Studies on antioxidants: their carcinogenic and modifying effects on chemical carcinogenesis

Phytochemical Analysis and Evaluation of Antioxidant and Antimicrobial Properties of Essential Oils and Seed Extracts of Anethum graveolens from Southern Morocco: In Vitro and In Silico Approach for a Natural Alternative to Synthetic Preservatives

Anethum graveolens is an aromatic plant traditionally used as an antispasmodic and carminative. The objective of this study is to analyze the chemical composition of the essential oils and extracts obtained from seeds gathered in Errachidia, southern Morocco. Additionally, the antioxidant and antimicrobial properties of these oils and extracts will be evaluated. GC-MS analysis of the EO isolated by hydrodistillation revealed that its main compounds were E-anethole (38.13%), estragole (29.32%), fenchone (17.21%), and α-pinene (7.37%). The phenolic components were extracted using the methods of decoction and Soxhlet. The assay of the phenolic compounds showed that A. graveolens seeds contained considerable amounts of polyphenols, flavonoids, and condensed tannins, with variable levels depending on the extract analyzed. HPLC/UV-ESI-MS analyses performed on the decoction revealed a structural diversity of the molecules present in this extract, the most important of which were umbelliferone (12.35%), 3-hydroxyflavone (11.23%), rosmanol (8.95%), biotin (8.36%), emmotin H (4.91%), and coumarin (4.21%). The antioxidant activity, as determined by three techniques (DPPH•, FRAP, and CAT), demonstrated that the essential oils (EOs) and extracts had a potent capacity to counteract detrimental free radicals, control the generation of reactive oxygen species, and mitigate oxidative damages. The antimicrobial activity of the Eos and extracts was carried out in a liquid medium against five strains (E. cloacae, K. pneumoniae, E. coli, S. aureus, and S. epidermidis) and four candidiasis (C. albicans, C. dubliniensis, C. tropicalis, and C. parapsilosis) and Aspergillus niger. The results showed the effectiveness of the EOs compared to the aqueous, ethanolic, and decoction extracts against most of the microorganisms tested. In addition, the ethanolic extract showed antifungal activity that was distinguished from that of the other extracts. The antimicrobial efficacy of the essential oils under study can primarily be attributed to the synergistic interactions among its three principal constituents (E-anethole, estragole, and fenchone). Furthermore, molecular docking and molecular dynamics simulation results reveal significant interactions and stability between the selected bioactive compounds and different target proteins involved in antimicrobial and antioxidant activities. Compounds like 3-hydroxyflavone, emmotin H, trans-caftaric acid, methyl rosmarinate, 1-caffeoyl-beta-D-glucose, and kaempferol exhibited better binding energies with the explored proteins, indicating their potential as antimicrobial and antioxidant agents. Finally, our findings emphasize the significance of A. graveolens seeds as a promising reservoir of advantageous health compounds that can serve as organic substitutes for the presently employed synthetic preservatives.

Chemico-pharmacological and computational studies of Ophiorrhiza fasciculata D. Don and Psychotria silhetensis Hook. f. focusing cytotoxic, thrombolytic, anti-inflammatory, antioxidant, and antibacterial properties

The current study sought to examine the pharmacological potentials of crude methanolic extracts of Ophiorrhiza fasciculata and Psychotria silhetensis, as well as their various solvent fractionates, with a focus on cytotoxic, thrombolytic, membrane stabilizing, antioxidant, and antibacterial activities via in vitro and in silico approaches. The extensive chromatographic and spectroscopic analyses confirmed and characterized two compounds as (±)-licarin B (1) and stigmasterol (2) from O. fasciculata and P. silhetensis, respectively. Petroleum ether soluble fraction of O. fasciculata and the aqueous soluble fraction of P. silhetensis showed the lowest 50% lethal concentrations (1.41 and 1.94 μg/mL, respectively) in brine shrimp bioassay. Likewise, petroleum ether soluble fraction of O. fasciculata and aqueous soluble fraction of P. silhetensis showed the highest thrombolytic activity with 46.66% and 50.10% lyses of the clot, respectively. The methanol and dichloromethane soluble fractions of O. fasciculata reduced erythrocyte hemolysis by 64.03% and 37.08%, respectively, under hypotonic and heat-induced conditions, compared to 81.97% and 42.12% for standard acetylsalicylic acid. In antioxidant activity test, aqueous soluble fraction O. fasciculata (IC50 = 7.22 μg/mL) revealed promising antioxidant potentialities in comparison to standard butylated hydroxytoluene (IC50 = 21.20 μg/mL). In antibacterial screening, chloroform, and dichloromethane soluble fractions of P. silhetensis showed a mild antibacterial activity compared with the standard drug ciprofloxacin. Additionally, the molecular docking study corroborated the current in vitro findings, and the isolated two constituents had higher binding affinities toward epidermal growth factor receptor, tissue plasminogen activator, vFLIP-IKK gamma stapled peptide dimer, glutathione reductase, and dihydrofolate reductase enzyme than their corresponding standard drugs. In addition, the both isolated compounds exerted favorable pharmacokinetics (absorption, distribution, metabolism, excretion) and toxicological profiles with drug-like qualities in computational-based ADMET and drug likeliness analyses. The current research suggests that both plants have potential as a natural treatment for treating thrombosis, inflammation, and oxidative stress. However, more thorough research is required to thoroughly screen for phytochemicals and pinpoint the precise mechanisms of action of the bioactive metabolites derived from these plants against a broad range of molecular targets.

Polar microalgae extracts protect human HaCaT keratinocytes from damaging stimuli and ameliorate psoriatic skin inflammation in mice

BACKGROUND

Polar microalgae contain unique compounds that enable them to adapt to extreme environments. As the skin barrier is our first line of defense against external threats, polar microalgae extracts may possess restorative properties for damaged skin, but the potential of microalgae extracts as skin protective agents remains unknown.

PURPOSE

This study aimed to analyze compound profiles from polar microalgae extracts, evaluate their potential as skin epithelial protective agents, and examine the underlying mechanisms.

METHODS

Six different polar microalgae, Micractinium sp. (KSF0015 and KSF0041), Chlamydomonas sp. (KNM0029C, KSF0037, and KSF0134), and Chlorococcum sp. (KSF0003), were collected from the Antarctic or Arctic regions. Compound profiles of polar and non-polar microalgae extracts were analyzed using gas chromatography-mass spectrometry (GC-MS). The protective activities of polar microalgae extracts on human keratinocyte cell lines against oxidative stress, radiation, and psoriatic cytokine exposure were assessed. The potential anti-inflammatory mechanisms mediated by KSF0041, a polar microalga with protective properties against oxidative stress, ultraviolet (UV) B, and an inflammatory cytokine cocktail, were investigated using RNA-sequencing analysis. To evaluate the therapeutic activity of KSF0041, an imiquimod-induced murine model of psoriatic dermatitis was used.

