimized conditions yielded an extract with a phenolic and flavonoid content (per gram of EOP) of 57.5 mg gallic acid equivalent (GAE) and 126.9 mg rutin equivalent (RE), respectively. Likewise, the values for DPPH, ABTS, and FRAP assay (per gram of EOP) of 56.7, 139.1, and 64.9 mg Trolox equivalent, respectively were determined in the optimized extract.

Optimization of ultrasound-assisted extraction of biomass from olive trees using response surface methodology

Olive tree pruning biomass (OTP) and olive mill leaves (OML) are the main residual lignocellulosic biomasses that are generated from olive trees. They have been proposed as a source of value-added compounds and biofuels within the biorefinery concept. In this work, the optimization of an ultrasound-assisted extraction (UAE) process was performed to extract antioxidant compounds present in OTP and OML. The effect of the three parameters, ethanol/water ratio (20, 50, 80% of ethanol concentration), amplitude percentage (30, 50, 70%) and ultrasonication time (5, 10, 15 min), on the responses of total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activities (DPPH, ABTS and FRAP) were evaluated following a Box-Behnken experimental design. The optimal conditions obtained from the model, taking into account simultaneously the five responses, were quite similar for OTP and OML, with 70% amplitude and 15 min for both biomasses and a slight difference in the optimum concentration of ethanol. (54.5% versus 51.3% for OTP and OML, respectively). When comparing the antioxidant activities obtained with OTP and OML, higher values were obtained for OML (around 40% more than for OTP). The antioxidant activities reached experimentally under the optimized conditions were 31.6 mg of TE/g of OTP and 42.5 mg of TE/g of OML with the DPPH method, 66.5 mg of TE/g of OTP and 95.9 mg of TE/g of OML with the ABTS method, and 36.4 mg of TE/g of OTP and 49.7 mg of TE/g of OML with the FRAP method. Both OTP and OML could be a potential source of natural antioxidants.

On-line screening and identification of free radical scavenging compounds in Angelica dahurica fermented with Eurotium cristatum using an HPLC-PDA-Triple-TOF-MS/MS-ABTS system

Eurotium cristatum, a beneficial fungus isolated from Fuzhuan tea, was used to ferment Angelica dahurica for the first time. The antioxidant capacities of the extracts before and after fermentation were compared using ABTS, DPPH and FRAP assays. The results showed that the antioxidant capacities of the extracts acquired using organic solvents were greater after fermentation. Moreover, based on a comparison of the HPLC chromatograms, the chemical composition of Angelica dahurica changed substantially during fermentation. To further understand the changes in its antioxidant constituents, an on-line HPLC-PDA-Triple-TOF-MS/MS-ABTS system was employed. Twelve antioxidants belonging to three different classes were detected and identified, and their antioxidant capacities were preliminarily evaluated. The results indicated that the substances produced during the fermentation of Eurotium cristatum played important roles in enhancing the antioxidant capacity.

Ash leaf metabolomes reveal differences between trees tolerant and susceptible to ash dieback disease

European common ash, Fraxinus excelsior, is currently threatened by Ash dieback (ADB) caused by the fungus, Hymenoscyphus fraxineus. To detect and identify metabolites that may be products of pathways important in contributing to resistance against H. fraxineus, we performed untargeted metabolomic profiling on leaves from five high-susceptibility and five low-susceptibility F. excelsior individuals identified during Danish field trials. We describe in this study, two datasets. The first is untargeted LC-MS metabolomics raw data from ash leaves with high-susceptibility and low-susceptibility to ADB in positive and negative mode. These data allow the application of peak picking, alignment, gap-filling and retention-time correlation analyses to be performed in alternative ways. The second, a processed dataset containing abundances of aligned features across all samples enables further mining of the data. Here we illustrate the utility of this dataset which has previously been used to identify putative iridoid glycosides, well known anti-herbivory terpenoid derivatives, and show differential abundance in tolerant and susceptible ash samples.

RP-HPLC-DAD-ESI-QTOF-MS based metabolic profiling of the potential Olea europaea by-product "wood" and its comparison with leaf counterpart

INTRODUCTION

Olea europaea L. organs such as leaves, stems and roots have been associated with numerous in vivo and in vitro biological activities and used for traditional medicinal purposes. However, tree wood is an untapped resource with little information about their chemical composition.

