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1.
Fitoterapia ; 175: 105931, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38608733

ABSTRACT

Pararorine A, a new isoindolinone alkaloid was isolated from Paramyrothecium roridum, an endophytic fungus from the medicinal plant Gynochthodes officinalis (F.C. How) Razafim. & B. Bremer. The structure of this compound was elucidated by extensive spectroscopic (UV, IR, MS, and NMR) analyses. In addition, the antitumor activity of pararorine A was evaluated against SF-268, MCF-7, HepG2, and A549 tumor cell lines. The results revealed that pararorine A exhibited potent antitumor activities with the IC50 values ranging from 1.69 to 8.95 µM. Moreover, the tumor cell inhibitory activity of pararorine A was evidenced by promoting cytochrome C release and cell cycle arrest as well as the induction of apoptosis by the up-regulation of the protein expressions of JNK and Bax through PARP-cleavage and caspase 3-cleavage.


Subject(s)
Apoptosis , Humans , Molecular Structure , Cell Line, Tumor , Apoptosis/drug effects , Endophytes/chemistry , Alkaloids/pharmacology , Alkaloids/isolation & purification , Alkaloids/chemistry , Antineoplastic Agents/pharmacology , Antineoplastic Agents/isolation & purification , Antineoplastic Agents/chemistry , Cell Cycle Checkpoints/drug effects , China
2.
Fitoterapia ; 175: 105952, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38614405

ABSTRACT

Three new xanthone derivatives irpexols A-C (1-3) and five known xanthones including three dimeric ones were successfully isolated from Irpex laceratus A878, an endophytic fungus of the family Irpicaceae from the medicinal plant Pogostemon cablin (Blanco) Bentham (Lamiaceae). The structures of these compounds were elucidated by extensive spectroscopic analyses including ultraviolet-visible spectroscopy (UV), infrared spectroscopy (IR), mass spectrometry (MS), and nuclear magnetic resonance (NMR). All of the three new compounds (1-3) share a de-aromatic and highly­oxygenated xanthone skeleton. In addition, the cytotoxic activity of compounds 1-8 were evaluated against SF-268, MCF-7, HepG2, and A549 tumor cell lines. The results revealed that compound 6 showed moderate cytotoxic activity with the IC50 values ranging from 24.83 to 45.46 µM, while the IC50 values of the positive control adriamycin was ranging from 1.11 to 1.44 µM.


Subject(s)
Endophytes , Xanthones , Xanthones/isolation & purification , Xanthones/pharmacology , Xanthones/chemistry , Molecular Structure , Humans , Endophytes/chemistry , Cell Line, Tumor , Pogostemon/chemistry , Antineoplastic Agents/pharmacology , Antineoplastic Agents/isolation & purification , Antineoplastic Agents/chemistry , China
3.
Compr Rev Food Sci Food Saf ; 23(1): e13273, 2024 01.
Article in English | MEDLINE | ID: mdl-38284599

ABSTRACT

Rosemary (Rosmarinus officinalis L.) is one of the most famous spice plants belonging to the Lamiaceae family as a remarkably beautiful horticultural plant and economically agricultural crop. The essential oil of rosemary has been enthusiastically welcome in the whole world for hundreds of years. Now, it is wildly prevailing as a promising functional food additive for human health. More importantly, due to its significant aroma, food, and nutritional value, rosemary also plays an essential role in the food/feed additive and food packaging industries. Modern industrial development and fundamental scientific research have extensively revealed its unique phytochemical constituents with biologically meaningful activities, which closely related to diverse human health functions. In this review, we provide a comprehensively systematic perspective on rosemary by summarizing the structures of various pharmacological and nutritional components, biologically functional activities and their molecular regulatory networks required in food developments, and the recent advances in their applications in the food industry. Finally, the temporary limitations and future research trends regarding the development of rosemary components are also discussed and prospected. Hence, the review covering the fundamental research advances and developing prospects of rosemary is a desirable demand to facilitate their better understanding, and it will also serve as a reference to provide many insights for the future promotion of the research and development of functional foods related to rosemary.


