Zebrafish models for studying central nervous system effects of Ayurvedic medicinal plants

Abstract

Traditional Indian medicine (Ayurveda) has a long history of treating central nervous system (CNS) disorders. Ayurvedic plants are typically rich in flavonoids, lignans, sterols, tannins and alkaloids that exert potent anti-inflammatory, anti-oxidant, neuroprotective and neurotropic effects in both humans and rodents. The zebrafish (Danio rerio) has emerged as a useful model species and a powerful vertebrate in vivo system for CNS disease modeling and drug screening. As zebrafish continue to demonstrate their growing utility for studying a wide range of pharmaceutical therapies, including Chinese and American traditional medicines, here we discuss CNS effects of various Ayurvedic medicinal plants, and how they can be further elucidated using zebrafish models. We also evaluate the existing challenges and limitations of using zebrafish models for studying Ayurvedic pharmacotherapy, as well as outline future directions of translational research in this field.

Keywords: Ayurveda; Brain disorders; Novel drugs; Treatment; Zebrafish.

Fig. 1

Selected examples of CNS effects of Ayurvedic medicinal plants in zebrafish models.Ceratonia siliqua L. (carob) is a Mediterranean medicinal plant prevents the cognitive impairment of 6-hydroxydopamine (6-OHDA, a Parkinson's disease (PD) model) [62]. Ashwagandha (Withania somnifera Dunal) leaf extract ameliorated the increase in the pyknotic neuronal counts in periventricular gray zone caused by benzo[a]pyrene neurotoxicity [60]. The extract of tulsi leaves reduces memory deficits caused by scopolamine in zebrafish [63]. Curcumin, the main ingredient of turmeric, protects against the locomotor impaired caused by rotenone (a PD-like model) [61].

Fig. 2

Summary of common behavioral and physiological CNS effects involved in preclinical activity of Ayurvedic medicines. Data represent the occurrence of specific effects in plans discussed here and listed in Table 1-Supplementary material. GABA - gamma aminobutyric acid.