Abstract

Background:
Edible bird’s nest (EBN), produced by swiftlets from salivary gland secretions, is a valuable glycoprotein source that offers significant nutritional benefits, particularly influencing lipid metabolism for consumer health. Processing methods like cleaning, bleaching, drying, and enzyme-based techniques can alter the physical quality, nutritional value, and bioactive characteristics of EBN.

Aim:
This study aimed to compare the effects of raw and commercialized EBN extracts on cell viability, total cellular cholesterol (TCC), and low-density lipoprotein receptor (LDLR) gene expression in HepG2 cells.

Methods:
HepG2 cells were cultured under controlled laboratory conditions and treated with graded concentrations of raw and commercialized EBN extracts. Cell viability was evaluated using the MTT assay. Intracellular cholesterol levels were quantified enzymatically, and LDLR gene expression was measured using reverse transcription quantitative PCR.

Results:
Raw EBN maintained higher cell viability and exhibited a non-linear dose–response pattern, whereas commercialized EBN produced a clear dose-dependent cytotoxic effect. Both raw and commercialized EBN markedly upregulated LDLR gene expression, increasing transcription approximately 23-fold and 24.5-fold, respectively, compared with untreated controls. Total cellular cholesterol did not differ significantly (p>0.05), with TCC values of 1.85 ± 0.65, 1.80 ± 0.91, 2.07 ± 0.29, 1.90 ± 0.92, and 3.04 ± 1.04 µmol cholesterol/µmol protein in the BC, NC, PC, raw EBN, and commercialized EBN groups, respectively, although commercialized EBN showed the highest level, representing approximately a 1.6-fold increase relative to BC.

Conclusion:
Both raw and commercialized EBN significantly enhance LDLR gene expression in HepG2 cells, indicating their potential to promote cholesterol uptake. Nonetheless, processing may alter the biochemical composition and biological activity of EBN, contributing to differences in cytotoxicity and cholesterol response. These findings provide molecular insight into EBN’s potential as a functional food for cholesterol regulation and highlight the importance of processing integrity in preserving its bioactive efficacy.

Key words: Cholesterol metabolism; Edible Bird’s Nest; HepG2 cells; LDLR gene expression; Lipid regulation.