Optimizacija ekstrakcije lista japonskega dresnika (Fallopia japonica) s pristopom načrtovanja eksperimentov ter vrednotenje sestave in antioksidativne aktivnosti ekstraktov

Marolt, Ana (author), Kočevar Glavač, Nina (mentor), Schoss, Katja (co-mentor)

Japonski dresnik je zelnata trajnica, ki je zaradi svoje sposobnosti širjenja v različne vrste habitatov postala ena izmed najbolj invazivnih evropskih tujerodnih vrst. V nasprotju z negativnim vplivom na okolje je pomembna rastlina na področju ljudske medicine. Že več kot tisoč let ga v tradicionalni kitajski medicini uporabljajo za zdravljenje različnih bolezni, pomembno mesto pa ima tudi na področjih farmacije in kozmetike. Namen magistrske naloge je s pomočjo načrtovanja eksperimentov (angl. design of experiments – DoE) določiti optimalne pogoje za ekstrakcijo izbranih spojin v japonskem dresniku in ovrednotiti antioksidativno aktivnost izvlečkov. Razvili smo občutljivo, natančno in ponovljivo metodo HPLC za ugotavljanje vsebnosti preiskovanih spojin in ovrednotili antioksidativno aktivnost posameznih ekstraktov s testi DPPH (1,1-difenil-2-pikrilhidrazil), ABTS (2,2-azino-bis(3-etilbenzotiazolin-6-sulfonska kislina)) in FC (Folin-Ciocalteu). Ugotovili smo, da 1 g izvlečka povprečno vsebuje največ piceida (9,21 mg/g izvlečka), sledijo klorogenska kislina (4,41 mg/g), emodin-8-glukozid (3,52 mg/g) in emodin (1,36 mg/g), najmanj pa vsebuje resveratrola (0,37 mg/g). Podatki, pridobljeni za skupne fenolne spojine, so v povprečju znašali 128,6 mg ekvivalenta galne kisline/g izvlečka (18,76 % RSD). Antioksidativno delovanje izvlečkov, ovrednoteno s testom ABTS, je bilo povprečno 663,9 mg ekvivalenta galne kisline/g (1,15 % RSD) in pri testu DPPH 297,6 mg ekvivalenta galne kisline/g (3,08 % RSD). Dokazali smo, da listi japonskega dresnika, ki raste v Sloveniji, vsebujejo vseh pet preiskovanih spojin in izkazujejo antioksidativne lastnosti. S pomočjo DoE smo optimizirali ekstrakcijo listov japonskega dresnika in določili najbolj optimalne pogoje: koncentracija etanola 52,84 %, razmerje med rastlinsko drogo in topilom 1: 10,14 in čas ekstrakcije 45 min. Temu je ustrezal izvleček N5. Pri vseh merjenih odzivih se je za najpomembnejši parameter ekstrakcije izkazala koncentracija etanola. Na podlagi naših ugotovitev zaključujemo, da bi lahko nadzemne dele, ki jih v industriji pogosto zavržejo, uporabili kot nov vir antioksidantov.

• Language: Slovenian
• Keywords: antioksidativna aktivnost, Fallopia japonica, japonski dresnik, optimizacija ekstrakcije
• Work type: Master's thesis/paper
• Organization: FFA - Faculty of Pharmacy
• Year: 2024
• PID: 20.500.12556/RUL-155989
• Publication date in RUL: 26.04.2024

Secondary language

• Language: English
• Title: Optimization of Japanese knotweed (Fallopia japonica) leaf extraction using a design of experiments approach and evaluation of the composition and antioxidant activity of the extracts

Abstract

Japanese knotweed is an herbaceous perennial that has become one of Europe's most invasive species due to its ability to spread into different types of habitats. In contrast to its negative impact on the environment, it is an important plant in the field of folk medicine. It has been used for more than a thousand years in traditional Chinese medicine to treat various diseases, and has an important place in the pharmaceutical and cosmetic fields. The aim of this master thesis is to determine the optimal conditions for the extraction of selected compounds in Japanese knotweed and to evaluate the antioxidant activity of the extracts by design of experiments (DoE). We have developed a sensitive, accurate and reproducible HPLC method for the determination of the content of the compounds investigated and the antioxidant activity of the individual extracts was evaluated by DPPH, ABTS and FC assays. We found that 1 g of extract contained on average the highest amount of piceid (9,21 mg/g extract), followed by chlorogenic acid (4,41 mg/g), emodin-8-glucoside (3,52 mg/g) and emodin (1,36 mg/g), and the lowest amount of resveratrol (0,37 mg/g). The data obtained for total phenolic compounds averaged 128,6 mg gallic acid equivalent/g extract (18,76 % RSD). The antioxidant activity of the extracts evaluated by the ABTS test averaged 663,9 mg gallic acid equivalent/g (1,15 % RSD) and by the DPPH test 297,6 mg gallic acid equivalent/g (3,08 % RSD). We have shown that the leaves of the Japanese knotweed, which grows in Slovenia, contain all five compounds tested and exhibit antioxidant properties. DoE was used to optimise the extraction of Japanese knotweed leaves and to determine the most optimal conditions: ethanol concentration 52.84%, drug to solvent ratio 1: 10.14 and extraction time 45 min. For all measured responses, the most important extraction parameter was the ethanol concentration. Based on our findings, we conclude that the above-ground parts, which are often discarded in the industry, could be used as a new source of antioxidants.

• Keywords: antioxidant activity, Fallopia japonica, japanese knotweed, extraction optimization