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Plants produce specialized metabolites, phenolics being one of them, in order to adapt to abiotic and biotic stresses more successfully. This study aimed to investigate which groups of phenolics in broccoli seedlings (Brassica oleracea botrytis var. cymosa) are more susceptible to concentration changes at high and low growing temperature. To answer this, in the fall of 2022/2023, we cultivated three biological replicas of broccoli seedlings in three different temperature conditions: high (38 °C day/33 °C night), low (12 °C day/7 °C night), and regular (23 °C day/18 °C night) as a control group. Seedlings were lyophilized, extracts in 70% ethanol prepared and spectrophotometric analyses of total phenolics, flavonoids, flavonols, hydroxycinnamic and phenolic acids were conducted. According to the results, total flavonols and flavonoids decreased significantly when seedlings were grown at both high and low temperatures, while total phenolics, phenolic and hydroxycinnamic acids decreased significantly only when grown at high temperature. Out of these groups of phenolics, total flavonols were the most susceptible to change when grown at high temperature, while total flavonoids were the most susceptible to change when grown at low temperature. Total phenolic acids were the most resistant at high and low temperature cultivation. In conclusion, high temperature cultivation significantly reduced the concentration of all analyzed groups of phenolics and had more impact on phenolics of broccoli seedlings than low temperature cultivation.

Plants challenged with high temperature (HT) undergo many adaptive mechanisms at molecular levels to keep normal physiological function. Such adaptations consequently influence their bioactivity. In this work, within the scope of the TEMPHYS project (IP-2020-02- 7585), we investigated the effect of HT on the antidiabetic activity of broccoli (Brassica oleracea L. convar. botrytis (L.) Alef. var. cymosa Duch.) seedlings. The activity was spectrophotometrically assessed via the percentage of inhibition of α-amylase and α-glucosidase, enzymes required for carbohydrate digestion. Enzyme inhibitory activity was calculated from the equation: % inhibition = 100 – [(At – Atb / Ac – Acb) x 100], where At was absorbance of test, Atb was absorbance of test blank, Ac was absorbance of control, and Acb was absorbance of control blank. Seedlings were grown in a climatic chamber with temperature range 23°C/16h, 18°C/8h for control group, and 38°C/16h, 33°C/8h for HT group. The extracts were prepared from freeze- dried plant material using boiling (100°C) water followed by incubation on rotary extractor for 1 hour at 23°C. The results showed that broccoli seedlings aqueous extracts were more efficient in the inhibition of α-amylase (88% relative to the standard acarbose), than α-glucosidase (67% relative to the standard acarbose). HT significantly (p≤0.05) decreased the potential to inhibit α-amylase (80%), however it improved the potential to inhibit α-glucosidase (70%). These results show that high growing temperature significantly changes the biological effects of plants ; moreover, their activity toward different enzymes is specifically affected. Further more detailed analyses into the effect of global warming on cruciferous (Brassicaceae) vegetables bioactivity are needed.

Due to climate change, plants are exposed to abiotic stress, especially high temperatures. To combat those stressful conditions, they developed antioxidant mechanisms which help them to reduce reactive oxygen species. To investigate how high temperature affects the antioxidant potential of broccoli seedlings (Brassica oleracea L. convar. botrytis (L.) Alef. var. cymosa Duch.), in the winter of 2021/2022, within the scope of the TEMPHYS project (IP-2020-02-7585), we cultivated three biological replicas of broccoli seedlings at high temperature (38 °C day/33 °C night) and three biological replicas at regular temperature (23 °C day/18 °C night) as a control group. Extracts of lyophilized broccoli tissue were made in 70% ethanol, and antioxidant potential was measured using four methods: ABTS, DPPH, FRAP and β- carotene bleaching. The obtained values were compared to those of standard Trolox solution of the same concentration as our extracts (i.e. 30 mg/mL for all the methods, except for FRAP which was 15 mg/mL). Based on the results of ABTS, FRAP and β-carotene bleaching method, high temperature significantly increased antioxidant potential of broccoli seedlings. However, DPPH method indicated a reduction of antioxidant potential. All the methods were significantly positively correlated with each other, except the DPPH which was negatively correlated with other methods. Both, at high and regular temperature, statistical methods principal component analysis and hierarchical clustering revealed higher similarity between second and third biological replicas, and separation of first biological replica. However, all biological replicas grown at high temperature tended to cluster together and clearly separated from those at regular temperature. In conclusion, based on three out of four used methods, high temperature significantly increased antioxidant potential of broccoli seedlings, suggesting further research into the effect on plant metabolism.

