Changes in composition and content of phenolic compounds in leaves of red grapevine varieties during certain phenophases

Fenolni spojevi predstavljaju sekundarne biljne metabolite koji imaju vrlo važnu fiziološku i morfološku ulogu u rastu i reprodukciji biljke te joj pružaju zaštitu protiv patogena i predatora. Brojni su istraživači ukazali na blagodati fenolnih spojeva na temelju čega je prepoznata njihova važnost u zaštiti biljke od abiotičkih i biotičkih stresova, te u antikancerogenom, antialergijskom, protuupalnom, antimikrobnom i neuroprotektivnom djelovanju. Ujedno, zbog svoga djelovanja koji utječe pozitivno na ljudsko zdravlje, fenolni spojevi su korišteni u farmaceutskoj, prehrambenoj i kozmetičkoj industriji. Samim time, glavni cilj ovoga istraživanja je dobiti pregled i bolje shvaćanje promjena u sastavu i sadržaju fenolnih spojeva, točnije flavonola, flavan-3-ola, hidroksicimetnih i hidroksibenzojevih kiselina prisutnih u listovima 12 različitih sorata vinove loze. Istraživanje se odvijalo na vinogradarsko vinarskom pokušalištu „Jazbina“ tijekom 2018. godine. Uzorci su sakupljani periodično, počevši sa završetkom cvatnje vinove loze do tehnološke zrelosti pojedinih sorata, točnije od 22.06. do 13.09. Listovi su potom adekvatno pohranjeni, podvrgnuti procesima liofilizacije i ekstrakcije. Ekstrakti su analizirani tekućinskom kromatografijom visoke djelotvornosti. Dobiveni rezultati su obrađeni pomoću jednosmjerne analize varijance i Duncan Multiple Range testa. Temeljem dobivenih rezultata utvrđena je značajna varijabilnost u masenim udjelima fenolnih spojeva između sorata po pojedinim terminima uzorkovanja, kao i značajna varijabilnost u sadržaju fenolnih spojeva unutar iste sorte tijekom različitih termina uzorkovanja.Phenolic compounds represent secondary plant metabolites which play an important physiological and morphological role in plant growth and reproduction. They also provide a protection against pathogens and predators. Numerous researches have pointed to the benefits of phenolic compounds, which served as a basis for the recognition of their importance. They protect the plant from abiotic and biotic stress and contain anticancer, anti-allergic, anti-inflammatory, antimicrobial and neuroprotective positive properties. Moreover, because of their composition which positively affects human health, phenolic compounds are used in pharmaceutical, food and cosmetic industry. Therefore, the main aim of this research is to gain a review and a better understanding of the changes in the composition and the content of the following phenolic compounds: flavonoid, flavan-3-ol, hydroxycyclic acid and hydroxybenzoic acid present in the leaves of twelve different grapevine varieties. The research was conducted in the Jazbina Experimental Station during 2018. The samples were periodically collected, starting with the end of the flowering of the grapevine up to tehnological maturity of individual grapevine varieties . The research was conducted in the period from 6/22 to 9/13 to be exact. The leaves were then adequately stored and subjected to processes of lifolysis and extraction. The extracts were analyzed by high-performance liquid chromatography. The results were processed with the help of one-way analysis of variance and Duncan Multiple Range test. Based on the obtained dana, a significant variability in the mass shares of phenolic compunds between different grapevine varieties during individual sampling periods was found. Moreover, a significant variability in the content of phenolic compunds within the same grapevine variety during different sampling periods was found as well