For a more detailed review of the current understanding of how oxidative stress and inflammation are involved in the aging process see this chapter from a longer book: Oxidative Stress and the Aging Brain: From Theory to Prevention, 
Mitochondria are the main energy producers in cells. They are involved in breaking down each molecule of glucose (one half of the larger molecule that is commonly known as sugar). During the process of breaking the chemical bonds found in the glucose molecule the free radicals that can cause oxidative damage are produced. When adequate antioxidants are available the free radicals are stabilized before they can cause damage. The body’s internally produced antioxidant enzymes also require the trace minerals copper, zinc and manganese. /Separate topic: An imbalance in copper and zinc can cause health problems./
“Free radicals are chemical species with a single unpaired electron. The unpaired electron is highly reactive as it seeks to pair with another free electron; this results in the production of another free radical. The newly produced free radical is unstable in most cases and, as a result, it can also react with another molecule to produce yet another free radical. Thus, a chain reaction of free radicals can occur, leading to more and more damaging reactions.” 
“Several antioxidant defense mechanisms have evolved to protect cell components from the attack of oxidative stress and associated oxidative damage. These mechanisms include antioxidant enzymes, such as SOD, superoxide reductases, catalase, glutathione peroxidases (Gpx), and many heat-shock proteins.” “SOD exists in two forms: Cu/ZnSOD is present primarily in the cytoplasm while MnSOD is present primarily in the mitochondria.” 
More information about manganese superoxide dismutase (MnSOD) and how mitochondria function is available here: MnSOD in Oxidative Stress Response-Potential Regulation viaMitochondrial Protein Influx 
Supplementing the diet with a manganese and other trace minerals may be helpful as manganese and other trace minerals may be chelated by glyphosate, the active ingredient of the herbicide RoundUp. Chelation is a chemical term for the tendency for one chemical to bind with another – take hold and make the other one less freely available in the environment. The process can be helpful in some situations as it can act as a carrier, a taxi cab so to speak, but at other times it is simply removing the other chemical from being available for other uses.
Plant scientists are aware of the problem and there are agricultural suggestions for reducing the negative effects of manganese chelation by glyphosate in the following article: What About Glyphosate-Induced Manganese Deficiency? The effects of glyphosate’s chelation of iron, copper and zinc is also included in addition to the discussion of manganese.  The summary of plant yield research found that improved crop yields were produced when manganese, copper and zinc were applied as a supplemental fertilizer a certain amount of time after the glyphosate containing herbicide was applied to the fields:
“The greatest soybean yield response on high organic soils
was with both Mn and Cu applied 8 to 12 days after the glyphosate.
The highest yields for corn were obtained by foliar-applying Zn 15
days after glyphosate was applied in northwestern Indiana,” 
So if plant health scientists recommend supplementing with manganese, copper and zinc for best plant health do human health scientists? Some do, but the topic is still considered alternative medicine rather than being a mainstream medical recommendation.  Risks of increased toxicity from trace metals that have negative health effects such as aluminum. 
Antioxidant rich foods or supplements that were discussed in the chapter on Oxidative Stress and Aging include vitamin E, which had positive results when used as a supplement in animal studies and mixed results in studies with humans, addition of whole foods such as nuts which are a good source of vitamin E and other nutrients had more consistent positive results in human clinical research studies; Green Tea and its active metabolite EGCG; blueberries, spinach and spirulina, a blue-green algae. 
- Disclaimer: Opinions are my own and the information is provided for educational purposes within the guidelines of fair use. While I am a Registered Dietitian this information is not intended to provide individual health guidance. Please see a health professional for individual health care purposes.
- Carmelina Gemma, Jennifer Vila, Adam Bachstetter, and Paula C. Bickford, Chapter 15: Oxidative Stress and the Aging Brain: From Theory to Prevention, from Brain Aging: Models, Methods, and Mechanisms. Riddle DR, editor. Boca Raton (FL): CRC Press/Taylor & Francis; 2007. https://www.ncbi.nlm.nih.gov/books/NBK3869/
- Demet Candas and Jian Jian Li, MnSOD in Oxidative Stress Response-Potential Regulation viaMitochondrial Protein Influx, Antioxid Redox Signal. 2014 Apr 1; 20(10): 1599–1617. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3942709/
- Don M. Huber, What About Glyphosate-Induced Manganese Deficiency?, Fluid Journal, Fall 2007, http://www.agweb.com/assets/import/files/58p20-22.pdf
- Anthony Samsel and Stephanie Seneff, Glyphosate, pathways to modern diseases III: Manganese, neurological diseases, and associated pathologies, Surg Neurol Int. 2015; 6: 45. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4392553/