A new phenolic compound with anticancer activity from the wood of Millettia leucantha

Lactate dehydrogenase is the Achilles' heel of Lyme disease bacterium Borreliella burgdorferi

As a zoonotic pathogen, the Lyme disease bacterium Borreliella burgdorferi has evolved unique metabolic pathways, some of which are specific and essential for its survival and thus present as ideal targets for developing new therapeutics. B. burgdorferi dispenses with the use of thiamin as a cofactor and relies on lactate dehydrogenase (BbLDH) to convert pyruvate to lactate for balancing NADH/NAD+ ratios. This report first demonstrates that BbLDH is a canonical LDH with some unique biochemical and structural features. A loss-of-function study then reveals that BbLDH is essential for B. burgdorferi survival and infectivity, highlighting its therapeutic potential. Drug screening identifies four previously unknown LDH inhibitors with minimal cytotoxicity, two of which inhibit B. burgdorferi growth. This study provides mechanistic insights into the function of BbLDH in the pathophysiology of B. burgdorferi and lays the groundwork for developing genus-specific metabolic inhibitors against B. burgdorferi and potentially other tick-borne pathogens as well.

IMPORTANCE

Lyme disease (LD) is the most commonly reported tick-borne illness in the U.S. and Europe, and its geographic distribution is continuously expanding worldwide. Though early LD can be treated with antibiotics, chronic LD is recalcitrant to antibiotic treatments and thus requires multiple courses of antibiotic therapy. Currently, there are no human vaccines nor prophylactic antibiotics to prevent LD. As the causative agent of LD, Borreliella burgdorferi has evolved unique metabolic pathways, some of which are specific and essential for its survival and thus present as ideal targets for developing new therapeutics. By using an approach of genetics, biochemistry, structural biology, drug screening, and animal models, this report provides evidence that lactate dehydrogenase can be a potential target for developing genus-specific metabolic inhibitors against B. burgdorferi and potentially other tick-borne pathogens as well.

Lactate dehydrogenase is the Achilles' heel of Lyme disease bacterium Borreliella burgdorferi

As a zoonotic pathogen, the Lyme disease bacterium Borreliella burgdorferi has evolved unique metabolic pathways, some of which are specific and essential for its survival and thus present as ideal targets for developing new therapeutics. B. burgdorferi dispenses with the use of thiamin as a cofactor and relies on lactate dehydrogenase (BbLDH) to convert pyruvate to lactate for balancing NADH/NAD + ratios. This report first demonstrates that BbLDH is a canonical LDH with some unique biochemical and structural features. A loss-of-function study then reveals that BbLDH is essential for B. burgdorferi survival and infectivity, highlighting its therapeutic potential. Drug screening identifies four previously unknown LDH inhibitors with minimal cytotoxicity, two of which inhibit B. burgdorferi growth. This study provides mechanistic insights into the function of BbLDH in the pathophysiology of B. burgdorferi and lays the groundwork for developing genus-specific metabolic inhibitors against B. burgdorferi and potentially other tick-borne pathogens as well.

Protective Effects of Anethole in Foeniculum vulgare Mill. Seed Ethanol Extract on Hypoxia/Reoxygenation Injury in H9C2 Heart Myoblast Cells

BACKGROUND

Active compounds from plants and herbs are increasingly incorporated into modern medical systems to address cardiovascular diseases (CVDs). Foeniculum vulgare Mill., commonly known as fennel, is an aromatic medicinal plant and culinary herb that is popular worldwide.

METHODS

Protective effects against cellular damage were assessed in the H9C2 cardiomyocyte hypoxia/reoxygenation (H/R) experimental model. The identities of phytochemicals in FVSE were determined by GC-MS analysis. The phytochemical's potential for nutrients and pharmacokinetic properties was assessed by ADMET analysis.

