Lignin as a Novel Tyrosinase Inhibitor: Effects of Sources and Isolation Processes

Lignin is the most abundant aromatic biopolymer in nature and its value-added application has attracted great attention. In this work, the inhibitory effect and mechanism of lignin on tyrosinase activity were investigated to develop lignin as a novel tyrosinase inhibitor. Six lignin samples isolated by alkali and ethanol organosolv processes from three typical lignocellulosic feedstocks were used to evaluate the effects of the lignin sources and isolation processes on the antityrosinase activity. The lignin heterogeneity including purity, molecular weight, and chemical structure was characterized detailedly by component determination, GPC, FTIR, 2D NMR, and Py-GCMS analyses. The enzyme studies showed that inhibitory activities of ethanol organosolv lignins were obviously stronger than those of alkali lignins. For lignins from different sources, corn stalk lignin (gramineae organosolv lignin, GOL) presented highest inhibitory effect with an IC₅₀ value of 0.276 mg/mL, which was comparable to that of positive control <i>p</i>-hydroxy benzaldehyde (0.233 mg/mL). The inhibitory kinetics suggested that the ethanol organosolv lignin from corn stalk was a reversible mixed-type inhibitor. The fluorescence quenching studies demonstrated that the interaction of GOL with the enzyme was a significant molecular mechanism to inhibit the enzymatic activity. Consequently, these results suggest that lignin possesses antityrosinase activity and can be potentially used as an enzyme inhibitor in overtyrosinase activity control fields

Data_Sheet_1_The Relationship Between Successful Aging and All-Cause Mortality Risk in Older Adults: A Systematic Review and Meta-Analysis of Cohort Studies.DOC

BackgroundThis meta-analysis aimed to explore the effect of successful aging (SA) on all-cause mortality risk in older people to provide a theoretical basis for promoting SA.MethodsPubMed, Embase, CINAHL, CNKI, and WanFang databases (inception to March 4, 2021) were searched for cohort studies to evaluate the relationship between SA and mortality in older people. A random-effects model was used to synthesis hazard ratio and 95% confidence intervals. Quality assessment was performed using the Newcastle–Ottawa scale. All statistical analyses were conducted in STATA 16.0.ResultsIn total, 21,158 older adults from 10 studies were included in the current systematic review and meta-analysis. The SA group tended to have 50% lower risk of all-cause mortality than the non-SA group (pooled hazard ratio = 0.50, 95% confidence intervals: 0.35–0.65, P 2 = 58.3%). The risk of all-cause mortality in older people increased by 17% for each unit increment in the healthy aging index (HAI) (I2 = 0%, P = 0.964). Compared with the reference group (HAI 0-2), older people with HAI 3-4, HAI 5-6, and HAI 7-10 had 1.31-fold, 1.73-fold, and 2.58-fold greater risk of all-cause mortality, respectively. Subgroup analysis did not reveal possible sources of heterogeneity.ConclusionsThis meta-analysis suggests that older adults with SA reduced the risk of all-cause mortality by 50%. However, few interventional studies have been conducted. Therefore, healthcare providers must be aware of the relationship between SA and mortality risk and actively develop intervention methods for helping old people achieve SA.</p

Role of NK-1 receptor in the anti-apoptotic effects of SP.

<p>Mouse corneal epithelial cells were treated with 1 μM NK-1 receptor antagonist L-733,060 with 1 μM SP 2 h before the addition of glucose for 24 h. The phosphorylation of Akt was evaluated by Immunofluorescence staining or Western blot (A). The apoptosis was evaluated by FACS analysis followed by FITC-Annexin V/PI staining (B), and the detection of Bad, Bax, AIF, Ca²⁺ and mitochondrial membrane potential (C). The intracellular ROS and glutathione (GSH) were detected by staining with the fluorescence probes (D) and measured by the fluorescence intensity (E). The cellular total antioxidant capacity (TAC) was measured by the ABTS assay (E).</p

SP reactivates the phosphorylation of Akt and recovers the redox balance of corneal epithelial cells impaired by hyperosmotic stress.

<p>Mouse corneal epithelial cells were treated with 550 mOsm hyperosmotic stress by addition of glucose with or without 1 μM SP for 24 h. The phosphorylation of Akt was evaluated by Immunofluorescence staining or Western blot (A). The intracellular ROS and glutathione (GSH) levels were detected by staining with the fluorescence probes (B) and measured by the fluorescence intensity (C). The cellular total antioxidant capacity (TAC) was measured by the ABTS assay (C).</p

Role of Akt reactivation in the anti-apoptotic effects of SP.

