Effect of Centella asiatica ethanol extract on zebrafish larvae (Danio rerio) insomnia model through inhibition of Orexin, ERK, Akt and p38

Background: Insomnia is difficulty initiating or maintaining sleep for at least three nights a week or more and lasting for at least 3 months. One of the molecules that play a role in the circadian rhythm of arousal system is hypocretin/orexin. Orexin activates the p38-MAPK signaling pathway and increases phosphorylated ERK1/2 levels. Centella asiatica (CA) has a role in the signal work of the MAPK/ERK, Akt, and p38 path in many various diseases. Methods: : The research method used is true laboratory experimental. The research approach used was randomized control group post-test only. Zebrafish embryos aged 0-7 dpf were used in this study. The treatment group consisted of 5 groups: normal, insomnia, insomnia + 2.5 μg/mL CA, insomnia + 5 μg/mL CA, and insomnia + 10 μg/mL CA. The locomotor motion of zebrafish larvae was observed using Basler cameras on days five-, six- and seven-day post fertilization (dpf), then analyzed by using Western Blot method. Results: : The results proved that exposure to CA extract was able to reduce the expression of orexin (91963 ± 9129) and p38 (117425 ± 6398) as an arousal trigger in the sleep-wake cycle, with the most optimal concentration of CA 5 μg/mL. Exposure to CA extract was also able to reduce the expression of ERK (94795 ± 30830) and Akt (60113.5 ± 27833.5) with an optimum concentration of CA 2.5 μg/mL. Conclusion: Exposure to CA extract was able to improve the sleep activity of zebrafish larvae insomnia model by extending the total inactivity time ( cumulative duration ) and shortening the duration of first sleep ( latency to first ) in light and dark phases through inhibition of orexin, ERK, p38, and Akt.