BIODIVERSITAS ISSN: 1412-033X Volume 24, Number 6, June 2023 E-ISSN: 2085-4722 Pages: 3481-3487 DOI: 10.13057/biodiv/d240645 Screening and evaluation of antidiabetic activities of endophytic fungi associated with Etlingera elatior LAITA NURJANNAH 1,2, , AZMI AZHARI 2 , ASRI PENI WULANDARI 3 , SUSENO AMIN 4 , UNANG SUPRATMAN 5,6, 1 Graduate School of Biotechnology, Universitas Padjadjaran. Jl. Dipati Ukur No. 35, Bandung 40132, West Java, Indonesia. Tel.: +62-22-2504970,  email: nurjannahlaita@gmail.com 2 Department of Chemistry Education, Faculty of Tarbiyah and Teacher Training, Institut Agama Islam Negeri Syekh Nurjati. Jl. Perjuangan By Pass Sunyaragi, Cirebon 45132, West Java, Indonesia 3 Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran. Jl. Raya Bandung-Sumedang Km. 21, Jatinangor, Sumedang 45363, West Java, Indonesia 4 Department of Agrotechnology, Faculty of Agriculture, Universitas Padjadjaran. Jl. Raya Bandung Sumedang KM 21, Jatinangor, Sumedang 45363, West Java, Indonesia 5 Department of Chemistry, Faculty of Mathematics and Natural Sciences, Universitas Padjadjaran. Jl. Raya Bandung-Sumedang Km. 21, Jatinangor, Sumedang 45363, West Java, Indonesia 6 Central Laboratory, Universitas Padjadjaran. Jl. Raya Bandung-Sumedang Km. 21, Jatinangor, Sumedang 45363, West Java, Indonesia. Tel.: +62-818-0212-2547,  email: unang.supratman@unpad.ac.id Manuscript received: 31 March 2023. Revision accepted: 25 June 2023. Abstract. Nurjannah L, Azhari A, Wulandari AP, Amin S, Supratman U. 2023. Screening and evaluation of antidiabetic activities of endophytic fungi associated with Etlingera elatior. Biodiversitas 24: 3481-3487. Etlingera elatior (Jack) R.M.Sm. has been well- documented to have antioxidant and antidiabetic properties. Among all medical conditions worldwide, diabetes mellitus is one of the leading causes of death. Therefore, research on the discovery of antidiabetic medicines inhibitory to α-glucosidase (an enzyme for degrading complex dietary carbohydrates into sugar in the digestive process) is urgently needed. This study aims to isolate and evaluate the potential of the fermentation culture of endophytic fungi associated with E. elatior to inhibit the activity of α-glucosidase. The endophytic fungi were isolated from various parts of E. elatior. A total of 29 isolates were successfully isolated from the plant's roots, stems, leaves, and flowers. The endophytic fungi were tested for their ability to inhibit α-glucosidase activity in bioassays. Among those isolates, 8 were inhibitory to such an enzyme, and 2 showed the highest inhibitory activities. Morphotype and molecular identification of those isolates, using their Internal Transcribed Spacer (ITS) regions of ribosomal DNA (rDNA), identified them as Daldinia eschscholtzii isolate CFL 7 and Hypoxylon trugodes voucher YMJ 57, with IC50 values of 738 μg/mL and 825 μg/mL, respectively. That indicates that they are potentially used in preventing or treating diabetic mellitus. Keywords: α-glucosidase, antidiabetic, endophytic fungi, Etlingera elatior Abbreviations: ITS: Internal Transcribed Spacer, rDNA: ribosomal DNA INTRODUCTION Diabetes is one of the many major risks of mortality in the world. According to the International Diabetes Federation (IDF 2019), 1 in 11 adults aged 20-79 worldwide suffered from diabetes (around 463 million). However, 50% of them (232 million) did not know they had diabetes. Recently, Indonesia has been on the 6 th rank in the world after China, India, the United States, Brazil, and Mexico, in terms of people aged 20-79 years suffering from diabetes (around 10.3 million people) (Health Research and Development Agency 2019). Diabetes could be prevented or controlled by managing monosaccharide absorption or controlling the activities of carbohydrate-degrading enzymes (Alagesan et al. 2012). Two principal digestive enzymes, α-amylase and α- glucosidase are responsible for degrading complex dietary carbohydrates into sugar in the digestive tract (Lee et al. 2013). In recent years, plants have been utilized as traditional medicines to treat patients with various types of diabetes, such as retinopathy, peripheral neuropathy, diabetes, etc. The application of endophytes, however, has not been extensively explored for antidiabetic agents (Franco et al. 2002). Exploration of microbe valuable bioactive compounds is relatively easier than plant bioactive compounds and tends to be inexpensive (Nair et al. 2013). Different types of plants are known to produce α-amylase and α-glucosidase inhibitors, but reports on such inhibitors from endophytic microorganisms are limited (Mun'im et al. 2013). The use of α-glucosidase inhibitors in the therapy of diabetic patients is safer than that of other oral antidiabetic drugs. Therefore, recent research has been focused on finding sources of α-glucosidase inhibitors. According to Kaur et al. (2018), endophytic fungi have great potential as a source of α-glucosidase inhibitory compounds. Etlingera elatior (Jack) R.M.Sm. belongs to the Zingiberaceae family and has been used as an antidiabetic