RESULTS

Polar microalgae contain components comparable to those of their non-polar counterparts, but also showed distinct differences, particularly in fatty acid composition. Polar microalgae extracts had a greater ability to scavenge free radicals than did non-polar microalgae and enhanced the viability of HaCaT cells, a human keratinocyte cell line, following exposure to UVB radiation or psoriatic cytokines. These extracts also reduced barrier integrity damage and decreased mRNA levels of inflammatory cytokines in psoriatic HaCaT cells. Treatment with KSF0041 extract altered the transcriptome of psoriatic HaCaT cells toward a more normal state. Furthermore, KSF0041 extract had a therapeutic effect in a mouse model of psoriasis.

CONCLUSIONS

Bioactive compounds from polar microalgae extracts could provide novel therapeutics for damaged and/or inflamed skin.

Investigation of antioxidant, anti-ulcer, and analgesic potential of a metal-curcumin complex

The goal of the current study was to investigate the antioxidant, anti-ulcer, and analgesic properties of a metal-curcumin complex (MCC) utilizing different mouse and rat models. The antioxidant component of the analysis was completed in vitro, whereas the other activities were completed in vivo. The 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical cation scavenging test, the ferric-reducing antioxidant power (FRAP) assay, and the 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH) free radical scavenging assay were used to measure the antioxidant activity. MCC demonstrated potent radical scavenging abilities. In all three experiments, Trolox served as the reference substance. When curcumin's radical scavenging abilities were compared, it became clear that MCC was a superior radical scavenger. Using the ethanol-induced technique on Sprague-Dawley rats, the anti-ulcerogenic effect was assessed. It shows that at an oral dosage of 100 mg/kg body weight, MCC might provide gastroprotection (b.w.). Additionally, we have examined MCC's potential as an analgesic. Swiss albino mice were used to measure the analgesic activity of MCC using the hot plate technique. At an oral dosage of 50 mg/kg b.w., MCC displayed analgesic efficacy. As a result, MCC could be useful in the management of inflammatory diseases.

Chronic Exposure to the Food Additive tBHQ Modulates Expression of Genes Related to SARS-CoV-2 and Influenza Viruses

Background. tert-butylhydroquinone (tBHQ) is an antioxidant commonly used as a food additive. Studies suggest that tBHQ could modulate immune responses to influenza and SARS-CoV-2 infection. In our transcriptomic analysis we explored the molecular mechanisms behind tBHQ’s modulatory properties and the relationships to respiratory viral infections. Methods. tBHQ was administered per os to BALB/c mice (1.5% [w/w]) for 20 days. Splenic T cells were isolated with magnetic separation and subjected to transcriptomic analysis. Gene-set enrichment analysis and g:Profiler was conducted to provide a functional interpretation of significantly changed genes. Further analysis for AHR/NRF2 binding sites was performed with GeneHancer. Results. In CD4⁺ cells, we found significantly altered expression of 269 genes by tBHQ. Of them, many had relevance in influenza infection such as genes responsible for virus entry (Anxa1/2, Cd14), interferon signaling (Dusp10, Tnfsf13), or prostaglandin synthesis (Ptgs1/2). In SARS-CoV-2 infections, interferon signaling (Ifitm1), proteolytic enzymes (CtsB), and also cell-surface proteins (Cd14, Cd151) were among the prominent alterations after tBHQ exposure. Of these genes, many had one or more binding sites for AHR and NRF2, two major xenosensors triggered by tBHQ. Conclusions. Our results strongly suggest that a common food additive, tBHQ, can modulate virus-dependent processes in both influenza and SARS-CoV-2 infections.

A Mini-Review: Effect of Medium on the Activity of Eugenol

Abstract:

The role of essential fatty acids is vital in the life of a human being. The lack of essential fatty acids causes various diseases such as cardiovascular, inflammatory bowel and obesity. Although synthetic antioxidants have already been used, nowadays, the demand for natural antioxidants has increased mainly because of the adverse effects of synthetic antioxidants. Spices are widely used in this context as a source of natural antioxidants. It has been observed that they also act as pro-oxidant. This review aims to evaluate the fundamental reason for the different activities of the spices by studying the example of Eugenol, a principal phenolic constituent of clove oil. The chemistry concerning the mechanism to display antioxidant and pro-oxidant activity is currently being reviewed. The isomerization of Eugenol to Isoeugenol plays a key role in exhibiting dissimilar behaviour of the Eugenol. Under the polar medium, isomerization of Eugenol does not take place and it acts as an antioxidant. However, in the non-polar medium, Eugenol isomerizes to Isoeugenol and displays a pro-oxidant effect. In a basic medium, Eugenol isomerizes to Isoeugenol undergoing degradation. Hence, to utilize the beneficial activity of Eugenol, it should be present in a polar or acidic medium. It can be concluded from this review article that the structural form of any molecule plays a major role in utilizing its activity and is also dependent on the medium. Hence, the medium also performs a vital role to influence the activity of any molecule.

Antioxidant Compounds from Microalgae: A Review

The demand for natural products isolated from microalgae has increased over the last decade and has drawn the attention from the food, cosmetic and nutraceutical industries. Among these natural products, the demand for natural antioxidants as an alternative to synthetic antioxidants has increased. In addition, microalgae combine several advantages for the development of biotechnological applications: high biodiversity, photosynthetic yield, growth, productivity and a metabolic plasticity that can be orientated using culture conditions. Regarding the wide diversity of antioxidant compounds and mode of action combined with the diversity of reactive oxygen species (ROS), this review covers a brief presentation of antioxidant molecules with their role and mode of action, to summarize and evaluate common and recent assays used to assess antioxidant activity of microalgae. The aim is to improve our ability to choose the right assay to assess microalgae antioxidant activity regarding the antioxidant molecules studied.

Benzylidene-6-hydroxy-3,4-dihydronaphthalenone chalconoids as potent tyrosinase inhibitors

Background and purpose:

Tyrosinase enzyme has a key role in melanin biosynthesis by converting tyrosine into dopaquinone. It also participates in the enzymatic browning of vegetables by polyphenol oxidation. Therefore, tyrosinase inhibitors are useful in the fields of medicine, cosmetics, and agriculture. Many tyrosinase inhibitors having drawbacks have been reported to date; so, finding new inhibitors is a great need.