Subject(s)
Oils, Volatile , Rosmarinus , Humans , Plant Extracts/chemistry , Rosmarinus/chemistry , Food Additives , Functional Food , Oils, Volatile/pharmacology , Plants
4.
Fitoterapia ; 173: 105751, 2024 Mar.
Article in English | MEDLINE | ID: mdl-37977303

ABSTRACT

Three new α-pyrone derivatives cytospotones A-C (1-3) and a new cyclohexenone derivative cytospotone D (4) together with four known α-pyrones were isolated from the endophytic fungus Cytospora sp. A879 of Pogostemon cablin (Blanco) Benth. The structures of 1-4 were elucidated primarily by spectroscopic methods (1D, 2D NMR and HRESIMS), ECD spectra analyses, and ECD calculations. Furthermore, the four new compounds (1-4) were evaluated for their anti-inflammatory and α-glucosidase inhibitory activities. The results showed that compound 1 had moderate inhibitory effect on LPS-induced NO production in RAW 264.7 macrophages.


Subject(s)
Ascomycota , Pogostemon , Molecular Structure , Ascomycota/chemistry , Magnetic Resonance Spectroscopy , Pyrones
5.
Fitoterapia ; 172: 105772, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38064922

ABSTRACT

Three new compounds phomtersines A-C (1-3) together with nine known compounds were isolated from the marine-derived fungus Phomopsis tersa FS441. Their structures were sufficiently established by spectroscopic methods, including extensive 1D and 2D NMR techniques and modified Snatzke's method. Moreover, compounds 1-12 were evaluated for cytotoxic and anti-inflammatory activities. As a result, phomtersine B (2) and the known compound 10 showed moderate cytotoxic activity against the four tested cell lines with IC50 values ranging from 20.21 to 36.53 µM, and phomtersine A (1) exhibited moderate inhibitory activity against LPS-induced NO production.


Subject(s)
Antineoplastic Agents , Ascomycota , Cell Line, Tumor , Molecular Structure , Ascomycota/chemistry , Antineoplastic Agents/pharmacology , Indoles/metabolism
6.
Zhongguo Zhen Jiu ; 43(7): 793-9, 2023 Jul 12.
Article in Chinese | MEDLINE | ID: mdl-37429659

ABSTRACT

OBJECTIVE: To observe the effects of Yizhi Tiaoshen (benefiting mental health and regulating the spirit) acupuncture on learning and memory function, and the expression of phosphorylated tubulin-associated unit (tau) protein in the hippocampus of Alzheimer's disease (AD) model rats, and explore the effect mechanism of this therapy on AD. METHODS: A blank group and a sham-operation group were randomly selected from 60 male SD rats, 10 rats in each one. AD models were established in the rest 40 rats by the intraperitoneal injection of D-galactose and okadaic acid in the CA1 region of the bilateral hippocampus. Thirty successfully-replicated model rats were randomly divided into a model group, a western medication group and an acupuncture group, 10 rats in each one. In the acupuncture group, acupuncture was applied to "Baihui" (GV 20), "Sishencong" (EX-HN 1), "Neiguan" (PC 6), "Shenmen" (HT 7), "Xuanzhong" (GB 39) and "Sanyinjiao" (SP 6); and the needles were retained for 10 min. Acupuncture was given once daily. One course of treatment was composed of 6 days, with the interval of 1 day; the completion of treatment included 4 courses. In the western medication group, donepezil hydrochloride solution (0.45 mg/kg) was administrated intragastrically, once daily; it took 7 days to accomplish one course of treatment and a completion of intervention was composed of 4 courses. Morris water maze (MWM) and novel object recognition test (NORT) were used to assess the learning and memory function of the rats. Using HE staining and Nissl staining, the morphological structure of the hippocampus was observed. With Western blot adopted, the protein expression of the tau, phosphorylated tau protein at Ser198 (p-tau Ser198), protein phosphatase 2A (PP2A) and glycogen synthase kinase-3ß (GSK-3ß) in the hippocampus was detected. RESULTS: There were no statistical differences in all of the indexes between the sham-operation group and the blank group. Compared with the sham-operation group, in the model group, the MWM escape latency was prolonged (P<0.05), the crossing frequency and the quadrant stay time in original platform were shortened (P<0.05), and the NORT discrimination index (DI) was reduced (P<0.05); the hippocampal cell numbers were declined and the cells arranged irregularly, the hippocampal neuronal structure was abnormal and the numbers of Nissl bodies decreased; the protein expression of p-tau Ser198 and GSK-3ßwas increased (P<0.05) and that of PP2A decreased (P<0.05). When compared with the model group, in the western medication group and the acupuncture group, the MWM escape latency was shortened (P<0.05), the crossing frequency and the quadrant stay time in original platform were increased (P<0.05), and DI got higher (P<0.05); the hippocampal cell numbers were elevated and the cells arranged regularly, the damage of hippocampal neuronal structure was attenuated and the numbers of Nissl bodies were increased; the protein expression of p-tau Ser198 and GSK-3ß was reduced (P<0.05) and that of PP2A was increased (P<0.05). There were no statistically significant differences in the above indexes between the acupuncture group and the western medication group (P>0.05). CONCLUSION: Acupuncture therapy of "benefiting mental health and regulating the spirit" could improve the learning and memory function and alleviate neuronal injure of AD model rats. The effect mechanism of this therapy may be related to the down-regulation of GSK-3ß and the up-regulation of PP2A in the hippocampus, and then to inducing the inhibition of tau protein phosphorylation.