RESULTS

GC-MS analysis of the ethanol extracts of F. vulgare identified 41 bioactive compounds, with four prominent ones: anethole, 1-(4-methoxyphenyl)-2-propanone, ethoxydimethylphenylsilane, and para-anisaldehyde diethyl acetal. Among these, anethole stands out due to its potential for nutrients and pharmacokinetic properties assessed by ADMET analysis, such as bioavailability, lipophilicity, flexibility, and compliance with Lipinski's Rule of Five. In the H/R injury model of H9C2 heart myoblast cells, FVSE and anethole suppressed H/R-induced reactive oxygen species (ROS) generation, DNA double-strand break damage, nuclear condensation, and the dissipation of mitochondrial membrane potential (ΔΨm).

CONCLUSIONS

These findings highlight the therapeutic potential of FVSE and its prominent component, anethole, in the treatment of CVDs, particularly those associated with hypoxia-induced damage.

Engineering Streptomyces albus B4 for Enhanced Production of (R)-Mellein: A High-Titer Heterologous Biosynthesis Approach

The natural compound (R)-(-)-mellein exhibits antiseptic and fungicidal activities. We investigated its biosynthesis using the polyketide synthase encoded by SACE_5532 (pks8) from Saccharopolyspora erythraea heterologously expressed in Streptomyces albus B4, a chassis chosen for its fast growth, genetic manipulability, and ample large short-chain acyl-CoA precursor supply. High-level heterologous (R)-(-)-mellein yield was achieved by pks8 overexpression and duplication. The precursor supply pathways were strengthened by overexpression of SACE_0028 (encoding acetyl-CoA carboxylase) and four genes involved in β-oxidation (fadD, fadE, fadB, and fadA). Cell growth inhibition by (R)-(-)-mellein production at high concentration was relieved by in situ adsorption using Amberlite XAD16 resin. The final strain, B4mel12, produced (R)-(-)-mellein at 6395.2 mg/L in shake-flask fermentation. Overall, this is the first report of heterologous (R)-(-)-mellein synthesis in microorganism with a high titer. (R)-(-)-mellein prototype in this study opens a possibility for the overproduction of valuable melleins in S. albus B4.

Study on the absolute configuration and biological activity of rotenoids from the leaves and twigs of Millettia pyrrhocarpa Mattapha, Forest & Hawkins, sp. Nov

BACKGROUND

M. pyrrhocarpa is a new plant in the Fabaceae: Faboideae family that is found in Thailand. A literature search revealed that the Milletia genus is rich in bioactive compounds possessing a wide range of biological activities. In this study, we aimed to isolate novel bioactive compounds and to study their bioactivities.

METHODS

The hexane, ethyl acetate, and methanol extracts from the leaves and twigs of M. pyrrhocarpa were isolated and purified using chromatography techniques. These extracts and pure compounds were tested in vitro for their inhibitory activities against nine strains of bacteria, as well as their anti-HIV-1 virus activity and cytotoxicity against eight cancer cell lines.

RESULTS

Three rotenoids, named 6aS, 12aS, 12S-elliptinol (1), 6aS, 12aS, 12S-munduserol (2), dehydromunduserone (3), and crude extracts were evaluated for antibacterial, anti-HIV, and cytotoxic activities. It was found that compounds 1-3 inhibited the growth of nine strains of bacteria, and the best MIC/MBC values were obtained at 3/ > 3 mg/mL. The hexane extract showed anti-HIV-1 RT with the highest %inhibition at 81.27 at 200 mg/mL, while 6aS, 12aS, 12S-elliptinol (1) reduced syncytium formation in 1A2 cells with a maximum EC₅₀ value of 4.48 μM. Furthermore, 6aS, 12aS, 12S-elliptinol (1) showed cytotoxicity against A549 and Hep G2 cells with maximum ED₅₀ values of 2.27 and 3.94 μg/mL.

CONCLUSION

This study led to the isolation of constituents with potential for medicinal application, providing compounds (1-3) as lead compounds against nine strains of bacteria. The hexane extract showed the highest %inhibition of HIV-1 virus, Compound 1 showed the best EC₅₀ in reducing syncytium formation in 1A2 cells, and it also showed the best ED₅₀ against human lung adenocarcinoma (A549) and human hepatocellular carcinoma (Hep G2). The isolated compounds from M. pyrrhocarpa offered significant potential for future medicinal application studies.

