Variation of Polyphenol Content and Antioxidant Activity in Some Bilberry (Vaccinium myrtillus L.) Populations from Romania

Fruits of bilberry (Vaccinium myrtillus L.) are valued mainly for their nutraceutical properties, and are among the fruits with the highest antioxidant activity due to their high content of phenolic compounds. The aim of this research was to assess the total polyphenol content and antioxidant activity of fruits in six wild bilberry populations from two regions of Romania over three years. The total polyphenol content was determined according to the Folin–Ciocalteu modified method, while the antioxidant activity was evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay. The Padis and Raul Lung populations registered the highest values of polyphenol content and antioxidant activity, as such the fruits of these bilberry populations could be considered potential sources of antioxidants for direct consumption or for use as ingredients for food products or food supplements. Significant variation of total polyphenol content and antioxidant activity was observed both between populations from the same region and from different regions. The low level of broad sense heritability for total polyphenol content and antioxidant activity associated with the high effects of year, and population–year interaction indicates that the accumulation of polyphenols in bilberry fruits is influenced by changes in environmental conditions.

Screening of the Potential Bioactivities of Pennyroyal (Mentha pulegium L.) Essential Oil

Increasing resistance of pathogens towards conventional antibiotics presents a major threat to public health because it reduces the effectiveness of antibiotic treatment. Mentha pulegium L., also known as pennyroyal, is an aromatic herb that belongs to the family Lamiaceae. Its essential oil has been traditionally used in medicine, aromatherapy, and cosmetics. The purpose of this work was to study the chemical composition of a pennyroyal essential oil and to evaluate their bioactivities, specifically, antioxidant, antimicrobial, anti-quorum sensing, and anti-inflammatory. A special focus was given to the antibacterial activity of the essential oil against Acinetobacter baumannii. The chemical composition of the essential oil was studied by GC-MS/GC-FID. The DPPH free radical scavenging assay and the β-carotene/linoleic acid system were used to evaluate the antioxidant properties. The antimicrobial and anti-quorum sensing activities were evaluated by disk diffusion assays and complemented with optical microscopy observations. The results showed that pulegone was the major compound (88.64%) of the pennyroyal essential oil. Regarding the antimicrobial activity, the action against Acinetobacter baumannii stands out, which, together with the capacity of the essential oil to inhibit the quorum sensing mechanisms, may suggest the use of the pennyroyal essential oil to further develop surface disinfectants for hospitals.

ALOE IRAFENSIS AN ENDEMIC PLANT OF YEMEN: PHYTOCHEMICAL SCREENING, ANTIBACTERIAL, ANTIOXIDANT, AND WOUND-HEALING ACTIVITIES

Objectives: The objectives of the study were to determine the phytochemical constituents and assess the antibacterial, antioxidant, and wound-healing properties of the methanol extracts of Aloe irafensis. Methods: Methanol extracts of A. irafensis’s latex, gel, and green skin were screened for their phytochemical constituents. All three extracts were investigated regarding their antibacterial potential using disc diffusion and microdilution assays, and their antioxidant activity using 2,2-diphenyl-1- picrylhydrazyl free-radical scavenging assay. Histopathological study of wound healing area was performed for the latex extract in male albino rats. Results: The methanol extracts of A. irafensis revealed the presence of carbohydrates, steroids, phenols, tannins, and anthrones. The latex extract showed greater inhibition zones against Staphylococcus aureus and Pseudomonas aeruginosa (24 and 17 mm, respectively) and minimum inhibitory concentration values of 1.25 and 2.50 mg/ml, respectively. The latex extract showed the highest antioxidant activity (IC50 of 65.54 μg/ml), followed by green skin (IC50 of 89.48 μg/ml). The latex extract significantly accelerated the rate of wound healing in rats (p<0.01), compared to fucidin ointment, a reference control. Histological findings showed remarkably less scar width at wound closure site in the latex extract-treated wounds. Granulation tissue contained fewer inflammatory cells and more fibroblasts in wounds treated with the latex extract compared to those treated with the vehicle. Conclusion: A. irafensis latex extract is a potential source of bioactive compounds that can be used as antioxidant, antibacterial, and wound healing agents.