OBJECTIVE

That is why, the objective of this study is to increase the knowledge about phytochemicals from 'Chemlali' olive wood by means of mass spectrometry-based analyses. Its comparison with by-products derived from leaves was also studied.

METHODOLOGY

Hydromethanol extracts from wood and leaves with stems of 'Chemlali' olive cultivar were analysed using reversed-phase (RP) high-performance liquid chromatography (HPLC) coupled to two detection systems: diode-array detection (DAD) and quadrupole time-of-flight (QTOF) mass spectrometry (MS) in negative ion mode. Tandem MS experiments were performed to establish the chemical structure of olive phytochemicals.

RESULTS

A total of 85 compounds were characterised in the studied olive parts and classified as: sugars (3), organic acids (5), one phenolic aldehyde, simple phenolic acids (6), simple phenylethanoids (5), flavonoids (14), coumarins (3), caffeoyl phenylethanoid derivatives (6), iridoids (5), secoiridoids (32), and lignans (5). To our knowledge, the major part of these metabolites was not previously reported in olive tree wood, and 10 olive chemical constituents were identified for the first time in the Oleaceae family.

CONCLUSION

The results presented here demonstrated the usefulness of the methodology proposed, based on RP-HPLC-DAD-ESI-QTOF-MS and MS/MS, to develop an exhaustive metabolic profiling and to recover new biologically active compounds in olive wood with pharmacologic and cosmetic potential. Copyright © 2017 John Wiley & Sons, Ltd.

AMPK modulatory activity of olive-tree leaves phenolic compounds: Bioassay-guided isolation on adipocyte model and in silico approach

Scope

Olive-tree polyphenols have demonstrated potential for the management of obesity-related pathologies. We aimed to explore the capacity of Olive-tree leaves extract to modulate triglyceride accumulation and AMP-activated protein kinase activity (AMPK) on a hypertrophic adipocyte model.

Methods

Intracellular triglycerides and AMPK activity were measured on the hypertrophic 3T3-L1 adipocyte model by AdipoRed and immunofluorescence microscopy, respectively. Reverse phase high performance liquid chromatography coupled to time-of-flight mass detection with electrospray ionization (RP-HPLC-ESI-TOF/MS) was used for the fractionation of the extract and the identification of the compounds. In-silico molecular docking of the AMPK alpha-2, beta and gamma subunits with the identified compounds was performed.

Results

Olive-tree leaves extract decreased the intracellular lipid accumulation through AMPK-dependent mechanisms in hypertrophic adipocytes. Secoiridoids, cinnamic acids, phenylethanoids and phenylpropanoids, flavonoids and lignans were the candidates predicted to account for this effect. Molecular docking revealed that some compounds may be AMPK-gamma modulators. The modulatory effects of compounds over the alpha and beta AMPK subunits appear to be less probable.

Conclusions

Olive-tree leaves polyphenols modulate AMPK activity, which may become a therapeutic aid in the management of obesity-associated disturbances. The natural occurrence of these compounds may have important nutritional implications for the design of functional ingredients.

Phenolic Components and Antioxidant Activity of Wood Extracts from 10 Main Spanish Olive Cultivars

The chemical composition and radical-scavenging activity of wood samples from 10 main Spanish olive cultivars were studied. The wood samples were collected during the pruning works from trees growing under the same agronomical and environmental conditions. The 10 ethyl acetate extracts were submitted to HPLC-DAD/ESI-MS analysis to determine the phenolic constituents. Seventeen compounds were identified (10 secoiridoids, 3 lignans, 2 phenol alcohols, 1 iridoid, and 1 flavonoid) by comparison with authentic samples. Significant quantitative and qualitative differences were found among olive cultivars. The lignan (+)-1-hydroxypinoresinol 1-O-β-d-glucopyranoside was the major compound in all olive cultivars, except in cultivars 'Farga' and 'Picual'. The multivariate analysis of all data revealed three sets of cultivars with similar compositions. Cultivars 'Gordal sevillana' and 'Picual' had the most distinct chemical profiles. With regard to the radical-scavenging activity, cultivar 'Picual', with oleuropein as the major phenolic, showed the highest activity (91.4 versus 18.6-32.7%).

