Saponins of North Atlantic Sea Cucumber: Chemistry, Health Benefits, and Future Prospectives.

Frondosides are the major saponins (triterpene glycosides) of the North Atlantic sea cucumber (Cucumaria frondosa). Frondosides possess amphiphilic characteristics due to the presence of various hydrophilic sugar moieties and hydrophobic genin (sapogenin). Saponins are abundant in holothurians, including in sea cucumbers that are widely distributed across the northern part of the Atlantic Ocean. Over 300 triterpene glycosides have been isolated, identified, and categorized from many species of sea cucumbers. Furthermore, specific saponins from sea cucumbers are broadly classified on the basis of the fron-dosides that have been widely studied. Recent studies have shown that frondoside-containing extracts from C. frondosa exhibit anticancer, anti-obesity, anti-hyperuricemic, anticoagulant, antioxidant, antimicrobial, antiangiogenic, antithrombotic, anti-inflammatory, antitumor, and immunomodulatory activities. However, the exact mechanism(s) of action of biological activities of frondosides is not clearly understood. The function of some frondosides as chemical defense molecules need to be understood. Therefore, this review discusses the different frondosides of C. frondosa and their potential therapeutic activities in relation to the postulated mechanism(s) of action. In addition, recent advances in emerging extraction techniques of frondosides and other saponins and future perspectives are discussed.

Exercise, CaMKII, and type 2 diabetes.

Individuals who exercise regularly are protected from type 2 diabetes and other metabolic syndromes, in part by enhanced gene transcription and induction of many signaling pathways crucial in correcting impaired metabolic pathways associated with a sedentary lifestyle. Exercise activates Calmodulin-dependent protein kinase (CaMK)II, resulting in increased mitochondrial oxidative capacity and glucose transport. CaMKII regulates many health beneficial cellular functions in individuals who exercise compared with those who do not exercise. The role of exercise in the regulation of carbohydrate, lipid metabolism, and insulin signaling pathways are explained at the onset. Followed by the role of exercise in the regulation of glucose transporter (GLUT)4 expression and mitochondrial biogenesis are explained. Next, the main functions of Calmodulin-dependent protein kinase and the mechanism to activate it are illustrated, finally, an overview of the role of CaMKII in regulating GLUT4 expression, mitochondrial biogenesis, and histone modification are discussed.

Role of CaMKII in the regulation of fatty acids and lipid metabolism.

BACKGROUND & AIMS: Previous studies have reported the beneficial roles of the activation of calmodulin-dependent protein kinase (CaMK)II to many cellular functions associated with human health. This review aims at discussing its activation by exercise as well as its roles in the regulation of unsaturated, saturated, omega 3 fatty acids, and lipid metabolism. METHODS: A wide literature search was conducted using online database such as 'PubMed', 'Google Scholar', 'Researcher', 'Scopus' and the website of World Health Organization (WHO) as well as Control Disease and Prevention (CDC). The criteria for the search were mainly lipid and fatty acid metabolism, diabetes, and metabolic syndrome (MetS). A total of ninety-seven articles were included in the review. RESULTS: Calmodulin-dependent protein kinase activation by exercise is helpful in controlling membrane lipids related with type 2 diabetes and obesity. CaMKII regulates many health beneficial cellular functions in individuals who exercise compared with those who do not exercise. Regulation of lipid metabolism and fatty acids are crucial in the improvement of metabolic syndrome. CONCLUSIONS: Approaches that involve CaMKII could be a new avenue for designing novel and effective therapeutic modalities in the treatment or better management of metabolic diseases such as type 2 diabetes and obesity.

Exploration of Modern Chromatographic Methods Coupled to Mass Spectrometric Techniques for Trace Element and Chemical Composition Analyses in the Leaf Extracts of Kigelia africana.

