Antidepressant-like effects of the ethyl acetate soluble fraction of the root bark of Morus alba on the immobility behavior of rats in the forced swim test

Medicinal Plants in the Treatment of Depression: Evidence from Preclinical Studies

Medicinal plants and their extracts are natural remedies with enormous potential for treating various diseases, including depression and anxiety. In the case of depression, hundreds of plants have traditionally been used in folk medicine for generations. Different plant extracts and natural products have been analyzed as potential antidepressant agents with validated models to test for antidepressant-like effects in animals, although other complementary studies have also been employed. Most of these studies focus on the possible mediators implicated in these potential effects, with dopamine, serotonin, and noradrenaline being the principal neurotransmitters implicated, both through interference with receptors and with their metabolism by monoamino oxidases, as well as through neuro-endocrine and neuroprotective effects. There are approximately 650 reports of antidepressant-like medicinal plants in PubMed; 155 of them have been compiled in this review, with a relevant group yielding positive results. Saffron and turmeric are the most relevant species studied in both preclinical and clinical studies; St. John's wort or kava have also been tested extensively. To the best of our knowledge, no review to date has provided a comprehensive understanding of the biomolecular mechanisms of action of these herbs or of whether their potential effects could have real benefits. The purpose of this narrative review is to provide an update regarding medicinal plants from the year 2000 to the present to examine the therapeutic potential of these antidepressant-like plants in order to contribute to the development of new therapeutic methods to alleviate the tremendous burden that depression causes worldwide.

Effects of Mulberry on The Central Nervous System: A Literature Review

Background

Mulberry, including several species belonging to genus Morus, has been widely used as a traditional medicine for a long time. Extracts and active components of mulberry have many positive neurological and biological effects and can become potential candidates in the search for new drugs for neurological disorders.

Objectives

We aimed to systematically review the medical literature for evidence of mulberry effects on the central nervous system.

Methods

We conducted a systematic search in nine databases. We included all in vivo studies investigating the effect of mulberry on the central nervous system with no restrictions.

Results

We finally included 47 articles for quality synthesis. Our findings showed that mulberry and its components possessed an antioxidant effect, showed a reduction in the cerebral infarct volume after stroke. They also improved the cognitive function, learning process, and reduced memory impairment in many animal models. M. alba and its extracts ameliorated Parkinson's disease-like behaviors, limited the complications of diabetes mellitus on the central nervous system, possessed anti-convulsant, anti-depressive, and anxiolytic effects.

Conclusion

Mulberry species proved beneficial to many neurological functions in animal models. The active ingredients of each species, especially M. alba, should be deeper studied for screening potential candidates for future treatments.

Morus alba L. Diminishes visceral adiposity, insulin resistance, behavioral alterations via regulation of gene expression of leptin, resistin and adiponectin in rats fed a high-cholesterol diet

Ethanolic extract of leaves of Morus alba L. (M. alba), known as white mulberry, was orally administered (100 mg/kg b.wt) for 8 weeks to female Wistar rats that were fed a high-cholesterol diet (HCD), to investigate the potential of M. alba leaves in attenuation of obesity, dyslipidemia, insulin resistance, and deficits in mood, cognitive as well as motor activity that are linked to the adipokines secretions of visceral adipose tissue. Results showed that M. alba diminished body weight gain, hypercholesterolemia, hypertriglyceridemia, atherogenic (AI) & coronary artery indices (CRI), and ameliorated glucose level and insulin resistance index in rats on HCD, compared with untreated HCD rats. Moreover, M. alba administration significantly decreased serum leptin and resistin contents as well as their mRNA expression in visceral adipose tissue, but significantly increased serum adiponectin level, and its mRNA expression in visceral adipose tissue in rats fed on HCD, compared to those in untreated HCD group. Regarding behavioral alterations, M. alba attenuated motor deficit, declined memory, depression and anxiety-like behavior, as well in rats on HCD, compared to that noticed in untreated HCD rats. The current data showed that serum leptin and resistin showed a positive correlation with and body weight gain, triglycerides (TG), AI as well as CRI, but showed a negative correlation with exploration, declined memory, depression- and anxiety-like behavior. Conversely, serum adiponectin showed a negative correlation with and body weight gain, TG, AI as well as CRI, but showed a positive correlation with locomotor activity, exploration, declined memory, and depression- and anxiety-like behavior. In conclusion, M. alba leaves supplementation could attenuate adiposity, insulin resistance behavioral deficits via down-regulation of regulation of gene expression of leptin, resistin, but up-regulation of adiponectin gene expression in the visceral adipose tissue of rats fed a high-cholesterol diet.

