Traditional uses, pharmacological activities, and phytochemical constituents of the genus Syzygium: A review

Development of an underutilized part of Syzygium aromaticum based on phytochemical and bioactivity assessment

Syzygium aromaticum is an aromatic plant that has been widely introduced to tropical regions worldwide. S. aromaticum bud (SAB), as a valuable spice, has been used for centuries, owing to its exceptional health benefits and economic value. The fruit of S. aromaticum (SAF) is not a commonly used component and its phytochemical properties and bioactivities have seldom been analyzed. Herein, ultra-performance liquid chromatography-high-resolution mass spectrometry combined with feature-based molecular networking analysis was applied to characterize the phytochemical constituents of these two parts individually. The bioactivities of SAB and SAF were innovatively evaluated, including their hypolipidemic activity on human hepatocellular carcinoma cells, anti-inflammatory activity on RAW264.7 cells, and anti-proliferative activity on vascular smooth muscle cells. Initially, 75 components from SAB and SAF extracts were identified. Subsequently, activity experiments indicated that both SAB and SAF extracts showed significant activities in these cell types. Intriguingly, they showed similar hypolipidemic effects but different anti-inflammatory and anti-proliferative effects. Then, 14 differential markers were screened for further quantitative analysis to explore the material basis for the difference in bioactivity between SAB and SAF. Finally, using correlation analysis, 10 compounds were identified as biomarkers that contributed to the difference in activity between SAB and SAF. These results suggest that SAF is rich in natural metabolites, showing potential as a natural plant component with hypolipidemic, anti-inflammatory, and anti-proliferative effects. This study could contribute to the targeted selection of different parts of S. aromaticum and serve as a foundation for the development and utilization of SAF.

Essential Oils of Neotropical Myrtaceae Species From 2011 Until 2023: An Update

The Myrtaceae family is renowned for its rich diversity of bioactive metabolites with broad applications across various industries. This review comprehensively explores the chemical composition and biological activities of Neotropical species within the Myrtaceae family from 2011 to 2023. A total of 170 papers were analyzed, covering 148 species from 28 genera, with notable emphasis on Eugenia, Eucalyptus, Myrcia, and Psidium. Compounds with relative abundance exceeding 10 % were tabulated to highlight the most significant volatiles for each genus. Our findings were cross-referenced with previous reviews whenever feasible. Antioxidant, antibacterial, and antimicrobial activities emerged as the primary focus, collectively representing 41 % of the studies, predominantly conducted in vitro. Additionally, we discuss less conventional approaches to essential oil studies in Myrtaceae species, underscoring avenues for future exploration. The investigation of essential oils from Myrtaceae holds promise for significant advancements in biotechnology, with potential benefits for the economy, environment, and human health. This review serves as a valuable resource for guiding future research strategies in this field.

Determination of total phenolic and flavonoid contents, antioxidant and antibacterial potential of the bark extracts of Syzygium guineense (Wild.) DC

BACKGROUND

Syzygium guineense (Wild.) DC. is a wild indigenous tree widely used as a traditional medicine for various human ailments in Ethiopia. The purpose of this study was to quantify total phenolic (TPC) and total flavonoid (TFC) contents and determine the antioxidant and antibacterial activities of various solvent extracts of the bark of the plant.

METHODS

The TPC and TFC were determined using Folin-Ciocalteu and aluminum chloride methods, respectively. The 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging, ferric-reducing power, and total antioxidant capacity assays were used to evaluate the antioxidant activities. Antibacterial properties were determined using the disc-diffusion and broth dilution assays.

RESULTS

The ethanol extract of the bark was found to have high TPC (37.80 ± 3.70 mgGAE/g) and TFC (19.22 ± 1.44 mgQE/g). Similarly, the ethanol extract showed stronger DPPH scavenging activity (EC50 = 5.62 μg/mL). The ferric-reducing power and total antioxidant capacity were also strong (163.08±11.67 mgAAE/g and 143.72±2.86 mgBHTE/g of dried extract of 1 mg/mL, respectively). The lowest MIC was observed in acetone extract against S. aureus (1.56 mg/mL) and in ethanol extract against K. pneumoniae (1.56 mg/mL).

CONCLUSION

The ethanol extract of the bark of S. guineense possesses high TPC and TFC. In addition, it showed strong ferric-reducing power and total antioxidant capacity, asserting high antioxidant content. The extracts have shown antibacterial activities against both Gram-positive (S. aureus) and Gram-negative bacterial species. Thus, further in-depth investigations may warrant the isolation of powerful antioxidants and potent antimicrobial agents from the plant.

Essential Oils of The Leaves of Syzygium hemilamprum (F. Muell.) Craven & Biffin.: Chemical Analysis, Antimicrobial, Mosquito Larvicidal, Molecular Docking, and ADMET Studies

The chemical composition of the essential oil and n-hexane extract from Syzygium hemilamprum leaves was first performed. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the essential oil was predominantly composed of monoterpene hydrocarbons (71.5 %) and oxygenated derivatives (20.2 %), with β-pinene (31.5 %), limonene (19.4 %), α-pinene (12.3 %), and α-terpineol (7.4 %) being the principal constituents. The n-hexane extract contained monoterpene hydrocarbons (42.2 %) and non-terpenic compounds (34.0 %), with β-pinene (32.8 %) and n-hexadecane (10.2 %) as the major components. Antimicrobial and mosquito larvicidal assays demonstrated that both samples exhibited antimicrobial activity against Staphylococcus aureus (Gram-positive), Pseudomonas aeruginosa (Gram-negative), and Saccharomyces cerevisiae (yeast), with a minimum inhibitory concentration (MIC) of 128 μg/mL for all tested organisms. Both samples also showed significant mosquito larvicidal activity against Aedes aegypti and Culex quinquefasciatus, with LC50 and LC90 values below 20 μg/mL at 24 and 48 hours post-treatment. Molecular docking studies suggested that limonene and α-terpineol could serve as potent inhibitors of mosquito odorant binding proteins. Additionally, an in silico analysis was performed to evaluate the physicochemical and ADMET (absorption, distribution, metabolism, and toxicity) properties of the major constituents of the essential oil.

