Phenolic composition and antioxidant properties in different organs of Hypericum elongatum and Hypericum orientale

Öz

This study investigates the phytochemical composition and antioxidant capacity of two underexplored Hypericum species, H. elongatum and H. orientale. Methanolic extracts of flowers, leaves, and stems were evaluated for total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity using DPPH, FRAP, and CUPRAC assays. 24 phenolic compounds were quantified by high-performance liquid chromatography with diode-array detection (HPLC-DAD). The TPC values ranged from 7.6 to 37.9 mg GAE/g, and TFC values from 1.9 to 10.7 mg QE/g. H. orientale generally showed higher phenolic and flavonoid levels, with its flower extract exhibiting the highest TPC (37.87 ± 1.86 mg GAE/g) and TFC (10.66 ± 0.30 mg QE/g). All extracts demonstrated notable antioxidant activity. Remarkably, the H. elongatum leaf extract had a very low DPPH IC₅₀ value (0.02 mg/mL), indicating strong radical-scavenging capacity. Its leaf also showed the highest FRAP value (299.38 ± 13.99 µmol FeSO₄·7H₂O/g) among all samples. The dominant phenolics in both species were catechin and epicatechin; kaempferol was detected only in H. orientale flowers (75.91 mg/kg). Hypericin was present in all tissues, with the highest concentration in H. orientale leaves (27.5 mg/kg). These findings highlight the significant antioxidant potential of both species, particularly in their flowers and leaves and suggest they may serve as valuable sources of natural antioxidants in phytomedicine.

Anahtar Kelimeler

• Hypericum
• Hypericin
• Antioxidant
• HPLC
• Phenolic

Hypericum elongatum ve Hypericum orientale türlerinin farklı bitki kısımlarında fenolik içerik ve antioksidan kapasitenin karşılaştırmalı olarak incelenmesi

Öz

Bu çalışma, az incelenmiş iki Hypericum türü olan H. elongatum ve H. orientale’nin fitokimyasal bileşimini ve antioksidan kapasitesini araştırmaktadır. Çiçek, yaprak ve gövde kısımlarından elde edilen metanol ekstreleri; toplam fenolik içeriği (TPC), toplam flavonoid içeriği (TFC) ve DPPH, FRAP ve CUPRAC yöntemleri kullanılarak antioksidan aktivite açısından değerlendirilmiştir. Ayrıca, yüksek performanslı sıvı kromatografisi-diyot dizisi dedektörü (HPLC-DAD) kullanılarak 24 fenolik bileşik nicel olarak belirlenmiştir. TPC değerleri 7.6–37.9 mg GAE/g, TFC değerleri ise 1.9–10.7 mg QE/g aralığında bulunmuştur. H. orientale genel olarak daha yüksek fenolik ve flavonoid içerikleri göstermiş; özellikle çiçek ekstresi en yüksek TPC (37.87 ± 1.86 mg GAE/g) ve TFC (10.66 ± 0.30 mg QE/g) değerlerini vermiştir. Tüm ekstreler belirgin antioksidan aktivite göstermiştir. Dikkat çekici olarak, H. elongatum yaprak ekstresinin DPPH IC₅₀ değeri oldukça düşük bulunmuştur (0.02 mg/mL); bu durum güçlü serbest radikal süpürme kapasitesine işaret etmektedir. Aynı organsal kısım ayrıca tüm örnekler içinde en yüksek FRAP değerini göstermiştir (299.38 ± 13.99 µmol FeSO₄·7H₂O/g). Her iki türde de baskın fenolik bileşiklerin kateşin ve epikateşin olduğu belirlenmiştir; kaempferol ise yalnızca H. orientale çiçeklerinde tespit edilmiştir (75.91 mg/kg). Hiperisin tüm dokularda saptanmış olup, en yüksek konsantrasyon H. orientale yapraklarında gözlenmiştir (27.5 mg/kg). Bu bulgular, her iki türün özellikle çiçek ve yaprak kısımlarında belirgin antioksidan potansiyel taşıdığını ortaya koymakta ve bu türlerin fitoterapötik uygulamalarda doğal antioksidan kaynağı olarak değerlendirilebileceğini göstermektedir.

