Isolation and Characterization of Sesquiterpenoids from Cassia Buds and Their Antimicrobial Activities

Evaluation of different drying methods on the quality of Cinnamomum cassia barks by analytic hierarchy process method

Cinnamomum cassia Presl is a major food spice as well as traditional herbal medicine with anti-inflammatory, analgesic, and stomachic properties, which must be dried to preserve its quality, but mostly by using traditional, ineffective drying method. In order to find a scientific drying method by evaluating different drying methods that could influence the quality of C. cassia, ten indices were employed to evaluate different drying methods in C. cassia using the Analytic Hierarchy Process (AHP) method though calculating the total scores and ranking the priority. Four quality markers (Q-Markers) (coumarin, cinnamyl alcohol, cinnamaldehyde and o-methoxycinnamaldehyde) were isolated from the samples and analyzed by high performance liquid chromatography (HPLC) method under different drying methods. The results showed that various drying methods had multiple effects on the physicochemical qualities, essential oil content, and Q-Marker contents. Compared with other drying methods, oven-drying of 45 °C (45OD) maintained optimal levels of color and aroma, it also significantly shortened the drying time by 225 h than traditionally shade-drying (SHD) method with the drying rate (48.35 %), and obtained the highest essential oil content (3.05 %) and Q-Marker contents (30.23 mg g-1). Furthermore, the ash content (4.22 %) were satisfied with the stipulation of Chinese pharmacopoeia in 45OD samples. Applying AHP allowed us to identify 45OD as the optimal drying method with the highest total score (9.00), followed by the traditional shade-drying (SHD) method (7.88). The present study is the first report to apply the AHP method for quality evaluation of drying processing in C. cassia. It can provide the theoretical basis for evaluating an excellent method for C. cassia drying processing, as well as the rational use of different drying methods to furtherly develop the high quality C. cassia industry.

Integrated transcriptomics and metabolomics analysis provides insights into aromatic volatiles formation in Cinnamomum cassia bark at different harvesting times

BACKGROUND

Cinnamomum cassia Presl, classified in the Lauraceae family, is widely used as a spice, but also in medicine, cosmetics, and food. Aroma is an important factor affecting the medicinal and flavoring properties of C. cassia, and is mainly determined by volatile organic compounds (VOCs); however, little is known about the composition of aromatic VOCs in C. cassia and their potential molecular regulatory mechanisms. Here, integrated transcriptomic and volatile metabolomic analyses were employed to provide insights into the formation regularity of aromatic VOCs in C. cassia bark at five different harvesting times.

RESULTS

The bark thickness and volatile oil content were significantly increased along with the development of the bark. A total of 724 differentially accumulated volatiles (DAVs) were identified in the bark samples, most of which were terpenoids. Venn analysis of the top 100 VOCs in each period showed that twenty-eight aromatic VOCs were significantly accumulated in different harvesting times. The most abundant VOC, cinnamaldehyde, peaked at 120 months after planting (MAP) and dominated the aroma qualities. Five terpenoids, α-copaene, β-bourbonene, α-cubebene, α-funebrene, and δ-cadinene, that peaked at 240 MAP could also be important in creating C. cassia's characteristic aroma. A list of 43,412 differentially expressed genes (DEGs) involved in the biosynthetic pathways of aromatic VOCs were identified, including phenylpropanoids, mevalonic acid (MVA) and methylerythritol phosphate (MEP). A gene-metabolite regulatory network for terpenoid and phenylpropanoid metabolism was constructed to show the key candidate structural genes and transcription factors involved in the biosynthesis of terpenoids and phenylpropanoids.

CONCLUSIONS

The results of our research revealed the composition and changes of aromatic VOCs in C. cassia bark at different harvesting stages, differentiated the characteristic aroma components of cinnamon, and illuminated the molecular mechanism of aroma formation. These foundational results will provide technical guidance for the quality breeding of C. cassia.

Deciphering the antifungal mechanism and functional components of cinnamomum cassia essential oil against Candida albicans through integration of network-based metabolomics and pharmacology, the greedy algorithm, and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

Fungal pathogens can cause deadly invasive infections and have become a major global public health challenge. There is an urgent need to find new treatment options beyond established antifungal agents, as well as new drug targets that can be used to develop novel antifungal agents. Cinnamomum cassia is a tropical aromatic plant that has a wide range of applications in traditional Chinese medicine, especially in the treatment of bacterial and fungal infections.

