Date of Completion

2025

Document Type

Thesis

Degree Name

Bachelor of Science in Biochemistry

Keywords

Tomatoes

Abstract

The rapid post harvest ripening and spoilage of climacteric fruits like tomatoes present a challenge on the agricultural systems of tropical countries, contributing to food and economic loss. Ethylene is a plant hormone that regulates developmental and physiological processes and this study aimed to explore the inhibitory potential of locally sourced, plant-derived terpenes against the key enzymes that synthesize ethylene namely, ACC synthase and ACC oxidase to possibly delay ripening and extend shelf life. A total of 50 terpenes were molecularly docked against the aforementioned enzymes using S-adenosyl methionine (SAM) as a reference ligand. Among them, three compounds namely α-terpinene (-6.512 kcal/mol) from lemongrass, limonene from calamansi, and caryophyllene (5.836 kcal/mol) from guava were top candidates based on binding affinity. Crude extracts were obtained from dried leaves of the respective plants using ultrasonic-assisted extraction and rotary evaporation with n-hexane as a solvent for both processes. Calamansi extract yielded 1 gram from 100 grams of dried leaves, corresponding to a percentage yield of 1.40%. Two trials of treated tomatoes were qualitatively monitored over 21 days using a 5-stage ripening scale. In Trial 1 a 15% delay in reaching stage 4 (signs of wilt, wrinkled) was observed with lemongrass, and 33% with calamansi. Guava showed no delay in reaching stage 4 but delayed stage 3 (red-orange) by 18%. In trial 2, guava delayed stage 4 by 8.33%, lemongrass by 28.33% and calamansi by 40%. Preliminary characterization of calamansi extract via infrared spectroscopy (IR) suggested the presence of characteristic alkene functional groups, while GC-MS analysis identified ten major terpene constituents, which were among the identified compounds from the molecular docking were namely alpha-pinene, beta-pinene, alpha-terpineol, Limonene, Caryophyllene, Bisabolene, Linalool, Farnesol, and Camphene, with Linalool yielding the highest concentration out of the terpenes with 1.2941% composition. Both molecule docking and experimental results indicate that terpene rich calamansi extract has capabilities of delaying ripening and spoilage.

First Advisor

Margel C. Bonifacio, RCh, PhD

Download

Share

COinS