The complete chloroplast genome of Syzygium zeylanicum (Myrtaceae, Myrtales) and its phylogenetic analysis

The complete chloroplast genome of Syzygium zeylanicum (L.) DC. 1828 has been sequenced and analyzed for the first time. The S. zeylanicum chloroplast genome is 159,445 bp in length, comprised of a large single-copy region (88,034 bp), a small single-copy region (18,455 bp), and a pair of inverted repeat regions (26,478 bp each). The genome encoded 85 protein-coding genes, 37 tRNA genes, and eight rRNA genes. Phylogenetic analysis indicated that S. zeylanicum is closely related to S. acuminatissimum. This research provides essential genomic data for S. zeylanicum, offering valuable resources for future comparative genomics, phylogenetics, and conservation biology studies.

Exploring Medicinal Plants for Antimicrobial Activity and Synergistic Effects With Doxycycline Against Bacterial Species

Medicinal plants are rich sources of bioactive compounds with diverse pharmacological properties, including antimicrobial activities. This study aimed to assess the antibiofilm potential of methanol and ethanol extracts from nine selected medicinal plants, as well as their synergistic effects with doxycycline against Bacillus strains. Standard procedures were employed to determine the phytochemical composition, total phenolic, and flavonoid contents of the extracts. The antibacterial activity was evaluated using the broth microdilution method, while biofilm formation was assessed via the microtiter plate method. Antibiofilm activity was determined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium-bromide (MTT) assay. Combination studies were conducted using the checkerboard microdilution method. All extracts contained phenols, flavonoids, steroids, triterpenes, and anthraquinones. The methanolic extract of Psidium guajava exhibited the highest total phenolic and flavonoid contents (90.48 ± 0.55 mg GAE/g), while the ethanolic extract of Olax subscorpioidea showed the highest flavonoid content (6.48 ± 0.33 mg QE/g). Ethanol extracts of Eucalyptus globulus and Psidium guajava and methanolic extract of Syzygium jambos demonstrated significant antibacterial activity against Bacillus anthracis 34F2 Sterne strains, with a MIC value of 64 μg/mL. Biofilm formation in Bacillus strains was notably enhanced in the presence of glucose. The methanolic extract of O. subscorpioides exhibited the highest biofilm imbibition (85%), while Picralima nitida methanolic extract showed the most effective biofilm eradication (79%). The combination of Solanum torvum ethanol extract with doxycycline displayed synergistic effects against biofilm formation inhibition and eradication in all tested Bacillus strains. Taken together, Solanum torvum ethanol extract shows promise for developing new combination antibacterial therapies.

Chemical composition, antifungal, antibiofilm, and molecular docking studies of Syzygium dyerianum essential oil

The current study describes the chemical composition, antifungal, antibiofilm, antibacterial and molecular docking studies of Syzygium dyerianum growing in Malaysia. The essential oil was obtained through hydrodistillation and characterized using gas chromatography (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The antifungal and antibacterial activities were developed using the broth microdilution assay, whereas the effect on the microbial biofilms was determined using a semi-quantitative static biofilm assay. A total of 31 components were identified, which represent 99.5 % of the essential oil. The results revealed that the essential oil consisted mainly of β-pinene (15.6 %), α-terpineol (13.3 %), α-pinene (11.1 %), caryophyllene oxide (8.8 %), limonene (8.1 %), borneol (6.0 %) and viridiflorol (5.1 %). The results of the microdilution method showed that essential oil exhibited activity against Candida albicans and Streptococcus mutans with minimal inhibitory concentration values of 125 and 250 μg/mL, respectively. Furthermore, essential oil decreased the biofilm of C. albicans and S. mutans by 20.11 ± 0.27 % and 32.10 ± 4.81 % when treated with 250 μg/mL. The best docking energy was observed with viridiflorol (-29.7 kJ/mol). This study highlights that essential oil can potentially be a natural antifungal, antibacterial, and antibiofilm agent that could be applied in the pharmaceutical and food industries.

Synthesis of Silver Nanoparticles Using Azadirachta indica and Syzygium aromaticum Extract and Its Antibacterial Action Against Enterococcus faecalis: An In Vitro Study

Introduction Nanotechnology is the study of manipulating matter at the atomic scale involving particles smaller than 100 nm. Silver nanoparticles (AgNPs) are gaining popularity across diverse sectors including medical, food, healthcare, consumer goods, and industrial fields due to their distinctive physical and chemical characteristics. The eco-friendly synthesis of AgNPs offers a straightforward, cost-effective, and environmentally benign method devoid of hazardous chemicals. Methodology Eighty milliliters (mL) of silver nitrate mixed with 20 mL of Azadirachta indica and Syzygium aromaticum plant extract underwent two days of magnetic stirring for AgNP synthesis. Characterization was done via ultraviolet-visible (UV-vis)-spectroscopy (300-700 nm), and antimicrobial properties, which were checked with Enterococcus faecalis, were assessed using the agar-well diffusion method. Results The change in color and peak observed in the UV-vis spectrum confirmed the successful synthesis of AgNPs. Both neem and clove extract-mediated synthesis of AgNPs exhibited antibacterial activity against E. faecalis. However, neem extract synthesized AgNPs displayed a larger inhibitory zone diameter and lower minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values compared to those synthesized using clove extract. Conclusion Incorporating neem and clove extracts in AgNP synthesis offers a practical, eco-friendly, and cost-efficient method with notable efficacy. These AgNPs exhibit antibacterial activity against E. faecalis, suggesting their viability as potent antibacterial agents for addressing oral pathogens. Their sustainable synthesis underscores a promising avenue for developing effective antimicrobial solutions in oral healthcare.

