Major lignans of sesame sesamin and sesamolin are benzodioxol--substituted furofurans. Sesamol, sesaminol, its epimers, and episesamin are transformation products found in processed products. Synthetic routes to all lignans are known but only sesamol is synthesized industrially. Biosynthesis of furofuran lignans begins with the dimerization of coniferyl alcohol, followed by the formation of dioxoles, oxidation, and glycosylation. Most genes of the lignan pathway in sesame have been identified but the inheritance of lignan content is poorly understood. Health-promoting properties make lignans attractive components of functional food. Lignans enhance the efficiency of insecticides and possess antifeedant activity, but their biological function in plants remains hypothetical. In this work, extensive literature including historical texts is reviewed, controversial issues are critically examined, and errors perpetuated in literature are corrected. The following aspects are covered: chemical properties and transformations of lignans; analysis, purification, and total synthesis; occurrence in Seseamum indicum and related plants; biosynthesis and genetics; biological activities; health-promoting properties; and biological functions. Finally, the improvement of lignan content in sesame seeds by breeding and biotechnology and the potential of hairy roots for manufacturing lignans in vitro are outlined.

Lignans of Sesame (Sesamum indicum L.): A Comprehensive Review.

Selenium compounds are pivotal in medicinal chemistry for their antitumoral and antioxidant properties. Forty seven acylselenoureas have been designed and synthesized following a fragment-based approach. Different scaffolds, including carbo- and hetero-cycles, along with mono- and bi-cyclic moieties, have been linked to the selenium containing skeleton. The dose- and time-dependent radical scavenging activity for all of the compounds were assessed using the in vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assays. Some of them showed a greater radical scavenging capacity at low doses and shorter times than ascorbic acid. Therefore, four compounds were evaluated to test their protective effects against H2O2-induced oxidative stress. One derivative protected cells against H2O2-induced damage, increasing cell survival by up to 3.6-fold. Additionally, in vitro cytotoxic activity of all compounds was screened against several cancer cells. Eight compounds were selected to determine their half maximal inhibitory concentration (IC50) values towards breast and lung cancer cells, along with their selectivity indexes. The breast cancer cells turned out to be much more sensitive than the lung. Two compounds (5d and 10a) stood out with IC50 values between 4.2 μM and 8.0 μM towards MCF-7 and T47D cells, with selectivity indexes greater than 22.9. In addition, compound 10b exhibited dual antioxidant and cytotoxic activities. Although further evidence is needed, the acylselenourea scaffold could be a feasible frame to develop new dual agents.

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Novel N,N'-Disubstituted Acylselenoureas as Potential Antioxidant and Cytotoxic Agents.

Lignans with α-glucosidase, protein tyrosine phosphatase 1B, and aldose reductase inhibitory activities from the fruits of Viburnum cylindricum

Phenylpropanoid and dibenzofuran derivatives from Crataegus pinnatifida with antiproliferative activities on hepatoma cells.

Thermal response of a protein (CoVE) conformation is studied by a coarse-grained Monte Carlo simulation. Three distinct segments, the N-terminal, Trans-membrane, and C-terminal are verified from its specific contact profile. The radius of gyration (Rg) is found to exhibit a non-monotonic sub-universal thermal response: Rg decays on heating in native phase (low-temperature regime) in contrast to a continuous increase on further raising the temperature before its saturation to a random-coil in denature phase. The globularity index (a measure of effective dimension) of the protein decreases as the protein denatures from a globular to a random-coil conformation.

Thermal denaturation of a protein (CoVE) by a coarse-grained Monte Carlo simulation

Furofuran lignans as a new series of antidiabetic agents exerting α-glucosidase inhibition and radical scarvenging: Semisynthesis, kinetic study and molecular modeling.

Thermally induced structural organization of nanodiscs by coarse-grained molecular dynamics simulations.

Using a coarse-grained model, self-organized assembly of proteins (e.g., CorA and its inner segment iCorA) is studied by examining quantities such as contact profile, radius of gyration, and structure factor as a function of protein concentration at a range of low (native phase) to high (denature phase) temperatures. Visual inspections show distinct structures, i.e., isolated globular bundles to entangled network on multiple length scales in dilute to crowded protein concentrations. In native phase, the radius of gyration of the protein does not vary much with the protein concentration while that of its inner segment increases systematically. In contrast, the radius of gyration of the protein shows enormous growth with the concentration due to entanglement while that of the inner segment remains almost constant in denatured phase. The multi-scale morphology of the collective assembly is quantified by estimating the effective dimension D of protein from scaling of the structure factor: collective assembly from inner segments remains globular (D~3) at almost all length scales in its native phase while that from protein chains shows sparsely distributed morphology with D ≤ 2 in entire temperature range due to entanglement except in crowded environment at low temperature where D~2.6. Higher morphological response of chains with only the inner-segments due to selective interactions in its native phase may be more conducive to self-organizing mechanism than that of the remaining segments of the protein chains.

Globular bundles and entangled network of proteins (CorA) by a coarse-grained Monte Carlo simulation

Rhipicephalus (Boophilus) microplus is tick parasite that affects the cattle industry worldwide. In R. (B.) microplus, acaricide resistance develops rapidly against many commercial acaricides. One of main resistance strategies is to enhance the metabolic detoxification mediated by R. (B.) microplus glutathione-S-transferase (RmGST). RmGST detoxifies acaricides by catalyzing the conjugation of glutathione to acaricides. Although structural and dynamic details of RmGST are expected to elucidate the biologic activity of this molecule, these data have not been available to date. Thus, Molecular Dynamics simulations were employed to study ligand-free RmGST at an atomic level. Like other m-class GSTs, the flexible m loop (m1) of RmGST was observed. M1 seems to shield the active sites from the bulk. A RmGST dimer is stabilized by the lock-and-key motif (F57 as "key") and hydrogen bonds of R82-E91 and R82-D98 at the dimer interface. Without substrates, conserved catalytic Y116 and N209 can interact with V112, G210 (for Y116) and F215 (for N209). Overall, most residues involving in RmGST function and stability are similar to other m-class GSTs. This implies similar structural stability and catalytic activity of RmGST to other GSTs. An insight obtained here will be useful for management of acaricide resistance and tick control.Communicated by Ramaswamy H. Sarma.

Elucidating structure and dynamics of glutathione S-transferase from Rhipicephalus (Boophilus) microplus.

Unfolding of a coarse grained COVN protein from its native configuration shows a linear response with increasing temperature followed by a nonmonotonic double peaks in its radius of gyration. The protein conforms to a random coil of folded segments in native state with increasing tenuous and globular structures in specific temperature regimes where the effective dimensions of corresponding structures D is about 1.6 to 2.4. Thermal agitation alone is not sufficient to fully eradicate its segmental folding as few folds are found to persist around such residues as 65W, 110Y, 224L, 374P even at high temperatures.

Warin Rangubpit

Papers

Furofuran lignans as a new series of antidiabetic agents exerting α-glucosidase inhibition and radical scarvenging: Semisynthesis, kinetic study and molecular modeling.

Thermally induced structural organization of nanodiscs by coarse-grained molecular dynamics simulations.

Globular bundles and entangled network of proteins (CorA) by a coarse-grained Monte Carlo simulation

Elucidating structure and dynamics of glutathione S-transferase from Rhipicephalus (Boophilus) microplus.

Thermal induced unfolding refolding of a nucleocapsid COVN protein