Antimicrobial and antileishmanial activities of hypocrellins A and B

Susceptibility of Leishmania to novel pentavalent organometallics: Investigating impact on DNA and membrane integrity in antimony(III)-sensitive and -resistant strains

The aim the present study was to investigate the impact of novel pentavalent organobismuth and organoantimony complexes on membrane integrity and their interaction with DNA, activity against Sb(III)-sensitive and -resistant Leishmania strains and toxicity in mammalian peritoneal macrophages. Ph3M(L)2 type complexes were synthesized, where M = Sb(V) or Bi(V) and L = deprotonated 3-(dimethylamino)benzoic acid or 2-acetylbenzoic acid. Both organobismuth(V) and organoantimony(V) complexes exhibited efficacy at micromolar concentrations against Leishmania amazonensis and L. infantum but only the later ones demonstrated biocompatibility. Ph3Sb(L1)2 and Ph3Bi(L1)2 demonstrated distinct susceptibility profiles compared to inorganic Sb(III)-resistant strains of MRPA-overexpressing L. amazonensis and AQP1-mutated L. guyanensis. These complexes were able to permeate the cell membrane and interact with the Leishmania DNA, suggesting that this effect may contribute to the parasite growth inhibition via apoptosis. Taken altogether, our data substantiate the notion of a distinct mechanism of uptake pathway and action in Leishmania for these organometallic complexes, distinguishing them from the conventional inorganic antimonial drugs.

Biotechnological production and potential applications of hypocrellins

Hypocrellins (HYPs), a kind of natural perylenequinones (PQs) with an oxidized pentacyclic core, are important natural compounds initially extracted from the stromata of Hypocrella bambusae and Shiraia bambusicola. They have been widely concerned for their use as anti-microbial, anti-cancers, and anti-viral photodynamic therapy agents in recent years. Considering the restrictions of natural stromal resources, submerged fermentation with Shiraia spp. has been viewed as a promising alternative biotechnology for HYP production, and great efforts have been made to improve HYP production over the past decade. This article reviews recent publications about the mycelium fermentation production of HYPs, and their bioactivities and potential applications, and especially summarizes the progresses toward manipulation of fermentation conditions. Also, their chemical structure and analytic methods are outlined. Herein, it is worth mentioning that the gene arrangement in HYP gene cluster is revised; previous unknown genes in HYP and CTB gene clusters with correct function annotation are deciphered; the homologous sequences of HYP, CTB, and elc are systematically aligned, and especially the biosynthetic pathway of HYPs is full-scale proposed. KEY POINTS: • The mycelial fermentation process and metabolic regulation of hypocrellins are reviewed. • The bioactivities and potential applications of hypocrellins are summarized. • The biosynthesis pathway and regulatory mechanisms of hypocrellins are outlined.

Antimicrobial photodynamic inactivation as an alternative approach to inhibit the growth of Cronobacter sakazakii by fine-tuning the activity of CpxRA two-component system

Cronobacter sakazakii is an opportunistic foodborne pathogen primarily found in powdered infant formula (PIF). To date, it remains challenging to control the growth of this ubiquitous bacterium. Herein, antimicrobial photodynamic inactivation (aPDI) was first employed to inactivate C. sakazakii. Through 460 nm light irradiation coupled with hypocrellin B, the survival rate of C. sakazakii was diminished by 3~4 log. The photokilling effect was mediated by the attenuated membrane integrity, as evidenced by PI staining. Besides, scanning electron microscopy showed the deformed and aggregated cell cluster, and intracellular ROS was augmented by 2~3 folds when light doses increase. In addition to planktonic cells, the biofilm formation of C. sakazakii was also affected, showing an OD_590nm decline from 0.85 to 0.25. In terms of molecular aspects, a two-component system called CpxRA, along with their target genes, was deregulated during illumination. Using the knock-out strain of ΔCpxA, the bacterial viability was reduced by 2 log under aPDI, a wider gap than the wildtype strain. Based on the promoted expression of CpxR and OmpC, aPDI is likely to play its part through attenuating the function of CpxRA-OmpC pathway. Finally, the aPDI system was applied to PIF, and C. sakazakii was inactivated under various desiccated or heated storage conditions. Collectively, aPDI serves as an alternative approach to decontaminate C. sakazakii, providing a new strategy to reduce the health risks caused by this prevalent foodborne pathogen.

Advances and perspectives on perylenequinone biosynthesis

Under illumination, the fungal secondary metabolites, perylenequinones (PQs) react with molecular oxygen to generate reactive oxygen species (ROS), which, in excess can damage cellular macromolecules and trigger apoptosis. Based on this property, PQs have been widely used as photosensitizers and applied in pharmaceuticals, which has stimulated research into the discovery of new PQs and the elucidation of their biosynthetic pathways. The PQs-associated literature covering from April 1967 to September 2022 is reviewed in three sections: (1) the sources, structural diversity, and biological activities of microbial PQs; (2) elucidation of PQ biosynthetic pathways, associated genes, and mechanisms of regulation; and (3) advances in pathway engineering and future potential strategies to modify cellular metabolism and improve PQ production.

Rapid Degradation of Rhodamine B through Visible-Photocatalytic Advanced Oxidation Using Self-Degradable Natural Perylene Quinone Derivatives-Hypocrellins

Hypocrellins (HYPs) are natural perylene quinone derivatives from Ascomycota fungi. Based on the excellent photosensitization properties of HYPs, this work proposed a photocatalytic advanced oxidation process (PAOP) that uses HYPs to degrade rhodamine B (RhB) as a model organic pollutant. A synergistic activity of HYPs and H2O2 (0.18 mM of HYPs, 0.33% w/v of H2O2) was suggested, resulting in a yield of 82.4% for RhB degradation after 60 min under visible light irradiation at 470−475 nm. The principle of pseudo-first-order kinetics was used to describe the decomposition reaction with a calculated constant (k) of 0.02899 min−1 (R2 = 0.983). Light-induced self-degradation of HYPs could be activated under alkaline (pH > 7) conditions, promising HYPs as an advanced property to alleviate the current dilemma of secondary pollution by synthetic photocatalysts in the remediation of emerging organic pollutants.

Temperature-responsive regulation of the fermentation of hypocrellin A by Shiraia bambusicola (GDMCC 60438)

BACKGROUND

Hypocrellin A (HA) is a perylene quinone pigment with high medicinal value that is produced by Shiraia bambusicola Henn. (S. bambusicola) and Hypocrella bambusae (Berk. & Broome) Sacc. (Ascomycetes) with great potential in clinical photodynamic therapy. Submerged cultivation of S. bambusicola is a popular technique for HA production. However, there is not much research on how temperature changes lead to differential yields of HA production.