Pharmacological and behavioral investigation of putative self-medicative plants in Budongo chimpanzee diets

Wild chimpanzees consume a variety of plants to meet their dietary needs and maintain wellbeing. While some plants have obvious value, others are nutritionally poor and/or contain bioactive toxins which make ingestion costly. In some cases, these nutrient-poor resources are speculated to be medicinal, thought to help individuals combat illness. In this study, we observed two habituated chimpanzee communities living in the Budongo Forest, Uganda, and collected 17 botanical samples associated with putative self-medication behaviors (e.g., bark feeding, dead wood eating, and pith-stripping) or events (e.g., when consumer had elevated parasite load, abnormal urinalysis, or injury). In total, we selected plant parts from 13 species (nine trees and four herbaceous plants). Three extracts of different polarities were produced from each sample using n-hexane, ethyl acetate, and methanol/water (9/1, v/v) and introduced to antibacterial and anti-inflammatory in vitro models. Extracts were evaluated for growth inhibition against a panel of multidrug-resistant clinical isolates of bacteria, including ESKAPE strains and cyclooxygenase-2 (COX-2) inhibition activity. Pharmacological results suggest that Budongo chimpanzees consume several species with potent medicinal properties. In the antibacterial library screen, 45 out of 53 extracts (88%) exhibited ≥40% inhibition at a concentration of 256 μg/mL. Of these active extracts, 41 (91%) showed activity at ≤256μg/mL in subsequent dose-response antibacterial experiments. The strongest antibacterial activity was achieved by the n-hexane extract of Alstonia boonei dead wood against Staphylococcus aureus (IC50: 16 μg/mL; MIC: 32 μg/mL) and Enterococcus faecium (IC50: 16 μg/mL; MIC: >256 μg/mL) and by the methanol-water extract of Khaya anthotheca bark and resin against E. faecium (IC50: 16 μg/mL; MIC: 32 μg/mL) and pathogenic Escherichia coli (IC50: 16 μg/mL; MIC: 256 μg/mL). We observed ingestion of both these species by highly parasitized individuals. K. anthotheca bark and resin were also targeted by individuals with indicators of infection and injuries. All plant species negatively affected growth of E. coli. In the anti-inflammatory COX-2 inhibition library screen, 17 out of 51 tested extracts (33%) showed ≥50% COX-2 inhibition at a concentration of 5 μg/mL. Several extracts also exhibited anti-inflammatory effects in COX-2 dose-response experiments. The K. anthotheca bark and resin methanol-water extract showed the most potent effects (IC50: 0.55 μg/mL), followed by the fern Christella parasitica methanol-water extract (IC50: 0.81 μg/mL). This fern species was consumed by an injured individual, a feeding behavior documented only once before in this population. These results, integrated with associated observations from eight months of behavioral data, provide further evidence for the presence of self-medicative resources in wild chimpanzee diets. This study addresses the challenge of distinguishing preventative medicinal food consumption from therapeutic self-medication by integrating pharmacological, observational, and health monitoring data-an essential interdisciplinary approach for advancing the field of zoopharmacognosy.

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.

Biological and Medicinal Properties of Natural Chromones and Chromanones

Emerging threats to human health require a concerted effort to search for new treatment therapies. One of the biggest challenges is finding medicines with few or no side effects. Natural products have historically contributed to major advances in the field of pharmacotherapy, as they offer special characteristics compared to conventional synthetic molecules. Interest in natural products is being revitalized, in a continuous search for lead structures that can be used as models for the development of new medicines by the pharmaceutical industry. Chromone and chromanones are recognized as privileged structures and useful templates for the design of diversified therapeutic molecules with potential pharmacological interest. Chromones and chromanones are widely distributed in plants and fungi, and significant biological activities, namely antioxidant, anti-inflammatory, antimicrobial, antiviral, etc., have been reported for these compounds, suggesting their potential as lead drug candidates. This review aims to update the literature published over the last 6 years (2018-2023) regarding the natural occurrence and biological activity of chromones and chromanones, highlighting the recent findings and the perspectives that they hold for future research and applications namely in health, cosmetic, and food industries.

Biofilm inhibition/eradication: exploring strategies and confronting challenges in combatting biofilm

Biofilms are complex communities of microorganisms enclosed in a self-produced extracellular matrix, posing a significant threat to different sectors, including healthcare and industry. This review provides an overview of the challenges faced due to biofilm formation and different novel strategies that can combat biofilm formation. Bacteria inside the biofilm exhibit increased resistance against different antimicrobial agents, including conventional antibiotics, which can lead to severe problems in livestock and animals, including humans. In addition, biofilm formation also imposes heavy economic pressure on industries. Hence it becomes necessary to explore newer alternatives to eradicate biofilms effectively without applying selection pressure on the bacteria. Excessive usage of antibiotics may also lead to an increase in the number of resistant strains as bacteria employ an advanced antimicrobial resistance mechanism. This review provides insight into multifaceted technologies like quorum sensing inhibition, enzymes, antimicrobial peptides, bacteriophage, phytocompounds, and nanotechnology to neutralize biofilms without developing antimicrobial resistance (AMR). Furthermore, it will pave the way for developing newer therapeutic agents to deal with biofilms more efficiently.

