In vitro inhibitory effects of methanol extracts of four Centaurea species on α-amylase and α-glucosidase

Abstract

Aim: Medicinal plants have been used in traditional folk medicine for thousands of years against various diseases, including diabetes. Some Centaurea species are among these medicinal plants. The aim of this study was to scientifically and comparatively evaluate the antidiabetic activities of methanol extracts obtained from the capitulum and non-capitulum aerial parts of Centaurea cuneifolia, C. kilaea, C. solstitialis subsp. solstitialis and C. stenolepis against α-glucosidase and α-amylase for the first time except C. kilaea. Materials and Methods: Methanol extracts from Centaurea species were obtained by maceration method. Antidiabetic activity was performed by two known in vitro methods such as alpha-glucosidase and alpha amylase inhibitory activity. Results: Among the extracts, Centaurea cuneifolia capitula (CCC) and C. solstitialis subsp. solstitialis capitula (CSSC) methanol extracts with IC50 values of 164.30 and 463.70 μg/mL exhibited the best inhibitory activity against α-amylase and α-glucosidase enzymes. Conclusion: This is the first study on anti α-amylase and anti α-glucosidase activity of three Centaurea species except Centauera kilaea. These results indicate that CCC and CSSC have inhibitory effects against alpha amylase and alpha glucosidase. At the same time, the extracts were generally found to be active against the alpha amylase enzyme. In addition, it was found remarkable that only the capitulum of Centaurea species were effective against alpha glucosidase enzyme. However, in vivo studies are needed to fully reveal the antidiabetic effect and bioactivity-directed fractionation, and isolation studies are needed to reveal the compounds responsible for the antidiabetic effect.

Keywords

• Centaurea species
• diabetes
• antidiabetic activity
• α-glucosidase
• α-amylase

References

1. [1] Nguyen, N. H., Duong, T. H., Sichaem, J., Nguyen, T. D., Duong, G. H., Thi-Phuong, N., Ngoe, T-M-D., Tran, T-C-T., & Nguyen, H. T. (2025). Triterpenoids from leaves of Paramignya trimera with their alpha-glucosidase inhibition: In vitro and in silico aspects. Natural Product Research, 1-9.
2. [2] Christou, A., Stavrou, C., Michael, C., Botsaris, G., & Goulas, V. (2024). New insights into the potential inhibitory effects of native plants from Cyprus on pathogenic bacteria and diabetesrelated enzymes. Microbiology Research, 15(2), 926-942.
3. [3] Iqbal, T., Khan, S., Rahim, F., Hussain, R., Khan, Y., Felemban, S., & Khowdiary, M. M. (2024). Benzothiazole based sulfonamide scaffolds as active inhibitors of alpha-amylase and alpha-glucosidase; synthesis, structure confirmation, in silico molecular docking and ADME analysis. Journal of Molecular Structure, 1309, 138074.
4. [4] Ramos, J. A. V., Echeverry, M. S. V., Osma, J. A., & Chamarro, N. L. (2025). In vitro study on the α-glucosidase inhibitory activity and antioxidant capacity of leaf extracts of Coffea arabica (Caturra variety). Journal of Herbs, Spices & Medicinal Plants, 1-13.
5. [5] Bizim Bitkiler (2025). https://www.bizimbitkiler.org.tr/v2/hiyerarsi. php?c=Centaurea (Access date: 18.03.2025)
6. [6] Tuzlacı E. (2016). Türkiye Bitkileri Geleneksel İlaç Rehberi, İstanbul Kitabevleri, İstanbul (In Turkish)
7. [7] Dalar, A. (2018). Plant taxa used in the treatment of diabetes in Van province, Turkey. International Journal of Secondary Metabolite, 5(3), 171-185.
8. [8] Arif, R., Küpeli, E., & Ergun, F. (2004). The biological activity of Centaurea L. species. Gazi University Journal of Science, 17(4), 149-164.

