Yavuz Selim Cakmak

Antioxidant potentials and anticholinesterase activities of methanolic and aqueous extracts of three endemic Centaurea L. species

The methanol and aqueous extracts of three endemic Centaurea species (C. polypodiifolia var. pseudobehen, C. pyrrhoblephara and C. antalyense) were investigated for their antioxidant and cholinesterase inhibitory activities. The antioxidant activities of these extracts were evaluated by in vitro models including, phosphomolybdenum assay, free radical scavenging assays (DPPH and ABTS), β-carotene/linoleic acid test system, metal chelating assay, FRAP assay, ferric and cupric reducing power. Cholinesterase inhibitory activities were examined using Ellmans colorimetric method. Total phenol, flavonoid, and saponin contents were also measured. Among the six Centaurea extracts evaluated, the highest antioxidant abilities were obtained from C. polypodiifolia var. pseudobehen. Methanolic extracts from C. polypodiifolia var. pseudobehen and C. antalyense had a noticeable inhibition towards AChE and BChE. These findings suggest that Centaurea species could be an anticholinesterase agent and antioxidant resource in some industries, such as food, pharmacology, and cosmetics.

Physicochemical comparison of chitin and chitosan obtained from larvae and adult Colorado potato beetle (Leptinotarsa decemlineata)

Chitins and chitosans obtained from larva and adult Colorado potato beetles (Leptinotarsa decemlineata) were physico-chemically characterized and differences between adults and larvae were identified. The dry weight chitin contents of the adult Colorado potato beetles and larvae were determined as 20% and 7%, respectively. The chitin produced chitosan yields of 72% from the adult Colorado potato beetles and 67% from the larvae. FTIR analysis showed that the isolated chitins were in the alpha form. Crystalline index values, determined by XRD, were 72% for larvae and 76% for adults. The degradation temperatures of the isolated chitin structures were measured by TGA, and this showed that the chitin from adult Colorado potato beetles had a more stable structure than that from the larvae. The surface morphologies of the isolated chitin and chitosan structures were analysed with SEM and it was revealed that these structures consisted of nanofibres. According to elemental analysis, the purity of chitin and chitosan from adults was greater than that from the larvae. The results of molecular analysis showed that the chitosans from adults (2.722 kDa) and larvae (2.676 kDa) of the Colorado potato beetle have low molecular weights. Antimicrobial and antioxidant activities of both adult and larval chitosans were determined. The adult potato beetle is more appropriate than the larvae as an alternative chitin source because of the fact that its dry weight chitin content, chitosan yield and purity of chitin are higher than those from the larvae, and its antimicrobial and antioxidant activities are also higher than those from the larvae.

New Chitin, Chitosan, and O-Carboxymethyl Chitosan Sources from Resting Eggs of Daphnia longispina (Crustacea); with Physicochemical Characterization, and Antimicrobial and Antioxidant Activities

The paper describes the isolation and characterization of chitin and chitosan from Daphnia longispina resting eggs harvested from a reservoir. Resting eggs are fertilized eggs that are encased in chitinous shells called ‘ephippia’ and which ensure the survival of the Daphnia population in adverse conditions. The chitin-content of D. longispina resting eggs was found to be 23 ∼ 25% and the chitosan (having a 70 ∼ 75% deacetylation degree) yield of the chitin was 76 ∼ 77%. This high chitin-content indicates that D. longispina resting eggs can be exploited as a chitin source. The structure and thermal properties of chitin, extracted from D. longispina resting eggs, were characterized by employing Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffraction and scanning electron microscopy. The crystallinity of the chitin was found to be very low (48%). Physicochemicallycharacterized chitosan and the produced O-carboxymethyl chitosan were tested for their antimicrobial and antioxidant activity. It has been observed that chitosan displays antimicrobial activity against all pathogenic bacteria, whereas O-carboxymethyl chitosan only exhibits inhibition activity against L. garvieae, L. Monocytogenes ATCC 7644, Y. enterocolitica NCTC 11175 and S. aureus ATCC 25923. In a free radical scavenging activity assay, the IC50 values of chitosan, O-carboxymethyl chitosan and butylated hydroxytoluene were found to be 23.01, 56.43 and 0.05, respectively. The ferric-reducing power of O-carboxymethyl chitosan (EC50 = 8.30) indicated higher activity than chitosan (EC50 = 10.12).