Syzygium cumini ameliorates high fat diet induced glucose intolerance, insulin resistance, weight gain, hepatic injury and nephrotoxicity through modulation of PTP1B and PPARγ signaling

Metabolic disorders are majorly associated with insulin resistance and an impaired glucose tolerance. Since, many of the currently available drugs exhibit adverse effects and are resistant to therapies, natural products are a promising alternate in the alleviation of complex metabolic disorders. In the current study, Syzygium cumini methanolic extract (SCE) was investigated for its anti-diabetic and anti-adipogenic potential using C57BL/6 mice fed on high fat diet (HFD). The HFD fed obese mice were treated with 200 mg/kg SCE and compared with positive controls Metformin, Pioglitazone and Sodium Orthovanadate. The biometabolites in SCE were characterized using Fourier transform infrared and gas chromatography and mass spectroscopy. A reduction in blood glucose levels with improved insulin sensitivity and glucose tolerance was observed in SCE-treated HFD obese mice. Histopathological and biochemical investigations showed a reduction in hepatic injury and nephrotoxicity in SCE-administered HFD mice. Results showed inhibition of PTP1B and an upregulation of IRS1 and PKB-mediated signaling in skeletal muscle. A significant decrease in lipid markers such as TC, TG, LDL-c and VLDL-c levels were observed with increased HDL-c in SCE-treated HFD mice. A significant decrease in weight and adiposity was observed in SCE-administered HFD mice in comparison to controls. This decrease could be due to the partial agonism of PPARγ and an increased expression of adiponectin, an insulin sensitizer. Hence, the dual-modulatory effect of SCE, partly due to the presence of 26% Pyrogallol, could be useful in the management of diabetes and its associated maladies.

Undescribed Triterpenes from the Leaves of Syzygium myrsinifolium with Their α-Glucosidase and α-Amylase Inhibition Activity

Two undescribed triterpenes, syzyfolium A (1) and syzyfolium B (2), together with twelve known compounds, terminolic acid (3), actinidic acid (4), piscidinol A (5), threo-dihydroxydehydrodiconiferyl alcohol (6), lariciresinol-4-O-β-D-glucoside (7), icariol A2 (8), 14β,15β-dihydroxyklaineanone (9), garcimangosone D (10), (+)-catechin (11), myricetin-3-O-α-L-rhamnopyranoside (12), quercitrin (13), and 3, 4, 5-trimethoxyphenyl-(6'-O-galloyl)-O-β-D-glucopyranoside (14) were isolated from the leaves of Syzygium myrsinifolium. Their chemical structures were determined by IR, HR-ESI-MS, 1D and 2D NMR spectra. Compounds 3 and 4 inhibited significantly α-glucosidase with IC50 values of 23.99 and 36.84, respectively, and compounds 1 and 2 inhibited significantly α-amylase with IC50 values of 35.48 and 43.65 μM, respectively.

Apoptosis-inducing anti-proliferative and quantitative phytochemical profiling with in silico study of antioxidant-rich Leea aequata L. leaves

Natural products have been important parts of traditional medicine since ancient times, with various promising health effects. Leea aequata (L. aequata), a natural product, has been widely used for treating several diseases due to its promising pharmacological activities. Therefore, the present study aimed to explore the phytochemical profiling and molecular docking of the antioxidant-rich part of L. aequata leaves and its antiproliferative activity. L. aequata leaves were extracted with methanol, followed by fractionation with the respective solvents to obtain the petroleum ether, chloroform, ethyl acetate, and aqueous fractions. The antioxidant activity was evaluated by spectrophotometric methods. The cytotoxic and antiproliferative activities were detected using MTT colorimetric and confocal microscopy methods, respectively. Phytochemical compositions were analyzed using gas chromatography‒mass spectrometry analysis. Computer aided (molecular docking SwissADME, AdmetSAR and pass prediction) analyses were undertaken to sort out the best-fit phytochemicals present in the plant responsible for antioxidant and anticancer effects. Among the fractions, the ethyl acetate fraction was the most abundant polyphenol-rich fraction and showed the highest antioxidant, reducing power, and free radical scavenging activities. Compared to untreated MCF-7 cells, ethyl acetate fraction-treated MCF-7 cells showed an increase in apoptotic characteristics, such as membrane blebbing, chromatin condensation, and nuclear fragmentation, causing apoptosis and decreased proliferation of HeLa and MCF-7 cells. Furthermore, gas chromatography mass spectrometry data revealed that the ethyl acetate fraction contained 16 compounds, including methyl esters of long-chain fatty acids, which are the major chemical constituents. Moreover, hexadecanoic acid, methyl ester; 9-octadecenoic acid (Z)-, methyl ester; 9,12-octadecadienoic acid, methyl ester (Z, Z) and phenol, 2,4-bis(1,1-dimethylethyl) are known to have antioxidant and cytotoxic activity, as confirmed by computer-aided models. A strong correlation was observed between the antioxidant and polyphenolic contents and the anticancer activity. In conclusion, we explored the possibility that L. aequata could be a promising source of antioxidants and anticancer agents with a high phytochemical profile.

