The Health Beneficial Properties of Rhodomyrtus tomentosa as Potential Functional Food

Genomic analysis based on chromosome-level genome assembly reveals Myrtaceae evolution and terpene biosynthesis of rose myrtle

BACKGROUND

Rose myrtle (Rhodomyrtus tomentosa (Ait.) Hassk), is an evergreen shrub species belonging to the family Myrtaceae, which is enriched with bioactive volatiles (α-pinene and β-caryophyllene) with medicinal and industrial applications. However, the mechanism underlying the volatile accumulation in the rose myrtle is still unclear.

RESULTS

Here, we present a chromosome-level genomic assembly of rose myrtle (genome size = 466 Mb, scaffold N50 = 43.7 Mb) with 35,554 protein-coding genes predicted. Through comparative genomic analysis, we found that gene expansion and duplication had a potential contribution to the accumulation of volatile substances. We proposed that the action of positive selection was significantly involved in volatile accumulation. We identified 43 TPS genes in R. tomentosa. Further transcriptomic and TPS gene family analyses demonstrated that the distinct gene subgroups of TPS may contribute greatly to the biosynthesis and accumulation of different volatiles in the Myrtle family of shrubs and trees. The results suggested that the diversity of TPS-a subgroups led to the accumulation of special sesquiterpenes in different plants of the Myrtaceae family.

CONCLUSIONS

The high quality chromosome-level rose myrtle genome and the comparative analysis of TPS gene family open new avenues for obtaining a higher commercial value of essential oils in medical plants.

Potential applications of Rhodomyrtus tomentosa leaf extract as natural anti-staphylococcal additive in food systems: Efficacy and in vivo safety evaluation

This work aimed to explore the potential use of Rhodomyrtus tomentosa ethanol leaf extract (RTEL) as an alternative food preservative agent for controlling the growth of Staphylococcus aureus. Antibacterial activities against food-isolated S. aureus were performed using disc diffusion and broth microdilution assays, followed by evaluating in vivo subacute oral toxicity of the extract. Salad dressing was used as a food model to study bactericidal properties and consumer acceptability. RTEL remarkably inhibited S. aureus with minimum inhibitory concentrations (MICs) ranging from 7.81-62.5 µg/mL. Repeated oral doses (5, 50, and 300 mg/kg RTEL) for 28 days did not affect any of the measured toxicity parameters. The no-observed-adverse-effect-level (NOAEL) of RTEL was noted as more than 300 mg/kg body weight/day. The utilization of RTEL (12.5 mg/mL) in the vinaigrette salad dressing did not affect the consumer acceptability of the product, remarkably killed the pathogen within 3-9 h of exposure. The results indicated that RTEL is safe and effective as a natural anti-staphylococcal controlling agent that could be utilized in food systems. Further work is required on the effects of enterotoxin production, an important virulence factor of S. aureus responsible for food-borne disease.

Analysis of the Rhodomyrtus tomentosa mitochondrial genome: Insights into repeat-mediated recombination and intra-cellular DNA transfer

Plant mitochondrial genomes participate in encoding proteins crucial to the major producers of ATP in the cell and replication and heredity of their own DNA. The sequences and structure of the plant mitochondrial genomes profoundly impact these fundamental processes, and studies of plant mitochondrial genomes are needed. We reported the complete sequences of the Rhodomyrtus tomentosa mitochondrial genome here, totaling 400,482 bp. Nanopore ONT reads and PCR amplification provided evidence for recombination mediated by the eight repeat pairs for the R. tomentosa mitochondrial genome. Thirty-eight genes were identified in the R. tomentosa mitochondrial genome. Comparative analyses of the mitochondrial genome and plastome and PCR amplification suggest that five fragments of mitochondrial plastid DNA were unfunctional sequences resulting from intracellular gene transfer. Phylogenetic analysis based on each and all of the 27 mitochondrial protein-coding genes of nine Myrtales species revealed that R. tomentosa always clustered with other species of Myrtaceae. This study uncovered the enormous complexity of the R. tomentosa mitochondrial genome, the active repeat-mediated recombinations, the presence of mitochondrial plastid DNAs, and the topological incongruence of Myrtales among the single-gene trees.

