α-Amylase and α-Glucosidase Inhibitory Activities of Endophytic Fungal Extracts Isolated from Smallanthus sonchifolius (Yacon) Leaves

Khiky Dwinatrana, Nofrizal Nofrizal, Frisca Rachmadhany, Rustini Rustini

Abstract

Endophytic fungi are recognized as potential sources of bioactive metabolites with inhibitory activity against carbohydrate-hydrolyzing enzymes. This study evaluated the α-amylase and α-glucosidase inhibitory activities of endophytic fungal extracts isolated from Smallanthus sonchifolius (yacon) leaves and molecularly characterized the selected isolate based on the internal transcribed spacer (ITS) region. Five previously isolated endophytic fungi (DY1–DY5) were cultivated on rice medium, extracted with ethyl acetate, and evaluated for α-amylase and α-glucosidase inhibitory activities using the 3,5-dinitrosalicylic acid and p-nitrophenyl-α-D-glucopyranoside methods, respectively, with acarbose as the reference inhibitor. IC₅₀ values were determined by probit regression, and differences among extracts were evaluated using analysis of variance with appropriate post-hoc tests. All fungal extracts exhibited inhibitory activity against both enzymes, with significant differences among samples (p < 0.001). DY5 showed the strongest α-amylase inhibition with an IC₅₀ of 26.35 ± 0.15 µg/mL, while DY1 showed the strongest α-glucosidase inhibition with an IC₅₀ of 12.94 ± 0.19 µg/mL. Under the present assay conditions, these values were lower than those of acarbose, which showed IC₅₀ values of 33.45 ± 1.72 µg/mL and 110.70 ± 3.48 µg/mL against α-amylase and α-glucosidase, respectively. ITS sequence analysis identified DY1 as Aspergillus tamarii, showing 99.65% sequence identity and 100% query coverage with A. tamarii sequences in GenBank. This taxonomic placement was further supported by phylogenetic analysis. These findings demonstrate distinct enzyme-inhibitory profiles among yacon-associated endophytic fungi and highlight DY1 and DY5 as promising candidates for further investigation of fungal metabolites responsible for α-glucosidase and α-amylase inhibition, respectively.

Keywords

Aspergillus tamarii; Antidiabetic; Endophytic fungi; Smallanthus sonchifolius; α-amylase; α-glucosidase

References

Agrawal, S., Samanta, S., & Deshmukh, S. K. (2022). The antidiabetic potential of endophytic fungi: Future prospects as therapeutic agents. Biotechnology and Applied Biochemistry, 69(3), 1159–1165.

Altschul, S. F., Gish, W., Miller, W., Myers, E. W., & Lipman, D. J. (1990). Basic local alignment search tool. Journal of Molecular Biology, 215(3), 403–410. https://doi.org/10.1016/S0022-2836(05)80360-2

Brown, D. W., Butchko, R. A., Busman, M., & Proctor, R. H. (2012). Identification of gene clusters associated with fusaric acid, fusarin, and perithecial pigment production in Fusarium verticillioides. Fungal Genetics and Biology, 49(7), 521–532.

Dos Reis, J. B. A., Lorenzi, A. S., & do Vale, H. M. M. (2022). Methods used for the study of endophytic fungi: A review on methodologies and challenges, and associated tips. Archives of Microbiology, 204(11), 675.

Du, C., & Zhao, Z. (2025). Characteristic analysis of adverse reactions to natural and synthetic alpha-glucosidase inhibitors: A descriptive analysis using World Health Organisation-VigiAccess. Journal of Chromatography B, 124800.

Dwinatrana, K., Ferdian, A., Rachmadhany, F., Aprodita, R. D., Aprilia, P., & Febrina, D. D. (2026). Antibacterial, antioxidant, and cytotoxic potential of an endophytic Fusarium verticillioides from yacon (Smallanthus sonchifolius) leaves. SITAWA: Jurnal Farmasi Sains dan Obat Tradisional, 5(2), 251–258.

Edgar, R. C. (2004). MUSCLE: Multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research, 32(5), 1792–1797. https://doi.org/10.1093/nar/gkh340

Felsenstein, J. (1985). Confidence limits on phylogenies: An approach using the bootstrap. Evolution, 39(4), 783–791. https://doi.org/10.1111/j.1558-5646.1985.tb00420.x

Gupta, A., Meshram, V., Gupta, M., Goyal, S., Qureshi, K. A., Jaremko, M., & Shukla, K. K. (2023). Fungal endophytes: Microfactories of novel bioactive compounds with therapeutic interventions: A comprehensive review on the biotechnological developments in the field of fungal endophytic biology over the last decade. Biomolecules, 13(7), 1038.

Goswami, D., Borah, S. N., Lahkar, J., Handique, P. J., & Deka, S. (2015). Antifungal properties of rhamnolipid produced by Pseudomonas aeruginosa DS9 against Colletotrichum falcatum. Journal of basic microbiology, 55(11), 1265-1274.

Handayani, D., Dwinatrana, K., & Rustini, R. (2022). Antibacterial compound from marine sponge derived fungus Aspergillus sydowii DC08. Rasayan J. Chem, 15, 2485-2492.