Phytochemical profile and antimicrobial activity of essential oils from two Syzygium species against selected oral pathogens

BACKGROUND

The genus Syzygium (Myrtaceae) comprises several essential oil-rich species that are utilized traditionally for treating tooth infections and toothache. The current study aimed to extract essential oils (EOs) from the leaves of Syzygium samarangense and Syzygium malaccense cultivated in Egypt for the first time and screen their antimicrobial potential against oral-related pathogens.

METHODS

The intended EOs were extracted using hydrodistillation (HD) by boiling fresh leaves with distilled water; supercritical fluid (SF) by extracting the dried leaves using supercritical CO2 at 40 °C and 150 bar; and the headspace (HS) in which the fresh leaves were heated in a glass vial and the vaporized aroma were analyzed. The volatile constituents were analyzed using GC/MS and identified by comparing the experimental Kovats' retention indices with the literature. The antimicrobial activity was assessed against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Candida albicans using agar diffusion, microwell dilution, and biofilm formation assays. Statistical significance (p < 0.05) was determined by applying one-way ANOVA and Duncan's post hoc test.

RESULTS

The yield of the extracted EOs differs between the applied methods, and the SF approach harvested the maximum (0.52-0.46%). The GC-MS analysis of SF EOs revealed a discrepancy between the two species. Since S. malaccense showed an abundance of hydrocarbons represented mainly by squalene (60.60%), S. samarangense was deemed to have oxygenated sesquiterpenes exemplified in globulol (52.09%). On the other side, the HD and HS EOs were sequentially comparable, while differed in the percentage of their majors. γ-terpinene (33.06%) pioneered the HS-derived aroma of S. malaccense, while S. samarangense was abundant with α-pinene (30.18%). Concurrently, the HD EOs of S. malaccense and S. samarangense were commonly denoted by caryophyllene oxide (8.19%-18.48%), p-cymene (16.02%- 19.50%), and γ-terpinene (12.20%-17.84). Ultimately, both species EOs exhibited broad-spectrum antimicrobial potential, although the HD EO was more potent than the SF EO. The HD EOs of both species potently inhibited the growth of E. coli (MIC 3.75 µL/mL) and suppressed C. albicans biofilm formation by 83.43 and 87.27%, respectively. The SF-EOs efficiently suppressed the biofilm formation of Gram-positive bacteria by 76.45%-82.95%.

CONCLUSION

EOs extracted from both species by different methods possessed a unique blend of volatile components with broad-spectrum antimicrobial activity. They were promoted as bioactive hits for controlling oral infections, however further investigations concerning their safety in clinical settings are needed.

Essential Oils of Five Syzygium Species Growing Wild in Vietnam: Chemical Compositions and Antimicrobial and Mosquito Larvicidal Potentials

The essential oils of five Vietnamese Syzygium species (Syzygium levinei, S. acuminatissimum, S. vestitum, S. cumini, and S. buxifolium) were first hydro-distilled and analyzed using GC-FID/MS (gas chromatography-flame ionization detection/mass spectrometry). Monoterpene hydrocarbons, sesquiterpene hydrocarbons, and oxygenated sesquiterpenoids were the main chemical classes in these oils. All these essential oils showed good-excellent antimicrobial activities against Gram-positive bacteria Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus, and the yeast Candida albicans. S. levinei leaf essential oil, rich in bicyclogermacrene (25.3%), (E)-β-elemene (12.2%), (E)-caryophyllene (8.2%), and β-selinene (7.4%), as well as S. acuminatissimum fruit essential oil containing (E)-caryophyllene (14.2%), α-pinene (12.1%), caryophyllene oxide (10.9%), β-selinene (10.8%), α-selinene (8.0%), and α-humulene (5.7%), established the same MIC value of 8 µg/mL against E. faecalis and B. cereus, which were much better than the positive control streptomycin (MIC 128-256 µg/mL). The studied essential oils showed the potential to defend against mosquitoes since they caused the 24 and 48 h LC50 values of less than 50 µg/mL against the growth of Culex quinquefasciatus and Aedes aegypti larvae. Especially, S. buxifolium leaf essential oil strongly inhibited Ae. aegypti larvae with 24 and 48 h LC50 values of 6.73 and 6.73 µg/mL, respectively, and 24 and 48 h LC90 values of 13.37 and 10.83 µg/mL, respectively. These findings imply that Vietnamese Syzygium essential oils might have potential for use as supplemental antibacterial agents or as "green" alternatives for the control of mosquitoes.

Chromosome-scale assemblies of S. malaccense, S. aqueum, S. jambos, and S. syzygioides provide insights into the evolution of Syzygium genomes

Syzygium is a large and diverse tree genus in the Myrtaceae family. Genome assemblies for clove (Syzygium aromaticum, 370 Mb) and sea apple (Syzygium grande, 405 Mb) provided the first insights into the genomic features and evolution of the Syzygium genus. Here, we present additional de novo chromosome-scale genome assemblies for Syzygium malaccense, Syzygium aqueum, Syzygium jambos, and Syzygium syzygioides. Genome profiling analyses show that S. malaccense, like S. aromaticum and S. grande, is diploid (2n = 2x = 22), while the S. aqueum, S. jambos, and S. syzygioides specimens are autotetraploid (2n = 4x = 44). The genome assemblies of S. malaccense (430 Mb), S. aqueum (392 Mb), S. jambos (426 Mb), and S. syzygioides (431 Mb) are highly complete (BUSCO scores of 98%). Comparative genomics analyses showed conserved organization of the 11 chromosomes with S. aromaticum and S. grande, and revealed species-specific evolutionary dynamics of the long terminal repeat retrotransposon elements belonging to the Gypsy and Copia lineages. This set of Syzygium genomes is a valuable resource for future structural and functional comparative genomic studies on Myrtaceae species.