The main goal of our study was to evaluate the effect of proteins (40 g/L casein), carbohydrates (25 g/L glucose) and oils (5% olive oil) on phytochemical bioavailability, antioxidant, antidiabetic and weight loss activity of gingko leaves standardized extracts after in vitro gastrointestinal digestion. Spectrophotometric methods were used to determine the concentration of total phytochemicals (TP: total phenols, TF: total flavonoids, TPA: total phenolic acids, TFLA: total flavanols, TFLO: total flavonols, TPAN: total proanthocyanidins and TTL: total triterpene lactones), antioxidant (DPPH and FRAP), antidiabetic (inhibition of α-glucosidase and BSA glycation) and weight loss (inhibition of lipase) activity. Ginkgo olive oil formulation had the highest TFLO, TFLA, TPAN and TTL bioavailability after in vitro gastrointestinal digestion. The highest TF and TPA bioavailability had gingko casein formulation. In the gingko water formulations, the highest TP bioavailability was detected. All gingko formulations had high (>70%) antioxidant activity (DPPH and FRAP), high (>70%) enzyme (α-glucosidase and lipase) inhibitory activity and high (>70%) inhibition of BSA glycation after in vitro digestion. According to our results, ginkgo formulation with olive oil has proved to be the formulation with the highest bioavailability of polyphenolic groups and terpene lactones after in vitro gastrointestinal digestion.

Porastom globalne temperature utjecaj na biljke je neizbježan, budući da su one sesilni organizmi, ali nema puno podataka o utjecaju visoke temperature na njihov fitokemijski sastav. Cilj ovog istraživanja bio je istražiti utječe li visoka temperatura i, ako da, u kojem smjeru na udio pigmenata u klijancima brokule. Također, željeli smo utvrditi udio kojih pigmenata klijanaca brokule je podložniji promjeni prilikom uzgoja na visokoj temperaturi. Kako bismo to istražili, uzgojili smo tri biološke replike klijanaca brokule na visokoj temperaturi (38 °C dan/33 °C noć) i tri biološke replike na regularnoj temperaturi (23 °C dan/18 °C noć) kao kontrolnu skupinu. Nakon toga smo liofilizirali tkiva i proveli spektrofotometrijsku analizu udjela klorofila a i b, karotenoida i porfirina. Prema rezultatima, visoka temperatura značajno je smanjila udio svakog od navedenih parametara, osim ukupnih karotenoida koji su se značajno povećali. Najpodložniji pigmenti promjeni udjela bili su ukupni karotenoidi, zatim porfirini i klorofil b, dok je klorofil a bio najstabilniji od analiziranih pigmenata. Zaključno, visoka temperatura značajno je utjecala na sve analizirane pigmente, što sugerira potrebu za istraživanjem utjecaja i na druge fitokemikalije.

Uz trenutne klimatske promjene, biljke su izložene rastućim temperaturama koje utječu na njihov fitokemijski sastav. U sklopu ovog rada cilj je bio istražiti učinak visoke temperature na koncentraciju ukupnih fenolnih spojeva, proteina, glukozinolata i topivih šećera u klijancima brokule (Brassica oleracea L. convar. botrytis (L.) Alef. var. cymosa Duch.), te navedene fitokemikalije sortirati prema stupnju njihove stabilnosti/osjetljivosti spram visoke temperature. U tu svrhu, u zimskim mjesecima 2021./2022. g. uzgojili smo šest bioloških replika klijanaca brokule pri visokoj temperaturi (38 °C dan/33 °C noć) i, kao kontrolu, šest bioloških replika pri regularnoj temperaturi (23 °C dan/18 °C noć). Ekstrakti liofiliziranog tkiva brokule pripremljeni su u različitim otapalima i provedene su spektrofotometrijske analize spomenutih grupa fitokemikalija. Visoka temperatura značajno je povećala koncentraciju ukupnih fenolnih spojeva i topivih šećera u klijancima brokule, ali smanjila koncentraciju ukupnih proteina i glukozinolata. Među testiranim spojevima klijanaca, najosjetljiviji na visoku temperaturu bili su topivi šećeri čija se koncentracija gotovo udvostručila, a najstabilniji ukupni proteini. Zaključno, visoka temperatura specifično je utjecala na različite skupine fitokemikalija u klijancima brokule, što sugerira potrebu daljnjih detaljnijih istraživanja.

