Search For Natural Products Research Articles

Inhibition of the Growth of Four Phytopathogenic Fungi by Eucalyptus Wood Vinegar

Purpose: The objective of this work aimed to assess the wood vinegar (WV) from the carbonization of Eucalyptus wood in the inhibition in vitro of Fusarium sp., Ganoderma sp., Macrophomina sp., and Sclerotium rolfsii. Method: WV was added to a culture medium and poured onto Petri dishes. After, the fungi were picked up in 1-mm disks and placed in the center of each Petri dish. The experimental design had five treatments, T1, T2, T3, T4, and T5, with crescent concentrations of WV, respectively, 0 (control), 5, 10, 15, and 20 mL L-1. The variables evaluated were fungal growth, mycelial growth rate index, and percentage of mycelial growth inhibition. Results and Discussion: A gradual decrease in the mycelial growth, in the mycelial growth rate index, and an increase in the percentage of mycelial growth inhibition were determined for all assessed fungi in the concentration of 20 mL L-1 of WV. Hence, the conclusion was that eucalyptus WV presented fungi-toxic properties over the assessed fungi and the product can be considered as an alternative for the chemical control of the incidence of these pathogens in crops and forest plantations. Research Implications: The use of natural products with fungi toxic properties is becoming important for the control of pathogens that attack crops and forest plantations due to the harmful effects of the conventional fungicides on living organisms and the environment. The search for efficient alternative products is therefore a goal to be reached in the field of phytopathology. Originality/ Value: The use of natural products with fungitoxic properties has been gaining ground in the control of pathogens affecting agricultural and forestry crops. This intensifies the search for natural products that are efficient in the biocontrol of phytopathologies.

Microcystis viridis NIES-102 Cyanobacteria Lectin (MVL) Interacts with SARS-CoV-2 Spike Protein Receptor Binding Domains (RBDs) via Protein-Protein Interaction.

The emergence of coronavirus disease 2019 (COVID-19) posed a major challenge to healthcare systems worldwide, especially as mutations in the culprit Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) complicated the development of vaccines and antiviral drugs. Therefore, the search for natural products with broad anti-SARS-CoV-2 capabilities is an important option for the prevention and treatment of similar infectious diseases. Lectins, which are widely recognized as antiviral agents, could contribute to the development of anti-SARS-CoV-2 drugs. This study evaluated the binding affinity of six lectins (including the cyanobacterial lectin from Microcystis viridis NIES-102 (MVL), and Jacalin, a lectin from the breadfruit, Artocarpus altilis) to the receptor binding domain (RBD) of the spike protein on the original (wild) SARS-CoV-2 and three of its mutants: Alpha, Delta, and Omicron. MVL and Jacalin showed distinct binding affinity to the RBDs of the four SARS-CoV-2 strains. The remaining four lectins (DB1, ConA, PHA-M and CSL3) showed no such binding affinity. Although the glycan specificities of MVL and Jacalin were different, they showed the same affinity for the spike protein RBDs of the four SARS-CoV-2 strains, in the order of effectiveness Alpha > Delta > original > Omicron. The verification of glycan-specific inhibition revealed that both lectins bind to RBDs by glycan-specific recognition, but, in addition, MVL binds to RBDs through protein-protein interactions.

Herbal Extracts for Hair Growth and Skin Rejuvenation: A Potential Solution for Hair Fall and Enhancing Skin Glow

Hair loss can have significant psychological and sociological impacts on individuals, affecting how they perceive themselves and are perceived by others. Globally, there has been a rise in the proportion of both men and women experiencing hair loss or thinning hair. Dermatological disorders, including alopecia, are common causes of hair loss, leading to a constant search for natural products that may promote hair growth. Several factors contribute to hair loss, including stress, major illnesses, medication use, depression, autoimmune diseases, family history, hormonal imbalances, and nutritional deficiencies. In India, approximately 50% of the population is experiencing hair loss at an accelerated rate, partly due to the use of inferior hair products in the beauty industry. Various herbs have been identified for their potential to promote skin renewal and hair development. These include Ficus religiosa, Ficus bengalensis, coriander seeds, rock sugar, and Chlorophytum borivilianum. These herbs contain nutritional components that can help manage hormonal imbalances and stimulate hair growth. Herbal formulations offer a natural and potentially effective solution for hair loss management. They can be tested for quality control and evaluation to ensure their safety and efficacy. These formulations may serve as immunoboosters or highly nutritious compositions, providing additional health benefits beyond hair care. Importantly, such remedies are typically associated with minimal or no negative side effects, making them a preferred option for individuals seeking natural approaches to address hair loss and related concerns.

