Antidepressant-Like Effects of Sanggenon G, Isolated from the Root Bark of <i>Morus alba</i>, in Rats: Involvement of the Serotonergic System

Abstract

The root bark of Morus alba is commonly used as an alternative medicine due to its numerous health benefits in humans. However, the antidepressant effects of various active components from M. alba have not been fully elucidated. In this study, we aimed to determine whether sanggenon G, an active compound isolated from the root bark of M. alba, exhibited antidepressant-like activity in rats subjected to forced swim test ( Key words Morus alba; sanggenon G; depression; serotonin; forced swim testDepression is a chronic disease that has an enormous impact on society. According to the predictions of the World Health Organization, by the year 2020, depression will be the second leading global burden of illness.1) Despite recent progress in the development of clinically relevant antidepressant drugs, currently available antidepressant are not totally effective and are associated with many undesirable adverse effects.2) Because of the limitations of antidepressant drugs, alternative approaches, such as medicinal herbs, have been studied for their potential applications in the treatment of depression.3,4) Moreover, many herbal extracts have been shown to have antidepressant effects in a variety of animal models. For example, Hypericum perforatum, also known as St. John's wort, is widely used for the treatment of mild to moderate depression. 5) Panax ginseng, commonly known as Korea Ginseng, has been investigated experimentally and clinically for its stress-attenuating activity. 6,7)The mulberry tree (Morus alba L.), one of the most wellknown and widely distributed trees of the family Moraceae, is extensively cultivated in East Asia; the leaves of M. alba L. are an indispensable food source for silkworms, and the fruits are consumed in normal diets.8) The root bark of M. alba is commonly known by the Chinese name of "Sang-Bai-Pi" and is widely used for its anti-inflammatory, antihypertensive, diuretic, and antipyretic effects. 9) M. alba extracts have also been reported to possess hypotensive, 10) hypoglycemic, 11) hepatoprotective, 12) neuroprotective, 13) and anti-inflammatory 14) activities. However, while M. alba extracts have been reported to exert antidepressant or antistress activities in various animal models, little is known about the antidepressant-like effects of active compounds from the root bark of M. alba extracts. [15][16][17][18] In the present study, the antidepressant-like effects of sanggenon G (Fig. 1), a major phenolic compound isolated from the ethyl acetate-soluble fraction of the root bark of M. alba, were investigated in response to the forced swim test (FST) in rats. Moreover, to determine the neurobiological effects underlying the antidepressant-like activity of the sanggenon G, corticosterone responses and c-Fos immunoreactivity were evaluated in rats exposed to FST.

Determination of antidepressant activity of <i>Cyperus rotundus</i> L extract in rats

“…MAO is an important enzyme in the metabolism of a wide range of monoamine neurotransmitters, including noradrenaline, dopamine, and 5-hydroxytryptamine [11][12][13]. MAO exists in two forms, A and B. MAO A is more important than MAO B in the metabolism of the major neurotransmitter monoamines.…”

Antidepressant-Like Effects of Lindera obtusiloba Extracts on the Immobility Behavior of Rats in the Forced Swim Test

“…The FST was carried out as previously described [37]. Briefly, in the pretest session, rats were forced to swim for 15 min in a transparent Plexiglas cylinder (height 50 cm; diameter 20 cm) filled to a depth of 30 cm with water (temperature, 23–25 °C).…”

Chronopharmacological Analysis of Antidepressant Activity of a Dual-Action Serotonin Noradrenaline Reuptake Inhibitor (SNRI), Milnacipran, in Rats

“…17) This test is thus useful to evaluate antidepressant activity of various compounds and to analyze the activity's underlying mechanisms. 18) Several research groups have investigated the effects of dosing time on the activity of antidepressants in clinical settings and animal models. 19) It was proposed that in mice, the activity rhythm of serotonin transporter (SERT) in the midbrain plays a key role in the induction of the dosing time-dependent activity rhythm of the SSRI fluvoxamine.…”