The use of Kigelia africana (Lam.) Benth. plant dates back to last century. The different parts of the plant exhibited various pharmacological activities. But literature search revealed scanty use of the leaf extract owing to few information regarding the various phytochemical constituents. The aim of this study is, therefore, to profile the chemical compounds through the use of omics-based approach. Ultrahigh-pressure liquid chromatography quadrupole-time-of-flight tandem mass spectrometry (qTOF-UPLC/MS) alongside gas chromatography quadrupole time-of-flight tandem mass spectrometry (qTOF-GC/MS) were used to profile these chemical compounds. Inductively coupled plasma optical emission spectrometry (ICP-OES) was used to determine the concentration of trace elements as well as limit of detection (LOD) and quantification (LOQ). For broader metabolite determination, a modified sample preparation was employed and to ascertain the cytoprotective potential of the leaf extract, MTT assay on A375 human melanoma cell lines was carried out. Sixty-eight peaks were characterized with the identification of 275 metabolites where 8 of these were confirmed. Of importance is the identification of eugenol; a polyphenolic compound at m/z 165.09 on fragments 119.09, 147.08, 109.10, 137.10, and 137.06. for qTOF-GC/MS analysis, 232 metabolites were identified consisting of terpenes, fatty acids, furans, amines, amides, and alkanes. The concentration of trace elements in the leaf extract ranged from 0.08 for Zn to 0.28 mg/kg for Fe with low concentrations of Cd according to the recommendation of European Legislation. The leaf showed higher inhibition of growth against A375 human melanoma cell lines in a dose-dependent manner. The results showed that K. africana leaf contained various pharmaceuticals, nutraceuticals, designer drugs, and phytochemicals, and these chemicals have minimal cytotoxic side effects. To the best of our knowledge, this is the first study providing information on the various secondary metabolites in the leaf extract through the use of omics-based approach. Therefore, the leaves of K. africana plant can be used as antiinflammatory, antimicrobial, antibacterial, antifungal, and antiproliferative agents for industrial, therapeutic, and medicinal applications. Graphical Abstract.

Vascular function and cardiovascular risk in a HIV infected and HIV free cohort of African ancestry: baseline profile, rationale and methods of the longitudinal EndoAfrica-NWU study.

BACKGROUND: People living with the Human Immunodeficiency Virus (PLHIV) have an increased susceptibility to develop non-communicable diseases such as cardiovascular disease (CVD). Infection with HIV contributes to the development of CVD independent of traditional risk factors, with endothelial dysfunction being the central physiological mechanism. While HIV-related mortality is declining due to antiretroviral treatment (ART), the number of deaths due to CVD is rising in South Africa - the country with the highest number of PLHIV and the world's largest ART programme. The EndoAfrica study was developed to determine whether HIV infection and ART are associated with cardiovascular risk markers and changes in vascular structure and function over 18 months in adults from different provinces of South Africa. This paper describes the rationale, methodology and baseline cohort profile of the EndoAfrica study conducted in the North West Province, South Africa. METHODS: In this case-control study, conducted between August 2017 and June 2018, 382 volunteers of African descent (276 women; 106 men), comprising of 278 HIV infected and 104 HIV free individuals were included. We measured health behaviours, a detailed cardiovascular profile, and performed biomarker analyses. We compared baseline characteristics, blood pressure, vascular function and biochemical markers between those infected and HIV free. RESULTS: At baseline, the HIV infected participants were older (43 vs 39 years), less were employed (21% vs 40%), less had a tertiary education (7% vs 16%) and their body mass index was lower (26 vs 29 kg/m2) than that of the HIV free participants. While the cardiovascular profile, flow-mediated dilation and pulse wave velocity did not differ, glycated haemoglobin was lower (p = 0.017) and total cholesterol, high density lipoprotein cholesterol, triglycerides, gamma-glutamyltransferase and tobacco use were higher (all p < 0.047) in PLHIV. CONCLUSION: Despite PLHIV being older, preliminary cross-sectional analysis suggests that PLHIV being treated with ART do not have poorer endothelial or vascular function compared to the HIV free participants. More detailed analyses on the baseline and follow-up data will provide further clarity regarding the cardiovascular profile of South Africans living with HIV.

Evaluation of Phytochemicals, Antioxidants, Trace Elements in Kigelia africana Fruit Extracts and Chemical Profiling Analysis Using UHPLC-qTOF-MS2 Spectrometry.

