A Brief Overview of the Effects of Melissa officinalis L. Extract on the Function of Various Body Organs

Melissa officinalis extract palliates redox imbalance and inflammation associated with hyperthyroidism-induced liver damage by regulating Nrf-2/ Keap-1 gene expression in γ-irradiated rats

BACKGROUND

Melissa officinalis (MO) is a well-known medicinal plant species used in the treatment of several diseases; it is widely used as a vegetable, adding flavour to dishes. This study was designed to evaluate the therapeutic effect of MO Extract against hyperthyroidism induced by Eltroxin and γ-radiation.

METHODS

Hyperthyroidism was induced by injecting rats with Eltroxin (100 µg/kg/ day) for 14 days and exposure to γ-radiation (IR) (5 Gy single dose). The hyperthyroid rats were orally treated with MO extract (75 mg/kg/day) at the beginning of the second week of the Eltroxin injection and continued for another week. The levels of thyroid hormones, liver enzymes and proteins besides the impaired hepatic redox status and antioxidant parameters were measured using commercial kits. The hepatic gene expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its inhibitor Kelch-like ECH-associated protein-1(Keap-1) in addition to hepatic inflammatory mediators including tumor necrosis factor-α (TNF- α), Monocyte chemoattractant protein-1 (MCP-1) and fibrogenic markers such as transforming growth factor-beta1 (TGF-β1) were determined.

RESULTS

MO Extract reversed the effect of Eltroxin + IR on rats and attenuated the thyroid hormones. Moreover, it alleviated hyperthyroidism-induced hepatic damage by inhibiting the hepatic enzymes' activities as well as enhancing the production of proteins concomitant with improving cellular redox homeostasis by attenuating the deranged redox balance and modulating the Nrf2/Keap-1 pathway. Additionally, MO Extract alleviated the inflammatory response by suppressing the TNF- α and MCP-1 and prevented hepatic fibrosis via Nrf2-mediated inhibition of the TGF-β1/Smad pathway.

CONCLUSION

Accordingly, these results might strengthen the hepatoprotective effect of MO Extract in a rat model of hyperthyroidism by regulating the Nrf-2/ Keap-1 pathway.

Modulation of chicken gut contractility by Melissa officinalis-ex vivo study

Melissa officinalis (lemon balm) has a long history of being used in traditional medicine for the treatment of gastrointestinal tract disorders in human thanks to its spasmolytic and stress reducing effects. These pharmacological properties have been confirmed in laboratory animals. Unfortunately, in the case of veterinary medicine, the effect of lemon balm on gut contractility has been never subjected to a detailed investigation. On the other hand, there is urgent need of new drugs that could be safely used in animals for both, causative and symptomatic treatment. In broiler chicken, one of the major health concerns includes gastrointestinal disorders with gut hypermotility. Thus, it is crucial to verify the potential utility of Melissa officinalis extract in gastrointestinal dysmotilities. The aim of the study was to analyze the effect of lemon balm extract and some of its active ingredients on chicken intestine motility. The study was performed on isolated proximal and distal jejunum preparations collected from broiler chicken which underwent routine slaughter procedure. The effect of lemon balm and 3 phenolic acids (rosmarinic, chlorogenic, and lithospermic) was verified under isometric conditions, toward spontaneous and acetylcholine (ACh)-induced smooth muscle activity. Surprisingly, M. officinalis turned out to be rather a myocontractile agent as it increased ACh-provoked contractility of proximal and distal jejunum strips and also intensified the spontaneous activity of distal jejunum. Only in the case of proximal intestine lemon balm extract diminished the force of spontaneous motoric activity up to approx. Sixty-seven percent of the control conditions. None of the tested phenolic acids displayed analog effect with the whole plant extract. In fact in the case of ACh-induced contractility, the acids had the opposite, that is, myorelaxant, effect than the extract, with a small exception of lithospermic acid in distal jejunum. Thus, it is impossible to assign one or more individual constituents to the effect of the whole Melissa officinalis extract. The obtained results do not support the use of lemon balm extract in broiler diseases which are accompanied by gut motility disturbances, including diarrhea.