Subject(s)
Acupuncture Therapy , Alzheimer Disease , Male , Animals , Rats , Rats, Sprague-Dawley , Glycogen Synthase Kinase 3 beta , Tubulin , Alzheimer Disease/genetics , Alzheimer Disease/therapy , tau Proteins/genetics , Hippocampus
7.
Fitoterapia ; 169: 105572, 2023 Sep.
Article in English | MEDLINE | ID: mdl-37315718

ABSTRACT

Two undescribed citrinin derivatives, named peniciriols A-B (1-2), together with six known compounds were isolated from endophytic fungus Penicillum citrinum TJNZ-27. The structures of two new compounds were well established by the detail interpretation of NMR and HRESIMS data as well as ECD measurement powered by molecular calculation. Among them, compound 1 shared an unprecedented dimerized citrinin skeleton with the formation of an intriguing 9H-xanthene ring system, whereas compound 2 possess a highly substituted phenylacetic acid skeleton, which was rarely-occurring in natural secondary metabolites. Moreover, these novel compounds were tested for cytotoxic and antibacterial activities, whereas these novel compounds did not exhibit any noticeable cytotoxic or antibacterial activities.


Subject(s)
Citrinin , Penicillium , Molecular Structure , Penicillium/chemistry , Anti-Bacterial Agents , Fungi
8.
Front Plant Sci ; 14: 1144406, 2023.
Article in English | MEDLINE | ID: mdl-37063184

ABSTRACT

Lobelia species, as rich source of the alkaloid lobeline which has been shown to have important biological activity, have been used in folk medicine throughout East Asia to treat various diseases. However, Lobelia is a complex and varied genus in East Asia and is thus difficult to identify. Genomic resources would aid identification, however the availability of such information is poor, preventing a clear understanding of their evolutionary history from being established. To close this gap in the available genomic data, in this study, 17 plastomes of East Asian lobelias were newly sequenced and assembled. Although the plastomes of Lobelia sect. Hypsela, L. sect. Speirema, and L. sect. Rhynchopetalum shared the gene structure, the inverted repeat (IR)/large single copy (LSC) boundaries, genome size, and the number of repeats were variable, indicating the non-conservative nature of plastome evolution within these sections. However, the genomes of the Lobelia sect. Delostemon and L. sect. Stenotium showed rearrangements, revealing that these two sections might have undergone different evolutionary histories. We assessed nine hotspot genes and 27-51 simple sequence repeat motifs, which will also serve as valuable DNA barcode regions in future population genetics studies and for the delineation of plant species. Our phylogenetic analysis resolved the evolutionary positions of the five sections in agreement with previous evolutionary trees based on morphological features. Although phylogenetic reconstruction of Lobelioideae based on the rpoC2 gene has rarely been performed, our results indicated that it contains a considerable amount of phylogenetic information and offers great promise for further phylogenetic analysis of Lobelioideae. Our site-specific model identified 173 sites under highly positive selections. The branch-site model exhibited 11 positive selection sites involving four genes in the East Asian branches. These four genes may play critical roles in the adaptation of East Asian taxa to diverse environments. Our study is the first to detect plastome organization, phylogenetic utility, and signatures of positive selection in the plastomes of East Asian lobelias, which will help to further advance taxonomic and evolutionary studies and the utilization of medicinal plant resources.