AIM OF THE STUDY

The present study aimed to explore the mechanism of action and functional components of Cinnamomum cassia essential oil (CEO) against Candida albicans using an integrated strategy combining network-based metabolomics and pharmacology, the greedy algorithm and molecular docking.

MATERIALS AND METHODS

CEO was extracted using hydrodistillation and its chemical composition was identified by GC-MS. Cluster analysis was performed on the compositions of 19 other CEOs from the published literature, as well as the sample obtained in this study. The damages of C. albicans cells upon treatment with CEO was observed using a scanning electron microscope. The mechanisms of its antifungal effect at a subinhibitory concentration of 0.1 × MIC were determined using microbial metabolomics and network analysis. The functional components were studied using the greedy algorithm and molecular docking.

RESULTS

A total of 69 compounds were identified in the chemical analysis of CEO, which accounted for 90% of the sample. The major compounds were terpenoids (34.04%), aromatic compounds (4.52%), aliphatic compounds (0.9%), and others. Hierarchical cluster analysis of the compositions of 20 essential oils extracted from Cinnamomum cassia grown in different geographical locations showed a wide diversity of chemical composition with four major chemotypes. CEO showed strong antifungal activity and caused destruction of cell membranes in a concentration-dependent way. Metabolic fingerprint analysis identified 29 metabolites associated with lipid metabolism, which were mapped to 23 core targets mainly involved in fatty acid biosynthesis and metabolism. Six antifungal functional components of CEO were identified through network construction, greedy algorithm and molecular docking, including trans-cinnamaldehyde, δ-cadinol, ethylcinnamate, safrole, trans-anethole, and trans-cinnamyl acetate, which showed excellent binding with specific targets of AKR1B1, PPARG, BCHE, CYP19A1, CYP2C19, QPCT, and CYP51A1.

CONCLUSIONS

This study provides a systematic understanding of the antifungal activity of CEO and offers an integrated strategy for deciphering the potential metabolism and material foundation of complex component drugs.

Antibacterial and Antifungal Terpenes from the Medicinal Angiosperms of Asia and the Pacific: Haystacks and Gold Needles

This review identifies terpenes isolated from the medicinal Angiosperms of Asia and the Pacific with antibacterial and/or antifungal activities and analyses their distribution, molecular mass, solubility, and modes of action. All data in this review were compiled from Google Scholar, PubMed, Science Direct, Web of Science, ChemSpider, PubChem, and library searches from 1968 to 2022. About 300 antibacterial and/or antifungal terpenes were identified during this period. Terpenes with a MIC ≤ 2 µg/mL are mostly amphiphilic and active against Gram-positive bacteria, with a molecular mass ranging from about 150 to 550 g/mol, and a polar surface area around 20 Ų. Carvacrol, celastrol, cuminol, dysoxyhainic acid I, ent-1β,14β-diacetoxy-7α-hydroxykaur-16-en-15-one, ergosterol-5,8-endoperoxide, geranylgeraniol, gossypol, 16α-hydroxy-cleroda-3,13 (14)Z-diene-15,16-olide, 7-hydroxycadalene, 17-hydroxyjolkinolide B, (20R)-3β-hydroxy-24,25,26,27-tetranor-5α cycloartan-23,21-olide, mansonone F, (+)-6,6'-methoxygossypol, polygodial, pristimerin, terpinen-4-ol, and α-terpineol are chemical frameworks that could be candidates for the further development of lead antibacterial or antifungal drugs.

Chemical constituents of Rumex dentatus L. and their antimicrobial and anti-inflammatory activities

Antimicrobial bioactivity-guided isolation of the root extract of Rumex dentatus L. resulted in the characterization of nineteen natural products, including three undescribed compounds (rumexs A-C). Rumexs A and B are rare anthraquinone-anthrone dimers consisting of an emodin-10-C-glycoside linked via C-10 to C-7 of a chrysophanol moiety. They differed only in their configuration at C-10; their absolute configurations were determined by NOESY and ECD analysis. LC-HRMS analysis was performed to identify nineteen compounds. Anthraquinone derivatives such as anthraquinone aglycone, oxanthrone C-glycoside, anthraquinone O-glycoside and anthraquinone dimer were found to be the dominant components of R. dentatus. In addition, naphthol, naphthoquinone, chromone, flavonoid, isocoumarin, and lignanamide derivatives were also identified. Chrysophanol and emodin were the most abundant compounds in the crude ethanol extract; their contents were determined by HPLC to be 7.38 and 5.74 mg/g, respectively. The fractions and isolated compounds were tested for their inhibitory activity against Staphylococcus aureus, Candida albicans, and Escherichia coli. Most of them showed inhibitory activity against S. aureus, some fractions and 2-methoxy-6-acetyl-7-methyljuglone exhibited moderate inhibitory activity against C. albicans, and 2-methoxy-6-acetyl-7-methyljuglone had moderate inhibitory effects against E. coli. Emodin exhibited inhibitory activity against NO release in LPS-reduced RAW264.7 cells in a concentration-dependent manner.

