Effect of post-harvest drying period on the chemical composition of Zingiber zerumbet Sm. Rhizomes essential oil and its biological activities.

Zingiber zerumbet Sm. (Family: Zingiberaceae) is an important perennial medicinal oil-bearing herb that is native to the Southeast Asia. This study examines the impact of different durations of post-harvest shade drying (ranging from 1 to 12 months) on essential oil yield and chemical composition of Z. zerumbet, in comparison to the freshly collected oil sample. This study explores how post-harvest shade drying impact the composition and longevity of Z. zerumbet rhizomes as well as its antimicrobial, antibiofilm activity. The oils were analyzed for their chemical composition analysis using a gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). The post-harvest periods of drying (1-12 months) were discovered to enhance the concentration of marker constituents in the oil. The primary constituent, Zerumbone, was detected in concentrations ranging from 69.38 ± 5.63% to a maximum of 80.19 ± 1.53% as the drying duration of the rhizome was extended. The output of the essential oil was not significantly affected by drying times; however, it did have a noticeable impact on the proportions of monoterpenes. Both disc diffusion and broth microdilution assay were used in freshly collected Z. zerumbet oil for its antimicrobial potential against S. aureus, L. monocytogens, S. hominis, Salmonella enterica serovar Typhimurium, P. aeruginosa, S. intermedius, E. coli, and C. albicans. For the first time, the oil reported to exhibit antibiofilm activity against S. aureus which was validated using fluorescence microscopy, and effectively disrupts the biofilm by 47.38% revealing that essential oil was able to disintegrate the clusters of the pathogen. Z. zerumbet rhizome oil is effective to reduce food-borne microorganisms. Therefore, its essential oil, a natural source of bioactive zerumbone, may improve flavor, aroma, and preservation.

ACC deaminase-containing plant growth-promoting rhizobacteria protect Papaver somniferum from downy mildew.

AIMS: The aim of this study was to determine whether ACC (1-aminocyclopropane-1-carboxylic acid) deaminase-containing bacterial treatments could enhance the tolerance of poppy (Papaver somniferum L.) plants against biotic stress of downy mildew caused by Peronospora sp. METHODS AND RESULTS: Three different genotypes of P. somniferum, that is, Sampada, J-16 and I-14 were included in the experiment. The ACC deaminase-containing bacteria Pseudomonas putida (WPTe) reduced the downy mildew disease severity and significantly improved the growth and yield of P. somniferum plants. The chlorophyll content, photosynthetic rate, stomatal conductance and transpiration rate were modulated upon WPTe treatments in the poppy plants. We observed reduced synthesis of ethylene precursor (ACC) and abscisic acid (ABA), and enhanced production of indole acetic acid (IAA) in P. somniferum plants upon WPTe treatments. Moreover, WPTe treatment reduced proline and lipid peroxidation in plant leaves. CONCLUSION: These results highlight that the ACC deaminase-containing plant growth-promoting rhizobacteria (PGPR) enhance the tolerance of P. somniferum plant against downy mildew. SIGNIFICANCE AND IMPACT OF THE STUDY: ACC deaminase-containing PGPR may be used against phytopathogens which apart from protecting the plants from the disease could also be useful in reducing ethylene-induced damages in the event of abiotic stresses.

The role of a novel fungal strain Trichoderma atroviride RVF3 in improving humic acid content in mature compost and vermicompost via ligninolytic and celluloxylanolytic activities.

AIMS: With the rising concerns about indiscriminate use of chemical fertilizers and accumulation of agro-industrial wastes in huge quantities, the present experiment was conducted to elucidate the effect of a novel fungal strain of Trichoderma atroviride in hastening the compost/vermicompost production process and for the production of humic acid (HA) rich compost and vermicompost. METHODS AND RESULTS: Rice (Oryza sativa) straw and distillation waste of geranium (Pelargonium graveolens), two important agricultural/industrial crop wastes were subjected to composting and vermicomposting. T. atroviride strains GVF10 (cellulase and xylanase producing), and RVF3 (ligninase and celluloxylanase producing) were inoculated alone or in combination. The HA content was found to increase maximally in rice vermicompost treated with ligninase producing strain RVF3 (85% with respect to HA standard) followed by geranium vermicompost + RVF3. The addition of the strain GVF10 increased HA content to about 35-62% with respect to HA standard. The addition of the fungal inoculum reduced the composting/vermicomposting time from 110 to 90 days. CONCLUSIONS: Our results indicate that the use of selected fungal strain(s) hold potential to produce qualitatively superior compost and vermicompost with high HA content in a shorter period. SIGNIFICANCE AND IMPACT OF THE STUDY: Use of appropriate fungal strains may increase the efficiency of composting/vermicomposting processes producing compost and vermicompost with higher HA content, and alleviating the problems of solid waste accumulation and declining soil fertility.