9.
Food Chem ; 411: 135423, 2023 Jun 15.
Article in English | MEDLINE | ID: mdl-36652884

ABSTRACT

Psidium guajava L. is one of the most pivotal members belong to the Myrtaceae family, and it is an important tropical fruit with highly nutritional, healthy, and pharmacological values prevailing in worldwide for decades. The polysaccharides of P. guajava (PGPs) are served as one of the most active constituents, which possess a variety of biofunctionalities including anti-inflammatory, antidiarrheic, antihypertension, and antidiabetic properties. Hence, a systematic review aimed to comprehensively summarize the recent research advances of PGPs is necessary for facilitating their better understanding. The present review discussed current research progress on the PGPs, including extraction and purification methods, structural features, biological activities, and potential pharmacological mechanism. In addition, this review may also provide some valuable insights for further development and potential value in affording functionally useful agents in food industry or therapeutically effective medicine in the fields of P. guajava polysaccharides.


Subject(s)
Myrtaceae , Psidium , Psidium/chemistry , Plant Extracts/pharmacology , Plant Extracts/analysis , Hypoglycemic Agents/analysis , Plant Leaves/chemistry , Polysaccharides/pharmacology , Polysaccharides/analysis
10.
J Colloid Interface Sci ; 630(Pt A): 385-394, 2023 Jan 15.
Article in English | MEDLINE | ID: mdl-36265340

ABSTRACT

Design of nanovectors inspired by nature is a short cut to improve the efficacy and bioavailability of chemotherapeutic agents, while reduce the toxicity. In this work, strongly hydrophobic camptothecin (CPT) was modified with different chain length of fatty acid (C4, C9 and C18) to synthesize CPT4C, CPT9C and CPT18C, respectively. CPT4C, CPT9C and CPT18C could complex with human serum albumin (HSA) readily to prepare CPT4C-HSA, CPT9C-HSA and CPT18C-HSA nanoagents. In vitro MTT assays demonstrated CPT18C-HSA possessed the highest cell killing capacity, due to the elevated cellular uptake that resulted from albumin-mediated transportation. In vivo tumor inhibition experiments verified that CPT18C-HSA had the most remarkable antitumor efficiency with distinctly lowered physiological toxicity. It could be used in large doses without obvious side effects. We believe this albumin-mediated transportation mode has great potential for efficient delivery of hydrophobic and/or physiologically unstable drugs.


Subject(s)
Antineoplastic Agents , Camptothecin , Humans , Camptothecin/pharmacology , Camptothecin/chemistry , Biomimetics , Fatty Acids , Serum Albumin, Human , Antineoplastic Agents/pharmacology
11.
Biomater Sci ; 11(1): 195-207, 2022 Dec 20.
Article in English | MEDLINE | ID: mdl-36411987

ABSTRACT

Cancer phototheranostics that combines diagnosis with phototherapy has emerged as a new mode of precise treatment. Nevertheless, taking highly effective phototheranostics into consideration, it is still a tremendous challenge to design multifunctional photothermal agents (PTAs) that combine the features of intensive near-infrared (NIR) absorption/emission, high photothermal conversion efficiency (PCE) and preferable tumor accumulation. Herein, seeking a convenient method to facilitate absorption red-shift, promote the accumulation of drugs in tumors and heighten the PCE appears to be particularly important for cancer theranostics. In this work, heavy-atom-free boron dipyrromethene (BODIPY) was assembled with F127 to fabricate ultra-small J-aggregated nanoparticles (named as BNPs). Compared to free BODIPY, BNPs exhibited 63 nm redshifted absorption, deep-tissue fluorescence imaging, enhanced cellular uptake, preferable tumor accumulation, elevated PCE, excellent photothermal stability and water dispersibility. In vivo experiments demonstrated that BNPs could behave as high-performance tumor fluorescent imaging probes and antitumor PTAs to conduct NIR imaging-guided PTT. This work offers a novel J-aggregated framework on developing robust diagnostic and therapeutic agents.