Experimental approach:

A variety of 6-hydroxy-3,4-dihydronaphthalenone chalcone-like analogs (C1-C10) have been synthesized by aldol condensation of 6-hydroxy tetralone and differently substituted benzaldehydes. The compounds were evaluated for their inhibitory effect on mushroom tyrosinase by a spectrophotometric method. Moreover, the inhibition manner of the most active compound was determined by Lineweaver-Burk plots. Docking study was done using AutoDock 4.2. The drug-likeness scores and ADME features of the active derivatives were also predicted.

Results/Findings:

Most of the compounds showed remarkable inhibitory activity against the tyrosinase enzyme. 6-Hydroxy-2-(3,4,5-trimethoxybenzylidene)-3,4-dihydronaphthalen-1(2H)-one (C2) was the most potent derivative amongst the series with an IC₅₀ value of 8.8 μM which was slightly more favorable to that of the reference kojic acid (IC₅₀ = 9.7 μM). Inhibitory kinetic studies revealed that C2 behaves as a competitive inhibitor. According to the docking results, compound C2 formed the most stable enzyme-inhibitor complex, mainly via establishing interactions with the two copper ions in the active site. In silico drug-likeness and pharmacokinetics predictions for the proposed tyrosinase inhibitors revealed that most of the compounds including C2 have proper drug-likeness scores and pharmacokinetic properties.

Conclusion and implications:

Therefore, C2 could be suggested as a promising tyrosinase inhibitor that might be a good lead compound in medicine, cosmetics, and the food industry, and further drug development of this compound might be of great interest.

Effects of lyophilized black mulberry water extract on lipid oxidation, metmyoglobin formation, color stability, microbial quality and sensory properties of beef patties stored under aerobic and vacuum packaging conditions

The objective was to determine the effects of different concentrations of lyophilized black mulberry water extract (BMWE) on lipid oxidation, metmyoglobin (MMb) formation, color stability, microbial quality, and sensory properties of aerobic (AP) and vacuum (VP) packaged beef patties during 15 days of chilled storage. Compared to control, incorporating of BMWE decreased (P < .01) the pH, thiobarbituric acid reactive substances (TBARS), MMb, and hue angle values of both AP and VP beef patties, while improving the redness (a*) and chroma values (P < .01). Addition of BMWE contributed significantly to extending the shelf life of beef patties by limiting lipid oxidation, discoloration and microbial growth during storage compared to control (P < .01). Although the lowest TAMB (total aerobic mesophylic bacteria) counts, TBARS and MMb values were determined in 0.4% BMWE groups, 0.2% BMWE was the most favourable concentration considering sensory acceptability and instrumental redness. These results showed that BMWE could be used as a promising natural colorant, antioxidant and antimicrobial agent in beef patties instead of synthetic additives.

Antioxidant Production in Dunaliella

Microalgae have become an attractive natural source of a diverse range of biomolecules, including enzymatic and non-enzymatic antioxidants; nevertheless, economically sustainable production of such compounds from microalgae biomass is still challenging. The main hurdles are: (a) increasing microalgae yield; (b) achieving optimal cultivation conditions; (c) energy-efficient and cost-effective downstream processing (extraction and purification); (d) optimal storage of post-processed antioxidant molecules. This review provides a detailed overview of enzymatic and non-enzymatic antioxidants in the cellular metabolism of the commercially important microalgae Dunaliella, industrial applications of antioxidant enzymes, strategies to enhanced antioxidant accumulation in cells, and the opportunities and limitations of current technologies for antioxidant enzymes production from microalgae biomass as an alternative to common microbial sources.

Production and properties of non-cytotoxic pyomelanin by laccase and comparison to bacterial and synthetic pigments

Pyomelanin is a polymer of homogentisic acid synthesized by microorganisms. This work aimed to develop a production process and evaluate the quality of the pigment. Three procedures have been elaborated and optimized, (1) an HGA-Mn²⁺ chemical autoxidation (Pyo_CHEM yield 0.317 g/g substrate), (2) an induced bacterial culture of Halomonas titanicae through the 4-hydroxyphenylacetic acid-1-hydroxylase route (Pyo_BACT, 0.55 g/L), and (3) a process using a recombinant laccase extract with the highest level produced (Pyo_ENZ, 1.25 g/g substrate) and all the criteria for a large-scale prototype. The chemical structures had been investigated by ¹³C solid-state NMR (CP-MAS) and FTIR. C_ar-C_ar bindings predominated in the three polymers, C_ar-O-C_ar (ether) linkages being absent, proposing mainly C₃-C₆ (α-bindings) and C₄-C₆ (β-bindings) configurations. This work highlighted a biological decarboxylation by the laccase or bacterial oxidase(s), leading to the partly formation of gentisyl alcohol and gentisaldehyde that are integral parts of the polymer. By comparison, Pyo_ENZ exhibited an M_w of 5,400 Da, was hyperthermostable, non-cytotoxic even after irradiation, scavenged ROS induced by keratinocytes, and had a highly DPPH-antioxidant and Fe³⁺-reducing activity. As a representative pigment of living cells and an available standard, Pyo_ENZ might also be useful for applications in extreme conditions and skin protection.

Crustacean Waste-Derived Chitosan: Antioxidant Properties and Future Perspective

Chitosan is obtained from chitin that in turn is recovered from marine crustacean wastes. The recovery methods and their varying types and the advantages of the recovery methods are briefly discussed. The bioactive properties of chitosan, which emphasize the unequivocal deliverables contained by this biopolymer, have been concisely presented. The variations of chitosan and its derivatives and their unique properties are discussed. The antioxidant properties of chitosan have been presented and the need for more work targeted towards harnessing the antioxidant property of chitosan has been emphasized. Some portions of the crustacean waste are being converted to chitosan; the possibility that all of the waste can be used for harnessing this versatile multifaceted product chitosan is projected in this review. The future of chitosan recovery from marine crustacean wastes and the need to improve in this area of research, through the inclusion of nanotechnological inputs have been listed under future perspective.

Phoenix dactylifera L. Seed Extract Exhibits Antioxidant Effects and Attenuates Melanogenesis in B16F10 Murine Melanoma Cells by Downregulating PKA Signaling

Background: The mode of action of Phoenix dactylifera seed extract in skin care has never been explored. Methods: P. dactylifera L. seeds were extracted by ultrasonic extraction. The antioxidant characteristics of the extract were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-di-(3-ethylbenzthiazoline sulfonic acid) (ABTS⁺) assays and scavenging methods. The total phenolic content, reducing capacity, iron (II) ion-chelation, and intracellular reactive oxygen species (ROS)-scavenging capacities were also investigated. The effects of P. dactylifera L. seed extract on melanogenesis were evaluated spectrophotometrically by a mushroom tyrosinase activity assay, determination of intracellular tyrosinase activity, and melanin content. The expression levels of melanogenesis-related proteins were analyzed by Western blotting. Results: The results revealed that the P. dactylifera L. seed extract exerted apparent antioxidant capacity and significantly decreased intracellular ROS content at concentrations of 0.245 and 0.49 (mg/mL). Furthermore, the extract decreased the expression of melanocortin 1 receptor (MC1R), microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP1), and tyrosinase-related protein-2 (TRP2), and inhibited melanogenesis in B16F10 cells. Conclusions: Our results revealed that P. dactylifera L. seed extract attenuated melanogenesis in B16F10 cells by downregulating protein kinase A (PKA) signaling pathways. Hence, the extract could be used as a type of skin-whitening agent in skin care products.