RESULTS

The temperature regulation of submerged fermentation is an efficient approach to promote HA productivity. After a 32 °C fermentation, the HA content in the mycelia S. bambusicola (GDMCC 60438) was increased by more than three- and fivefold when compared to that at 28 °C and 26 °C, respectively. RNA sequencing (RNA-seq) analysis showed that the regulation of the expression of transcription factors and genes essential for HA biosynthesis could be induced by high temperature. Among the 496 differentially expressed genes (DEGs) explicitly expressed at 32 °C, the hub genes MH01c06g0046321 and MH01c11g0073001 in the coexpression network may affect HA biosynthesis and cytoarchitecture, respectively. Moreover, five genes, i.e., MH01c01g0006641, MH01c03g0017691, MH01c04g0029531, MH01c04g0030701 and MH01c22g0111101, potentially related to HA synthesis also exhibited significantly higher expression levels. Morphological observation showed that the autolysis inside the mycelial pellets tightly composted intertwined mycelia without apparent holes.

CONCLUSIONS

The obtained results provide an effective strategy in the submerged fermentation of S. bambusicola for improved HA production and reveal an alternative regulatory network responsive to the biosynthesis metabolism of HA in response to environmental signals.

The promise of low-intensity ultrasound: A review on sonosensitizers and sonocatalysts by ultrasonic activation for bacterial killing

Antimicrobial resistance has become one of the main public health issues in modern society. Ultrasonicantimicrobial treatment (UAT) is expected to solve the problem of antimicrobial resistance since ultrasonic treatment does not cause drug resistance during inactivation. However, the ultrasonic application is hindered due to the high energy cost. To cast more lights on the ultrasound in tandem with catalysts as a superior strategy for bacterial inactivation, the present review focuses on the UAT with the assistant of continuous development of organic sonosensitizer and inorganic sonocatalyst. With the application of these nanomaterials, the ultrasonic parameters changed from low-frequency and high-power ultrasound to high-frequency and low-power ultrasound. The review also presents the composition of sonosensitizers/sonocatalysts including organic and inorganic nanoparticles and discusses the ultrasonic activation mechanisms triggered by these catalysts. Based on the synergistic effect of ultrasound and catalysts, we discuss the importance of extracellular oxidation and intracellular oxidation in the process of bacterial inactivation. Overall, UAT combined with catalysts appears to be an effective treatment strategy that can be successfully applied in the field of medicine, environmental treatment, and food industry.

Anti-leishmanial compounds from microbial metabolites: a promising source

Leishmania is a complex disease caused by the protozoan parasites and transmitted by female phlebotomine sandfly. The disease affects some of the poorest people on earth with an estimated 700,000 to 1 million new cases annually. The current treatment for leishmaniasis is toxic, long, and limited, in view of the high resistance rate presented by the parasite, necessitating new perspectives for treatment. The discovery of new compounds with different targets can be a hope to make the treatment more efficient. Microbial metabolites and their structural analogues with enormous scaffold diversity and structural complexity have historically played a key role in drug discovery. We found thirty-nine research articles published between 1999 and 2021 in the scientific database (PubMed, Science Direct) describing microbes and their metabolites with activity against leishmanial parasites which is the focus of this review. KEY POINTS: • Leishmania affects the poorest regions of the globe • Current treatments for leishmaniasis are toxic and of limited efficacy • Microbial metabolites are potential sources of antileishmania drugs.

Phylogenetic Position of Shiraia-Like Endophytes on Bamboos and the Diverse Biosynthesis of Hypocrellin and Hypocrellin Derivatives

The main active ingredients of the fruiting bodies of Shiraia bambusicola and Rubroshiraia bambusae are Hypocrellins, belonging perylenequinones with potential photodynamic activity against cancer and microbial diseases. However, the strains of S. bambusicola and R. bambusae do not produce hypocrellins in culture, so resource exploitation of natural products was seriously restricted. In this study, a series of novel Shiraia-like fungal endophyte strains, with varying sporulation ability and synthesizing diverse secondary metabolites, was isolated from different bamboos. Based on phylogenetic analyses and morphological characteristics of the endophytes, Pseudoshiraia conidialis gen. et sp. nov. is proposed. The secondary metabolites of different fruiting bodies and strains have been comprehensively analyzed for the first time, finding that the endophytic strains are shown not only to produce hypocrellins, but also other perylenequinonoid compounds. It was noteworthy that the highest yield of total perylenequinone production and hypocrellin A appeared in P. conidialis CNUCC 1353PR (1410.13 mg/L), which was significantly higher than any other wild type P. conidialis strains in published reports. In view of these results, the identification of Shiraia-like endophytes not only confirm the phylogenetic status of similar strains, but will further assist in developing the production of valuable natural products.

FeIII, CuII and ZnII Complexes of the Rigid 9-Oxido-phenalenone Ligand-Spectroscopy, Electrochemistry, and Cytotoxic Properties

The three complexes [Fe(opo)3], [Cu(opo)2], and [Zn(opo)2] containing the non-innocent anionic ligand opo- (opo- = 9-oxido-phenalenone, Hopo = 9-hydroxyphenalonone) were synthesised from the corresponding acetylacetonates. [Zn(opo)2] was characterised using 1H nuclear magnetic resonance (NMR) spectroscopy, the paramagnetic [Fe(opo)3] and [Cu(opo)2] by electron paramagnetic resonance (EPR) spectroscopy. While the EPR spectra of [Cu(opo)2] and [Cu(acac)2] in dimethylformamide (DMF) solution are very similar, a rather narrow spectrum was observed for [Fe(opo)3] in tetrahydrofuran (THF) solution in contrast to the very broad spectrum of [Fe(acac)3] in THF (Hacac = acetylacetone, 2,4-pentanedione; acac- = acetylacetonate). The narrow, completely isotropic signal of [Fe(opo)3] disagrees with a metal-centred S = 5/2 spin system that is observed in the solid state. We assume spin-delocalisation to the opo ligand in the sense of an opo- to FeIII electron transfer. All compounds show several electrochemical opo-centred reduction waves in the range of -1 to -3 V vs. the ferrocene/ferrocenium couple. However, for CuII and FeIII the very first one-electron reductions are metal-centred. Electronic absorption in the UV to vis range are due to π-π* transitions in the opo core, giving Hopo and [Zn(opo)2] a yellow to orange colour. The structured bands ranging from 400 to 500 for all compounds are assigned to the lowest energy π-π* transitions. They show markedly higher intensities and slight shifts for the CuII (brown) and FeIII (red) complexes and we assume admixing metal contributions (MLCT for CuII, LMCT for FeIII). For both complexes long-wavelength absorptions assignable to d-d transitions were detected. Detailed spectroelectrochemical experiments confirm both the electrochemical and the optical assignments. Hopo and the complexes [Cu(opo)2], [Zn(opo)2], and [Fe(opo)3] show antiproliferative activities against HT-29 (colon cancer) and MCF-7 (breast cancer) cell lines in the range of a few µM, comparable to cisplatin under the same conditions.