Low-temperature perception and modulations in Ocimum basilicum commercial cultivar CIM-Shishir: Biosynthetic potential with insight towards climate-smart resilience.

The newly released interspecific hybrid variety CIM-Shishir, resulting from a cross between Ocimum basilicum and Ocimum kilimandscharicum claims to be a multicut, lodging resistant, cold tolerant, high essential oil yielding with linalool rich variety. It has a purple-green stem and has a unique feature and advantage of better survival in the winter season than other O. basilicum varieties, illustrating its physiological mechanisms for cold tolerance. In this study, we subjected both the CIM-Shishir variety and a control plant to cold stress to investigate the impact of low temperatures on various physiological, trichome developments, secondary metabolite constitution aspects related to essential oil production, and gene expression. The analysis revealed a significantly higher density and altered morphology of trichomes on the leaf surface of the variety subjected to low temperatures, indicating its adaptation to cold conditions. Furthermore, when comparing the treated plants under low-temperature stress, it was observed that the relative electrolyte leakage and Malondialdehyde (MDA) contents substantially increased in the control in contrast to the CIM-Shishir variety. This finding suggests that CIM-Shishir exhibits superior cold tolerance. Additionally, an increase in proline content was noted in the variety exposed to low temperatures compared to the control. Moreover, the chlorophyll and anthocyanin content gradually increased with prolonged exposure to low-temperature stress in the newly developed variety, indicating its ability to maintain photosynthetic capacity and adapt to cold conditions. The activities of superoxide dismutase (SOD) also increased under low-temperature conditions in the CIM-Shishir variety, further highlighting its cold tolerance behaviour. In our research, we investigated the comprehensive molecular mechanisms of cold response in Ocimum. We analyzed the expression of key genes associated with cold tolerance in two plant groups: the newly developed hybrid variety known as CIM-Shishir Ocimum, which exhibits cold tolerance, and the control plants susceptible to cold climates that include WRKY53, ICE1, HOS1, COR47, LOS15, DREB5, CBF4, LTI6, KIN, and ERD2. These genes exhibited significantly higher expression levels in the CIM-Shishir variety compared to the control, shedding light on the genetic basis of its cold tolerance. The need for climate-smart, resilient high-yielding genotype is of high importance due to varied climatic conditions as this will hit the yield drastically and further to the economic sectors including farmers and many industries that are dependent on the bioactive constituents of Ocimum.

A new source of elemol rich essential oil and existence of multicellular oil glands in leaves of the Dioscorea species.

Dioscorea species is a very important food and drug plant. The tubers of the plant are extensively used in food and drug purposes owing to the presence of steroidal constituent's diosgenin in the tubers. In the present study, we report for the first time that the leaves of Dioscorea composita and Dioscorea floribunda grown under the field conditions exhibited the presence of multicellular oil glands on the epidermal layers of the plants using stereomicroscopy (SM) and scanning electron microscopy (SEM). Essential oil was also isolated from the otherwise not useful herbage of the plant, and gas chromatographic-mass spectroscopy analysis revealed confirmation of the essential oil constituents. Out of the 76 compounds detected in D. floribunda and 37 from D. composita essential oil, major terpenoids which are detected and reported for Dioscorea leaf essential oil are α -terpinene, nerolidol, citronellyl acetate, farnesol, elemol, α -farnesene, valerenyl acetate, and so forth. Elemol was detected as the major constituent of both the Dioscorea species occupying 41% and 22% of D. Floribunda and D. composita essential oils, respectively. In this paper, we report for the first time Dioscorea as a possible novel bioresource for the essential oil besides its well-known importance for yielding diosgenin.

Synthesis and anticancer activity of 2-benzylidene indanones through inhibiting tubulin polymerization.

