Journal of Survey in Fisheries Sciences 10(4S) 803-809 2023 803 Preliminary study on phytonutrients constituents and the anti-oxidant potential of Gracilaria opuntia of Rameswaram Coast, India. Mr. V.S. Chandrasekaran 1,2 , Dr. M. Ganesh 3* Dr. S. Latha 4 , Dr. Adlyne Reena Asirvatham 5, Dr. M. Sivakumar 6 , Dr. K. Umasankar 7 , 1. Research Scholar, Sri Ramachandra Faculty of Pharmacy, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai. 600 116. Email: chandrasekaranvs@sriramachandra.edu.in Mobile: +91 80721 07226 2. Associate professor, Department of Pharmaceutical Biotechnology, Krishna Teja Pharmacy College, Tirupati. 517 506 Email: vschandru610@gmail.com Mobile: +91 80721 07226 3. *Professor and Head, Department of Biochemistry, Sri Ramachandra Medical College and Research Institute, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai. 600 116 Email: ganeshm@sriramachandra.edu.in Mobile: +91 98841 99902 4. Assistant Professor, Department of Pharmacognosy, Sri Ramachandra Faculty of Pharmacy, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai. 600 116 Email: latha.s@sriramachandra.edu.in Mobile: +91 99622 29445 5. Professor of Endocrinology and Consultant Endocrinologist, Sri Ramachandra Medical College and Research Institute, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai. 600 116. Email: adlyne@sriramachandra.edu.in Mobile: +91 98430 51977 6. Professor, HOD, Department of Pharmacognosy, Faculty of Pharmacy, Sree Balaji Medical College and Hospital, Bharat Institute of Science and Technology (DU), Chennai. Email: sivampharma@gmail.com Mobile: +91 9884208394 7. Professor and Head, Department of Pharmaceutics, Krishna Teja Pharmacy College, Tirupati. 517 506. Email: umasankar73@gmail.com Mobile: +91 94409 55960 *Corresponding Author; - Dr. M. Ganesh, *Professor and Head, Department of Biochemistry, Sri Ramachandra Medical College and Research Institute, Sri Ramachandra Institute of Higher Education and Research (DU), Chennai. 600 116 Email: ganeshm@sriramachandra.edu.in Mobile: +91 98841 99902 Abstract Objective: Preliminary phytonutrient and invitro evaluation of Gracilaria opuntia. Methods: Phytonutrient evaluation studied with various extracts like ethyl acetate, ethanol and purified water. The antioxidant potential was studied by DPPH, H2O2, NO and OH - assays. Results: The phytonutrient screening studies exhibits existence of various nutrient substituents. Also, a comprehensive anti-oxidant potential at 500 μg/ml in Gracilaria opuntia comparatively better than used standard. Conclusion: Thus Gracilaria opuntia can be consider for curative disease from oxidative weakening in which in-vivo studies can be evaluated in advance. Keywords: Gracilaria, Seaweed, Phytonutrient, Polyphenol compounds, Antioxidant. INTRODUCTION Natural ways stand as a golden mark to exemplify the outstanding phenomena of symbiosis. In India plants and herbal products in practice for health and medicinal purpose for several thousand years, there are nearly 1.5 million practitioners till using traditional medicine system such as Ayurveda, Siddha, Unani and Homeopathy. (Sheeta Verma et al., 2008). The main benefits of herbal medicines over allopathic are that it has least side effect, toxicity and cozy effective (Patil S Jolly et al., 2003, Anggadireja J et al., 1997, Bors W et al., 1990). Antioxidants is a substance that is