Osman Tuncay Ağar

Dr. Osman Tuncay Ağar

Department of Agriculture and Food Systems, University of Melbourne, Melbourne, Victoria, Australia
orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

View All Publications
31 May 2021 in Cancers
Verified
Journal Article
Open access
PDF file
Esra KÜPELİEsra KÜPELİ
Esra KÜPELİ
ITIffet Irem Tatli
Iffet Irem Tatli
GKGökçe Şeker Karatoprak
Gökçe Şeker Karatoprak
OAOsman Tuncay Ağar
Osman Tuncay Ağar
ÇYÇiğdem Yücel
Çiğdem Yücel
Raffaele CapassoRaffaele Capasso
Raffaele Capasso
Many anticancer active compounds are known to have the capacity to destroy pathologically proliferating cancer cells in the body, as well as to destroy rapidly proliferating normal cells. Despite remarkable advances in cancer research over the past few decades, the inclusion of natural compounds in researches as potential drug candidates is becoming increasingly important. However, the perception that the natural is reliable is an issue that needs to be clarified. Among the various chemical classes of natural products, anthraquinones have many biological activities and have also been proven to exhibit a unique anticancer activity. Emodin, an anthraquinone derivative, is a natural compound found in the roots and rhizomes of many plants. The anticancer property of emodin, a broad-spectrum inhibitory agent of cancer cells, has been detailed in many biological pathways. In cancer cells, these molecular mechanisms consist of suppressing cell growth and proliferation through the attenuation of oncogenic growth signaling, such as protein kinase B (AKT), mitogen-activated protein kinase (MAPK), HER-2 tyrosine kinase, Wnt/-catenin, and phosphatidylinositol 3-kinase (PI3K). However, it is known that emodin, which shows toxicity to cancer cells, may cause kidney toxicity, hepatotoxicity, and reproductive toxicity especially at high doses and long-term use. At the same time, studies of emodin, which has poor oral bioavailability, to transform this disadvantage into an advantage with nano-carrier systems reveal that natural compounds are not always directly usable compounds. Consequently, this review aimed to shed light on the anti-proliferative and anti-carcinogenic properties of emodin, as well as its potential toxicities and the advantages of drug delivery systems on bioavailability.

30 September 2015 in Molecules
Verified
Journal Article
Open access
PDF file
OAOsman Tuncay Ağar
Osman Tuncay Ağar
MDMiriş Dikmen
Miriş Dikmen
NONilgun Ozturk
Nilgun Ozturk
Mustafa Abdullah YILMAZMustafa Abdullah YILMAZ
Mustafa Abdullah YILMAZ
Hamdi TemelHamdi Temel
Hamdi Temel
FTFatma Pinar Turkmenoglu
Fatma Pinar Turkmenoglu
Turkey is one of the most important centers of diversity for the genus Achillea L. in the world. Keeping in mind the immense medicinal importance of phenols, in this study, three species growing in Turkey, A. coarctata Poir. (AC), A. kotschyi Boiss. subsp. kotschyi (AK) and A. lycaonica Boiss. & Heldr. (AL) were evaluated for their phenolic compositions, total phenolic contents (TPC), antioxidant properties, wound healing potencies on NIH-3T3 fibroblasts and cytotoxic effects on MCF-7 human breast cancer cells. Comprehensive LC-MS/MS analysis revealed that AK was distinctively rich in chlorogenic acid, hyperoside, apigenin, hesperidin, rutin, kaempferol and luteolin (2890.6, 987.3, 797.0, 422.5, 188.1, 159.4 and 121.2 µg analyte/g extract, respectively). The findings exhibited a strong correlation between TPC and both free radical scavenging activity and total antioxidant capacity (TAC). Among studied species, the highest TPC (148.00 mg GAE/g extract) and TAC (2.080 UAE), the strongest radical scavenging (EC50 = 32.63 μg/mL), the most prominent wound healing and most abundant cytotoxic activities were observed with AK. The results suggested that AK is a valuable source of flavonoids and chlorogenic acid with important antioxidant, wound healing and cytotoxic activities. These findings warrant further studies to assess the potential of AK as a bioactive source that could be exploited in pharmaceutical, cosmetics and food industries.