Rhodomyrtus tomentosa as a new anticancer molecular strategy in breast histology via Her2, IL33, EGFR, and MUC1

The prevalence of breast cancer among patients in Indonesia is significant. Indonesian individuals maintain the belief that cancer cannot be cured alone by pharmaceuticals and treatment; herbal remedies must be used in conjunction. Rhodomyrtus tomentosa, also known as Haramonting, is an indigenous Indonesian medicinal plant renowned for its copious antioxidant properties. The objective of study was to assess the impact of haramonting on breast cancer by examining the expression of various biomarker proteins associated with breast cancer. Haramonting was administered to breast cancer model mice at different doses over a period of 30 days. Subsequently, blood and breast samples were obtained for immunohistochemistry and enzyme-linked immunosorbent assays (ELISA). Authors have discovered that there has been a notable rise in the proliferation of epithelial cells in the duct lobes, resulting in the formation of ducts and lobules. Additionally, the researchers discovered that the breasts exhibited distinct clinical and histological alterations. Haramonting possesses the capacity to restore the concentrations of malondialdehyde (MDA) and superoxide dismutase (SOD) to normal levels in the blood serum of rats afflicted with cancer. The histopathological analysis of the breast tissue revealed elevated levels of Her2, IL33, EGFR, and MUC1. The authors also discovered a notable increase in the growth of epithelial cells, with two or more layers of cells reaching towards the centre of the duct. The size of the epithelial cells exhibits variability; however, this state ameliorates with the administration of a dosage of 300 mg/kgBW of this botanical specimen. This study proposes that Haramonting may be effective in treating breast cancer.

Rhodomyrtus tomentosa (Aiton) Hassk. (haramonting) protects against allethrin-exposed pulmo damage in rats: mechanistic interleukins

Inhaling Allethrin (C19H26O3) may induce oxidative stress in lung cells by causing the formation of free radi-cals. Interleukins (IL) are a group of secreted cytokines or proteins and signaling molecules initially produced as an immune response by leukocytes. Rhodomyrtus tomentosa (Aiton) Hassk. (haramonting) contains antioxidants that may prevent lung damage induced by allethrin-containing electric mosquito repellents. In this study, six groups of rats were exposed to allethrin via an electric mosquito repellent, including positive, negative, and comparison control groups and three groups were administered Rhodomyrtus tomentosa (Aiton) Hassk at 100 mg/kg BW, 200 mg/kg BW, and 300 mg/kg BW. After 30 days, the pulmonary tissue and the blood were taken for immunohisto-chemical and ELISA analysis. The accumulation of inflammatory cells causes the thickening of the alveolar wall structures. Injuries were more prevalent in the A+ group than in the other groups. The connection between the alveoli and blood capillaries, which can interfere with alveolar gas exchange, is not regulated, and the lu-minal morphology is aberrant, causing damage to the alveolar epithelial cells. Exposure to electric mosquito coils containing allethrin can increase the expression of interleukin-1, interleukin-8, interleukin-9, and interleu-kin-18 in blood serum and tissues while decreasing the expression of interleukin-6 and interleukin-10. Like the Vitamin C group, Rhodomyrtus tomentosa can increase alveolar histological alterations by decreasing the ex-pression of IL-1β, IL-8, IL-9, and IL-18 while increasing IL-6 and IL-10. So that this plant can be developed in the future as a drug to prevent lung harm from exposure.

