Antifungal activity of liquiritin in Phytophthora capsici comprises not only membrane-damage-mediated autophagy, apoptosis, and Ca2+ reduction but also an induced defense responses in pepper

Effect and Mechanism of Patchouli Alcohol for the Management of Postharvest Green Pepper Fruit Rot Caused by Alternaria alternata

Green pepper, a commonly cultivated vegetable, often suffers from fruit rot caused by Alternaria alternata, which reduces its quality and shelf life. In this study, the antifungal activity and mechanism of patchouli alcohol (PA), which was isolated from Pogostemon cablin essential oil, against A. alternata during the storage of green peppers, were investigated. PA effectively inhibited the growth of A. alternata in vitro and in vivo assays, reduced lesion areas, and extended the storage life of green peppers. Scanning and transmission electron microscopy revealed that PA induced significant morphological deformations in A. alternata hyphae, inhibited spore germination, and disrupted the cellular structures. Transcriptomic, proteomic, and physiological analyses suggested that PA impaired cell membrane synthesis and function, disrupted mitochondrial activity, and induced oxidative stress, resulting in cellular dysfunction and apoptosis. These actions significantly suppressed A. alternata growth, ultimately prolonging the shelf life of the green peppers. This study provides the potential use of PA for green pepper preservation.

Dexmedetomidine regulates the anti-oxidation and autophagy of adipose-derived stromal cells under H2O2-induced oxidative stress through Nrf2/p62 pathway and improves the retention rate of autologous fat transplantation

To investigate the protective mechanism of dexmedetomidine (DEX) on adipose-derived stromal cells (ADSCs) under oxidative stress model and its promotion effect on the retention rate of adipose granule transplantation by in vitro and in vivo experiments. The experiment was divided into control group, model group (ADSCs + H2O2+normal serum), DEX group (ADSCs + H202+DEX drug-containing serum), autophagy agonist group (ADSCs + H2O2+rapamycin (RAP)+normal serum), RAP + DEX group (ADSCs + H2O2+normal serum), RAP + DEX drug-containing serum), autophagy inhibitor group (ADSCs + H2O2+chloroquine (CQ)+normal serum), CQ + DEX group (ADSCs + H2O2+CQ + DEX drug-containing serum). HO-1, GSH-PX, SOD and CAT in ADSCs under oxidative stress model were measured. ROS fluorescence intensity and apoptosis ratio were detected. Expression of Nrf2, LC3-II/LC3-I and p62 were detected. In vivo, fat mixed with ADSCs or DEX -pretreated ADSCs was implanted subcutaneously in the lower back region of nude mice. Fat grafts were collected and analyzed at 2-, 4-, 6-, and 8-weeks post-transplantation. DEX pretreatment could reduce the expression of p62 to enhance the autophagy level of ADSCs under oxidative stress model. Additionally, cotransplantation of DEX-pretreated ADSCs with fat improved the long-term texture of fat grafts. DEX increased the fat graft survival and angiogenesis.

Antagonistic Effects and Volatile Organic Compound Profiles of Rhizobacteria in the Biocontrol of Phytophthora capsici

Phytophthora capsici is a devastating pathogen in horticultural crops, particularly affecting Capsicum annuum (pepper). The overuse of chemical fungicides has led to resistance development, necessitating alternative strategies. This study investigates the antagonistic effects of four rhizobacterial isolates (Bacillus sp., Pseudomonas putida, Bacillus subtilis, Bacillus amyloliquefaciens) against P. capsici, focusing on the production of volatile organic compounds (VOCs). Using in vitro dual culture assays, we observed a significant inhibition of mycelial growth and sporangia production, especially by B. subtilis and B. amyloliquefaciens. The GC-MS/SPME-HS analysis identified key VOCs responsible for these antagonistic effects. Our findings demonstrate that specific rhizobacteria and their VOCs offer a promising biocontrol strategy, potentially reducing the reliance on chemical fungicides and contributing to sustainable agriculture.