Physicochemical Characterization of Chitin and Chitosan Obtained from Resting Eggs of Ceriodaphnia Quadrangula (Branchiopoda: Cladocera: Daphniidae)

Chitin and chitosan were produced from the structures of the resting eggs of Ceriodaphnia quadrangula (Muller, 1785), of which tons are naturally produced in a dammed lake. On a dry weight basis, 16-17% chitin and 11% chitosan were extracted from the resting egg structures. The degree of deacetylation of the extracted chitosan was determined to be 80%. The produced chitin and chitosan materials were characterized using FT-IR, TGA, XRD and SEM. The crystalline index value of the chitin was measured as 74%. DTGmax values of chitin and chitosan were determined to be 381°C and 300°C, respectively. Based on a review of surface morphology, it was observed that both chitin and chitosan consist of nanofibre structures. We take the advantage of the excessive resting eggs production in adverse condition in the lake to produce an economically feasible source of chitin and chitosan. We conclude that α-chitin and chitosan produced from resting eggs of C. quadrangula can be used as an alternative source of these materials.

Diatomite as a novel composite ingredient for chitosan film with enhanced physicochemical properties

Practical applications of biopolymers in different industries are gaining considerable increase day by day. But still, these biopolymers lack important properties in order to meet the industrial demands. In the same regard, in the current study, chitosan composite films are produced by incorporating diatomite soil at two different concentrations. In order to obtain a homogeneous film, glutaraldehyde was supplemented to chitosan solution as a cross-linker. Compositing diatomaceous earth to chitosan film resulted in improvement of various important physicochemical properties compared to control such as; enhanced film wettability, increase elongation at break and improved thermal stability (264-277°C). The microstructure of the film was observed to haveconsisted of homogeneously distributed blister-shaped structures arised due to the incorporation of diatomite. The incorporation of diatomite did not influence the overall antioxidant activity of the composite films, which can be ascribe to the difficulty radicals formation. Chitosan film incorporated with increasing fraction of diatomite revealed a notable enhancement in the antimicrobial activity. Additionally with the present study, for the first time possible interactions between chitosan/diatomite were determined via quantum chemical calculations. Current study will be helpful in giving a new biotechnological perspective to diatom in terms of its successful application in hydrophobic composite film production.

Effect of different animal fat and plant oil additives on physicochemical, mechanical, antimicrobial and antioxidant properties of chitosan films

Practical application of chitosan-essential oil blend films is limited due to the uneconomical extraction procedure of essential oils from plants. This study aimed to produce chitosan films blended with low cost and commercially available oils and fats consumed in daily human diet (olive, corn and sunflower oils, butter and animal fats). The study also focused on how physicochemical, biological and mechanical properties of chitosan blend films were influenced by the incorporation of oils and fats with varying unsaturation degrees. Possible interactions of chitosan film matrix with incorporated oils or fats were investigated. Chitosan-olive oil film showed better surface morphology and higher thermal stability than the films with other unsaturated oils. Tensile strength, Youngs modulus and elongation at break were improved by 57.2%, 25.1% and 31.7% for chitosan-olive oil film, respectively. Chitosan-olive oil blend film had the highest antibacterial activity (almost equal to that of commercial antibiotic gentamicin). Edible films obtained from by incorporation of natural oils and fats into chitosan can help produce an environmentally friendly packaging material that is low cost and easily manufactured.

Fatty acid composition of five Algerian bisexual and parthenogenetic strains of Artemia (Anostraca, Crustacea) and their antimicrobial activity

