Phytosterols in banana (Musa spp.) flower inhibit α‐glucosidase and α‐amylase hydrolysations and glycation reaction

Three phytosterols were isolated from Musa spp. flowers for evaluating their capabilities in inhibiting glucosidase and amylase activities and glycation of protein and sugar. The three phytosterols were identified as β‐sitosterol (PS1), 31‐norcyclolaudenone (PS2) and (24R)‐4α, 14α, 4‐trimethyl‐5α‐cholesta‐8, 25(27)‐dien‐3β‐ol (PS3). IC₅₀ values (the concentration of inhibiting 50% of enzyme activity) of PS1, PS2 and PS3 against α‐glucosidase were 283.67, 11.33 and 43.10 μg mL^?1, respectively. For inhibition of α‐amylase, the IC₅₀ values of PS1, PS2 and PS3 were 52.55, 76.25 and 532.02 μg mL^?1, respectively. PS1 was an uncompetitive inhibitor against α‐amylase with K_m at 5.51 μg mL^?1, while PS2 and PS3 exhibited a mixed‐type inhibition with K_m at 52.36 and 2.49 μg mL^?1, respectively. PS1 and PS2 also significantly inhibited the formation of advanced glycation end products (AGEs) in a BSA–fructose model. The results suggest that banana flower could possess the capability in prevention of the diseases associated with abnormal blood sugar and AGEs levels, such as diabetes.     

Inhibitory potential of phenylpropanoid glycosides from Ligustrum purpurascens Kudingcha against α‐glucosidase and α‐amylase in vitro

The leaves of Ligustrum purpurascens are used in a Chinese traditional tea called small‐leaved kudingcha, which is rich in phenylpropanoid glycosides (PPGs) and has many beneficial properties. Two critical exoacting glycoside hydrolase enzymes (glucosidases) involved in carbohydrate digestion are α‐glucosidase and α‐amylase. We investigated the properties of PPGs from L. purpurascens for inhibiting α‐amylase and α‐glucosidase activity in vitro and found IC₅₀ values of 1.02 and 0.73 mg mL^?1, respectively. The patterns of inhibiting both α‐amylase and α‐glucosidase were mixed‐inhibition type. Multispectroscopy and molecular docking studies indicated that the interaction between PPGs and α‐amylase and α‐glucosidase altered the conformation of enzymes, with binding at the site close to the active site of enzymes resulting in changed enzyme activity. Our studies may help in the further health use of small‐leaved kudingcha.     

Screening grape seeds recovered from winemaking by‐products as sources of reducing agents and mammalian α‐glucosidase and α‐amylase inhibitors

Grape seeds collected from vinification of various grape varieties were extracted by supercritical CO₂ for oil recovery. The defatted residues thus obtained were considered as a re‐utilisable co‐product and assessed for phenolic content, reducing capacity and inhibitory activities against mammalian α‐amylase and α‐glucosidase enzymes. Supercritical CO₂ treatment led to higher recovery of anthocyanins. Reducing capacity of phenolic extracts reached up to ~2200 mmolFe(II) kg^?1, much higher than that of various natural phenolic sources. The anthocyanin‐rich extracts showed the highest inhibitory effectiveness towards α‐glucosidase (I₅₀ value equal to ~40 μg gallic acid equivalents (GAE)/mL ~ half than acarbose). Inhibitory effectiveness towards α‐amylase activity was similar among grape varieties, with I₅₀ values comparable to that of acarbose and correlated with proanthocyanidin contents. These results could pave the way for an efficient processing of grapes, including cascade processes, namely: winemaking, oil extraction from recovered grape seeds and phenolic extraction from defatted grape seeds as potential cost‐effective nutraceuticals.     

Anti‐acetylcholinesterase,antidiabetic, anti‐inflammatory,antityrosinase and antixanthine oxidase activities of Moroccan propolis

Biological properties of Moroccan propolis have been scarcely studied. In the present work, the total phenols and flavonoids from 21 samples of propolis collected in different places of Morocco or 3 supplied in the market were determined, as well as the in vitro capacity for inhibiting the activities of acetylcholinesterase, α‐glucosidase, α‐amylase, lipoxygenase, tyrosinase, xanthine oxidase and hyaluronidase. The results showed that samples 1 (region Fez‐Boulemane, Sefrou city) (IC₅₀ = 0.065, 0.006, 0.020, 0.050, 0.014 mg mL^?1) and 23 (marketed) (IC₅₀ = 0.018, 0.002, 0.046, 0.037, 0.008 mg mL^?1) had the best in vitro capacity for inhibiting the α‐amylase, α‐glucosidase, lipoxygenase, tyrosinase and xanthine oxidase activities, respectively. A negative correlation between IC₅₀ values and concentration of phenols, flavones and flavanones was found. These activities corresponded to the generally higher amounts of phenols and flavonoids. In the same region, propolis samples have dissimilar phenol content and enzyme inhibitory activities.     