Traditional Uses, Phytochemistry, and Pharmacology of Olea europaea (Olive)

Aim of the Review. To grasp the fragmented information available on the botany, traditional uses, phytochemistry, pharmacology, and toxicology of Olea europaea to explore its therapeutic potential and future research opportunities. Material and Methods. All the available information on O. europaea was collected via electronic search (using Pubmed, Scirus, Google Scholar, and Web of Science) and a library search. Results. Ethnomedical uses of O. europaea are recorded throughout the world where it has been used to treat various ailments. Phytochemical research had led to the isolation of flavonoids, secoiridoids, iridoids, flavanones, biophenols, triterpenes, benzoic acid derivatives, isochromans, and other classes of secondary metabolites from O. europaea. The plant materials and isolated components have shown a wide spectrum of in vitro and in vivo pharmacological activities like antidiabetic, anticonvulsant, antioxidant, anti-inflammatory, immunomodulatory, analgesic, antimicrobial, antiviral, antihypertensive, anticancer, antihyperglycemic, antinociceptive, gastroprotective, and wound healing activities. Conclusions. O. europaea emerged as a good source of traditional medicine for the treatment of various ailments. The outcomes of phytochemical and pharmacological studies reported in this review will further expand its existing therapeutic potential and provide a convincing support to its future clinical use in modern medicine.

Biorefinery based on olive biomass. State of the art and future trends

With currently more than nine million hectares, olive tree cultivation has spread worldwide, table olives and olive oil as the main products. Moreover, a number of by-products and residues derived from both tree cultivation and the process of industrial olive oil production, most having no practical applications, are obtained yearly. This paper reviews the research regarding these by-products, namely biomass from olive tree pruning, olive stones, olive pomace and wastewaters obtained from the process of olive oil production. Furthermore, a wide range of compounds has been identified and can be produced using a broad definition of the term biorefinery based on olive tree biomass. As an example, this paper reviews ethanol production as one of the main proposed applications, as well as research on other value-added products. Finally, this paper also assesses recent technological advances, future perspectives and challenges in each stage of the process.

Comparative studies for screening of bioactive constituents from various parts of Incarvillea emodi

A comparative study was performed on various parts (shoots, roots and flowers) of Incarvillea emodi. The alcoholic extracts of different parts were fractionated with solvents of different polarity and studied for the determination of total polyphenol content and total antioxidant potential. Furthermore, we have isolated major iridoid glucosides from the dried flowers of I. emodi followed by the comparative cytotoxicity studies of these iridoids against five different human cancer cell lines. The results have demonstrated that ethyl acetate fraction of all parts have higher phenolic content (167.87-294.31 mg/g as gallic acid equivalent) and higher total antioxidant potential (252.95-384.64 mg/g as trolox equivalent). The results of in vitro cytotoxicity studies have indicated that boschnaloside (2) possesses promising anticancer potential against three human cancer cell lines, THP-1, A-549 and PC-3, which belong to leukaemia, lung and prostate cancers, respectively, while plantarenaloside (1) expressed relevant cytotoxic activity against THP-1 cell lines of leukaemia.

Radical-scavenging compounds from olive tree (Olea europaea L.) wood

The purpose of this study was to complete knowledge on the chemical composition and radical-scavenging activity of olive tree wood. Two new monoterpene glycosides, (-)-oleuropeic acid 6'-O-α-D-glucopyranosyl ester (6a) and (-)-perillic acid 1'-O-β-D-primeverosyl ester (8), together with the known compounds (-)-oleuropeic acid (1), (-)-olivil (2), the aldehydic form of oleuropein aglycone (3), (+)-1-hydroxypinoresinol 1-O-β-D-glucopyranoside (4), (-)-oleuropeic acid 1'-O-β-D-glucopyranosyl ester (5), (-)-oleuropeic acid 6'-O-β-D-glucopyranosyl ester (6b), and (-)-olivil 4-O-β-D-glucopyranoside (7) were isolated from an ethyl acetate extract. The radical scavengers found (2-4 and 7) were detected and isolated with the help of the online HPLC-DAD-DPPH/ABTS technique. Compounds 2-4 and 7 displayed a higher antioxidative effect against the free radical DPPH than the reference BHT and lower than hydroxytyrosol, whereas compounds 1, 5, 6a, 6b, and 8 showed no activity.