A Novel Antibiotic, Rhodomyrtone: Pharmacokinetic Studies in a Murine Model and Optimization and Validation of High-Performance Liquid Chromatographic Method for Plasma Analysis

Rhodomyrtone has indisputable and undeniable potential as a new antibiotic for antibiotic-resistant Gram-positive bacteria. Therefore, the main objective of this study was to determine the pharmacokinetics profiles of orally administered rhodomyrtone in rats. A reverse-phase HPLC-UV method was developed, optimized and validated for the analysis of rhodomyrtone concentrations in rat plasma. The retention time of papaverine and rhodomyrtone was 3.928 and 5.937 min, with no interference with the excipients used. The lower limit of quantification (LLOQ) of rhodomyrtone in the plasma sample was 0.04 μg/mL, the accuracy of rhodomyrtone at the LLOQ level ranged from 93.64 to 106.36%, precision was 6.59%, 80-120% for accuracy and <20% CV for precision. The calibration curve was linear at concentrations ranging from 0.04 to 128 µg/mL with a correlation coefficient (r) value of equal to or greater than 0.999. Sprague Dawley rats received a single dose of rhodomyrtone at 50 and 100 mg/kg. Blood samples were collected from tail veins. The peak plasma concentration was observed at 2 h, and the area under the curve of rhodomyrtone at 50 mg/kg and 100 mg/kg was 3.41 ± 1.04 and 7.82 ± 1.53 μg·h/mL, respectively. The results demonstrated linear pharmacokinetics characteristics at the studied dosage range. The plasma concentration of rhodomyrtone was above the minimal inhibition concentrations of several common pathogenic bacteria of medical importance. The proposed HPLC-UV method is fast, cost-effective, reliable and reproducible, and it is proposed for the routine analysis of rhodomyrtone.

Genomic and Transcriptional Profiling Analysis and Insights into Rhodomyrtone Yield in Rhodomyrtus tomentosa (Aiton) Hassk

Rhodomyrtus tomentosa is a source of a novel antibiotic, rhodomyrtone. Because of the increasing industrial demand for this compound, germplasm with a high rhodomyrtone content is the key to sustainable future cultivation. In this study, rhodomyrtone genotypes were verified using the plastid genomic region marker matK and nuclear ribosomal internal transcribed spacer ITS. These two DNA barcodes proved to be useful tools for identifying different rhodomyrtone contents via the SNP haplotypes C569T and A561G, respectively. The results were correlated with rhodomyrtone content determined via HPLC. Subsequently, R. tomentosa samples with high- and low-rhodomyrtone genotypes were collected for de novo transcriptome and gene expression analyses. A total of 83,402 unigenes were classified into 25 KOG classifications, and 74,102 annotated unigenes were obtained. Analysis of differential gene expression between samples or groups using DESeq2 revealed highly expressed levels related to rhodomyrtone content in two genotypes. semiquantitative RT-PCR further revealed that the high rhodomyrtone content in these two genotypes correlated with expression of zinc transporter protein (RtZnT). In addition, we found that expression of RtZnT resulted in increased sensitivity of R. tomentosa under ZnSO4 stress. The findings provide useful information for selection of cultivation sites to achieve high rhodomyrtone yields in R. tomentosa.

Histological analysis of TGFβ1 and VEGFR expression in cervical carcinoma treated with Rhodomyrtus tomentosa

Cervical carcinoma is one of the most common malignant carcinomas around the world, including Indonesia. Rhodomyrtus tomentosa is an herbal medicine that is often used in Asia as a therapeutic agent to stop cancer metastases. The process of neoangiogenesis in cervical cancer depends on VEGFR activity. Increased TGFβ1 production is also linked to cervical cancer, suggesting that gene inactivation contributes to the emergence of cervical carcinoma.

Group C- was the control group, Group C+ was the cancer model group, CER100 was the group of rats with cancer + 100 mg/kg body weight (BW) of R. tomentosa, CER200 was the group of rats with cancer + 200 mg/kg BW of R. tomentosa, and CER400 was the group of rats with cancer + 400 mg/kg BWR. tomentosa. Rats were dissected after administration of R. tomentosa for 30 days. Immunohistochemical staining of the cervical tissue was performed with TGFβ1 and VEGFR antibodies. VEGFR expression was significantly different from TGFβ1 expression (p &lt; 0.01). The highest expression was observed at the lowest dose of R. tomentosa (100 mg/kg BW), and the lowest expression was observed at 200 and 400 mg/kg BW. The administration of R. tomentosa can repair tissue damage and decrease the expression of TGFβ1 and VEGFR via histopathological parameters, indicating the importance of the activity of these proteins in the development of neoangiogenesis in cervical cancer.