The study aimed at evaluating the phytochemical composition, antioxidant potentials and the levels of trace elements in the fruit extract of Kigelia africana obtained by different extraction solvents in order to ascertain its numerous pharmacological activities and identify the different chemical compounds responsible for these activities. The crude extract in ethanol and four other solvent fractions (hexane, ethylacetate, butanol and aqueous) were obtained for phytochemical screening. Antioxidant potentials of K. africana fruit were investigated spectrophotometrically using hydroxyl ion scavenging (OH-) activity, metal ion chelating activity, anti-lipid peroxidation activity as well as total antioxidant capacity assays. Trace element (Mn, Zn, Cd, Ni, Cu, Pb, Cr, Co and Fe) levels were measured using a plasma-emission spectrometer that has an auto sampler AS 93-plus and coupled with Nebulizer CETAC U-6000AT+ after microwave acid digestion of the fruit extracts. Chemical identification was performed using ultra-high-pressure liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-qTOF-MS2). Kigelia africana fruit extracts obtained showed a variety of bioactive phytochemical compounds including phenolic acids, flavonoids, saponins, tannins and glycosides. The total antioxidant capacity activities of the aqueous, butanol, ethanol, hexane and ethylacetate extracts are 15.04, 52.11, 44.95, 79.27 and 175.20 mg AAE/g. Metal ion chelating activity showed significant correlation with lipid peroxidation inhibition activity at p ≤ 0.01 and with OH- scavenging activity at p ≤ 0.05. PCA analysis revealed that all the extract/fractions have higher total antioxidant activities compared to aqueous extract with hexane extract exhibiting the highest radical scavenging potential. HCA showed similarities with three well-defined clusters and PLS regression was used to predict total antioxidant activity. High sensitivity by low values of limits of detection and quantification was observed ranging from 0.021 to 0.085 mg/ml and 0.063 to 0.258 mg/ml for Zn and Fe respectively. Ethylacetate extract had high concentration of Fe (0.5656 mg/kg). For the standardization of the K. africana fruit extract, 244 chemical compounds were identified by measuring m/z values with threshold override of 100,000 and analysing mass spectrometer fragmentation behaviour while 16 of these were confirmed. Kigelia africana fruit extract is a good source of antioxidant and possess maximum accepted concentration of trace elements according to European legislation (1881/2006/EC). The metabolites identified exhibited numerous pharmacological activities. The method and results suggest the applicability for commercial use of this K. africana fruit in the treatment of oxidative-related diseases. Graphical abstract The phytochemical, antioxidant and trace element composition of crude ethanol extract, hexane, butanol, aqueous and ethylacetate extracts of Kigelia africana fruit were determined. The fruit extracts were found to possess good antioxidant activity, maximum acceptable amount of essential trace elements as well as the presence of bioactive phytochemicals. K. africana fruit would be an ideal candidate in improving human health and thus the management of oxidative-related diseases such as diabetes, by involving in the antioxidant defense system against free radical generation.

Evaluation of free radical scavenging capacity of methoxy containing-hybrids of thiosemicarbazone-triazole and their influence on glucose transport.

BACKGROUND: Diabetes mellitus is a metabolic disease in which the body is unable to produce insulin or respond to insulin production, consequently leading to abnormal metabolism of carbohydrates, lipids and proteins causing elevation of glucose in the blood. Oxidative stress, an imbalance between the production of free radicals and body antioxidant system has been implicated in the pathogenesis of diabetes. Free radicals attack important macromolecules leading to cell damage. Antioxidants are intimately involved in the prevention of damage caused by free radicals. METHODS: The anti-diabetic effects of hybrid compounds (2a-h) of thiosemicarbazone and triazole containing methoxy groups at C (4) positions were tested against genes involved in glucose metabolism (Glut-4, Mef2a and Nrf-1) using quantitative real time PCR (qPCR). Free radical scavenging capacity (FRAP, TEAC, DPPH and ORAC) of the hybrids was also carried out by using established antioxidant capacity assays. RESULTS: From the results, hybrid compounds 2b and 2h showed more pronounced effects in up-regulating diabetes associated genes which are important in the up-regulation of glucose uptake. All the hybrid compounds also showed free radical scavenging abilities. CONCLUSION: In conclusion, hybrid compounds (2b and 2h) can be useful as potential drugs for the management of diabetes mellitus.

