Keywords: antioxidant, antibacterial, phenolics, Philippine fruits, phytochemicals Phytochemical Screening, Total Phenolics, and Antioxidant and Antibacterial Activities of Selected Philippine Indigenous Fruits *Corresponding Author: mcrecuenco@up.edu.ph Institute of Chemistry, College of Arts and Sciences University of the Philippines Los Baños, College, Laguna 4031 Philippines Nine Philippine indigenous fruits were screened for phytochemical constituents and assessed for total phenolics and antioxidant and antibacterial activities. Qualitative tests revealed the presence of alkaloids in Canarium ovatum, cardiac glycosides in Ficus pseudopalma and C. ovatum, and terpenoids in Antidesma bunius and C. ovatum. Total phenolics were highest in Garcinia binucao and Mangifera altissima with 758 and 694 mg gallic acid equivalent (GAE) / 100 g fresh matter (FM), respectively. The DPPH radical scavenging activities ranged from 82–516 mg ascorbic acid equivalent antioxidant activity (AEAC) /100 g FM, with M. altissima having the highest value and followed by Rubus rosifolius (513 mg AEAC / 100 g FM). Ferric reducing activities were highest for M. altissima and G. binucao with 111 mg and 121 mg ascorbic acid equivalents (AAE) / 100 g FM, respectively. Phenolic and flavonoid contents were strongly and positively correlated (P < 0.05). Moreover, phenolic contents may have significant contributions to the observed radical scavenging and ferric reducing activities based on their strong positive correlations (P < 0.05). For the antibacterial activities, extracts from Citrus hystrix and R. rosifolius were the most effective against Escherichia coli (MIC 80 = 1.70 mg GAE/mL), while the F. pseudopalma extract was the most effective against Staphylococcus aureus (MIC 80 = 0.56 mg GAE / mL). Present results showed that the selected indigenous fruits could be valuable sources of phytochemicals, such as phenolics and flavonoids, with potential antioxidant and antibacterial activities. Philippine Journal of Science 149 (3-a): 697-710, October 2020 ISSN 0031 - 7683 Date Received: 19 Feb 2020 Mariam C. Recuenco*, James Russell P. De Luna, Nathalia G. Magallano, and Kevin C. Salamanez INTRODUCTION Plant-based foods, fruits and vegetables, are essential in the human diet because of their roles in sustaining life and health. They provide vital nutrients, carbohydrates, proteins, lipids, vitamins and minerals, fiber, and a wide variety of bioactive non-nutrient “phytochemicals” from plant secondary metabolism (Del Rio et al. 2013). The phenolics are one of the biggest groups of phytochemicals that include compounds such as phenolic acids, flavonoids, stilbenes, coumarins, and tannins. These compounds have molecular structures characterized by the phenol moiety of aromatic hydrocarbons with hydroxyl groups (-OH). Many studies reported the potential health benefits of dietary phenolics from cocoa, coffee, red wine, tea, berries, citrus fruits, nuts, and vegetables (Del Rio et al. 2013). Evidence from in vitro studies suggested that phenolics exhibit anti-cancer cell proliferation, anti- inflammatory, and antimicrobial activities (Del Rio et al. 697