Evaluation of Antitumor Activity of Xanthones Conjugated with Amino Acids.

Cancer is a complex disease characterized by several alterations, which confer, to the cells, the capacity to proliferate uncontrollably and to resist cellular death. Multiresistance to conventional chemotherapy drugs is often the cause of treatment failure; thus, the search for natural products or their derivatives with therapeutic action is essential. Chiral derivatives of xanthones (CDXs) have shown potential inhibitory activity against the growth of some human tumor cell lines. This work reports the screening of a library of CDXs, through viability assays, in different cancer cell lines: A375-C5, MCF-7, NCI-H460, and HCT-15. CDXs' effect was analyzed based on several parameters of cancer cells, and it was also verified if these compounds were substrates of glycoprotein-P (Pgp), one of the main mechanisms of resistance in cancer therapy. Pgp expression was evaluated in all cell lines, but no expression was observed, except for HCT-15. Also, when a humanized yeast expressing the human gene MDR1 was used, no conclusions could be drawn about CDXs as Pgp substrates. The selected CDXs did not induce significant differences in the metabolic parameters analyzed. These results show that some CDXs present promising antitumor activity, but other mechanisms should be triggered by these compounds.

Assessment of antimalarial activity of crude extract of Chan-Ta-Lee-La and Pra-Sa-Chan-Dang formulations and their plant ingredients for new drug candidates of malaria treatment: In vitro and in vivo experiments.

The emergence and spread of antimalarial drug resistance have become a significant problem worldwide. The search for natural products to develop novel antimalarial drugs is challenging. Therefore, this study aimed to assess the antimalarial and toxicological effects of Chan-Ta-Lee-La (CTLL) and Pra-Sa-Chan-Dang (PSCD) formulations and their plant ingredients. The crude extracts of CTLL and PSCD formulations and their plant ingredients were evaluated for in vitro antimalarial activity using Plasmodium lactate dehydrogenase enzyme and toxicity to Vero and HepG2 cells using the tetrazolium salt method. An extract from the CTLL and PSCD formulations exhibiting the highest selectivity index value was selected for further investigation using Peter's 4-day suppressive test, curative test, prophylactic test, and acute oral toxicity in mice. The phytochemical constituents were characterized using gas chromatography-mass spectrometry (GC-MS). Results showed that ethanolic extracts of CTLL and PSCD formulations possessed high antimalarial activity (half maximal inhibitory concentration = 4.88, and 4.19 g/mL, respectively) with low cytotoxicity. Ethanolic extracts of the CTLL and PSCD formulations demonstrated a significant dose-dependent decrease in parasitemia in mice. The ethanolic CTLL extract showed the greatest suppressive effect after 4 days of suppressive (89.80%) and curative (35.94%) testing at a dose of 600 mg/kg. Moreover, ethanolic PSCD extract showed the highest suppressive effect in the prophylactic test (65.82%) at a dose of 600 mg/kg. There was no acute toxicity in mice treated with ethanolic CTLL and PSCD extracts at 2,000 mg/kg bodyweight. GC-MS analysis revealed that the most abundant compounds in the ethanolic CTLL extract were linderol, isoborneol, eudesmol, linoleic acid, and oleic acid, whereas ethyl 4-methoxycinnamate was the most commonly found compound in the ethanolic PSCD extract, followed by 3-hydroxy-2-(4-hydroxy-3-methoxyphenyl)-4H-chromen-4-one, flamenol, oleic acid amide, linoleic acid, and oleic acid. In conclusions, ethanolic CTLL and PSCD extracts exhibited high antimalarial efficacy in vitro. The ethanolic CTLL extract at a dose of 600 mg/kg exhibited the highest antimalarial activity in the 4-day suppressive and curative tests, whereas the ethanolic PSCD extract at a dose of 600 mg/kg showed the highest antimalarial activity in the prophylactic test.

Current and emerging tools and strategies for the identification of bioactive natural products in complex mixtures.

