Depression and Its Phytopharmacotherapy-A Narrative Review

Abstract

Depression is a mental health disorder that develops as a result of complex psycho-neuro-immuno-endocrinological disturbances. This disease presents with mood disturbances, persistent sadness, loss of interest and impaired cognition, which causes distress to the patient and significantly affects the ability to function and have a satisfying family, social and professional life. Depression requires comprehensive management, including pharmacological treatment. Because pharmacotherapy of depression is a long-term process associated with the risk of numerous adverse drug effects, much attention is paid to alternative therapy methods, including phytopharmacotherapy, especially in treating mild or moderate depression. Preclinical studies and previous clinical studies confirm the antidepressant activity of active compounds in plants, such as St. John's wort, saffron crocus, lemon balm and lavender, or less known in European ethnopharmacology, roseroot, ginkgo, Korean ginseng, borage, brahmi, mimosa tree and magnolia bark. The active compounds in these plants exert antidepressive effects in similar mechanisms to those found in synthetic antidepressants. The description of phytopharmacodynamics includes inhibiting monoamine reuptake and monoamine oxidase activity and complex, agonistic or antagonistic effects on multiple central nervous system (CNS) receptors. Moreover, it is noteworthy that the anti-inflammatory effect is also important to the antidepressant activity of the plants mentioned above in light of the hypothesis that immunological disorders of the CNS are a significant pathogenetic factor of depression. This narrative review results from a traditional, non-systematic literature review. It briefly discusses the pathophysiology, symptomatology and treatment of depression, with a particular focus on the role of phytopharmacology in its treatment. It provides the mechanisms of action revealed in experimental studies of active ingredients isolated from herbal antidepressants and presents the results of selected clinical studies confirming their antidepressant effectiveness.

Keywords: antidepressant; depression; herbal; medicinal plants; treatment.

Figure 1

The main pathomechanisms of depression. The main structures associated with the pathogenesis of depression are the prefrontal cortex and the limbic system (including the hippocampus and the amygdala). According to the comprehensive, psycho-neuro-immuno-endocrinological theory of the development of depression, this disease results from the action of multiple exogenous and endogenous factors. Details are given in the text. (HPA—hypothalamic-pituitary-adrenal axis; 5HT—5-hydroxytryptamine; serotonin; NA—noradrenaline; DA—dopamine).

Figure 2

The summary of the elements of the mechanisms of action of plants with antidepressant activity. According to the theory of synergistic and polyvalent action of active ingredients contained in medicinal plants (symbolically marked in the figure with selected chemical formulas), the antidepressant effect is the result of the action of numerous co-occurring active compounds. The pharmacodynamics of these compounds involve similar mechanisms to those attributed to synthetic antidepressants. However, unlike synthetic antidepressants, an important aspect of the antidepressant effect of herbal preparations is also their anti-inflammatory action. Details are given in the text. (HPA—hypothalamic-pituitary-adrenal axis; 5HT—5-hydroxytryptamine; serotonin; NA—noradrenaline; GABA—gamma-aminobutyric acid; α—adrenergic; M—muscarinic; D—dopaminergic; CB—cannabinoid).