Preventing invasive alien plant species (IAPS) introduction and spread is the most efficient strategy to avoid costs arising from IAPS. However, given the current rate of species invasion, IAPS management based mainly on eradication is neither completely effective nor economically viable. Although the economic cost of ecological damages caused by IAPS is significant, their positive influence on human activities and sites is also relevant. One of the positive aspects of some IAPS is their possible use as a source of pharmaceutically active compounds. The research project “NATURe as an ALLY: Alien invasive plants as phytopharmaceuticals – NATURALLY” (IP-2020-02-6899), funded by the Croatian Science Foundation, investigates the phytopharmaceutical potential of extracts of four invasive alien species (Ailanthus altissima, Robinia pseudoacacia, Helianthus tuberosus, and Solidago canadensis) found in Istria (Croatia) as a basis for new ecosystem services. A final goal of the project (2021-2025) is to propose a model for exploring new IAPS provisioning (medicinal) ecosystem services on the pilot territory of Istria. The model will be based on the following elements: a) phytochemical profiling of plant extracts and isolation of specific fractions by liquid chromatography-mass spectrometry (LC-MS) ; b) determination of their antioxidative, antimicrobial, antiproliferative, genotoxic, and cytotoxic properties by functional tests ; c) assessment of the effects (both negative and positive) of selected IAPS using existing and newly developed assessment tools. Preliminary results of RP-HPLC phytochemical profiling indicate the abundance and diversity of bioactive compounds in 70% ethanol extracts of the analysed species. The most commonly detected compounds were: vitamin C, phenolic acids (gallic, benzoic, chlorogenic, vanillic, caffeic, p-coumaric, synapic, and ferulic acid), and flavonoids (quercetin, kaempferol, and isorhamnetin). Antioxidant capacity values expressed as the percentage of reaction inhibition relative to Trolox of the same concentration as the extracts varied from 93.9 to 101.8% for ABTS, 98.4 to 99.1% for FRAP, and 41.4-62% for DPPH assay. Obtained results suggest the potential of invasive plant species as a source of natural antioxidants in medicine and the food industry.

Glukozinolati su sumporom bogati specijalizirani biljni metaboliti zastupljeni u brojnim vrstama reda Capparales, gdje spadaju i prehrambeno značajne vrste porodice Brassicaceae (kupusnjače). Osnovna uloga glukozinolata u biljnom tkivu je obrana od herbivora i patogena. Glukozinolati su inertni sve dok ne dođu u kontakt s enzimom mirozinaza prilikom oštećenja tkiva. Mirozinaza hidrolizira glukozinolate u niz bioaktivnih, toksičnih produkata oporog okusa. Osim kod biotičkog stresa uzrokovanog djelovanjem biljojeda i patogena, glukozinolati sudjeluju i u regulaciji odgovora biljke na abiotičke stresore. Brojna istraživanja dokazala su pozitivan učinak redovitog konzumiranja kupusnjača na ljudsko zdravlje i neki produkti hidrolize glukozinolata posjeduju antikancerogena i protuupalna svojstva. Osim pozitivnog djelovanja na ljudsko zdravlje, pojedini glukozinolati i njihovi produkti razgradnje mogu imati i antinutritivna svojstva. Opisane su i bakterijske mirozinaze koje hidroliziraju glukozinolate u probavnom traktu sisavaca. Kuhanje i drugi procesi obrade biljaka, značajno utječu na bioraspoloživost glukozinolata. S obzirom na njihova ljekovita svojstva, istražuju se novi načini pohrane i obrade biljnog materijala kako bi se spriječio gubitak glukozinolata i maksimizirala bioraspoloživost. Brojna istraživanja posvećena su proučavaju različitih glukozinolata i njihovih produkata hidrolize u svrhu razvoja novih terapeutika. Glucosinolates are sulfur-rich specialized plant metabolites found in the order Brassicales. Glucosinolates play an important role in plant defense against herbivores and pathogens. Upon tissue damage, glucosinolates come into contact with enzyme myrosinase and are hydrolyzed to a variety of bioactive, toxic products of bitter taste. Glucosinolates also play