Ethnobotanical research of pear varieties (Pyrus communis L.) from Central and Southwest Serbia and biological activity of fruit extracts

[A. Savić]

204 str.

Biologija - Morfologija, fitohemija i sistematika biljaka / Biology - Morphology, phytochemistry and systematics of plants

Plod kruške se koristi u ljudskoj ishrani od nastanka ljudskog roda, pa do današnjih dana. Osim prijatnog ukusa, za ljudsku ishranu je od značaja njegov hemijski sastav, prisustvo antioksidanasa i visoka biološka aktivnost. Brojna etnobotanička istraživanja ukazuju da se kruška koristi u etnomedicinske svrhe širom sveta i na Balkanskom poluostvu. Cilj ove doktorske disertacije je utvrđivanje diverziteta autohtonih sorti krušaka na području centralne (rudničko-takovski kraj) i jugozapadne Srbije (srednje i donje Polimlje), etnobotaničko istraživanje, hemijska analiza metanolnih ekstrakata ploda i delova ploda odabranih sorti kruške (pokožica, meso) i utvrđivanje njihove biološke aktivnosti (antioksidativne, antineurodegenerativne, antidijabetične i citotoksične). Etnobotaničko istraživanje je rađeno metodom polu-struktuiranog intervjua, fizičko-hemijska analiza je rađena standardnim metodama, a fitohemijska karakterizacija je urađena korišćenjem spektrofotometrijskih metoda i HPLC-DAD analizom. Biološka aktivnost ekstrakata ploda je utvrđena testiranjem njihove antioksidativne, antineurodegenerativne, antidijabetične i citotoksične aktivnosti. Etnobotaničkom analizom je utvrđeno prisustvo 28 autohtonih sorti na području rudničko- takovskog kraja i 26 sorti na području Polimlja. Etnomedicinska upotreba kruške je izraženija u Polimlju. Ekstrakti ploda autohtonih sorti krušaka su bogati sekundarnim metabolitima, posebno iz grupe fenolnih jedinjenja. Pojedine sorte (Takiša i Lončara) imaju visoku vrednost ukupnog sadržaja fenola u ekstraktu ploda, a pokožica sadrži višu vrednost sadržaja ukupnih fenola u odnosu na meso. Najzastupljenije fenolne komponente u pokožici su hlorogenska kiselina, arbutin i kvercitrin. Ekstrakti autohtonih plodova krušaka pokazali su značajnu antioksidativnu aktivost, a u testovima koji se baziraju na različitim antioksidativnim mehanizmima izdvojile su se Takiša, Lončara i Jeribasma. Svi testirani uzorci su slabo do umereno inhibirali aktivnost AChE, dok je najvišu TYR inhibitornu aktivnost pokazala pokožica Takiše, što je značajno za dalja istraživanja antineurodegenerativne aktivnosti. Rezultati dobijeni ispitivanjem antidijabetične aktivnosti pokazuju da su ispitivani uzorci slabo inhibirali α-amilazu, dok je inhibicija α-glukozidaze bila veoma značajna. Posebno su se izdvojili ekstrakti Takiše, Lončare i Jeribasme, što je značajno za dalja ispitivanja ploda kruške kao potencijalno antidijabetičnog sredstva. Testirani ekstrakti su imali umeren citotoksični efekat na ćelije kolorektalnog karcinoma, dok je najveći citotoksični efekat pokazao ekstrakt ploda evropske kruške. Najveću biološku aktivnost su pokazale Takiša, a zatim Lončara, Jeribasma i evropska kruška, čime se otvara mogućnost za njihova dalja istraživanja u ishrani i u lekovite svrhe.

The pear fruit has been used in human nutrition from the dawn of mankind to modern times. Apart from its pleasant taste, its chemical composition, and the presence of antioxidants and high biological activity are also important for human nutrition. Numerous ethnobotanical studies indicate that the pear is used for ethnomedicinal purposes all over the world and also in the Balkans. The aim of this doctoral dissertation was to determine the diversity of autochthonous pear varieties in the area of central (Rudničko-Takovski region) and south-western Serbia (Central and Lower Polimlje), ethnobotanical research, chemical analysis of methanol extracts of pear fruit and fruit parts (peel, flesh) and the assessment of their biological activity (antioxidant, antineurodegenerative, antidiabetic and cytotoxic). The ethnobotanical analysis was carried out by the method of semi-structured interview, physical-chemical analysis using standard methods, and the phytochemical characterisation using spectrophotometric methods and HPLC-DAD. The biological activity of the fruit extracts was determined by testing their antioxidant, antineurodegenerative, antidiabetic and cytotoxic activity. The ethnobotanical analysis revealed the presence of 28 autochthonous varieties in the Rudničko-Takovski region and 26 varieties in the Polimlje region. The ethnomedicinal use of pear fruit is more intensive in Polimlje. The fruit extracts of autochthonous pear varieties are rich in secondary metabolites, especially from in phenolic compounds. Takiša and Lončara have a high total phenolic content in the fruit extract, and the peel contains a higher total phenolic content than the flesh. The most abundant phenolic components in the peel were chlorogenic acid, arbutin and quercitrin. Extracts from autochthonous pear fruit showed significant antioxidant activity. In the tests based on different antioxidant mechanisms, Takiša, Lončara and Jeribasma showed the strongest activity. All samples of pear fruit extracts showed low to moderate AChE inhibitory activity, while the highest TYR inhibitory activity was exhibited by the peel of Takiša, which is important for future antineurodegenerative research. The results obtained in testing the antidiabetic activity showed that the pear fruit extracts weakly inhibited α-amylase, while the inhibition of α-glucosidase was significant. The extracts from Takiša, Lončara and Jeribasma had the strongest antidiabetic activity, which is important for further testing of pear fruit as a potential antidiabetic agent. The extracts tested showed moderate cytotoxic activity on colorectal cancer cells, with the extract from European pear fruit having the strongest effect. The significant biological activity was shown by the Takiša, followed by the Lončara, the Jeribasma and the European pear, which opens the possibility for further research in the field of nutrition and medicine.

Pyrus; kruške; autohtone sorte; agrobiodiverzitet; etnobotanička upotreba; metanolni ekstrakti; hemijska karakterizacija; biološka aktivnost

Pyrus; pears; autochtonous varieties; agrobiodiversity; ethnobotanical use; methanol extracts; chemical characterization; biological activity

582.639.22:581.6(497.11)(043.3)

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