The brine shrimp Artemia remains among the most important food used in fish and crustacean larviculture, and the study of its cysts’ nutritional quality is of great importance for products selection. Fatty acids (FAs) from decapsulated cysts of two bisexual (A. salina) and three parthenogenetic strains (A. parthenogenetica) from Algeria have been analyzed by gas chromatography. The aim was, first, to check the suitability of these strains as food for aquaculture and, second, to evaluate the FAs’ efficiency in inhibition of some of the fish pathogen’s activities. Percentages of total lipids were between 7.78 and 24.55% for the parthenogenetic strains of Bethioua and Sidi Bouziane salterns, respectively. Twenty-three FAs have been detected, and a high value of eicosapentaenoic (EPA; 20:5n-3) was observed in the parthenogenetic strain of Sidi Bouziane with 16.25xa0±xa00.08% (39.89xa0mgxa0g−1 dry weight). The highest value of α-linolenic (ALA; 18:3n-3) was observed in A. salina from Chott Marouane with 22.28xa0±xa00.16%, (30.72xa0mgxa0g−1 dry weight). The results of the antimicrobial screening assay of FA extracts showed their inhibitory activity against six fish pathogens. In comparison with ampicillin (Amp) and kanamycin antibiotics, all the studied strains of Artemia, except Bethioua, had better antimicrobial effect of their FAs against Vibrio anguillarum (gram-negative) than Amp. Streptococcus agalactiae (gram-positive) was the most resistant against Artemia’s FAs. Decapsulated cysts with the highest proportions of PUFAs and rich in ALA and linoleic were the most effective against the bacterial growth. Regarding the FAs’ composition and their antibacterial properties, Algerian strains of Artemia are good candidates for use as food in larviculture.

Antioxidative and antimicrobial edible chitosan films blended with stem, leaf and seed extracts of Pistacia terebinthus for active food packaging

Methanol extracts of stem, leaf, and seed obtained from Pistacia terebinthus which are rich in phenolic compounds were used for the first time to produce chitosan-based antioxidative and antimicrobial films. All the produced films were characterized by FT-IR, TGA, DSC, SEM, contact angle measurements, and UV-Vis spectroscopy and mechanically. As was expected, incorporation of the plant extracts into chitosan films enhanced the antioxidant and antimicrobial activities effectively. Also, the elasticity of chitosan-seed and chitosan-stem films was improved. The eco-friendly nature of the produced blend films was determined through soil and water degradation analyses. All these findings lead to the conclusion that the produced blend films with Pistacia terebinthus extracts can be applied as alternative food packaging material.

False flax ( Camelina sativa ) seed oil as suitable ingredient for the enhancement of physicochemical and biological properties of chitosan films

To overcome the drawbacks of synthetic films in food packaging industry, researchers are turned to natural bio-based edible films enriched with various plant additives. In current study chitosan blend films were produced by incorporating Camelina sativa seed oil at varying concentrations to chitosan matrix. The chitosan blend films were characterized both physicochemically (structural, morphological, thermal, optical and mechanical) and biologically (antimicrobial and antioxidant activity). The incorporation of C. sativa seed oil notably enhanced thermal stability, antioxidative, anti-quorum sensing and antimicrobial activity. Except elongation at break, other mechanical properties of the blend films were not affected by incorporation of C. sativa seed oil. The surface morphology of blend films was recorded as slightly rough, non-porous and fibre-free surface. As it was expected the optical transmittance in visible region was gradually decreased with increasing fraction of seed oil. Interestingly the hydrophilicity of the blend films revealed a swift increase which can be explained by the formation of micelle between glycerol and Tween 40 in blend films. This study provides valuable information for C. sativa seed oil to be used as a blending ingredient in chitosan film technology.

Supplementing capsaicin with chitosan-based films enhanced the anti-quorum sensing, antimicrobial, antioxidant, transparency, elasticity and hydrophobicity

In the current study, capsaicin, a plant alkaloid with high antioxidative, anti-inflammatory, antiobesity, anticancer and analgesic properties, was used in the film technology for the first time. In the same regard, chitosan (as a versatile animal-based polymer) was blended with capsaicin at three different concentrations to obtain edible films. The produced films were characterized by FT-IR, SEM, and DSC. Mechanical, transmittance, hydrophobicity, anti-quorum sensing, antimicrobial and antioxidant properties were also examined. Incorporation of 0.6u202fmg of capsaicin into the chitosan matrix (200u202fmg dissolved in 1% acetic acid solution) was observed as an optimal concentration for boosting up three film properties including mechanical, optical and surface morphology. A continuous improvement was recorded in anti-quorum sensing and antimicrobial activities, antioxidative and hydrophobicity with increasing concentration of capsaicin in the film. In further studies, chitosan-capsaicin blend films can be used as a food packaging material as well dermal and wound healing patches.