Indonesia has the world's country second largest forest biodiversity, with 28,000 plant species, of which 2,500 species, including Castanopsis costata, commonly known as "Cep-cepan", are used as medicine. 9-10 C. costata belongs to the Fagaceae family and has been known to exhibit therapeutic activities, for instance, anti-fever, digestive issue alleviation, and analgesic properties. 11 According to previous studies, C. costata exhibits numerous biological properties, including antioxidant activity, 12 antiinflammatory activity, 13 and antimalaria activity. 10 Furthermore, in North Sumatra, the plant is frequently used to treat diabetes, however, there are no studies confirming this practice. Therefore, this study aims to evaluate the anti-diabetic activity of the extract and fractions of C. costata leaves.
MATERIALS AND METHODS
Plant material collection and preparationAbout 10 kg of fresh C. costata leaves were collected in Pancur Batu Districts, North Sumatra, and transported to the Central Laboratory, Buana Perjuangan Karawang University for cleaning, air drying, milling, and extraction. The Herbarium Unit of the Department of Biology, Faculty of Mathematics and Science, Universitas Padjadjaran later recognized the plant as C. costata (Code: 219/HB/04/2017).
Reagents and instrumentsThis study induced diabetes in Swiss albino mice using alloxan monohydrate (Sigma Chemical