Microorganisms as a Potential Source of Molecules to Control Trypanosomatid Diseases

Trypanosomatids are the causative agents of leishmaniasis and trypanosomiasis, which affect about 20 million people in the world’s poorest countries, leading to 95,000 deaths per year. They are often associated with malnutrition, weak immune systems, low quality housing, and population migration. They are generally recognized as neglected tropical diseases. New drugs against these parasitic protozoa are urgently needed to counteract drug resistance, toxicity, and the high cost of commercially available drugs. Microbial bioprospecting for new molecules may play a crucial role in developing a new generation of antiparasitic drugs. This article reviews the current state of the available literature on chemically defined metabolites of microbial origin that have demonstrated antitrypanosomatid activity. In this review, bacterial and fungal metabolites are presented; they originate from a range of microorganisms, including cyanobacteria, heterotrophic bacteria, and filamentous fungi. We hope to provide a useful overview for future research to identify hits that may become the lead compounds needed to accelerate the discovery of new drugs against trypanosomatids.

Axial Chiral Binaphthoquinone and Perylenequinones from the Stromata of Hypocrella bambusae Are SARS-CoV-2 Entry Inhibitors

A new axial chiral binaphtoquinone, hypocrellone (1), and a new perylenequinone, hypomycin F (2), were isolated from the stromata of Hypocrella bambusae, together with five known compounds, 3-7. The structures of 1 and 2 were assigned by spectroscopic and HRESIMS data analyses. The axial chirality of 1 was determined by electronic circular dichroism data analysis, and the absolute configurations of 2 and 3 were determined by X-ray crystallography. The axial chirality of 7 was determined by UV-induced photooxidation from 4. Compounds 1, 4, and 5 showed inhibitory activity against pseudotyped SARS-CoV-2 infection in 293T-ACE2 cells with IC₅₀ values of 0.17, 0.038, and 0.12 μM. Compounds 4 and 5 were also active against live SARS-CoV-2 infection with EC₅₀ values of 0.22 and 0.21 μM, respectively. Further cell-cell fusion assays, surface plasmon resonance assays, and molecular docking studies revealed that 4 and 5 could bind with the receptor-binding domain of SARS-CoV-2 S protein to prevent its interaction with human angiotensin-converting enzyme II receptor. Our results revealed that 4 and 5 are potential SARS-CoV-2 entry inhibitors.

Anti-leishmanial and anti-trypanosomal natural products from endophytes

Leishmania spp. and Trypanosoma cruzi are parasites belonging to the Trypanosomatidae family and the causative agents for two very important neglected tropical diseases (NTDs), namely leishmaniasis and trypanosomiasis, respectively. Together, they affect millions of people worldwide and the number of cases is constantly rising; thus, further effort on identifying and developing non-toxic, affordable and effective new drug is urgently needed to overcome this alarming situation. Exploring natural products from fungal and bacterial origin remains hitherto a valuable approach to find new hits and candidates for the development of new drugs against these protozoal human infections. Endophytes, which are microorganisms (fungal and bacterial) inhabiting plant tissues, represent a promising source, as they hold potential to produce a high number of distinct chemical scaffolds. These structurally diverse natural products have previously been successfully tested against a wide range of pathogenic microorganisms. The present review provides an update of endophytic compounds exerting anti-trypanosomal and anti-leishmanial effects and their predicted pharmacokinetic properties.

Enhanced Production and Anticancer Properties of Photoactivated Perylenequinones

Hypocrellins and hypomycins are naturally occurring fungal perylenequinones with potential photodynamic activity against cancer and microbial diseases. This project pursued three lines of research. First, the production of perylenequinones was enhanced by investigating the effect of culture medium and light exposure on their biosynthesis. Solid-fermentation cultures on rice medium allowed for enhanced production of hypocrellins as compared to Cheerios or oatmeal medium. Alternatively, increased production of hypomycins, which are structurally related to the hypocrellins, was observed on oatmeal medium. In both cases, light exposure was an essential factor for the enhanced biosynthesis. In addition, this led to the discovery of two new perylenequinones, ent-shiraiachrome A (5) and hypomycin E (8), which were elucidated based on spectroscopic data. Finally, the photocytotoxic effects of both classes of compounds were evaluated against human skin melanoma, with EC50 values at nanomolar levels for hypocrellins and micromolar levels for hypomycins. In contrast, both classes of compounds showed reduced dark toxicity (EC50 values >100 μM), demonstrating promising phototherapeutic indices.

Phytochemical and pharmacological appraisal of the aerial parts of Lotus corniculatus L. growing in Egypt

Lotus corniculatus L. (Fabaceae) is widely grown in Egypt. It has a great history of folkloric medicinal uses. All fractions of aerial parts of L. corniculatus L. showed significant antioxidant and immunostimulant activities and could strongly induce lymphoproliferation. However, the light petrol fraction had antifungal activity against C. neoformans with IC₅₀ value (<8 µg/mL) and exhibited strongest in-vitro antiprotozoal activity against protozoan parasites belonging to the genera Trypanosoma with IC₅₀ value (0.98 µg/mL) and Plasmodium (with 100% inhibition using a sample concentration of 15866.7 ng/mL). This is the first study of the immunostimulant and antiprotozoal activities of genus Lotus. By this approach, it was possible to isolate eight compounds (-)-7,2'-dihydroxy-4'-methoxyisoflavan (vestitol) (1), kaempferol (2), kaempferol 3-O-α-L-rhamnoside (afzelin) (3), kaempferol 3, 7-O-α-L-dirhamnoside (kaempferitin) (4), kaempferol-3-O-[β-D-xylopyranosyl (1″'→2″)-β-D-galactopyranoside] (5), 3-O-[β-D-glucuronopyranosyl] soyasapogenol B (6), kaempferol-3-O-[β-D-xylopyranosyl (1″'→2″)-β-D-galactopyranoside]-7-O-α-L-rhamnopyranoside (7) and 3-O-[α-L-rhamnopyranosyl (1″'→2″)-β-D-galactopyranosyl-(1″→2')-β-D-glucuronopyranosyl] soyasapogenol B (soyasaponin І) (8).