Cytotoxic effect and antioxidant activity of pterocarpans from Millettia aboensis root

Chemical analysis of the methanol extract of the root bark of Millettia aboensis led to the isolation of homopterocarpin (1), secundiflorol I (2), and maackain (3). The structures of these compounds were elucidated based on their MS and NMR spectra. The crude methanol root extract was screened for its cytotoxic activity on mouse lymphoma cell line (L5178Y), and the isolated compounds were tested for their antioxidant activity using a 2, 2-diphenylhydrazyl (DPPH) radical scavenging model. The crude methanol root extract gave a percentage growth inhibition of 87.5% on the mouse lymphoma cell line (L5178Y). Compound 3 gave the highest antioxidant activity with an IC₅₀ of 83 µg/ml. These compounds can serve as leads for anticancer agents.

Identification of Mellein as a Pathogenic Substance of Botryosphaeria dothidea by UPLC-MS/MS Analysis and Phytotoxic Bioassay

Botryosphaeria dothidea is a pathogenic fungus that can cause apple ring rot, a destructive apple disease in China. There have been reports on its molecular pathogenesis, but the pathogenic substances still remain unknown. In the present study, instrument analysis including UPLC-high-resolution mass spectrometry (HRMS) and nuclear magnetic resonance showed that B. dothidea fermentation broth contained (R)-(-)-mellein, a well-known fungal enantiomer of mellein. For further confirmation, a UPLC-MS/MS method for the determination of mellein was developed and validated. By this method, mellein was found to also exist in B. dothidea-infected apple fruits and branches with concentration ranges of 0.14-0.94 and 5.88-80.29 mg/kg, respectively. The concentration in fruits reached a peak at 48 h after pathogen inoculation, while a sustained concentration increase was achieved within 11 days for branches. Simultaneously, it was evident that there was a relation between disease spot expansion and mellein production kinetics in apple tissue. Phytotoxic bioassay showed that mellein could cause discoloration and death of apple leaves and browning in stems. Therefore, we confirmed that mellein was one of the pathogenic substances of B. dothidea. The present study provided additional data for the research on the pathogenesis of this pathogen.

A review on genus Millettia: Traditional uses, phytochemicals and pharmacological activities

The genus Millettia belongs to Fabaceae includes 200 species which are distributed in tropical and subtropical regions of the world. Plants belong to this genus are used as folkloric medicine, for the treatment of different ailments like in wound healing, boil, sores, skin diseases, snake bite, muscle aches, pains, rheumatic arthritis, and gynaecological diseases. The aim of the review is to provide updated, comprehensive and categorized information on the aspects of ethnobotanical, phytochemical, pharmacological uses and toxicity of genus Millettia in order to identify their therapeutic potential and generate space for future research opportunities. The present study comprises of isolated flavonoids, phenolic compounds, phytosterols, saponins, alkaloids, polysaccharides, terpenoids and resins and pharmacological activities of various Millettia species. The relevant data were searched by using the keyword "Millettia" in different scientific databases like, "Google Scholar"; "NISCAIR repository"; "Pub Med"; "Science Direct"; "Scopus" and the taxonomy is validated by "The Plant List". This review discusses the existing information of the traditional evaluation as well as phytochemical and pharmacological evaluation of the extract and active constituents of the genus "Millettia". This review confirms that several Millettia species have emerged as a high-quality medicine in a traditional system for arthritis, wound healing, inflammation, skin diseases. Numerous conventional uses of Millettia species have been validated by modern pharmacology research. Intensive investigations of the genus Millettia relating to phytochemistry and pharmacology, especially their mechanism of action, safety, and efficacy could be the future research interests by the researcher in the area of phytomedicine.

