Comparative and Functional Screening of Three Species Traditionally used as Antidepressants: Valeriana officinalis L., Valeriana jatamansi Jones ex Roxb. and Nardostachys jatamansi (D.Don) DC.

Abstract

The essential oils (EOs) of three Caprifoliaceae species, the Eurasiatic Valeriana officinalis (Vo), the Himalayan Valeriana jatamansi (Vj) and Nardostachys jatamansi (Nj), are traditionally used to treat neurological disorders. Roots/rhizomes micromorphology, DNA barcoding and EOs phytochemical characterization were carried out, while biological effects on the nervous system were assessed by acetylcholinesterase (AChE) inhibitory activity and microelectrode arrays (MEA). Nj showed the highest inhibitory activity on AChE (IC50 67.15 μg/mL) followed by Vo (IC50 127.30 μg/mL) and Vj (IC50 246.84 μg/mL). MEA analyses on rat cortical neurons, carried out by recording mean firing rate (MFR) and mean bursting rate (MBR), revealed stronger inhibition by Nj (IC50 18.8 and 11.1 μg/mL) and Vo (16.5 and 22.5 μg/mL), compared with Vj (68.5 and 89.3 μg/mL). These results could be related to different EO compositions, since sesquiterpenes and monoterpenes significantly contribute to the observed effects, but the presence of oxygenated compounds such as aldehydes and ketones is a discriminating factor in determining the order of potency. Our multidisciplinary approach represents an important tool to avoid the adulteration of herbal drugs and permits the evaluation of the effectiveness of EOs that could be used for a wide range of therapeutic applications.

Back to the Roots—An Overview of the Chemical Composition and Bioactivity of Selected Root-Essential Oils

“…The white to pink inflorescences develop in the second year after vernalization. The rootstock forms a dense meshwork of thin roots [ 302 ], [ 13 ] (p.692), with a clonical, dull brown colored rhizome and many long strout attached roots [ 304 ]. While the fresh root is odorless, dried roots smell distinctly unpleasant, comparable with valeric acid and camphor [ 305 , 306 ].…”

“…Furthermore, >0.17% valerenic acids are requested [ 307 ]. Oxygenated monoterpenes, monoterpene hydrocarbons, oxygenated sesquiterpenes, and sesquiterpene hydrocarbons were registered as the most abundant constituents [ 304 , 315 ]. Several publications on valerian root oils clearly indicated remarkable compositional differences, according to various geographic origins.…”

“…Also, the steam distilled EO from commercial V. officinalis roots/rhizome grown in China, with 39 identified constituents, was mainly characterized by bornyl acetate (46.9%) as the principal ingredient, although the other most representative compounds differed, apart from camphene (13.9%). They included trans -valerenyl acetate (13.2%), mirtenyl acetate (3.9%), α-pinene (3.4%), and β-pinene (2.8%) [ 304 ]. Similarly, another Chinese (Hubei Province) V. officinalis root EO, obtained by hydrodistillation, was also dominated by bornyl acetate (48.2%), camphene (13.8%), β-pinene (2.8%), α-pinene (2.7%), borneol (2.1%), and myrtenyl acetate (2.0%).…”

“…Results indicate concentration-dependent AChEinhibitory activity (IC 50 = 127.30 µg/mL), and decrease in the spontaneous electrical activity of in vitro corticonal neuronal networks until the complete loss of activity. Compared to the EOs of Nardostachys jatamansi and V. jatamansi , which are often fraudulently used as adulterants, V. officinalis EO exerted the second strongest inhibition, while the EO of N. jatamansi induced throughout the highest inhibitory activity [ 304 ]. Previous studies evaluated the inhalative effect of V. officinalis EO on autonomic nerve activity in depressed as well as healthy subjects.…”

Plant Species of Sub-Family Valerianaceae—A Review on Its Effect on the Central Nervous System

“…These protective effects are due to the ability of V. officinalis and its main constituents such as valerenic acid and acetylvalerenolic acid, to inhibit the activity of the nuclear factor (NF)-κB in vitro [ 165 ]. Other studies showed that the CNS effects of V. officinalis, V. jatamansi, and N. jatamansi can certainly also attributed to the inhibitory activity exerted on AChE [ 166 ].…”