Changes of porcine pancreas α‐amylase in activity and secondary conformations under inhibition of tea polyphenols

To investigate two‐sided functions of tea polyphenols (TP) in antinutrition and energy balance modulation, TP were extracted from Chinese green tea and used to complex porcine pancreas α‐amylase (PPA). Changes of PPA in activity and secondary conformations were analysed. Porcine pancreas α‐amylase was found sensitive to TP treatment. Tea polyphenols exhibited IC₅₀ at 0.41 mg mL^?1 against PPA and maximum inhibitory rate (98.17%) at 3.0 mg mL^?1. Tea polyphenols inhibition was concluded as noncompetitive pattern based on its unchanged Km value (0.98 mg mL^?1) for soluble starch substrate. Tea polyphenols inhibition arose from pH 1.5 to 10.14, covering gastric and intestinal environments inside body. Circular dichroism spectra analysis revealed regular changes of PPA in secondary conformations (increased proportions of α‐helix and β‐sheet) prior to its inactivation at low TP concentrations. Tea polyphenols‐inhibited PPA had distinct double‐negative peaks at 204 nm and 208 nm. Porcine pancreas α‐amylase was inactivated by TP in ways of complexation and modification of secondary conformations.     

α‐Glucosidase and α‐amylase inhibitory activities of phloroglucinal derivatives from edible marine brown alga,Ecklonia cava

BACKGROUND: Diabetes mellitus (DM) is a chronic metabolic disorder characterized by defects in insulin secretion and action, which can lead to damaged blood vessels and nerves. With respect to effective therapeutic approaches to treatment of DM, much effort has being made to investigate potential inhibitors against α‐glucosidase and α‐amylase from natural products. The edible marine brown alga Ecklonia cava has been reported to possess various interesting bioactivities, which are studied here. RESULTS: In this study, five phloroglucinal derivatives were isolated from Ecklonia cava: fucodiphloroethol G ( 1 ), dieckol ( 2 ), 6,6′‐bieckol ( 3 ), 7‐phloroeckol ( 4 ) and phlorofucofuroeckol A ( 5 ); compounds 1, 3 and 4 were obtained from this genus for the first time and with higher yield. The structural elucidation of these derivatives was completely assigned by comprehensive analysis of nuclear magnetic spectral data. The anti‐diabetic activities of these derivatives were also assessed using an enzymatic inhibitory assay against rat intestinal α‐glucosidase and porcine pancreatic α‐amylase. Most of these phlorotannins showed significant inhibitory activities in a dose‐dependent manner, responding to both enzymes, especially compound 2 , with the lowest IC₅₀ values at 10.8 µmol L^?1 (α‐glucosidase) and 124.9 µmol L^?1 (α‐amylase), respectively. Further study of compound 2 revealed a non‐competitive inhibitory activity against α‐glucosidase using Lineweaver‐Burk plots. CONCLUSION: These results suggested that Ecklonia cava can be used for nutritious, nutraceutical and functional foods in diabetes as well as for related symptoms. Copyright © 2009 Society of Chemical Industry     

Tannin fraction from Ampelopsis grossedentata leaves tea (Tengcha) as an antioxidant and α‐glucosidase inhibitory nutraceutical

Leaf of Ampelopsis grossedentata is a new resource of functional foods with healthful properties. Antioxidant and α‐glucosidase inhibitory activities of water extract (made in the style of drinking), tannin fraction (TF) and dihydromyricetin (DMY) from A. grossedentata leaves were evaluated. The main component of TF was identified as gallotannins. DPPH and ABTS radical scavenging activities and reducing power of TF were superior to those of water extract, however, inferior to those of DMY. In no PBS wash protocol of cellular antioxidant activity assay, DMY and TF exhibited similarly, while in PBS wash protocol, the value of TF was higher than that of DMY. In addition, TF possessed the highest α‐glucosidase inhibitory activities (IC₅₀ = 1.94 μg mL^?1), followed by water extract (IC₅₀ = 23.10 μg mL^?1) and DMY (IC₅₀ = 72.21 μg mL^?1). The strong α‐glucosidase inhibitory activity of TF may attribute to the binding capacity to enzymes, as confirmed by fluorescence analysis.     

