Naturally Derived Malabaricone B as a Promising Bactericidal Candidate Targeting Multidrug-Resistant Staphylococcus aureus also Possess Synergistic Interactions with Clinical Antibiotics.

The emergence of multidrug-resistant (MDR) superbugs underlines the urgent need for innovative treatment options to tackle resistant bacterial infections. The clinical efficacy of natural products directed our efforts towards developing new antibacterial leads from naturally abundant known chemical structures. The present study aimed to explore an unusual class of phenylacylphenols (malabaricones) from Myristicamalabarica as antibacterial agents. In vitro antibacterial activity was determined via broth microdilution, cell viability, time-kill kinetics, biofilm eradication, intracellular killing, and checkerboard assays. The efficacy was evaluated in vivo in murine neutropenic thigh and skin infection models. Confocal and SEM analyses were used for mechanistic studies. Among the tested isolates, malabaricone B (NS-7) demonstrated the best activity against S. aureus with a favorable selectivity index and concentration-dependent, rapid bactericidal killing kinetics. It displayed equal efficacy against MDR clinical isolates of S. aureus and Enterococci, efficiently clearing S. aureus in intracellular and biofilm tests, with no detectable resistance. In addition, NS-7 synergized with daptomycin and gentamicin. In vivo, NS-7 exhibited significant efficacy against S. aureus infection. Mechanistically, NS-7 damaged S. aureus membrane integrity, resulting in the release of extracellular ATP. The results indicated that NS-7 can act as a naturally derived bactericidal drug lead for anti-staphylococcal therapy.

Mechanical superiority of Pseudoxytenanthera bamboo for sustainable engineering solutions.

The advancement in natural fibre composites has replaced synthetic fibres in various commercial sectors. Bamboo species possess high mechanical properties due to their lignocellulosic fibre content, which makes them suitable for engineering applications and potential alternatives to solid wood. However, despite Bamboo being composed of 130 genera and 1700 different species, out of which many still remains underexplored. In this study, we investigated the, Lignocellulosic profiling, fibre strength, and mechanical characterization of two species of Pseudoxytenanthera Bamboo: Pseudoxytenanthera ritchiei, Pseudopxytenanthera stocksii, and the results obtained were compared with Bambusa balcooa, one of the priority species of bamboo identified by The International Plant Genetic Resources Institute (IPGRI). BET (Brunauer-Emmett-Teller) was used to quantify the samples' density, while SEM-EDX and FTIR spectroscopy were used for elemental analysis. The samples were then subjected to tensile test in addition, thermogravimetric analysis and water absorption test were carried out for the three species. The results showed that Pseudoxytenanthera species possessed superior chemical and mechanical characteristics compared to the priority species of bamboo used for composites. Out of the two Pseudoxytenanthera species studied, Pseudoxytenanthera stocksii exhibited the highest values of cellulose, hemicellulose, lignin, pectin, ash, carbon, and silicon, indicating its chemical superiority. Moreover, Pseudoxytenanthera stocksii also showed higher mechanical values for tensile strength, making it suitable for a variety of engineering applications. The TGA values also indicated that Pseudoxytenanthera stocksii is stable at high temperatures when compared with other natural fibres.

The Anti-Biofilm Potential of Linalool, a Major Compound from Hedychium larsenii, against Streptococcus pyogenes and Its Toxicity Assessment in Danio rerio.

The anti-biofilm and anti-virulence potential of the essential oil (E.O.) extracted from Hedychium larsenii M. Dan & Sathish was determined against Streptococcus pyogenes. A crystal violet assay was employed to quantify the biofilm. Linalool, a monoterpene alcohol from the E.O., showed concentration-dependent biofilm inhibition, with a maximum of 91% at a concentration of 0.004% (v/v). The AlamarBlueTM assay also confirmed Linalool's non-bactericidal anti-biofilm efficacy (0.004%). Linalool treatment impeded micro-colony formation, mature biofilm architecture, surface coverage, and biofilm thickness and impaired cell surface hydrophobicity and EPS production. Cysteine protease synthesis was quantified using the Azocasein assay, and Linalool treatment augmented its production. This suggests that Linalool destabilizes the biofilm matrix. It altered the expression of core regulons covRS, mga, srv, and ropB, and genes associated with virulence and biofilm formation, such as speB, dltA, slo, hasA, and ciaH, as revealed by qPCR analysis. Cytotoxicity analysis using human kidney cells (HEK) and the histopathological analysis in Danio rerio proved Linalool to be a druggable molecule against the biofilms formed by S. pyogenes. This is the first report on Linalool's anti-biofilm and anti-virulence potential against S. pyogenes.

Antiproliferative labdane diterpenes from the rhizomes of Hedychium flavescens Carey ex Roscoe.