Insulin Secretory Actions of Ethanol Extract of Eucalyptus citriodora Leaf, including Plasma DPP-IV and GLP-1 Levels in High-Fat-Fed Rats, as Well as Characterization of Biologically Effective Phytoconstituents

Due to the numerous adverse effects of synthetic drugs, researchers are currently studying traditional medicinal plants to find alternatives for diabetes treatment. Eucalyptus citriodora is known to be used as a remedy for various illnesses, including diabetes. This study aimed to explore the effects of ethanol extract of Eucalyptus citriodora (EEEC) on in vitro and in vivo systems, including the mechanism/s of action. The methodology used involved the measurement of insulin secretion from clonal pancreatic β-cells, BRIN BD11, and mouse islets. Other in vitro systems further examined EEEC’s glucose-lowering properties. Obese rats fed a high-fat-fed diet (HFF) were selected for in vivo evaluation, and phytoconstituents were detected via RP-HPLC followed by LC-MS. EEEC induced insulin secretion in a concentration-dependent manner with modulatory effects, similar to 1 µM glucagon-like peptide 1 (GLP-1), which were partly declined in the presence of Ca^2+-channel blocker (Verapamil), K_ATP-channel opener (Diazoxide), and Ca²⁺ chelation. The insulin secretory effects of EEEC were augmented by isobutyl methylxanthine (IBMX), which persisted in the context of tolbutamide or a depolarizing concentration of KCl. EEEC enhanced insulin action in 3T3-L1 cells and reduced glucose absorption, and protein glycation in vitro. In HFF rats, it improved glucose tolerance and plasma insulin, attenuated plasma DPP-IV, and induced active GLP-1 (7-36) levels in circulation. Rhodomyrtosone B, Quercetin-3-O-β-D-glucopyranoside, rhodomyrtosone E, and quercitroside were identified as possible phytoconstituents that may be responsible for EEEC effects. Thus, these findings revealed that E. citriodora could be used as an adjunct nutritional supplement to manage type 2 diabetes.

Functional food: complementary to fight against COVID-19

Background

The novel coronavirus has embarked on a global pandemic and severe mortality with limited access for its treatments and medications. For the lack of time, research, and enough efficacy, most vaccines are underdeveloped or unreachable to society. However, many recent studies suggest various alternative, complementary remedies for COVID-19, which are functional foods. This review provides an overview of how functional foods can play a great role through modulating the host immune system, generating antiviral activities, and synthesizing biologically active agents effective against the coronavirus.

Main body

This review article summarizes the natural defense mechanisms in tackling SARS-CoV-2 alongside conventional therapeutic options and their corresponding harmful side effects. By analyzing bioactive components of functional foods, we have outlined its different contributions to human health and its potential immunomodulatory and antiviral properties that can enhance resistivity to viral infection. Moreover, we have provided a myriad of accessible and cost-effective functional foods that could be further investigated to target specific key symptoms of COVID-19 infections. Finally, we have found various functional foods with potent bioactive compounds that can inhibit or prevent COVID-19 infections and disease progression.

Short conclusion

Numerous functional foods can help the body fight COVID-19 through several mechanisms such as the reduced release of pro-inflammatory cytokines, reduced expression of ACE2 receptors in cells, and inhibiting essential enzymes in SARS-CoV-2.

Antidiabetic, cytotoxic and antioxidant activities of Rhodomyrtus tomentosa leaf extracts