Biocontrol of rusted root rot in Panax ginseng by a combination of extracts from Bacillus amyloliquefaciens YY8 crude protein and Enterobacteriaceae YY115 ethyl acetate

BACKGROUND

Rusted root rot is one of the most common root diseases in Panax ginseng, and Cylindrocarpon destructans is one of the main pathogenic fungus. The objective of this study was to screen and explore the extracts of biocontrol bacteria isolated from ginseng rhizosphere soil against Cylindrocarpon destructans.

RESULTS

Bacterial strains Bacillus amyloliquefaciens YY8 and Enterobacteriacea YY115 were isolated and found to exhibit in vitro antifungal activity against C. destructans. A combination of crude protein extract from B. amyloliquefaciens YY8 and ethyl acetate extract from Enterobacteriacea YY115 in a 6:4 ratio exhibited the strongest antifungal activity against C. destructans. Measurements of electrical conductivity, protein content, and nucleic acid content in suspension cultures of C. destructans treated with a mixture extracts indicated that the extracts disrupted the cell membranes of rusted root rot mycelia, resulting in the leakage of electrolytes, proteins, and nucleic acids from the cells, and ultimately inhibiting the growth of C. destructans. The combined extracts suppressed the infection of ginseng roots discs by C. destructans effectively.

CONCLUSION

The extracts obtained from the two bacterial strains effectively inhibited C. destructans in P. ginseng. It can provide scientific basis for the development of new biological control pesticides, reduce the use of chemical pesticides, and promote the sustainable development of agriculture.

Preservation effect of Lactobacillus plantarum O2 fermentation supernatant on postharvest pepper and its induced resistance to Phytophthora capsici

Research of lactic acid bacteria and its metabolites on biological preservatives becomes a hot topic. Lactobacillus plantarum O2, with good inhibition on Phytophthora capsici (P. capsici), was isolated from the pickle. In this study, the effects of L. plantarum O2 fermentation supernatant (FS) on pepper postharvest preservation and its induced resistance to P. capsici were studied. Results showed that weight loss rate, rot index, respiration rate, relative electrical conductivity, loss of chlorophyll content and VC of pepper in FS treatment group were decreased by 18 %, 64 %, 15 %, 26 %, 33 % and 20 % compared with blank control (BC) after 20 d storage. L* and b*-value of pepper in FS group were lower than those in the BC group. In addition, the damage-induced resistance test found that the infection rate in the FS group was reduced by 39 %, compared with CK2 after 12 d storage. Moreover, phenylalanine ammonia-lyase activity, peroxidase activity, polyphenol oxidase activity, proline content, total phenol content and flavonoid content increased by 14 %, 9 %, 30 %, 8 %, 8 % and 9 %, respectively, while malondialdehyde content decreased by 13 %. These results indicated that FS treatment showed good fresh-keeping effects on postharvest pepper. It could enhance the tolerance of pepper under stress by improving defensive enzyme activities, slowing down the damage caused by P. capsici, and inducing pepper resistance to P. capsici. Therefore, FS can be used as a microbial source bio-preservative for postharvest pepper.

Effects and mechanisms of plant bioactive compounds in preventing fungal spoilage and mycotoxin contamination in postharvest fruits: A review

Spoilage and mycotoxin contamination of fruits cause significant economic losses and food safety issues. Synthetic chemical fungicide treatment as primary postharvest management has attracted increasing public concern in recent years, because it may cause negative effects on the environment and human health. Numerous bioactive compounds from plants have demonstrated excellent control effects on fruit spoilage and mycotoxin contamination. Plant bioactive compounds have been considered one of the most promising alternatives, because they are generally regarded as safe and environmentally friendly. Here, we reviewed the most recent advances in plant bioactive compounds in the prevention of fungal spoilage and mycotoxin contamination in fruits. The control effects of these compounds and the mechanisms involved were summarized, and current limitations and future perspectives were discussed.

