Equilibrium, kinetics and thermodynamics of Cu(II) biosorption on Chinese chestnut shell pretreated with steam explosion.

The shells of Chinese chestnuts (Castanea mollissima) are an agricultural residue. This work aimed to evaluate this feasibility of using steam explosion to modify this residue for Cu(II) biosorption from aqueous solutions. Equilibrium, kinetic and thermodynamic parameters were evaluated. The steam-explosion pretreatment increased the surface area of the chestnut shell and exposed more hydroxyl and carboxyl groups, which are binding sites for Cu(II). It changed the sorption from a spontaneous process driven by enthalpy to a nonspontaneous one driven by entropy. It increased the Cu(II) sorption capacity at higher temperatures while it decreased the capacity at lower ones. Compared with untreated chestnut shell, the steam-exploded shell is preferable for Cu(II) sorption at higher temperatures.

Comparison of Antioxidant Activities of Melanin Fractions from Chestnut Shell.

Chestnut shell melanin can be used as a colorant and antioxidant, and fractionated into three fractions (Fr. 1, Fr. 2, and Fr. 3) with different physicochemical properties. Antioxidant activities of the fractions were comparatively evaluated for the first time. The fractions exhibited different antioxidative potential in different evaluation systems. Fr. 1, which is only soluble in alkaline water, had the strongest peroxidation inhibition and superoxide anion scavenging activity; Fr. 2, which is soluble in alkaline water and hydrophilic organic solvents but insoluble in neutral and acidic water, had the greatest power to chelate ferrous ions; and Fr. 3, which is soluble both in hydrophilic organic solvents and in water at any pH conditions, had the greatest hydroxyl (·OH) and 1,1-diphenyl-2-picryl-hydrazyl (DPPH·) radicals scavenging abilities, reducing power, and phenolic content. The pigment fractions were superior to butylated hydroxytolune (BHT) in ·OH and DPPH· scavenging and to ethylene diamine tetraacetic acid (EDTA) in the Fe(2+)-chelation. They were inferior to BHT in peroxidation inhibition and O2·(-) scavenging and reducing power. However, BHT is a synthetic antioxidant and cannot play the colorant role. The melanin fractions might be used as effective biological antioxidant colorants.

Insolubilization of Chestnut Shell Pigment for Cu(II) Adsorption from Water.

Chestnut shell pigment (CSP) is melanin from an agricultural waste. It has potential as an adsorbent for wastewater treatment but cannot be used in its original state because of its solubility in water. We developed a new method to convert CSP to insolubilized chestnut shell pigment (ICSP) by heating, and the Cu(II) adsorption performance of ICSP was evaluated. The conversion was characterized, and the thermal treatment caused dehydration and loss of carboxyl groups and aliphatic structures in CSP. The kinetic adsorption behavior obeyed the pseudo-second-order rate law, and the equilibrium adsorption data were well described with both the Langmuir and the Freundlich isotherms. ICSP can be used as a renewable, readily-available, easily-producible, environmentally-friendly, inexpensive and effective adsorbent to remove heavy-metal from aquatic environments.

Mechanism of Electroacupuncture Against Cerebral Ischemia-Reperfusion Injury: Reducing Inflammatory Response and Cell Pyroptosis by Inhibiting NLRP3 and Caspase-1.

Cell pyroptosis is one of the main forms of neuronal injury after cerebral ischemia-reperfusion. It is accompanied by an inflammatory reaction and regulated by the caspase gene family. Electroacupuncture (EA) can reduce neuronal injury caused by cerebral ischemia-reperfusion, and we speculated that EA can prevent neuronal pyroptosis after cerebral ischemia-reperfusion by regulating the nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3)/caspase-1 pathway. The cerebral ischemia-reperfusion injury model of C57 and caspase-1 gene knockout (Cas-1 ko) mice was established by Longa's method. EA was conducted at acupoints Chize (LU5), Hegu (LI4), Sanyinjiao (SP6), and Zusanli (ST36) for 1.5 h after cerebral ischemia-reperfusion injury for 20 min, and observation was carried out after 24 h. Neurological deficit scores evaluated the neurological function, cerebral infarction volume was observed by triphenyl tetrazolium chloride (TTC) staining, hematoxylin and eosin (H&E) staining, TUNEL and caspase-1 double-labeled fluorescence staining, and NLRP3 and caspase-1 double-labeled immunofluorescence staining that were used to observe the morphology of neurons in hippocampus, and the protein expression of NLRP3, pro-caspase-1, cleaved caspase-1 p20, pro-interleukin-1ß (IL-1ß), cleaved IL-1ß, and GSDMD was detected by Western blot assay. Results showed that EA could reduce the score of neurological deficit, reduce the volume of cerebral infarction and improve the degree of nerve cell injury, and inhibit NLRP3, pro-caspase-1, cleaved caspase-1 p20, pro-IL-1ß, cleaved IL-1ß, and GSDMD protein expression. In summary, EA plays a neuroprotective role by reducing the pyroptotic neurons that were caspase 1-mediated and inflammatory response after cerebral ischemia-reperfusion.

Four new chemical constituents from Piper pleiocarpum.

Two new polyoxygenated cyclohexenes (1-2), one new benzoate derivative (3), and one new dineolignan (4) together with one known neolignan (5) were isolated from whole plants of Piper pleiocarpum. The structures of these compounds were determined by extensive spectroscopic methods including 1D, 2D NMR, HR-ESI-MS, and by comparison with the literature. The 13C NMR spectra of the known compound 5 were completely assigned for the first time. All isolated compounds (1-5) were evaluated for their cytotoxic activities against five human cancer cell lines (including A-549, SMMC-7721, HL-60, MCF-7, and SW-480), Only compound 4 showed inhibitory activity against MCF-7 cell line with IC50 value of 18.24 ± 0.69 µM.

Histological observation of somatic embryogenesis from cultured embryos of Quercus variabilis Bl.

Immature zygotic embryos of Quercus variabilis Bl. were excised and cultured on MS basal medium containing 0.25 mg/L 2,4-dichlorophenoxyacetic acid and 0.5 mg/L 6-benzyl aminopurine. Callus was initiated from these embryos within 6 weeks. Two types of embryogenic calluses were formed: one was the white mucilaginous callus and the other was light yellow to translucent, glossy, mucilaginous. Histological examination showed that the non-embryogenic cells derived from zygotic embryos were large in size, with small nuclei, thin cytoplasm, and the embryogenic cells were small in size, with large nuclei, thick cytoplasm and denser arrangement. Somatic embryos were induced from embryogenic masses (EMS) cultured on a medium not containing plant growth regulators (PGRs). The histological origin of somatic embryos was single epidermal or subepidermal cells. Somatic embryos displayed a standard development pattern, from globular ones to heart-like and torpedo-shaped ones and finally to embryo with two cotyledons, which was similar to the development of zygotic embryo in vivo. Secondary proembryos were formed on the axis and cotyledon of existing embryos and originated from single, densely stained cells of the epidermis at all stages.