Pharmacological evaluation of the anxiolytic-like effects of Lippia graveolens and bioactive compounds

Abstract

Context:Lippia species (Verbenaceae) are widely used in Latin America and Africa as folk medicine for their tranquilizing properties.Objective: To evaluate the anxiolytic-like effects and safety of Lippia graveolens Kunth. by exploring its aqueous and organic leaf extracts and identifying the responsible chemical constituents.Material and methods: Aqueous and organic extracts (hexane, ethyl acetate and methanol) were pharmacologically evaluated at several doses. Chemical constituents were identified using MS, NMR and GC-MS analysis. The isolated compounds (3 mg/kg, i.p.), extracts (1, 3, 10 and 30 mg/kg, i.p.), and the reference drug diazepam (0.1 mg/kg, i.p.) were assessed in CD-1 mice using experimental behavioural models: open-field, cylinder, hole-board, plus-maze and sodium pentobarbital-induced hypnosis, as well as their acute toxicity (LD50).Results: After administration of the extracts and bioactive compounds, a significant anxiolytic-like response from 1 mg/kg, i.p. was observed, resembling the effect of diazepam. Major presence of thymol (33.40%) was observed in the hexane extract; whereas for the first time in this species a p-cymene + thymol mixture (9.78%), naringenin (0.18%) and cirsimaritin (1.16%) were obtained as bioactive constituents of the ethyl acetate crude extract. Acute toxicity was calculated to be LD50 = 1000 mg/kg for the crude hexane extract, lower in comparison to the other extracts analyzed (LD50 > 2000 mg/kg).Discussion and conclusion: Our results suggest that L. graveolens exerts anxiolytic-like activity involving many kinds of constituents, mainly of the terpenoid and flavonoid nature. These results reinforce the potential use of this species in the therapy of anxiety.

Neuropharmacology of Secondary Metabolites from Plants with Anxiolytic and Antidepressant Properties

“…Anxiolytic properties have also been attributed to terpenes. A combination of two monoterpenoids, p-cymene + thymol, both at doses of 3mg/kg i.p., produced anxiolytic effects on the hole-board test (HBT) and EPM [24]. Studies have also demonstrated that (À)-myrtenol, a monoterpenoid alcohol, produced an anxiolytic effect on EPM at doses of 25, 50, and 75 mg/kg, i.p., though only the 25-and 50-mg/kg doses did so on LDB.…”

Efecto del estrés salino sobre la morfología y fitoquímica de orégano mexicano (Lippia graveolens Kunth) cultivado in vitro

“…Algunos de los fenoles reportados en L. graveolens son timol, carvacrol, quercetina, O-hexosido, escutelarina etc. (González-Trujano et al, 2017). La identidad de los fenoles y flavonoides que se extrajeron en este estudio y su relación directa con la capacidad antioxidante no fueron determinados en este estudio, sin embargo, actualmente se está trabajando en esta parte.…”

“…Una de las plantas mexicanas pertenecientes a esta familia es Lippia graveolens Kunth (Orégano mexicano). Esta planta tiene usos culinarios, en la farmacéutica, así como para tratamiento de diversos padecimientos (Pascual et al, 2001;González-Trujano et al, 2017), entre otros. Por la zona donde crece el orégano naturalmente, éste tiene que soportar periodos de poca precipitación lo cual puede resultar en situaciones de estrés (Mata-González y Meléndez- González, 2005;Martínez-Hernández et al, 2015).…”

Evaluation of Somaclonal and Ethyl Methane Sulfonate-Induced Genetic Variation of Mexican Oregano (Lippia graveolens H.B.K.)

“…It is an aromatic species whose essential oil is composed primarily of two monoterpenes, thymol and carvacrol, to which various properties and uses have been attributed [5]. The essential oil is used in the soft drink, liquor, cosmetics, and pharmaceutical industry [1,6], in the manufacturing of soaps, perfumes, and aromatherapy products, and as an antimicrobial [7,8] and antioxidant [9,10] product.…”