GC-MS analysis and cytotoxic activity of the n-hexane fraction from Curcuma sahuynhensis Škornick. & N.S.Lý leaves collected in Vietnam

Curcuma sahuynhensis Škornick. & N.S.Lý is an endemic plant in Vietnam that has been used by the Sa Huynh people as a spice and medicine to cure illnesses linked to digestive disorders. Very little information is available so far about the chemical composition and biological effects of C. sahuynhensis. To find new pharmaceutical ingredients, the in vitro cytotoxic effect and the chemical profile of C. sahuynhensis leaf extract were investigated. In this study, the percolation method and liquid-liquid dispersion technique were used to extract dry sample powder. The chemical composition was detected by gas chromatography-mass spectrometry (GC-MS). The Sulforhodamine B and MTT methods were used to determine the cytotoxic activity. The chemical composition analysis showed that the leaf extract contained 14 components. The major components in the n-hexane extract were 6,10,14-trimethylpentadecan-2-one, phytol, 1-ethylbutyl hydroperoxide, isoborneol, 1-methylpentyl hydroperoxide, and neophytadiene. On human cancer cell lines, namely MFC-7, SK-LU-1, Hela, MKN-7, and HL-60, the leaf extract showed dose-dependent cytotoxic activity, with IC50 values ranging from 221.70±10.24 to 369.42±10.60 ?g/mL. The present study provides significant information on the chemical components and cytotoxic effects of the n-hexane extract from C. sahuynhensis leaves. The findings will continue to be crucial in future research on the evaluation of secondary metabolite compound analysis for cancer therapeutic effects

Students’ Perceptions on Blended Synchronous Learning in the Postcrisis Era

With the severe impacts of the Covid-19 pandemic, the educational systems have to be reformed and evolved. Blended synchronous learning has become an attractive tendency in education worldwide as the technology has mushroomed recently and attracts a vast number of users and researchers. Therefore, the current study was conducted to investigate students’ overall perceptions of blended synchronous learning as well as its benefits and challenges. 163 participants in the study have experienced ENT courses in a blended synchronous learning environment for 105 hours within 7 weeks. The instrument employed in the quantitative phase was 27 items adapted from studies by Rahman et al. (2015), López-Pérez et al. (2011), and Wu et al. (2010). Additionally, semi-structured interviews were used to have a deeper understanding of the research issues. Results indicate that more than half of participants had good perceptions about the blended synchronous learning environment and perceived various benefits as well as challenges of it. Moreover, these findings are supplemented with illustrative quotes from interview transcripts to compare and contrast with previous findings reported in the literature, and therefore this study contributes to the field by offering the learners\u27 voices

Effect of Camellia flava (Pitard) Sealy flower extract on the degeneration of Islets of Langerhans and insulin resistance in alloxan-induced hyperglycemia model on Swiss albino mice

Diabetes has always been a matter of concern to health experts as well as the community due to the increasing number of patients with diabetes and the severe consequences it may cause. Many attempts have been made to discover new treatment options for diabetes, and herbal medicines are currently considered to have great potential. This study was conducted to evaluate the effect of Camellia flava flower extract on the degeneration of the islets of Langerhans and insulin resistance in an alloxan-induced hyperglycemia model in Swiss albino mice. Hyperglycemic conditions were induced by alloxan (55 mg/kg, i.v.). The animals were then treated with glibenclamide (10 mg/kg, p.o.) and flower extract at doses of 1.09 and 2.19 g/kg, p.o. The results showed that the blood glucose, AUC, HbA1c, and HOMA-IR levels of two groups of mice receiving flower extract were considerably lower than those of the hyperglycemic untreated group (p < 0.05). The body weights of these two groups were also lower than the untreated group on the last day of the experiment, though the differences were not significant (p > 0.05). However, this was not observed when assessing insulin levels as well as relative organ weights. In biochemical tests, creatinine and AST and ALT concentrations were evaluated. There was no significant variation in creatinine and AST concentrations between the five experimental groups, whereas mice treated with glibenclamide and flower extract at both doses showed a remarkable decline in ALT concentration (p < 0.05). The hepatic histomicrographs were consistent with ALT results, while the H&E staining of kidneys showed no difference between groups. Histomicrographs of the pancreas revealed that the treatment groups using glibenclamide and flower extract had larger islets of Langerhans than those of the alloxan-treated group. Based on these results, this study demonstrated that Camellia flava flower extract exerted several beneficial effects, including blood sugar level reduction, weight loss promotion, and organ protection, hence making it a new potential herbal medication for the management of diabetes