In an attempt to discover a potent and selective anticancer agent, gallic acid has been modified to benzylidene indanones as tubulin polymerization inhibitors. These compounds were evaluated against several human cancer cell lines and also evaluated for inhibition of tubulin polymerase in in vitro assays. Three of the analogues exhibited strong cytotoxicity against human cancer cell lines IC(50)=10-880 nM and also showed tubulin polymerization inhibition (IC(50)=0.62-2.04 µM). Compound 9j, the best candidate of the series was found to be non-toxic in acute oral toxicity in Swiss-albino mice up to 1000 mg/kg dose.

1-Chloro-2-formyl indenes and tetralenes as antitubercular agents.

1-Chloro-2-formyl indenes and tetralenes have been synthesized using Vilsmeier-Haack-Arnold reaction onto indanones and tetralones. Most of these analogues exhibited antitubercular activity against Mycobacterium tuberculosis H37Rv strain with MICs ranging from 30 to 500 µg/mL. Analogue 13 was further modified to some derivatives. The most active analogue 23 showing MIC at 30 µg/mL was further evaluated for acute oral toxicity in Swiss albino mice and was found to be safe up to 300 mg/kg dose.

Antitubercular potential of some semisynthetic analogues of phytol.

Phytol, a diterpene alcohol was modified to several semisynthetic analogues. Some of the modifications were done logically to enhance lipophilicity of the molecule. Analogues 14, 16 and 18 exhibited antitubercular activity (MIC 15.6-50microg/mL) better than phytol (100microg/mL). The most potent analogue 18 was evaluated for in vivo toxicity in Swiss albino mice and was well tolerated by the experimental animals up to 300mg/kg body weight as a single oral acute dose.

Gallic acid-based indanone derivatives as anticancer agents.

Gallic acid-based indanone derivatives have been synthesised. Some of the indanones showed very good anticancer activity in MTT assay. Compounds 10, 11, 12 and 14 possessed potent anticancer activity against various human cancer cell lines. The most potent indanone (10, IC(50)=2.2 microM), against MCF-7, that is, hormone-dependent breast cancer cell line, showed no toxicity to human erythrocytes even at higher concentrations (100 microg/ml, 258 microM). While, indanones 11, 12 and 14 showed toxicities to erythrocytes at higher concentrations.

Genetic elaborations of glandular and non-glandular trichomes in Mentha arvensis genotypes: assessing genotypic and phenotypic correlations along with gene expressions.

Mentha arvensis (corn mint) is well known for the production of menthol, a widely used commodity in pharma and flavoring industries and provides natural fragrances and products. Glandular trichomes are specialized hairs found on the aerial surface of vascular plants species producing specific secondary metabolite chemistry. Correlations were established among trichomes, oil yield, and major secondary metabolites. Nine improved, elite cultivars representing different M. arvensis genotypes were used for analysis. Phenotypic coefficient of variation (PCV) and genotypic coefficient of variation (GCV) were estimated; results indicated the presence of considerable amount of genetic variability, thereby emphasizing wide scope of selection. Positive and significant associations were found among glandular trichomes, oil yield, essential oil constituents, and leaf morphology itself, whereas morphological parameters of leaf show positive and negative correlations to average number of trichome and essential oil constituents. Average number of glandular, non-glandular trichomes, their ratios, menthol content, and trichome number showed a good heritability. Trichomes were studied microscopically in leaf parts in all varieties for analyzing their distribution pattern. The trichome number variations showed significant correlation throughout the genotypes with essential oil yield and monoterpenoid constituents. Differential changes were analyzed for Glutathione S-transferases, Glutathione reductase, Malondialdehyde, phenolics, and chlorophyll content. Gene expressions were analyzed for biosynthesis genes and selected transcription factors TRANSPARENT TESTA GLABRA 1 (TTG1), ENOLASE 1, GLABRA 3, GTL 1, NUCLEAR TRANSCRIPTION FACTOR Y SUBUNIT B-6, WRKY transcription factor 22, putative WRKY 33, WRKY 17, WRKY 1, and WRKY 65-like for harnessing their relation with trichome development in M. arvensis genotypes.

Synthesis of combretastatin A4 analogues on steroidal framework and their anti-breast cancer activity.