2 April 2023 in Food Reviews International
Verified
Journal Article
Open access
YZYing Zhou
Ying Zhou
MCMinghang Chu
Minghang Chu
FAFarhad Ahmadi
Farhad Ahmadi
OAOsman Tuncay Ağar
Osman Tuncay Ağar
CBColin J. Barrow
Colin J. Barrow
Hafiz SuleriaHafiz Suleria
Hafiz Suleria
Mushrooms have been an acclaimed food for their unique flavor and medicinal properties since ancient times. Modern research shows that mushrooms are rich in various nutrients and biologically active substances. In recent years, researchers have become increasingly interested in mushrooms because they contain important secondary metabolites, such as phenolic compounds with significant bioactive properties. This review introduces the nutritional components and secondary metabolites in mushrooms, focusing on the bioactive functions and potential applications of mushroom polyphenols. Finally, the current challenges and future research trends of mushroom polyphenols are briefly discussed. In the aspect of nutritional value, mushrooms are high in protein and insoluble fiber, while low in fat and sodium, making them a low-energy, healthy food. Mushrooms contain a large amount of beneficial bioactive substances for health, including phenolic compounds, as well as tocopherols, terpenoids, and phytosterols. Mushroom polyphenols have antioxidant, anti-inflammatory, anti-cancer, anti-tyrosine, antihyperglycemic, and other biological activities beneficial to human health and medical applications, especially in the various degenerative disease and cancer treatments. However, based on the properties of phenolic compounds, research and development in commercial applications still face many issues that need to be addressed by researchers.

12 January 2023 in Antioxidants
Verified
Journal Article
Open access
PDF file
XLXiaoyan Lyu
Xiaoyan Lyu
OAOsman Tuncay Ağar
Osman Tuncay Ağar
CBColin Barrow
Colin Barrow
Frank R. DunsheaFrank R. Dunshea
Frank R. Dunshea
Hafiz SuleriaHafiz Suleria
Hafiz Suleria
Avocados (Persea americana M.) are highly valued fruits consumed worldwide, and there are numerous commercially available varieties on the market. However, the high demand for fruit also results in increased food waste. Thus, this study was conducted for comprehensive profiling of polyphenols of Hass, Reed, and Wurtz avocados obtained from the Australian local market. Ripe Hass peel recorded the highest TPC (77.85 mg GAE/g), TTC (148.98 mg CE/g), DPPH (71.03 mg AAE/g), FRAP (3.05 mg AAE/g), RPA (24.45 mg AAE/g), and ABTS (75.77 mg AAE/g) values; unripe Hass peel recorded the highest TFC (3.44 mg QE/g); and Wurtz peel recorded the highest TAC (35.02 mg AAE/g). Correlation analysis revealed that TPC and TTC were significantly correlated with the antioxidant capacity of the extracts. A total of 348 polyphenols were screened in the peel. A total of 134 compounds including 36 phenolic acids, 70 flavonoids, 11 lignans, 2 stilbenes, and another 15 polyphenols, were characterised through LC-ESI-QTOF-MS/MS, where the majority were from peels and seeds of samples extract. Overall, the hierarchical heat map revealed that there were a significant amount of polyphenols in peels and seeds. Epicatechin, kaempferol, and protocatechuic acid showed higher concentrations in Reed pulp. Wurtz peel contains a higher concentration of hydroxybenzoic acid. Our results showed that avocado wastes have a considerable amount of polyphenols, exhibiting antioxidant activities. Each sample has its unique value proposition based on its phenolic profile. This study may increase confidence in utilising by-products and encourage further investigation into avocado by-products as nutraceuticals.

22 June 2015 in Molecules
Verified
Journal Article
Open access
PDF file
FTFatma Pinar Turkmenoglu
Fatma Pinar Turkmenoglu
OAOsman Tuncay Ağar
Osman Tuncay Ağar
GAGalip Akaydin
Galip Akaydin
MHMutlu Hayran
Mutlu Hayran
BDBetul Demirci
Betul Demirci
According to distribution of genus Achillea, two main centers of diversity occur in S.E. Europe and S.W. Asia. Diversified essential oil compositions from Balkan Peninsula have been numerously reported. However, report on essential oils of Achillea species growing in Turkey, which is one of the main centers of diversity, is very limited. This paper represents the chemical compositions of the essential oils obtained by hydrodistillation from the aerial parts of eleven Achillea species, identified simultaneously by gas chromatography and gas chromatography-mass spectrometry. The main components were found to be 1,8-cineole, p-cymene, viridiflorol, nonacosane, α-bisabolol, caryophyllene oxide, α-bisabolon oxide A, β-eudesmol, 15-hexadecanolide and camphor. The chemical principal component analysis based on thirty compounds identified three species groups and a subgroup, where each group constituted a chemotype. This is the first report on the chemical composition of A. hamzaoglui essential oil; as well as the antioxidant and antimicrobial evaluation of its essential oil and methanolic extract.

15 May 2023 in Algal Research
Verified
Journal Article
Closed access
VSVigasini Subbiah
Vigasini Subbiah
XDXinyu Duan
Xinyu Duan
OAOsman Tuncay Ağar
Osman Tuncay Ağar
FDFrank R. Dunshea
Frank R. Dunshea
CBColin J. Barrow
Colin J. Barrow
HSHafiz A.R. Suleria
Hafiz A.R. Suleria