Eksplorasi Aktivitas Antioksidan dan Antidiabetes Ekstrak dan Fraksi Terenkapsulasi Kitosan-Pektin-Natrium Tripolifosfat dari Medinilla eximia dan Medinilla speciosa

Primadevi, Susan (2026) Eksplorasi Aktivitas Antioksidan dan Antidiabetes Ekstrak dan Fraksi Terenkapsulasi Kitosan-Pektin-Natrium Tripolifosfat dari Medinilla eximia dan Medinilla speciosa. Doctoral thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Diabetes Melitus (DM) adalah penyakit yang ditandai dengan tingginya kadar glukosa dalam darah (hiperglikemia). Berdasarkan International Diabetes Federation (IDF) Diabetes Atlas 2025, pasien DM di Indonesia tahun 2024 mencapai 20,4 juta orang dan diproyeksikan akan meningkat menjadi 28,6 juta orang pada tahun 2050. Hiperglikemia menyebabkan stres oksidatif yang berperan dalam perkembangan komplikasi diabetes, sehingga senyawa yang memiliki aktivitas antioksidan juga berpotensi memberikan efek antidiabetes. Berbagai metabolit sekunder tumbuhan, seperti flavonoida, alkaloida, polifenol, fenolik, tanin dan saponin, diketahui memiliki kedua aktivitas tersebut. Salah satu tumbuhan Indonesia yang berpotensi sebagai antioksidan dan antidiabetes yaitu Medinilla eximia dan Medinilla speciosa. Obat hipoglikemik oral (OHO) memiliki beberapa keterbatasan antara lain kelarutan dan bioavailabilitas yang rendah serta tidak stabil di dalam sistem pencernaan (tidak tahan asam). Enkapsulasi merupakan pengembangan cara melapisi bahan inti (core) dengan bahan sekunder (carrier). Penelitian mengenai M. eximia dan M. speciosa masih menunjukkan beberapa kesenjangan ilmiah. Sebagian besar penelitian hanya mengevaluasi satu bagian tanaman dengan satu jenis pelarut ekstraksi, sehingga informasi mengenai variasi metabolit, aktivitas biologis, dan pengaruh polaritas pelarut terhadap komposisi senyawa bioaktif masih terbatas. Kajian potensi antidiabetes melalui penghambatan enzim α-amilase dan α-glukosidase, penerapan metabolomik berbasis LC-HRMS, serta integrasi analisis kemometrik dan analisis korelasi untuk mengaitkan profil fitokimia dengan aktivitas biologis juga belum dilaporkan secara komprehensif. Pengembangan nanosuspensi M. eximia maupun M. speciosa menggunakan sistem penyalut kitosan–pektin yang ditautsilangkan dengan natrium tripolifosfat (NaTPP) juga belum dilaporkan. Penelitian ini bertujuan untuk mengidentifikasi kandungan fitokimia, profil metabolit, aktivitas antioksidan, dan potensi antidiabetes dari ekstrak dan fraksi M. eximia dan M. speciosa, mengelompokan ekstrak dan fraksi berdasarkan kemiripan karakteristik kimia melalui analisis kemometrik, mengevaluasi hubungan antara kandungan fitokimia dan aktivitas biologis melalui uji korelasi, serta mengembangkan nanosuspensi berbasis kitosan–pektin yang ditautsilangkan dengan natrium tripolifosfat (NaTPP). Tahap penelitian meliputi remaserasi menggunakan pelarut dengan polaritas berbeda (metanol, etil asetat, diklorometana, dan n-heksana) serta campuran etanol:air dengan berbagai rasio (100:0, 75:25, 50:50, 25:75, dan 0:100), fraksinasi menggunakan sistem batch dengan polaritas pelarut yang berbeda, penapisan fitokimia, penentuan kadar flavonoida dan fenolik total, uji antioksidan (peredaman radikal DPPH dan ABTS) dan uji antidiabetes (penghambatan α-amilase dan α-glukosidase), uji korelasi Kendall’s Tau, uji kemometrik (PCA dan HCA) dan pembuatan nanosuspensi dari fraksi etil asetat. Nanosuspensi yang dihasilkan kemudian dilakukan karakterisasi gugus fungsi menggunakan Fourier Transform Infrared (FTIR), analisis ukuran partikel dengan Particle Size Analyzer (PSA), uji muatan listrik dan kestabilan nanosuspensi menggunakan Zeta Analyzer, penentuan efisiensi enkapsulasi serta stabilitas suhu (25 °C dan 4 °C) dan lama penyimpanan (0, 15, 30, 45, dan 60 hari). Hasil penelitian mengungkapkan bahwa 1) Ekstrak M. eximia variasi pelarut organik menunjukkan TFC tertinggi: buah dan daun etil asetat, ranting buah metanol; TPC tertinggi: buah, daun dan