Natural Products in Renal-Associated Drug Discovery

The global increase in the incidence of kidney failure constitutes a major public health problem. Kidney disease is classified into acute and chronic: acute kidney injury (AKI) is associated with an abrupt decline in kidney function and chronic kidney disease (CKD) with chronic renal failure for more than three months. Although both kidney syndromes are multifactorial, inflammation and oxidative stress play major roles in the diversity of processes leading to these kidney malfunctions. Here, we reviewed various publications on medicinal plants with antioxidant and anti-inflammatory properties with the potential to treat and manage kidney-associated diseases in rodent models. Additionally, we conducted a meta-analysis to identify gene signatures and associated biological processes perturbed in human and mouse cells treated with antioxidants such as epigallocatechin gallate (EGCG), the active ingredient in green tea, and the mushroom Ganoderma lucidum (GL) and in kidney disease rodent models. We identified EGCG- and GL-regulated gene signatures linked to metabolism; inflammation (NRG1, E2F1, NFKB1 and JUN); ion signalling; transport; renal processes (SLC12A1 and LOX) and VEGF, ERBB and BDNF signalling. Medicinal plant extracts are proving to be effective for the prevention, management and treatment of kidney-associated diseases; however, more detailed characterisations of their targets are needed to enable more trust in their application in the management of kidney-associated diseases.

Anti-inflammatory and Antioxidant Effects of Melissa officinalis Extracts: A Comparative Study

Melissa officinalis L. (MO), traditionally referred to as lemon balm, is one of the lemon-scent aromatic herbs widely used in traditional medicine due to its calming, sedative, and anti-arrhythmic effects. Furthermore, several studies have linked its therapeutic potential with its antioxidant properties. Here, we aimed to evaluate and compare the content of active components, antioxidant, and anti-inflammatory potential of three different MO extracts (MOEs), ethanolic macerate (E₁), aqueous (E₂), and ethanolic (E₃), obtained under reflux and their effects on systemic redox status after acute per os administration in vivo post-carrageenan application. The HPLC analysis revealed that the most abundant constituent in all the three extracts was rosmarinic acid (RA), with higher content in E₁ and E₃ than in E₂ (P < 0.05). The highest flavonoid content was found in the aqueous extract, especially quercetin (P < 0.05). For the carrageenan-induced paw edema model, dark agouti rats were used and divided into the groups: Control, indomethacin, E₁, E₂, and E₃ subgrouped according to applied doses: 50, 100, and 200 mg/kg. Ethanolic macerate (E₁200) and aqueous (E₂100) MOE were shown to be anti-inflammatory agents in the carrageenan paw edema model, with the most prominent edema inhibition in the sixth hour post-carrageenan (63.89% and 69.44%, respectively, vs. 76.67% in the indomethacin group). All the three extracts reduced the production of pro-oxidants H₂O₂ and TBARS post-carrageenan and increased GSH levels compared to control (P < 0.05). These data imply the possible future usage of MOEs to prevent inflammatory and oxidative stress-related diseases.

The effect of Melissa officinalis L. extract on learning and memory: Involvement of hippocampal expression of nitric oxide synthase and brain-derived neurotrophic factor in diabetic rats

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes is a systemic disease, which can cause synaptic defects in the hippocampus. Hippocampus plays a crucial role in learning and memory. Melissa officinalis L. has been used as for memory enhancement in Persian Medicine.

AIM OF THE STUDY

The aim of this study was to evaluate the impact of the hydroalcoholic extract of Melissa officinalis L. on learning and memory, considering its impact on nitric oxide synthase and brain-derived neurotrophic factor expression in the hippocampus of diabetic rats.

MATERIALS AND METHODS

Melissa officinalis L. extract was obtained by maceration method. To evaluate phenolic and flavonoid compounds of the extract, the samples were analyzed by HPLC. The animals were randomly divided into 6 groups: vehicle-treated control, Melissa officinalis-treated control (50 mg/kg), vehicle-treated diabetic, and M. officinalis-treated diabetic (25, 50, or 100 mg/kg). Diabetes was induced by streptozotocin And Melissa officinalis L. was administered for 2 weeks once diabetes was induced. Passive avoidance and Y-maze tasks were performed for learning and memory assessment. At the end of learning and memory tasks, rats were sacrificed and their hippocampus removed, lysed, and homogenized. The RNA contents were purified and then used as the template for cDNA synthesis. Real-time PCR was used to evaluate nitric oxide synthase and brain-derived neurotrophic factor genes expression.

RESULTS

Rutin was main flavonoid compound and rosmarinic acid was the main phenolic compound of the Melissa officinalis extract. Streptozotocin induced diabetes and impaired learning and memory in diabetic rats. Melissa officinalis treated-control group showed a higher alternation score in the Y-maze task and step-through latency in the passive avoidance task compared to the vehicle treated diabetic group. Melissa officinalis-treated rats showed a higher alternation score in the Y-maze task in all doses compared to the vehicle treated diabetic group (P < 0.05). In addition, in the passive avoidance task Melissa officinalis increased step-through latency (P < 0.05) but not initial latency, in all doses. Furthermore, in diabetic rats, the expression of brain-derived neurotrophic factor and nitric oxide synthase genes decreased. However, hippocampal brain-derived neurotrophic factor and nitric oxide synthase gene expression was increased in Melissa officinalis-treated rats compared to diabetic rats (P < 0.05).