Covering: up to 2024The prompt identification of (bio)active natural products (NPs) from complex mixtures poses a significant challenge due to the presence of numerous compounds with diverse structures and (bio)activities. Thus, this review provides an overview of current and emerging tools and strategies for the identification of (bio)active NPs in complex mixtures. Traditional approaches of bioassay-guided fractionation (BGF), followed by nuclear magnetic resonance (NMR) and mass spectrometry (MS) analysis for compound structure elucidation, continue to play an important role in the identification of active NPs. However, recent advances (2018-2024) have led to the development of novel techniques such as (bio)chemometric analysis, dereplication and combined approaches, which allow efficient prioritization for the elucidation of (bio)active compounds. For researchers involved in the search for bioactive NPs and who want to speed up their discoveries while maintaining accurate identifications, this review highlights the strengths and limitations of each technique and provides up-to-date insights into their combined use to achieve the highest level of confidence in the identification of (bio)active natural products from complex matrices.

Constituents of Uncaria lanosa f. philippinensis and their anti-amyloidogenic activity

The aggregation of amyloid-β (Aβ) remains the most acceptable pathological hallmark of Alzheimer’s disease (AD). In search for natural products exhibiting anti-amyloidogenic effects, phytochemical analyses were conducted on Uncaria lanosa f. philippinensis leading to the purification of oxindole alkaloid uncarine E (isopteropodine) (1), the phenylethanoid tyrosol (2), the megastigmane vomifoliol (3), and the previously reported alkaloids mitraphylline and isomitraphylline. This is the first report of compounds 1–3 in the title plant, and tyrosol (2) from the genus Uncaria. Assessment of the anti-amyloidogenic potential using Thioflavin T assay showed 91% (at 50 µM) and 70% (at 25 µM) inhibitions for compound 1. Tyrosol (2) gave 76% (at 50 µM) and 63% (at 25 µM) inhibitions. These compounds may be further tested to elucidate their mechanism in the prevention of Aβ aggregation. To the best of our knowledge, this is the first report on the anti-amyloid aggregation activity of compounds 1 and 2.

Neuroprotective Effects of Davallia mariesii Roots and Its Active Constituents on Scopolamine-Induced Memory Impairment in In Vivo and In Vitro Studies.

Beta-amyloid (Aβ) proteins, major contributors to Alzheimer's disease (AD), are overproduced and accumulate as oligomers and fibrils. These protein accumulations lead to significant changes in neuronal structure and function, ultimately resulting in the neuronal cell death observed in AD. Consequently, substances that can inhibit Aβ production and/or accumulation are of great interest for AD prevention and treatment. In the course of an ongoing search for natural products, the roots of Davallia mariesii T. Moore ex Baker were selected as a promising candidate with anti-amyloidogenic effects. The ethanol extract of D. mariesii roots, along with its active constituents, not only markedly reduced Aβ production by decreasing β-secretase expression in APP-CHO cells (Chinese hamster ovary cells which stably express amyloid precursor proteins), but also exhibited the ability to diminish Aβ aggregation while enhancing the disaggregation of Aβ aggregates, as determined through the Thioflavin T (Th T) assay. Furthermore, in an in vivo study, the extract of D. mariesii roots showed potential (a tendency) for mitigating scopolamine-induced memory impairment, as evidenced by results from the Morris water maze test and the passive avoidance test, which correlated with reduced Aβ deposition. Additionally, the levels of acetylcholine were significantly elevated, and acetylcholinesterase levels significantly decreased in the brains of mice (whole brains). The treatment with the extract of D. mariesii roots also led to upregulated brain-derived neurotrophic factor (BDNF) and phospho-cAMP response element-binding protein (p-CREB) in the hippocampal region. These findings suggest that the extract of D. mariesii roots, along with its active constituents, may offer neuroprotective effects against AD. Consequently, there is potential for the development of the extract of D. mariesii roots and its active constituents as effective therapeutic or preventative agents for AD.

Effect of Morinda citrifolia fruit powder on physiological and productive performance of Cavia porcellus.