Anahtar Kelimeler

• Hypericum
• Hiperisin
• Antioksidan
• HPLC
• Fenolik

Kaynakça

1. V. Butterweck, V. Christoffel, A. Nahrstedt, F. Petereit, B. Spengler, H. Winterhoff, Step by step removal of hyperforin and hypericin: activity profile of different Hypericum preparations in behavioral models, Life Sci, 73, 2003, 627-639.
2. E.E. Özkan, A. Mat, An overview on Hypericum species of Turkey, J Pharmacogn Phytother, 5, 2013, 38-46.
3. C. Cirak, J. Radusiene, V. Jakstas, L. Ivanauskas, F. Yayla, F. Seyis, N. Camas, Secondary metabolites of Hypericum species from the Drosanthe and Olympia sections, S Afr J Bot, 104, 2016, 82-90.
4. S.L. Crockett, Essential oil and volatile components of the genus Hypericum (Hypericaceae), Nat Prod Commun, 5, 2010, 1934578X1000500926.
5. A.I. Oliveira, C. Pinho, B. Sarmento, A.C. Dias, Neuroprotective activity of Hypericum perforatum and its major components, Front Plant Sci, 7, 2016, 1004.
6. C. Cirak, F. Seyis, Phenolic constituents of six Hypericum species from Türkiye and their chemotaxonomic relevance, S Afr J Bot, 159, 2023, 596-604.
7. Y. Ghasemi, A. Khalaj, A. Mohagheghzadeh, A.R. Khosravi, M.H. Morowvat, Composition and antimicrobial activity of the essential oil and extract of Hypericum elongatum, J Appl Sci, 7, 2007, 2671-2675.
8. M.E. Grafakou, C. Barda, G.A. Karikas, H. Skaltsa, Hypericum essential oils—composition and bioactivities: an update (2012–2022), Molecules, 27, 2022, 5246.

