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ANTIOXIDANT ACTIVITY OF KAFFIR LIME (Citrus hystrix) PEEL ETHANOLIC EXTRACT AFFECTING INTESTINAL BARRIER UNDER HYDROGEN PEROXIDE-INDUCED OXIDATIVE STRESS IN CACO-2 CELLS

Chrisyella Cendara Purba, Dr. Widiastuti Setyaningsih, S.T.P., M.Sc.; Asst. Prof. Dr. Nualpun Sirinupong

2023 | Tesis | S2 Ilmu dan Teknologi Pangan

Citrus hystrix DC. (jeruk purut) adalah buah yang berasal dari wilayah tropis Asia Tenggara dan Cina Selatan. Buah dan daunnya terkenal sebagai bahan rempah-rempah dalam masakan Asia, tetapi kulitnya biasanya dibuang, yang menghasilkan limbah dalam jumlah besar meskipun mengandung senyawa fenolik. Senyawa fenolik sangat penting untuk menangkal reactive oxygen species (ROS), salah satu jenis radikal bebas yang mengandung oksigen yang dihasilkan secara alami selama metabolisme. Penelitian ini bertujuan untuk menyelidiki profil senyawa fenolik (kandungan fenolik total, kandungan flavonoid total, dan senyawa fenolik individu) dan aktivitas antioksidan (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, ferric reducing antioxidant power, dan oxygen radical absorbance capacity) dari ekstrak etanolik bubuk kulit jeruk purut (CHPPE). Sifat fungsionalnya dalam model biologis (viabilitas sel dan produksi intracellular ROS) juga dievaluasi menggunakan sel Caco-2 dengan stres oksidatif yang diinduksi oleh hidrogen peroksida. Untuk mengevaluasi pengaruhnya terhadap intestinal barrier, transepithelial electrical resistance (TEER) dan permeabilitas fluorescein isothiocyanate (FITC)-dekstran juga diselidiki. Kandungan fenolik total CHPPE adalah 8,13 ± 2,19 mg GAE/g CHPPE. Kandungan flavonoid total dari CHPPE adalah 108,10 ± 4,76 mg QE/g CHPPE. Kami mengidentifikasi 37 senyawa, termasuk flavonoid (26), asam fenolik (3), stilbene (2), lignan (1), dan senyawa fenolik lainnya (5). CHPPE mengandung hesperidin (16,10 ± 0,05 mg/g CHPPE), diosmin (1,95 ± 0,08 mg/g CHPPE), neohesperidin (23,83 ± 0,06 mg/g CHPPE), dan naringin (2,39 ± 0,03 mg/g CHPPE). CHPPE menunjukkan aktivitas antioksidan yang luar biasa, yaitu 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity (1876,38 ± 1275,83 µmol TE/g CHPPE), ferric reducing antioxidant power (2147,11 ± 40,73 µmol TE/g CHPPE), dan oxygen radical absorbance capacity (9370,12 ± 2164,62 µmol TE/g CHPPE), yang sebanding dengan asam askorbat. CHPPE juga secara signifikan meningkatkan viabilitas sel dan mengurangi keberadaan intracellular ROS. Efek sitoprotektif 100 µg/mL CHPPE lebih tinggi dari asam askorbat, menunjukkan kapasitas antioksidan alami yang kuat. CHPPE memiliki potensi untuk mengurangi stres oksidatif pada sel Caco-2 yang diinduksi oleh hidrogen peroksida yang menghasilkan penurunan nilai TEER dan peningkatan permeabilitas FITC-dekstran. Namun, hasil yang signifikan belum dapat dicapai pada penelitian ini. Penelitian lebih lanjut sangat diperlukan.

Citrus hystrix DC. (kaffir lime) is a fruit native to tropical Southeast Asia and Southern China. The fruits and leaves are well-known as spice ingredients in Asian dishes, but the peels are usually discarded, which produces a large amount of waste despite containing phenolic compounds. Phenolic compounds are essential to scavenge reactive oxygen species (ROS), one type of free radical that contains oxygen that is generated naturally during metabolism. This study aimed to investigate the profile of phenolic compounds (total phenolic content, total flavonoid content, and individual phenolic compounds) and antioxidant activities (2,2-diphenyl-1-picrylhydrazyl radical scavenging activity, ferric reducing antioxidant power, and oxygen radical absorbance capacity) of Citrus hystrix peel powder ethanolic extract (CHPPE). Its functional properties in a biological model (cell viability and intracellular ROS production) were also evaluated using Caco-2 cells under hydrogen peroxide-induced oxidative stress. To evaluate its effect on intestinal barrier, transepithelial electrical resistance (TEER) and fluorescein isothiocyanate (FITC)-dextran permeability were also investigated. Total phenolic content (TPC) of CHPPE was 8.13 ± 2.19 mg GAE/g CHPPE. Total flavonoid content (TFC) of CHPPE was 108.10 ± 4.76 mg QE/g CHPPE. We identified 37 compounds, including flavonoids (26), phenolic acids (3), stilbenes (2), lignans (1), and other phenolics (5). CHPPE contained hesperidin (16.10 ± 0.05 mg/g CHPPE), diosmin (1.95 ± 0.08 mg/g CHPPE), neohesperidin (23.83 ± 0.06 mg/g CHPPE), and naringin (2.39 ± 0.03 mg/g CHPPE). CHPPE exhibited remarkable antioxidant activities, which were DPPH radical scavenging activity (1876.38 ± 1275.83 µmol TE/g CHPPE), ferric reducing antioxidant power (FRAP) (2147.11 ± 40.73 µmol TE/g CHPPE), and oxygen radical absorbance capacity (ORAC) (9370.12 ± 2164.62 µmol TE/g CHPPE), comparable to the ascorbic acid. CHPPE also significantly improved cell viability and reduced the presence of intracellular ROS. The cytoprotective effect of 100 µg/mL CHPPE was higher than ascorbic acid, showing strong natural antioxidative capacity. CHPPE had the potential to attenuate oxidative stress in Caco-2 cells induced by hydrogen peroxide which caused a decrement in TEER value and an increment in FITC-dextran permeability. However, significant results could not be achieved by present study. Further research is highly required.

Kata Kunci : Citrus hystrix, Chemical constituent, Flavonoid, Cytoprotective, Intracellular ROS, Cellular permeability

  1. S2-2023-476374-abstract.pdf  
  2. S2-2023-476374-bibliography.pdf  
  3. S2-2023-476374-tableofcontent.pdf  
  4. S2-2023-476374-title.pdf