9. [9] Şen, A. (2023). Antioxidant and anti-inflammatory activity of five Centaurea species. European Journal of Biology, 82(2), 311- 316.
10. [10] Şekerler, T., Şen, A., Bitiş, L., & Şener, A. (2020). In vitro antihepatocellular carcinoma activity of secondary metabolites of Centaurea kilaea Boiss. Journal of Research in Pharmacy, 24, 479-486.
11. [11] Sekerler, T., Sen, A., Bitis, L., & Sener, A. (2018). Anticancer, antioxidant and anti-inflammatory activities of chloroform extracts from some Centaurea species. Proceedings, 2(25), 1542.
12. [12] Şen, A., Bitiş, L., Birteksöz-Tan, S., & Bulut, G. (2013). In vitro evaluation of antioxidant and antimicrobial activities of some Centaurea L. species. Marmara Pharmaceutical Journal, 17(1), 42-45.
13. [13] Aksoy, H. (2020). Evaluation of the biological and wound healing activities of Centaurea virgata. Clinical and Experimental Health Sciences, 10(3), 304-308.
14. [14] Koca, U., Süntar, I. P., Keles, H., Yesilada, E., & Akkol, E. K. (2009). In vivo anti-inflammatory and wound healing activities of Centaurea iberica Trev. ex Spreng. Journal of Ethnopharmacology, 126(3), 551-556.
15. [15] Kısa, D., Imamoglu, R., Genc, N., Taslimi, P., Kaya, Z., & Taskin‐ Tok, T. (2023). HPLC analysis, phytochemical content, and biological effects of Centaurea kilaea against some metabolic enzymes: In vitro and in silico studies. ChemistrySelect, 8(6), e202204196.
16. [16] Zengin, G., Locatelli, M., Carradori, S., Mocan, A. M., & Aktumsek, A. (2016). Total phenolics, flavonoids, condensed tannins content of eight Centaurea species and their broad inhibitory activities against cholinesterase, tyrosinase, α-amylase and α-glucosidase. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 44(1), 195-200.
17. [17] Kısa, D., Çelik, A., & İmamoğlu, R. (2024). Assessment of inhibitory ability against medicinally important enzymes with in vitro and in silico studies: Phenolic content of endemic Centaurea cadmea subsp. pontica. Kahramanmaraş Sütçü İmam Üniversitesi Tarım ve Doğa Dergisi, 27(1), 14-25.
18. [18] Conforti, F., Menichini, F., Loizzo, M. R., Statti, A. G., Rapisarda, A., Menichini, F., & Houghton, P. J. (2008). Antioxidant, α-amylase inhibitory and brine-shrimp toxicity studies on Centaurea centaurium L. methanolic root extract. Natural Product Research, 22(16), 1457-1466.
19. [19] Yırtıcı, Ü., Ergene, A., Atalar, M. N., & Adem, Ş. (2022). Phytochemical composition, antioxidant, enzyme inhibition, antimicrobial effects, and molecular docking studies of Centaureasivasica. South African Journal of Botany, 144, 58-71.
20. [20] Dalar, A., Uzun, Y., Mukemre, M., Turker, M., & Konczak, I. (2015). Centaurea karduchorum Boiss. from Eastern Anatolia: Phenolic composition, antioxidant and enzyme inhibitory activities. Journal of Herbal Medicine, 5(4), 211-216.
21. [21] Nobarirezaeyeh, M., Yuca, H., Aydın, B., Civaş, A., Karakaya, S., Karadayı, M., Demir, A. Y., Bona, M., Yılmaz, B., Göger, G., Şahinöz, M.Z., Özer, E. B., Tekman, E., Güvenalp, Z. & Gençler Özkan, A. M. (2024). Phytochemical evaluation via GC-MS and LC-MS/MS: A comprehensive study of antidiabetic, antimicrobial, antioxidant, and genotoxic activities of extracts from endemic species Centaurea amanicola Hub.-Mor. and C. antitauri Hayek (Asteraceae). Natural Product Research, 1-10.
22. [22] Yıldırım, A., Şen, A., Göktaş, B., Uslu, H., Özakpınar, Ö. B., & Bitiş, L. (2024). Antiproliferative activity and molecular docking analyses of sesquiterpene lactones obtained from activity-directed isolation of Centaurea saligna (K. Koch) Wagenitz in neoplastic cells. Molecular Biotechnology, 1-13.
23. [23] Yıldırım, A., Şen, A., & Bitiş, L. (2024). Anti-inflammatory compounds and a new sesquiterpene lactone from Centaurea gabrieljanae Greuter. Natural Product Research, 1-11.
24. [24] Yıldırım, A., Şen, A., Göğer, F., Özakpınar, Ö. B., & Bitiş, L. (2022). In vitro antiproliferative, antioxidant, anti-inflammatory activities and phenolic profile of Centaurea saligna (K. Koch) Wagenitz. 26(1), 163-173.
25. [25] Sen, A., Kurkcuoglu, M., Yildirim, A., Senkardes, I., Bitis, L., & Baser, K. H. C. (2021). Chemical composition, antiradical, and enzyme inhibitory potential of essential oil obtained from aerial part of Centaurea pterocaula Trautv. Journal of Essential Oil Research, 33(1), 44-52.
26. [26] Sen, A., Ozbas Turan, S., & Bitis, L. (2017). Bioactivity-guided isolation of anti-proliferative compounds from endemic Centaurea kilaea. Pharmaceutical Biology, 55(1), 541-546.
27. [27] Polatoglu, K., Sen, A., Bulut, G., Bitis, L., & Gören, N. (2014). Essential oil composition of Centaurea stenolepis Kerner. from Turkey. Journal of Essential Oil Bearing Plants, 17(6), 1268- 1278.
28. [28] Sen, A., Gurbuz, B., Gurer, U. S., Bulut, G., & Bitis, L. (2014). Flavonoids and biological activities of Centaurea stenolepis. Chemistry of Natural Compounds, 50, 128-129.
29. [29] Polatoğlu, K., Şen, A., Bulut, G., Bitiş, L., & Gören, N. (2014). Essential oil composition of Centaurea kilaea Boiss. and C. cuneifolia Sm. from Turkey. Natural Volatiles & Essential Oils, 1(1), 55-59.
30. [30] Servi, H., Çelik, S., & Göktürk, R. S. (2019). Essential oil composition of two endemic Centaurea species from Turkey. Natural Volatiles and Essential Oils, 6(1), 18-24.
31. [31] Zengin, G., Cakmak, Y. S., Guler, G. O., & Aktumsek, A. (2010). In vitro antioxidant capacities and fatty acid compositions of three Centaurea species collected from Central Anatolia region of Turkey. Food and Chemical Toxicology, 48(10), 2638-2641.
32. [32] Ayad, R., & Akkal, S. (2019). Phytochemistry and biological activities of Algerian Centaurea and related genera. Studies in Natural Products Chemistry, 63, 357-414.
33. [33] Ramakrishna, R., Sarkar, D., Schwarz, P., & Shetty K. (2017). Phenolic linked anti-hyperglycemic bioactives of barley (Hordeum vulgare L.) cultivars as nutraceuticals targeting type 2 diabetes. Industrial Crops and Products, 107, 509-517.
34. [34] Sen, A., Kurkcuoglu, M., Senkardes, I., Bitis, L., Baser, K.H.C. (2019). Chemical composition, antidiabetic, anti-inflammatory and antioxidant activity of Inula ensifolia L. essential oil. Journal of Essential Oil Bearing Plants, 22(4), 1048-1057.