<p>Mouse corneal epithelial cells were treated with 40 μM Akt inhibitor V and 1 μM SP 2 h before the addition of glucose for 24 h. The phosphorylation of Akt was evaluated by Immunofluorescence staining or Western blot (A). The apoptosis was evaluated by FACS analysis followed by FITC-Annexin V/PI staining (B), and the detection of Bad, Bax, AIF, Ca²⁺ and mitochondrial membrane potential (C). The intracellular ROS and glutathione (GSH) were detected by staining with the fluorescence probes (D) and measured by the fluorescence intensity (E). The cellular total antioxidant capacity (TAC) was measured by the ABTS assay (E).</p

Novel Surfactant-Assisted Hydrothermal Fabrication of a Lignin Microsphere as a Green Reducer and Carrier for Pd Nanoparticles

The development and application of lignin materials with regular nano/microstructures have attracted great interest, as they offer emerging valorization of this currently underused biopolymer. In this work, we propose a novel surfactant-assisted hydrothermal strategy for fabrication of a lignin microsphere (LMS), avoiding the usage of high quantities of costly and environmentally problematic organic solvents in conventional methods. The as-prepared LMS was then applied as a green reducer and carrier for the synthesis of Pd nanoparticles (NPs) that were employed to catalyze hydrogen evolution from formic acid. Under hydrothermal treatment at 180 °C, LMS was formed from irregular bulk lignin particles in only 20 min. However, some irregular particles with large sizes (over 600 nm) were observed even under optimized hydrothermal conditions. Therefore, surfactant poly­(vinylpyrrolidone) (PVP) was added to improve the size uniformity and spherical morphology of the LMS, thus obtaining LMS with narrow size distribution (100–500 nm) and a regular spherical morphology. Interestingly, the addition of PVP further promoted the dispersion of Pd NPs on LMS and decreased the Pd NP size. Hence, Pd@LMS-P (PVP added) presented substantially improved activity than Pd@LMS-0 (PVP free), and both catalysts exhibited significantly enhanced activity compared with bare Pd NPs. Consequently, this work demonstrates that the proposed surfactant-assisted hydrothermal method is feasible to prepare well-defined LMS and further contributes to the green formation of Pd NPs with reduced particle size and improved catalytic activity

Data_Sheet_2_The Relationship Between Successful Aging and All-Cause Mortality Risk in Older Adults: A Systematic Review and Meta-Analysis of Cohort Studies.DOCX

BackgroundThis meta-analysis aimed to explore the effect of successful aging (SA) on all-cause mortality risk in older people to provide a theoretical basis for promoting SA.MethodsPubMed, Embase, CINAHL, CNKI, and WanFang databases (inception to March 4, 2021) were searched for cohort studies to evaluate the relationship between SA and mortality in older people. A random-effects model was used to synthesis hazard ratio and 95% confidence intervals. Quality assessment was performed using the Newcastle–Ottawa scale. All statistical analyses were conducted in STATA 16.0.ResultsIn total, 21,158 older adults from 10 studies were included in the current systematic review and meta-analysis. The SA group tended to have 50% lower risk of all-cause mortality than the non-SA group (pooled hazard ratio = 0.50, 95% confidence intervals: 0.35–0.65, P 2 = 58.3%). The risk of all-cause mortality in older people increased by 17% for each unit increment in the healthy aging index (HAI) (I2 = 0%, P = 0.964). Compared with the reference group (HAI 0-2), older people with HAI 3-4, HAI 5-6, and HAI 7-10 had 1.31-fold, 1.73-fold, and 2.58-fold greater risk of all-cause mortality, respectively. Subgroup analysis did not reveal possible sources of heterogeneity.ConclusionsThis meta-analysis suggests that older adults with SA reduced the risk of all-cause mortality by 50%. However, few interventional studies have been conducted. Therefore, healthcare providers must be aware of the relationship between SA and mortality risk and actively develop intervention methods for helping old people achieve SA.</p

SP protects from hyperosmotic stress-induced apoptosis of corneal epithelial cells.

<p>Mouse corneal epithelial cells were treated with 550 mOsm hyperosmotic stress by addition of glucose with or without 0.1, 1 or 10 μM SP for 24 h. Cell morphology was observed under inverted contrast microscopy (A). The apoptosis was evaluated by FACS analysis followed by FITC-Annexin V/PI staining (B), caspase activity measurement (C), and the detection of Bcl-2-associated death promoter (Bad), BCL2-associated X protein (Bax), apoptosis inducing factor (AIF), Ca²⁺ and mitochondrial membrane potential (JC-1 staining) (D).</p

Role of redox regulation in the anti-apoptotic effects of SP.

<p>Mouse corneal epithelial cells were treated with 100 μM L-BSO and 1 μM SP 2 h before the addition of glucose for 24 h. The phosphorylation of Akt was evaluated by Immunofluorescence staining or Western blot (A). The apoptosis was evaluated by FACS analysis followed by FITC-Annexin V/PI staining (B), and the detection of Bad, Bax, AIF, Ca²⁺ and mitochondrial membrane potential (C). The intracellular ROS and glutathione (GSH) were detected by staining with the fluorescence probes (D) and measured by the fluorescence intensity (E). The cellular total antioxidant capacity (TAC) was measured by the ABTS assay (E).</p

Hyperosmotic stress induces a dose- and time-dependent apoptosis in mouse corneal epithelial cells.

<p>Mouse corneal epithelial cells were treated with varying osmolarities (450, 550 or 650 mOsm) by addition of glucose for 24 h. The apoptotic cells were observed under inverted contrast microscopy (A) and detected by staining with FITC-Annexin V/PI and FACS analysis (B). Mouse corneal epithelial cells were treated with 550 mOsm hyperosmotic stress by addition of glucose for 12, 24 or 48h, and the apoptotic cells were investigated by staining with FITC-Annexin V/PI and FACS analysis (C). Hyperosmotic stress treatment induced the apoptosis of mouse corneal epithelial cells in a dose and time-dependent manner (B, C).</p