Reducing Sugar, Total Phenolic Content, and Antioxidant Potential of Nepalese Plants

The aim of the present study was to investigate the reducing sugar, total phenolic content, and in vitro antioxidant activity of 70% (v/v) ethanolic extract of seven medicinal plants grown in Nepal. The reducing sugar content and total phenolic content were determined by 3,5-dinitrosalicylic acid (DNSA) and the Folin–Ciocalteu method, respectively. The in vitro antioxidant activity was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. The reducing sugar content of the studied plant samples ranged from 6.89 ± 2.44 to 674.13 ± 2.43 mg GE/g dry extract weight and the total phenolic content ranged from 14.87 ± 0.41 to 281.71 ± 1.47 mg GAE/g dry extract weight. The reducing sugar and total phenolic content were found highest in Ficus glaberrima. Antioxidant activity was found highest in Melastoma malabathricum (IC₅₀value = 6.27 μg/mL), followed by F. glaberrima (IC₅₀value = 11.7 μg/mL). A positive and significant correlation was found between (i) total phenolic content and reducing sugar content and (ii) total phenolic content and antioxidant activity. The present study is the first study for the analysis of reducing sugar content of selected plants and for the scientific exploration of F. glaberrima. The present result suggests that the various parts of these studied plants could be assumed as a rich source of biologically active compounds and considered beneficial for the food and pharmaceutical industries.

A water-soluble polysaccharide from Anethum graveolens seeds: Structural characterization, antioxidant activity and potential use as meat preservative

A novel water-soluble polysaccharide named AGP1 was successfully isolated from seeds of Anethum graveolens by hot water extraction and further purified by DEAE-Sepharose chromatography. AGP1 has a relative molecular weight of 2.1 10⁴ Da determined by Ultra-high-performance liquid chromatography (UHPLC). The AGP1 characterization was investigated by chemical and instrumental analysis including gas chromatography mass spectrometry (GC-MS), Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction. Results showed that AGP1 was mainly composed of glucose, galactose, mannose and arabinose in a molar percent of 54.3, 23.8, 14.7 and 7.2, respectively. The thermogravimetry analysis (TGA) and the differential scanning calorimetry (DSC) were used and showed that AGP1 has good thermal stability until 275 °C. Moreover, the purified polysaccharide demonstrated an appreciable in vitro antioxidant potential. The addition of the AGP1, particularly at 0.3% (w/w), in turkey sausages instead of ascorbic acid, as preservative, reduced the lipid peroxidation, preserved the pH and color and improved the bacterial stability during cold storage at 4 °C for 12 days. Overall, the results showed that the AGP1 deserves to be developed as functional and bioactive components for the food and nutraceutical industries.

In vitro antioxidant and antimicrobial potential of Sterculia urens Roxb. root extract and its bioactive phytoconstituents evaluation

Background

The plant Sterculia urens Roxb. of Malvaceae family is comparatively understudied. Genus Sterculia is widely recognized by its phytomedicinal and ethnomedicinal attributes. The study is aimed to evaluate the qualitative analysis, Fourier transform infrared (FT-IR), thin layer chromatography (TLC), total phenolic content (TPC), antioxidant and antimicrobial activities of the crude hydro-methanolic extract of S. urens root.

Results

The antioxidant activity, antimicrobial assay for clinical isolates, and TPC were measured by DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging activity, agar well diffusion method, and Folin–Ciocalteu assay respectively. Hydro-methanolic extract confirmed the presence of alkaloids, flavonoids, tannins, phenols, saponins, steroids, and glycosides as primary and secondary metabolites, which was later confirmed by TLC. FT-IR spectroscopy revealed the presence of alkanes, alkenes, alkyl halides, halogen compounds, primary alcohol, tertiary alcohol, aldehyde, aromatic amine, secondary amines, amide group, and carboxylic acid. The crude extract was composed of a significant quantity of total phenolic content with 705 ± 0.40 mg GAE/g. Synergistically, the IC50 value of the crude extract and ascorbic acid was found to be 27.055 μg/ml and 37.244 μg/ml, respectively, which suggests that root extract possesses strong antioxidant properties. The majority of the microbial strains exhibited varying degrees of sensitivity to the root extract with a notable inhibitory effect against Escherichia coli, Klebsiella pneumoniae, and Penicillium glaucum.

Conclusion

The findings of this analysis suggest that the hydro-methanolic extract from S. urens root exhibit antioxidant activity quantified by its ability to scavenge DPPH; antimicrobial activity displayed appreciable microbial sensitivity. These properties are associated with the presence of high phenolic content, different secondary metabolites, and their functional groups. The results are suggestive that S. urens root is rich in bioactive compounds, which serve as a novel natural source for potential therapeutic applications.

Graphical abstract

Potato peel extracts as an antimicrobial and potential antioxidant in active edible film

Potato peel is phenolic-rich plant byproduct that has multiple biological functions. The study explores the antimicrobial efficiency of the peel and its antioxidant potential incorporated with potato starch film. Antimicrobial sensitivity test using microdilution and diffusion test revealed positive response in Escherichia coli, Salmonella enterica, and Staphylococcus aureus with minimum inhibitory concentration, 7.5 ± 2, 5.8 ± 2, and 4.7 ± 1 mg/ml, respectively, but had a negative response for Klebsiella pneumoniae and Listeria monocytogenes. HPLC analysis revealed that caffeic, chlorogenic, and neochlorogenic acids are the main chemical compounds found in potato peel extract and responsible for its antimicrobial property. The scavenging ability and phenolic content in the active film range from 10 to 22 mg GAE/g of the dried film with 24%-55% of inhibition, respectively. The scanning electron microscope of the starch film showed homogeneously and ordered structure; however, some cracks and pores shown in the active film. The simulation experiment of phenols migration from the film into fatty and aqueous foods showed higher concentration in aqueous and less in the fatty foods. Therefore, potato peel extract has antibacterial as well as antioxidant property and incorporating with potato starch produce an active film which can be used as an alternative technology for active food packaging.