Interaction of aqueous extracts of two varieties of Yam tubers (Dioscorea spp) on some key enzymes linked to type 2 Diabetes in vitro

This study sought to assess the effect of processing of yam flour [from white yam (Dioscorea rotundata) and water yam (Dioscorea alata)] to paste, on the antioxidant properties and inhibition of key enzymes linked to type‐2 diabetes (α‐amylase and α‐glucosidase). The phenolic content (phenol and flavonoid), antioxidant properties, α‐amylase and α‐glucosidase inhibitory properties of the aqueous extracts of the yam products were determined. Processing into paste caused significant (P < 0.05) percentage decrease in their total phenol and flavonoid content of the yam varieties. However, significant increase (P < 0.05) in the antioxidant properties of the yam varieties was observed after processing. Furthermore, the yam extracts inhibited α‐amylase and α‐glucosidase activities in vitro in a dose‐dependent parttern (1–4 mg mL^?1), however, the pasting process caused significant (P < 0.05) decrease in the α‐amylase inhibitory and α‐glucosidase inhibitory activities. Therefore, processing the yam varieties into paste (browned) could potentially increase their antioxidant capacity as well as decreasing their α‐amylase and α‐glucosidase inhibitory properties.     

Inhibitory activity towards human α‐amylase in wheat flour and gluten

Wheat α‐amylase inhibitors (AI) have been targeted as potential triggers of noncoeliac gluten or wheat sensitivity (NCGS). The aim of this study was to determine AI activity towards α‐amylase from human source in wheat cultivars. Contrary to barley, buckwheat, or oats, high level of AI activity was found in wheat and, to a lesser extent, rye. AI activity (mean IC₅₀ = 137 μg mL^?1) did not vary with respect to ancient or recently developed wheat cultivars. Vital wheat gluten had very high and heat‐stable AI activity (mean IC₅₀ = 23 μg mL^?1), higher than wheat starch (?10 000 μg mL^?1) or acarbose (40 μg mL^?1), a medication for the management of hyperglycaemia and potentially causing digestive disorders due to the accumulation of undigested carbohydrates in the intestine. Data suggest that eating raw wheat gluten, flour or dough could pose a health risk.     

Identification of α‐glucosidase inhibitors from a new fermented tea obtained by tea‐rolling processing of loquat (Eriobotrya japonica) and green tea leaves

BACKGROUND: A new fermented tea produced by tea‐rolling processing of loquat (Eriobotrya japonica) leaf with green tea leaf (denoted as LG tea) showed a potent antihyperglycaemic effect in maltose‐loaded rats. The aim of this study, therefore, was to identify α‐glucosidase inhibitors in the antihyperglycaemic tea product. RESULTS: LG tea had a threefold higher maltase‐inhibitory activity (IC₅₀ 0.065 mg dried extract mL^?1) than either the constituent loquat leaf or green tea alone. In addition, LG tea favourably inhibited maltase action rather than sucrase action. As a result of bio‐guided high‐performance liquid chromatography separations of LG tea, theasinensin A, theasinensin B, strictinin and 1,6‐digalloylglucose were newly identified as maltase inhibitors with IC₅₀ values of 142, 225, 398 and 337 µmol L^?1 respectively, along with previously identified catechins and theaflavins. CONCLUSION: Judging from the magnitude of the α‐glucosidase‐inhibitory contribution of each isolated compound to the overall inhibition of LG tea, catechins were the main candidates responsible for α‐glucosidase or maltase inhibition in LG tea, followed by theaflavins, theasinensins, strictinin and 1,6‐digalloylglucose. Copyright © 2010 Society of Chemical Industry     

Validation of analytical method for α‐dicarbonyl compounds using gas chromatography–nitrogen phosphorous detector and their levels in alcoholic beverages

