Modulation of Neurogenesis through the Promotion of Energy Production Activity Is behind the Antidepressant-Like Effect of Colonial Green Alga, Botryococcus braunii

Abstract

Algae have been recognized as important resources providing functional components due to their capacity to exert beneficial effects on health. Therefore, there is increasing interest in investigating the biological activity of algae. In this study, we evaluated the antidepressant-like effect of the administration of 100 mg/kg/day of the ethanol extract of colonial green alga Botryococcus braunii (EEB) for 14 consecutive days in the forced swimming test (FST)-induced depression in imprinting control region (ICR) mice. Imipramine, a commercial antidepressant drug, was used as a positive control. In addition, we investigated the molecular mechanisms underlying the effect of EEB by measuring ATP production and by assessing any change in gene expression at the end of the treatment using real-time polymerase chain reaction (PCR) and microarray assays. We showed that the immobility time in the water-administered control (FST stress) group gradually increased from day 1 to day 14. However, treatment with EEB caused a significant decrease of immobility time in the FST compared with that in the FST stress group. Microarray and real-time PCR results revealed that EEB treatment induced variation in the expression of several genes associated with neurogenesis, energy metabolism, and dopamine synthesis. Interestingly, we revealed that only EEB treatment enhanced the promotion of energy production, while treatment with imipramine was ineffective. Our study provides the first evidence that B. braunii enhances energy production, which may contribute to the modulation of neurogenesis and to the enhancement of dopaminergic function, in turn potentially underlying the antistress- and antidepressant-like effects that we observed.

Antidepressant‐Like Effect of Ferulic Acid via Promotion of Energy Metabolism Activity

“…The entire limbic area of the mouse brain containing the cortex, hippocampus, and amygdale was quickly dissected on ice and was minced for RNA extraction. Total RNA was purified from cerebral tissue using the ISOGEN kit (Nippon Gene Co. Ltd., Tokyo, Japan) following the manufacturer's instructions as reported previously . Total RNA was quantified and assessed for quality with NanoDrop 2000 spectrophotometer (Thermo SCIENTIFIC, Wilmington, DE, USA).…”

“…DNA microarray analysis was performed as reported previously . Double‐stranded cDNA was synthesized from 100 ng of total RNA with the GeneAtlas 3′ IVT Express Kit (Affymetrix Inc., Santa Clara, CA, USA).…”

Modulation of the neurotransmitter systems through the anti-inflammatory and antidepressant-like effects of squalene from Aurantiochytrium sp.

“…The dried algal powder was extracted following previous report [10]. Dry powder of Aurantiochytrium sp.…”

“…In recent years, microalgal biomass has also gained increasing interest as an attractive source for the sustainable production of physiologically active substances, such as polyunsaturated fatty acids (PUFAs), carotenoids, phycobiliproteins, polysaccharides, and phycotoxins. We have recently reported the antidepressant-like effects of the colonial green alga Botryococcus braunii by modulating neurogenesis and enhancing dopaminergic function [10].…”

Anti-Inflammatory Effects of Aurantiochytrium limacinum 4W-1b Ethanol Extract on Murine Macrophage RAW264 Cells

“…A water-extracted fraction of Botryococcus braunii showed biological activities of dermatological interest [1]. Additionally, an ethanol extract of B. braunii showed antidepressant-like effects in a mouse behavior test [2]. Several studies have reported the anti-inflammatory effects of microalgal extracts on mammalian cells [3–5].…”