Antimicrobial mechanisms and secondary metabolite profiles of Streptomyces hygroscopicus subsp. hygroscopicus 5-4 against banana fusarium wilt disease using metabolomics

Fusarium wilt of bananas (FWB) is seriously affecting the sustainable development of the banana industry and is caused by the devastating soil-borne fungus Fusarium oxysporum f. sp. cubense tropical race 4 (Foc TR4). Biological control is a promising strategy for controlling Fusarium wilt in bananas. We previously identified Streptomyces hygroscopicus subsp. hygroscopicus 5-4 with strong antifungal activity against the FWB. The most possible antimicrobial mechanism of strain 5-4 was explored using the metabolomics approach, light microscopy imaging, and transmission electron microscopy (TEM). The membrane integrity and ultrastructure of Foc TR4 was damaged after extract treatment, which was supported by the degradation of mycelium, soluble protein content, extracellular reducing sugar content, NADH oxidase activity, malondialdehyde content, mitochondrial membrane potential, and mitochondrial respiratory chain complex enzyme activity. The extracts of strain 5-4 cultivated at different times were characterized by a liquid chromatography-mass spectrometer (LC-MS). 647 known metabolites were detected in the extracts of strains 5-4. Hygromycin B, gluten exorphin B4, torvoside G, (z)-8-tetradecenal, piperitoside, sarmentosin, pubescenol, and other compounds were the main differential metabolites on fermentation culture for 7 days. Compared with strain 5-4 extracts, hygromycin B inhibited the mycelial growth of Foc TR4, and the EC₅₀ concentration was 7.4 μg/mL. These results showed that strain 5-4 could destroy the cell membrane of Foc TR4 to inhibit the mycelial growth, and hygromycin B may be the key antimicrobial active metabolite. Streptomyces hygroscopicus subsp. hygroscopicus 5-4 might be a promising candidate strain to control the FWB and provide a scientific basis for the practical application of hygromycin B as a biological control agent.

Evaluation of Inhibitory Effect and Mechanism of Euphorbia Factor L3 against Phytophthora capsici

Phytophthora capsici is a highly destructive phytopathogenic oomycete with a broad host range and is responsible for tremendous losses. Euphorbia factor L3 (EFL3) is a natural plant-derived compound that has been widely studied in medicine and cosmetic applications. In this study, the sensitivity of 105 P. capsici isolates to EFL3 was determined, and the biological activity and physiological effects of EFL3 against P. capsici were investigated. The median effective concentration (EC50) values for EFL3 inhibition mycelial growth and spore germination ranged from 0.66 to 8.94 μg/mL (mean, 2.96 ± 0.91 μg/mL) and 1.63 to 13.16 μg/mL (mean, 5.30 ± 1.64 μg/mL), respectively. EFL3 treatment resulted in cell wall and cell membrane damage of P. capsici, which was revealed by morphological and ultrastructural observations, propidium iodide (PI) and calcofluor white (CFW) staining, and measurements of relative conductivity as well as malondialdehyde (MDA) and glycerol contents. In addition, the contents of phospholipid and cellulose, which are the major components of cell membrane and cell wall, were significantly reduced following EFL3 treatment. Furthermore, EFL3 provided protective as well as curative efficacies against P. capsici on detached tomato leaves and pepper seedlings in vivo. These data show that EFL3 exhibits strong inhibitory activity against P. capsici, thereby suggesting that it could be an effective alternative for controlling P. capsici-induced diseases.

Potential inhibitory activity of phytoconstituents against black fungus: In silico ADMET, molecular docking and MD simulation studies

Mucormycosis or “black fungus” has been currently observed in India, as a secondary infection in COVID-19 infected patients in the post-COVID-stage. Fungus is an uncommon opportunistic infection that affects people who have a weak immune system. In this study, 158 antifungal phytochemicals were screened using molecular docking against glucoamylase enzyme of Rhizopus oryzae to identify potential inhibitors. The docking scores of the selected phytochemicals were compared with Isomaltotriose as a positive control. Most of the compounds showed lower binding energy values than Isomaltotriose (-6.4 kcal/mol). Computational studies also revealed the strongest binding affinity of the screened phytochemicals was Dioscin (-9.4 kcal/mol). Furthermore, the binding interactions of the top ten potential phytochemicals were elucidated and further analyzed. In-silico ADME and toxicity prediction were also evaluated using SwissADME and admetSAR online servers. Compounds Piscisoflavone C, 8-O-methylaverufin and Punicalagin exhibited positive results with the Lipinski filter and drug-likeness and showed mild to moderate of toxicity. Molecular dynamics (MD) simulation (at 300 K for 100 ns) was also employed to the docked ligand-target complex to explore the stability of ligand-target complex, improve docking results, and analyze the molecular mechanisms of protein-target interactions.