This study aimed to establish an analytical method for α‐dicarbonyl compounds (α‐DCs) including glyoxal, methylglyoxal and diacetyl, to determine the content of α‐DCs in 101 various alcoholic beverages using gas chromatography–nitrogen phosphorous detector (GC‐NPD) and to perform exposure assessment. The limit of detection and limit of quantification for α‐DCs were 0.05–0.22 and 0.15–0.70 μg g^?1, respectively. The accuracy and precision were validated in five matrices. The raspberry fruit wine had the highest value at 139.74 μg g^?1 total α‐DCs. The lowest α‐DC concentration among the beverages was detected in rice wine (Makgeolli) at 1.59 μg g^?1. The levels of α‐DCs in various samples were detected as follows: 1.59–56.68 μg g^?1 in rice wine (Makgeolli), 2.73–16.77 μg g^?1 in beer, 8.22–139.74 μg g^?1 in fruit wine and 8.17–91.56 μg g^?1 in rice wine (Cheongju). The estimated daily intake of α‐DCs in the intake‐only group and population group was calculated as 4.22–97.94 μg kg^?1 bw day^?1 and 0.28–7.13 μg kg^?1 bw day^?1, respectively.     

Inhibitory activities of kaempferol,galangin, carnosic acid and polydatin against glycation and α‐amylase and α‐glucosidase enzymes

The activities of four natural phenolics, kaempferol, galangin, carnosic acid and polydatin in scavenging free radicals, inhibiting advanced glycation end‐product (AGE) formation, α‐amylase and α‐glucosidase and trapping methylglyoxal (MGO), were evaluated in this study. Carnosic acid and galangin had the highest activity in scavenging free radicals. Kaempferol and galangin had the greatest activity in preventing bovine serum albumin (BSA) against glycation and reducing glycated proteins. Polydatin had the greatest performance in trapping MGO to reduce glycation reaction. However, there was no significant difference for kaempferol, galangin and carnosic acid in inhibiting AGE formation by BSA‐MGO reaction. Kaempferol, galangin and carnosic acid were the competitive inhibitors for α‐amylase, while kaempferol and carnosic acid were noncompetitive inhibitors for α‐glucosidase. However, polydatin showed as a mixed noncompetitive inhibitor for both α‐amylase and α‐glucosidase. The results indicated that the four natural phenolics have potential in inhibiting AGE production and the digestive enzymatic activity with different mechanisms.     

Screening culinary herbs for antioxidant and α‐glucosidase inhibitory activities

Twelve commonly consumed culinary herbs were assessed for their potential effect in mitigating oxidative stress and postprandial hyperglycaemia: River Mint, Vietnamese Mint, Fish Mint, Spearmint, Sweet Basil, Thai Basil, Coriander, Lemon Verbena, Vietnamese Perilla, Rice Patty, Sawtooth and Rosemary. The radical scavenging and reducing antioxidant activity of the herbs were quite variable ranging from 31–652 mg Trolox Equivalent to 35–512 mg Ferrous Equivalent per gram dried leaves, respectively. The herbs were largely inactive against pancreatic α‐amylase, but showed strong inhibitions against yeast α‐glucosidase at 100 μg Gallic Acid Equivalent (GAE) per millilitre. Vietnamese Mint is the most potent herbs with the concentration required for 50% inhibition of activity of 6.9 μg Dried Leaves per millilitre. In addition, Vietnamese Mint was the only herb that produced significant inhibition of rat intestinal α‐glucosidases, reducing activity to 29.6% at 100 μg GAE mL^?1 compared with control.     

α-Glucosidase- and α-amylase-inhibitory activities of phlorotannins from Eisenia bicyclis

BACKGROUND: In an effort to develop alternative therapeutic agents, strong inhibitory activity against α‐glucosidase and α‐amylase was detected in Eisenia bicyclis methanolic extract. RESULTS: In this study, two phlorotannins were isolated from E. bicyclis and characterised by chromatography and nuclear magnetic resonance. The active substances were identified as fucofuroeckol A (FF) and dioxinodehydroeckol (DD). To the authors' knowledge, this is the first report of the identification of these substances in E. bicyclis. However, to date, no antidiabetic activity of FF and DD has been reported. Both phlorotannins demonstrated significant inhibitory activity against α‐glucosidase and α‐amylase. FF showed potent antidiabetic activity, with IC₅₀ values of 131.34 nmol L^?1 against α‐glucosidase and 42.91 µmol L^?1 against α‐amylase. The corresponding IC₅₀ values of DD were 93.33 nmol L^?1 and 472.7 µmol L^?1. Furthermore, kinetic analysis revealed that FF and DD exhibited non‐competitive inhibitory activity against α‐glucosidase. CONCLUSION: These results suggest that FF and DD may be candidates for the development of an antidiabetic pharmaceutical agent or food additive. Copyright © 2012 Society of Chemical Industry     

