Alzheimer's disease (AD) is a neurodegenerative disease and the most common cause of dementia in the U.S. It is the 6th most common cause of death in the U.S. and may be the 3rd most prevalent among older populations. As of 2019, an estimated 5.8 million people in the U.S. have AD. Sufferers of this disease generally exhibit impaired memory, judgement, language, and mood, as well as personality changes. At late stages of the disease, patients become bed-bound and require costly care. Bodily functions such as swallowing may also be impaired.

No disease modifying treatments, which are neuroprotective or neurorestorative rather than just symptomatic, have ever been approved for AD. Clinical trials in this area tend to have a high rate of failure. Few studies are testing natural substances as their agent. Though the cause for AD is unknown, B-amyloid peptide aggregations in neurons is a leading hypothesis.

Glucoraphanin is a glucosinolate, or a water-soluble anion commonly found in plants of the Brassica family as a defense against pests or diseases. Glucosinolates are the chemical precursors to isothiocyanates, and both have antioxidant properties. The conversions are catalyzed by enzymes found in the plant. Glucoraphanin's derivative is sulforaphane, which has shown promising results against B-amyloids in a few studies. The purpose of my research was to determine if the liquid content of broccoli (Brassica oleracea var. italica), as well as isolated glucoraphanin, can reduce the paralysis rate in transgenic C. elegans (strain CL4176). This strain expresses B-amyloid. Worms become paralyzed when they express the peptide and express more at higher temperatures.

To test my hypothesis, I age-synched my worms by moving 50 eggs onto new culture plates. Once they hatched, I placed 2 plates for 2 concentrations of glucoraphanin solution and 2 plates for 2 concentrations of blended and centrifuged broccoli liquid. The low concentrations were determined by scaling a human serving of broccoli to the mass of a worm, and the high concentration was 10 times that. I also had 2 controls of distilled water for a total of 10 plates per trial. I would then upshift the temperature from 16 to 28°C. I counted and recorded the percentage of worms paralyzed per plate 24 hours after upshifting. This procedure was successfully run 4 times.

I found the that control paralysis rate at 24 hours was about 90.9%, the low glucoraphanin concentration was about 83.0%, and the high glucoraphanin concentration was about 73.7%. The low broccoli concentration yielded around a 84.3% paralysis rate, and the high broccoli concentration yielded about 76.8%. Each group was significantly different from the control, and the difference between the two broccoli or the two glucoraphanin concentrations were significant. The difference between the low glucoraphanin concentration and the low broccoli concentration was insignificant, as was the high glucoraphanin concentration compared to the high broccoli concentration.

As my results supported my hypothesis, further studies with different model organisms, more trials, or different glucosinolates and isothiocyanates may be valuable.