Purification, derivatization of piperine from black pepper (Piper nigrum L.) and determination of biological activities of the derivatives obtained

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Thesis Type: Doctorate

Institution Of The Thesis: Erzincan Binali Yildirim University, Fen Bilimleri Enstitüsü, KİMYA ANABİLİM DALI, Turkey

Approval Date: 2025

Thesis Language: Turkish

Student: TUBA NUR SUYURDU

Supervisor: EKREM KÖKSAL

Open Archive Collection: AVESIS Open Access Collection

Abstract:

In this thesis, piperine, a natural alkaloid obtained from the black pepper plant (Piper nigrum L.), was purified; then, eight new derivatives were synthesized by various chemical modifications to its structure. The main objective of the study was to evaluate the possibility of increasing the biological activity of piperine derivatives and to comparatively reveal the enzyme inhibitory, antioxidant, anticancer and antifungal activities of these derivatives with the original molecule. In the AChE assay, piperine (1) (IC50 = 43.45 µM) showed stronger inhibition than the reference inhibitor tacrine (IC50 = 54.65 µM). The ethyl ester (3b) molecule (IC50 = 63.64 µM) showed similar activity to the reference drug acarbose (62.43 µM) in inhibiting α-glucosidase. The strongest DPPH activity (IC50 = 113.69 µg/mL) was observed in the piperic acid (2) molecule, and the highest capacity in the reduction test was determined in the isopentyl ester (3e) molecule (27.78 µM Trolox equivalent). Antiproliferative activity: Piperic acid showed the highest cytotoxic effect (IC50 = 29.65 µM) in the A549 cell line. The antifungal effects of the derivatives were evaluated on Botrytis cinerea by the agar diffusion method. Compound 4 was the application that most effectively suppressed spore development with 60% germination in 50 µL and 89 µm germ tube. The findings show that the structure of piperine can be achieved with versatile biological activities through appropriate chemical modifications.