Disertasi

Aktivitas Hepatoprotektor Gambir (Uncaria gambir (Hunter) Roxb.) dalam Menghambat Pembentukan Kolagen dengan Menekan TIMP-1 (tissue inhibitor of metalloproteinase-1) in vivo. = Hepatoprotector activity of gambir (Uncaria gambir (Hunter) Roxb.) in inhibiting collagen formation by suppressing TIMP-1 (tissue inhibitor of metalloproteinase-1)) expression in vivo.

Prevalensi penyakit hati meningkat sepanjang tahun. Data RISKESDAS 2013 menyatakan terjadi peningkatan prevalensi hepatitis pada semua umur dari 0,6% pada 2007 menjadi 1,2% pada 2013. Sirosis hati menduduki peringkat ke-7 penyebab kematian di negara-negara barat dan hingga saat ini belum teratasi dengan baik. Salah satu penyebab cedera hati adalah stres oksidatif yang perlu diteliti lebih lanjut dengan memanfaatkan antioksidan alami. Gambir (Uncaria gambir (Hunter) Roxb.) adalah tanaman spesifik lokasi Indonesia dengan kandungan utama flavonoid (+)-katekin terbukti mempunyai aktivitas antioksidan. Penelitian ini bertujuan untuk membuktikan bahwa gambir mampu bekerja sebagai hepatoprotektor dengan menghambat pembentukan fibrosis hati. Sampel uji terpilih (EG) dilakukan dengan penapisan aktivitas antiperoksidasi lipid terhadap 5 jenis sampel (ekstrak EtOH96% getah gambir, ekstrak EtOH50% getah gambir, getah gambir, ekstrak EtOH96% daun, ekstrak EtOH50% daun gambir). Pengujian antifibrosis in vivo dilakukan dengan dua pendekatan yaitu fibrostatis dan fibrolisis pada tikus jantan SD yang diinduksi 0,1 mL/kg.BB CCl4 2x seminggu selama 6 minggu p.o. dalam 8 kelompok, 5 ekor per kelompok. EG diberikan pada dosis 65, 131 dan 262 mg/kg.BB p.o. Pada uji fibrostatis, EG diberikan 1 minggu sebelum dan 6 minggu bersamaan pemberian CCl4. Pada fibrolisis, diberikan 4 minggu terakhir pemberian CCl4 selama 6 minggu bersama CCl4. Parameter yang diukur adalah tingkat cedera hati (ALAT, ASAT, MDA hati), fungsi hati (ALP, bilirubin total dan albumin), derajat fibrosis (persentase luas fibrosis, jumlah lobulus/mm2, ekspresi TIMP-1 dan collagen I, luas perlemakan secara histopatologi). Pembanding positif digunakan Polyphenon60 dosis 125 mg/kg.BB. Hasil penapisan menunjukkan bahwa EG adalah ekstrak EtOH96% getah gambir (IC50 = 11,58 ppm). Induksi CCl4 mampu meningkatkan luas fibrosis hati 9x normal in vivo. Pengujian fibrostatis, dosis EG 65 mg/kg.BB mampu menekan luas fibrosis hati tertinggi sebesar 28%, setara dengan K(+) (p=0,773), tidak berbeda bermakna dibanding K(-) (p=0,724) dan mampu menekan ekspresi TIMP-1 dan collagen I secara bermakna dibanding K(-) (p < 0,05). Pada uji fibrolisis, EG dosis 262 mg/kg.BB mampu menekan persentase luas fibrosis hati sebesar 72% yang berbeda bermakna dibanding K(-) (p < 0,05), lebih aktif secara bermakna dibanding K(+) (p < 0,05), menghambat secara bermakna ekspresi TIMP-1 dan collagen I dibanding K(-) (p < 0,05). Efektivitas antifibrosis EG pada kedua metode uji berkorelasi positif dengan parameter cedera hati, fungsi hati, dan derajat fibrosis hati. Kesimpulan penelitian ini adalah bahwa aktivitas antioksidan EG terbukti mampu menekan perkembangan fibrosis hati yaitu aktivitas fibrolisis pada dosis 262 mg/kg.BB lebih baik dibanding fibrostatis pada dosis 65 mg/kg.BB karena mampu menekan ekspresi TIMP-1 dan collagen I serta biokimia darah terkait fungsi dan cedera hati, sehingga EG berpotensi untuk dikembangkan sebagai sediaan antifibrosis dengan pendekatan fibrolisis.
Kata kunci. Antiperoksidasi lipid, collagen I, fibrolisis, fibrostatis, gambir (Uncaria gambir (Hunter) Roxb.), TIMP (tissue inhibitors of metalloproteinase)-1.