As part of our project on exploring Indonesian medicinal plants for antidiabetic and anticancer agents, this study was conducted to investigate the total phenolic and flavonoid contents, and antioxidant, cytotoxic and antidiabetic properties of R. tomentosa leaf extracts. The antioxidant activity was tested using DPPH, ABTS, and FRAP methods. In vitro cytotoxic assay was performed against MCF-7, HeLa, A549, and B16 cancer cell lines. The in vitro antidiabetic testing was determined using α-glucosidase and α-amylase inhibitory evaluation, while STZ-induced diabetic rats were used for in vivo study. The highest values of total phenolic (191.97 ± 0.19 mg GAE g⁻¹) and flavonoid (29.11 ± 0.05 mg QE g⁻¹) contents were recorded in methanolic extract. This extract also showed the highest DPPH and ABTS activities with IC₅₀ values of 7.79 ± 0.03 and 4.03 ± 0.02 μg mL⁻¹, respectively, as well as the highest FRAP activity with a value of 64.05 ± 0.54 μM Fe²⁺ g⁻¹. The methanol extract had cytotoxicity against MCF-7, HeLa, A549, and B16 cancer cell lines with IC₅₀ values of 123.49 ± 0.79, 28.28 ± 0.17, 168.88 ± 1.14, and 42.44 ± 0.18 μg mL⁻¹, respectively. In vitro antidiabetic evaluation indicated that the MeOH extract inhibited α-glucosidase and α-amylase with IC₅₀ values of 45.73 ± 1.06 and 41.31 ± 1.12 μg mL⁻¹, respectively. A dose of 400 mg kg⁻¹ body weight of the MeOH extract reduced rats' blood glucose rate and serum blood glucose by 48.51% and 17.73%, respectively after 15 days of treatment. Taken together, these findings suggested that the methanolic extract of R. tomentosa leaves can be used as a potential source of antioxidant, cytotoxic, and antidiabetic agents.

As part of our project on exploring Indonesian medicinal plants for antidiabetic and anticancer agents, this study was conducted to investigate the total phenolic and flavonoid contents, and antioxidant, cytotoxic and antidiabetic properties of R. tomentosa leaf extracts.

Anti-Inflammatory and Anti-Remodelling Potential of Ethanol Extract Rhodomyrtus Tomentosa in Combination of Asthma and Coal Dust Models

BACKGROUND

Combination of asthma and coal dust is a chronic and recurring airway disease related to inflammation cell activation. The Rhodomyrtus tomentosa flowering plants native to South Kalimantan exhibit a broad therapeutic potential, like anti-inflammatory and anti-remodelling properties. This study aims to analyze the effect of ethanol extract of R. tomentosa leaves (EERTL) nebulizer on the number of inflammatory cells and histomorphometry of lung tissue in a mice-like model of a combination of asthma and coal dust.

METHODS

The 24 BALB/c mice were divided into four treatment groups (n= 6 per group), were sensitized with normal saline (K), OVA + coal dust (P1), OVA + coal dust + salbutamol (P2), and OVA + coal dust + EERTL (P3). Eosinophil cells, neutrophils, lymphocytes, epithelial thickness, smooth muscle, fibrosis subepithelial bronchioles, and the number of goblet cells as indicators of anti-inflammatory and anti-remodelling airways.

RESULTS

The number of eosinophils, neutrophils, and lymphocytes cells are given salbutamol or EERTL was significantly lower than the OVA-sensitized and coal dust exposure group only. There are meaningful differences in the average thickness of the epithelium, smooth muscle, and subepithelial fibrosis of bronchiolus. The histopathology picture of goblet cells showed an increase in the number and size (hyperplasia) in OVA-sensitized and coal dust exposure compared to another group.

CONCLUSION

It was concluded that the EERTL nebulizer could reduce inflammatory cells and remodelling process from bronchoalveolar lavage in the mice combination of asthma and coal dust models.

Potential of karamunting (Rhodomyrtus tomentosa) fraction against kidney damage in diabetic rats

Introduction: Karamunting (Rhodomyrtus tomentosa) is Indonesian native plant that contains high anti-oxidant compounds with the potential to suppress oxidative stress activity in cells. This study is the first research to specifically explore the role of the karamunting fraction in protecting kidney damage due to the formation of AGEs in the renal glomerulus in diabetes mellitus.

Objective: This study aims to assess the impact of karamunting on blood glucose profile, HbA1c, insulin profile and kidney condition (AGEs expression, TNF-α and kidney histology) in diabetic rats.