an important role in regulating plant response to abiotic stress. Plenty of research shows that regular consumption of cruciferous vegetables has a positive impact on overall human health. Some products of glucosinolate degradation show anti inflammatory and anticancerogenic properties. There are also reports of antinutritive properties in some glucosinolate derivatives that can lead to a number of metabolic disorders. Other than plant myrosinase, bacterial myrosinases have also been described. Gut microbiota has an important role in glucosinolate hydrolysis in mammalian digestive system. Cooking and other forms of plant tissue processing have a huge impact on glucosinolate availability. Considering the medicinal properties of glucosinolates, there is a lot of effort given in optimizing the existing and finding new methods of storing and processing of vegetables to maximize the bioavailability. Much research is focused in developing new therapeutics based on glucosinolates or their derivatives to fight diseases.

Pojava ekstremnih uvjeta okoliša, kao što su poplave i suše, sve je češća. Biljke se okolišu prilagođavaju promjenama kemijskog sastava. Varijacije kemijskog sastava mogle bi imati značajan utjecaj na nutritivnu vrijednost biljaka, što je posebno važno kod prehrambenih vrsta, uključujući kupusnjače. S obzirom da je pekinški kupus sve zastupljeniji u prehrani, a podataka o njegovom metaboličkom odgovoru na sušu i poplavu nema, cilj ovog diplomskog rada bio je istražiti utjecaj simuliranih uvjeta suše i poplave na sadržaj fenolnih spojeva, šećera i fotosintetskih pigmenata, te antioksidacijski kapacitet ove vrste. Spektrofotometrijski je određen udio ukupnih fenola, flavonoida, hidroksicimetnih kiselina, flavonola, tanina, proantocijanidina, antocijana, topivih šećera te fotosintetskih pigmenata (klorofila a i b, karotenoida). Metodom tekućinske kromatografije visoke moći razlučivanja razdvojeni su, identificirani i kvantificirani kempferol, kvercetin, ferulična, sinapinska i L-askorbinska kiselina. Antioksidacijski kapacitet određen je metodama ABTS, DPPH, FRAP i metodom moći reduciranja. Poplava je uzrokovala povećanje koncentracije ferulične i sinapinske kiseline, kvercetina i kempferola, kao i antioksidacijskog kapaciteta određenog metodom ABTS, međutim smanjenje udjela fotosintetskih pigmenata u kineskom kupusu. Suša je uzrokovala povećanje koncentracije L-askorbinske kiseline. I suša i poplava povećale su udio šećera, a smanjile udio ukupnih tanina u pekinškom kupusu. Ostale mjerene parametre suša i poplava nisu značajno promijenile. Extreme environmental conditions such as flooding and drought are becoming more common. Plants adapt to environment by changing phytochemical composition. Chemical composition variations could have a significant impact on plant nutritional value, which is especially important in plants intensely represented in diet, like most Brassicaceae species. Since Chinese cabbage is increasingly prevalent in diet and there is no information on its metabolic response to water stress, the aim of this work was to investigate the impact of simulated flooding and drought conditions on phenolic compounds content, sugars and photosynthetic pigments, and antioxidant capacity of this species. The content of total phenols, flavonoids, hydroxycinnamic acids, flavonols, tannins, proanthocyanidins, anthocyanins, soluble sugars and photosynthetic pigments (chlorophyll a and b, carotenoids) was determined spectrophotometrically. Using a high-performance-liquid-chromatography method, kaempferol and quercetin, ferulic, sinapic and L-ascorbic acid were separated, identified and quantified. The antioxidant capacity was determined by methods ABTS, DPPH, FRAP and reducing power. Flooding increased ferulic and sinapic acid, quercetin and kaempferol concentration, and antioxidant capacity determined by the ABTS method, however, decreased photosynthetic pigments in Chinese cabbage. Drought increased L-ascorbic acid concentration. Both flooding and drought increased concentration of soluble sugars, and reduced total tannins in Chinese cabbage.