Mitochondrial Targeting in an Anti-Austerity Approach Involving Bioactive Metabolites Isolated from the Marine-Derived Fungus Aspergillus sp

The tumor microenvironment is a nutrient-deficient region that alters the cancer cell phenotype to aggravate cancer pathology. The ability of cancer cells to tolerate nutrient starvation is referred to as austerity. Compounds that preferentially target cancer cells growing under nutrient-deficient conditions are being employed in anti-austerity approaches in anticancer drug discovery. Therefore, in this study, we investigated physcion (1) and 2-(2',3-epoxy-1',3',5'-heptatrienyl)-6-hydroxy-5-(3-methyl-2-butenyl) benzaldehyde (2) obtained from a culture extract of the marine-derived fungus Aspergillus species (sp.), which were isolated from an unidentified marine sponge, as anti-austerity agents. The chemical structures of 1 and 2 were determined via spectroscopic analysis and comparison with authentic spectral data. Compounds 1 and 2 exhibited selective cytotoxicity against human pancreatic carcinoma PANC-1 cells cultured under glucose-deficient conditions, with IC₅₀ values of 6.0 and 1.7 µM, respectively. Compound 2 showed higher selective growth-inhibitory activity (505-fold higher) under glucose-deficient conditions than under general culture conditions. Further analysis of the mechanism underlying the anti-austerity activity of compounds 1 and 2 against glucose-starved PANC-1 cells suggested that they inhibited the mitochondrial electron transport chain.

Melleins-Intriguing Natural Compounds

Melleins are 3,4-dihydroisocoumarins mainly produced by fungi, but also by plants, insects and bacteria. These specialized metabolites play important roles in the life cycles of the producers and they are involved in many biochemical and ecological processes. This review outlines the isolation and chemical and biological characterizations of natural-occurring melleins from the first report of (R)-mellein in 1933 to the most recent advances in their characterization in 2019. In addition, the pathways that could be involved in mellein biosynthesis are discussed, along with the enzymes and genes involved.

Anti-inflammatory secondary metabolites from the stems of Millettia dielsiana Harms ex Diels

A phytochemical investigation for the constituents of the stems of Millettia dielsiana Harms ex Diels resulted in the isolation of a new isoflavone glycoside, mildiside A (1), and 14 known compounds (2-15). Their chemical structures were determined using a combination of IR, NMR, MS, and optical rotation analysis, as well as comparison with the literature data. The ethanolic (EtOH) extract and several isolated compounds exert the inflammatory effect of nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated murine RAW264.7 macrophage cells.

Anti-inflammatory pterocarpanoids from the roots of Pongamia pinnata

A phytochemical study on the roots of Pongamia pinnata afforded 11 pterocarpanoids, including three new compounds. The structures of the isolated compounds were determined by 1D and 2D NMR and HRESIMS data. The absolute configurations of the new compounds were assigned via analysis of the specific rotations and electronic circular dichroism (ECD) spectra. The isolates were evaluated for their inhibitory effects on nitric oxide (NO) production in LPS-stimulated BV-2 microglial cells. Six compounds exhibited inhibitory effects against NO production, and compound 5 showed the best activity with an IC₅₀ value at 12.0 μM.

Physcion and physcion 8-O-β-glucopyranoside: A review of their pharmacology, toxicities and pharmacokinetics

Anthraquinones constitute an important class of natural and synthetic compounds with a broad scope of pharmacological including anti-bacterial, antioxidant, laxative, anti-tumor and other activities. Physcion and physcion 8-O-β-glucopyranoside (PG) are common anthraquinones existed in various plants. Emerging studies suggested that physcion and PG not only exert anti-tumor, anti-microbial, anti-inflammatory, anti-oxidant, optical-related, enzyme inhibitory, lipid regulation and neuroprotective activities, but also lead to hepatotoxicity, renal toxicity and genetic damage. Besides, a growing number of pharmacokinetics researches of physcion and PG also have been conducted. However, no review of physcion or PG have been published by now, so the aim of present review is to give a comprehensive summary and analysis of the pharmacology, toxicity and pharmacokinetics of physcion and PG by consulting all the currently available literatures published in PubMed then give a future prospects about it.