CONCLUSIONS

Melissa officinalis improved learning and memory in diabetic rats, which may have occurred by increasing brain-derived neurotrophic factor and nitric oxide synthase gene expression.

Melissa officinalis L. as a Nutritional Strategy for Cardioprotection

This review aimed to provide a summary on the traditional uses, phytochemistry, and pharmacological activities in the cardiovascular system and cardiotoxicity of Melissa officinalis (MO), with the special emphasis on the protective mechanisms in different cardiovascular pathologies. MO is a perennial aromatic herb commonly known as lemon balm, honey balm, or bee balm, which belongs to Lamiaceae family. Active components are mainly located in the leaves or essential oil and include volatile compounds, terpenoid (monoterpenes, sesquiterpenes, triterpenes), and polyphenolic compounds [rosmarinic acid (RA), caffeic acid, protocatechuic acid, quercitrin, rhamnocitrin, luteolin]. For centuries, MO has been traditionally used as a remedy for memory, cognition, anxiety, depression, and heart palpitations. Up until now, several beneficial cardiovascular effects of MO, in the form of extracts (aqueous, alcoholic, and hydroalcoholic), essential oil, and isolated compounds, have been confirmed in preclinical animal studies, such as antiarrhythmogenic, negative chronotropic and dromotropic, hypotensive, vasorelaxant, and infarct size-reducing effects. Nonetheless, MO effects on heart palpitations are the only ones confirmed in human subjects. The main mechanisms proposed for the cardiovascular effects of this plant are antioxidant free radical-scavenging properties of MO polyphenols, amelioration of oxidative stress, anti-inflammatory effects, activation of M2 and antagonism of β1 receptors in the heart, blockage of voltage-dependent Ca²⁺ channels, stimulation of endothelial nitric oxide synthesis, prevention of fibrotic changes, etc. Additionally, the main active ingredient of MO-RA, per se, has shown substantial cardiovascular effects. Because of the vastness of encouraging data from animal studies, this plant, as well as the main ingredient RA, should be considered and investigated further as a tool for cardioprotection and adjuvant therapy in patients suffering from cardiovascular diseases.

Melissa officinalis L. Aqueous Extract Exerts Antioxidant and Antiangiogenic Effects and Improves Physiological Skin Parameters

Melissa officinalis (MO) is a medicinal plant well-known for its multiple pharmacological effects, including anti-inflammatory, anticancer and beneficial effects on skin recovery. In this context, the present study was aimed to investigate the in vitro and in vivo safety profile of an MO aqueous extract by assessing cell viability on normal (HaCaT-human keratinocytes) and tumor (A375-human melanoma) cells and its impact on physiological skin parameters by a non-invasive method. In addition, the antioxidant activity and the antiangiogenic potential of the extract were verified. A selective cytotoxic effect was noted in A375 cells, while no toxicity was noticed in healthy cells. The MO aqueous extract safety profile after topical application was investigated on SKH-1 mice, and an enhanced skin hydration and decreased erythema and transepidermal water loss levels were observed. The in ovo CAM assay, performed to investigate the potential modulating effect on the angiogenesis process and the blood vessels impact, indicated that at concentrations of 100 and 500 µg/mL, MO aqueous extract induced a reduction of thin capillaries. No signs of vascular toxicity were recorded at concentrations as high as 1000 μg/mL. The aqueous extract of MO leaves can be considered a promising candidate for skin disorders with impaired physiological skin parameters.

A Comparative Study of Melissa officinalis Leaves and Stems Ethanolic Extracts in terms of Antioxidant, Cytotoxic, and Antiproliferative Potential

Melissa officinalis L. has attracted an increased interest in recent years due to its multiple pharmacological effects. This study aimed to compare two M. officinalis ethanolic extracts, obtained from leaves and stems, with regard to their antioxidant activity, total phenolic content, and cytotoxic effects. M. officinalis ethanolic extracts showed a very good antioxidant activity in the DPPH test, correlated with the content in total phenols: higher in the case of M. officinalis from leaves extract (32.76 mg GAE/g) and lower for M. officinalis from stems extract (8.4 mg GAE/g). The lemon balm extracts exerted a cytotoxic effect on breast cancer cells (MDA-MB-231) even at low concentrations (100 μg/mL), whereas, in the case of healthy HaCat cells, M. officinalis leaves extract only displayed cytotoxicity at much higher concentrations (500 and 1000 μg/mL) and M. officinalis stems extracts were highly cytotoxic (starting at 100 μg/mL). In addition, the extracts exerted inhibitory effects on cell migration and proliferation. These results provide information that confirms the high potential of M. officinalis as a source of chemopreventive agents. Moreover, these data can be considered a solid background for further in vivo studies involving mice bearing breast tumors.