ranting buah metanol; peredaman DPPH tertinggi: buah, daun dan ranting metanol; peredaman ABTS tertinggi: buah metanol, ranting etil asetat, daun tidak ada aktivitas; penghambatan α-amilase tertinggi: buah metanol, daun dan ranting buah tidak ada aktivitas; penghambatan α-glukosidase pada substrat maltosa tertinggi: buah metanol, daun dan ranting tidak ada aktivitas, penghambatan α-glukosidase pada substrat sukrosa: buah dan daun metanol, ranting buah tidak ada aktivitas, 2) Ekstrak M. speciosa variasi pelarut organik mengindikasikan nilai TFC tertinggi: buah metanol, daun dan ranting buah diklorometana; TPC tertinggi: buah dan daun metanol, ranting buah heksana; peredaman DPPH tertinggi: buah dan daun metanol, ranting buah etil asetat; peredaman ABTS tertinggi: buah dan daun metanol, ranting buah diklorometana; penghambatan α-amilase tertinggi: buah dan ranting buah etil asetat, daun metanol; penghambatan α-glukosidase pada substrat maltosa tertinggi: buah metanol, daun dan ranting buah tidak ada aktivitas; penghambatan α-glukosidase pada substrat sukrosa tertinggi: buah dan daun metanol, ranting buah tidak ada aktivitas; 3) Ekstrak M. eximia variasi rasio etanol:air menunjukkan bahwa nilai TFC dan TPC tertinggi ditemukan pada rasio 100:0; peredaman DPPH dan ABTS tertinggi terdapat pada rasio 75:25; penghambatan α-amilase dan α-glukosidase pada substrat maltosa dan sukrosa tertinggi ditemukan pada rasio 100:0; 4) Ekstrak M. speciosa variasi rasio etanol:air memperlihatkan bahwa nilai TFC, TPC, peredaman DPPH dan ABTS, penghambatan α-amilase dan α-glukosidase pada substrat maltosa dan sukrosa tertinggi terdapat pada rasio 100:0; 5) Fraksi M. eximia mengindikasikan nilai TFC, TPC, peredaman DPPH dan ABTS, serta penghambatan α-amilase tertinggi terdapat pada fraksi etil asetat; penghambatan α-glukosidase pada substrat maltosa dan sukrosa tertinggi terdapat pada fraksi etanol; 6) Fraksi M. speciosa menghasilkan nilai TFC, peredaman ABTS dan penghambatan α-amilase tertinggi pada fraksi etil asetat; nilai TPC, peredaman DPPH dan penghambatan α-glukosidase substrat maltosa tertinggi pada fraksi etanol; tidak ada aktivitas penghambatan α-glukosidase substrat sukrosa; 7) Analisis LC-HRMS mengidentifikasi beberapa metabolit yang diperkirakan berkontribusi terhadap aktivitas antioksidan dan antidiabetes yaitu furaneol, danshensu, asam 5-hidroksiveratrik, dan 2-[4-(3-hidroksipropil)-2-metoksifenoksi]-1,3-propanediol. 8) Kandungan fenolik dan flavonoida total umumnya berkorelasi positif dengan aktivitas biologis. 9) Analisis kemometrik menunjukkan bahwa polaritas pelarut dan bagian tanaman merupakan faktor utama yang memengaruhi profil fitokimia dan bioaktivitas. 10) Fraksi etil asetat kedua tanaman memiliki penghambatan α-amilase terbaik jika dibandingkan dengan fraksi etanol, diklorometana dan n-heksana, selanjutnya berhasil diformulasikan menjadi nanosuspensi berbasis kitosan–pektin–NaTPP dan menunjukkan hasil sebagai berikut: a) M. eximia memiliki ukuran partikel sebesar 248,5 ± 5,28 nm, zeta potensial sekitar +58,97 ± 1,24 mV, dan efisiensi enkapsulasi sebesar 53,84 ± 0,25%. b) M. speciosa memiliki ukuran partikel sebesar 251,8 ± 2,89 nm, zeta potensial sekitar +58,93 ± 0,39 mV, dan efisiensi enkapsulasi sebesar 44,32 ± 0,22%. 11) Nanosuspensi (fraksi terenkapsulasi) dari M. eximia dan M. speciosa menunjukkan stabilitas yang lebih baik dibandingkan fraksi bebas dalam mempertahankan kandungan fenolik selama penyimpanan, terutama pada suhu 4°C. Penelitian selanjutnya perlu difokuskan pada isolasi dan identifikasi senyawa bioaktif yang diperkirakan berkontribusi pada aktivitas antioksidan dan antidiabetes, validasi aktivitas biologis melalui uji in vivo dan kajian mekanisme aksi, serta optimasi formulasi dan karakterisasi nanosuspensi untuk meningkatkan efisiensi enkapsulasi, stabilitas, dan bioavailabilitas sebagai dasar pengembangan M. eximia dan M. speciosa menjadi produk nutraseutikal maupun fitofarmaka.
