Background
Alzheimer's disease (AD) is a progressive neurodegenerative disorder with poorly understood pathology. Elevated tau, phospho-tau and mitochondrial dysfunction are significantly correlated with an increased risk of AD and are therefore targets for disease-modifying therapy. In this study, we examined the effects of polyphenolic extracts from six different varieties of sorghum: Shawaya short black-1 (Black), IS1311C (Brown), QL33/QL36 (Red), B923296 (Red), QL12 (White), and QL33 (Red) on the attenuation of beta amyloid-induced phospho-tau levels, total tau levels, and mitochondrial dysfunction in neuronal cells. Method: Tau proteins (231 (pT231), Serine- 199 (pS199), and total tau proteins (T-tau)) were detected and quantified using sandwich ELISA kits, while mitochondrial dysfunction was measured in terms of mitochondrial membrane potential (Δψm) and adenosine triphosphate (ATP) levels.
Conclusions
The polyphenol extracts from sorghum attenuated the tau toxicity and Aβ-induced mitochondrial dysfunction in a variety- and dose-dependent manner and made a promising disease-modifying agent against AD. However, extensive research is needed to validate the efficacy of the sorghum extracts prior to animal and clinical studies.
Results
Almost all varieties of the sorghum extracts reduced the beta amyloid-induced pS199 and pT231 levels (p ≤ 0.05). The optimum concentration of QL33/QL36 (1000 µg/mL), QL12 (2000 µg/mL), and QL33 (2000 µg/mL) strongly attenuated the phospho-tau level. Sorghum IS1311C (750 µg/mL) showed the highest Δψm reduction (39.8%), whereas QL33 (2000 µg/mL) most strongly improved the ATP level (37.7%) (p ≤ 0.01). For both Δψm and ATP assays, the least activity was observed in sorghum B923296 at 21% and 25.5%, respectively (p ≤ 0.01). Conclusions: The polyphenol extracts from sorghum attenuated the tau toxicity and Aβ-induced mitochondrial dysfunction in a variety- and dose-dependent manner and made a promising disease-modifying agent against AD. However, extensive research is needed to validate the efficacy of the sorghum extracts prior to animal and clinical studies.