The breeding of guinea pig is part of the pluriactivity for millions of farming families in rural areas from the Peruvian Andean and Amazonian regions and other South American Andean countries. Rearing these specie plays an important source of employment, income, and nutrition for millions of rural families on these countries. The search of natural products for enhancing animal wellbeing, health, and production and thereby of guinea pigs is being searched nowadays. The aim of this study was to determine the effect of the ripe fruit powder of Morinda citrifolia on the physiological and productive performance parameters of reared guinea pigs under humid tropical conditions and to find a new use of noni fruit and to improve the guinea pig as an agrifood product. For this purpose, forty-eight male Peru breed guinea pigs sixty days old, were used and distributed into four treatments with diets containing 0, 2, 4 and 8% of the noni ripe fruit powder, with four replicates and 3 guinea pigs each. Erythrocytes, hematocrit, hemoglobin profiles, hematological indices MCV (mean cell volume), MCHC (mean corpuscular hemoglobin concentration), MCH (mean corpuscular hemoglobin) and blood metabolites profiles: TP (total protein), ALB (albumin), GLO (globulin), TC (total cholesterol) were determined. The productive performance indices: DWG (daily weight gain), DCFI (daily concentrated feed intake), TFIFM (total feed intake of fresh matter) and TFIDM (total feed intake of dry matter), FRCFM (feed rate conversion for fresh mater) and FRCDM (feed rate conversion for dry matter) were evaluated. The guinea pigs were evaluated at 60, 75 and 90 days old. The interaction between noni fruit powder and the age of guinea pigs produced an increase in the erythrocyte, hematocrit, MCH and MCHC levels at 75 days old, (p < 0.05). The final weight and the daily weight gain increased, while the feed rate conversion for fresh and dry matter decreased, as the level of noni fruit powder in the diet increased until 4% (p < 0.05). Thus, the level of noni ripe fruit powder in the guinea pigs' diets had a positive effect on the erythrocyte, leucocytes, hematocrit, MCH, MCHC levels, the final weight, the daily weight gain, and the feed rate conversion of fresh and dry matter.

Inula viscosa L. (Asteraceae): A study on its antimicrobial and antioxidant activities, chromatographic fingerprinting profile

Food products contaminated with pathogens and spoiled not only lead to a decrease in the quality and quantity of food products but also contribute to the spread of diseases, which are increasingly becoming a public health problem in both developed and developing countries. Due to the multiple resistance of these pathogens to antibiotics, the search for natural products with antimicrobial properties is becoming increasingly important. Inula viscosa has been used as a medicinal plant for a long time in many Mediterranean countries. The aim of this study was to investigate the antimicrobial effects of I. viscosa extracts against foodborne pathogens and their non-enzymatic antioxidant potential. Antimicrobial activity was measured using the disc diffusion method. Additionally, plant extracts were tested against 2,2-Diphenyl-1-picrylhydrazyl and 2,2'-azinobis (3-ethyl-benzothiazoline 6-sulfonate) radicals for antioxidant activity. Inula viscosa showed the highest antibacterial activity against Bacillus subtilis with the methanol extract (19 mm zone diameter), while the lowest activity was observed against Salmonella Typhimurium, with inhibition zone diameters of 7 mm. The highest antioxidant activity was recorded as 77.5% for the DPPH• method and 73.8% for the ABTS• method. In conclusion, this plant can be considered a natural antimicrobial and antioxidant agent against foodborne pathogens, and it is a promising candidate for large-scale experiments.

The Effects of Andrographis paniculata (Burm.F.) Wall. Ex Nees and Andrographolide on Neuroinflammation in the Treatment of Neurodegenerative Diseases.

Neurodegenerative diseases (NDs) affect millions of people worldwide, and to date, Alzheimer's and Parkinson's diseases are the most common NDs. Of the many risk factors for neurodegeneration, the aging process has the most significant impact, to the extent that it is tempting to consider neurodegenerative disease as a manifestation of accelerated aging. However, genetic and environmental factors determine the course of neurodegenerative disease progression. It has been proposed that environmental stimuli influence neuroplasticity. Some clinical studies have shown that healthy lifestyles and the administration of nutraceuticals containing bioactive molecules possessing antioxidant and anti-inflammatory properties have a preventive impact or mitigate symptoms in previously diagnosed patients. Despite ongoing research efforts, the therapies currently used for the treatment of NDs provide only marginal therapeutic benefits; therefore, the focus is now directly on the search for natural products that could be valuable tools in combating these diseases, including the natural compound Andrographis paniculata (Ap) and its main constituent, andrographolide (Andro). Preclinical studies have shown that the aqueous extract of Ap can modulate neuroinflammatory and neurodegenerative responses, reducing inflammatory markers and oxidative stress in various NDs. Therefore, in this review, we will focus on the molecular mechanisms by which Ap and Andro can modulate the processes of neurodegeneration and neuroinflammation, which are significant causes of neuronal death and cognitive decline.