Haizao Yuhu decoctions including three species of glycyrrhiza protected against propylthiouracil-induced goiter with hypothyroidism in rats via the AMPK/mTOR pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Glycyrrhiza and sargassum are among the 18 incompatible medicaments according to traditional Chinese medicine (TCM) theory. Although it contains glycyrrhiza and sargassum, Haizao Yuhu decoction (HYD) is a classic prescription widely used as TCM to treat goiter. According to the Chinese Pharmacopoeia, glycyrrhiza is divided into three varieties: Glycyrrhiza uralensis Fish., Glycyrrhiza glabra L., and Glycyrrhiza inflata Bat. Whether the three varieties of glycyrrhiza have different efficacy or toxicity when applied in the HYD is unknown.

AIM OF THE STUDY

To explore whether the HYDs comprising three varieties of glycyrrhiza have different efficacy or toxicity when used to treat goiter in rats and the underlying mechanisms of these HYDs.

MATERIALS AND METHODS

For two weeks, the goiter model was replicated by intragastric propylthiouracil (PTU) administration. Samples were divided into the control group, model group, euthyrox group, HYD with glycyrrhiza uralensis (HYD-U) group, HYD with glycyrrhiza glabra (HYD-G) group, and HYD with glycyrrhiza inflata (HYD-I) group. After four weeks of treatment, body weight, rectal temperature, thyroid/liver/kidney coefficient, thyroid/liver/kidney function, thyroid/liver/kidney histomorphology, and thyroid ultrastructure were evaluated. Then, real-time quantitative reverse-transcription polymerase chain reaction (RTqPCR), Western blot, and immunofluorescence analyses were performed to detect genes and proteins affecting autophagy and apoptosis in thyroid cells in the AMP-activated Protein Kinases (AMPK)/Mammalian target of rapamycin (mTOR) pathway.

RESULTS

All three HYDs increased thyroid hormones (THs) levels, relieved thyroid pathological tissue and ultrastructure, and activated vital proteins and genes in the AMPK/mTOR pathway. Comparisons among the efficacy of the three HYDs indicated that HYD-U restored the THs most effectively; however, no difference in the anti-goiter effect was observed. Moreover, the three HYDs resulted in no toxicity and promoted the recovery of impaired liver and kidney function caused by PTU. Comparisons among the recovery effects of the three HYDs on the liver and kidney were the same.

CONCLUSION

Our experiments demonstrated that the three HYDs had outstanding anti-goiter effects and protected liver and kidney function. Their anti-goiter effects were attributed to AMPK/mTOR pathway-induced autophagy and apoptosis. HYD-U resulted in the best THs recovery. It was further indicated that in our present study, glycyrrhiza and sargassum were compatible in the three HYDs, thereby suggesting their safety of compounding in HYD and providing a basis for the research of the 18 incompatible medicaments.

Antimicrobial Terpenes Suppressed the Infection Process of Phytophthora in Fennel-Pepper Intercropping System

The interactions between non-host roots and pathogens may be key to the inhibition of soilborne pathogens in intercropping systems. Fennel (Foeniculum vulgare) can be intercropped with a wide range of other plants to inhibit soilborne pathogens in biodiversity cultivation. However, the key compounds of fennel root exudates involved in the interactions between fennel roots and pathogens are still unknown. Here, a greenhouse experiment confirmed that intercropping with fennel suppressed pepper (Capsicum annuum) blight disease caused by Phytophthora capsici. Experimentally, the roots and root exudates of fennel can effectively interfere with the infection process of P. capsici at rhizosphere soil concentrations by attracting zoospores and inhibiting the motility of the zoospores and germination of the cystospores. Five terpene compounds (D-limonene, estragole, anethole, gamma-terpenes, and beta-myrcene) that were identified in the fennel rhizosphere soil and root exudates were found to interfere with P. capsica infection. D-limonene was associated with positive chemotaxis with zoospores, and a mixture of the five terpene compounds showed a strong synergistic effect on the infection process of P. capsici, especially for zoospore rupture. Furthermore, the five terpene compounds can induce the accumulation of reactive oxygen species (ROS), especially anethole, in hyphae. ROS accumulation may be one of the antimicrobial mechanisms of terpene compounds. Above all, we proposed that terpene compounds secreted from fennel root play a key role in Phytophthora disease suppression in this intercropping system.