Porodica kupusnjača vrlo je raznolika skupina biljaka, s brojnim varijetetima unutar samih vrsta. Svaka jedinka prilagodila se okolišu u kojem živi uz pomoć posebnih kemijskih spojeva – specijaliziranih metabolita koji svojim fluktuacijama omogućavaju biljkama preživljavanje u stresnim uvjetima. Do sada, najbolje istraženi specijalizirani metaboliti porodice Brassicaceae su glukozinolati. U kupusu u uvjetima povećane koncentracije soli i za vrijeme suše povećava se količina glukozinolata. Povećani salinitet povećao je udio klorofila a i b u kelju, za razliku od ksantofila i karotena čiji udio se smanjio. Kelj pupčar u sušnom razdoblju ima povećane koncentracije nekoliko glukozinolata, kao i količinu ugljikovog izotopa 13C. U brokuli je za porast glukozinolata odgovorna povećana insolacija, nedostatak vode i dovoljan pristup dušiku, dok selenij snižava njihovu količinu. Vitamini C i E, karotenoidi te flavonoid kempferol dobri su indikatori promjena u okolišu u brokuli. Cvjetača u suhim razdobljima pokazuje povećanu koncentraciju glukozinolata i karotenoida. Rotkvici odgovara veća globalna radijacija i salinitet za proizvodnju indolnih glukozinolata. Repa dobro podnosi više temperature i suha razdoblja zahvaljujući većoj produkciji glukozinolata, dok ih smanjena insolacija snižava. Ovi podaci ukazuju na izuzetnu prilagodljivost kupusnjača promjenama u okolišu, kao i mogućnost manipulacije sadržajem njihovih bioaktivnih spojeva upotrebom određenih vanjskih čimbenika. The Brassicaceae family is a highly diverse group of plants with numerous varieties among its species. Each individual has adapted to the enivronment with the help of specific chemical compounds - plant specialized metabolites, whose fluctuations ensure the survival under adverse stress conditions. The most reasearched metabolites inherent to the Brassicaceae family are glucosinolates. During exposure to either elevated salt concentrations or drought, glucosinolates in white cabbage increase rapidly. Greater salinity affects positively the concentration of chlorophylls a and b in Savoy cabbage as opposed to decreased amount of xanthophylls and carotenes under those conditions. Brussel sprouts response to the drought by increasing the concentration of several glucosinolates as well as stable carbon isotope 13C. Greater insolation, decreased water level and nitrogen supplementation increased the concentration of glucosinolates in broccoli. Vitamins C and E, carotenoids and the flavonoid kaempferol are excellent indicators of environmental stress in broccoli. Cauliflower increases the concentrations of glucosinolates and carotenoids in period of drought. Higher insolation and salinity induces the production of indolic glucosinolates in radish. Turnip tolerates higher temperatures and droughts stress due to increased amount of glucosinolates, but they rapidly decrease when the exposure to light is insufficient. These data indicate that cruciferous vegetables are extremely adaptive to abiotic stresses, which leads to conclusion that by applying the right exogenous factors, it could be possible to manipulate the concentration of their bioactive compounds.