Subject(s)
Nanoparticles , Neoplasms , Humans , Boron , Theranostic Nanomedicine/methods , Neoplasms/diagnostic imaging , Neoplasms/drug therapy , Cell Line, Tumor
12.
Fitoterapia ; 163: 105324, 2022 Nov.
Article in English | MEDLINE | ID: mdl-36216139

ABSTRACT

Cytospones E-J (1-6), six unreported α-pyrone derivatives, together with six known ones (7-12) were isolated from the solid culture of the endophytic fungus Cytospora rhizophorae A761, an endophytic fungus from Gynochthodes officinalis. The structures of the unreported compounds were unambiguously elucidated through spectroscopic analyses (1D, 2D NMR and HRESIMS), and their absolute configurations were assigned by single-crystal X-ray diffraction (Cu Kα) analyses. Furthermore, cytospones E-J were evaluated for anti-inflammatory and α-glucosidase inhibitory activities.


Subject(s)
Ascomycota , Molecular Structure , Ascomycota/chemistry , Crystallography, X-Ray , Pyrones
13.
Chin J Nat Med ; 19(11): 874-880, 2021 Nov.
Article in English | MEDLINE | ID: mdl-34844726

ABSTRACT

Nine new compounds, including five natural rarely-occurring 2, 3-dihydro-1H-indene derivatives named diaporindenes E-I (1-5), and four new benzophenone analogues named tenellones J-M (6-9) were isolated from the deep-sea sediment-derived fungus Phomopsis lithocarpus FS508. All the structures for these new compounds were fully characterized on the basis of spectroscopic data, NMR spectra, and ECD calculation and single-crystal X-ray diffraction analysis. The potential anti-tumor activities of compounds 1-9 against four tumor cell lines SF-268, MCF-7, HepG-2, and A549 were evaluated using the SRB method. Compound 7 exhibited cytotoxic activity against the SF-268 cell line with an IC50 value of 11.36 µmol·L-1.


Subject(s)
Antineoplastic Agents , Phomopsis , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Crystallography, X-Ray , Fungi , Molecular Structure
14.
Fitoterapia ; 147: 104768, 2020 Nov.
Article in English | MEDLINE | ID: mdl-33166597

ABSTRACT

The chemical investigation of the secondary metabolites of Paramyrothecium roridum (homotypic synonym: Myrothecium roridum), an endophytic fungus isolated from the medicinal plant Morinda officinalis, led to the isolation of twelve cytotoxic trichothecene macrolides, including two new ones, named myrothecines H and I. The structures of the new macrolides were elucidated by extensive spectroscopic measurements analyses. In addition, the cytotoxic activities of these compounds were evaluated against SF-268, NCI-H460, and HepG-2 tumor cell lines, and all isolated compounds (1-12) exhibited significant cytotoxic activity with the IC50 ranging from 0.0002-16.2 µM. Moreover, the inhibitory activity of myrothecines H and I was evidenced by inducing phosphorylation of JNK (c-Jun N-terminal protein kinase) protein and the PARP (poly ADP-ribose polymerase) cleavage, and eventually induce apoptosis of HepG-2 cells. The results indicated that myrothecines H and I could be applied as chemotherapeutic agents.