Chemical characteristics of the sesquiterpenes and diterpenes from Lauraceae family and their multifaceted health benefits: A review

Lauraceae is a large family with significant economic and medicinal value. Bioactive ingredients from Lauraceae plants have contributed greatly to medicines, food nutrients and fine chemical products. In recent years, quite a few sesquiterpenes and diterpenes with unique structures have been achieved from Lauraceae and their potential benefits are embodied in a wide range of health areas. To our knowledge, there is no review to summarizes these constituents and their biological effects systematically. This current work aims to classify and ascribe the structural types and bioactivities of the identified sesquiterpenes and diterpenes. Herein, a total of 362 sesquiterpenes and 69 diterpenes were comprehensively complied. The various bioactivities could be recognized as cytotoxicity, anti-proliferation and/or anti-apoptosis, anti-inflammation, anti-oxidation, anti-bacterium, etc. This updated data could serve as a catalysis of these sesquiterpenes and diterpenes for the future medical and industrial applications.

Antibacterial and Antifungal Sesquiterpenoids: Chemistry, Resource, and Activity

Infectious diseases caused by bacteria and fungi are threatening human health all over the world. It is an increasingly serious problem that the efficacies of some antibacterial and antifungal agents have been weakened by the drug resistance of some bacteria and fungi, which makes a great need for new antibiotics. Sesquiterpenoids, with abundant structural skeleton types and a wide range of bioactivities, are considered as good candidates to be antibacterial and antifungal agents. In the past decades, many sesquiterpenoids were isolated from plants and fungi that exhibited good antibacterial and antifungal activities. In this review, the names, source, structures, antibacterial and antifungal degrees, and mechanisms of sesquiterpenoids with antibacterial and antifungal activity from 2012 to 2022 are summarized, and the structure-activity relationship of these sesquiterpenoids against bacteria and fungi is also discussed.

Chemical composition and antibacterial activity of 12 medicinal plant ethyl acetate extracts using LC-MS feature-based molecular networking

INTRODUCTION

Widespread use of antibiotics has led to an increase in bacterial multiple drug resistance, thereby searching for natural antimicrobial agents from plants becomes an effective and alternative approach. In the present study, we selected six foodborne bacteria to evaluate the antibacterial activities of 12 medicinal plants ethyl acetate (EA) extracts.

OBJECTIVE

This study aims to search for natural antibiotic substitutes from plant extracts. The antibacterial components were further discussed through chemometric and mass spectroscopic analyses.

METHODOLOGY

Agar well diffusion and the microdilution methods were used to test the antibacterial activity. Total phenolic content (TPC) and total flavonoid content (TFC) were used to judge the active phytochemicals. To further characterise the potential antibacterial components, an ultra-performance liquid chromatography-quadrupole-time of flight-mass spectrometry (UPLC-Q-TOF-MS) coupled with Pearson correlation and feature-based molecular network (FBMN) were proposed.

RESULTS

Most of the plant extracts possessed antibacterial activity against Bacillus subtilis and Salmonella typhi. Toona sinensis shoots and Firmiana simplex barks showed high inhibitory activities against Staphylococcus aureus, Shigella dysenteriae, and Escherichia coli strains with minimum inhibitory concentrations (MICs) of 1.56, 0.78, and 0.39 mg/mL, respectively. Salmonella typhi was highly sensitive to Firmiana simplex barks with an inhibitory diameter up to 21.67 ± 0.95 mm, and MIC at 0.78 mg/mL. Moreover, Toona sinensis shoots and Firmiana simplex barks had the highest TPCs.