Exercise increases hyper-acetylation of histones on the Cis-element of NRF-1 binding to the Mef2a promoter: Implications on type 2 diabetes.

Exercise brings changes on the chromatin ensuing the upregulation of many genes that confer protection from type 2 diabetes. In type-2 diabetes, critical genes are down-regulated such as those involved in glucose transport (GLUT4, MEF2A) and also oxidative phosphorylation (NRF-1 and its target genes). Recent reports have shown that NRF-1 not only regulate mitochondrial oxidative genes but also controls MEF2A, the main transcription factor for glucose transporter, GLUT4. Such dual control of the two pathways by NRF-1 place it as critical gene in the design of therapeutic modalities much needed to cure or better manage type 2 diabetes. Although it is known that NRF-1 controls these dual pathways (glucose transport and oxidative phosphorylation), the actual molecular mechanisms involved surrounding this regulation remains elusive. NRF-1 itself is regulated through posttranslational modifications (acetylation, methylation and phosphorylation) resulting in enhanced binding to its target genes. This study is therefore aimed at assessing whether CaMKII, a kinase activated by exercise brings about hyper-acetylation of histones in the vicinity of NRF-1 target gene, Mef2a. Five to six weeks old male Wistar rats were used in this study. Chromatin immunoprecipitation (ChIP) assay was used to investigate the extent through which NRF-1 is bound to the Mef2a gene and if this was associated with hyper-acetylation of histones in the region of NRF-1 binding site of the Mef2a gene. Quantitative real time PCR (qPCR) was used to determine the gene expression of MEF2A and NRF-1. Results from this study indicated that exercise-induced CaMKII activation increased hyper-acetylation of histones in the region of NRF-1 binding site on vicinity of Mef2a gene and this was associated with the increased binding of NRF-1 to Mef2a gene. Exercise also increased the expression of NRF-1 and MEF2A genes. Administration of CaMKII inhibitor (KN93) prior to exercise attenuated the observed exercise-induced increase of NRF-1 and MEF2A expressions. In conclusion, this study demonstrated for the first time in our knowledge one mechanism through which NRF-1 regulates MEF2A, pathway critical in glucose transport.

Calmodulin dependent protein kinase II activation by exercise regulates saturated & unsaturated fatty acids and improves some metabolic syndrome markers.

AIMS: Activation of Calmodulin dependent protein kinase (CaMK)-II by exercise has a plethora of benefits in health. Fatty acids play a pivotal role in the pathogenesis of metabolic syndrome (MetS). Prevention of MetS and treatment of its main characteristics are very significant to fight against type 2 diabetes. CaMKII activation in the regulation of saturated and unsaturated fatty acids in relation to type 2 diabetes and MetS has not been studied, which became the focus of this present study. MAIN METHODS: Using Gas chromatography-Mass spectrometry, we investigated saturated fatty acids and unsaturated fatty acids. Quantitative real time PCR was also used to assess the gene expression. KEY FINDINGS: Results indicate that both palmitoleic acid and oleic acid which are monounsaturated fatty acids were increased in response to CaMKII activation. On the other hand, myristic acid and palmitic acid which are saturated fatty acids known to increase the risk factors of MetS and type 2 diabetes were decreased by exercise induction of CaMKII. Conversely, lauric acid also a saturated fatty acid was increased in response to CaMKII activation by exercise. This fatty acid is known to have beneficial effects in alleviating symptoms of both type 2 diabetes and MetS. SIGNIFICANCE: According to our knowledge, this is the first study to show that CaMKII activation by exercise regulates fatty acids essential in type 2 diabetes and MetS. CaMKII can be an avenue of designing novel therapeutic drugs in the management and treatment of type 2 diabetes and MetS.

Evaluation of the Influence of thiosemicarbazone-triazole hybrids on genes implicated in lipid oxidation and accumulation as potential anti-obesity agents.

A series of thiosemicarbazone-triazole hybrids 1a-h are efficiently synthesised and evaluated for their influence on the expression of genes, cpt-1, acc-1 and pgc-1, which are essential in lipid metabolism. The test results show that hybrids 1c and 1g exhibited relatively high influence on the expression of cpt-1 and pgc-1 and suppression of acc-1 as desired.