Exploring the Neuroprotective Potential of Desmodium Species: Insights into Radical Scavenging Capacity and Mechanisms against 6-OHDA-Induced Neurotoxicity

In this study, we collected seven prevalent Taiwanese plants, including three species with synonymous characteristics, in order to assess their antioxidant phytoconstituents and radical scavenging capacities. Additionally, we compared their inhibitory activities on monoamine oxidase (MAO) and 6-hydroxydopamine (6-OHDA) auto-oxidation. Subsequently, we evaluated the neuroprotective potential of on 6-OHDA-induced nerve damage in SH-SY5Y cells and delved into the underlying neuroprotective mechanisms. Among the seven species, exhibited the most robust ABTS radical scavenging capacity and relative reducing power; correspondingly, it had the highest total phenolic and phenylpropanoid contents. Meanwhile, showcased the best hydrogen peroxide scavenging capacity and, notably, demonstrated remarkable prowess in DPPH radical and superoxide scavenging capacity, along with selective inhibitory activity against MAO-B. Of the aforementioned species, emerged as the frontrunner in inhibiting 6-OHDA auto-oxidation and conferring neuroprotection against 6-OHDA-induced neuronal damage in the SH-SY5Y cells. Furthermore, effectively mitigated the increase in intracellular ROS and MDA levels through restoring the activities of the intracellular antioxidant defense system. Therefore, we suggest that possesses neuroprotective effects against 6-OHDA-induced neurotoxicity due to the radical scavenging capacity of its antioxidant phytoconstituents and its ability to restore intracellular antioxidant activities.