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Diabetes Mellitus (DM) is a disease characterized by high blood glucose levels (hyperglycemia). According to the International Diabetes Federation (IDF) Diabetes Atlas 2025, the number of DM patients in Indonesia reached 20.4 million in 2024 and is projected to rise to 28.6 million by 2050. Hyperglycemia induces oxidative stress, which contributes to the development of diabetic complications; consequently, compounds possessing antioxidant activity also have the potential to exert antidiabetic effects. Various plant secondary metabolites—such as flavonoids, alkaloids, polyphenols, phenolics, tannins, and saponins—are known to exhibit both activities. Medinilla eximia and Medinilla speciosa are Indonesian plants with potential antioxidant and antidiabetic properties. Oral hypoglycemic agents (OHAs) face several limitations, including low solubility and bioavailability, as well as instability within the digestive system (acid instability). Encapsulation involves coating a core material with a secondary material (carrier). Research on M. eximia and M. speciosa still presents several scientific gaps. Most studies have evaluated only a single plant part using one type of extraction solvent; thus, information regarding metabolite variation, biological activity, and the influence of solvent polarity on bioactive compound composition remains limited. Furthermore, comprehensive studies investigating antidiabetic potential via α-amylase and α-glucosidase enzyme inhibition, the application of LC-HRMS-based metabolomics, and the integration of chemometric and correlation analyses to link phytochemical profiles with biological activities have not yet been reported. The development of M. eximia and M. speciosa nanosuspensions using a chitosan–pectin coating system cross-linked with sodium tripolyphosphate (NaTPP) also remains unreported. This study aims to identify the phytochemical content, metabolite profiles, antioxidant activity, and antidiabetic potential of extracts and fractions from M. eximia and M. speciosa; to classify these extracts and fractions based on chemical characteristic similarities using chemometric analysis; to evaluate the relationship between phytochemical content and biological activity through correlation analysis; and to develop a chitosan–pectin-based nanosuspension cross-linked with sodium tripolyphosphate (NaTPP). The research stages included remaceration using solvents of varying polarities (methanol, ethyl acetate, dichloromethane, and n-hexane) as well as ethanol-water mixtures in various ratios (100:0, 75:25, 50:50, 25:75, and 0:100); fractionation using a batch system with solvents of differing polarities; phytochemical screening; determination of total flavonoid and phenolic contents; antioxidant assays (DPPH and ABTS radical scavenging) and antidiabetic assays (α-amylase and α-glucosidase inhibition); Kendall’s Tau correlation analysis; chemometric analysis (PCA and HCA); and the preparation of a nanosuspension from the ethyl acetate fraction. The resulting nanosuspension was then characterized for functional groups using Fourier Transform Infrared (FTIR) spectroscopy and particle size using a Particle Size Analyzer (PSA); its electrical charge and nanosuspension stability was assessed using a Zeta Analyzer, and determinations were made regarding encapsulation efficiency, thermal stability (at 25°C and 4°C), and stability over storage periods (0, 15, 30, 45, and 60 days). The results revealed that: 1) M. eximia extracts from various organic solvents showed the highest TFC in ethyl acetate extracts of fruits and leaves, and methanol extracts of fruit branches; the highest TPC content was detected in the methanol extracts of the fruits, leaves, and fruit branches; the highest DPPH radical-scavenging activity was found in the methanol extracts of the fruits, leaves, and fruit branches; the highest ABTS radical-scavenging activity was observed in methanol fruit extracts and ethyl acetate fruit branches extracts (no activity in leaves); the highest α-amylase inhibition was shown in the fruits methanol extract (no activity was detected in the leaves and fruit branches); the highest α-glucosidase inhibition using maltose as the substrate was observed in the fruits methanol extract (no activity was detected in the leaves and fruit branches); the highest α-glucosidase inhibition using sucrose as a substrate was found in the methanol extracts of the fruits and leaves (no activity was detected in the fruit branches); 2) M. speciosa extracts from various organic solvents showed the highest TFC in methanol