Fascinating polyphenol lignin extracted from sawdust via a green and recyclable solvent route.

Due to the complexity, heterogeneity and recalcitrant structure of lignin, the extraction of multifunctional lignin directly from lignocellulose is still a challenge. Here, a green and recyclable route was proposed to separate high-quality lignin and tailor its functionalities. Through tuning the components of deep eutectic solvent (DES) and separation procedures, DES extracted lignin (DESL) exhibited high purity of 99.6 %, yield of 83.2 % and phenolic hydroxyl content of 8.33 wt%. The results of FTIR and 13C NMR demonstrated that DESL possessed more oxygen-containing reactive groups compared with commercial lignin (CL), enabling DESL with more superior functional activities. DESL exhibited higher antioxidant activity with the DPPH capture rate of 73.2 %. Meanwhile, DESL showed strong bactericidal effects against E. coli (100 %) and S. aureus (100 %) due to higher phenolic hydroxyl content, which could destroy bacterial cell membranes and inhibit bacterial metabolism by interacting with phospholipid layer and protein. Additionally, DESL displayed strong UV absorption and could be blended with polyurethane to enhance UV shielding property of polyurethane composite film with >50 of UPF value. In summary, DES treatment is a suitable strategy for high-quality lignin separation, which opens a broad spectrum of possibilities for lignin valorization.

Strong and flexible lignocellulosic film fabricated via a feasible molecular remodeling strategy.

Biomass-derived sustainable film is a promising alternative to synthetic plastic, but hampered by strength, toughness and flexibility trade-off predicament. Here, a feasible and scalable strategy was proposed to fabricate strong and flexible lignocellulosic film through molecular reconstruction of cellulose and lignin. In this strategy, polyphenol lignin was absorbed and wrapped on the surface of cellulose fiber, forming strong interfacial adhesion and cohesion via intramolecular and intermolecular hydrogen bonding. Further, covalent ether bond was generated between the hydroxyl groups of lignocellulose to form chemical cross-linking network induced by epichlorohydrin (ECH). The synergistic effect of hydrogen bonding and stable chemical cross-linking enabled the resultant lignocellulosic film (ELCF) with outstanding mechanical strength of 132.48 MPa, the elongation at break of 9.77 %, and toughness of 9.77 MJ·m-3. Notably, the integration of polyphenol lignin synergistically improved the thermal stability, water resistance, UV-blocking performances of ELCF. Importantly, after immersion for 30 d, ELCF still possessed high wet strength of 70.38 MPa, and elongation at break of 7.70 %, suggesting excellent and durable mechanical performances. Moreover, ELCF could be biodegraded in the natural soil. Therefore, this study provides a new and versatile approach to reconstruct highly-performance lignocellulosic films coupling strength, toughness with flexibility for promising plastic replacement.

Nanocellulose interface enhanced all-cellulose foam with controllable strength via a facile liquid phase exchange route.

The development of sustainable, biodegradable, non-toxic biomass foams with outstanding physical properties to replace traditional petroleum-based foams is urgent. In this work, we proposed a simple, efficient, and scalable approach to fabricate nanocellulose (NC) interface enhanced all-cellulose foam through ethanol liquid phase exchange and subsequent ambient drying. In this process, NCs served as reinforcer and binder were integrated with pulp fiber to improve cellulose interfibrillar bonding and interface adhesion between NCs and pulp microfibrils. The resultant all-cellulose foam displayed stable microcellular structure (porosity of 91.7-94.5 %), low apparent density (0.08-0.12 g/cm3), and high compression modulus (0.49-2.96 MPa) by regulating the content and size of NCs. Further, the strengthening mechanism of the structure and property of all-cellulose foam were investigated in detail. This proposed process enabled ambient drying, and is simple and feasible for low-cost, practicable, and scalable production of biodegradable, green bio-based foam without special apparatuses and other chemicals.

New Monoterpene-Conjugated Phenolic Constituents from Nutmeg and Their Autophagy Modulating Activities.

The seed of Myristica fragrans Houtt (nutmeg) is one of the important spices that have been extensively used in the culinary, food, beverage, and also in medicinal products industry. Previous phytochemical studies on nutmeg were mainly focused on lignans and neolignans. However, the other constituents have been poorly studied. In this study, 11 new monoterpene-conjugated phenolic derivatives, named myrifratins A-K (1-11), and five known compounds were isolated from nutmeg. The novel neolignan-diarylnonanoid-monoterpene conjugates (1 and 2) were first isolated in nature. Compounds 3-7 were rarely monoterpene-diarylnonanoid-conjugated derivatives, and 8-11 were the first examples of monoterpene-neolignan conjugates. Compounds 4-6, 12, and 13 showed potent autophagy inhibitory activities in a concentration-dependent manner. Our findings showed an uncommon class of monoterpene-conjugated phenolic derivatives in nature and reported their autophagy inhibition activities for the first time, which may give a new insight into the benefits or safety of nutmeg in foods.

Chlorfortunones A and B, Two Sesquiterpenoid Dimers, Possessing Dispiro[4,2,5,2]pentadecane-6,10,14-tren Moiety from Chloranthus fortunei.

Chlorfortunones A (1) and B (2), two novel sesquiterpenoid dimers, were isolated from the roots of Chloranthus fortunei. Their structures were elucidated by spectroscopic analysis and X-ray diffraction analysis. Compounds 1 and 2 represent a new type of sesquiterpenoid dimer possessing an unprecedented 3/5/6/6/6/5 hexacyclic system with a unique dispiro[4,2,5,2]pentadecane-6,10,14-trien moiety. A plausible biosynthetic pathway of 1 and 2 was proposed. Compound 1 showed transforming growth factor (TGF)-ß inhibitory activity in MDA-MB-231 cells.

Linderanoids A-O, dimeric sesquiterpenoids from the roots of Lindera aggregata (Sims) Kosterm.

Fifteen undescribed dimeric sesquiterpenoids, linderanoids A-O along with one known lindenane-type sesquiterpenoid dimer, lindenaneolide F, were isolated and identified from the roots of Lindera aggregata. Their structures and absolute configurations were elucidated using spectroscopy and electronic circular dichroism (ECD) analysis. All the isolated compounds were screened for transforming growth factor (TGF)-ß inhibitory activity, and the results showed that linderanoid E significantly inhibited the TGF- ß induced smad2 phosphorylation at a concentration of 25 µM.