Probiotics and prebiotics in dairy farming

The search for natural products that favor productive performance in animal feed has been gaining strength with probiotics, prebiotics and symbiotics that constitute an alternative for mastitis control. The action of these products is in the competition with unwanted microorganisms, stimulating the beneficial microbiota, in addition to favoring a greater development in the intestinal villi, which can provide a better absorption of nutrients. These compounds are an alternative to treatment with antibiotics that have caused the emergence of resistant microorganisms, in addition to causing sensory changes in milk and its derivatives. Through this study, it was possible to verify the importance of this class of substance for dairy farming and for unique health in general.

Recent bioanalytical methods for the isolation of bioactive natural products from genus Codonopsis.

Chromatography and spectroscopy are nowadays well-validated techniques allowing to isolate and purify different class of natural products from the genus Codonopsis. Several categories of phytochemicals with drug like properties have been selectively extracted, isolated, characterised by this methodology. The present review aims to provide up-to-date and comprehensive information on the chromatography, phytochemistry and pharmacology of natural products of Codonopsis with an emphasis on the search for natural products having various biological activities and the semi-synthetic derivatives of bioactive ones and to highlight current gaps in knowledge. A literature search was performed in the SciFinder Scholar, PubMed, Medline, and Scopus databases. During the period covered in this review, several classes of compounds have been reported from genus Codonopsis. Codonopsis pilosula and Codonopsis lanceolata are the most popular in the genus especially as per phytochemical and bioactive studies. Phytochemical investigation demonstrates that Codonopsis species contain mainly xanthones, flavonoids, alkaloids, polyacetylenes, phenylpropanoids, triterpenoids and polysaccharides, which contribute to numerous bioactivities. The major bioactive compounds isolated were used for semi-synthetic modification to increase the chance to discover lead compound. It can be concluded that genus Codonopsis has been used as traditional medicines and food materials around the world over years due to chemical constituents with diverse structural types, exhibiting extensive pharmacological activities in immune system, blood system, cardiovascular system, central nervous system, digestive system, and so forth, with almost no obvious toxicity and side effect. Therefore, Codonopsis can be used as a promising ethnopharmacological plant source.

Nutritional and Ethno-Medicinal Potentials of Egg-Lime-Molasses Mixture in Livestock Production

Background: The quest for organic agriculture has necessitated the search for natural products which are abundant in phytochemicals and have significant therapeutic effects. This study was carried out to investigate the nutritional and ethno-medicinal potentials of egg-lime-molasses mixture (ELM). Methods: Fresh eggs were placed in a bowl after which 1 liter of lime juice and 500 g of molasses were added into the same bowl, then it was covered tightly and left for 10 days at temperature of 27°C and relative humidity of 61%. At the end of 10 days, the egg shells were dissolved into solution and then blended together. The mixture was then analyzed for proximate composition, phytochemicals, minerals and vitamins. The analyses were investigated in accordance with standard procedures. Result: Proximate analysis of ELM indicated the presence of moisture content (19.60%), crude protein (15.20%), lipids (5.50%), ash (14.60%), crude fibre (9.60%), carbohydrates (35.20%), fatty acid (4.40%) and energy (1060.30 Kcal/100 kg). Phytochemical screening revealed that ELM contained alkaloids, flavonoids, glycosides, saponin, steroids, phenols, terpenoides, tannin and antraquinones. Quantitative evaluation of the phytochemicals showed that ELM contained alkaloids (8.46 mg/100 g), flavonoids (2.30 mg/100 g), glycosides (0.08 mg/100g), Saponin (5.25 mg/100 g), steroids (0.22 mg/l00 g), phenols (0.09 mg/100 g), terpenoides (0.56 mg/100 g), tannin (8.34 mg/100g) and antraquinones (1.60 mg/100 g) and the vitamin constituents are Vitamin A (3.20 mg/100 g), Vitamin B1(280 mg/100 g), Vitamin B2 (880 mg/100 g), Vitamin B3 (340 mg/100 g), Vitamin C (15.40 mg/100 g) and Vitamin E (0.015 mg/100 g). Mineral analysis showed that it contained calcium (29.95%), magnesium (4.08%), potassium (23.20%), sodium (0.38%), phosphorus (6.90%), chlorine (0.30%), manganese (1.44 ppm), iron (3.60 ppm), aluminum (5.35%), titanium (2.10 ppm) and silicon (22.70 ppm). It was concluded that ELM is rich in various nutrients and phytochemicals conferring it the ability to perform multiple biological activities and as a natural alternative to antibiotics especially in monogastric animal production.