Subject(s)
Antineoplastic Agents/pharmacology , Biological Products/pharmacology , Hypocreales/chemistry , Macrolides/pharmacology , Trichothecenes/pharmacology , Antineoplastic Agents/isolation & purification , Apoptosis , Biological Products/isolation & purification , China , Endophytes/chemistry , Hep G2 Cells , Humans , Macrolides/isolation & purification , Molecular Structure , Morinda/microbiology , Trichothecenes/isolation & purification
15.
Fitoterapia ; 137: 104260, 2019 Sep.
Article in English | MEDLINE | ID: mdl-31284016

ABSTRACT

One new benzophenone derivative, named tenllone I (1), two new eremophilane derivatives lithocarins B (2) and C (3), and a new monoterpentoid lithocarin D (4), together with two know compounds (5 and 6) were isolated from the endophytic fungus Diaporthe lithocarpus A740. All of the structures for these new compounds were fully characterized and established on the basis of extensive spectroscopic interpretation. In addition, all the isolated compounds were evaluated in vitro for their cytotoxic activity. Compounds 2, 3, and 5 showed weak inhibitory activities against tumor cell lines.


Subject(s)
Ascomycota/chemistry , Benzophenones/isolation & purification , Antineoplastic Agents/isolation & purification , Antineoplastic Agents/pharmacology , Benzophenones/pharmacology , Cell Line, Tumor , China , Endophytes/chemistry , Humans , Molecular Structure , Morinda/microbiology
16.
Chin J Nat Med ; 17(5): 381-386, 2019 May 20.
Article in English | MEDLINE | ID: mdl-31171273

ABSTRACT

Three new prenylated stilbenes, named as cajanusins A-C (1-3), and one new natural product cajanusin D (4), along with six known derivatives (5-10) were isolated from the leaves of Cajanus cajan. Their structures were fully elucidated by means of extensive spectroscopic methods and comparison with data in the reported literatures. The new compounds of 1 and 2 were evaluated for in vitro cytotoxic activities against a panel of human cancer cell lines.


Subject(s)
Antineoplastic Agents, Phytogenic/chemistry , Cajanus/chemistry , Flavonoids/chemistry , Stilbenes/chemistry , Antineoplastic Agents, Phytogenic/isolation & purification , Antineoplastic Agents, Phytogenic/toxicity , Cell Line, Tumor , Cell Survival/drug effects , Drug Screening Assays, Antitumor , Flavonoids/isolation & purification , Humans , Molecular Structure , Plant Extracts/chemistry , Plant Leaves/chemistry , Stilbenes/isolation & purification , Stilbenes/toxicity
17.
Fitoterapia ; 134: 264-269, 2019 Apr.
Article in English | MEDLINE | ID: mdl-30825577

ABSTRACT

Five new compounds including two stilbenes, designated thujasutchins A (1) and B (2), two phenolic compounds namely thujasutchins C (3) and D (4), as well as one sesquiterpene thujasutchin E (5), were isolated from the 95% ethanolic extract from the trunks and roots of Thuja sutchuenensis. Their structures were determined by means of extensively spectroscopic analysis including UV, IR, HRESIMS, 1H and 13C NMR (COSY, HSQC, HMBC). Moreover, compounds 1, 3-5 were evaluated for in vitro cytotoxic activities against SF-268, MCF-7, HepG-2, and A549 tumor cell lines.


Subject(s)
Sesquiterpenes/chemistry , Stilbenes/chemistry , Thuja/chemistry , Cell Line, Tumor , China , Humans , Molecular Structure , Phytochemicals/chemistry , Phytochemicals/isolation & purification , Plant Roots/chemistry , Sesquiterpenes/isolation & purification , Stilbenes/isolation & purification
18.
Fitoterapia ; 133: 125-129, 2019 Mar.
Article in English | MEDLINE | ID: mdl-30599185

ABSTRACT

Two pairs of novel enantiomeric flavonoids (1a, 1b and 2a, 2b), along with one new lignan (3), were isolated from the aerial parts of Abrus precatorius. All of these enantiomeric flavonoids featured an unprecedented propylated flavonoid skeleton representing a new family of flavonoid, and the new lignan was found to have an attractive arachidate ester side chain. Their structures were extensively elucidated by means of detailed NMR and mass spectroscopic analysis. Moreover, biological evaluation of antibacterial activity for these compounds against Bacillus cereus and Escherichia coli were conducted.