Synergistic Antigenotoxic and Antioxidant Action of Gum Arabic and Eugenol in Rat Liver Following Induction of Colorectal Carcinogenesis

OBJECTIVE

Much research has been conducted to identify natural antioxidant and antimutagenic compounds capable of preventing, reverting or treating conditions caused by oxidative stress and genotoxicity. In this study we evaluated the effects of 10% gum arabic (GA) and eugenol (EUG) on hepatic oxidative stress and genotoxicity induced by dimethylhydrazine (DMH) in rats.

METHODS

The prevention arm of the study included 4 control groups and 4 experimental groups. Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the same period and for an additional 9 weeks, the animals received either water, 10% GA , EUG or 10% GA + EUG  by gavage. The treatment arm of the study included 4 control groups and 4 experimental groups. Once a week for 20 weeks, the controls received saline s.c. while the experimental groups received DMH at 20 mg/kg s.c. During the subsequent 9 weeks, the animals received either water, 10% GA, EUG or 10% GA + EUG  by gavage. Finally, the livers were harvested for histopathological study with HE, measurement of genotoxicity and oxidative stress.

RESULT

Genotoxicity and oxidative stress were found to be significantly lower in Group XII (animals treated concomitantly with GA and EUG). This is the first study to observe the synergistic action of GA and EUG administered concomitantly in this scenario.

CONCLUSION

Indicating a synergistic antigenotoxic and antioxidant effect on liver cells in rats with DMH-induced colorectal carcinogenesis.

Application of Iron Nanoparticles Synthesized from a Bioflocculant Produced by Yeast Strain Pichia kudriavzevii Obtained from Kombucha Tea SCOBY in the Treatment of Wastewater

Studying the production of Iron (Fe) nanoparticles using natural substances is an intriguing area of research in nanotechnology, as these nanoparticles possess biocompatibility and natural stability, which make them useful for a variety of industrial applications. The study utilized Fe nanoparticles that were synthesized using a bioflocculant and applied to eliminate different kinds of pollutants and dyes found in wastewater and solutions. The study involved the generation of Fe nanoparticles through a bioflocculant obtained from Pichia kudriavzevii, which were evaluated for their flocculation and antimicrobial capabilities. The impact of the Fe nanoparticles on human embryonic kidney (HEK 293) cell lines was studied to assess their potential cytotoxicity effects. An array of spectroscopic and microscopic methods was employed to characterize the biosynthesized Fe nanoparticles, including SEM-EDX, FT-IR, TEM, XRD, UV-vis, and TGA. A highly efficient flocculating activity of 85% was achieved with 0.6 mg/mL dosage of Fe nanoparticles. The biosynthesized Fe nanoparticles demonstrated a noteworthy concentration-dependent cytotoxicity effect on HEK 293 cell lines with the highest concentration used resulting in 34% cell survival. The Fe nanoparticles exhibited strong antimicrobial properties against a variety of evaluated Gram-positive and Gram-negative microorganisms. The efficiency of removing dyes by the nanoparticles was found to be higher than 65% for the tested dyes, with the highest being 93% for safranine. The Fe nanoparticles demonstrated remarkable efficiency in removing various pollutants from wastewater. In comparison to traditional flocculants and the bioflocculant, biosynthesized Fe nanoparticles possess significant potential for eliminating both biological oxygen demand (BOD) and chemical oxygen demand (COD) from wastewater samples treated. Hence, the Fe nanoparticles synthesized in this way have the potential to substitute chemical flocculants in the treatment of wastewater.

Ethnomedicinal Knowledge of Plants Used in Nonconventional Medicine in the Management of Diabetes Mellitus in Kinshasa (Democratic Republic of the Congo)

Background

People with diabetes, herbalists, and traditional medicine practitioners (TMPs) from Kinshasa use plants to treat diabetes, but no study has inventoried the plants used by these populations. The present study was conducted to identify the plants used in Kinshasa to treat diabetes mellitus.

Methods

The survey conducted in the form of a semistructured interview between March 2005 and August 2006 made it possible to collect ethnobotanical information from people with diabetes (n = 126), herbalists (n = 80), and TMPs (n = 120).

Results

The 326 subjects consulted (sex ratio M/F = 0.6, age 51 ± 7 years, and experience: 17 ± 5 years) provided information on 71 plants, most of which are trees (35%), belonging to 38 families dominated by Fabaceae (19.7%) and indicated in 51 other cases of consultation dominated by malaria (12%). From these 71 plants derived, 86 antidiabetic recipes were administered orally, where the leaf is the most used part (>50%) and the decoction (>46%) is the most common mode of preparation. This study reports for the first time the antidiabetic use of 11 species, among which Tephrosia vogeliiX (0.08), Chromolaena corymbosaX (0.06), and Baphia capparidifoliaX (0.06) present the highest consensus indexes (CI) and Marsdenia latifoliaW (UVp = 0.08) and Rauvolfia manniiX (UVp = 0.06) present the highest UVs.

Conclusion

The results show that Kinshasa people treat diabetes using several plants. Some are specific to the ecological environment; others are used in other regions. Pharmacological studies are underway to assess the therapeutic efficacy of these plants.