Bergenia pacumbis from Nepal, an astonishing enzymes inhibitor

BACKGROUND

The Bergenia species are perennial herbs native to central Asia, and one of the most promising medicinal plants of the family Saxifragaceae which are popularly known as 'Pashanbheda'. The aim of this study was to evaluate antioxidant and α-amylase, α-glucosidase, lipase, tyrosinase, elastase, and cholinesterases inhibition potential of Bergenia pacumbis of Nepali origin collected from the Karnali region of Nepal.

METHODS

The sequential crude extracts were made in hexane, ethyl acetate, methanol, and water. Antioxidant activities were analyzed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay. The α-amylase, α-glucosidase, lipase, tyrosinase, elastase, acetylcholinesterase, and butyrylcholinesterase inhibition were analyzed by the 3,5-Dinitrosalicylic acid (DNSA), p-Nitrophenyl-α-D-glucopyranoside (p-NPG), 4-nitrophenyl butyrate (p-NPB), l-3,4-dihydroxyphenylalanine (L-DOPA), N-Succinyl-Ala-Ala-p-nitroanilide (AAAPVN), acetylthiocholine, and butyrylcholine as a respective substrate. The major metabolites were identified by high performance liquid chromatography with electron spray ionization- quadrupole time-of-flight mass spectrometry (HPLC-ESI-QTOF-MS) profiling.

RESULTS

Our results revealed the great antioxidant ability of crude extract of B. pacumbis in ethyl acetate extract against both DPPH (IC50 = 30.14 ± 0.14 μg/mL) and ABTS (IC50 = 17.38 ± 1.12 μg/mL). However, the crude methanol extract of B. pacumbis showed the comparable enzymes inhibitions with standard drugs; α-amylase (IC50 = 14.03 ± 0.04 μg/mL), α-glucosidase (IC50 = 0.29 ± 0.00 μg/mL), lipase (IC50 = 67.26 ± 0.17 μg/mL), tyrosinase (IC50 = 58.25 ± 1.63 μg/mL), elastase (IC50 = 74.00 ± 3.03 μg/mL), acetylcholinesterase (IC50 = 31.52 ± 0.58 μg/mL), and butyrylcholinesterase (IC50 = 11.69 ± 0.14 μg/mL). On the basis of HPLC-ESI-QTOF-MS profiling of metabolites, we identified major compounds such as Bergenin, Catechin, Arbutin, Gallic acid, Protocatechuic acid, Syringic acid, Hyperoside, Afzelechin, Methyl gallate, Paashaanolactone, Astilbin, Quercetin, Kaempferol-7-O-glucoside, Diosmetin, Phloretin, and Morin in methanol extract which has reported beneficial bioactivities.

CONCLUSION

Our study provides a plethora of scientific evidence that the crude extracts of B. pacumbis from Nepalese origin in different extracting solvents have shown significant potential on inhibiting free radicals as well as enzymes involved in digestion, skin related problems, and neurological disorders compared with the commercially available drugs.

Gas chromatography-mass spectrometry (GM-MS) analysis and biological activities of the aerial part of Cleome amblyocarpa Barr. and Murb

Cleome amblyocarpa Barr. and Murb is a medicinal plant widespread in North Africa and widely used in Tunisia to treat diabetes and colic. The non-volatile (polyphenols, flavonoids, tannins, and flavonols) and volatile compounds (GC-MS) of C. amblyocarpa leaves and stems have been studied. The antioxidant, antimicrobial, analgesic, and cytotoxic activities of hydroalcoholic extracts of C. amblyocarpa leaves and stems were also investigated. The major volatile components were β-caryophyllene (46.9%), eugenol (25.6%), ethyl 3-methylpentanoate (16.2%), 7-epi-silphiperfol-5-ene (11.0%), and α-copaene (7.0%). The antioxidant activity has been evaluated using various in vitro assays, such as DPPH free radical scavenging activity, iron-chelating capability, and ability to inhibit lipid peroxidation (TBARS). The antibacterial and antifungal effectiveness of leaves and stems parts of Cleome amblyocarpa were investigated by means of the disc diffusion and microdilution techniques. The in vitro cytotoxicity of the hydroalcoholic extract of C. amblyocarpa on A549 and H1299 lung adenocarcinoma cells was determined using the crystal violet assay. The acute toxicity of the extracts on Swiss albino mice at the doses of 3000, 1500, and 500 mg/kg body weight was evaluated. The analgesic effect of leaves and stems extract was also determined by means of the acetic acid induced writhing test. The results indicated that the leaves have higher phenols, and flavonoids contents and potential antioxidant, antimicrobial, and anticancer activities in comparison to stem. In addition, the aerial part of C. amblyocarpa did not cause signs of toxicity or death in animals at doses up to 3000 mg/kg and have a significant analgesic activity.

The novel peptides ICRD and LCGEC screened from tuna roe show antioxidative activity via Keap1/Nrf2-ARE pathway regulation and gut microbiota modulation

In this study, a high-throughput strategy combined with MALDI TOF/TOF-MS and Discovery Studio 2017 was developed to screen peptides with certain functions from hydrolysate. Two dominant peptides, Ile-Cys-Arg-Asp (ICRD) and Leu-Cys-Gly-Glu-Cys (LCGEC), were predicted to have antioxidant activity by Discovery Studio 2017. Then the activity in vitro of peptides had been confirmed via DPPH assay. Both two peptides decreased apoptosis induced by UVB treatment in HaCaT cells and altered Keap1/Nrf2-ARE pathway transcription. Furthermore, the antioxidant activity of LCGEC was achieved after 6-week treatment in mice via regulating the Keap1/Nrf2-ARE pathway, inhibiting the release of proinflammatory cytokines, increasing the abundance of 3-indolepropionic acid and short-chain fatty acids production in feces and modulating gut microbiota composition. This study provided two tuna roe peptides with in vitro and in vivo antioxidant activity.

Management of Iron Overload in Resource Poor Nations: A Systematic Review of Phlebotomy and Natural Chelators

Iron is an essential element and the most abundant trace metal in the body involved in oxygen transport and oxygen sensing, electron transfer, energy metabolism, and DNA synthesis. Excess labile and unchelated iron can catalyze the formation of tissue-damaging radicals and induce oxidative stress. English abstracts were identified in PubMed and Google Scholar using multiple and various search terms based on defined inclusion and exclusion criteria. Full-length articles were selected for systematic review, and secondary and tertiary references were developed. Although bloodletting or phlebotomy remains the gold standard in the management of iron overload, this systematic review is an updated account of the pitfalls of phlebotomy and classical synthetic chelators with scientific justification for the use of natural iron chelators of dietary origin in resource-poor nations.