Subject(s)
Abrus/chemistry , Flavonoids/chemistry , Lignans/chemistry , Plant Components, Aerial/chemistry , Anti-Bacterial Agents , China , Flavonoids/isolation & purification , Lignans/isolation & purification , Molecular Structure , Phytochemicals/chemistry , Phytochemicals/isolation & purification
19.
J Ethnopharmacol ; 228: 50-57, 2019 Jan 10.
Article in English | MEDLINE | ID: mdl-30195566

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: The leaves of Rhodomyrtus tomentosa are traditionally used in the treatment of infectious diseases such as wound infections in Chinese traditional medicine. The mechanisms of the activity of rhodomyrtosone B (RDSB), a natural acylphloroglucinol isolated from the leaves of Rhodomyrtus tomentosa, are still not understood. We provided a detailed investigation of the antibacterial action of RDSB against bacteria in vitro and in vivo. MATERIALS AND METHODS: The antibacterial activity of RDSB was tested by the microdilution method against a panel of bacteria, and a time-killing assay was carried out according to CLSI guidelines. The cytotoxic potential of RDSB was evaluated against mammalian cells, and its haemolytic activity towards rabbit red blood cells (RBCs) was assessed. The mode of action of RDSB was investigated by targeting bacterial membranes, and its resistance was evaluated using a sequential passaging method. The antibacterial activities in vivo were assessed against MRSA in a mouse skin infection mode. RESULTS: RDSB exhibited distinct antibacterial activities against selected Gram-positive pathogens responsible for serious infections, even including methicillin-resistant Staphylococcus aureus (MRSA) with a minimum inhibitory concentration (MIC) of 0.62-1.25 µg/mL and vancomycin-resistant Enterococcus faecium (VRE) with an MIC of 2.5 µg/mL. RDSB displayed much more rapid bactericidal activity against MRSA than that of vancomycin. The membrane-targeting experiments revealed that RDSB exhibited significant antibacterial activity with the perturbation of bacterial membrane potential and an increase in membrane permeability. In particular, RDSB had weak cytotoxicity to mammalian cells (IC50 >14 µg/mL) and has advantageous specificity against selected Gram-positive bacterial membranes rather than RBCs. Notably, RDSB displayed in vitro antibacterial activities against MRSA without drug-resistance and profoundly attenuated the skin ulcer formation in a murine model of MRSA infection under a single dose of 40 µg RDSB per mouse. CONCLUSION: RDSB has profound antibacterial activity against drug-resistant bacteria (MRSA and VRE) and low cytotoxicity. It is bactericidal in nature, and an increase in membrane permeability resulting from membrane perturbation is one of its modes of action. RDSB represents a promising natural antibiotic to combat drug-resistant (MRSA and VRE) infections.


Subject(s)
Anti-Bacterial Agents/therapeutic use , Heterocyclic Compounds, 3-Ring/therapeutic use , Methicillin-Resistant Staphylococcus aureus/drug effects , Staphylococcal Infections/drug therapy , Animals , Anti-Bacterial Agents/pharmacology , Cell Line , Erythrocytes/drug effects , Female , Heterocyclic Compounds, 3-Ring/pharmacology , Methicillin-Resistant Staphylococcus aureus/growth & development , Mice, Inbred BALB C , Microbial Sensitivity Tests , Myrtaceae , Phytotherapy , Rabbits
20.
J Asian Nat Prod Res ; 21(2): 150-156, 2019 Feb.
Article in English | MEDLINE | ID: mdl-29063789

ABSTRACT

The chemical investigation of the mycelia of endophytic fungus Daldinia eschscholtzii A630, which was isolated from the medicinal plant Pogostemon cablin, resulted in the isolation of two new compounds, named eschscholin A (1), 3-ene-2-methyl-2H-1-benzopyran-5-ol (2), and one new natural product 3,5-dihydroxy-2-methyl-4H-chromen-4-one (3), along with seven known compounds. Their structures were fully characterized by means of detailed spectroscopic analysis, and in comparison with published data for known compounds. All of the isolated compounds (1-10) were evaluated for their antibacterial activities.


Subject(s)
Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Pogostemon/microbiology , Xylariales/chemistry , Escherichia coli/drug effects , Microbial Sensitivity Tests , Molecular Structure , Staphylococcus aureus/drug effects , Xylariales/metabolism
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