First total synthesis of a naturally occurring nucleoside disulfide:9-(5'-Deoxy-5'-thio-β-D-xylofuranosyl)adenine disulfide

A naturally occurring nucleoside disulfide, 9-（51-deoxy-5t-thio-β-D-xylofuranosyl）adenine disulfide, was first synthesized from o-xylose over 7 steps in 20% overall yield. The key step involved Vorbri.iggen glycosylation of silylated N6-benzoyladenine with xylose diacetate moiety.

Altitude-dependent distribution of 137Cs in the environment:a case study of Aragats massif, Armenia

This paper considers the distribution of technogenic 137Cs and naturally occurring radionuclides:238 U,232 Th and40 R concentrations in soils and 137Cs in atmospheric dry depositions by altitudinal belts of the Aragats mountain massif,Republic of Armenia.Undisturbed soil samples were collected at altitudes from 1000 to 3200 m.For the determination of geochemical variability,two soil sampling campaigns were undertaken.Atmospheric dry depositions were sampled from five stations at1100-3200 m collected onto organic fiber filters between June and December 2016.137Cs activity was measured using a high-purity Germanium detector coupled to a multichannel analyzer(Canberra).Results indicated that specific activity of 137Cs in soils at 1000 m is495-528 Bq m^-2,andat3200 mis10,500-11,470 Bq m^-2.No correlation observed for 137Cs versus naturally occurring radionuclides,which varies in distribution by altitude.Specific activities of 137Cs in dry atmospheric depositions varies from 1.06 at 846 m to2.37 Bq m^-2 per quarter at 3200 m and increases as the altitude increases.Activities of 137Cs in soil and dry atmospheric deposition correlated significantly,and 137Cs activity in soils and atmospheric dry depositions decrease as the absolute altitude decreases.The 50-year effective dose from exposure to 137Cs fallout varies with altitude from 0.007 to 1.42 m Sv.

Synthesis,Mass Spectrometric Studies,and Biological Evaluation of 3,5-Dimethoxyhomophthalic Acid and Related Compounds

3,5-Dimethoxyhomophthalic acid was synthesized in four steps from 3,5-dimethoxycinnamic acid via a series of reactions including cyclization of 3-（3＇,5＇-dimethoxyphenyl）propionic acid to 5,7-dimethoxy-1-indanone and oxidative decomposition of methyl-2-hydroxy-2-[5,7-dimethyoxy-1-oxo-1H-inden-2（3H）-ylidene]acetate to 3,5-dimethoxyhomophthalic acid.The synthesized compounds were characterized by elemental analysis,IR,1H NMR,and MS.The biological evaluation experiments of 3,5-dimthoxyhomophthalic acid and the related synthesized compounds were also carried out.Naturally occurring biologically active isocoumarins were prepared in a single step by the condensation of the homophthalic acid with appropriate acid chlorides.

Antioxidant Effect of Bovine Plasma Proteins Modified via Maillard Reaction on n3 Fortified Beef Patties

This work aimed to develop a healthier meat product, by improving nutritional properties related to lipid profile, using a Maillard reaction product (MRP) obtained from recycling blood from local slaughterhouses as antioxidant. Soybean oil was used as partial fat replacer and the lipid profile was modified as a decrease in the n6/n3 ratio (11.59 to 9.50), and atherogenic and trombogenic index (from 0.42 to 0.27 and 0.94 to 0.56 respectively) was observed. Beef patties were added with two MRP levels (1% w/w and 3% w/w). Patties with no antioxidants were used as control and patties containing 0.01% w/w of butylhydroxyanisole (BHA) were used as reference. Oxidative stability of refrigerated vacuum-packed patties was evaluated during 15 days of storage. Results showed 3% of MRP as the most appropriate concentration to prevent lipid oxidation with inhibition percentages of 75%, and 9 days as the limit time of chilled storage regarding consumers’ perceptions.

Plant-derived nanovesicles as an emerging platform for cancer therapy

Plant-derived nanovesicles(PDNVs)derived from natural green products have emerged as an attractive nanoplatform in biomedical application.They are usually characterized by unique structural and biological functions,such as the bioactive lipids/proteins/nucleic acids as therapeutics and targeting groups,immune-modulation,and long-term circulation.With the rapid development of nanotechnology,materials,and synthetic chemistry,PDNVs can be engineered with multiple functions for efficient drug delivery and specific killing of diseased cells,which represent an innovative biomaterial with high biocompatibility for fighting against cancer.In this review,we provide an overview of the state-of-theart studies concerning the development of PDNVs for cancer therapy.The original sources,methods for obtaining PDNVs,composition and structure are introduced systematically.With an emphasis on the featured application,the inherent anticancer properties of PDNVs as well as the strategies in constructing multifunctional PDNVs-based nanomaterials will be discussed in detail.Finally,some scientific issues and technical challenges of PDNVs as promising options in improving anticancer therapy will be discussed,which are expected to promote the further development of PDNVs in clinical translation.