Wood volatiles as attractants of the confused flour beetle, Tribolium confusum (Coleoptera: Tenebrionidae)

Confused flour beetles are serious pests of stored grain products, and therefore, it is important to efficiently monitor and control their populations. Aggregation pheromones are commercially used for monitoring this beetle but their efficacy has been questioned and they may be inadequate for practical use. Food attractants as well as pheromones are commonly used for monitoring stored-product insects. However, food attractants may not be effective in the case of food handling facilities, which are already filled with food odours. The ancestors of flour beetles may have been associated with dead or decomposing woody vegetation, so we investigated the attractiveness of several wood odours to beetles using a pitfall olfactometer. The beetles were strongly attracted to all wood odours tested: Castanea crenata, Magnolia obovata, Paulownia tomentosa, Prunus jamasakura, and Zelkova serrata. The attractiveness of these wood odours was also stronger than that of the odours of the usual food of these beetles. Supercritical CO2 extracts of these species of wood were also attractive to the beetles. The Z. serrata extract was the most attractive among these extracts, and was further analysed by gas chromatography mass spectrometry. One major compound, (-)-mellein, was detected in the extract. Synthetic (±)-mellein attracted the beetles.

Cicadamides A and B,N-Acetyldopamine Dimers From the InsectPeriostracum cicadae

Two new N-acetyldopamine dimers, cicadamides A (1) and B (2), and 8 known compounds were isolated from the medicinal insect Periostracum cicadae. Their structures including absolute configurations were assigned by spectroscopic and computational methods. Biological activities of compounds 1, (+)-2, and (–)-2 toward human cancer cells BGC-823, HepG2, and A549 were evaluated.

Metabolites of Medicarpin and Their Distributions in Rats

Medicarpin is a bioactive pterocarpan that has been attracting increasing attention in recent years. However, its metabolic fate in vivo is still unknown. To clarify its metabolism and the distribution of its metabolites in rats after oral administration, the HPLC-ESI-IT-TOF-MSⁿ technique was used. A total of 165 new metabolites (13 phase I and 152 phase II metabolites) were tentatively identified, and 104, 29, 38, 41, 74, 28, 24, 15, 42, 8, 10, 3, and 17 metabolites were identified in urine, feces, plasma, the colon, intestine, stomach, liver, spleen, kidney, lung, heart, brain, and thymus, respectively. Metabolic reactions included demethylation, hydrogenation, hydroxylation, glucuronidation, sulfation, methylation, glycosylation, and vitamin C conjugation. M1 (medicarpin glucuronide), M5 (vestitol-1'-O-glucuronide) were distributed to 10 organs, and M1 was the most abundant metabolite in seven organs. Moreover, we found that isomerization of medicarpin must occur in vivo. At least 93 metabolites were regarded as potential new compounds by retrieving information from the Scifinder database. This is the first detailed report on the metabolism of ptercarpans in animals, which will help to deepen the understanding of the metabolism characteristics of medicarpin in vivo and provide a solid basis for further studies on the metabolism of other pterocarpans in animals.

Flavonoids from Milletia leucantha and Their Cytotoxicity

Two known chalcones (1–2), five known flavonol derivatives (3 and 5–8) and one flavone (4) were isolated for the first time from fruits of Millettia leucantha Kurz. In addition, 5 was found for the first time from this genus. Their structures were elucidated on the basis of IR, MS, 1D and 2D NMR techniques. Chalcone 1 exhibited moderate cytotoxicity against the MCF-7 cell line with an IC50 value of 50.93 μM, whereas this compound showed inactive cytotoxicity against Vero cells. Compound 2 exhibited cytotoxicity against the KB, NCI-H187 and Vero cell lines with IC50 values of 63.64, 114.44 and 28.44 μM, respectively. Compound 8 only showed cytotoxic activity against the KB cell line with an IC50 value of 110.23 μM.

