Biflavonoids from Selaginella doederleinii as Potential Antitumor Agents for Intervention of Non-Small Cell Lung Cancer

Two new chromone derivatives from the rhizosphere soil fungus Ilyonectria robusta

Two new chromone derivatives (1 and 2), and two known compounds (3 and 4) were isolated from the rhizosphere soil fungus Ilyonectria robusta. Their planar structures and absolute configurations were determined by extensive spectroscopic analysis and electronic circular dichroism (ECD) calculations. Additionally, all the isolated compounds were evaluated for their antibacterial activity against Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa and Escherichia coli, but no obvious activity was observed at a concentration of 128 μg/mL.

Advances in the Anti-Tumor Activity of Biflavonoids in Selaginella

Despite the many strategies employed to slow the spread of cancer, the development of new anti-tumor drugs and the minimization of side effects have been major research hotspots in the anti-tumor field. Natural drugs are a huge treasure trove of drug development, and they have been widely used in the clinic as anti-tumor drugs. Selaginella species in the family Selaginellaceae are widely distributed worldwide, and they have been well-documented in clinical practice for the prevention and treatment of cancer. Biflavonoids are the main active ingredients in Selaginella, and they have good biological and anti-tumor activities, which warrant extensive research. The promise of biflavonoids from Selaginella (SFB) in the field of cancer therapy is being realized thanks to new research that offers insights into the multi-targeting therapeutic mechanisms and key signaling pathways. The pharmacological effects of SFB against various cancers in vitro and in vivo are reviewed in this review. In addition, the types and characteristics of biflavonoid structures are described in detail; we also provide a brief summary of the efforts to develop drug delivery systems or combinations to enhance the bioavailability of SFB monomers. In conclusion, SFB species have great potential to be developed as adjuvant or even primary therapeutic agents for cancer, with promising applications.

A novel biflavone from Reineckia carnea induces apoptosis of human renal cancer 786-O cells

Renal cell carcinoma (RCC) is a common malignant tumor of the urinary system, which is highly invasive, metastatic, and insensitive to radiotherapy and chemotherapy. Chinese herbal medicine has always been an important source of anti-tumor drug development. Reineckia carnea Kunth is a traditional herb commonly used by the Miao nationality in southwest China. In this study, the extract of Reineckia carnea was isolated and purified by reverse phase preparative chromatography and other chromatographic techniques. According to the physicochemical properties and spectral data, the structure of the compound was identified, and a novel biflavone compound named Reineckia-biflavone A (RFA) was obtained. The result of antiproliferative activity showed that RFA had cytotoxicity on 786-O cells with an IC50 value of 19.34 μmol/L. The results of CCK-8 and hemolysis assays showed that RFA was not significantly cytotoxic to both red blood cells (RBC) and peripheral blood mononuclear cells (PBMC). By Hoechst 33258 apoptosis staining, typical apoptotic morphology was observed under fluorescence microscope. RFA could induce the apoptosis of 786-O cells with the increase of apoptosis rate. The cell cycle tests showed that the cell proportion was obviously arrested in the S phase. At the same time, RFA could decrease the mitochondrial membrane potential and increase the intracellular free Ca2+ concentration. Western blot showed that the expression levels of pro-apoptotic proteins (Bax, Caspase-3, Cleaved Caspase-3, and Cytochrome c) in cells rose, while the expression level of anti-apoptotic proteins (Bcl-2) declined significantly. In conclusion, this study suggests that the RFA is a new biflavone determined by SciFinder retrieval. The apoptosis may be triggered by RFA through the mitochondrial pathway, which is mediated by up-regulating the intracellular calcium ion, down-regulating the mitochondrial membrane potential, and changing the apoptosis-related proteins.

Tissue Distribution, Excretion, and Interaction With Human Serum Albumin of Total Bioflavonoid Extract From Selaginella doederleinii

Selaginella doederleinii Hieron is a traditional Chinese medicinal herb widely used to treat different cancers. Previously, we showed that the total bioflavonoid extract of S. doederleinii (TBESD) exhibits anti-carcinogenic activities both in vitro and in vivo. However, the plasma protein binding and pharmacokinetics parameters of TBESD remain unclear. To investigate plasma protein binding, tissue distribution, and excretion of TBESD, rats were administered a single dose of TBESD (600 mg/kg) intragastrically and tissue distribution and excretion of TBESD components were determined by rapid high-performance liquid chromatography and tandem mass spectrometry. TBESD binding to human serum albumin (HSA) was assessed by fluorescence spectroscopy. TBESD components amentoflavone, delicaflavone, robustaflavone, 2″,3″-dihydro-3',3‴-biapigenin, and 3',3‴-binaringenin were rapidly absorbed and distributed in various tissues, mostly in the lungs, kidneys, and ovaries, without long-term accumulation. The excretion of bioflavonoids occurred mostly via the intestinal tract and constituted 30% of the administered dose up to 48 h. Spectral analysis indicated that TBESD had a dynamic quenching effect on HSA by binding to one HSA site through hydrophobic interactions and hydrogen bond formation. This is the first comprehensive report on the tissue distribution, excretion, and plasma protein binding of TBESD. This study provides important information on TBESD pharmacokinetics necessary for its further development into a therapeutic form for clinical applications.

Selaginellin Inhibits Melanogenesis via the MAPK Signaling Pathway

Hyperpigmented skin diseases such as melasma, freckles, and melanosis usually mar the appearance of patients. Traditional herbal medicines are highly accepted in inhibiting skin pigmentation, with advantages of high efficiency, low cost, and low side effects. Selaginellin (SEL), one of the active compounds of selaginella, has been proved to be exhibit antineoplastic, antioxidant, antisenescence, and antiapoptosis activities. In this study, we found that SEL can inhibit melanogenesis in vitro and in vivo. A mechanism study found that SEL inhibits melanogenesis through inhibiting the mitogen-activated protein kinase (MAPK) signaling pathway, then down-regulating the expression of microphthalmia-associated transcription factor (MITF) and downstream genes tyrosinase (TYR) and tyrosinase-related protein 2 (TYRP2). UVB-activated paracrine function of fibroblasts and keratinocytes promotes melanogenesis of melanocytes. Interestingly, SEL antagonizes UVB-activated paracrine function of fibroblasts and keratinocytes. These findings indicate that SEL can be a potential whitening compound to inhibit melanogenesis.

Green Extraction of Bioactive Compounds from Plant Biomass and Their Application in Meat as Natural Antioxidant

Plant extracts are rich in various bioactive compounds exerting antioxidants effects, such as phenolics, catechins, flavonoids, quercetin, anthocyanin, tocopherol, rutin, chlorogenic acid, lycopene, caffeic acid, ferulic acid, p-coumaric acid, vitamin C, protocatechuic acid, vitamin E, carotenoids, β-carotene, myricetin, kaempferol, carnosine, zeaxanthin, sesamol, rosmarinic acid, carnosic acid, and carnosol. The extraction processing protocols such as solvent, time, temperature, and plant powder should be optimized to obtain the optimum yield with the maximum concentration of active ingredients. The application of novel green extraction technologies has improved extraction yields with a high concentration of active compounds, heat-labile compounds at a lower environmental cost, in a short duration, and with efficient utilization of the solvent. The application of various combinations of extraction technologies has proved to exert a synergistic effect or to act as an adjunct. There is a need for proper identification, segregation, and purification of the active ingredients in plant extracts for their efficient utilization in the meat industry, as natural antioxidants. The present review has critically analyzed the conventional and green extraction technologies in extracting bioactive compounds from plant biomass and their utilization in meat as natural antioxidants.