Antifungal activity of hypocrellin compounds and their synergistic effects with antimicrobial agents against Candida albicans

Candida albicans is a common human fungal pathogen. The previous study revealed that quinone compounds showed antimicrobial activity against C. albicans by inhibiting cell growth. However, it was unclear whether quinones have other antifungal effects against C. albicans in addition to fungicidal effects. In this study, we assessed the inhibitory activity of a total of 25 quinone compounds against C. albicans morphological transition, which is essential for the pathogenicity of C. albicans. Several quinones exhibited strong inhibition of mycelium formation by C. albicans SC5314. Three leading compounds, namely hypocrellins A, B and C, also exhibited marked attenuation of C. albicans SC5314 virulence in both human cell lines and mouse infection models. These three compounds significantly suppressed the proliferation of C. albicans SC5314 cells in a mouse mucosal infection model. Intriguingly, hypocrellins not only attenuated the cytotoxicity of a nystatin-resistant C. albicans strain but also showed excellent synergistic effects with antifungal agents against both wild-type C. albicans SC5314 and the drug-resistant mutant strains. In addition, hypocrellins A, B and C interfered with the biological functions and virulence of various clinical Candida species, suggesting the promising potential of these compounds for development as new therapeutic agents against infections caused by Candida pathogens.

Inhibition of ROS-NF-κB-dependent autophagy enhances Hypocrellin A united LED red light-induced apoptosis in squamous carcinoma A431 cells

Cutaneous squamous cell carcinoma (cSCC) is a type of malignant skin tumor derived from epidermal Malpighian cells. Photodynamic therapy is regarded as a crucial method in oncology. Hypocrellin A (HA), an efficient natural photosensitizer, has been reported to exert excellent light induced antiviral, antimicrobial and anticancer activity through mediating multiple signaling pathways. The purpose of the present study is to examine the effects of HA united red light irradiation on human squamous carcinoma A431 cells and further reveal the underlying regulatory mechanisms. The results showed that synergistic treatment of HA and red light irradiation inhibited cell proliferation and induced cell apoptosis and autophagy. Moreover, HA united red light irradiation caused a significant accumulation of reactive oxygen species (ROS), and induced the activation of c-Jun NH 2 terminal kinases (JNKs) which was inhibited by the antioxidant N-Acetyl-cysteine (NAC). Furthermore, HA united red light irradiation activated the nuclear factor-kappa B (NF-κB) pathway, and inhibition of NF-κB activity exacerbated HA united red light irradiation-induced apoptosis but suppressed cell autophagy. In addition, the inhibition of autophagy promoted HA united red light irradiation-induced apoptosis and facilitated the NF-κB activity. Over all, our results revealed that HA united red light irradiation could inhibit A431 cell proliferation by inducing apoptosis and autophagy via the activation of the ROS mediated JNK and NF-κB pathways, providing prospective for HA as a potential therapeutic for the treatment of cSCC.

Phytochemical, in-vitro biological and chemo-preventive profiling of Arisaema jacquemontii Blume tuber extracts

Background

Arisaema jacquemontii is traditionally used in treatment of different diseases. In this study, phytochemical, in vitro biological and chemo-preventive screening of A. jacquemontii was carried out to explore its pharmacological potential.

Methods

The dried tuber of A. jacquemontii was extracted in 11 organic solvent mixture of different polarity. The extracts were screened for phytochemical assays (phenolics and flavonoids), antioxidants potential (free radical scavenging activity, total antioxidant activity, reducing power), biological activities (antibacterial, antifungal, cytotoxic, antileishmanial, protein kinase inhibition), and chemopreventive activities using different cell lines through standard protocols.

Results

Significant amount phenolic contents were determined in EtOH and MeOH extracts (210.3 ± 3.05 and 193.2 ± 3.15 μg GAE/mg, respectively). Maximum flavonoid content was determined in MeOH extract (22.4 ± 4.04 μg QE/mg). Noteworthy, DPPH scavenging activity was also recorded for MeOH extract (87.66%) followed by MeOH+EtOAc extract (85.11%). Considerable antioxidant capacity (7.8 ± 0.12 μg AAE/mg) and reducing power (3.1 ± 0.15 μg AAE/mg) was observed in extract of MeOH. The LC₅₀ against brine shrimp and leishmanial parasite was found 9.01 and 12.87 μg/mL for n-Hex and CHCl₃ extracts, respectively. The highest zone of inhibition against Streptomyces hyphae formation (12.5 ± 1.77 mm) by n-Hex extract. Growth zone of inhibition 13.8 ± 1.08 mm was recorded for EtOAc and MeOH extracts, respectively against Micrococcus luteus while 10.0 ± 0.11 mm for MeOH extract against Aspergillus flavus. In-vitro cytotoxic assay showed that n-Hex extract had higher cytotoxicity against DU-145 prostate cancer and HL-60 cancer cell lines. NF-kB and MTP potential showed 34.01 and 44.87 μg/mL for n-Hex and CHCl₃ extracts, respectively in chemo-preventive potential.

Conclusion

The study concludes that Arisaema jacquemontii bears significant phytochemical activity and pharmacological activities, this plant can be further explored for isolation of active component against a number of aliments.

Photodynamic Antifungal Activity of Hypocrellin A Against Candida albicans

Many studies have reported that hypocrellin A (HA) exhibits effective antimicrobial activities with proper irradiation. However, its antifungal activity and the involved mechanism have not been fully defined. In this study, HA-mediated cytotoxicity in Candida albicans cells was evaluated after antimicrobial photodynamic therapy (aPDT). The results showed that 1.0 μg/ml HA significantly decreased the survival rate of C. albicans cells with light illumination. Moreover, the ROS levels were also remarkably elevated by HA. Further study found that HA combined with illumination led to cell membrane potential depolarization and cell membrane integrity damage. To investigate the form of cell death, a series of apoptosis-related parameters, including mitochondrial transmembrane potential, metacaspase activity, DNA fragmentation, nuclear condensation, and cytosolic and mitochondrial calcium, were analyzed. Data showed that all the above mentioned apoptosis hallmarks were affected after treatment with HA, indicating that HA induced C. albicans cell apoptosis. Finally, HA-mediated aPDT was demonstrated to be low-toxic and effective in treating cutaneous C. albicans infections. This study highlights the antifungal effect and mechanism of HA-mediated aPDT against C. albicans and provides a promising photodynamic antifungal candidate for C. albicans skin infections.

In vitro photodynamic inactivation effects of hypocrellin B on azole-sensitive and resistant Candida albicans

BACKGROUND AND AIM

The extensive use of antifungal drugs has led to resistance from Candida albicans. The search for alternative treatment against drug-resistant C. albicans is highly desirable. Antimicrobial photodynamic therapy (aPDT) is an emerging and promising approach for treating localized and superficial C. albicans infections. The aim of this study was to investigate the photodynamic inactivation (PDI) effects of hypocrellin B (HB) on azole-sensitive and resistant C. albicans in vitro.

METHODS

The PDI efficacies of HB on standard C. albicans strain (ATCC 10231), azole-sensitive clinical isolate of C. albicans, and azole-resistant clinical isolate of C. albicans were assessed. The uptake of HB in C. albicans cells was investigated by confocal laser scanning microscopy (CLSM). The PDI effects on cellular structure and surface characteristics were investigated by transmission electron microscopy (TEM) and scanning electron microscopy (SEM).