High Amounts of Halogenated Natural Products in Sperm Whales(Physeter macrocephalus)from Two Italian Regions in the Mediterranean Sea

Halogenated natural products(HNPs)are considered to be emerging contaminants whose environmental distribution and fate are only incompletely known.Therefore,several persistent and bioaccumulative HNP groups,together with manmade polychlorinated biphenyls(PCBs)and polybrominated diphenyl ethers(PBDEs),were quantified in the blubber of nine sperm whales(Physeter macrocephalus)stranded on the coast of the Mediterranean Sea in Italy.The naturally occurring polybrominated hexahydroxanthene derivatives(PBHDs;sum of TetraBHD and TriBHD)were the most prominent substance class with up to 77,000 ng/g blubber.The mean PBHD content(35,800 ng/g blubber)even exceeded the one of PCBs(28,400 ng/g blubber),although the region is known to be highly contaminated with manmade contaminants.Based on mean values,Q1∼PBDEs>MeO-BDEs∼2,2′-diMeO-BB 80 and several other HNPs followed with decreasing amounts.All blubber samples contained an abundant compound whose molecular formula(C_(16)H_(19)Br_(3)O_(2))was verified using high-resolution mass spectrometry.The only plausible matching isomer was(2S,4′S,9R,9′S)-2,7-dibromo-4′-bromomethyl-1,1-dimethyl-2,3,4,4′,9,9′-9,9′-hexahydro-1H-xanthen-9-ol(OH-TriBHD),a hydroxylated secondary metabolite previously detected together with TriBHD and TetraBHD in a sponge known to be a natural producer of PBHDs.The estimated mean amount of the presumed OH-TriBHD was 3000 ng/g blubber,which is unexpectedly high for hydroxylated compounds in the lipids of marine mammals.

Berberine improves central memory formation of CD8^(+)T cells:Implications for design of natural product-based vaccines

Berberine(BBR)as one of the most effective natural products has been increasingly used to treat various chronic diseases due to its immunosuppressive/tolerogenic activities.However,it is unknown if BBR can be applied without abrogating the efforts of vaccination.Here we show that priming of CD8^(+)T cells in the presence of BBR lead to improved central memory formation(Tcm)with substantially reduced effector proliferation,primarily orchestrated through activation of AMPK and Stat5.Tcm derived from vaccinated mice fed with BBR were able to adoptively transfer protective immunity to naIve recipients.Vaccination of BBR-fed mice conferred better memory protection against infection without losing immediate effector efficacy,suggesting appreciable benefits from using BBR in vaccination.Thus,our study may help to lay the groundwork for mechanistic understanding of the immunomodulatory effects of natural products and their potential use as adjuvant that allows the design of novel vaccines with more desirable properties.

A total synthesis of mycalisine A

In this paper,we report a total synthesis of a naturally occurring pyrrolo[2,3-d]pyrimidine nucleoside, mycalisine A.Our synthetic strategy uses D-xylose as the starting material and Vorbr（u｜¨）ggen glycosylation as the key step.Mycalisine A was synthesized in 11 steps with a 15%overall yield.

The Relationship between Pendant Phosphate Groups and Mechanical Properties of Polyisoprene Rubber

It is still a great challenge to mimic the structure and function of natural rubber by introducing polar components into synthetic polyisoprene.In order to explore the function of phosphate groups on the mechanical properties of polyisoprene rubber,a terminally functionalized compound(PIP-P)containing phosphate groups was synthesized and further vulcanized to prepare the model compound V-PIP-P.Through analyzing the test results,it was found that these phosphate groups formed polar aggregates in non-polar polyisoprene rubber matrix,serving as an additional dynamic cross-linking sites,which increases the cross-linking density and improves mechanical properties.The influence of the phosphate groups on the strain-induced crystallization(SIC)was further investigated via synchrotron wide-angle X-ray diffraction(WAXD)experiment.These phosphate group aggregates not only reduced the onset strain of SIC,but also slowed down the molecular chain mobility,which hinder the crystal lateral growth.The above results help us to gain a deeper understanding for the function of phosphate groups in the formation of"naturally occurring network"and guide the molecular design of next generation polyisoprene rubber.

Macleayine,a new alkaloid from Madeaya cordata

Macleayine （1）, a new natural occurring alkaloid with a unique spiro [furanone-piperidinedione] framework, was isolated from the aerial parts ofMacleaya cordata. Its unusual structure was established by extensive spectroscopic analyses, computer-assisted structure elucidation software （ACD/Structure Elucidator）, quantum chemistry calculations and ECD calculation. The result of virtual molecular docking predicted the compound can enhance the effects of insulin, and may be used to treat tvpe II diabetes.