CONCLUSION

Our results indicated that Toona sinensis shoots, Koelreuteria paniculate seeds, and Firmiana simplex barks could be supplied as potential sources of antimicrobial agents. Furthermore, 36 potential bioactive compounds were identified mainly as polyphenols, glycosides, and terpenoids.

Highly oxygenated isoryanodane diterpenoids from the leaves of Cinnamomum cassia and their immunomodulatory activities

A total of twelve highly oxygenated isoryanodane (also known as cinncassiol D-type) diterpenoids including nine undescribed ones, named cinnacassins A-I, were isolated from the leaves of Cinnamomum cassia. Their chemical structures were elucidated by extensive spectrometric and spectroscopic techniques including HRESIMS, 1D and 2D NMR, single-crystal X-ray diffraction analysis, calculated ¹³C-NMR DP4+ analysis, and chemical methods. The absolute configuration of cinnacassin A was unambiguously delineated by single-crystal X-ray diffraction analysis. Cinnacassin H represents the first example of 16-O-glucosylated isoryanodane diterpenoid, and cinnacassin I is the first isoryanod-13(18)-ene diterpenoid. The relationship of the configuration C-18 and the chemical shifts of H₂-19 and C-20 in the 19-hydroxy-isoryanodane diterpenoids was discussed, and the 18S-configuration of three known 19-hydroxy-isoryanodane diterpenoids, cinncassiol D₁, 19-O-β-D-glucopyranosyl-cinncassiol D₁, and cinncassiol D₃ was assigned. All the isolated isoryanodane diterpenoids were evaluated for their immunomodulatory effects in vitro, and cinnacassin A and cinncassiol D₁ enhanced the proliferation of Con A-induced murine T cells with enhancement rates ranging from 17.9% to 45.4%, which were more potent than the positive control, thymosin α1. In addition, cinncassiol D₁ significantly promoted the proliferation of LPS-induced murine B cells with an enhancement rate up to 116.1%, two-fold more potent than thymosin α1 at a concentration of 1.5625 μM.

Phenolic Compounds and Bioactivities from Pomegranate (Punica granatum L.) Peels

Pomegranate peels, which are normally processed as the main byproduct of pomegranate juice production, are worthy of being researched and utilized for the aim of economic and environmental benefits. In a phytochemical investigation of the peels of Punica granatum L., 10 phenolic compounds containing a common hexahydroxy diphenol moiety were isolated. Three of them were identified for the first time and named as pomegranatins A-C, and from the other seven known ones, two of them were obtained from pomegranate peels for the first time. Their structures were determined via extensive spectroscopic analysis. Besides, for the sake of preliminarily comprehending their biological activities, in vitro antimicrobial, antioxidant, as well as antitumor assays were detected. In the DPPH antioxidant assay, six compounds presented significant free radical scavenging ability. Two compounds exhibited moderate antimicrobial activities against Candida albicans; one compound could inhibit the proliferation of both C. albicans and Escherichia coli within limits. Four compounds possessed weak antitumor activity toward the Hela cell line without taking into account the bioavailability of ellagitannins. Overall, these results provided further information on the structural diversity of bioactive compounds present in pomegranate peels, as well as on their biological activities.

Structurally Diverse Diterpenoids from the Roots of Salvia deserta Based on Nine Different Skeletal Types

Twenty-four diterpenoids (1-24), classified into nine diverse carbon skeletal types, 8-nor-7(8→14),9(8→7)-di-abeo-abietane (1, 2, and 13), 7(8→14),9(8→7)-di-abeo-abietane (3 and 4), 6-nor-6,7-seco-abietane (5 and 6), 6,7-seco-abietane (7 and 11), 9,10-seco-abietane (8), abietane (9, 10, and 14-21), 11(9→8),20(10→11)-di-abeo-abietane (12), 15(13→12)-abeo-abietane (22 and 23), and 4,5-seco-20(10→5)-abeo-abietane (24), respectively, were isolated from the roots of Salvia deserta. The structures of 10 new diterpenoids, named salviadesertins A-J (1-10), were elucidated by spectroscopic data interpretation, quantum-chemical calculations including calculated ¹³C NMR-DP4+ analysis and electronic circular dichroism as well as X-ray crystallography analysis. The absolute configurations of compounds 1-3, 7, 14, and 22 were defined by single-crystal X-ray diffraction analysis. All the isolated diterpenoids 1-24 were evaluated for their cytotoxicity against five cancer cell lines, and 6-hydroxysalvinolone (14) showed micromolar potencies against MCF-7, A-549, SMMC-7721, and HL-60 cells, whereas the other diterpenoids were inactive (half-maximal inhibitory concentration greater than 10.0 μM).