English

Many studies have dealt with the medicinal properties of Jatropha curcas; however, there are limited studies on the scope of its antiviral potential. This is a fact associated with the current challenges posed by HIV-AIDS and COVID-19, which has reinforced the need to expand the knowledge about its antiviral resource. Based on the search for natural products with anti-HIV-1 and anti-SARS-CoV-2 activities, this work analyzed the extract of J. curcas seed, the structure of the plant whose antiviral references were not found in the literature, and the compounds that can potentiate it as a candidate for herbal medicine. GC-MS analysis was used to screen for the active substances of the J. curcas seeds, and the literature was searched to find those with anti-HIV-1 and anti-SARS-CoV-2 indication. The results showed they have 27 compounds, of which glycerol 1-palmitate, stigmasterol and gamma-sitosterol were shown to have antiviral action in the literature. Regarding glycerol 1-palmitate, no detailed description of its antiviral action was found. Stigmasterol and gamma-sitosterol act as anti-HIV-1 and anti-SARS-CoV-2, respectively, inhibiting the reverse transcriptase of HIV-1, the proteases 3CLpro, PLpro and the spike proteins of SARS-CoV-2. However, despite the fact that the extract of J. curcas seeds consist of antiviral compounds that fight against the etiological agents of HIV-AIDS and COVID-19, it is concluded that there is a need to deepen this evidence, by in vitro and in vivo assays. Key words: Compounds, antivirals, Jatropha curcas, HIV, SARS-CoV-2.

The Antimicrobial Activity of Curcumin and Xanthohumol on Bacterial Biofilms Developed over Dental Implant Surfaces.

In search for natural products with antimicrobial properties for use in the prevention and treatment of peri-implantitis, the purpose of this investigation was to evaluate the antimicrobial activity of curcumin and xanthohumol, using an in vitro multi-species dynamic biofilm model including Streptococcus oralis, Actinomyces naeslundii, Veillonella parvula, Fusobacterium nucleatum, Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans. The antimicrobial activities of curcumin (5 mM) and xanthohumol (100 μM) extracts, and the respective controls, were evaluated with 72-h biofilms formed over dental implants by their submersion for 60 seconds. The evaluation was assessed by quantitative polymerase chain reaction (qPCR), confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). For the data analysis, comparisons were tested applying ANOVA tests with post-hoc Bonferroni corrections to evaluate the antimicrobial activity of both extracts. With qPCR, statistically significant reductions in bacterial counts were observed for curcumin and xanthohumol, when compared to the negative control. The results with CLSM and SEM were consistent with those reported with qPCR. It was concluded that both curcumin and xanthohumol have demonstrated antimicrobial activity against the six bacterial species included in the dynamic in vitro biofilm model used.

The Anti-Tubercular Aminolipopeptide Trichoderin A Displays Selective Toxicity against Human Pancreatic Ductal Adenocarcinoma Cells Cultured under Glucose Starvation.

Pancreatic ductal adenocarcinoma remains a highly debilitating condition with no effective disease-modifying interventions. In our search for natural products with promising anticancer activity, we identified the aminolipopeptide trichoderin A as a potential candidate. While it was initially isolated as an antitubercular peptide, we provide evidence that it is also selectively toxic against BxPC-3 and PANC-1 human pancreatic ductal adenocarcinoma cells cultured under glucose deprivation. This has critical implications for the pancreatic ductal adenocarcinoma, which is characterized by nutrient deprivation due to its hypovascularized network. We have also successfully simplified the trichoderin A peptide backbone, allowing greater accessibility to the peptide for further biological testing. In addition, we also conducted a preliminary investigation into the role of peptide lipidation at the N-terminus. This showed that analogues with longer fatty acyl chains exhibited superior cytotoxicity than those with shorter acyl chains. Further structural optimization of trichoderin A is anticipated to improve its biological activity, whilst ongoing mechanistic studies to elucidate its intracellular mechanism of action are conducted in parallel.

