Neither the routes through which humin byproducts are formed, nor their molecular structure have yet been unequivocally established. A better understanding of the formation and physicochemical properties of humins, however, would aid in making biomass conversion processes more efficient. Here, an extensive multiple-technique-based study of the formation, molecular structure, and morphology of humins is presented as a function of sugar feed, the presence of additives (e.g., 1,2,4-trihydroxybenzene), and the applied processing conditions. Elemental analyses indicate that humins are formed through a dehydration pathway, with humin formation and levulinic acid yields strongly depending on the processing parameters. The addition of implied intermediates to the feedstocks showed that furan and phenol compounds formed during the acid-catalyzed dehydration of sugars are indeed included in the humin structure. IR spectra, sheared sum projections of solid-state 2DPASS (13) C NMR spectra, and pyrolysis GC-MS data indicate that humins consist of a furan-rich polymer network containing different oxygen functional groups. The structure is furthermore found to strongly depend on the type of feedstock. A model for the molecular structure of humins is proposed based on the data presented.

Acortatarins A (1) and B (2), two novel spiroalkaloids with a naturally unusual morpholine motif, were isolated from the rhizome of Acorus tatarinowii. Their structures with absolute configuration were determined by spectroscopic methods, X-ray diffraction analysis, and Mosher's method. Importantly, compound 1 could significantly inhibit reactive oxygen species production in high-glucose-stimulated mesangial cells in a dose- and time-dependent manner.

Ten new phenolic compounds including the six neolignans 1 -3 and 6 -8 and four caffeoyl derivatives, i.e., myo-inositol 1-caffeate (9), myo-inositol 6-caffeate (10), myo-inositol 5-caffeate (11), and paucine 3'-b-d-glucopyranoside (12) were isolated from the whole plants of Selaginella moellendorffii (caffeic acid ¼ 3-(3,4-dihydroxyphenyl)prop-2-enoic acid). Their structures were established by spectroscopic and chemical methods.Introduction. -Selaginella moellendorffii Hieron. (Selaginellaceae), a perennial herb, is mainly distributed in the southern area of the Changjiang River in China and has been used to treat jaundice, gonorrhea, bleeding, acute hepatitis, and idiopathic thrombocytopenic purpura (ITP) [5] biflavones in this plant. In our recent research, a series of pyrrolidinoindoline alkaloids were found from this plant [6]. In continuation of the studies on this plant, ten new phenolic derivatives, 1 -3 and 6 -12, and four known ones, compounds 4 and 5, paucine (¼ (2E)-N-(4-aminobutyl)-3-(3,4-dihydroxyphenyl)prop-2-enamide 13) [7], and N