Honoré, S. M., Genta, S. B., & Sánchez, S. S. (2015). Smallanthus sonchifolius (Yacon) leaves: An emerging source of compounds for diabetes management. Journal of Research in Biology, 5(A), 21–42.

Ilic, J., Cosic, J., Vrandecic, K., Dugalic, K., Pranjic, A., & Martin, J. (2017). Influence of endophytic fungi isolated from symptomless weeds on cherry plants. Mycosphere, 8(1), 18–30.

Kashtoh, H., & Baek, K. H. (2023). New insights into the latest advancement in α-amylase inhibitors of plant origin with anti-diabetic effects. Plants, 12(16), 2944.

Kimura, M. (1980). A simple method for estimating evolutionary rates of base substitutions through comparative studies of nucleotide sequences. Journal of Molecular Evolution, 16, 111–120. https://doi.org/10.1007/BF01731581

Kjer, J., Debbab, A., Aly, A. H., & Proksch, P. (2010). Methods for isolation of marine-derived endophytic fungi and their bioactive secondary products. Nature Protocols, 5(3), 479–490.

Lee, K. M., Lee, G. S., Shim, H., Kim, S. H., Nam, S. H., & Kang, T. J. (2012). Inhibitory effect of the culture broth extract of Aspergillus tamarii on nitric oxide production and its antioxidative activity. International Journal of Industrial Entomology, 25(2), 153–157.

Ma, Y. M., Liang, X. A., Zhang, H. C., & Liu, R. (2016). Cytotoxic and antibiotic cyclic pentapeptide from an endophytic Aspergillus tamarii of Ficus carica. Journal of Agricultural and Food Chemistry, 64(19), 3789–3793.

Miller, G. L. (1959). Use of dinitrosalicylic acid reagent for determination of reducing sugar. Analytical Chemistry, 31(3), 426–428. https://doi.org/10.1021/ac60147a030

Oboh, G., Agunloye, O. M., Adefegha, S. A., Akinyemi, A. J., & Ademiluyi, A. O. (2014). Caffeic and chlorogenic acids inhibit key enzymes linked to type 2 diabetes (in vitro): A comparative study. Journal of Basic and Clinical Physiology and Pharmacology, 26(2), 165–170. https://doi.org/10.1515/jbcpp-2013-0141

Proença, C., Ribeiro, D., Freitas, M., & Fernandes, E. (2021). Flavonoids as potential agents in the management of type 2 diabetes through the modulation of α-amylase and α-glucosidase activity: A review. Critical Reviews in Food Science and Nutrition, 62(12), 3137–3207. https://doi.org/10.1080/10408398.2020.1862755

Rawal, P., Pandey, B., Yadav, R. K., & Panta, S. (2025). Antioxidant, alpha-amylase inhibitory and hypoglycemic activity of Smallanthus sonchifolius leaves from Nepal: An integrated in vitro, in vivo, and in silico approach. Food Science & Nutrition, 13(1), e4672.

Russo, D., Valentão, P., Andrade, P. B., Fernandez, E. C., & Milella, L. (2015). Evaluation of antioxidant, antidiabetic and anticholinesterase activities of Smallanthus sonchifolius landraces and correlation with their phytochemical profiles. International Journal of Molecular Sciences, 16(8), 17696–17718.

Schoch, C. L., Seifert, K. A., Huhndorf, S., Robert, V., Spouge, J. L., Levesque, C. A., & Chen, W. (2012). Nuclear ribosomal internal transcribed spacer (ITS) region as a universal DNA barcode marker for fungi. Proceedings of the National Academy of Sciences of the United States of America, 109(16), 6241–6246. https://doi.org/10.1073/pnas.1117018109

Syafni, N., Fakhriadi, A., Nofrizal, Ismed, F., & Putra, D. P. (2023). Inhibition of edible plant torch ginger (Etlingera elatior (Jack) R.M. Sm.) against α-glucosidase and α-amylase. Jurnal Sains Farmasi & Klinis, 10(3), 348–352. https://doi.org/10.25077/jsfk.10.3.348-352.2023

Ton That Huu, D., Phuong, H. T., Diem Tran, P. T., Souvannalath, B., Trung, H. L., Ho, D. V., & Viet, C. L. C. (2022). Secondary metabolites from the grasshopper-derived entomopathogenic fungus Aspergillus tamarii NL3 and their biological activities. Natural Product Communications, 17(12), 1934578X221141548.

Waqar, S., Bhat, A. A., & Khan, A. A. (2023). Endophytic fungi: Unravelling plant-endophyte interaction and the multifaceted role of fungal endophytes in stress amelioration. Plant Physiology and Biochemistry, 206, 108174. https://doi.org/10.1016/j.plaphy.2023.108174

Wang, X., Li, J., Shang, J., Bai, J., Wu, K., Liu, J., ... & Shao, L. (2022). Metabolites extracted from microorganisms as potential inhibitors of glycosidases (α-glucosidase and α-amylase): A review. Frontiers in Microbiology, 13, 1050869.

Zhang, H. C., Ma, Y. M., Liu, R., & Zhou, F. (2012). Endophytic fungus Aspergillus tamarii from Ficus carica L., a new source of indolyl diketopiperazines. Biochemical Systematics and Ecology, 45, 31–33.

DOI: https://doi.org/10.20961/jpscr.v11i2.111997

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