Waste Pomelo (Citrus Maxima) Peels – A Natural Source of Antioxidant and Its Utilization in Peanut Oil for Suppressing the Development of Rancidity

The antioxidant activity of pomelo peels was evaluated with different organic solvents. Minimum yield (11.1%) was obtained with chloroform +methanol (2:1), maximum yield (21.6%) with methanol whereas (15.9%) with ethanol and (12.7%) with hexane were observed. The maximum scavenging activity of (ethanolic pomelo peel extract) 88.8 % was observed at 14mg/ml concentration. Antioxidant activity of ethanolic pomelo peel extract was evaluated by calculating free fatty acid, iodine value and p-Anisidine value of peanut oil during 21 days of storage period at room temperature. Samples were drawn and analyze periodically after 7 days and after 21 days of storage, peanut oil containing 1500 and 2000 ppm pomelo peel extract, be revealed lower free fatty acid values (2.66, 2.15%), and p- anisidine value (6.6, 4.68) and higher iodine value (52.8, 51.46) than control peanut oil sample (free fatty acid 9.32%, p- anisidine value 9.85 and iodine value 33.9). From the results, it could be concluded that natural antioxidants extracted from pomelo peel could be added to fat and oil to increase their shelf life by preventing oxidative rancidity.

Novel Amide Derivatives as Potent Tyrosinase Inhibitors; In-vitro, In-vivo Antimelanogenic Activity and Computational Studies

BACKGROUND

Tyrosinase is involved in the melanin biosynthesis and the abnormal accumulation of melanin pigments leading to hyperpigmentation disorders. Controlling the melanogenesis could be an important strategy for treating abnormal pigmentation.

METHODS

In the present study, a series of amide derivatives (3a-e and 5a-e) were synthesized aiming to inhibit tyrosinase activity and melanin production. All derivatives were screened for tyrosinase inhibition in a cell-free system. The possible interactions of amide derivatives with tyrosinase enzyme and effect of these interactions on tyrosinase structure were checked by molecular docking in silico and by Circular Dichroism (CD) studies, respectively. The most potent amide derivative (5c) based on cell-free experiments, was further tested for cellular ROS inhibition and for tyrosinase activity using mouse skin melanoma (B16F10) cells.

RESULTS

The tyrosinase inhibitory concentration (IC50) for tested compounds was observed between the range of 68 to 0.0029 µg/ml with a lowest IC50 value of compound 5c which outperforms the reference arbutin and kojic acid. The cellular tyrosinase activity and melanin quantification assay demonstrate that 15µg/ml of 5c attenuates 36% tyrosinase, 24% melanin content of B16F10 cells without significant cell toxicity. Moreover, the zebrafish in vivo assay reveals that 5c effectively reduces melanogenesis without perceptible toxicity. Furthermore, the molecular docking demonstrates that compound 5c interacts with copper ions and multiple amino acids in the active site of tyrosinase with best glide score (-5.387 kcal/mol), essential for mushroom tyrosinase inhibition and the ability to diminish the melanin synthesis in-vitro and in-vivo.

CONCLUSION

Thus, we propose compound 5c as a potential candidate to control tyrosinase rooted hyperpigmentation in the future.

Synthesis, computational studies, tyrosinase inhibitory kinetics and antimelanogenic activity of hydroxy substituted 2-[(4-acetylphenyl)amino]-2-oxoethyl derivatives

The over expression of melanogenic enzymes like tyrosinase caused many hyperpigmentaion disorders. The present work describes the synthesis of hydroxy substituted 2-[(4-acetylphenyl)amino]-2-oxoethyl derivatives 3a-e and 5a-e as antimelanogenic agents. The tyrosinase inhibitory activity of synthesized derivatives 3a-e and 5a-e was determined and it was found that derivative 5c possesses excellent activity with IC50 = 0.0089 µM compared to standard kojic acid (IC50 = 16.69 µM). The presence of hydroxyl groups at the ortho and the para position of cinnamic acid phenyl ring in compound 5c plays a vital role in tyrosinase inhibitory activity. The compound 5d also exhibited good activity (IC50 = 8.26 µM) compared to standard kojic acid. The enzyme inhibitory kinetics results showed that compound 5c is a competitive inhibitor while 5d is a mixed-type inhibitor. The mode of binding for compounds 5c and 5d with tyrosinase enzyme was also assessed and it was found that both derivatives irreversibly bind with target enzyme. The molecular docking and molecular dynamic simulation studies were also performed to find the position of attachment of synthesized compounds at tyrosinase enzyme (PDB ID 2Y9X). The results showed that all of the synthesized compounds bind well with the active binding sites and most potent derivative 5c formed stable complex with target protein. The cytotoxicity results showed that compound 5c is safe at a dose of 12 µg/mL against murine melanoma (B16F10) cells. The same dose of 5c was selected to determine antimelanogenic activity; the results showed that it produced antimelenogenic effects in murine melanoma (B16F10) cells. Based on our investigations, it was proposed that compound 5c may serve as a lead structure to design more potent antimelanogenic agents.

Study on Antioxidant Activity of Amino Acids at Frying Temperatures and Their Interaction with Rosemary Extract, Green Tea Extract, and Ascorbic Acid

Some amino acids have strong antioxidant activity in frying oil. This study aimed to obtain further information including antioxidant activity at different concentrations and interactions with rosemary extract, green tea extract, and ascorbic acid. Antioxidant activity of arginine, cysteine, lysine, methionine, and tryptophan was examined by increasing the concentration in soybean oil (SBO) at 180 °C within the concentration range of 0 to 15 mM. These amino acids showed increased activity with increasing concentration without showing prooxidant activity at the given concentration range. Addition of 15 mM methionine did not inhibit the prooxidant activity of α-tocopherol at high concentrations in SBO while it significantly increased the activity at each concentration of α-tocopherol. Methionine showed an additive effect with a commercial rosemary extract while lysine had an antagonistic interaction in SBO at the total concentration of 5.5 mM. Mixtures of green tea extract and methionine did not show better activity than methionine alone in SBO and stripped SBO. (-)-Epigallocatechin gallate, the major active component in green tea, showed a synergistic effect with methionine in stripped SBO but there was no significant interaction effect in SBO. Although ascorbic acid had a synergistic effect with methionine in stripped SBO, it showed a significant antagonistic effect in SBO. Methionine had strong antioxidant activity in six other vegetable oils showing a moderate correlation (R² = 0.45 to 0.52) with the ratio of unsaturated fatty acids to saturated fatty acids indicating the effectiveness may be related to the fatty acid composition of oil. PRACTICAL APPLICATION: Some amino acid such as methionine and lysine showed stronger antioxidant activity than the leading commercial natural antioxidant, rosemary extract. These amino acids showed great potential as a natural antioxidant in frying. The price of food-grade L-methionine is generally lower than rosemary extract and green tea extract. This paper provides information on the concentration effect and interactions with currently used antioxidants such as tocopherols, rosemary extract, green tea extract, and ascorbic acid.