The prevalence of liver disease has increased throughout the year. RISKESDAS 2013 stated that there was a double increase in 5 years of the hepatitis prevalence for all ages from 0.6% in 2007 to 1.2% in 2013. Liver cirrhosis is ranked as seventh leading cause of death in western countries and has not been resolved satisfactorily until now. Oxidative stress is one of the causes of liver injury that requires the further treatment using natural antioxidant. Gambir (Uncaria gambir (Hunter) Roxb.), an Indonesian native plant that contain (+)-catechin demonstrated an antioxidant activity. Therefore, the purpose of this research was to prove that gambir has a hepatoprotective activity by supressing the formation of liver fibrosis. To determine the most active gambir extract (EG) for antifibrotic test in vivo was conducted by antilipid peroxidase activity in vitro toward five kinds of gambir extracts (EtOH96% gambir gum, EtOH50% gambir gum, gambir gum, EtOH96% gambir leaf and EtOH50% gambir leaf, respectively). Antifibrosis activities in vivo were conducted with two methods, namely, fibrostatis and fibrolisis on 0.1 mL/kg.BB CCl4 twice a week for 6 weeks p.o. induced eight groups SD male rats with 5 rats each group. EG was given at three level doses, i.e. 65, 131 and 262 mg/kg.BB p.o. In the fibrostatis method, EG was given for 1 week before and 6 weeks of concurrent CCl4 administration. In fibrolisis experiment, EG was delivered at the last 4 weeks for 6 weeks CCl4 administration simultaneously. The tested parameters were the biomarkers of liver injury (ALAT, ASAT, MDA liver), liver function (ALP, total bilirubin and albumin), the degree of liver fibrosis (fibrosis area, the number of lobules/mm2, TIMP-1 and collagen I expression, fatty change histopathologically). Polyphenon60 was used as a positive control at the dose of 125 mg/kg.BB. The results showed that the most active extract (EG) was EtOH96% gambir extract (IC50=11.58 ppm). CCl4 induction could increase 9 fold normal liver fibrosis area. In the fibrostatis method, 65 mg/kg.BB was the optimum dose that capable to suppress liver fibrosis by 28% of K(-) in which it was an equivalent to K(+) (p=0,773), not different to K(-) (p=0,724) and could suppress the expression of TIMP-1 and collagen I (p < 0.05), significantly. In the fibrolysis experiment, the optimum dose was at 262 mg/kg.BB that exhibited 72% reduce of liver fibrosis compared to K(-), significantly higher than K(+) (p < 0.05), different to K(-) (p < 0.05) and capable of inhibiting the expression of TIMP-1 and collagen I (p < 0.05). The antifibrosis efficacy of EG in both experiments were also positively correlated with the biomarker of liver function, liver injuries, and degree of fibrosis. From this experiments could be concluded that the antioxidant properties of EG was proven to suppress the development of liver fibrosis in which the fibrolysis activity at the dose of 262 mg/kg.BB was better than the fibrostatis one at 65 mg/kg.BB because it was able to suppress the expression of TIMP-1, collagen I and biomarker of liver function and liver injury as well. EG has the potential to be developed as an antifibrosis agent with fibrolisis approach.
Keywords: Lipid peroxidation, collagen I, fibrolysis, fibrostatis, gambir (Uncaria gambir (Hunter) Roxb.), TIMP-1 (tissue inhibitors of metalloproteinase-1).