Ethanolic Extract of the Powder of Red Earthworm (Lumbricus rubellus) Obtained from Several Farmland in Bali, Indonesia, Analysis of Total Phenolic Content and Antioxidant Capacity

Background: Red earthworm (Lumbricus rubellus) has been used for centuries as an ingredient of Ayurvedic therapy and traditional Chinese medicine (TCM). The worm is used in the treatment of inflammation, hematological disorders, fever, hepatic disorders, joint pain, high blood pressure, and several other indications. L. rubellus is also bred and developed into powder in Bali, Indonesia to be used empirically in the treatment of diabetes, stroke, and joint pain. These disorders are known to be associated with inflammation and oxidative stress. Phenolics are known to act as anti-inflammatory agent. To our knowledge, there is no data on the total phenolic content and antioxidant capacity of L. rubellus obtained from Bali. Methods: Ethanolic extract of L. rubellus powder was made in The Laboratory of Division of Drug Development and Laboratory Animal, Integrated Biomedical Unit, Faculty of Medicine, Udayana University. Total phenolic content and antioxidant capacity were investigated in The Laboratory of Food Analysis, Udayana University. Total phenolic content was determined using Folin-Ciocalteu method, meanwhile antioxidant capacity was determined using DPPH method. Results: We found that ethanolic extract of L. rubellus powder had total phenolic content of 1016.31 mg/100 g gallic acid equivalent (GAE), and exhibited IC 50% of 12.33 mg/mL. Conclusion: We conclude that ethanolic extract of L. rubellus powder contains phenolic acid and shows antioxidant effect in vitro. L. rubellus powder can be potentially used as a natural antioxidant source to treat disorders associated with inflammation and oxidative stress. Keywords: Lumbricus rubellus powder, ethanolic extract, total phenolics, antioxidant capacity