Comparison of Different Strains of Agrobacterium rhizogenes for Hairy Root Induction and Betulin and Betulinic Acid Production in Morus alba

Three Agrobacterium rhizogenes strains were tested for their ability to transform the plant Morus alba L. and to induce production of the secondary metabolites betulin and betulinic acid. All the tested strains of A. rhizogenes (R1601, LBA9402 and R1000) were able to induce hairy root formation in leaf tissue explants. Strain LBA9402 had the highest rate of infection (92.7% ± 8.8%), whereas strain R1601 had the lowest rate (87.4% ± 9.3%). The highest number of hairy roots per explant (5.6 ± 0.5) and the greatest root length (2.4 ± 0.2 mm) were obtained with strain LBA9402. We also evaluated dry weight (a measure of growth) and betulin and betulinic acid production in hairy roots and found that the highest growth (167.8 ± 14.5 mg/flask) occurred after infection with strain LBA9402. Furthermore the highest production of betulin (5.4 ± 0.4 mg/g dry weight) and betulinic acid (2.3 ± 0.2 mg/g dry weight) was noted using strain LBA9402. Among three elicitors, yeast extract showed the highest induction of betulin production (8.7 ± 0.4 mg/g) and silver nitrate induced the highest yield of betulinic acid (4.1 ± 0.2 mg/g). Our study showed that A. rhizogenes strain LBA9402 was the most effective of the three tested strains for production of transformed root cultures and betulin and betulinic acid.

Root bark of Morus alba ameliorates the depressive-like behaviors in diabetic rats

Diabetes-induced depression is one of the severe chronic complications of diabetes mellitus. Up to now, there are only a few effective medicines to prevent or manage the co-morbidity of diabetes and depression. The present study was to investigate the effect of root bark of Morus alba (RBM) on depressive-like behaviors in the diabetic rats established by a high fat diet and a low dose of streptozotocin. Depressive-like behaviors were measured by the open field test, locomotor activity test and forced swimming test. Plasma glucose and lipid parameters were also measured. Expression of Brain-derived neurotrophic factor (BDNF) and phosphorylation of extracellular signal-regulated kinase (ERK) and Akt in the prefrontal cortex (PFC) were assessed. The results showed that a 4-week administration of RBM (10g/kg, ig) significantly reversed the depressive-like behaviors. BDNF expression and phosphorylation of ERK and Akt were increased in the PFC following RBM treatment in the diabetic rats. The data demonstrated that RBM could improve the depressive-like behaviors induced by diabetes, suggesting a therapeutic potential of RBM for the diabetes-associated depression.

Three New Isoprenylated Flavonoids from the Root Bark of Morus alba

Phytochemical investigation of the root bark of Morus alba has led to the isolation and identification of three new isoprenylated flavonoids, namely sanggenon U (1), sanggenon V (2), and sanggenon W (3), along with four known isoprenylated flavonoids: euchrenone a₇ (4), sanggenon J (5), kuwanon E (6), and kuwanon S (7). All compounds were isolated by repeated silica gel (SiO₂), octadecyl SiO₂ (ODS), and Sephadex LH-20 open column chromatography. The structure of the compounds were determined based on spectroscopic analyses, including nuclear magnetic resonance (NMR), mass spectrometry (MS), circular dichroism (CD), and infrared (IR). In addition, compounds 1-4 were isolated for the first time from the root bark of M. alba in this study.

Enhanced anti-immobility effects of Sanggenon G isolated from the root bark of Morus alba combined with the α2-antagonist yohimbine in the rat forced swim test

In this study, we aimed to determine whether Sanggenon G, an active compound isolated from the root bark of Morus alba, exhibited enhanced anti-immobility activity with the addition of the α2-antagonist yohimbine in rats subjected to forced swim test (FST)-induced depression. Fluoxetine (a selective serotonin reuptake inhibitor) treatment in rats reduced the immobility time, and pretreatment with yohimbine significantly enhanced the antidepressant-like behavior of fluoxetine at 5, 10 and 20 mg/kg. Similarly, Sanggenon G significantly decreased the immobility time, reducing immobility by a maximum of 43.9 % when treated at a dose of 20 mg/kg. Furthermore, pretreatment with yohimbine significantly enhanced the antidepressant-like behavior of Sanggenon G at 5 and 10 mg/kg. Our findings suggest that the antidepressant-like effect of Sanggenon G could be facilitated by concomitant use of the α2-antagonist. Further studies are needed to evaluate the potential of Sanggenon G as an alternative therapeutic approach for the treatment of depression.

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

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 (FST)-induced depression. Acute treatment of rats with sanggenon G (30 mg/kg, intraperitoneally (i.p.)) significantly reduced immobility time and increased swimming time without any significant change in climbing. Rats treated with sanggenon G also exhibited a decrease in the limbic hypothalamic-pituitary-adrenal (HPA) axis response to the FST, as indicated by attenuation of the corticosterone response and decreased c-Fos immunoreactivity in the hypothalamic paraventricular nucleus (PVN). In addition, the antidepressant-like effects of sanggenon G were significantly inhibited by WAY100635 (1 mg/kg, i.p.; a selective 5-hydroxytryptamine1A (5-HT1A) receptor antagonist), but not SCH23390 (0.05 mg/kg, i.p.; a dopamine D1 receptor antagonist). Our findings suggested that the antidepressant-like effects of sanggenon G were mediated by an interaction with the serotonergic system. Further studies are needed to evaluate the potential of sanggenon G as an alternative therapeutic approach for the treatment of depression.