Aerospace competition, investor attention, and stock return comovement

Fierce aerospace competition among global superpowers has resulted in strong public attention on satellite launch events in the U.S. Given limited attentional resources, U.S. investors pay more attention to market-level shocks than to firm-specific shocks, making stock returns comove more with the market on satellite launch days than on other days. We find that the effect is significantly stronger for military-related satellite launches, launches before the dissolution of the former Soviet Union, and international satellite launches by other competitors, highlighting a greater concern for national security. A trading strategy that exploits the potential satellite-induced mispricing yields an annualized abnormal risk-adjusted return of up to 17% within the three-day window around launch date. Our results are robust to a battery of robustness analyses that consider the different characteristics of satellite launches, the exclusion of aerospace firms, and stock return comovement with industries.</p

The protective effects of young pomelo fruits extract against acute hyperlipidemia and high-fat diet-induced obese mice

Introduction: Pomelo (柚 in Mandarin) (Citrus grandis L. Osbeck), a long-used fruit in Asia and China, is commonly used in traditional Chinese medicine. Pomelo is also a culturally significant fruit tree in Vietnam, renowned for its culinary and medicinal value. Young pomelo fruits possess high levels of flavonoids, but their research significance remains limited. Due to its relatively unknown potential, young pomelo is usually discarded during gardening maintenance leading to waste. This study aims to determine the naringin content and investigate the ameliorative effect on lipid profile of young pomelo extracts. Methods: Two mouse models of hyperlipidemia, specifically tyloxapol and a high-fat diet (HFD) model, were utilized to assess the effects of young pomelo extracts. Tyloxapol decreases the clearance of lipoprotein and leads to acute endogenous hyperlipidemia, while a high fat diet causes obesity among mice. The hypolipidemic effect of young pomelo extract was assessed through the level of serum triglyceride (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-c), and high-density lipoprotein-cholesterol (HDL-c), while its ameliorative effect was assessed through physical changes of mice and histological changes of their livers. Results: In the tyloxapol model, the naringin-rich young pomelo extracts exhibited promising effects in the treatment of hyperlipidemia. Notably, they significantly reduced total cholesterol, triglycerides, and LDL-c levels while elevating HDL-c levels. In the HFD model, the young pomelo extracts demonstrated similar effects on the biochemical lipid profiles. Moreover, the young pomelo extracts possess a protective effect against HFD-induced hepatosteatosis and hepatic necroinflammation. These findings align with existing literature, highlighting the potential utilization of young pomelo fruits. Discussion: The findings have significant implications for the development of novel therapeutic approaches targeting obesity and related metabolic disorders. Furthermore, the study contributes to promoting sustainable agriculture practices by emphasizing the utilization of young pomelo fruits that would otherwise go to waste. Overall, this study provides valuable insights into establishing a high-fat diet-induced obesity model, tyloxapol-induced hyperlipidemia and demonstrates the potential of young pomelo as a rich source of naringin

When Hollywood movies steal the show, stock returns dance more with the market!

Hollywood film releases attract U.S. investors' attention away from the financial markets. This is reflected in lower trading activity and abnormal Google search volume for firm names between film and non-film days. The resultant investor inattention leads to a significantly higher stock return comovement with the market on film release days. Interestingly, films with A-list star actors and blockbuster movies exhibit a more pronounced impact than their counterparts. Finally, we show that being aware of this Hollywood film-induced mispricing can yield an annualized abnormal risk-adjusted return of up to 13.5% within five days around the release events.</p

Purification Process of Mangiferin from Mangifera indica L. Leaves and Evaluation of Its Bioactivities