Phytochemical Screening and Antioxidant Activity of Salvia hispanica

Background: There is a growing interest worldwide to identify novel functional foods able to exert important biochemical activities with low or without toxic effect. Accordingly, the use of Salvia hispanica L. (chia) a Mexican herb, has tremendously grown as an agriculture crop owing to the nutritional and medicinal values. The objective of this study was to evaluate phytochemical composition of chia seeds and prove their claim for functional properties. Materials and Methods: The determination of total phenolic, flavonoid and condensed tannin contents of chia seeds were carried out by the Folin-Ciocalteu, the aluminum trichloride and the vanilline acid spectrometric methods. Antioxidant activities of chia seeds extracts were assessed using free radical scavenging assay DPPH, Ferric Reducing Antioxidant Potential FRAP and β-Carotene bleaching assay. Results: Chia seeds contain high levels of total phenolic and flavonoid contents 19.06±0.14 mg GAE/ g DW and 12.3±0.04 mg CE/g DW, respectively. The content of condensed tannins was estimated at 8.32±0.01 mg CE/g DW. The flavonoid extract showed a higher antioxidant potential against DPPH, FRAP and the bleaching of β-Carotene (0.27±0.00, 0.06±0.03 and 0.39±0.01 mg/mL, respectively). Conclusion: Following the obtained results, we should explore the use of this seeds in food products due its nutritional and chemical composition, possible human health benefits and role as a functional food.

The Rhythmic Growth Pattern of Microbes is Antithetical to Antioxidant Activity of Kombucha: A New Finding in Food Biochemistry

Background: Kombucha is a traditional, popular and probiotic health drink having strong antioxidant properties. Involvement of various bacteria and yeasts in kombucha fermentation have been previously described by several scientists. In this research, we aimed to determine the growth pattern of microbes involved in kombucha fermentation, using the orthodox turbidimetric method and a simultaneous determination of antioxidant activity regularly. Methods: This experiment was designed in a simple way to evaluate the interrelation between growth of microbes involved in kombucha fermentation and the rate of release of antioxidant molecules using spectrophotometric growth study and DPPH free radical scavenging assay. Results: In this research, some new characteristics of kombucha have been found regarding microbial fermentation. Moreover, we prepared broths using different types of sugars as carbon source for a comparative analysis. Significance: In all the broths, it was found that there is a negative correlation between rhythmic microbial growth pattern and antioxidant activity which is definitely a new finding in food science.

Syntheses and Structural Investigations of Penta-Coordinated Co(II) Complexes with Bis-Pyrazolo-S-Triazine Pincer Ligands, and Evaluation of Their Antimicrobial and Antioxidant Activities

Two penta-coordinated [Co(MorphBPT)Cl2]; 1 and [Co(PipBPT)Cl2]; 2 complexes with the bis-pyrazolyl-s-triazine pincer ligands MorphBPT and PipBPT were synthesized and characterized. Both MorphBPT and PipBPT act as NNN-tridentate pincer chelates coordinating the Co(II) center with one short Co-N(s-triazine) and two longer Co-N(pyrazole) bonds. The coordination number of Co(II) is five in both complexes, and the geometry around Co(II) ion is a distorted square pyramidal in 1, while 2 shows more distortion. In both complexes, the packing is dominated by Cl…H, C-H…π, and Cl…C (anion-π stacking) interactions in addition to O…H interactions, which are found only in 1. The UV-Vis spectral band at 564 nm was assigned to metal–ligand charge transfer transitions based on TD-DFT calculations. Complexes 1 and 2 showed higher antimicrobial activity compared to the respective free ligand MorphBPT and PipBPT, which were not active. MIC values indicated that 2 had better activity against S. aureus, B. subtilis, and P. vulgaris than 1. DPPH free radical scavenging assay revealed that all the studied compounds showed weak to moderate antioxidant activity where the nature of the substituent at the s-triazine core has a significant impact on the antioxidant activity.

INVESTIGATION OF ANALGESIC, ANTIOXIDANT, AND CYTOTOXIC PROPERTIES OF THE ETHANOLIC EXTRACT OF STREBLUS ASPER (ROOTS)

Objective: This study evaluated the analgesic, antioxidant, and cytotoxic effects of ethanolic extract of Streblus asper roots. Methods: Analgesic activities were carried out using paw licking and writhing tests. The extract was used at doses of 250 and 500 mg/kg per orally in Swiss albino mice of body weight 25–30 g. Antioxidant properties were investigated using 1, 1-diphenyl-1-picrylhydrazyl free-radical scavenging assay, total phenol content, total flavonoid content as well as reducing power capacity. The cytotoxic activity was determined by the Brine Shrimp lethality bioassay. Results: The ethanolic extract of S. asper roots showed a significant effect in the formalin test (p<0.01). They also exhibit the highest analgesia (p<0.01) in the acetic acid-induced writhing model as well. The extract possessed antioxidant effects in all the models. It possessed a good cytotoxic activity. Conclusion: The results suggested that S. asper root extract has a suitable analgesic, antioxidant effect as well as significant cytotoxic potential.

