Total syntheses of schizandriside,saracoside and (±)-isolariciresinol with antioxidant activities

Lignans are widely distributed in plants and exhibit significant pharmacological effects, including anti-tumor and antioxidative activities. Here, we describe the total synthesis of schizandriside (1), a compound we previously isolated from Saraca asoca by monitoring antioxidative activity using the 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay. Starting from a tandem Michael-aldol reaction, the lignan skeleton was synthesized in 6 steps, including a cyclization step. To determine the stereochemistry of 1, we synthesized the natural product (±)-isolariciresinol (18) from alcohol 17. Comparison of the spectral data showed good agreement. Glycosylation was investigated using four different glycosyl donors. Only the Koenigs–Knorr condition using silver trifluoromethanesulfonate with 1,1,3,3-tetramethylurea provided the glycosylated product. Deprotection and purification using reverse-phase high-performance liquid chromatography gave schizandriside (1) and its diastereomer saracoside (2). Synthesized 1, 2 and 18 showed antioxidant activity with IC₅₀?=?34.4, 28.8, 53.0 μM, respectively.     

The anti-tumor effect of pachymic acid on osteosarcoma cells by inducing PTEN and Caspase 3/7-dependent apoptosis

Pachymic acid (PA) is a lanostane type triterpenoid isolated from Poria cocos, which possesses an anti-tumor effect in breast cancer, prostate cancer, lung cancer, and bladder cancer cells. In this study, we investigated the effect of PA on the growth and apoptosis of human immortalized cell line (HOS) and primary osteosarcoma cells by a Cell Counting Kit-8 (CCK-8) and Annexin V and propidium iodide (PI) staining, respectively. Western blot was used to measure the expression of cleaved Caspase 3, PTEN, and AKT, as well as the AKT phosphorylation. The Caspase 3 activity was determined using the Caspase-3 Colorimetric Assay Kit. From the results, PA significantly reduced cell proliferation in a concentration- and time-dependent manner. PA also induced cell apoptosis in a dose-dependent fashion. PA treatment led to increased Caspase 3 activation and PTEN expression, as well as reduced AKT phosphorylation. Moreover, Ac-DEVD-CHO (a Caspase 3/7 inhibitor) pre-treatment or PTEN knockdown partially blocked the effects of PA on cell proliferation and apoptosis. Caspase 3/7 inhibitor had an additive effect with PTEN knockdown. Collectively, our results suggested that induction of apoptosis by PA was mediated in part by PTEN/AKT signaling and Caspase 3/7 activity. This study provides evidence that PA might be useful in the treatment of human osteosarcoma.     

Two new secoiridoid glucosides and a new lignan from the roots of <Emphasis Type="Italic">Ilex pubescens</Emphasis>

Two new secoiridoid glucosides, ilexpublignoside (1), pubzenoside (2), and a new lignan, ilexlignan B (3), along with seven known compounds (4–10) were isolated from the roots of Ilex pubescens for the first time. Their chemical structures were elucidated on the basis of extensive spectroscopic methods, including IR, UV, HR-ESI–MS, CD, NMR experiments, as well as comparison with the reported data.     

Singular value based characterization and analysis of thermal patches for early breast abnormality detection

The purpose of this study is to develop a novel breast abnormality detection system by utilizing the potential of infrared breast thermography (IBT) in early breast abnormality detection. Since the temperature distributions are different in normal and abnormal thermograms and hot thermal patches are visible in abnormal thermograms, the abnormal thermograms possess more complex information than the normal thermograms. Here, the proposed method exploits the presence of hot thermal patches and vascular changes by using the power law transformation for pre-processing and singular value decomposition to characterize the thermal patches. The extracted singular values are found to be statistically significant (p?<?0.001) in breast abnormality detection. The discriminability of the singular values is evaluated by using seven different classifiers incorporating tenfold cross-validations, where the thermograms of the Department of Biotechnology-Tripura University-Jadavpur University (DBT-TU-JU) and Database of Mastology Research (DMR) databases are used. In DMR database, the highest classification accuracy of 98.00% with the area under the ROC curve (AUC) of 0.9862 is achieved with the support vector machine using polynomial kernel. The same for the DBT-TU-JU database is 92.50% with AUC of 0.9680 using the same classifier. The comparison of the proposed method with the other reported methods concludes that the proposed method outperforms the other existing methods as well as other traditional feature sets used in IBT based breast abnormality detection. Moreover, by using Rank1 and Rank2 singular values, a breast abnormality grading (BAG) index has also been developed for grading the thermograms based on their degree of abnormality.     

Estimating transmitted power density from mobile phone: an epidemiological pilot study with a software modified phone

The aims of this study were to evaluate the weekly and annual cumulative radiofrequency-electromagnetic field (RF-EMF) exposure attributed to mobile phone (MP) use, and assess whether a novel app (Quanta Monitor?) could be employed in a small human sample to characterise the RF-EMF exposures associated with the use of MPs. Ten participants provided their two months’ daily objective data on their MP exposures (i.e. transmitted and received power densities) attributed to different modes of MP usage such as cellular calls, cellular data and Wi-Fi. The results demonstrated that total transmitted power density (cellular phone calls, data and Wi-Fi surfing) could be many orders of magnitude higher than that from the total received power density. Of the total transmitted power density, cellular data use contributed the largest portion. Our study showed that Quanta Monitor? could be employed in prospective assessment of exposures to MPs in epidemiological studies.