INDIAN JOURNAL OF SCIENCE AND TECHNOLOGY RESEARCH ARTICLE OPEN ACCESS Received: 22.12.2020 Accepted: 31.03.2021 Published: 26.04.2021 Citation: Ma. Danica Ines Ramil , Angelica May DC. Mendoza , Rhian Jaymar D. Ramil (2021) Assessment on the Physicochemical and Phytochemical Properties, Nutritional and Heavy Metal Contents, and Antioxidant Activities of Hylocereus polyrhizus Peel from Northern Philippines. Indian Journal of Science and Technology 14(14): 1097-1104. https://doi.org/ 10.17485/IJST/v14i14.2286 ∗ Corresponding author. Tel: (+63) 927 733 9569 jaymar_1329@yahoo.com.ph Funding: None Competing Interests: None Copyright: © 2021 Ma. Danica Ines Ramil et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Published By Indian Society for Education and Environment (iSee) ISSN Print: 0974-6846 Electronic: 0974-5645 Assessment on the Physicochemical and Phytochemical Properties, Nutritional and Heavy Metal Contents, and Antioxidant Activities of Hylocereus polyrhizus Peel from Northern Philippines Ma. Danica Ines Ramil 1 , Angelica May DC. Mendoza 1 , Rhian Jaymar D. Ramil 1∗ 1 Assistant Professors, Pharmacy Department, Mariano Marcos State University, City of Batac, Ilocos Norte, 2906, Philippines. Tel.: (+63) 927 733 9569 Abstract Background/Objectives: In the Philippines, Hylocereus polyrhizus is gaining upsurge interest due to its potential health benefits. Aside from the edible fruit pulp, various products from its peel are being developed, and claimed as health boosters. Thus, this study was conducted to assess the physicochemical char- acteristics, phytochemical constituents, nutritional and heavy metal contents and antioxidant activity of the peel of H. polyrhizus. Methods/Statistical anal- ysis: Physicochemical and phytochemical screening were conducted following established protocols. Nutritional value and trace metals were measured with food analytical standard methods. Antioxidant activity was estimated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing capacity (FRC) assays. Statistical analyses were carried out for DPPH and FRC assays using Graph- Pad Prism. Findings: Results showed that H. polyrhizus peel contains alkaloids, coumarins, flavonoids, phenols, and triterpenoids. Trace amounts of arsenic (0.022 mg/kg), lead (0.887 mg/kg), cadmium (0.068 mg/kg) and chromium (0.225 mg/kg) were detected which were all within the acceptable limit set by the WHO for herbal materials. H. polyrhizus peel contained 6.72% moisture, 14.7% ash, 0.526% total fat, 0.226% saturated fat, 3.73% total sugar, 4.28% crude protein, 73.8% total carbohydrate, and 63.2% total dietary fiber. Other nutrients detected are macronutrients such as K > Ca > Mg > Na, micronutri- ents Mn > Fe, and Vitamin C. Moreover, it exhibited remarkable antioxidant activity in terms of FRC assay and DPPH assay (IC 50 = 986.8μ g/mL). The present study results showed that H. polyrhizus peel could be used as a potentially rich source of nutrients and natural antioxidants. Thus, it can be developed as an ingredient for food and health products. Novelty/Applications: The prelimi- nary data obtained provide information that could support the development of products from dragon fruit peel. The conversion of these wastes into utiliz- able natural health products would help in reducing environmental problems https://www.indjst.org/ 1097