Alkaloidi su jedna od najvećih skupina biljnih specijaliziranih metabolita zbog svoje raznolikosti struktura i biosintetskih puteva. Morfij je prvi alkaloid izoliran 1804. godine u kristalnom obliku iz opijumskog maka. Više od 20 000 alkaloida izolirano je od otkrića morfija. Niskomolekularni su spojevi koji su alkalni zbog prisustva heterocikličkog prstena koji sadrži dušikov atom. Te spojeve proizvode uglavnom cvjetnice i neke životinje. Neke biljne porodice kao Papaveraceae, Ranunculaceae, Amaryllidaceae, Solanaceae, Apocynaceae, Asteraceae, Berberidaceae, Boraginaceae, Fabaceae vrlo su bogate alkaloidima. Alkaloidi su zanimljiva skupina spojeva širokog spektra djelovanja, nepoželjnih i poželjnih učinaka na životinjske i ljudski organizam. Djeluju antibakterijski, antimitotički, protuupalno, analgetski, lokalno anestetski, hipnotički, psihotropno i protiv tumora. Obuhvaćaju neuroaktivne molekule, poput kofeina i nikotina, te djeluju kao stimulansi i lijekovi, primjerice kodein, morfij, vinblastin i vinkristin. Alkaloids are basically one of the largest groups of plant-specialized metabolites as a result of their diversity of structures and biosynthetic pathways. In 1804, morphine was the the first alkaloid to be isolated in crystalline form from opium poppy. Since the discovery of morphine, more than 20,000 alkaloids have been isolated. Low molecular weight compounds are alkaline due to the presence of a heterocyclic ring containing a nitrogen atom. These compounds are mostly produced by flowering plants and some animals. Some plant families like Papaveraceae, Ranunculaceae, Amaryllidaceae, Solanaceae, Apocynaceae, Asteraceae, Berberidaceae, Boraginaceae, Fabaceae are very rich in alkaloids. Alkaloids as such are an interesting group of compounds with a broad spectrum of overall effectiveness, and undesirable and desirable effects on animal and human organisms. They have antibacterial, antimitotic, anti-inflammatory, analgesic, local anesthetic, hypnotic, psychotropic and antitumor effects. Finally, alkaloids also include neuroactive molecules, such as caffeine and nicotine, and act as stimulants and drugs, some of which include codeine, morphine, vinblastine and vincristine.

Raštika (Brassica oleracea L. var. acephala) je biljka iz porodice kupusnjača bogata specijaliziranim metabolitima s pozitivnim utjecajima na ljudsko zdravlje. U Hrvatskoj nije razvijena komercijalna proizvodnja sjemena te postoji znatna intra- i interpopulacijska varijabilnost. U ovom radu hidroponski je uzgojena raštika čije je sjeme bilo podrijetlom iz Mostara, Vrgorca, Gornje Brele, Pule, Pelješca i od komercijalnog proizvođača Bejo te su ispitani klijavost, morfološke karakteristike, sadržaj specijaliziranih metabolita i antioksidacijska aktivnost kako bi se odredilo potencijalne razlike između populacija. Najbolju klijavost i prinos pokazale su populacije iz Mostara i Vrgorca, a najmanju ona s Pelješca. Sadržaj ukupnih polifenola, fenolnih kiselina, glukozinolata i karotenoida nije se statistički značajno razlikovao u uzorcima uzgojenim od različitih proizvođača sjemena. Sadržaj ukupnih flavonoida bio je statistički najviši kod raštike od proizvođača sjemena s Pelješca dok je najvišu antioksidacijsku aktivnost pokazala raštika uzgojena iz sjemena iz Vrgorca. Sve istražene populacije sadrže značajne količine specijaliziranih metabolita na koje podrijetlo sjemena nema značajan utjecaj (osim na sadržaj ukupnih flavonoida i antioksidacijsku aktivnost). Kale (Brassica oleracea L. var. acephala) is a cruciferous plant rich in specialized metabolites with positive effects on human health. There is no commercially available kale seeds in Croatia what resultes with the considerable intra- and interpopular variability. In the present work, we grown soilless plants from the seeds originated from Mostar, Vrgorac, Gornja Brela, Pula, Pelješac and from only commercial producer Bejo in order to determinate the influence of seed origin on germination percentige, morphological characteristics, specialized metabolites level and antioxidant activity. The best germination and yield had populations from Mostar and Vrgorac while the smallest ones has Peljesac. The content of total polyphenols, phenolic acids, glucosinolates and carotenoids did not differ significantly in the samples grown from different seed producers. The content of total flavonoids was the highest in kale from Peljesac while the highest antioxidant activity was shown by kale from Vrgorac seeds. All evaluated populations contain significant amounts of specialized metabolites with health benefites and seed origin mostly did not have significant effect on metabolites level, except slightly on the total flavonoid content and antioxidant activity.