Green Synthesis and Characterization of Zinc Oxide Nanoparticles Using Mulberry Fruit and Their Antioxidant Activity

Biosynthesis of metal-oxide nanoparticles using plant extracts has been attracting increasing interest. In this study, we focused on the green synthesis of zinc oxide (ZnO) nanomaterials using zinc acetate as a precursor and mulberry fruit extract as a green reducing agent and determined the antioxidant activity. Powder X-ray diffraction and UV-Vis and Fourier Transform Infra-Red (FT-IR) spectroscopy were used for structure elucidation and to determine the crystallinity of the synthesized product. The morphology of samples was determined using Scanning Electron Microscopy (SEM). Our results indicated the successful synthesis of ZnO nanoparticles. SEM findings revealed the nanoparticles to be spherical; they were found to agglomerate and showed a narrow space between particles, which could be indicative of improved activity. The antioxidant activity of ZnO nanoparticles was determined using a 2,2-Diphenyl-1-Picryl-Hydrazyl (DPPH) free-radical scavenging assay taking into account time and concentration. Our results indicated that ZnO nanoparticles with mulberry fruit extract that were synthesized using green chemistry could effectively scavenge the free DPPH radicals, thereby confirming their superior antioxidant activity.

In Vitro Antioxidant and In Vivo Antidiabetic Properties of Citrus Maxima Leaf Extracts in Alloxan-Induced Swiss Albino Diabetic Mice

Aims: The current study aimed to explore in vitro antioxidant capacity and in vivo antidiabetic property of Citrus maxima leaf. Methods: Citrus maxima leaf extracts were prepared using methanol (MECML) and ethanol (EECML) in this study. Antioxidant capacity of both extracts was evaluated using total antioxidant capacity (TAC) assay, ferric reducing antioxidant power (FRAP) assay, DPPH free radical scavenging assay, and ABTS free radical scavenging assay. Cytotoxicity of MECML and EECML was assessed by brine shrimp lethality bioassay. To explore the in vivo antidiabetic property of MECML and EECML, diabetic mellitus (DM) was induced in Swiss albino mice by a single intraperitoneal injection of alloxan. Then diabetic mice were treated with both extracts for 28 days. Effects of both extracts on serum levels of glucose, liver function enzymes, and parameters of lipid profile associated with DM were evaluated. Results: In TAC and FRAP assays, MECML and EECML represented gradually increased reducing capacity in a dose-dependent manner. In DPPH and ABTS assays, both extracts showed notable free radical scavenging activity with lower IC50 values. Additionally, MECML and EECML showed very low toxicity with LC50 values of 80.46 and 105.59 μg/mL, respectively in brine shrimp lethality assay. Moreover, both extracts significantly augmented altered levels of serum glucose, parameters of lipid profile, SGPT, SGOT, and C-reactive protein with the treatment of MECML and EECML. Conclusion: This study suggests Citrus maxima leaf possesses significant antioxidant and antidiabetic properties and they might play a potential role to prevent diabetic mellitus and diabetic mellitus associated complications.

Nicotine metal complexes: synthesis, characterization and bioactivities of some main group and some transition metals

A number of some main group and transition metal nicotine complexes were synthesized and fully characterized using detailed structural and spectroscopic analysis techniques such as elemental analysis, molar conductivities, magnetic susceptibilities, IR, Raman and NMR techniques. Moreover, scanning electron micrographs and thermogravimetric analyses were also done. Cytotoxic activities of the binary nicotine metal complexes were tested and evaluated against HepG2 (human hepatocellular carcinoma), HPC3 (human prostate cancer), and HCT116 (human colorectal carcinoma) tumor cell lines. The antioxidant activities were examined by free radical scavenging assay. The antimicrobial activities of the synthesized complexes were evaluated against Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) microbes. The relationship between the chemical structure of the synthesized complexes and their biological influence as antimicrobial drugs was studied and evaluated. KEY WORDS: Nicotine metal complexes, Cytotoxicity, Antioxidant, Antimicrobial Bull. Chem. Soc. Ethiop. 2020, 34(3), 501-521. DOI: https://dx.doi.org/10.4314/bcse.v34i3.7