Green synthesis of silver nanoparticles using Phlebopus portentosus polysaccharide and their antioxidant, antidiabetic, anticancer, and antimicrobial activities.

Silver nanoparticles (AgNPs) by green synthesis from fungi polysaccharides are attracting increasing attention owing to their distinctive features and special applications in numerous fields. In this study, a cost-effective and environmentally friendly biosynthesizing AgNPs method with no toxic chemicals involved from the fruiting body polysaccharide of Phlebopus portentosus (PPP) was established and optimized by single factor experiment and response surface methodology. The optimum synthesis conditions of polysaccharide-AgNPs (PPP-AgNPs) were identified to be the reaction time of 140 min, reaction temperature of 94 °C, and the PPP: AgNO3 ratio of 1:11.5. Formation of PPP-AgNPs was indicated by visual detection of colour change from yellowish to yellowish brown. PPP-AgNPs were characterized by different methods and further evaluated for biological activities. That the Ultraviolet-visible (UV-Vis.) spectroscopy displayed a sharp absorption peak at 420 nm confirmed the formation of AgNPs. Fourier transform infrared (FTIR) analysis detected the presence of various functional groups. The lattice indices of (111), (200), (220), and (331), which indicated a faced-centered-cubic of the Ag crystal structure of PPP-AgNPs, was confirmed by X-ray diffraction (XRD) and the particles were found to be spherical through high resolution transmission electron microscopy (HRTEM). Energy dispersive X-ray spectroscopy (EDS) determined the presence of silver in PPP-AgNPs. The percentage relative composition of elements was determined as silver (Ag) 82.5 % and oxygen (O) 17.5 % for PPP-AgNPs, and did not exhibit any nitrogen peaks. The specific surface area of PPP-AgNPs was calculated to be 0.5750 m2/g with an average pore size of 24.33 nm by BET analysis. The zeta potential was -4.32 mV, which confirmed the stability and an average particle size of 64.5 nm was calculated through dynamic light scattering (DLS). PPP-AgNPs exhibited significant free radical scavenging activity against DPPH with an IC50 value of 0.1082 mg/mL. The MIC values of PPP-AgNPs for E. coli, S. aureus, C. albicans, C. glabrata, and C. parapsilosis are 0.05 mg/mL. The IC50 value of the inhibition of PPP-AgNPs against α-glucosidase was 11.1 µg/mL, while the IC50 values of PPP-AgNPs against HepG2 and MDA-MB-231 cell lines were calculated to be 14.36 ± 0.43 µg/mL and 40.05 ± 2.71 µg/mL, respectively. According to the evaluation, it can be concluded that these green-synthesized and eco-friendly PPP-AgNPs are helpful to improve therapeutics because of significant antioxidant, antimicrobial, antidiabetic, and anticancer properties to provide new possibilities for clinic applications.

Global Profiling and Structural Characterization of Metabolites of Ononin Using HPLC-ESI-IT-TOF-MSn After Oral Administration to Rats.

Ononin is a bioactive isoflavone of legumes. To explore the "effective forms" of ononin, its metabolites were characterized using HPLC-ESI-IT-TOF-MSn after oral administration to rats. Metabolites (106), including 94 new metabolites, were characterized, which contained 17 phase I, 23 hydroxylated and methylated, 54 sulfated, 10 glucuronidated, and 2 sulfated and glucuronidated metabolites. Six hydroxylated metabolites of formononetin (aglycone of ononin) were simultaneously detected for the first time. Twenty-three hydroxylated and methylated metabolites were the new metabolites of ononin, and the number of hydroxylation and methylation was 1-3 and 1-2. Twenty metabolites have ononin-related bioactivities, and many metabolites have the same bioactivities. Their probable mechanisms of action may be additive and/or synergistic effects, especially because of the addition of the blood concentrations of these compounds. The results provide a foundation for a better understanding of the "effective forms" of ononin.

Exploring the In Vivo Existence Forms (23 Original Constituents and 147 Metabolites) of Astragali Radix Total Flavonoids and Their Distributions in Rats Using HPLC-DAD-ESI-IT-TOF-MSn.

Astragali Radix total flavonoids (ARTF) is one of the main bioactive components of Astragali Radix (AR), and has many pharmacological effects. However, its metabolism and effective forms remains unclear. The HPLC-DAD-ESI-IT-TOF-MSn technique was used to screen and tentatively identify the in vivo original constituents and metabolites of ARTF and to clarify their distribution in rats after oral administration. In addition, modern chromatographic methods were used to isolate the main metabolites from rat urine and NMR spectroscopy was used to elucidate their structures. As a result, 170 compounds (23 original constituents and 147 metabolites) were tentatively identified as forms existing in vivo, 13 of which have the same pharmacological effect with ARTF. Among 170 compounds, three were newly detected original constituents in vivo and 89 were new metabolites of ARTF, from which 12 metabolites were regarded as new compounds. Nineteen original constituents and 65 metabolites were detected in 10 organs. Four metabolites were isolated and identified from rat urine, including a new compound (calycoisn-3'-O-glucuronide methyl ester), a firstly-isolated metabolite (astraisoflavan-7-O-glucoside-2'-O-glucuronide), and two known metabolites (daidzein-7-O-sulfate and calycosin-3'-O-glucuronide). The original constituents and metabolites existing in vivo may be material basis for ARTF efficacy, and these findings are helpful for further clarifying the effective forms of ARTF.

Systematic screening and characterization of prototype constituents and metabolites of total astragalosides using HPLC-ESI-IT-TOF-MSn after oral administration to rats.

Astragalosides (AGs) are the main bioactive constituents in Astragali Radix (AR), and have a wide range of pharmacological properties, including immunoregulatory, cardioprotective, neuroprotective, antioxidative, antidiabetic, and antinociceptive effects. However, the metabolism of total AGs remains unclear. To clarify the metabolic fate of AGs after oral administration to rats, total AGs were isolated from AR extracts using AB-8 macroporous resin chromatography and preparative HPLC, and then analyzed using HPLC-DAD-ELSD and LC-MS. HPLC-ESI-IT-TOF-MSn was used to systematically screen and characterize prototype constituents and metabolites of total AGs in rat feces, urine, and plasma samples. As a result, 123 AG-related compounds from feces were detected and structurally characterized. Among the 123 compounds, 107 were phase I metabolites, of which 91 were new metabolites, and 73 were new compounds. In addition, six prototype constituents in urine, and one in plasma were detected. The main metabolic sites in the structure of cycloastragenol (CAG), the aglycone of AGs, were found to be the 9, 19-cyclopropane ring (E ring) and the 20, 24-furan ring (F ring). The cleavage mode of CAG derivatives in negative ion mode was identified, and was found to be highly dependent on the integrity of the E ring. Mono- to tetra-hydroxylated and carboxyl substituted metabolites were tentatively identified. Deglycosylation, hydroxylation, dehydrogenation, isomerization, ring cleavage, and carboxyl substitution were considered to be the major metabolic reactions involved in the formation of the metabolites, among which carboxyl substitution was a novel metabolic reaction. In summary, after total AGs were orally administered to rats, their constituents were extensively metabolized in a phase I manner, and the metabolites were excreted mainly into feces. To our knowledge, this is the first systematic study on the metabolism of total AGs. The results give us insight into the metabolic profiles of total AGs in vivo, and provide a foundation for identifying effective forms of AGs and exploring their mechanism in future studies.