Undescribed Phenolic Glycosides from Syzygium attopeuense and Their Inhibition of Nitric Oxide Production

Four undescribed phenolic glycosides including three stilbene derivatives (1 and 3) and sodium salt of 3 (2), and a chalcone glycoside (4), together with thirteen known compounds (5-17) were isolated from the leaves of Syzygium attopeuense (Gagnep.) Merr. & L.M.Perry. Their chemical structures were elucidated to be (Z)-gaylussacin (1), 6''-O-galloylgaylussacin sodium salt (2), 6''-O-galloylgaylussacin (3), 4'-O-[β-D-glucopyranosyl-(1→6)-glucopyranosyl]oxy-2'-hydroxy-6'-methoxydihydrochalcone (4), gaylussacin (5), pinosilvin 3-O-β-D-glucopyranoside (6), myricetin-3-O-(2''-O-galloyl)-α-L-rhamnopyranoside (7), myricetin-3-O-(3''-O-galloyl)-α-L-rhamnopyranoside (8), myricetin-3-O-α-L-rhamnopyranoside (9), quercitrin (10), myricetin-3-O-β-D-glucopyranoside (11), myricetin-3-O-β-D-galactopyranoside (12), quercetin 3-O-α-L-arabinopyranoside (13), myricetin-3-O-2''-O-galloyl)-α-L-arabinopyranoside (14), (+)-gallocatechin (15), (-)-epigallocatechin (16), and 3,3',4'-trimethoxyellagic acid 4-O-β-D-glucopyranoside (17) by the analysis of HR-ESI-MS, 1D and 2D NMR spectra in comparison with the previously reported data. Compounds 1-3, 5, and 6 significant inhibition of NO production in LPS-activated RAW264.7 cells, with IC50 values ranging from 18.37±1.38 to 35.12±2.53 μM, compared to a positive control (dexamethasone) with an IC50 value of 15.37±1.42 μM.

The α-glucosidase inhibitory activity of avicularin and 4-O-methyl gallic acid isolated from Syzygium myrtifolium leaves

Diabetes Mellitus is the main cause of death on a global scale. In 2019, there were 463 million people with diabetes, and WHO predicts that by 2030, there will be 578 million. As an antidiabetic agent, α-glucosidase inhibitors are one of the methods employed to reduce the prevalence of diabetes. Diabetes is traditionally treated with Syzygium as a primary material, medicine, fruit, ornamental plant, and source of carpentry. This investigation aimed to examine the inhibitory effect of seven species of Syzygium against α-glucosidase enzyme using an in vitro assay and isolate active substances and ascertain their concentrations in each sample. As a solvent, ethanol was used in maceration to extract the substance. Afterward, the extract underwent a series of fractionation techniques, including liquid-liquid extraction, vacuum liquid chromatography, column chromatography, and preparative Thin Layer Chromatography (TLC) for purification and isolation. The compound's structures were elucidated using TLC, UV-Visible spectrophotometry, and nuclear magnetic resonance (NMR) spectroscopy. Based on concentrations of 100 and 200 µg/mL, Syzygium myrtifolium exhibited the most significant inhibitory effect, followed by other species of Syzygium. The proportion of ethyl acetate had the strongest activity (IC₅₀ 0.40 ± 0.02 µg/mL) contrasted to positive control acarbose (IC₅₀ 55.39 ± 0.67 g/mL) and quercitrin (IC₅₀ 6.47 ± 0.40 µg/mL). Avicularin and 4-O-methyl gallic acid were discovered in the ethyl acetate fraction of Syzygium myrtifolium with IC₅₀ values of 17.05 ± 0.75 µg/mL and 25.19 ± 0.21 µg/mL, respectively. As α-glucosidase inhibitory, the results of this study indicate Syzygium myrtifolium can be used as a dietary supplement to manage hyperglycemia.

Improvement of phytochemical and quality characteristics of Dracocephalum kotschyi by drying methods

This experiment was conducted to evaluate the effects of different drying methods on drying parameters and qualitative characteristics of Dracocephalum kotschyi in a completely randomized design with three replications. Treatments included shade drying as control, sun drying, cabinet drying (CD at 50 and 60°C), refractance window drying (RWD), infrared drying (IRD) at 200 and 300 W, and combination of RWD+ IRD at 200 and 300 W. According to the results, IRD, RWD, and RWD+ IRD effectively maintained valuable secondary metabolites compared to the conventional drying methods. The maximum total phenol content (2.7 and 2.66 mg GAE/g dry weight), total flavonoid content (2.26 and 2.33 mg QE/g dry weight), antioxidant activity (79% and 78.33%), and essential oil content (0.65% and 0.76%) were obtained from plants dried by RWD and IRD. Samples dried by RWD, IRD, and RWD+ IRD had high color quality, acceptable green color, and less browning. Also, RWD and IRD methods effectively reduced microbial contamination of dried plants compared to the control and other methods. The minimum aerobic mesophiles, mold, yeast, and coliforms were observed at 3.11, 0, and 1.47 log CFU/g in IRD 300 W and 3.17, 1, and 1.30 log CFU/g in RWD. D. kotschyi dried at CD 50°C had the maximum microbial contamination. Generally, according to the obtained results, RWD and IRD methods are suggested for drying of D. kotschyi and similar herbs due to shortening the drying time, preserving and improving the quality properties of dried plants.

Potential of Syzygnium polyanthum as Natural Food Preservative: A Review

Food preservation is one of the strategies taken to maintain the level of public health. Oxidation activity and microbial contamination are the primary causes of food spoilage. For health reasons, people prefer natural preservatives over synthetic ones. Syzygnium polyanthum is widely spread throughout Asia and is utilized as a spice by the community. S. polyanthum has been found to be rich in phenols, hydroquinones, tannins, and flavonoids, which are potential antioxidants and antimicrobial agents. Consequently, S. polyanthum presents a tremendous opportunity as a natural preservative. This paper reviews recent articles about S. polyanthum dating back to the year 2000. This review summarizes the findings of natural compounds presented in S. polyanthum and their functional properties as antioxidants, antimicrobial agents, and natural preservatives in various types of food.