Sadržaj fenolnih spojeva, kao i njihov antioksidacijski kapacitet, ovise o razvojnom stadiju biljke. Do sada su u dostupnoj literaturi informacije o sadržaju fenolnih spojeva i antioksidacijskom kapacitetu pekinškog kupusa (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) zabilježene za odrasle biljke, no ne postoje usporedni podaci o kvalitativnom i kvantitativnom sadržaju fenolnih spojeva i antioksidacijskom kapacitetu različitih razvojnih stadija ove vrste. Stoga je u ovom radu ispitano pet različitih razvojnih stadija pekinškog kupusa; prvi stadij su činile mlade biljke s otvorenim kotiledonama, drugom stadiju pripadale su biljke s razvijenim dvjema kotiledonama i dva prava lista, trećem biljke s četiri lista, a biljke četvrtog i petog stadija imale su po šest, odnosno deset razvijenih listova. Spektrofotometrijski je određen sadržaj ukupnih fenola, flavonola i hidroksicimetnih kiselina, metodom tekućinske kromatografije visoke moći razlučivanja su identificirani i kvantificirani najzastupljeniji pojedinačni flavonoidi i fenolne kiseline, te je određen antioksidacijski kapacitet pet razvojnih stadija pekinškog kupusa metodama koje se temelje na redukciji radikala 2,2'-azinobis (3- etilbenzotiazolin-6-sulfonske kiseline) i 2,2-difenil-pikrilhidrazila, te metodom određivanja antioksidacijske jakosti redukcijom željeza. Rezultati su pokazali da se najraniji stadij (samo kotiledone) pekinškog kupusa na razini količine ukupnih fenola, flavonola, hidroksicimetnih kiselina i kvercetina, kao i antioksidacijskog kapaciteta statistički ne razlikuje (p≤0.05) od stadija sa šest ili deset listova. Ova tri stadija ujedno imaju i značajno veće vrijednosti spomenutih parametara u odnosu na stadij s kotiledonima i dva prava lista ili stadij s četiri lista. Phenolic compounds content so as their antioxidant capacity depend on plant development stage. In the present literature, informations on the phenolic compounds content and antioxidant capacity of Chinese cabbage have been reported for mature plants, but there are no comparative data on the qualitative and quantitative phenolic compounds content and antioxidant capacity of Chinese cabagge different development stages. Therefore, in this study, five different development stages of Chinese cabbage were investigated; the first stage consisted of plants with developed cotyledones, the second stage were plants with developed two cotyledones and two leaves, the third stage consisted of plants with four leaves, and the plants of the fourth and fifth stages had six or ten developed leaves. Content of total phenols, flavonols and hydroxycinnamic acids was measured spectrophotometrically, most abundant individual flavonoids and phenolic acids were identified and quantified using High-Performance Liquid Chromatography method, and antioxidant activity of five different stages of Chinese cabbage were determined using methods based on a reduction of radicals 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) and 2,2-diphenyl-1-picryl-hydrazyl, and Ferric reducing/Antioxidant power method. The results showed that the earliest stage (containing cotyledones only) of Chinese cabbage, at the level of total phenols, flavonols, hydroxycinnamic acids and quercetin as well as antioxidant capacity does not statistically differ (p≤0.05) from the stages with six or ten leaves. These three stages also have significantly higher values of the mentioned parameters compared to the stage with the cotyledons and two leaves or the stage with four leaves.

