Anoectochilus roxburghii flavonoids extract ameliorated the memory decline and reduced neuron apoptosis via modulating SIRT1 signaling pathway in senescent mice

J Ethnopharmacol. 2022 Oct 5:296:115361. doi: 10.1016/j.jep.2022.115361. Epub 2022 May 21.

Abstract

Ethnopharmacological relevance: Anoectochilus roxburghii (A. roxburghii) is a precious herb and folk medicine in many Asian countries. It has been used traditionally to treat diabetes, etc., and also used as a dietary therapy to delay senescence.

Aim of the study: This study was to evaluate the neuroprotective effects of A. roxburghii flavonoids extract (ARF) and whether its effects were due to the regulation of SIRT1 signaling pathway in senescent mice and in D-galactose (D-gal) induced aging in SH-SY5Y cells.

Materials and methods: 18-month-old mice were randomly divided into senescent model, low-dose ARF, high-dose ARF and vitamin E group. 2-Month-old mice were as a control group. After 8 weeks treatment, Morris water maze (MWM) was performed. The levels of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), monoamine oxidase (MAO) and acetylcholinesterase (ACh-E) in the cortex were determined. Hippocampus morphologic changes were observed with haematoxylin and eosin (H&E), Nissl, senescence-associated-galactosidase (SA-β-gal) and terminal deoxynucleotidyl transferase nick-end labeling (TUNEL) staining. Apoptosis-related molecular expressions in the hippocampus were performed by western blotting. Furthermore, after stimulated by EX527 (a SIRT1 inhibitor), the SIRT1-dependent neuroprotective effects of ARF were determined by measuring SRIT1 and p53 expression in SH-SY5Y aging cells induced by D-gal.

Results: ARF could significantly ameliorate memory decline in senescent mice and reduce the generations of ROS, MDA and the activities of MAO and ACh-E, while increasing SOD activities in the cortex of aging mice. ARF obviously improved hippocampus pathological alterations, increased the number of Nissl bodies, while reducing senescent and apoptotic cells in senescent mice hippocampus. Further, ARF positively regulated SIRT1 expression, and reduced apoptosis-related molecules p53, p21 and Caspase-3 expression, while increasing the ratio of Bcl-2/Bax. In D-gal-induced SH-SY5Y cells, the effects of ARF on SIRT1 and p53, and the ability of scavenging ROS were mostly abolished after incubation with the EX527.

Conclusions: ARF, in a SIRT1-dependent manner, exerted neuroprotection via modulating SIRT1/p53 signaling pathway against memory decline and apoptosis due to age-induced oxidative stress damage in senescent mice.

Keywords: A. roxburghii flavonoids Extract (ARF); Memory decline; Neuron apoptosis; SIRT1; Senescence.

MeSH terms

  • Acetylcholinesterase / metabolism
  • Animals
  • Apoptosis
  • Flavonoids / pharmacology
  • Flavonoids / therapeutic use
  • Galactose
  • Humans
  • Memory Disorders / chemically induced
  • Memory Disorders / drug therapy
  • Memory Disorders / pathology
  • Mice
  • Monoamine Oxidase / metabolism
  • Neuroblastoma* / pathology
  • Neurons
  • Neuroprotective Agents* / pharmacology
  • Neuroprotective Agents* / therapeutic use
  • Orchidaceae*
  • Oxidative Stress
  • Reactive Oxygen Species / metabolism
  • Signal Transduction
  • Sirtuin 1 / metabolism
  • Superoxide Dismutase / metabolism
  • Tumor Suppressor Protein p53 / metabolism

Substances

  • Flavonoids
  • Neuroprotective Agents
  • Reactive Oxygen Species
  • Tumor Suppressor Protein p53
  • Superoxide Dismutase
  • Monoamine Oxidase
  • Acetylcholinesterase
  • SIRT1 protein, human
  • Sirt1 protein, mouse
  • Sirtuin 1
  • Galactose