Estrogenic and cytotoxic potentials of compounds isolated from Millettia macrophylla Benth (Fabaceae): towards a better understanding of its underlying mechanisms

BACKGROUND

Millettia macrophylla was previously reported to have estrogenic effects and to prevent postmenopausal osteoporosis in Wistar rats. So, the study deals with the identification of its secondary metabolites and the evaluation of their estrogenicity and cytotoxicity toward tumoural cells. Thus, 13 known compounds were obtained from successive chromatographic columns and identified by NMR data compared to those previously reported.

METHODS

In vitro estrogenicity of the isolates and the phenolic fraction (PF) of M. macrophylla were performed by E-screen and reporter gene assays, while their cytotoxicity was evaluated by Alamar Blue (resazurin) assay. A 3-days uterotrophic assay and the ability of PF to alleviate hot flushes in ovariectomized adult rats were tested in vivo.

RESULTS

Seven of the 13 secondary metabolites turned to be estrogenic. Only two exhibited cytotoxic effects on MCF-7 and MDA-MB-231 with CC50 values of 110 μM and 160 μM, respectively. PF induced a significant (p < 0.01) MCF-7 cells proliferation and transactivated both ERα and ERβ in the reported gene assay at 10-2 μg/mL. In vivo, PF acted more efficiently than the methanol crude extract, resulting to a significant (p < 0.01) increase in the uterine wet weight, uterine protein level, uterine and vaginal epithelial height at the dose of 10 mg/kg BW. In addition, PF reduced the average duration and frequency of hot flushes induced in rat.

CONCLUSION

These aforementioned results indicate that PF is a good candidate for the preparation of an improved traditional medicine able to alleviate some menopausal complaints such as vaginal dryness and hot flushes. Estrogenic and cytotoxic potentials of compounds isolated from Millettia macrophylla Benth. (Fabaceae): towards a better understanding of its underlying mechanism.

Potent selective monoamine oxidase B inhibition by maackiain, a pterocarpan from the roots of Sophora flavescens

Monoamine oxidase (MAO) catalyzes the oxidation of monoamines and its two isoforms, MAO-A and MAO-B, break down neurotransmitter amines. Of the compounds isolated from the roots of Sophora flavescens, (-)-maackiain (4), a pterocarpan, was found to potently and selectively inhibit human MAO-B, with an IC50 of 0.68μM, and to have a selectivity index of 126.2 for MAO-B. As compared with other herbal natural products, the IC50 value of 4 for MAO-B is one of the lowest reported to date. Genistein (1) highly, effectively and non-selectively inhibited MAO-A and MAO-B with IC50 values of 3.9μM and 4.1μM, respectively. (-)-4-Hydroxy-3-methoxy-8,9-methylenedioxypterocarpan (2) effectively and non-selectively inhibited MAO-A and MAO-B with IC50 values of 20.3μM and 10.3μM, respectively. In addition, compound 4 reversibly and competitively inhibited MAO-B with a Ki value of 0.054μM. Molecular docking simulation revealed that the binding affinity of 4 for MAO-B (-26.6kcal/mol) was greater than its affinity for MAO-A (-8.3kcal/mol), which was in-line with our inhibitory activity findings. Furthermore, Cys172 of MAO-B was found to be a key residue for hydrogen bonding with compound 4. The findings of this study suggest compound 4 be viewed as a new potent, selective, and reversible MAO-B inhibitor, and that compounds 1 and 2 be considered useful lead compounds for the developments of nonselective and reversible MAO inhibitors for the treatment of disorders like Parkinson's disease, Alzheimer disease, and depression.

Flavonoids from the cultured cells of Glycyrrhiza uralensis

Two new flavonoids (1 and 2), along with 14 known ones (3-16), were isolated from the cultured cells of Glycyrrhiza uralensis. Most of them were prenylated flavonoids. Their structures were elucidated on the basis of spectroscopic data analysis. All compounds showed non-cytotoxicity against five human tumor cell lines. The results suggest that plant cultured cells can yield the secondary metabolites that have not been found in parent plant.