RESULTS

HB exhibited no significant dark toxicity, but inactivated the azole-sensitive and resistant C. albicans in a light-dose and PS concentration-dependent manner. CLSM images indicated that PDI treated C. albicans cells showed stronger fluorescence compared to untreated cells. TEM images suggested that significant damage to the cell wall, membrane, and cytoplasm were induced by HB-mediated PDI. SEM analysis revealed that the surface of C. albicans cells became twisted and ruptured after PDI treatment.

CONCLUSIONS

Azole-sensitive and resistant C. albicans could be effectively inactivated by HB in the presence of light, and HB-mediated aPDT shows promise as an antifungal treatment for C. albicans.

Enhanced Production of Hypocrellin A in Submerged Cultures of Shiraia bambusicola by Red Light

Hypocrellin A (HA), a promising photosensitizer for anticancer photodynamic therapy (PDT), is a fungal perylenequinone pigment from the fruiting body of Shiraia bambusicola, a traditional Chinese medicine for treating skin diseases. The mycelial cultures are becoming a biotechnological alternative for HA production. In this study, light of different wavelengths was investigated to develop an effective eliciting strategy for HA production in the cultures. Under red LED light (627 nm) at 200 lux, the maximum HA production (175.53 mg L^-1 ) in mycelium cultures was reached after 8 days, about 3.82-fold of the dark control. Red light not only promoted HA biosynthesis in mycelia (intracellular HA), but also stimulated HA secretion into the medium (extracellular HA). We found 14 of 310 transcripts differentially expressed under red light treatment were possible candidate genes for HA biosynthetic pathway. Gene ontology (GO) analysis revealed that red light treatment could change the gene expressions responsible for HA biosynthesis and the transmembrane activity, suggesting both intracellular HA and its secretion could contribute to the enhancement of total HA production in the cultures. The results provided new insights of red light elicitation and effective strategy for HA production in mycelium cultures.

Evaluation of antioxidant, antimicrobial and cytotoxic potential in Artemisia vulgaris L

Artemisia vulgaris L. (Mugwort or Afsantin) has been used to treat various diseases since ancient times by the inhabitants of Himalayan region-Pakistan. Methanolic fractions (HA1-HA9) obtained from the aerial parts of A. vulgaris were evaluated for their antioxidant, antimicrobial and brine shrimp cytotoxic activities. Fraction HA8 showed substantial phenolics content with value of 26.29±1.4μgEQ/mg and DPPH scavenging (82.84±3.01%). Conversely, total flavonoids content of 7.32±0.07μgEQ/mg was determined in HA1 fraction. Fraction HA1 also showed significant cytotoxic effect with the value LD50 of 144.94μg/mL. Fractions HA7 and HA9 depicted maximum total antioxidant activity and ferric ion reduction (96.25±3.29 and AAE/mg and 176.91±8, respectively). All fractions showed encouraging results against bacterial strains Bordetella bronchiseptica and Micrococcus luteus, while HA2 fraction showed the highest percentage inhibition Mucor species with zone of inhibition of 13.25±0.35mm. A total of 7 fractions showed significant antileishmanial activity with survival percentage ranging 0.00 to 19. To sum up, results of the current study indicated that the plant can be further explored for isolation of antileishmanial and antimicrobial compounds, which could be used for drug development.

Antileishmanial Carbasugars from Geosmithia langdonii

Two new carbasugar-type metabolites, (1 S,2 R,3 R,4 R,5 R)-2,3,4-trihydroxy-5-methylcyclohexyl-2',5'-dihydroxybenzoate (1) and (1 S,2 S,3 S,4 R,5 R)-4-[(2',5'-dihydroxybenzyl)oxy]-5-methylcyclohexane-1,2,3-triol (2), were isolated from the filamentous fungus Geosmithia langdonii isolated from cotton textiles from Assiut, Egypt. The structures of 1 and 2 were elucidated based on comprehensive 1D and 2D NMR and MS data. Compounds 1 and 2 showed antileishmanial activity against Leishmania donovani with IC₅₀ values of 100 and 57 μM, respectively. The (1 S,2 R,3 R,4 R,5 R) absolute configuration of carbasugar 1 was assigned via 2D NMR and experimental and calculated electronic circular dichroism (ECD) data. Similarly, the tentative structure of compound 2 was shown to possess a (1 S,2 S,3 S,4 R,5 R) absolute configuration via comparing its experimental ECD data and the specific rotation with 1 as well as examining the energy-minimized 3D computational models of compounds 1 and 2.

Photodynamic inactivation as an emergent strategy against foodborne pathogenic bacteria in planktonic and sessile states

Foodborne microbial diseases are still considered a growing public health problem worldwide despite the global continuous efforts to ensure food safety. The traditional chemical and thermal-based procedures applied for microbial growth control in the food industry can change the food matrix and lead to antimicrobial resistance. Moreover, currently applied disinfectants have limited efficiency against biofilms. Therefore, antimicrobial photodynamic therapy (aPDT) has become a novel alternative for controlling foodborne pathogenic bacteria in both planktonic and sessile states. The use of aPDT in the food sector is attractive as it is less likely to cause antimicrobial resistance and it does not promote undesirable nutritional and sensory changes in the food matrix. In this review, aspects on the antimicrobial photodynamic technology applied against foodborne pathogenic bacteria and studied in recent years are presented. The application of photodynamic inactivation as an antibiofilm strategy is also reviewed.

Influences of light on growth, reproduction and hypocrellin production by Shiraia sp. SUPER-H168

Light is a very important signal for fungi since it influences many different physiological responses. The effects of dark or light at different wavelengths on growth, reproduction and hypocrellins of Shiraia sp. SUPER-H168 were studied: dark, white, red, yellow, green, blue and purple. All incubations under different light conditions had significant stimulating effects on aerial hyphae and suppressing effects on hypocrellin biosynthesis compared with dark incubation. Under blue and purple light especially blue light, the colonies with profuse growth of aerial mycelium were formed. Hypocrellin production reached 13.73 mg per dish under dark condition, and decreased to 4.01 mg and 2.83 mg per dish under white and blue light, respectively. Light condition not only influenced hypocrellin production but also influenced the composition of hypocrellins. Four types of hyphae, namely surface, aerial, biofilm and penetrative hyphae, were observed by light microscopy and SEM. This study found that biofilm hyphae was so closely connected with production of secondary metabolites, and hypocrellins were only produced by biofilm hyphae. Light promoted sexual development and inhibited asexual reproduction, especially blue light strongly inhibited asexual development.

