Water-soluble matrine-type alkaloids with potential anti-neuroinflammatory activities from the seeds of Sophora alopecuroides

Three new quinolizidine alkaloids from the roots of Sophora tonkinensis

Three new quinolizidine alkaloids (1 - 3), including one new naturally isoflavone and cytisine polymer (3), along with 6 known ones were isolated from the ethanol extract of Sophora tonkinensis Gagnep. Their structures were elucidated by comprehensive spectroscopic data analysis (IR, UV, HRESIMS, 1D and 2D NMR), combined with ECD calculations. The antifungal activity against Phytophythora capsica, Botrytis cinerea, Gibberella zeae, and Alternaria alternata of the compounds was evaluated in a mycelial inhibition assay. Biological tests indicated that compound 3 exhibited strong antifungal activity against P. capsica with EC50 values of 17.7 μg/ml.

Undescribed matrine-type alkaloids from Sophora alopecuroides with anti-inflammatory activity

A phytochemical investigation on the alkaloid fractions of Sophora alopecuroides L. led to the production of 11 undescribed matrine-type alkaloids, sophaloseedlines I-S (1-11), 12 known analogs (12-23), and an unexpected artificial matrine-derived Al(III) complex (24). The corresponding structures were elucidated by the interpretation of spectroscopic analyses, quantum chemical calculation, and six instances (1-4, 18, and 24), verified by X-ray crystallography. The biological activities screening demonstrated that none of the isolates exhibited cytotoxicity against four human cancer cell lines (HepG2, A549, THP-1, and MCF-7) and respiratory syncytial virus (RSV) at 50 μM, while moderate anti-inflammatory activity with IC50 value from 15.6 to 47.8 μM was observed. The key structure-activity relationships of those matrine-type alkaloids for anti-inflammatory effects have been summarized. In addition, the most potent 7-epi-sophoramine (19) and aluminum sophaloseedline T (24) could effectively inhibit the release of pro-inflammatory factors (TNF-α, IL-6, and IL-1β), as well as the expression of iNOS and COX-2 proteins.

Dihydrophenanthro[b]furan derivatives from the tubers of Bletilla striata

Two pairs of new dihydrophenanthro[b]furan enantiomers blephebibnols G-H (1-2), one new dihydrophenanthro[b]furan derivative blephebibnol I (3), along with four known analogues (4-7), were isolated from the tubers of Bletilla striata. Their structures including the absolute configurations were determined by the combination of spectroscopic data analysis, ECD and NMR calculations. Compounds 1a, 1b, and 2b showed inhibition of NO production in LPS-stimulated BV-2 cells, with IC50 values ranging from 4.11 to 14.65 μM. Further mechanistic study revealed that 1a suppressed the phosphorylation of p65 subunit to regulate the NF-κB signaling pathway. In addition, some compounds displayed selective cytotoxic activities against HCT-116, HepG2, A549, or HGC27 cancer cell lines with IC50 values ranging from 0.1 to 8.23 μM.

Research Progress of Natural Matrine Compounds and Synthetic Matrine Derivatives

Matrine is a quinoline alkaloid extracted and separated from the dried root, fruit, and other parts of the plant Sophora flavescens using an organic solvent. Matrine exhibits a variety of biological activities and is widely used in pharmacy, agronomy, and other fields. Due to its low bioavailability, poor chemical stability, and toxicity to the central nervous system, a large number of researchers have searched for matrine derivatives with higher biological activity and safety by modifying its structure. In this review article, the research progress of matrine derivatives obtained using two methods (extraction from Sophora flavescens and structural modifications) from 2018 to 2022 in terms of pharmacological activity, mechanism of action, and structure-activity relationship are presented. The modification of matrine over the past five years has been mainly on the D-ring. Many new matrine alkaloids have been extracted from natural products, some of which have good pharmacological activity, which broadens the strategy for matrine structural modification in the future.

Sophflarine A, a novel matrine-derived alkaloid from Sophora flavescens with therapeutic potential for non-small cell lung cancer through ROS-mediated pyroptosis and autophagy

BACKGROUND

Novel compounds and more efficient treatment options are urgently needed for the treatment of non-small cell lung cancer (NSCLC). The decoction of Sophora flavescens has been used to treat NSCLC in the clinic, and matrine-type alkaloids are generally considered to be the key pharmacodynamic material basis. But the previous study showed that common matrine-type alkaloids exhibit significant cytotoxicity only when at concentrations close to the millimolar (mM) level. The key antitumor alkaloids in S. flavescens seem to have not yet been revealed.

PURPOSE

The aim of this study was to screen water-soluble matrine alkaloid with novel skeleton and enhanced activity from S. flavescens, and to reveal the pharmacological mechanism of its therapeutic effect on NSCLC.

METHODS

Alkaloid was obtained from S. flavescens by chromatographic separation methods. The structure of alkaloid was determined by spectroscopic methods, and single-crystal X-ray diffraction. The mechanism of anti-NSCLC in vitro with cellular models was evaluated by MTT assay, western blotting, cell migration and invasion assay, plate colony-formation assay, tube formation assay, immunohistochemistry assay, hematoxylin and eosin staining. The antitumor efficacy in vivo was test in NSCLC xenograft models.

RESULTS

A novel water-soluble matrine-derived alkaloid incorporating 6/8/6/6 tetracyclic ring system, named sophflarine A (SFA), was isolated from the roots of S. flavescens. SFA had significantly enhanced cytotoxicity compared with the common matrine-type alkaloids, having an IC₅₀ value of 11.3 μM in A549 and 11.5 μM in H820 cells at 48 h. Mechanistically, SFA promoted NSCLC cell death by inducing pyroptosis via activating the NLRP3/caspase-1/GSDMD signaling pathway, and inhibited cancer cell proliferation by increasing the ROS production to activate autophagy via blocking the PI3K/AKT/mTOR signaling pathway. Additionally, SFA also inhibited NSCLC cell migration and invasion by suppressing EMT pathway, and inhibited cancer cell colony formation and human umbilical vein endothelial cell angiogenesis. In concordance with the above results, SFA treatment blocked tumor growth in an A549 cell-bearing orthotopic mouse model.

