Characterization of lignin streams during ionic liquid/hydrochloric acid/formaldehyde pretreatment of corn stalk.

This work investigated the role of formaldehyde (FA) in lignin anti-condensation during corn stalk pretreatment based on 1-butyl-3-methylimidazolium chloride ([C4C1im]Cl)/hydrochloric acid (HCl). As a result of the aldolization reactions between FA and lignin, the condensation of lignin fragments was inhibited, and lignin remained in soluble fragmental molecules. Characterizations on the compositional and structural changes of lignin and its degraded products during pretreatment (80 °C-100 °C, 2-5 h) with FA addition in comparison with those in DO/HCl/FA or [C4C1im]Cl/HCl were conducted. Results revealed that the structural features of lignin were affected by FA addition and solvent type. In the [C4C1im]Cl/HCl/FA system, FA stabilization was unfavorable for the cleavage of ß-O-4' bonds and lignin with low S/G ratio (3.4) and high molecular weight (Mw = 9920 g·mol-1) was extracted. The compositions of degraded products were considerably affected by FA addition.

Yiqihuoxuejiedu formula inhibits vascular remodeling by reducing proliferation and secretion of adventitial fibroblast after balloon injury.

Vascular remodeling occurs in atherosclerosis, hypertension, and restenosis after percutaneous coronary intervention. Adventitial remodeling may be a potential therapeutic target. Yiqihuoxuejiedu formula uses therapeutic principles from Chinese medicine to supplement Qi, activate blood circulation, and resolve toxin and it has been shown to inhibit vascular stenosis. To investigate effects and mechanisms of the formula on inhibiting vascular remodeling, especially adventitial remodeling, rats with a balloon injury to their common carotid artery were used and were treated for 7 or 28 days after injury. The adventitial area and α -SMA expression increased at 7 days after injury, which indicated activation and proliferation of adventitial fibroblasts. Yiqihuoxuejiedu formula reduced the adventitial areas at 7 days, attenuated the neointima and vessel wall area, stenosis percent, and α -SMA expression in the neointima, and reduced collagen content and type I/III collagen ratio in the adventitia at 28 days. Yiqihuoxuejiedu formula had more positive effects than Captopril in reducing intimal proliferation and diminishing stenosis, although Captopril lowered neointimal α -SMA expression and reduced the collagen content at 28 days. Yiqihuoxuejiedu formula has inhibitory effects on positive and negative remodeling by reducing adventitial and neointimal proliferation, reducing content, and elevating adventitial compliance.