Mangiferin (C19H18O11) is a C-glucoside xanthone that is mainly found in the leaves of mango (Mangifera indica L). The compound has been recognized for several pharmacological values, including antioxidant and antibacterial activities. Therefore, the present study aims to utilize the old leaves of mango as a potential source for mangiferin extraction and purification, and evaluate its antimicrobial and antioxidant properties. In the present study, mangiferin was extracted from a local variety of mango leaves using ultrasonic-assisted extraction methods and ethanol as the extraction solvent. The crude ethanolic extract of mangiferin was then purified by the liquid–liquid fractionation method with dichloromethane and ethyl acetate, then further separated by HPLC. The crude extract, ethyl acetate fractions and purified mangiferin were investigated for anti-microorganism activity against Escherichia coli, Salmonella spp. and Aspergillus flavus by using the paper disc diffusion assay. The results have shown that the extraction efficiency was 14.17%. The obtained mangiferin was 1.97 g of content and 94.2% of purity. The oxidation resistance of purified mangiferin was 1.77 times higher than the crude extract and 1.05 times higher than the standard mangiferin (IC50 = 13.841 μg/mL). However, the purified mangiferin has shown no inhibitory action against the experimental strains of microorganisms. The findings from the present study suggest an effective scheme of extraction and purification to obtain mangiferin from the local variety of mango with high purity and antioxidant potential

Phenolic Profiles, Antioxidant, Antibacterial Activities and Nutritional Value of Vietnamese Honey from Different Botanical and Geographical Sources

Honey is a natural product made by honeybees, its composition depends on factors such as climate, soil and plant source. In this study, the nutritional parameters, phenolic composition, antioxidant activity and antibacterial ability of 30 different types of honey of different botanical and geographical origins in Vietnam were investigated. The study focused on the characterization and evaluation of the influence of plant origin and geographical location on physical–chemical properties and biological activities (antioxidant and antibacterial). The obtained results show that all honey samples meet quality standards according to international standards and Vietnamese standards, except for some exceptions recorded in moisture, 5-hydroxymethylfurfural (HMF) value and ash. These samples were explored for the detection of 13 polyphenols by using high-performance liquid chromatography (HPLC). The classification of honey samples collected from different regions and botanical sources was performed by principal component analysis (PCA), and it was observed that certain phenolic compounds contributed to the identification of honey samples. In addition, the correlation between physicochemical properties, chemical composition and biological activity of most honeys was also first clarified in this study. Overall, our data provide an overview data set and essential results in creating a database on the world honey trait map

Spontaneous thrombosis of a large unruptured intracranial aneurysm causing ischemic stroke due to occlusion of the parent artery: A case report and literature review

Spontaneous thrombosis of an unruptured large or giant saccular intracranial aneurysm is a well-known phenomenon and can cause ischemic stroke (IS), which is a rare event. The possible pathogenic mechanisms of IS include distal embolic occlusion secondary to migration of the intra-aneurysmal thrombus, occlusion of the parent artery lumen caused by the retrograde extension of the aneurysmal thrombosis, external compression of the parent artery due to the increased aneurysmal mass effect. Among these, IS due to simultaneous thromboses of the aneurysm and its parent artery is extremely rare, with only a few cases reported in the literature. Herein, we present a case of a 18-year-old woman who suffered an acute IS, attribute to spontaneous complete thrombosis of an unruptured large saccular aneurysm of the right middle cerebral artery with occlusion of the parent artery, and we review the literature simultaneously

Determination of Caffeine, Chlorogenic Acid, Total Phenolic Contents, and Antioxidant Capacities for Arabica and Robusta Coffee from Vietnam

In Vietnam, the cultivation and production of coffee have been expanding over the past few decades and are known as an important part of the national economy. However, the scientific data regarding the internal compositions of coffee have still been limited, especially the changes during the processing, typically the roasting period. The present study aimed to demonstrate an insight into the variations in chlorogenic acid, caffeine, total phenolic contents (TPCs), and trolox equivalent antioxidant capacities for two common coffee species, that is, Robusta and Arabica, and three roasting levels, that is, light, medium, and dark. Generally, Robusta coffee performed higher chlorogenic acid, caffeine, and TPCs, resulting in dominant antioxidant capacities compared to Arabica. High Pearson correlation coefficients (calculated by SPSS) were found for most pairs of parameters, r > 0.80. Regarding roasting levels, a descending order was highlighted for most analytical parameters: light > medium > dark. Two parallel processes in the roasting period were revealed by observing the antioxidant capacities, that is, thermal degradation and formation of other antioxidants by the Maillard reaction. Principal component analysis (SIMCA-P 11) was attempted to discriminate the available coffee samples by their species and roasting levels, indicating proper classification (the cumulative variance is 95.3%).</p