Chemical Composition of the Hazelnut Kernel (Corylus avellana L.) and Its Anti-inflammatory, Antimicrobial, and Antioxidant Activities

The chemical composition of hazelnut kernels (Corylus avellana L.) and their COX-2 inhibitory, antimicrobial, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical-scavenging activities were investigated. Six previously undescribed indoleacetic acid glycosides, hazelnutins A-F (1-6), and five known compounds (7-11) were isolated from the hazelnut kernels. The structures of compounds 1-6 were successfully identified by high-resolution-electrospray ionization-mass spectrometry and NMR data, and their absolute configurations were established by electron-capture detector spectroscopy analyses in corporation with quantum chemical calculations. Furthermore, the absolute configurations of compounds 7 and 8 were unambiguously confirmed for the first time. Compounds 8-11 were discovered in hazelnut kernels for the first time. Compounds 1-5 inhibited COX-2 expression with inhibition rates ranging from 36.10 to 64.08%. Compounds 3, 4, and 8 could inhibit the proliferation of Candida albicans. Compound 11 exhibited potent antioxidant activity against ABTS and DPPH with IC₅₀ values of 11.22 and 13.21 μmol/L, respectively. Compounds 8 and 10 exhibited moderate antioxidant activity against ABTS.

Lignans and Neolignans with Antioxidant and Human Cancer Cell Proliferation Inhibitory Activities from Cinnamomum bejolghota Confirm Its Functional Food Property

In the aim to evaluate the functional food property of Cinnamomum bejolghota, seven new lignans and neolignans, bejolghotins A-G (1-4 and 9-11), along with 14 known ones (5-8 and 12-21), were isolated and their structures including absolute configurations were elucidated by extensive spectroscopic data and electronic circular dichroism (ECD) analyses. All of the isolates were tested for antioxidant and human cancer cell proliferation inhibitory activities. Twenty compounds showed comparable antioxidant activity to the positive controls, and three significantly inhibited the growth of three cancer cell lines HCT-116, A549, and MDA-MB-231 with IC₅₀ values of 0.78-2.93 μM, which confirmed its health benefits.

Terpenoids and Their Biological Activities from Cinnamomum: A Review

Cinnamomum is a genus of the family Lauraceae, which has been recognized worldwide as an important genus due to its beneficial uses. A great deal of research on its phytochemistry and pharmacological effects has been conducted. It is noteworthy that terpenoids are the characteristic of Cinnamomum due to the peculiar structures and significant biological effects. For a more in-depth study and the better use of Cinnamomum plants in the future, the chemical structures and biological effects of terpenoids obtained from Cinnamomum were summarized in the present study. To date, a total of 181 terpenoids with various skeletons have been isolated from Cinnamomum. These compounds have been demonstrated to play an important role in immunomodulatory, anti-inflammatory, antimicrobial, antioxidant, and anticancer activities. However, studies on the bioactive components from Cinnamomum plants have only focused on a dozen species. Hence, further studies on the potential pharmacological effects need to be conducted in the future.

Traditional uses, phytochemistry and pharmacological activities of the genus Cinnamomum (Lauraceae): A review

Species of Cinnamomum exhibit excellent economic and medicinal value, and have found use in traditional medicine, are consumed as a spice, as well as being cultivated as landscape plants. Investigations into the pharmacological activities of the genus Cinnamomum revealed that it manifested a wide range of pharmacological properties including antimicrobial, antioxidant, anti-inflammatory and analgesic, antitumor, anti-diabetic and anti-obesity, immunoregulation, insecticidal and acaricidal, cardiovascular protective, cytoprotective, as well as neuroprotective properties both in vivo and in vitro. In the past five years, approximately 306 chemical constituents have been separated and identified from the genus Cinnamomum, covering 111 terpenes, 44 phenylpropanoids, 51 lignans, 17 flavonoids, 53 aromatic compounds, 17 aliphatic compounds, four coumarins, two steroids. This article highlights the traditional uses, phytochemistry and pharmacological properties of the few studied taxa of Cinnamomum through searching for the pieces of literature both at home and abroad, which would provide a reference for the pharmaceutical research and clinical application of this genus.