New Isopropyl Chromone and Flavanone Glucoside Compounds from the Leaves of Syzygium cerasiforme (Blume) Merr. & L.M.Perry and Their Inhibition of Nitric Oxide Production

A new isopropyl chromone (1) and a new flavanone glucoside (2) together with eleven known compounds (3-13) were isolated from the leaves of Syzygium cerasiforme (Blume) Merr. & L.M.Perry. Their structures were elucidated as 5,7-dihydroxy-2-isopropyl-6,8-dimethyl-4H-chromen-4-one (1), 5,7-dihydroxyflavanone 7-O-β-D-(6''-O-galloylglucopyranoside) (2), strobopinin (3), demethoxymatteucinol (4), pinocembrin-7-O-β-D-glucopyranoside (5), (2S)-hydroxynaringenin-7-O-β-D-glucopyranoside (6), afzelin (7), quercetin (8), kaplanin (9), endoperoxide G3 (10), grasshopper (11), vomifoliol (12), litseagermacrane (13) by the analysis of HR-ESI-MS, NMR, and CD spectral data. Compounds 1, 2, 5, 6 and 10 inhibited NO production on LPS-activated RAW264.7 cells with IC50 values of 12.28±1.15, 8.52±1.62, 7.68±0.87, 9.67±0.57, and 6.69±0.34 μM, respectively, while the IC50 values of the other compounds ranging from 33.38±0.78 to 86.51±2.98 μM, compared to that of the positive control, NG -monomethyl-L-arginine acetate (L-NMMA) with an IC50 value of 32.50±1.00 μM.

Chemical composition, antimicrobial and larvicidal activities of essential oils of two Syzygium species from Vietnam

The present study is the first to investigate the chemical composition, antimicrobial and larvicidal activities of the essential oils from the leaves of Syzygium attopeuense (Gagnep.) Merr. & L.M.Perry and Syzygium tonkinense (Gagnep.) Merr. & L.M.Perry collected in Vietnam. The essential oils were extracted by hydrodistillation and analyzed by GC and GC-MS. The study indicated the presence of a high percentage of sesquiterpenes in both investigated essential oils. The major components of S. attopeuense essential oil were bicyclogermacrene (24.26%), (E)-caryophyllene (11.72%), and (E)-β-ocimene (6.75%), whereas S. tonkinense essential oil was dominated by (E)-caryophyllene (80.80%). The antimicrobial activity of essential oils was evaluated by broth microdilution assay to determine the minimum inhibitory concentration (MIC) and median inhibitory concentration (IC50). Both essential oils exhibited remarkable inhibitory activity against all tested Gram-positive bacteria and yeast than Gram-negative bacteria. Among them, essential oils of S. attopeuense and S. tonkinense possessed the strongest activity against Enterococcus faecalis (MIC = 4.00 μg/mL; IC50 = 1.69 μg/mL) and Candida albicans (MIC = 16.00 μg/mL; IC50 = 8.67 μg/mL), respectively. Furthermore, the larvicidal activity of essential oils was tested using fourth-instar larvae of Aedes aegypti. Results from the larvicidal test revealed that both essential oils had an excellent inhibitory effect against A. aegypti larvae with LC50 values from 25.55 to 30.18 μg/mL and LC90 values from 33.00 to 39.01 μg/mL. Our findings demonstrate that the essential oil extracted from S. attopeuense and S. tonkinense are potential sources of natural antimicrobials and can act as inexpensive mosquito larvicidal agents.

Roles of Syzygium in Anti-Cholinesterase, Anti-Diabetic, Anti-Inflammatory, and Antioxidant: From Alzheimer's Perspective

Alzheimer's disease (AD) causes progressive memory loss and cognitive dysfunction. It is triggered by multifaceted burdens such as cholinergic toxicity, insulin resistance, neuroinflammation, and oxidative stress. Syzygium plants are ethnomedicinally used in treating inflammation, diabetes, as well as memory impairment. They are rich in antioxidant phenolic compounds, which can be multi-target neuroprotective agents against AD. This review attempts to review the pharmacological importance of the Syzygium genus in neuroprotection, focusing on anti-cholinesterase, anti-diabetic, anti-inflammatory, and antioxidant properties. Articles published in bibliographic databases within recent years relevant to neuroprotection were reviewed. About 10 species were examined for their anti-cholinesterase capacity. Most studies were conducted in the form of extracts rather than compounds. Syzygium aromaticum (particularly its essential oil and eugenol component) represents the most studied species owing to its economic significance in food and therapy. The molecular mechanisms of Syzygium species in neuroprotection include the inhibition of AChE to correct cholinergic transmission, suppression of pro-inflammatory mediators, oxidative stress markers, RIS production, enhancement of antioxidant enzymes, the restoration of brain ions homeostasis, the inhibition of microglial invasion, the modulation of ß-cell insulin release, the enhancement of lipid accumulation, glucose uptake, and adiponectin secretion via the activation of the insulin signaling pathway. Additional efforts are warranted to explore less studied species, including the Australian and Western Syzygium species. The effectiveness of the Syzygium genus in neuroprotective responses is markedly established, but further compound isolation, in silico, and clinical studies are demanded.