Daily chronomics of proteomic profile in aging and rotenone-induced Parkinson’s disease model in male Wistar rat and its modulation by melatonin

Day time-restricted feeding shows differential synchronizing effects on age-related changes of serotonin metabolism in SCN and the pineal gland in male Wistar rats

The circadian timing system is synchronized by the environmental photic and non-photic signals. Light is the major cue that entrains the master circadian oscillator located in suprachiasmatic nucleus (SCN). With aging condition ocular light impairs because of the age-related deficiencies in the eye as a result the clock becomes less sensitive to light. In such case non-photic cues may play a major role in synchronizing the clock. Earlier studies have linked altered meal timings to induce many physiological changes including serotonin in different brain regions such as hypothalamus, brain stem and striatum. Much is not known about the effect of timed food restriction as a non-photic stimulus on serotonergic system in SCN under aging condition. We report here the synchronizing effects of time-restricted feeding (TRF) as a non-photic stimulus on serotonin and its related metabolites in the SCN and pineal gland of male Wistar rats upon aging. Under food restriction daily rhythmicity of serotonin 5-HT and 5-HTOH was abolished whereas NAS, 5-MIAA and NAT showed a significant decrease in their daily pulses upon food restriction in 3 months (m) old rats. Under forced day time feeding schedule the mean 24 h levels of serotonin have significantly decreased in 12 and 24 m old animals in SCN and pineal gland. Most of the serotonin metabolites in the SCN and pineal gland of 12 and 24 m old ad libitum fed group rats have shown rhythmicity. 5-HT, NAS, MEL and NAT have shown daily rhythm in the SCN of 12 and 24 m old rats whereas 5-MIAA and 5-MTOH did not show daily rhythm in both the age groups. The mean 24 h levels of 5-HTP, 5-HIAA, 5-MIAA, 5-MTOH, MEL and NAT were increased in the pineal gland of 12 and 24 months old rats. This work help demonstrate the role of TRF in synchronising age induced desynchronization in serotonin metabolome.

A literature review of the studies concerning selected plant-derived adaptogens and their general function in body with a focus on animal studies

BACKGROUND

Adaptogens are generally referred to the substances, mostly found in plants, which non-specifically increase resilience and chances of survival by activation of signaling pathways in affected cells.

PURPOSE

This literature review was conducted to summarize the investigation, until March 2021, on selected adaptogenic plants and plant-derived substances.

STUDY DESIGN

Electronic databases were searched (up to March 2021) for in vitro and animal studies, as well as clinical trials. Moreover, all modes of action connected with the adaptogenic effects of plants and phytochemicals were collected.

METHODS

The search of relevant studies was performed within electronic databases including Scopus, Science Direct, PubMed, and Cochrane library. The most important keywords were adaptogen, plant, phytochemical, and plant-derived.

RESULTS

The most investigated medicinal herbs for their adaptogenic activity are Eleutherococcus senticosus, Panax ginseng, Withania somnifera, Schisandra chinensis, and Rhodiola spp., salidroside, ginsenosides, andrographolide, methyl jasmonate, cucurbitacin R, dichotosin, and dichotosininare are phytochemicals that have shown a considerable adaptogenic activity. Phytochemicals that have been demonstrated adaptogenic properties mainly belong to flavonoids, terpenoids, and phenylpropanoid glycosides.

CONCLUSION

It is concluded that the main modes of action of the selected adaptogenic plants are stress modulatory, antioxidant, anti-fatigue, and physical endurance enhancement. Other properties were nootropic, immunomodulatory, cardiovascular, and radioprotective activities.

Therapeutic effects of hydro-alcoholic leaf extract of Withania somnifera on age-induced changes in daily rhythms of Sirt1, Nrf2 and Rev-erbα in the SCN of male Wistar rats

The temporal expression pattern of the circadian clock genes are known to be altered/attenuated with advance in age. Withania somnifera (WS) essentially consists of numerous active constituents including withanolides is known to have antioxidant, anti-inflammatory and adaptogenic properties. We have earlier demonstrated therapeutic effects of hydro-alcoholic leaf extract of WS on the age-induced alterations in the levels and daily rhythms of various clock genes such as rBmal1, rPer1, rPer2 and rCry1. We have now studied effects of hydro-alcoholic leaf extract of WS on the age-induced alterations in the levels and daily rhythms of expression of SIRT1 (an NAD⁺ dependent histone deacetylase and a modulator of clock) and NRF2 (a clock controlled gene and a master transcription factor regulating various endogenous antioxidant enzymes) in addition to rRev-erbα in SCN of adult [3 months (m)], middle-aged (12 m) and old-aged (24 m) male Wistar rats. The daily rhythms of rNrf2 expression showed 6 h phase delay in middle age and 12 h phase advance in old age. WS restored rSirt1 daily rhythms and phase in old age whereas it restored the phase of rNrf2 in the SCN of both middle and old aged animals. At protein level, SIRT1 expression showed phase advances in 12 m and 24 m whereas NRF2 daily rhythms were abolished in both the age groups. WS restored the phase and daily rhythms of SIRT1 as well as NRF2 in 12 m old rats. However, rRev-erbα expression was found insensitive to WS treatment in all the age groups studied. Pairwise correlation analysis demonstrated significant stoichiometric interactions among rSirt1, rNrf2 and rRev-erbα in 3 m which altered with aging significantly. WS treatment resulted in differential restorations of such interactions.