9. S. Sarıkaya-Aydın, V.M. Kutluay, T. Makino, M. Inoue, Ü.Ş. Harput, İ. Saraçoğlu, Isolation of potential liver x receptor alpha agonist and antioxidant compounds from Hypericum microcalycinum Boiss. & Heldr., Istanbul J Pharm, 51, 2020, 98-104.
10. J. Zhang, L. Gao, J. Hu, C. Wang, P.L. Hagedoorn, N. Li, X. Zhou, Hypericin: source, determination, separation, and properties, Sep Purif Rev, 51, 2022, 1-10.
11. A.P. Guedes, G. Franklin, M. Fernandes-Ferreira, Hypericum sp.: essential oil composition and biological activities, Phytochem Rev, 11, 2012, 127-152.
12. G.M. Kitanov, Hypericin and pseudohypericin in some Hypericum species, Biochem Syst Ecol, 29, 2001, 171-178.
13. C. Çırak, J. Radušiene, V. Janulis, L. Ivanauskas, Chemical constituents of some Hypericum species growing in Turkey, J Plant Biol, 50, 2007, 632-635.
14. C. Cirak, J. Radusiene, Z. Stanius, N. Camas, O. Caliskan, M.S. Odabas, Secondary metabolites of Hypericum orientale L. growing in Turkey: variation among populations and plant parts, Acta Physiol Plant, 34, 2012, 1313-1320.
15. E. Altundag, M. Ozturk, Ethnomedicinal studies on the plant resources of East Anatolia, Turkey, Procedia Soc Behav Sci, 19, 2011, 756-777.
16. Ş. Kültür, B. Gürdal, A. Sari, G. Melikoğlu, Traditional herbal remedies used in kidney diseases in Turkey: an overview, Turk J Bot, 45, 2021, 269-287.
17. N.K.B. Robson, Hypericum L, Flora of Turkey and the East Aegean Islands (Vol 2), Editor: P.H. Davis, 1967, Edinburgh, Edinburgh University Press.
18. T. Ekim, Hypericum L, Türkiye Bitkileri Listesi; Damarlı Bitkiler, Editor: T. Ekim, 2012, Ankara, Türkiye Bilimler Akademisi Yayınları.
19. A. Uysal, G. Zengin, Y. Durak, A. Aktumsek, Screening for antioxidant and antimutagenic properties of extracts from Centaurea pterocaula as well as theirs enzyme inhibitory potentials, Marmara Pharm J, 20, 2016, 232-242.
20. İ. Akbulut, E. Gürbüz, A. Rayman Ergün, T. Baysal, Drying of apricots treated with Ginkgo biloba plant extract and determination of the quality properties, J Adv Res Nat Appl Sci, 7, 2021, 145-159.
21. V.L. Singleton, R. Orthofer, R.M. Lamuela-Raventós, Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin-Ciocalteu reagent, Methods in Enzymology, Editor: L. Packer, 2019, San Diego, Academic Press.
22. J. Zhishen, T. Mengcheng, W. Jianming, The determination of flavonoid contents in mulberry and their scavenging effects on superoxide radicals, Food Chem, 64, 1999, 555-559.
23. P. Molyneux, The use of the stable free radical diphenylpicrylhydrazyl (DPPH) for estimating antioxidant activity, Songklanakarin J Sci Technol, 26, 2004, 211-219.
24. R.E. Mutha, A.U. Tatiya, S.J. Surana, Flavonoids as natural phenolic compounds and their role in therapeutics: an overview, Future J Pharm Sci, 7, 2021, 25.
25. I.F. Benzie, Y.T. Szeto, Total antioxidant capacity of teas by the ferric reducing/antioxidant power assay, J Agric Food Chem, 47, 1999, 633-636.
26. M. Özyürek, K. Güçlü, E. Tütem, K.S. Başkan, E. Erçağ, S. Esin Çelik, S. Baki, L. Yıldız, Ş. Karaman, R. Apak, Comprehensive review of CUPRAC methodology, Anal Methods, 3, 2011, 2439-2453.
27. T. Seal, Quantitative HPLC analysis of phenolic acids, flavonoids and ascorbic acid in four different solvent extracts of Sonchus arvensis and Oenanthe linearis, J Appl Pharm Sci, 6, 2016, 157-166.
28. Y. Alan, Chemical changes of potential probiotic Lactiplantibacillus plantarum and Lactobacillus pentosus starter cultures in natural Gemlik type black olive fermentation, Food Chem, 434, 2023, 137472.
29. G. Agati, E. Azzarello, S. Pollastri, M. Tattini, Flavonoids as antioxidants in plants: location and functional significance, Plant Sci, 196, 2012, 67-76.
30. B. Winkel-Shirley, Flavonoid biosynthesis: a colorful model for genetics, biochemistry, cell biology, and biotechnology, Plant Physiol, 126, 2001, 485-490.
