ANTIOXIDANT MOLECULES IN THE SEA ANEMONE ANTHOPLEURA CASCAIA AND THEIR APPLICATION IN ALZHEIMER'S DISEASE

Introduction: One of the main causes of Alzheimer’s disease (AD) is the accumulation of β-amyloid peptide in brain, leading to several consequences for neurons, including oxidative stress. To counteract oxidative stress, new antioxidants have been studied; however, few are able to cross the blood–brain barrier or demonstrate effectiveness. This study aimed to obtain new antioxidants from the sea anemone Anthopleura cascaia, whose venom has the potential to inhibit neuronal death caused by Aβ42. Methods: A. cascaia was collected in São Sebastião/SP/Brazil, and its venom was extracted through chemical stimulation. The venom was subsequently fractionated based on its antioxidant activity and assessed by DPPH and PFRAP tests. The first fractionation step was a solid-phase extraction (SPE, C18 cartridge), with elution at 0,25, 50, 75 and 100% acetonitrile/0.1% trifluoroacetic acid (TFA). A second fractionation was conducted using HPLC with a C18 column and a 0-100% acetonitrile/0.1% TFA gradient, followed by a third fractionation using an HILIC column. Thepurified active molecule was analyzed by mass spectrometry and incubated with differentiated-SH-SY5Y neurons, pre-exposed to Aβ42 for 48 h. Cell viability was assessed using the LDH test. Results: The 0% SPE fraction and the first peak of C18-HPLC exhibited antioxidant activity in both tests. Due to peak impurities, a third fractionation step was performed, yielding six fractions, and one of them demonstrated 40% and 50% antioxidant activity in the DPPH and PFRAP tests, respectively. Mass spectrometry analysis confirmed high purity and an ion at 232.943 m/z, with no matches in natural products databases. Furthermore, this molecule successfully inhibited neuronal death induced by Aβ42, with LDH values comparable to the control. Conclusion: A novel antioxidant molecule with neuroprotective potential was successfully isolated from a sea anemone. This discovery could contribute to the development of a prototype for a new AD treatment by targeting a key mechanism associated with the disease.