Combretastatin A4 analogues were synthesized on steroidal framework from gallic acid with a possibility of anti-breast cancer agents. Twenty two analogues were synthesized and evaluated for cytotoxicity against human breast cancer cell lines (MCF-7 & MDA-MB 231). The best analogue 22 showed potent antitubulin effect. Docking experiments also supported strong binding affinity of 22 to microtubule polymerase. In cell cycle analysis, 22 induced apoptosis in MCF-7 cells significantly. It was found to be non-toxic up to 300 mg/kg dose in Swiss albino mice in acute oral toxicity. This article is part of a Special Issue entitled "Synthesis and biological testing of steroid derivatives as inhibitors".

Investigation on phenylpropanoids rich Melaleuca decora (Salisb.) Britt. essential oil.

The essential oil of Melaleuca decora twigs has been obtained by hydrodistillation and analysed by GC-FID, GC/MS and (1)H-, (13)C-NMR experiments. The most abundant class of compounds in M. decora twig oil was phenylpropanoids represented by methyl eugenol (92.4%) as the most exclusive constituent. In terms of molecular diversity, phenylpropanoids dominate M. decora essential oil with low terpenoid (3.9%) proportion.

Gallic acid based steroidal phenstatin analogues for selective targeting of breast cancer cells through inhibiting tubulin polymerization.

Phenstatin analogues were synthesized on steroidal framework, for selective targeting of breast cancer cells. These analogues were evaluated for anticancer efficacy against breast cancer cell lines. Analogues 12 and 19 exhibited significant anticancer activity against MCF-7, hormone dependent breast cancer cell line. While analogues 10-14 exhibited significant anticancer activity against MDA-MB-231, hormone independent breast cancer cell line. Compound 10 showed significant oestrogen antagonistic activities with low agonistic activity in in vivo rat model. These analogues also retain tubulin polymerization inhibition activity. The most active analogue 10 was found to be non-toxic in Swiss albino mice up to 300 mg/kg dose. Gallic acid based phenstatin analogues may further be optimized as selective anti-breast cancer agents.

Terpenoid composition and antifungal activity of three commercially important essential oils against Aspergillus flavus and Aspergillus niger.

Hydro-distilled essential oils extracted from three commercially important aromatic plants were analysed by capillary gas chromatography-flame ionization detector and gas chromatography/quadrupole mass spectrometry and subjected to antifungal activity. Fifteen compounds, which accounted for 97.8% of Acorus calamus root oil composition have been identified. Besides the major constituent (Z)-asarone (81.1-92.4%), (Z)-methyl isoeugenol (1.8-2.1%), (Z)-isoelemicin (1.2-1.3%), (E)-asarone (1.0-2.6%), (E)-methyl isoeugenol (0.2-0.4%), (Z)-ß-ocimene (0.2-0.4%), elemicin (0.2-0.3%), linalool (0.1-0.9%) and kessane (t-0.2%) were identified. Monoterpenes constituted the main fraction of Origanum vulgare essential oil attaining 90.5% of the total oil composition. p-Cymene (10.3%) was the major component of the monoterpene hydrocarbon fraction while thymol (53.2%) and carvacrol (3.9%) were the most abundant oxygenated monoterpenes among the 33 identified constituents. Cinnamomum tamala leaf oil contained (E)-cinnamaldehyde as the principal component. Quantitative variations in (Z)-cinnamaldehyde (5.8-7.1%), linalool (6.4-8.5%) and (E)-cinnamyl acetate (4.7-5.2%) were significant. The antifungal activity of the hydro-distilled essential oils of A. calamus, O. vulgare and C. tamala were evaluated against Aspergillus flavus and Aspergillus niger. Disc diffusion method was used for the determination of the inhibitory effect. O. vulgare essential oil exhibited the highest activity. Moreover, all three essential oils inhibit the growth of A. flavus and A. niger.

Chemical investigation of the essential oil of Thymus linearis (Benth. ex Benth) from western Himalaya, India.

Thymus linearis (Benth. ex Benth) was collected from five distinct locations of western Himalaya (India) during the summer season. The hydro-distilled essential oil (yield 0.84-0.95%) was analysed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). A total of 56 constituents, representing 81.55% to 98.11% of the total oil composition, were identified. Thymol (52.28-66.65%), p-cymene (1.81-21.60%) and γ-terpinene (1.94-12.48%) were the major constituents in all populations. Other constituents identified in significant amounts were carvacrol, p-cymen-8-ol, borneol, terpinen-4-ol and thymol methyl ether. The presence of high phenol and essential oil contents in this species make it a suitable substitute for common thyme oil.