Influence of the Physical State of Spray-Dried Flavonoid-Inulin Microparticles on Oxidative Stability of Lipid Matrices

The effect of the physical state of flavonoid-inulin microparticles (semi-crystalline/amorphous) on the oxidative stability of lipid matrices was studied. Epicatechin (E) and quercetin (Q) microparticles with inulin were formulated at two infeed temperatures (15 °C and 90 °C) by spray drying. X-ray diffraction analyses showed that flavonoid-inulin microparticles obtained at feed temperature of 15 °C were semi-crystalline (E-In-15, 61.2% and Q-In-15, 60%), whereas those at 90 °C were amorphous (Q-In-90, 1.73 and Q-In-90 2.30%). Semi-crystalline state of flavonoid-inulin microparticles enhanced the EE (68.8 and 67.8% for E and Q, respectively) compared to amorphous state (41.6 and 51.1% for E and Q, respectively). However, amorphous Q-microparticles showed the highest antioxidant activity both in methyl linoleate and sunflower oil, increasing the induction period and decreasing the polar compounds and polymer triglyceride formation during long-term oxidation study. Therefore, the physical state of spray-dried flavonoid-inulin microparticles may determine their antioxidant activity in lipid matrices.

Protective Effects of Novel Antioxidant Peptide Purified from Alcalase Hydrolysate of Velvet Antler Against Oxidative Stress in Chang Liver Cells in Vitro and in a Zebrafish Model In Vivo

Velvet antler has a long history in traditional medicine. It is also an important healthy ingredient in food as it is rich in protein. However, there has been no report about antioxidant peptides extracted from velvet antler by enzymatic hydrolysis. Thus, the objective of this study was to hydrolyze velvet antler using different commercial proteases (Acalase, Neutrase, trypsin, pepsin, and α-chymotrypsin). Antioxidant activities of different hydrolysates were investigated using peroxyl radical scavenging assay by electron spin resonance spectrometry. Among all enzymatic hydrolysates, Alcalase hydrolysate exhibited the highest peroxyl radical scavenging activity. Alcalase hydrolysate was then purified using ultrafiltration, gel filtration, and reverse-phase high performance liquid chromatography. The purified peptide was identified to be Trp-Asp-Val-Lys (tetrapeptide) with molecular weight of 547.29 Da by Q-TOF ESI mass spectroscopy. This purified peptide exhibited strong scavenging activity against peroxyl radical (IC₅₀ value, 0.028 mg/mL). In addition, this tetrapeptide showed significant protection ability against AAPH-induced oxidative stress by inhibiting of reactive oxygen species (ROS) generation in Chang liver cells in vitro and in a zebrafish model in vivo. This research suggests that the tetrapeptide derived from Alcalase-proteolytic hydrolysate of velvet antler are excellent antioxidants and could be effectively applied as functional food ingredients and pharmaceuticals.

Effect of Aged and Fermented Garlic Extracts as Natural Antioxidants on Lipid Oxidation in Pork Patties

The aim of this study was to investigate the natural antioxidant activity of raw garlic (RG), aged black garlic (AG), and garlic fermented with Bacillus subtilis (FG) extracts on pork patty lipid oxidation throughout refrigerated storage. The total polyphenol, total flavonoid content, 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity of three different types of garlic extracts were measured. The total phenolic and flavonoid content of AG was significantly higher than that of FG and RG; FG also showed a significantly higher total phenolic content than that of RG (p<0.05). The DPPH and ABTS radical scavenging activity of AG and FG was significantly higher than that of RG and that of AG was significantly higher than that of FG (p<0.05). To investigate the effect of processed garlic extracts on pork patty lipid oxidation, freeze-dried extracts of RG, FG, and AG were added to the patties at levels of 0.5% (w/w). Patties containing 0.01% (w/w) ascorbic acid (AA) and patties without treatment (CON) were compared with patties containing garlic extracts. The pH value, 2-thiobarbituric acid reactive substances value, and volatile basic nitrogen value of pork patties containing AG and FG extracts were significantly decreased compared to the other groups (CON, AA, and RG; p<0.05). Taken together, these results suggest that AG and FG extracts possess strong antioxidative activity and can serve as natural antioxidative additives to prevent pork patty lipid oxidation.

Impact of Phospholipid-Tocopherol Combinations and Enzyme-Modified Lecithin on the Oxidative Stability of Bulk Oil

Phosphatidylethanolamine (PE) and phosphatidylserine (PS) have been shown to increase the antioxidant activity of α-tocopherol. This study investigated the ability of PE or PS to increase the antioxidant activity of different tocopherol homologues in bulk oil. In addition, the ability of a phospholipase-D-modified lecithin (high in PE) to increase the activity of α-tocopherol was determined. Results showed that PE was much more effective than PS at increasing the activity of the tocopherol homologues. The combination of mixed tocopherols with PE presented the greatest increase in antioxidant activity, with hydroperoxides and hexanal lag phases increasing 54 and 53 days compared to the mixed tocopherols alone. Phospholipase-D-modified lecithin increased the antioxidant activity of α-tocopherol in stripped bulk oil as well as a commercially refined oil with no added tocopherols. The study indicates that PE is a powerful tool to increase the antioxidant activity of tocopherols in bulk oil and that modification of lecithin to increase the PE concentration could be a commercially viable option to functionalize lecithin, so that its ability to inhibit lipid oxidation increases in bulk oils.

Purification and identification of an antioxidant peptide from perilla seed (Perilla frutescens) meal protein hydrolysate

This study aimed to obtain antioxidant peptides from perilla seed meal (PSM), which is normally discarded as an industrial waste during seed oil extraction. PSM protein was hydrolyzed using trypsin and fractionated by ultrafiltration. Molecular weight fraction (<3 kDa) with the highest antioxidant activity was purified using prep-HPLC and analytical HPLC. The purification fold of the peptide (fraction V) obtained from PSM protein hydrolysate on DPPH radical scavenging activity, ABTS radical scavenging activity, and reducing power was 1.79-, 1.59-, and 1.81-fold, respectively, after the three-step purification procedure. The sequence of the purified peptide from fraction V that exhibited free radical scavenging activity and reducing power was identified as Ile-Ser-Pro-Arg-Ile-Leu-Ser-Tyr-Asn-Leu-Arg (1,330.77 Da). These results demonstrate that PSM protein, a by-product from the oil seed extraction, can be used as a source of natural antioxidant peptides for food and/or nutraceutical applications.