The Exploration of Microbial Natural Products and Metabolic Interaction Guided by Mass Spectrometry Imaging.

As an impressive mass spectrometry technology, mass spectrometric imaging (MSI) can provide mass spectra data and spatial distribution of analytes simultaneously. MSI has been widely used in diverse fields such as clinical diagnosis, the pharmaceutical industry and environmental study due to its accuracy, high resolution and developing reproducibility. Natural products (NPs) have been a critical source of leading drugs; almost half of marketed drugs are derived from NPs or their derivatives. The continuous search for bioactive NPs from microorganisms or microbiomes has always been attractive. MSI allows us to analyze and characterize NPs directly in monocultured microorganisms or a microbial community. In this review, we briefly introduce current mainstream ionization technologies for microbial samples and the key issue of sample preparation, and then summarize some applications of MSI in the exploration of microbial NPs and metabolic interaction, especially NPs from marine microbes. Additionally, remaining challenges and future prospects are discussed.

Evaluation of Essential Oils as Spatial Repellents Against Aedes aegypti in an Olfactometer.

Spatial repellents are becoming an integral part of the integrated mosquito management and are considered another tool to prevent mosquito-borne diseases. They are also gaining attention as a potential disease transmission breaking strategy. Current vector control practices are losing their viability due to resistance development in arthropods to synthetic pesticides. Economic feasibility of developing natural products is driving towards search for natural products as spatial repellents evidenced by increase in number of their studies. Different volumes (0.0625, 0.125, 0.25, 0.5 ml) of clove oil, eucalyptus oil, geraniol, Immortelle oil, lemongrass oil, and RepelCare (mixture of turmeric oil and eucalyptus oil) were evaluated for their repellency against Aedes aegypti, replicating each test 5 times. Biogents lure and fresh air were used as control. The evaluations were conducted in a True Choice olfactometer by passing air carrying 2 vapors from 2 different products, i.e., an attractant, repellent, or clean air, through 2 chambers and providing mosquitoes an option to move to the chamber of their choice. For each run, 24-h-starved 15-20 female Ae. aegypti were released into the mosquito release chamber and number of mosquitoes in the 2-choice chambers and the mosquito release chamber were counted after 15 min and recorded. The difference in mosquitoes between 2 chambers indicated presence or absence of repellency. All the natural oils and RepelCare provided ≥70% repellency, except for Immortelle oil which had no repellency. All repellents tested except Immortelle and lemongrass oils showed increase in repellency with increase in application volume. However, minimum application volume to be effective was different for each oil. Lemongrass is the only oil which showed a peak at 0.125-ml volume.

In silico analysis of koranimine, a cyclic imine compound from Peribacillus frigoritolerans reveals potential nematicidal activity

Pine wilt disease (PWD) is a destructive vector-borne forest disease caused by the nematode Bursaphelenchus xylophilus. To date, several options are available for the management of pine wilt disease; however constant development and search for natural products with potential nematicidal activity are imperative to diversify management options and to cope with the possible future emergence of resistance in parasitic nematodes. Here, a combined metabolomics and genomics approach was employed to investigate the chemical repertoire and biosynthetic potential of the bacterial endophyte Peribacillus frigoritolerans BE93, previously characterized to exhibit nematicidal activity against B. xylophilus. Feature-based molecular networking revealed the presence of diverse secondary metabolites. A cyclic imine heptapeptide, koranimine, was found to be among the most abundant secondary metabolites produced. Genome mining displayed the presence of several putative biosynthetic gene clusters (BGCs), including a dedicated non-ribosomal peptide synthase (NRPS) BGC for koranimine. Given the non-ribosomal peptide nature of koranimine, in silico molecular docking analysis was conducted to investigate its potential nematicidal activity against the target receptor ivermectin-sensitive invertebrate α glutamate-gated chloride channel (GluCl). Results revealed the binding of koranimine at the allosteric site of the channel—the ivermectin binding site. Moreover, the ligand-receptor interactions observed were mostly shared between koranimine and ivermectin when bound to the α GluCl receptor thus, suggesting a possibly shared mechanism of potential nematicidal activity. This study highlights the efficiency of combined metabolomics and genomics approach in the identification of candidate compounds.