Effect of Extraction Conditions on the Antioxidant Activity of Olive Wood Extracts

An investigation to optimize the extraction yield and the radical scavenging activity from the agricultural by-product olive tree wood (Olea europaea L., cultivar Picual) using six different extraction protocols was carried out. Four olive wood samples from different geographical origin, and harvesting time have been used for comparison purposes. Among the fifty olive wood extracts obtained in this study, the most active ones were those prepared with ethyl acetate, either through direct extraction or by successive liquid-liquid partitioning procedures, the main components being the secoiridoids oleuropein and ligustroside. An acid hydrolysis pretreatment of olive wood samples before extractions did not improve the results. In the course of this study, two compounds were isolated from the ethanolic extracts of olive wood collected during the olives' harvesting season and identified as (7''R)-7''-ethoxyoleuropein (1) and (7''S)-7''-ethoxyoleuropein (2).

On-line activity screening for radical scavengers from Baccharis chilco

Baccharis plants have been used since ancient times in American traditional medicine. Baccharis chilco is a perennial shrub of temperate regions of South America that grows well in rainfall forests of Colombia. Neither chemical composition nor biological studies of this plant have ever been reported. Two caffeoylquinic acid (CQA) derivatives, 5-O-[(E)-caffeoyl]quinic acid (1) and 3,5-di-O-[(E)-caffeoyl]quinic acid (3), and rosmarinic acid (2) have been isolated from B. chilco growing wild in Colombia, using the on-line HPLC-DAD-DPPH radical-scavenging detection technique as guidance. In the course of the purification work, L-chiro-inositol (4) was also isolated. Structures of the four isolated compounds were determined by spectroscopic methods. Antioxidants 2 and 3 exhibited high antiradical activities evaluated by the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH(.)) assay, although somewhat lower than that of the reference compound ascorbic acid. The on-line HPLC-DAD-DPPH technique allowed a rapid pinpointing of antioxidants in the studied EtOH extract, and the facile guided isolation of the target molecules.

Valuable nutrients and functional bioactives in different parts of olive (Olea europaea L.)-a review

The Olive tree (Olea europaea L.), a native of the Mediterranean basin and parts of Asia, is now widely cultivated in many other parts of the world for production of olive oil and table olives. Olive is a rich source of valuable nutrients and bioactives of medicinal and therapeutic interest. Olive fruit contains appreciable concentration, 1-3% of fresh pulp weight, of hydrophilic (phenolic acids, phenolic alchohols, flavonoids and secoiridoids) and lipophilic (cresols) phenolic compounds that are known to possess multiple biological activities such as antioxidant, anticarcinogenic, antiinflammatory, antimicrobial, antihypertensive, antidyslipidemic, cardiotonic, laxative, and antiplatelet. Other important compounds present in olive fruit are pectin, organic acids, and pigments. Virgin olive oil (VOO), extracted mechanically from the fruit, is also very popular for its nutritive and health-promoting potential, especially against cardiovascular disorders due to the presence of high levels of monounsaturates and other valuable minor components such as phenolics, phytosterols, tocopherols, carotenoids, chlorophyll and squalene. The cultivar, area of production, harvest time, and the processing techniques employed are some of the factors shown to influence the composition of olive fruit and olive oil. This review focuses comprehensively on the nutrients and high-value bioactives profile as well as medicinal and functional aspects of different parts of olives and its byproducts. Various factors affecting the composition of this food commodity of medicinal value are also discussed.

Effect of water extraction on sugars recovery from steam exploded olive tree pruning

Biomass of olive tree pruning can be considered a suitable raw material for the production of ethanol due to its high content of potentially fermentable carbohydrates. However its high extractives content could cause condensation reactions between extractives and acid insoluble lignin during pretreatment, hindering the enzymatic hydrolysis of pretreated material. In this work, the effect of extractives removal before steam explosion of olive tree pruning was evaluated. The objectives are to recover as much glucose as possible in the extraction stage and to avoid the condensation reactions. The effect of temperature and time of water extracted material on sugars recovery was studied using a response surface method according to a central composite design. Extractive removal previous to steam explosion resulted in 20% more total sugars recovery in comparison to a material without water extraction stage.