Cyperane-Type and Related (Nor)Sesquiterpenoids from the Root Bark of Acanthopanax gracilistylus and Their Inhibitory Effects on Nitric Oxide Production

An enantiomeric pair of rare cyperane-type sesquiterpenoids, (+)- and (-)-gracilistones C (1a, 1b), together with a novel norsesquiterpenoid, gracilistone D (2), bearing a bicyclic lactone system were isolated from the root bark of Acanthopanax gracilistylus using LC-MS-IT-TOF analyses. The structures and absolute configurations of 1a, 1b, and 2 were elucidated by 1D and 2D NMR spectroscopy, X-ray diffraction, and ECD spectroscopic methods. Intermediate 1b suggests a possible biosynthesis process involving compound 2. The bioassay results showed that compounds 1a, 1b, and 2 exhibited significant inhibitory effects against lipopolysaccharide-induced nitric oxide production in RAW 264.7 cells, with IC₅₀ values of 7.7 ± 0.6, 6.8 ± 1.5, and 2.6 ± 0.4 μM, respectively. Additional docking analyses provided some perspective of this activity in human inducible nitric oxide synthase.

Antimicrobial Terpenoids as a Potential Substitute in Overcoming Antimicrobial Resistance

There was a golden era where everyone thought that microbes can no longer establish threat to humans but the time has come where microbes are proposing strong resistance against the majority of antimicrobials. Over the years, the inappropriate use and easy availability of antimicrobials have made antimicrobial resistance (AMR) to emerge as the world's third leading cause of death. Microorganisms over the time span have acquired resistance through various mechanisms such as efflux pump, transfer through plasmids causing mutation, changing antimicrobial site of action, or modifying the antimicrobial which will lead to become AMR as the main cause of death worldwide by 2030. In order to overcome the emerging resistance against majority of antimicrobials, there is a need to uncover drugs from plants because they have proved to be effective antimicrobials due to the presence of secondary metabolites such as terpenoids. Terpenoids abundant in nature are produced in response to microbial attack have huge potential against various microorganisms through diverse mechanisms such as membrane disruption, anti-quorum sensing, inhibition of protein synthesis and ATP. New approaches like combination therapy of terpenoids and antimicrobials have increased the potency of treatment against various multidrug resistant microorganisms by showing synergism to each other.

Spirodesertols A and B, two highly modified spirocyclic diterpenoids with an unprecedented 6-isopropyl-3H-spiro[benzofuran-2,1′-cyclohexane] motif from Salvia deserta

Two highly modified spirocyclic diterpenoids with an unprecedented 6-isopropyl-3H-spiro[benzofuran-2,1′-cyclohexane] motif and four new icetexane diterpenoids were isolated from Salvia deserta. 1 showed more potent cytotoxicity than cis-platin.

Cassiabudanols A and B, Immunostimulative Diterpenoids with a Cassiabudane Carbon Skeleton Featuring a 3-Oxatetracyclo[6.6.1.02,6.010,14]pentadecane Scaffold from Cassia Buds

Two novel diterpenoids, cassiabudanols A (1) and B (2), were isolated from cassia buds. Their structures were determined by comprehensive spectroscopic analysis and single-crystal X-ray diffraction. Compounds 1 and 2 possess an unprecedented 11,14- cyclo-8,14:12,13-di- seco-isoryanodane (cassiabudane) carbon skeleton featuring a unique 3-oxatetracyclo[6.6.1.0^2,6.0^10,14]pentadecane bridged system, and their biosynthetic pathways are proposed. Compounds 1 and 2 exhibited significant immunostimulative activity, and the mode of action of 2 involves upregulating CD4⁺ and CD8⁺ T cells and downregulating Tregs.

Synthesis of Amphiphilic Copolymers Containing Ciprofloxacin and Amine Groups and Their Antimicrobial Performances As Revealed by Confocal Laser-Scanning Microscopy and Atomic-Force Microscopy

Two series of amphiphilic antimicrobial copolymers containing ciprofloxacin (CPF) and amine functional groups have been synthesized via free-radical copolymerization. The chemical structures of the different amine groups and the copolymer compositions have been systematically varied to study how the structure of the copolymer exerts an influence on the antibacterial activity. The viability of Escherichia coli in the presence of antimicrobial copolymers was observed by confocal laser-scanning microscopy (CLSM). CLSM as well as atomic-force microscopy (AFM) were applied to visualize changes in morphology of bacteria treated with antimicrobial copolymers and elucidate the antimicrobial mechanism of the antimicrobial copolymers. Morphological changes of bacteria observed via AFM and CLSM demonstrated that the antibacterial mechanism was due to the disruption of the bacterial membrane. The destruction of the cell membrane was also confirmed by the leakage of intracellular components, which had a strong absorbance at 260 nm. The inhibitory process was monitored by UV absorption dynamically.