Methods: The karamunting extraction process was carried out by maceration with ethanol. Induction of diabetes mellitus was carried out using streptozotocin. Thirty male rats (Rattus norvegicus), Wistar strain weighing between 200–250 grams were the subject in this study. HbA1c, insulin, TNF-α, AGEs levels were evaluated in the kidney tissue. Histological assessment of the kidney was carried out.

Results: Karamunting can improve blood glucose levels in diabetic rats. This improvement in blood glucose levels causes an improvement in the level of HbA1c. Administration of karamunting fraction can prevent AGEs deposition in renal tissue, which in turn will inhibits the inflammation and prevents further damage of kidneys.

Conclusion: Karamunting fraction can improve blood glucose regulation so that it can prevent further damage and complications of kidney organs in diabetic rats.

Antimicrobial Activity of Methanolic and Aqueous Extract of Rhodomyrtus tomentosa Leaves against Staphylococcus aureus and Escherichia coli

Food poisoning is one of the riskiest illnesses caused by an organism like bacteria, viruses and parasites, which can contaminate food at any stage of food production. Most reports are associated with bacterial contamination through the food preparation process. Researcher nowadays attempts to discover a safer agent to use in food preparation as a food preservative agent. Thus, the potential of Rhodomyrtus tomentosa leaves as an antimicrobial agent was explored in this study. It was tested against two bacteria which are Staphylococcus aureus (gram-positive) and Eschericia coli (gram-negative). Antimicrobial activity of methanol and aqueous R. tomentosa leaves extract was compared using gram staining, bacterial identification, antimicrobial sensitivity testing (AST), minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and statistical analysis. The disc diffusion technique was used for AST where the mean area of inhibition methanol and aqueous extract against S. aureus was 18 mm and 16 mm respectively, whereas there was no area of inhibition for E. coli. MIC was done to determine the minimum concentration of the extract needed to inhibit the bacteria. After that, MBC was performed to confirm the previous MIC result. Statistical analysis was done by conduct it through SPSS software program. Then, the result for S. aureus is obtained from finding its p-value. Statistically, a significant difference between the two bacteria was analyzed by using independent t-test. A result of p-value less than 0.05 was considered significantly different as one another. Statistical analysis showed no significant difference between methanol and aqueous extract on antimicrobial activity. In conclusion, both aqueous and methanol leaves R. tomentosa yielded similar antibacterial activity which susceptible to S. aureus and can be used safely toward foodborne pathogen.

The Biomimetic Total Syntheses of the Antiplasmodial Tomentosones A and B

The first biomimetic total syntheses of natural phloroglucinols tomentosones A and B and their analogues have been accomplished. The synthetic strategy primarily referred to the potential biosynthetic precursors and their possible sequence of segments assembly by chemological evolution of the structural entities and enabled rapid access of the titled compounds in a practical fashion.

Rhodomyrtus tomentosa Fruit Extract and Skin Microbiota: A Focus on C. acnes Phylotypes in Acne Subjects

Knowing that Rhodomyrtus tomentosa is known to have antibacterial effects, this study investigated the skin microbiota with a focus on Cutibacterium acnes (C. acnes) phylotypes in subjects with acne, and determined microbiota changes after 28 days of treatment with berries Rhodomyrtus tomentosa as an active ingredient (RT). Skin swabs from seventeen acne subjects were collected and the skin microbiome was analyzed using 16S rRNA gene sequencing. A culture-independent next-generation sequencing (NGS)-based SLST (single-locus sequence typing) approach was aimed at evaluating RT extract effects on C. acnes phylotype repartition. Clinical evaluations (lesion counts) were performed at baseline (D0) and after 28 days (D28) of twice-daily application of the RT active ingredient. We determined: (1) the skin microbiota at D0 was dominated by Actinobacteria followed by Firmicutes and Proteobacteria; (2) at the genus level, Cutibacterium was the most abundant genus followed by Staphylococcus and Corynebacterium; (3) C. acnes was the major species in terms of mean abundance, followed by Staphylococcus epidermidis (S. epidermidis) and Staphylococcus hominis (S. hominis); and (4) phylotype IA1 was most represented, with a predominance of SLST type A1, followed by phylotypes II, IB, IA2, IC, and III. After 28 days of RT extract treatment, phylotype repartition were modified with a decrease in abundance (approximately 4%) of phylotype IA1 and an increase in phylotype II and III. Cutibacterium granulosum (C. granulosum) abundance also decreased. Reduction of retentional and inflammatory lesions was also noted only after RT treatment; thus, RT extract acts as a microbiota-regulating agent.