Impact of α‐amylase and maltodextrin on physicochemical,functional and antioxidant capacity of spray‐dried purple sweet potato flour

BACKGROUND: Purple sweet potato flour could be used to enhance food products through colour, flavour and nutrients. Purple sweet potato flour has not yet been prepared with maltodextrin and amylase treatment using spray drying. Thus, the investigation was to evaluate the effect of various levels of maltodextrin (30 and 50 g kg^?1 w/v), amylase (3 and 7 g kg^?1 puree) and combined with maltodextrin and amylase on the physicochemical, functional and antioxidant capacity of spray dried purple sweet potato flours. RESULTS: Amylase and amylase with maltodextrin‐treated flours had a higher anthocyanin and total phenolic content than the control and maltodextrin‐treated flours. However, the antioxidant capacity was higher in the control and maltodextrin‐treated flours compared to the amylase and amylase with maltodextrin‐treated flours. The control had a higher water absorption index and lower water solubility index compared to the maltodextrin and combined with amylase and maltodextrin‐treated flours. On the other hand, maltodextrin increased whereas α‐amylase decreased the glass transition temperature. With respect to morphology, the particles of amylase‐treated flours were smaller than the control and maltodextrin‐treated flours. CONCLUSION: The results showed that good quality flour could be prepared by combining 30 g kg^?1 maltodextrin and 7 g kg^?1 amylase treatment. Copyright © 2009 Society of Chemical Industry     

Starch but not protein digestibility is altered in pigs fed transgenic peas containing α‐amylase inhibitor

Eighteen individually housed boars were randomly allocated to one of three dietary treatments, an experimental wheat diet containing 989.4 g kg^?1 of a basal wheat diet, or this experimental wheat diet with 500 g kg^?1 of the basal wheat diet replaced with 500 g kg^?1 of either transgenic or non‐transgenic peas. The transgenic peas expressed the bean (Phaseolus vulgaris L.) α‐amylase inhibitor 1 gene. Diets contained n‐hexatriacontane (0.2 g kg^?1) as an indigestible marker to allow the determination of nutrient digestibility at the terminal ileum. Pigs were offered 1.6 kg day^?1 for 15 days, after which they were anaesthetised, the ileal and faecal digesta collected and the pigs subsequently euthanased. The ileal dry matter and starch digestibilities of the experimental wheat, non‐transgenic and transgenic pea diets were 78.3, 74.2 and 45.8% and 95.9, 95.2 and 42.4%, respectively. The apparent nutrient digestibilities of the non‐transgenic and transgenic peas were determined by difference. The ileal dry matter digestibility was significantly reduced in the transgenic peas compared with the non‐transgenic peas (12.7 and 69.9%, respectively; P = 0.006), which was largely due to a reduced starch digestibility. The apparent crude protein digestibilities of the transgenic peas were similar to the non‐transgenic, being 79.7 and 78.5%, respectively. The amino acid digestibilities of the transgenic and non‐transgenic peas were also similar. Copyright © 2006 Society of Chemical Industry     

Characterization of an α‐amylase from sorghum (Sorghum bicolor) obtained under optimized conditions