Antiproliferative activity was confirmed in the various extracts of rhizomes of Hedychium flavescens (Zingiberaceae). The phytochemical investigation of the rhizomes of Hedychium flavescens led to the isolation of four labdane diterpenes. Their structures were established as coronarin E (1), C-14 epimers of isocoronarin D (2), C-15 epimers of coronarin D methyl ether (3) and isocoronarin D (4). The structure of the compounds was identified based on spectroscopic analysis and on comparison with literature reports. All these compounds were assessed for their in vitro cytotoxicity against human lung adenocarcinoma (A549) cell line and showed significant cytotoxicity as reflected in IC50 value, that is, 0.52, 0.59, 0.68 and 1.22 µM compared with the control doxorubicin (IC50 0.92 µM). Moreover, all the compounds were nontoxic towards the normal lung fibroblast (WI-38) cells. The chemo-profiling and cytotoxicity study of Hedychium flavescens is reported for the first time.

Zerumbone, a Cyclic Sesquiterpene from Zingiber zerumbet Induces Apoptosis, Cell Cycle Arrest, and Antimigratory Effects in SW480 Colorectal Cancer Cells.

Zerumbone isolated from the rhizomes of Zingiber zerumbet was investigated for the mechanisms by which it exhibits antiproliferative activity in colorectal cancer cells (SW480). The results indicated that the zerumbone suppressed cell growth and enhanced cell apoptosis. Exposure to zerumbone induced generation of reactive oxygen species, reduced the cellular antioxidant status, decreased mitochondrial membrane potential, and activated caspase 3, caspase 8, and caspase 9 (p < 0.001). It was also found that there was a decrease in the expression of Bcl 2 and elevation of Bax (p < 0.001) on exposure to zerumbone. Furthermore, treatment with 50, 75, and 100 µM zerumbone resulted in cell cycle arrest at the G2/M phase with a value of 17.2 ± 0.1, 19.63 ± 0.25, and 26.66 ± 0.25, respectively, and also distorted the microfilament network and effectively inhibited cellular migration.

Chemical profile, antiproliferative and antioxidant activities of rhizome oil of Zingiber anamalayanum from Western Ghats in India.

Volatile oil from fresh rhizomes of Zingiber anamalayanum was isolated by hydrodistillation and characterised by GC-FID and GC-MS. Twenty-one out of 24 constituents comprising 99.47% of the oil were identified. Major components in Z. anamalayanum rhizome oil were δ-2-carene (52.83%), camphene (9.83%), endo-fenchol (9.42%), iso-dihydrocarveol (6.44%) and cis-p-mentha-2,8-dien-1-ol (5.19%). Monoterpene hydrocarbons in the rhizome oil were 65.81%, followed by oxygenated monoterpenes (23.78%) and sesquiterpene hydrocarbons (9.87%). Physical parameters of rhizome oil were [Formula: see text] 1.4031, [Formula: see text] - 16.097(o) (c = 1, CHCl3) and [Formula: see text] 0.9202. Z. anamalayanum rhizome oil showed significant anti-Dalton's Lymphoma Ascitic activity.

Caryophyllene-rich rhizome oil of Zingiber nimmonii from South India: Chemical characterization and antimicrobial activity.

Volatile oil from the rhizomes of Zingiber nimmonii (J. Graham) Dalzell was isolated, characterized by analytical gas chromatography and gas chromatography-mass spectroscopy. Sixty-five constituents accounting for 97.5% of the oil were identified. Z. nimmonii rhizome oil is a unique caryophyllene-rich natural source with isomeric caryophyllenes, beta-caryophyllene (42.2%) and alpha-humulene (alpha-caryophyllene, 27.7%), as its major constituents along with traces of isocaryophyllene. The rhizome oil contained 71.2% sesquiterpenes, 14.2% oxygenated sesquiterpenes, 8.9% monoterpenes, 1.9% oxygenated monoterpenes and 1.3% non-terpenoid constituents. The antimicrobial activity of the oil was tested against human and plant pathogenic bacteria and fungi. The oil showed significant inhibitory activity against the fungi, Candida glabrata, C. albicans and Aspergillus niger and the bacteria Bacillus subtilis and Pseudomonas aeruginosa. No activity was observed against the fungus Fusarium oxysporum.

Composition and antimicrobial activity of essential oil from the fruits of Amomum cannicarpum.

Essential oil from the fruits of Amomum cannicarpum (Wight) Bentham ex Baker (Zingiberaceae) was hydrodistilled and characterized by gas chromatography-mass spectrometry (GC-MS). Major constituents of the oil were beta-pinene (14.00%), elemol (10.45%) and alpha-cadinol (8.50%). Thirty-three (91.48%) out of forty-one constituents were identified by GC-MS and subsequent data analysis. Antimicrobial activity of the oil against Gram-positive and Gram-negative bacteria and some fungi, was determined by the disc diffusion assay. The oil showed good antibacterial activity against Salmonella typhi, Pseudomonas aeruginosa and Proteus vulgaris and very good antifungal activity against Candida albicans and C. glabrata.

Chemical composition and antibacterial activity of the rhizome oil of Hedychium larsenii.

The composition of essential oil from the rhizomes of Hedychium larsenii M. Dan & Sathish was examined by GC-FID and GC-MS techniques. 99% of the oil consisted of monoterpenoids. Sesquiterpenoids were present only in negligible quantities. Linalool and 1,8-cineole were identified as the major components. The oil showed moderate antibacterial activity against Gram-positive and Gram-negative bacteria.