Cytochalasans Produced by the Coculture of Aspergillus flavipes and Chaetomium globosum

The cocultivation of Aspergillus flavipes and Chaetomium globosum, rich sources of cytochalasans, on solid rice medium, resulted in the production of 13 new, highly oxygenated cytochalasans, aspochalasinols A-D (1-4) and oxichaetoglobosins A-I (5-13), as well as seven known compounds (14-20). Of these compounds, 13 is a novel cytochalasan with an unexpected 2-norindole group. The isolated compounds were characterized by NMR spectroscopy, single-crystal X-ray crystallography, and ECD experiments. Compounds 1-4 represent the first examples of Asp-type cytochalasans with C-12 hydroxy groups, which may be a result of the coculture, as hydroxylated Me-12 groups are frequently found in Chae-type cytochalasans from C. globosum. In addition, 5-10 are unusual cytochalasans with an oxygenated C-10. Interestingly, 13 is the first example of a naturally occurring cytochalasan possessing a uniquely degraded indole ring that is derived from chaetoglobosin W, with 11 and 12 both serving as its biosynthetic intermediates. In the coculture of A. flavipes and C. globosum, most of these cytochalasans are more functionalized than normal cytochalasans, and the underlying causes may attract substantial attention from synthetic biologists. The cytotoxicities against five human cancer cell lines (SW480, HL-60, A549, MCF-7, and SMMC-7721) and the immunomodulatory activities of these new compounds were evaluated in vitro.

Volatiles from Cinnamomum cassia buds

While the chemical composition of leaf and stem bark essential oils of the Chinese cinnamon, Cinnamomum cassia (L.) J. Presl, has been well investigated, little is known about the volatilom of its buds, which appeared recently on German markets. Soxhlet extracts of the commercial samples were prepared, fractionated using silica gel and characterised by gas chromatography-flame ionisation detector (GC-FID) for semi-quantification, by gas chromatography-mass spectrometry (GC-MS) for identification and by GC-FID/olfactometry for sensory evaluation. Cinnamaldehyde was the most abundant compound with concentrations up to 40 mg/g sample. In total, 36 compounds were identified and 30 were semi-quantified. The extracts contained mostly phenylpropanoids, mono- and sesquiterpene hydrocarbons and oxygenated derivatives. Because of the high abundance of cinnamaldehyde, the aldehyde fraction was removed from the extracts by adding hydrogen sulphite to improve both the detection of trace compounds and column chromatography. The aldehyde fraction was analysed by GC-MS separately. The highest flavour dilution factor of 316 was calculated for cinnamaldehyde. Other main sensory contributors were 2-phenylethanol and cinnamyl alcohol. This report provides the first GC-olfactometry data of a plant part of a Cinnamomum species. The strongly lignified C. cassia buds combine a high abundance of cinnamaldehyde with comparably low coumarin concentrations (<0.48 mg/g), and provide a large cinnamaldehyde depot for slow release applications.

New Sesquiterpenoids from Eugenia jambolana Seeds and Their Anti-microbial Activities

Twenty four sesquiterpenoids, 1-24, including 11 new sesquiterpenoids, jambolanins A-K, and two new norsesquiterpenoids, jambolanes A and B, along with six known triterpenoids, were isolated from the seeds of Eugenia jambolana fruit. Their structures were elucidated on the basis of NMR and MS spectrometry data analysis. Among the isolates, compound 13 possessed a rare 6,7-seco-guaiene skeleton, and compounds 14 and 15 were norsesquiterpenoids containing a spiro[4.4]nonane skeleton. Antimicrobial assay evaluation revealed that sesquiterpenoids, 4, 5/6, 17, 19, 21, 23, and 24 inhibited the growth of the Gram-positive bacterium, Staphylococcus aureus. The current study advances scientific knowledge of E. jambolana phytochemicals and suggests that its sesquiterpenoids may contribute, in part, to the anti-infective effects attributed to the edible fruit of this plant.