Utility of fatty acid profile and in vitro immune cell activation for chemical and biological standardization of Arthrospira/Limnospira

Authors: HUH, JUNGMOO - University Of Mississippi; ZHANG, JIN - University Of Mississippi; HAUEROVÁ, RADKA - University Of South Bohemia; LEE, JOSEPH - University Of Mississippi; HAIDER, SAQLAIN - University Of Mississippi; Wang, Mei; HAUER, TOMÁS - University Of South Bohemia; KHAN, IKHLAS - University Of Mississippi; CHITTIBOYINA, AMAR - University Of Mississippi; PUGH, NIRMAL - University Of Mississippi

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/31/2022
Publication Date: 9/19/2022
Citation: Huh, J., Zhang, J., Hauerová, R., Lee, J., Haider, S., Wang, M., Hauer, T., Khan, I., Chittiboyina, A., Pugh, N. 2022. Utility of fatty acid profile and in vitro immune cell activation for chemical and biological standardization of Arthrospira/Limnospira. Scientific Reports. https://doi.org/10.1038/s41598-022-19590-x.
DOI: https://doi.org/10.1038/s41598-022-19590-x

Interpretive Summary: Commercially cultivated Limnospira (species formerly classified to genus Arthrospira, common name spirulina) is a popular food/supplement consumed by millions of people worldwide for health benefits, including its potential utility to enhance host immune resilience against viral infections. Despite the popularity of this botanical dietary supplement, little work has been achieved on standardization methods. In the current research, a chemico-biological approach was identified for standardizing the immune-enhancing activity of Limnospira by using a combination of an in vitro bioassay (detection of Toll-like receptor [TLR]2/TLR1 activity) and an analytical method (detection of fatty acid content). Measurement of TLR2/TLR1-dependent activity detects Braun-type lipoprotein activity, the predominant compounds responsible for the in vitro macrophage activation potential of Limnospira. Fatty acid content was highly correlated with activity and therefore expands the utility of this chemical marker to standardization efforts. These standardization methods can be used to ensure consistent product quality for consumers and properly characterize biomass for future scientific research endeavors.

Technical Abstract: Commercially cultivated Limnospira (species formerly classified to genus Arthrospira) is a popular food/supplement consumed by millions of people worldwide for health benefits, including its potential utility to enhance host immune resilience against viral infections. We have previously identified lipoproteins of the Braun-type as the major in vitro macrophage-activating principal within this cyanobacterium. The objective of the current research was to advance the standardization technology for assessing variation in product quality from different batches and sources of biomass. Quantitative methods were established using botanically verified biomass to detect fatty acids as potential chemical markers and lipoprotein immune-enhancing activity (an in vitro bioassay for activation of TLR2/TLR1 signaling pathway). Subsequent analysis of 20 different batches of biomass obtained from one commercial grower (collected over 14 years) demonstrated that the sum of two fatty acids (linoleic, and y linolenic) was positively correlated with TLR2/TLR1-dependent activation (R2 = 0.48, p = 0.0007). Further investigation of 12 biomass samples sourced from commercial growers in 10 different countries demonstrated that fatty content was again a predictor of biological activity (R2 = 0.72, p = 0.0005). Between the different biomass sources, the content of fatty acids varied by 2-fold and activity by 12.5-fold. This large variation between different biomass product materials confirms the need to use the present chemical and bioassay-based standardization methods to ensure consistent product quality for consumers and properly characterize biomass for future scientific research endeavors.