Pharmacological Effects and Underlying Mechanisms of Licorice-Derived Flavonoids

Glycyrrhizae Radix et Rhizoma is the most frequently prescribed natural medicine in China and has been used for more than 2,000 years. The flavonoids of licorice have garnered considerable attention in recent decades due to their structural diversity and myriad pharmacological effects, especially as novel therapeutic agents against inflammation and cancer. Although many articles have been published to summarize different pharmacological activities of licorice in recent years, the systematic summary for flavonoid components is not comprehensive. Therefore, in this review, we summarized the pharmacological and mechanistic data from recent researches on licorice flavonoids and their bioactive components.

Endophytic Bacterial Communities of Ginkgo biloba Leaves During Leaf Developmental Period

Plant-specialized secondary metabolites have ecological functions in mediating interactions between plants and their entophytes. In this study, high-throughput gene sequencing was used to analyze the composition and abundance of bacteria from Ginkgo leaves at five different sampling times. The results indicated that the bacterial community structure varied during leaf developmental stage. Bacterial diversity was observed to be the highest at T2 stage and the lowest at T1 stage. Proteobacteria, Firmicutes, Actinobacteria, Chloroflexi, Cyanobacteria, and Bacteroidetes were found as the dominant phyla. The major genera also showed consistency across sampling times, but there was a significant variation in their abundance, such as Bacillus, Lysinibacillus, and Staphylococcus. Significant correlations were observed between endophytic bacteria and flavonoids. Especially, Staphylococcus showed a significant positive correlation with quercetin, and changes in the abundance of Staphylococcus also showed a strong correlation with flavonoid content. In order to determine the effect of flavonoids on endophytic bacteria of Ginkgo leaves, an extracorporeal culture of related strains (a strain of Staphylococcus and a strain of Deinococcus) was performed, and it was found that the effect of flavonoids on them remained consistent. The predicted result of Tax4Fun2 revealed that flavonoids might lead to a lower abundance of endophytic microorganisms, which further proved the correlation between bacterial communities and flavonoids. This study provided the first insight into the bacterial community composition during the development of Ginkgo leaves and the correlation between the endophytic bacteria and flavonoids.

Liquiritin from Radix Glycyrrhizae Protects Cardiac Mitochondria from Hypoxia/Reoxygenation Damage

AIMS

The purpose of this study was to evaluate the protective effect of liquiritin (LIQ) from Radix Glycyrrhizae on cardiac mitochondria against hypoxia/reoxygenation (HR) injury.

METHODS

H9C2 cells were subject to the HR model. LIQ purified from Radix Glycyrrhizae (purity > 95%) was administrated to reoxygenation period. Cell viability, mitochondrial mass, mitochondrial membrane potential, reactive oxygen species, and mitochondrial Ca2⁺ level were then assessed by using Cell Counting kit-8 and suitable fluorescence probe kits.

RESULTS

LIQ administration remarkably reduced the rate of HR damage via increasing H9C2 cell viability level and preserving mitochondria after HR. Particularly, 60 μM of LIQ posthypoxic treatment markedly reduced cell death in HR-subjected H9C2 cell groups (p < 0.05). Interestingly, posthypoxic treatment of LIQ significantly prevented the loss of mitochondrial membrane potential, the decrease in mitochondrial mass, the increase in reactive oxygen species production, and the elevation of mitochondrial Ca2⁺ level in HR-treated H9C2 cells.

CONCLUSION

The present study provides for the first time the cardioprotective of LIQ posthypoxic treatment via reducing H9C2 cell death and protecting cardiac mitochondria against HR damage.