Identifikasi Senyawa Aktif dan Aktivitas Antidiabetes Ekstrak Daun dan Kulit Pohon (Toona sinensis) secara In Silico dan In Vitro

Abstract

Ekstrak surian (Toona sinensis) mengonfirmasi potensi antidiabetesnya sebagai inhibitor a-glukosidase. Ekstrak etanol 70% kulit surian dilaporkan penelitian terdahulu memiliki aktivitas inhibisi a-glukosidase terbaik dibanding pelarut lain. Penelitian lain melaporkan daun dan kulit pohon surian yang diekstraksi menggunakan etanol 70% memiliki aktivitas inhibisi terhadap enzim yang sama. Ekstrak yang sama juga dilaporkan pada penelitian lain mampu menurunkan gula darah pada tikus diabetes. Akan tetapi, perbedaan usia dan lokasi pohon mempengaruhi kandungan metabolitnya. Penelitian ini bertujuan mengidentifikasi kandungan senyawa aktif, prediksi senyawa yang berperan dalam penghambatan, serta aktivitas inhibisi a-glukosidase dari ekstrak etanol 70% daun dan kulit pohon surian berusia 25 tahun asal Indonesia. Metode maserasi etanol 70% digunakan pada penelitian ini. Kedua ekstrak diukur aktivitas inhibisinya terhadap a-glukosidase in vitro secara spektrometri. Kandungan senyawa dalam kedua ekstrak lalu dianalisis menggunakan LC-HRMS. Senyawa yang teridentifikasi kemudian dimodelkan inhibisinya terhadap a-glukosidase dan diprediksi sifat bioavailabilitas dan toksisitasnya untuk menentukan senyawa terbaiknya. Hasil analisis LC-HRMS menunjukkan kulit batang lebih kaya akan metabolit sekunder bioaktif dibandingkan ekstrak daun, yang sejalan dengan hasil IC50. Hasil penelusuran dengan online database terdapat 16 senyawa penciri pada ekstrak surian. Simulasi penambatan molekuler mengidentifikasi delapan senyawa flavonoid sebagai kandidat potensial, dengan Dihydroxymandelic acid dan Quercetin sebagai perwakilan setiap sampel yang menunjukkan afinitas ikatan tertinggi melalui interaksi kunci, termasuk penguncian residu katalitik ASP 443. Kedua senyawa lolos aturan Lipinski serta lolos prediksi toksisitas menunjukkan ligan yang paling potensial memiliki bioavailabilitas oral yang tinggi, menyoroti bahwa pengembangan obat harus menyeimbangkan efikasi ikatan yang kuat dengan sifat penyerapan yang baik dan bersifat tidak toksik. Kedua ekstrak etanol 70% menunjukkan aktivitas inhibisi a-glukosidase dengan nilai IC50 ekstrak kulit (200,84 ppm) lebih rendah dibanding daun (254,41 ppm) menandakan inhibisi ekstrak kulit lebih kuat, walaupun tidak sebaik akarbosa (0,33 ppm). Kesimpulan penelitian ini yaitu kedua ekstrak etanol 70% daun dan kulit surian memiliki kandungan metabolit yang teridentifikasi oleh analisis LC-HRMS dengan 16 senyawa penciri, hasil prediksi penambatan molekuler sehingga memiliki inhibisi a-glukosidase.

Surian extract confirms its antidiabetic potential as an a-glucosidase inhibitor. Ethanol extract of 70% of sunskin was reported in previous studies to have the best a-glucosidase inhibition activity compared to other solvents. Another study reported that the leaves and bark of surian trees extracted using 70% ethanol had the same inhibitory activity against the enzyme. The same extract was also reported in another study to be able to lower blood sugar in diabetic rats. However, the difference in the age and location of the tree affects its metabolite content. This study aims to identify the content of active compounds, prediction of compounds that play a role in inhibition, and a-glucosidase inhibition activity from ethanol extract of 70% of the leaves and bark of a 25 years old surian tree from Indonesia. The 70% ethanol maceration method was used in this study. Both extracts were measured for their inhibition activity against a-glucosidase in vitro spectrometrically. The compound content in both extracts was then analyzed using LC-HRMS. The identified compounds were then modeled for their inhibition to a-glucosidase and predicted their bioavailability and toxicity properties to determine the best compound. The results of the LC-HRMS analysis showed that the bark of the stem was richer in bioactive secondary metabolites than leaf extract, which was in line with the results of IC50. The results of a search with an online database found 16 characteristic compounds in surian extract. Molecular tethering simulations identified eight flavonoid compounds as potential candidates, with Dihydroxymandelic acid and Quercetin as representatives of each sample showing the highest bond affinity through key interactions, including ASP 443 catalytic residue locking. Both compounds passed Lipinski's rules and passed toxicity predictions indicating the most potent ligands have high oral bioavailability, highlighting that drug development must balance strong bond efficacy with good absorption properties and non-toxicity. Both ethanol extracts showed 70% a-glucosidase inhibition activity with an IC50 value of skin extract (200.84 ppm) lower than leaves (254.41 ppm), indicating stronger skin extract inhibition, although not as good as acarbone (0.33 ppm). The conclusion of this study is that both ethanol extracts of 70% leaves and sunflower bark have metabolite content identified by LC-HRMS analysis with 16 characterizing compounds, the result of predicting molecular tethering so that it has a-glucosidase inhibition.