Synthesis of carbon dots from Hypocrella bambusae for bimodel fluorescence/photoacoustic imaging-guided synergistic photodynamic/photothermal therapy of cancer

As phototheranostic agents, carbon dots (CDs), have recently drawn considerable attention due to their excellent physicochemical properties. However, the complex synthetic route and high-cost of CDs greatly limit their practical application. To address this issue, given their nearly infinite supply from nature, Hypocrella bambusae is used as the precursor for the preparation of CDs in this study. The obtained Hypocrella bambusae CDs (HBCDs) possess good water solubility, broad absorption (350-800 nm), red-light emission (maximum peak at 610 nm), and low biotoxicity. Moreover, HBCDs can highly generate ¹O₂ (0.38) and heat (27.6%) under 635 nm laser irradiation. These excellent properties of HBCDs capacitate them to be utilized for bimodal fluorescence/photoacoustic imaging-guided synergistic photodynamic therapy (PDT)/photothermal therapy (PTT). This work provides a new candidate for tumor treatment with the combination of PDT and PTT, and explores a novel approach for the preparation of CD-based phototheranostic agents with natural biomass as raw carbon sources.

Synthesis and Biological Evaluation of 8-Quinolinamines and Their Amino Acid Conjugates as Broad-Spectrum Anti-infectives

In the search of therapeutic agents for emerging drug-resistant parasites, the synthesis of newer classes of 8-quinolinamines has emerged as a successful chemotherapeutic approach. We report synthesis of 8-quinolinamines bearing 5-alkoxy, 4-methyl, and 2-tert-butyl groups in the quinoline framework and their amino acid conjugates as broad-spectrum anti-infectives. 8-Quinolinamines exhibited potent in vitro antimalarial activity [IC50 = 20-4760 ng/mL (drug-sensitive Plasmodium falciparum D6 strain) and IC50 = 22-4760 ng/mL (drug-resistant P. falciparum W2 strain)]. The most promising analogues have cured all animals at 25 mg/kg/day against drug-sensitive Plasmodium berghei and at 50 mg/kg/day against multidrug-resistant Plasmodium yoelii nigeriensis infections in Swiss mice. The in vitro antileishmanial activities (IC50 = 0.84-5.0 μg/mL and IC90 = 1.95-7.0 μg/mL) comparable to standard drug pentamidine were exhibited by several of the synthesized 8-quinolinamines. At the same time, very promising antifungal activities (Candida albicans-IC50 = 4.93-19.38 μg/mL; Candida glabrata-IC50 = 3.96-19.22 μg/mL; Candida krusei-IC50 = 2.89-18.95 μg/mL; Cryptococcus neoformans-IC50 = 0.67-18.64 μg/mL; and Aspergillus fumigatus-IC50 = 6.0-19.32 μg/mL) and antibacterial activities (Staphylococcus aureus-IC50 = 1.33-18.9 μg/mL; methicillin-resistant S. aureus-IC50 = 1.38-15.34 μg/mL; and Mycobacterium intracellulare-IC50 = 3.12-20 μg/mL) were also observed. None of the 8-quinolinamines exhibited cytotoxicity and therefore are a promising structural class of compounds as antiparasitic and antimicrobials.

Evaluation of Triazole and Isoxazole Derivatives as Potential Anti-infective Agents

A series of isoxazole and triazole derivatives, with interesting bioactive scaffolds, were examined for their in vitro antibacterial, antifungal, and antiprotozoal activities. These compounds exhibited antitrypanosomal activity comparable to difluoromethylornithine (DMFO), a drug used in the treatment of human African trypanosomiasis. Isoxazole analogues 1, 3 and 4, and triazole derivatives 16, 17, 28, 37, 40 and 42 showed the highest antitrypanosomal activity with IC₅₀ values of 17.89, 1.82, 10.38, 10.26, 11.77, 9.29, 3.93, 2.11, and 0.93 μM, respectively. Compounds 40 and 42 showed the most potent activity against Leishmania donovani amastigotes with IC₅₀ values of 18.28 and 10.54 μM, respectively. Compound 42 showed the most potent activity against Leishmania donovani macrophage internalized amastigotes with an IC₅₀ value of 8.32 μM. Conjugate triazoles 40-43 displayed potential antimalarial activity against chloroquine-resistant W2 and chloroquine sensitive D6 Plasmodium falciparum strains (IC₅₀ value range from 0.58 to 8.36 μM). Compound 37 showed antibacterial activity against Staphylococcus aureus, MRSA and Mycobacterium intracellulare with IC₅₀ values of 15.53, 14.22 and 47.45 μM, respectively. None of the compounds exhibited antifungal activity.

An assessment on the role of endophytic microbes in the therapeutic potential of Fagonia indica

Background

Natural products of animals, plants and microbes are potential source of important chemical compounds, with diverse applications including therapeutics. Endophytic bacteria that are especially associated with medicinal plants presents a reservoir of therapeutic compounds. Fagonia indica has been recently investigated by numerous researchers because of its striking therapeutic potential especially in cancer. It is also reported that endophytes play a vital role in the biosynthesis of various metabolites; therefore we believe that endophytes associated with F. indica are of crucial importance in this regard. The present study aims successful isolation, molecular identification of endophytic bacteria and their screening for bioactive metabolites quantification and in vitro pharmacological activities.

Methods

16S rRNA gene sequencing was used for the identification of isolated endophytic bacteria. Methanolic extracts were evaluated for total phenolic contents (TPC), total flavonoids contents (TFC), DPPH free radical scavenging activity, reducing power and total anti-oxidant assays were performed. And also screened for antibacterial and antifungal activities by disc diffusion method and their MIC were calculated by broth dilution method using microplate reader. Further, standard protocols were followed for antileishmanial activity and protein kinase inhibition. Analysis and statistics were performed using SPSS, Table curve and Origin 8.5 for graphs.

Results

Bacterial strains belonging to various genera (Bacillus, Enterobacter, Pantoea, Erwinia and Stenotrophomonas) were isolated and identified. Total phenolic contents and total flavonoids contents varies among all the bacterial extracts respectively in which Bacillus subtilis showed high phenolic contents 243 µg/mg of gallic acid equivalents (GAE) and Stenotrophomonas maltophilia showed high flavonoids contents 15.9 µg/mg quercitin equivalents (QA), total antioxidant capacity (TAC) 37.6 µg/mg of extract, reducing power (RP) 206 µg/mg of extract and 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity with 98.7 μg/mL IC₅₀ value. Although all the extracts tested were active to inhibit growth of selected pathogenic microbes (bacteria and fungi), but significant antibacterial activity was observed against Klebsiella pneumonia and B. subtilis. An Enterobacter cloaca was active against Leishmania tropica with IC₅₀ value of 1.4 µg/mg extracts. B. subtilis and Bacillus tequilensis correspondingly exhibit significant protein kinase inhibition of 47 ± 0.72 and 42 ± 1.21 mm bald zones, indicating anti-infective and antitumor potential.