31. A. Smelcerovic, V. Verma, M. Spiteller, S.M. Ahmad, S.C. Puri, G.N. Qazi, Phytochemical analysis and genetic characterization of six Hypericum species from Serbia, Phytochemistry, 67, 2006, 171-177.
32. C. Çırak, J. Radušienė, V. Janulis, L. Ivanauskas, Secondary metabolites in Hypericum perfoliatum: variation among plant parts and phenological stages, Bot Helv, 117, 2007, 29-36.
33. J. Dai, R.J. Mumper, Plant phenolics: extraction, analysis and their antioxidant and anticancer properties, Molecules, 15, 2010, 7313-7352.
34. M.A.K. Jansen, V. Gaba, B.M. Greenberg, Higher plants and UV-B radiation: balancing damage, repair and acclimation, Trends Plant Sci, 3, 1998, 131-135.
35. A.N. Panche, A.D. Diwan, S.R. Chandra, Flavonoids: an overview, J Nutr Sci, 5, 2016, e47.
36. World Health Organization, WHO guidelines on good agricultural and collection practices (GACP) for medicinal plants, 2003, Geneva, WHO Press.
37. R.L. Prior, X. Wu, K. Schaich, Standardized methods for the determination of antioxidant capacity and phenolics in foods and dietary supplements, J Agric Food Chem, 53, 2005, 4290-4302.
38. C.A. Rice-Evans, N.J. Miller, G. Paganga, Structure-antioxidant activity relationships of flavonoids and phenolic acids, Free Radic Biol Med, 20, 1996, 933-938.
39. A. Cakir, A. Mavi, A. Yildirim, M.E. Duru, M. Harmandar, C. Kazaz, Isolation and characterization of antioxidant phenolic compounds from the aerial parts of Hypericum hyssopifolium L. by activity-guided fractionation, J Ethnopharmacol, 87, 2003, 73-83.
40. A. Matkowski, P. Tasarz, E. Szypuła, Antioxidant activity of herb extracts from five medicinal plants from Lamiaceae, subfamily Lamioideae, J Med Plants Res, 2, 2008, 321-330.
41. L.P. Köse, İ. Gülçin, A.C. Gören, J. Namiesnik, A.L. Martinez-Ayala, S. Gorinstein, LC-MS/MS analysis, antioxidant and anticholinergic properties of galanga (Alpinia officinarum Hance) rhizomes, Ind Crops Prod, 74, 2016, 712-721.
42. F. Conforti, G.A. Statti, R. Tundis, F. Menichini, P. Houghton, Antioxidant activity of methanolic extract of Hypericum triquetrifolium Turra aerial part, Fitoterapia, 73, 2002, 479-483.
43. S. Sapkota, A. Maharjan, S. Tiwari, M. Rajbhandari, Phytochemical analysis, antioxidant potential and antibacterial activities of different anatomical parts of Hypericum cordifolium Choisy, Sci World J, 2024, 8128813.
44. K. Khanbabaee, T. van Ree, Tannins: classification and definition, Nat Prod Rep, 18, 2001, 641-649.
45. R.V. Barbehenn, C.P. Constabel, Tannins in plant-herbivore interactions, Phytochemistry, 72, 2011, 1551-1565.
46. B. Kaczmarek, Tannic acid with antiviral and antibacterial activity as a promising component of biomaterials—a minireview, Materials, 13, 2020, 3224.
47. A. Nahrstedt, V. Butterweck, Biologically active and other chemical constituents of the herb of Hypericum perforatum L, Pharmacopsychiatry, 30, 1997, 129-134.
48. K.E. Heim, A.R. Tagliaferro, D.J. Bobilya, Flavonoid antioxidants: chemistry, metabolism and structure-activity relationships, J Nutr Biochem, 13, 2002, 572-584.
49. İ. Gülçin, Antioxidant activity of food constituents: an overview, Arch Toxicol, 86, 2012, 345-391.
50. M. Leopoldini, N. Russo, M. Toscano, The molecular basis of working mechanism of natural polyphenolic antioxidants, Food Chem, 125, 2011, 288-306.
51. D. Huang, B. Ou, R.L. Prior, The chemistry behind antioxidant capacity assays, J Agric Food Chem, 53, 2005, 1841-1856.
52. C. Ullah, S.B. Unsicker, C. Fellenberg, C.P. Constabel, A. Schmidt, J. Gershenzon, A. Hammerbacher, Flavan-3-ols are an effective chemical defense against rust infection, Plant Physiol, 175, 2017, 1560-1578.
53. N. Smirnoff, Ascorbic acid: metabolism and functions of a multi-facetted molecule, Curr Opin Plant Biol, 3, 2000, 229-235.