Date of Publication

7-31-2026

Document Type

Bachelor's Thesis

Degree Name

Bachelor of Science in Chemistry

Subject Categories

Chemistry

College

College of Science

Department/Unit

Chemistry

Thesis Advisor

Raymond S. Malabed

Defense Panel Member

Mariafe N. Calingacion
Joan Candice V. Ondevilla

Abstract (English)

This study determined the antioxidant activity, total phenolic content (TPC), total flavonoid content (TFC), and protein content of Annona muricata (guyabano) and Annona squamosa (atis) fruit flesh methanolic extracts. For each species, samples of the extracts (in triplicate) and their respective blanks and standards were subjected to aluminum nitrate colorimetric assay for TFC (standard: quercetin), Folin-Ciocalteu method for TPC (standard: gallic acid), Bradford assay for protein content (standard: bovine serum albumin), and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay for half-maximal inhibitory concentration (IC50) determination (standard: ascorbic acid), making use of UV-Vis spectroscopy for standard curve generation. For guyabano and atis, respectively, the following values were obtained: TFC = 0.030 ± 0.002 and 0.147 ± 0.002 mg QE/g (coefficients of variation = 3% and 0.5%), TPC = 0.683 ± 0.006 and 2.72 ± 0.04 mg GAE/g (0.4% and 0.64%), protein content = 0.344 ± 0.037 and 1.36 ± 0.04 mg BSA/g (4% and 1%), and IC50 = 48.92 and 15.79 mg/mL, all of which showed small coefficients of variation and significant differences between the two samples for the first three tests (p < 0.05 from Student t-test, 95% confidence level, unpooled, two-tailed). Atis pulp consistently showed greater antioxidant activity and protein content, inferably due to its lower water content and denser cellular matrix. Gas chromatography-mass spectrometry (GC-MS) characterization with derivatization did not detect the expected phenolics and flavonoids like gallic acid and quercetin; instead, minor phenolic compounds such as liriodendromine were putatively detected, possibly due to an incomplete diethysilane reaction to lower the desired compounds’ boiling point. Overall, this study had shed light on the underexplored topics of antioxidant activity and protein content of home-grown guyabano and atis fruit flesh, likewise agreeing with other local and foreign studies regarding the fruit part having very low content.

Keywords: Annona muricata, Annona squamosa, antioxidant activity, GC-MS characterization, half-maximal inhibitory concentration, protein content, total flavonoid content, total phenolic content

Abstract Format

html

Abstract (Filipino)

Tinukoy ng pag-aaral na ito ang antioxidant activity, total phenolic content (TPC), total flavonoid content (TFC), at protein content ng methanolic extracts ng laman ng prutas (fruit flesh) ng Annona muricata (guyabano) at Annona squamosa (atis). Isinailalim ang tatlong replicate (triplicate) ng bawat extract sample, kabilang ang mga kinakailangang blank at standard, sa aluminum nitrate colorimetric assay para sa TFC (standard: quercetin), Folin-Ciocalteu method para sa TPC (standard: gallic acid), Bradford assay para sa protein content (standard: bovine serum albumin), at 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay para sa pagtukoy sa half-maximal inhibitory concentration (IC50) (standard: ascorbic acid), gamit ang UV-Vis spectroscopy para sa pagbuo ng mga standard curve. Para sa guyabano at atis, ayon sa pagkakabanggit, nakuha ang mga sumusunod na resulta: TFC = 0.030 ± 0.002 at 0.147 ± 0.002 mg QE/g (mga coefficient of variation = 3% at 0.5%), TPC = 0.683 ± 0.006 at 2.72 ± 0.04 mg GAE/g (0.4% at 0.64%), protein content = 0.344 ± 0.037 at 1.36 ± 0.04 mg BSA/g (4% at 1%), at IC50 = 48.92 at 15.79 mg/mL; ang lahat ng ito ay nagpakita ng mabababang coefficient of variation at ng mga makabuluhang pagkakaiba (significant differences) sa pagitan ng dalawang sample para sa unang tatlong assay (p < 0.05 batay sa Student t-test, 95% confidence level, unpooled, two-tailed). Patuloy na nagpakita ang laman ng prutas ng atis ng mas mataas na antioxidant activity at protein content; mahihinuha ito mula sa mas kaunting nilalamang tubig at mas siksik na cellular matrix ng prutas. Hindi natukoy ng karakterisasyon batay sa gas chromatography-mass spectrometry (GC-MS) na may deribatisasyon ang mga inaasahang phenolics at flavonoids tulad ng gallic acid at quercetin; sa halip, mga minor na phenolic compound tulad ng liriodendromine ang ipinagpalagay na natukoy; maaaring dulot ito ng di-kumpletong reaksyon ng diethylsilane upang maibaba ang boiling point ng mga inaasahang makitang compound. Sa kabuuan, nagbigay-linaw ang pag-aaral na ito sa antioxidant activity at protein content ng laman ng prutas ng mga lokal na guyabano at atis, mga paksang hindi pa gaanong nasasaliksik. Sumasang-ayon din ang mga resulta sa iba pang lokal at dayuhang pag-aaral pagdating sa pagkakaroon ng napakababang nilalamang antioxidant at protina ng mga prutas na ito.

Mga susing-salita: Annona muricata, Annona squamosa, antioxidant activity, GC-MS characterization, half-maximal inhibitory concentration, protein content, total flavonoid content, total phenolic content

Abstract Format

html

Language

English

Format

Electronic

Keywords

Annona; Antioxidants; Flavonoids

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Embargo Period

9-7-2027

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Available for download on Tuesday, September 07, 2027

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