Conclusions

Our findings revealed that crude extracts of selected endophytic bacteria from F. indica possess excellent biological activities indicating their potential as an important source of antibiotics (antifungal, antibacterial) compounds.

Poly(lactic-co-glycolic) acid nanoparticles improve oral bioavailability of hypocrellin A in rat

The release of HA from PLGA/HA NPs was carried by dissolving PLGA/HA NPs in artificial gastric (pH 1.5), intestinal (pH 6.8) and blood (pH 7.4) media.

Sonodynamic action of hypocrellin B triggers cell apoptoisis of breast cancer cells involving caspase pathway

OBJECTIVES

The aim of the present study is to investigate the effects of sonodynamic action of hypocrellin B on human breast cancer cells and further explore its underlying mechanisms.

METHODS

The cell viability of breast cancer MDA-MB-231 cells was examined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay. Alterations on cell apoptosis, intracellular reactive oxygen species generation (ROS), mitochondrial membrane potential, and DNA fragmentation was analyzed by flow cytometer. The subcellular localization of hypocrellin B was assessed by a confocal laser scanning microscope. Mitochondria damage and nuclear morphological changes were observed under a fluorescence microscope. To further explore whether caspase pathway was involved in cell apoptotic induction of sonodynamic action of hypocrellin B, the pan-caspase inhibitor Z-Val-Ala-DL-Asp (ome)-Fluoromethylketone (z-VAD-fmk) was added to the cells one hour prior to loading the sonosensitizer, and then cell viability and apoptosis were analyzed after hypocrellin B treatment.

RESULTS

Sonodynamic treatment of hypocrellin B HB significantly suppressed cell viability of MDA-MB-231 cells. Sonodynamic action of hypocrellin B caused excessive ROS accumulation, mitochondrial dysfunction, cell apoptosis, DNA fragmentation and nuclear morphological damage. Moreover, the cytotoxicity and cell apoptosis induced by sonodynamic action of hypocrellin B were remarkably rescued by the caspase spectrum inhibitor z-VAD-fmk.

CONCLUSIONS

These results demonstrated that hypocrellin B had significant sonodynamic killing and apoptotic induction effect on breast cancer cells. And cell apoptosis induced by sonodynamic action of hypocrellin B was partly dependent on caspase pathway.

New triterpenoidal saponins from Koelreuteria paniculata

Bioassay guided fractionation and chemical investigation of the ethanolic extract of the aerial parts of Koelreuteria paniculata Laxm. (Sapindaceae), resulted in the isolation and identification of three new triterpenoid saponins 1-3 named Paniculatosoid A-C, along with eleven known compounds. The structures of the isolated compounds were elucidated using 1D and 2D NMR experiments, HRESIMS, and comparison with literature data. The occurrence of tridesmosidic saponin is reported for the first time from family Sapindaceae, as well as it is rarely found in natural saponins. Compounds 4-13 were evaluated for their antibacterial, antifungal, antimalarial and antileishmanial activities. Compound 12 showed weak antibacterial activity against Escherichia coli with an IC₅₀ value of 101 μM. Compounds 12 and 13 showed antimalarial activity against chloroquine-sensitive (D6) Plasmodium falciparum protozoan with IC₅₀ values of 6.46 and 6.95 μM, and against chloroquine-resistant (W2) Plasmodium falciparum protozoan with IC₅₀ values of 9.34 and 4.18 μM.

Insights into the structural patterns of the antileishmanial activity of bi- and tricyclic N-heterocycles

The influence of various structural patterns in a series of novel bi- and tricyclic N-heterocycles on the activity against Leishmania major and Leishmania panamensis has been studied and compounds that are active in the low micromolar region have been identified. Both quinolines and tetrahydrooxazinoindoles (TOI) proved to have significant antileishmanial activities, while substituted indoles were inactive. We have also showed that a chloroquine analogue induces Leishmania killing by modulating macrophage activation.

Sonodynamic action of hypocrellin B on methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) commonly causes refractory infections and has recently become a serious public health concern. The present study was designed to investigate sonodynamic action of hypocrellin B on MRSA. A MRSA strain (ATCC BAA-43) was used in the present study. The dark toxicity of hypocrellin B on MRSA and its uptake in MRSA first were measured. And then bacteria were incubated with hypocrellin B and exposed to ultrasound. After sonodynamic treatment, colony forming unit assay and bacterial viability assay were conducted. Membrane permeability assay, DNA fragmentation assay, and DNA synthesis assay were also performed to examine the underlying mechanism. The results showed that hypocrellin B at concentrations of up to 500 μM had no toxicity to MRSA in the dark. After incubation for 50 min, hypocrellin B could be maximally absorbed by MRSA, and exhibited significant sonodynamic activity in a dose-dependent manner. The 5-log reduction in colony forming unit (CFU) was observed after hypocrellin B (40 μM) treatment at an intensity of 1.38 W/cm(2) ultrasound for 5 min. Compared to the control, hypocrellin B alone and ultrasound sonication alone group, more dead cells were found and bacterial membrane integrity was notably damaged after sonodynamic treatment of hypocrellin B. However, no remarkable DNA damage was found in MRSA after sonodynamic treatment of hypocrellin B. All the findings demonstrated that hypocrellin B could serve as a potential antibacterial sonosensitizer to significantly cause damage to the membrane integrity of MRSA and inhibit its growth under ultrasound sonication.

Trapping toxins within lipid droplets is a resistance mechanism in fungi

Lipid droplets (LDs) act as intracellular storage organelles in most types of cells and are principally involved in energy homeostasis and lipid metabolism. However, the role of LDs in resistance to toxins in fungi remains largely unknown. Here, we show that the trapping of endogenous toxins by LDs is a self-resistance mechanism in the toxin producer, while absorbing external lipophilic toxins is a resistance mechanism in the toxin recipient that acts to quench the production of reactive oxygen species. We found that an endolichenic fungus that generates phototoxic perylenequinones (PQs) trapped the PQs inside LDs. Using a model that incorporates the fungicidal action of hypocrellin A (HA), a PQ derivative, we showed that yeast cells escaped killing by trapping toxins inside LDs. Furthermore, LD-deficient mutants were hypersusceptible to HA-mediated phototoxins and other fungicides. Our study identified a previously unrecognised function of LDs in fungi that has implications for our understanding of environmental adaptation strategies for fungi and antifungal drug discovery.