Biljni sekundarni metaboliti su spojevi koji nisu nužni za rast i razvoj biljaka, ali im omogućavaju prilagodbu i preživljavanje u okolišu. Strukturna kompleksnost i raznolikost sekundarnih metabolita osigurala im je važnu ulogu u farmaceutskoj industriji. Ovi spojevi koriste se u liječenju različitih medicinskih stanja kao što su tumori, neurodegenerativne bolesti, parazitske bolesti s naglaskom na malariju, metabolički poremećaji te glaukom. Biljni sekundarni metaboliti mogu biti izravno korišteni kao lijekovi za kliničku upotrebu, kao npr. galantamin, vinblastin i kinin. Sintetska optimizacija često je potrebna kako bi se povećala dostupnost samog spoja, u tom slučaju koriste se kao prototip za sintezu velikog broja strukturnih analoga koji mogu biti korišteni u razvoju lijekova. Dobri primjeri ovakve uporabe su paklitaksel, nitizinon i oseltamivir fosfat. Također, mogu biti korišteni i kao farmakološki i biokemijski alati u istraživanju mehanizama koji dovode do bolesti. Neki od spojeva korišteni u tu svrhu su genistein, kvercetin i forskolin. Plant secondary metabolites are compounds not essential for plant growth and development, but are useful for adjustment and survival of plants in environment. Secondary metabolites structural complexity and diversity has ensured them an important role in pharmaceutical industry. Plant secondary metabolites are used for treatment of various medical conditions such as cancer, neurodegenerative diseases, parasitic diseases with emphasis on malaria, metabolic disorders and glaucoma. These compounds can be used directly as drugs in clinical use, like galantamine, vinblastine and quinine. Synthetic optimization is often required to increase bioavailability, in that case plant secondary metabolites serve as prototypes for the synthesis of high number of structural analogs that can be used in drug development. Good examples for such use are paclitaxel, nitisinone and oseltamivir phospate. Further, plant secondary metabolites can also serve as pharmacological and biochemical probes to help explain the mechanisms underlying human diseases. Some of the compounds used for this purpose are genistein, quercetin and forskolin.

U sklopu ovog rada metodom tekućinske kromatografije visoke moći razlučivanja istraţen je utjecaj vodenih ekstrakata gospine trave, koprive i kadulje, te flavonoida kempferola i izoramnetina, odnosno kiselina ferulične i p-kumarinske na sadrţaj flavonoida i hidroksicimetnih kiselina u klijancima pekinškog kupusa (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt). Rezultati su pokazali da je vodeni ekstrakt gospine trave znatno povećao količinu kvercetina, što ukazuje na mogućnost korištenja ovog vodenog ekstrakta za obogaćivanje klijanaca pekinškog kupusa kvercetinom. S obzirom da su za kvercetin zabiljeţeni brojni pozitivni biološki učinci, obogaćivanje biljaka ovim flavonoidom moglo bi imati potencijal u proizvodnji biljnog materijala vrijednog za industrijsku primjenu (npr. poljoprivrednu, prehrambenu i farmaceutsku). Rezultati su takoĎer pokazali da je vodeni ekstrakt kadulje znatno povećao količinu kempferola, kavene, ferulične i sinapinske kiseline, ali ujedno je i negativno utjecao na rast i razvoj klijanaca pekinškog kupusa. Od fenolnih spojeva jedino je tretman p-kumarinskom kiselinom znatno povećao koncentraciju kavene kiseline u klijancima pekinškog kupusa. Pekinški kupus vrlo je zastupljena prehrambena vrsta iz porodice krstašica (Brassicaceae) zahvaljujući visokom sadrţaju vitamina i minerala, a obogaćivanjem njenog fenolnog profila dodatno se doprinosi njenoj prehrambenoj vrijednosti. In this work, using high performance liquid chromatography method, the influence of St. John's wort, nettle and sage aqueous extracts, and flavonoids kaempferol and isorhamnetin, or ferulic and p-coumaric acid on the content of flavonoids and hydroxycinnamic acids in Chinese cabbage (Brassica rapa L. subsp. pekinensis (Lour.) Hanelt) seedlings was investigated. The results showed that St. John's wort extract significantly increased the amount of quercetin, indicating the possibility of using this extract to enrich Chinese cabbage seedlings with quercetin. Given that quercetin exerts numerous positive biological effects, enrichment of plants with this flavonoid may have potential in the production of plant material valuable for industrial applications (e.g. agricultural, food and pharmaceutical). The results also showed that the water extract of sage significantly increased the amount of kaempferol, caffeic, ferulic and sinapic acid, however this extract also negatively affected the growth and development of Chinese cabbage seedlings. Among phenolic compounds, only treatment with p-coumaric acid significantly increased the concentration of caffeic acid in Chinese cabbage seedlings. Chinese cabbage is a very often used vegetable from the family Brassicaceae thanks to the high content of vitamins and minerals, and the enrichment of its phenolic profile further contributes to its nutritional value.