Sorghum malt α‐amylase can compete with bacterial α‐amylase in industrial applications, if sufficiently stable and produced in a large enough quantity. Conditions for maximal α‐amylase production in sorghum malt and the physico‐chemical properties of the α‐amylase so produced are reported in this study. Sorghum grains were steeped in buffers with varying pH (4.0–8.0) for 24 h, at room temperature, and germinated for another 48 h to obtain the green malt. The buffer that induced the highest quantity of α‐amylase was chosen as the optimal pH and served as the medium for further steeping experiments conducted at different temperatures (10, 20, 30, 40, 50 and 60°C). The α‐amylase activity in the extract was determined in order to obtain the optimum temperature for α‐amylase induction at this particular pH. For the purpose of comparison, the α‐amylase produced at the optimum pH and temperature was purified to apparent homogeneity by a combination of ion‐exchange and size‐exclusion chromatography, and further characterized. Eight‐fold higher α‐amylase activity was induced in pH 6.5 buffer at 20°C compared with water, the traditional steeping medium. The K_m and V_max were estimated to be 1.092 ± 0.05 mg mL^?1 and 3516 ± 1.981 units min^?1, respectively. The activation energy of the purified amylase for starch hydrolysis was 6.2 kcal K^?1 mol^?1. Chlorides of calcium and manganese served as good activators, whereas CuSO₄ inhibited the enzyme with a 42% loss in activity at 312 mm salt concentration. Copyright © 2012 The Institute of Brewing & Distilling     

Acceptability,storage stability and costing of α‐amylase‐treated maize–beans–groundnuts–bambaranuts complementary blend

The effects of α‐amylase treatment on physical properties, acceptability to mothers, and cost of roasted and extruded maize–beans–groundnuts–bambaranuts complementary porridge recipes were assessed prior to their industrial production. Storage stability of the extruded α‐amylase‐treated fortified blend was assessed at 2 weeks and 6 months by sensory evaluation, peroxide value, water activity and microbiological load. The use of α‐amylase at 0.04% w/w enhanced porridge acceptability and resulted in 88% and 122% increase in flour concentration for roasted and extrusion‐cooked porridge flour, respectively, while maintaining porridge viscosity at 1000‐fold lower than that of traditionally used porridges. The extrusion cooked blend was stable for 6 months. α‐Amylase application increased the unit cost of the developed blend by only 1.4%. The total cost was less than US $ 2 kg^?1, half the minimum price of commercially available complementary foods. Further work on marketing and the efficacy of this inexpensive food on growth of infants is warranted. Copyright © 2007 Society of Chemical Industry     

α‐Amylase inhibitors from an Indonesian medicinal herb,Phyllanthus urinaria

BACKGROUND: Diabetes mellitus and associated diseases are an increasing problem around the world. One of the hyperglycemic remedies is glucose absorption reduction by suppressing carbohydrate digestion due to utilization of α‐amylase inhibitors. RESULTS: Prospective herbs were analyzed by in vitro enzyme assay to evaluate their inhibitory activity against porcine pancreatic amylase (PPA), and it was found that Phyllanthus urinaria and three other herbs to showed a potent inhibitory activity. A 50% aqueous methanol‐soluble extract of the leaves of P. urinaria was chromatographed using a silica gel column. The active fractions were further purified by preparative high‐performance liquid chromatography to isolate active principles against PPA. Structural determination revealed that these isolated compounds were gallic acid, corilagin, and macatannin B, and showed mild activity against PPA (activity in 1 mmol L^?1 concentration: 23%, 21%, 33%, respectively). CONCLUSION: P. urinaria extracts show inhibitory activity against PPA. This activity, together with the information on isolated compounds, may benefit further exploration of P. urinaria utilization in the management of borderline diabetes patients. Copyright © 2011 Society of Chemical Industry     

Chemical composition,antioxidant activity and anti‐lipase activity of Origanum vulgare and Lippia turbinata essential oils

This study reported the chemical composition, phenolic content, antioxidant and anti‐lipase activity of oregano and Lippia essential oils. The major compounds found in oregano essential oil were γ‐terpinene (32.10%), α‐terpinene (15.10%), p‐cymene (8.00%) and thymol (8.00%). In Lippia essential oil, α‐limonene (76.80%) and 1,8‐cineole (4.95%) represented the major compounds. Oregano essential oil had higher phenolic content (12.47 mg gallic acid mL^?1) and DPPH scavenging activity (IC₅₀ 0.357 μg mL^?1) than Lippia essential oil (7.94 mg gallic acid mL^?1 and IC₅₀ 0.400 μg mL^?1, respectively). Both essential oils had similar antioxidant indexes (about 1.2) determined by Rancimat. Moreover, oregano essential oil had also higher anti‐lipase activity (IC₅₀ 5.09 and 7.26 μg mL^?1). Higher phenolic content in the essential oils was related with higher scavenging and anti‐lipase activities. Oregano and Lippia essential oils could be used as natural antioxidants on food products.