Sonodynamic action of hypocrellin B on biofilm-producing Staphylococcus epidermidis in planktonic condition

Staphylococcus epidermidis is an opportunistic pathogen causing biofilm-associated infections. To investigate sonodynamic action of hypocrellin B on biofilm-producing Staphylococcus epidermidis in planktonic culture, a biofilm-producing strain Staphylococcus epidermidis (ATCC 35984) was incubated with hypocrellin B and then exposed to ultrasound at intensity (ISATA) of 1.56 W/cm(2) with a frequency of 1 MHz in continuous mode for 5 min. After sonodynamic treatment of hypocrellin B, the bacterial growth was measured using the colony counting method. Bacterial membrane integrity was investigated using a flow cytometry with propidium iodide staining. Intracellular reactive oxygen species (ROS) level was measured using a flow cytometry with DCFH-DA staining. The results showed that sonodynamic action of hypocrellin B significantly induced survival reduction of Staphylococcus epidermidis in a hypocrellin B dose-dependent manner, and a 4-log reduction was observed after the combined treatment of hypcorellin B (40 μM) and ultrasound sonication with the intensity of 1.56 W/cm(2) for 5 min. Bacterial membrane integrity was notably damaged and the level of intracellular ROS level was remarkably increased after sonodynamic treatment. The findings demonstrated that sonodynamic action of hypocrellin B had significant antibacterial activity on biofilm-producing Staphylococcus epidermidis in planktonic condition probably through increasing intracellular ROS level to cause damage to bacterial membrane integrity.

Enhanced effect of photodynamic therapy in ovarian cancer using a nanoparticle drug delivery system

Nanoparticles are promising novel drug delivery carriers that allow tumor targeting and controlled drug release. In the present study, we prepared poly butyl-cyanoacrylate nanoparticles (PBCA-NP) entrapped with hypocrellin B (HB) to improve the effect of photodynamic therapy (PDT) in ovarian cancer. An ovarian cancer ascites model using Fischer 344 rats and PBCA-NP entrapped with HB (HB-PBCA-NP) were formed successfully. The pharmacodynamic characteristics and biodistribution of the HB-PBCA-NP system were evaluated by comparison with HB dimethyl sulfoxide (HB-DMSO) and testing at various time-points following intraperitoneal drug administration. HB-PBCA-NP-based PDT combined with cytoreductive surgery was then administrated to the tumor-bearing animals. Kaplan-Meier survival analysis was performed to assess the therapeutic effect of the nanoparticle system. The serum HB concentration peaked 4 h after drug administration in the nanoparticle system, and 1 h with HB-DMSO. The peak exposure time of tumor tissues was also extended (4 vs. 2 h), and PBCA-NP remained present for much longer than HB-DMSO. Although PDT combined with surgery prolonged the survival time significantly compared with surgery alone (84 days, P<0.05), there was no significant difference in the survival time of animals that received either HB-PBCA-NP- or HB-DMSO-based PDT after cytoreductive surgery (99 vs. 95 days, P=0.293). PBCA-NP exhibited potential advantages in controlled drug release and tumor targeting, which was beneficial for HB-based PDT. PDT combined with surgery prolonged the survival time, suggesting that this might be an alternative treatment option for ovarian cancer.

Sulfated phenolic compounds from Limonium caspium: Isolation, structural elucidation, and biological evaluation

Three new compounds, (2S,3S)-5-methyldihydromyricetin (1), (2S,3S)-5-methyldihydromyricetin-3'-O-sulfate (2) and β-d-glucopyranoside, 3-methyl, but-3-en-1-yl 4-O-α-l-rhamnopyranosyl (3) have been isolated from the Limonium caspium, together with dihydromyricetin (4), dihydromyricetin-3'-O-sulfate (5), myricetin-3'-O-sulfate (6), 5-methylmyricetin (7), myricetin (8), myricetin-3-O-β-glucoside (9), as well as phloridzin (10), and tyramine (11). Compounds 5 and 6 were isolated for the first time as acids. This is the first report of all these compounds from this plant. Their structures were established by extensive NMR studies ((1)H NMR, (13)C NMR, DEPT, (1)H-(1)H COSY, HSQC, HMBC) as well as HRESIMS. All isolated compounds were evaluated for their antibacterial, antifungal, antimalarial and antileishmanial activities. Compounds 7, 8 and 9 exhibited good antifungal activity against Candida glabrata with IC50 values of 6.79, 15.37 and 8.53μg/mL, respectively. Compound 8 displayed significant antimalarial activity against resistant and sensitive strains of Plasmodium falciparum with IC50 values of 1.82 and 1.51μg/mL, respectively. Compounds 1, 4, 6, 8 and 9 showed excellent activity against Trypanosoma brucei with IC50 values of 6.93, 9.65, 8.52, 7.67 and 6.31μg/mL, respectively. To date, this is the first report on the phytochemical and biological activity of secondary metabolites from L. caspium.

Characterization and phylogenetic analysis of the mitochondrial genome of Shiraia bambusicola reveals special features in the order of pleosporales

Shiraia bambusicola P. Henn. is a pathogenic fungus of bamboo, and its fruiting bodies are regarded as folk medicine. We determined and analyzed its complete mitochondrial DNA sequence (circular DNA molecule of 39,030 bp, G + C content of 25.19%). It contains the typical genes encoding proteins involved in electron transport and coupled oxidative phosphorylation (nad1-6 and nad4L, cob and cox1-3), one ATP synthase subunit (atp6), 4 hypothetical proteins, and two genes for large and small rRNAs (rnl and rns). There is a set of 32 tRNA genes comprising all 20 amino acids, and these genes are evenly distributed on the two strands. Phylogenetic analyses based on concatenated mitochondrial proteins indicated that S. bambusicola clustered with members of the order Pleosporales, which is in agreement with previous results. The gene arrangements of Dothideomycetes species contained three regions of gene orders partitioned in their mitochondrial genomes, including block 1 (nad6-atp6), block 2 (nad1-cox3) and block 3 (genes around rns). S. bambusicola displayed unique special features that differed from the other Pleosporales species, especially in the coding regions around rns (trnR-trnY). Moreover, a comparison of gene orders in mitochondrial genomes from Pezizomycotina revealed that although all encoded regions are located on the same strand in most Pezizomycotina mtDNAs, genes from Dothideomycetes species had different orientations, as well as diverse positions and colocalization of genes (such as cox3, cox1-cox2 and nad2-nad3); these distinctions were regarded as class-specific features. Interestingly, two incomplete copies of the atp6 gene were found on different strands of the mitogenomic DNA, a finding that has not been observed in the other analyzed fungal species. In our study, mitochondrial genomes from Dothideomycetes species were comprehensively analyzed for the first time, including many species that have not appeared in previous reports.

The cleavage of perylenequinones through photochemical oxidation acts as a detoxification mechanism for the producer

The light driven oxygenation cleavage of perylenequinones into nontoxic agents acts as a detoxification mechanism for the toxin producer.