CONCLUSION

This study revealed a potential therapeutic mechanism of a novel matrine-derived alkaloid, which not only described a rational explanation for the clinical utilization of S. flavescens, but also provided a potential candidate compound for NSCLC treatment.

Two new isoflavones from the roots of Sophora tonkinensis

Two new isoflavones (1 and 2), as well as eight known ones were isolated from the roots of Sophora tonkinensis Gagnep. Compound 1 represents an unprecedented polymerization pattern constructed by isoflavone and cytisine. Their structures were elucidated by comprehensive spectroscopic data analysis, combined with ECD calculations. Compound 1 displayed significant anti-tobacco mosaic virus (TMV) activity compared with the positive control ningnanmycin. Moreover, compound 6 exhibited potent α-glucosidase inhibitory activity with IC₅₀ value of 47.4 mg/L.

Neurological disorders of COVID-19: insights to applications of natural products from plants and microorganisms

In addition to the typical respiratory manifestations, various disorders including involvement of the nerve system have been detected in COVID-19 ranging from 22 to 36%. Although growing records are focusing on neurological aspects of COVID-19, the pathophysiological mechanisms and related therapeutic methods remain obscure. Considering the increased concerns of SARS-CoV-2 potential for more serious neuroinvasion conditions, the present review attempts to focus on the neuroprotective effects of natural compounds as the principle source of therapeutics inhibiting multiple steps of the SARS-CoV-2 infection cycle. The great majority of the natural products with anti-SARS-CoV-2 activity mainly inhibit the attachment, entry and gene expression rather than the replication, assembly, or release. Although microbial-derived natural products comprise 38.5% of the known natural products with neuroprotective effects following viral infection, the neuroprotective potential of the majority of microorganisms is still undiscovered. Among natural products, chrysin, huperzine A, ginsenoside Rg1, pterostilbene, and terrein have shown potent in vitro neuroprotective activity and can be promising for new or repurpose drugs for neurological complications of SARS-CoV-2.

Matrine attenuates bovine mammary epithelial cells inflammatory responses induced by Streptococcus agalactiae through inhibiting NF-κB and MAPK signaling pathways

Streptococcus agalactiae is one of the main pathogens associated with bovine mastitis. The invasion of S. agalactiae in bovine mammary epithelial cells (BMECs) has been implicated as a key event in the pathogenesis of mastitis. Matrine is known for its various pharmacological activities, such as immune response regulation and anti-inflammation. The primary aim of the research was to investigate the preventive effect of matrine on S. agalactiae-induced inflammation in BMECs along with underlying molecular mechanisms. Our data showed matrine at the concentrations of 50-100 μg/mL promoted BMECs proliferation without infection, and decreased cytotoxicity induced by S. agalactiae. Subsequently, BMECs were pre-treated with matrine (50, 75, or 100 μg/mL) for 24 h, followed by the infection with S. agalactiae for an additional 6 h. Pretreatment with matrine followed by S. agalactiae treatment decreased cell apoptosis of BMECs. Also, pretreatment of matrine to BMECs prevented the invasion of S. agalactiae. The mRNA abundances of IL-1β, IL-6, IL-8, and TNF-α were down-regulated in S. agalactiae-infected cells pretreated with matrine. In addition, the greater ratios of protein NF-κB p-p65/p65, p-IκBα/IκBα, p-38/38, and p-ERK/ERK induced by S. agalactiae were attenuated due to matrine treatment. Furthermore, pretreatment of BMECs with matrine impeded the degradation of TAK1 induced by S. agalactiae infection. These results suggest matrine could be a potential modulator in immune response of the mammary gland. In conclusion, matrine prevents cellular damage due to S. agalactiae infection by the modulation of NF-κB and MAPK signaling pathways and pro-inflammatory cytokine production.

Atropisomeric 9,10-dihydrophenanthrene/bibenzyl trimers with anti-inflammatory and PTP1B inhibitory activities from Bletilla striata

Two pairs of novel trimeric dihydrophenanthrene-bibenzyl-dihydrophenanthrene enantiomers (1 and2), the first examples of a dihydrophenanthrene dimer linked to a bibenzyl or dihydrophenanthrene through a C-O-C bond (3 and4), and a pair of rare polymers with a bibenzyl connected to C-8' of the dihydrophenanthro[b]furan moiety via a methylene (5), together with four known compounds (6-9) were isolated from the tubers of Bletilla striata. Their structures including the absolute configurations were determined using spectroscopic data analysis and ECD and NMR calculations, combined with the exciton chirality method or the reversed helicity rule. The atropisomerism of dihydrophenanthrenes and related polymers was considered based on their chiral optical properties, and QM torsion profile calculations, which revealed the racemic mixture form of the polymers. Compounds 4, 5b, 6a and 7b significantly inhibited the production of NO in LPS-induced BV-2 cells, with IC₅₀ values ranging from 0.78 to 5.52 μM. Further mechanistic study revealed that 7b suppressed the expression of iNOS, and suppressed the phosphorylation of the p65 subunit to regulate the NF-κB signaling pathway. Furthermore, compounds 2b, 5a, 5b, 7a and 7b displayed significant protein tyrosine phosphatase 1B (PTP1B) inhibitory activities with IC₅₀ values of 3.43-12.30 μM.