The role of myricetin from Rhodomyrtus tomentosa (Aiton) Hassk fruits on downregulation of FcɛRI-mediated mast cell activation

Rhodomyrtus tomentosa was reported to contain various bioactive metabolites, especially phenolic compounds. In the present study, the suppressive activity of phenolic compound from R. tomentosa fruits on mast cell activation was investigated in vitro. The result showed that myricetin was isolated from R. tomentosa fruits and its characterization was identified by nuclear magnetic resonance spectroscopy. Notably, myricetin was found to be effective in inhibition of mast cell degranulation by attenuating the release of β-hexosaminidase and the elevation of intracellular calcium. Moreover, myricetin exhibited inhibitory effect on the production of IL-4 and Tumor necrosis factor alpha (TNF-α) in a concentration-dependent manner. Furthermore, high antioxidant activity of myricetin due to scavenging 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ABTS⁺ radicals was also evidenced. Notably, the activation of FcɛRI-mediated signaling molecules including Syk, PLCγ, and NF-κB was also suppressed by myricetin treatment. Accordingly, myricetin from R. tomentosa fruits could be suggested as a functional food for the amelioration of allergic diseases. PRACTICAL APPLICATIONS: Polyphenol have been shown to exert various biological activities and health beneficial effects. Results from the present study revealed that myricetin from R. tomentosa fruits possesses the inhibitory effect on allergic response in mast cells. Therefore, myricetin from R. tomentosa fruits could be developed as a functional ingredient for the amelioration of allergic diseases.

The Role of Rhodomyrtus tomentosa (Aiton) Hassk. Fruits in Downregulation of Mast Cells-Mediated Allergic Responses

Rhodomyrtus tomentosa, a flowering plant of Myrtaceae family from southern and southeastern Asia, was known to possess a rich source of structurally diverse and various biological activities. In this study, the inhibitory effect of R. tomentosa fruit extract (RFE) on allergic responses in calcium ionophore A23187-activated RBL-2H3 mast cells was investigated. The result showed that RFE was able to inhibit mast cell degranulation via decreasing β-hexosaminidase release and intracellular Ca²⁺ elevation at the concentration of 400 μg/ml. Moreover, the suppressive effects of RFE on the production of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) were evidenced. In addition, RFE effectively scavenged DPPH radical and suppressed the reactive oxygen species generation in a dose-dependent manner. Notably, the pretreatment of RFE caused the downregulation of tyrosine kinase Fyn phospholipid enzyme phospholipase Cγ (PLCγ), extracellular-signal-regulated kinase (ERK), and nuclear factor kappa B (NF-κB) phosphorylation. These results indicated that RFE could be a promising inhibitor of allergic responses and may be developed as bioactive ingredient for prevention or treatment of allergic diseases.

Identification of Chemical Compounds from Karamunting Stem (Rhodomyrtus tomentosa) by Thin Layer Chromatography

Karamunting or Kalimantan Grapes (Rhodomyrtus tomentosa) is a medicinal plant from Central Kalimantan that is easily found in shrubs. Based on hereditary experiences of the people of Central Kalimantan, karamunting can be used for the treatment of various diseases, one of which is diabetes. This study aims to identify the chemical compounds contained in the karamunting stem. The method used is thin layer chromatography with eluent n-hexane : ethyl acetate and methanol : chloroform. Besides, a color reaction was carried out to determine the group of compounds contained in the methanol extract of the karamunting stem. The TLC results show better stain separation in eluent n-hexane : ethyl acetate with the formation of four stains. Positive results are indicated by the content of phenol, saponin, flavonoid and terpenoid compounds. The existence of this group of compounds can be a clue to further research on the truth of the efficacy of karamunting.