Antifungal and Antioxidant Properties of Chitosan Polymers Obtained from Nontraditional Polybius henslowii Sources

Chitin was extracted from Polybius henslowii, a swimming crab, captured in large quantities throughout the Portuguese coast by purse seine vessels as bycatch. After standard chitin extraction procedures, water-soluble chitosan products were obtained via two different methods: (1) N-acetylation with the addition of acetic anhydride and (2) a reaction with hydrogen peroxide. The chemical structure and molecular weight of chitosan derivatives, water-soluble chitosan (WSC) and chitooligosaccharides (COS), were confirmed by Fourier Transform Infrared Spectroscopy (FT-IR) and gel permeation chromatography (GPC). Antioxidant and metal chelation activities were evaluated, and the growth inhibition capacity was tested on four phytopatogens. The chitooligosaccharides from pereopods (pCOS) and shell body parts (sCOS) inhibited all fungal species tested, particularly Cryphonectria parasitica with 84.7% and 85.5%, respectively. Both radical scavenging and antifungal activities proved to be dose-dependent. Chitooligosaccharides with a low molecular weight (2.7, 7.4, and 10.4 Kg·mol⁻¹) showed the highest activity among all properties tested. These results suggested that chitosan derivatives from P. henslowii raw material could potentially be used against phytopathogens or as ingredient in cosmetics and other products related to oxidative stress.

Phytochemical, antioxidant, anti-proliferative and antimicrobial properties of Catharanthus roseus root extract, saponin-enriched and aqueous fractions

Catharanthus roseus (L.) G. Don (C. roseus) is a well-known medicinal plant for its source of alkaloids solely found in the leaves. Other parts including the root are usually discarded after the alkaloid extraction. This study sought to investigate phytochemical profiles, antioxidant, antimicrobial and cytotoxic properties of the C. roseus root extract (RE) and its two sub-fractions including saponin-enriched (SE) and aqueous (AQ) fractions. The results showed that the RE was a rich source of saponins (1744.44 mg ESE/g) and phenolics (51.27 mg GAE/g), which comprised of gallic acid (25.74 mg/g), apigenin (1.45 mg/g) and kaempferol (1.58 mg/g). The SE fraction was enriched with 31% of saponins and 63% of phenolics higher than those of the RE; whereas the concentrations of saponins and phenolics of the AQ fraction were lower than those of the RE by 40% and 74%, respectively. The content of gallic acid in the SE fraction was 1.4-fold and 1.5-fold higher than those of the RE or AQ fraction, respectively. The SE fraction demonstrated potent antioxidant capacity, which was significantly higher than the RE or AQ fraction, and also exhibited strong anti-proliferative activity against 11 cancer cell lines including A2780 (ovarian), H460 (lung), A431 (skin), MIA PaCa-2 (pancreas), Du145 (prostate), HT29 (colon), MCF-7 (breast), BE2-C (neuroblastoma), SJ-G2, U87 and SMA (glioblastoma) with low GI₅₀ values (≤ 2.00 µg/mL). The SE fraction was also shown to effectively inhibit the growth of both bacteria (Escherichia coli, Enterobacter aerogenes and Staphylococccus lugdunensis) and fungi (Candida albicans and Aspergillus niger). These findings warrant further investigation to isolate major compounds from the SE fraction and further test their antioxidant, anticancer and antimicrobial activities.

Chemical Composition, Olfactory Evaluation and Antioxidant Effects of the Leaf Essential Oil of Corymbia citriodora (Hook) from China

The chemical composition of a sample of lemon eucalyptus essential oil ( Corymbia citriodora) from China was determined by GC/FID and GC/MS. Citronellal (76.3%), citronellol (5.7%) and neo-isopulegol (5.5%) were the major components. The odor of the sample was evaluated as fresh, citrus-like and mildly fruity, with a pleasant woody background note.

Lemon eucalyptus oil was found to exhibit antiradical activity with respect to DPPH and hydroxyl (OH•) radicals. The effect exercised on OH• radicals significantly exceeded that observed for the DPPH radical – the respective concentrations for 50% inhibition of the radicals were 0.38 μg/mL for OH• and 344.0 μg/mL for DPPH. Furthermore, the essential oil revealed antioxidant activities in a model system comprised of a linoleic acid emulsion. At a concentration of 0.1%, inhibition of conjugated dienes-formation by 59.8% was observed and the formation of secondary oxidized products of linoleic acid by 84.7%.

Essential Oils from Lamiaceae Species as Promising Antioxidant and Antimicrobial Agents

Overproduction of free radicals in organisms and lipid peroxidation in cell membranes have been implicated in various pathophysiological disorders, including cardiovascular diseases, atherogenesis, mutagenesis, diabetes, etc. Furthermore, the oxidation of lipids in food, cosmetic and pharmaceutical products, together with the growth of undesirable microorganisms result in off-flavour, spoilage and deterioration, rendering such products unfit for human consumption. Increasing environmental pressure for industry to use “clean technology” and to utilize sustainable sources of materials for the manufacturing process, have concentrated recent investigations towards natural sources of antioxidants and antimicrobials. Although plant phenolics have been recognized as the most powerful natural antioxidants, recent studies suggest that terpenoids in essential oil could also contribute to the overall antioxidant capacity of many spice plants. This review summarizes the scientific evidence regarding the antioxidative and antimicrobial efficiency of essential oils of aromatic plants belonging to the Lamiaceae family, and consequently their possible utilization as safe and healthy food supplements.

Effect of Allium hookeri Root on Physicochemical, Lipid, and Protein Oxidation of Longissimus Dorsi Muscle Meatball

The antioxidant effects of Allium hookeri root (AHR) were investigated by evaluating lipid and protein oxidation in meatballs during refrigerated storage at 4±1℃. AHR was mixed at concentrations of 0.5% (w/w, T2) and 1% (w/w, T3) with minced longissimus dorsi muscle. Meatballs containing AHR (T2 and T3) were compared to those containing 0.05% (w/w) ascorbic acid (T1) as a reference and without antioxidant as a control. The 2-thiobarbituric acid reactive substances (TBARS) value, disulfide bond formation, carbonyl contents, and volatile basic nitrogen (VBN) value of T2 were lower than those of the control during storage (p<0.05). The pH values of T2 and T3 were higher than that of the control (p<0.05). Texture profile analysis of T2 revealed a lower value compared to the control (p<0.05). Therefore, the VBN value, TBARS value, disulfide bond formation, and carbonyl content in meatball containing AHR were lower than those of the control meatball. These results indicate that AHR improves the quality of meat products and functions as an antioxidant.