fruit extracts, dichloromethane leaves and fruit branches extracts; the highest TPC was found in the methanol extract of fruits and leaves and the n-hexane extract of fruit branches; the highest DPPH radical-scavenging activity was found in the methanol extracts of the fruits and leaves, as well as the ethyl acetate extract of the fruit branches; the highest ABTS radical-scavenging activity was detected in the methanol extracts of the fruits and leaves, as well as the dichloromethane extracts of the fruit branches; the highest α-amylase inhibition was shown in the ethyl acetate extracts of fruits and fruit branches, as well as the methanol extract of leaves; the highest α-glucosidase inhibition using maltose as the substrate was detected in the fruit methanol extract (no activity was observed in the leaves and fruits branches); the highest α-glucosidase inhibition with sucrose as the substrate was observed in the methanol extracts of fruit and leaves (no activity in the fruit branches); 3) M. eximia extracts from various ethanol: water ratios showed that the highest TFC and TPC were observed at the 100:0 ratio; the highest DPPH and ABTS radical scavenging activity were found at the 75:25 ratio; the highest α-amylase, α-glucosidase inhibition on maltose and sucrose substrate were detected at a 100:0 ratio; 4) M. speciosa extracts with varying ethanol: water ratios: the highest TFC, TPC, DPPH and ABTS scavenging activity, α-amylase and α-glucosidase inhibition on maltose and sucrose substrates were detected at a 100:0 ratio; 5) M. eximia fractions yielded the highest TFC, TPC, DPPH and ABTS radical scavenging activity, as well as α-amylase inhibition, were observed in the ethyl acetate fractions; the highest α-glucosidase inhibition on maltose and sucrose substrates were found in the ethanol fractions; 6) M. speciosa fractions yielded the highest TFC, ABTS radical scavenging activity and α-amylase inhibition values in the ethyl acetate fractions; the highest TPC, DPPH radical scavenging activity and α-glucosidase inhibition on maltose substrate were detected in the ethanol; no α-glucosidase inhibition activity was observed with the sucrose substrate; 7) LC-HRMS analysis identified several metabolites—furaneol, danshensu, 5-hydroxyveratric acid, and 2-[4-(3-hydroxypropyl)-2-methoxyphenoxy]-1,3-propanediol—presumed to contribute to antioxidant and antidiabetic activities. 8) Total phenolic and flavonoid contents generally showed a positive correlation with biological activities. 9) Chemometric analysis indicated that solvent polarity and plant part were the primary factors influencing phytochemical profiles and bioactivity. 10) The ethyl acetate fractions of both plants exhibited the highest α-amylase inhibition compared to the ethanol, dichloromethane, and n-hexane fractions; these were subsequently formulated into chitosan–pectin–NaTPP-based nanosuspensions, yielding the following results: a) M. eximia showed a particle size of 248.5 ± 5.28 nm, a zeta potential of approximately +58.97 ± 1.24 mV, and an encapsulation efficiency of 53.84 ± 0.25%. b) M. speciosa showed a particle size of 251.8 ± 2.89 nm, a zeta potential of approximately +58.93 ± 0.39 mV, and an encapsulation efficiency of 44.32 ± 0.22%. 11) The nanosuspensions (encapsulated fractions) of M. eximia and M. speciosa demonstrated superior stability compared to the free fractions in retaining phenolic content during storage, particularly at 4°C. Future research should focus on the isolation and identification of bioactive compounds presumed to contribute to antioxidant and antidiabetic activities; the validation of biological activity through in vivo assays and studies on mechanisms of action; and the optimization of formulation and characterization of nanosuspensions to enhance encapsulation efficiency, stability, and bioavailability, thereby laying the groundwork for developing M. eximia and M. speciosa into nutraceutical or phytopharmaceutical products.

Item Type:	Thesis (Doctoral)
Uncontrolled Keywords:	Medinilla eximia, Medinilla speciosa, antioksidan, antidiabetes, nanosuspensi, Medinilla eximia, Medinilla speciosa, antioxidant, antidiabetic, nanosuspension
Subjects:	Q Science > QD Chemistry > QD251.2 Chemistry, Organic. Biochemistry Q Science > QD Chemistry > QD471 Chemical compounds - Structure and formulas
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Chemistry > 47001-(S3) PhD Thesis
Depositing User:	Susan Primadevi
Date Deposited:	05 Aug 2026 06:51
Last Modified:	05 Aug 2026 06:51
URI:	http://repository.its.ac.id/id/eprint/144064

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