Antinociceptive, anti-inflammatory and hypoglycemic activities of the ethanolic Turnera subulata Sm. flower extract in adult zebrafish (Danio rerio)

Abstract

Turnera subulata Sm. belongs to the family Turneraceae and is found in Brazil. The present study evaluated the antinociceptive, anti-inflammatory, and hypoglycemic potential of T. subulata flower extract (EtFloTsu) in zebrafish (Danio rerio). The total phenol and flavonoid contents of EtFloTsu were determined and identified using the Folin Ciocalteu reagent and aluminum chloride (AlCl₃), respectively. The constituents of the extract were identified by HPLC-DAD, and the in vitro antioxidant activity (DPPH) was determined, toxicity in brine shrimp, and acute toxicity of 96 h in adult zebrafish. In addition, adult zebrafish (n = 6/fish) were treated orally with EtFloTsu (4, 20, or 40 mg/kg; vo) and subjected to formalin-induced nociception tests (with its possible mechanism of action with camphor), carrageenan-induced inflammation, and D-glucose-induced hyperglycemia (111 mM). Oxidative stress in the liver and brain tissues was assessed. EtFloTsu showed high levels of phenolic and flavonoid compounds with antioxidant activity. The phytochemicals chlorogenic acid, luteolin-7-o-glucoside, vitexin, and apigenin-7-o-glucoside were also identified in EtFloTsu. The synergism between these constituents was possibly responsible for the antinociceptive (via TRPA1), anti-inflammatory, and hypoglycemic effects of EtFloTsu in adult zebrafish, without causing toxicity in animals. Therefore, T. subulata flowers have therapeutic agents that could treat pain, inflammation, diabetes, and related complications.

Communicated by Ramaswamy H. Sarma

Keywords:

• Adult zebrafish
• diabetes
• inflammation
• nociception
• Turnera subulata

Acknowledgment

Program in Biotechnology (RENORBIO) at the State University of Ceará We thank our collaborators at the Laboratory of Biotechnology and Molecular Biology (LBBM) of the State University of Ceará (UECE), the Laboratory of Natural Products – Bioprospecting and Biotechnology of the State University of Ceará (UECE – CECITEC Campus Tauá), the Laboratory of Product Chemistry (LQPN-Bloco S), the Group of Theoretical Chemistry and Electrochemical (GQTE), and the Department of Organic and Inorganic Chemistry at the Federal University of Ceará (UFC). Hélcio S. dos Santos acknowledges financial support from the PQ/FUNCAP (Grant#: BP4-0172-00075.01.00/20).

Consent for publication

Not applicable.

Disclosure statement

All authors declare that they have no conflicting interests.