Mohamad Roji Sarmidi

Flavonoids and phenolic acids from Labisia pumila (Kacip Fatimah)

Both total phenolic content (TPC) and total flavonoid content (TFC) of Labisia pumila extracts were determined spectrophotometrically. L. pumila leaves extracted in 60% methanol (MeOH) were fractionated on C18 cartridge and the antioxidant property of each fraction was determined by measuring free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity. The 40% MeOH fraction exhibited the highest scavenging activity. Nine flavonols (quercetin, myricetin and kaempferol), two flavanols (catechin and epigallocatechin) and nine phenolic acids were identified from this active fraction by UPLC-ESI-MS/MS, and confirmed by comparison with the mass spectra of standard aglycones, theoretical fragments generated from MS Fragmenter software, and literature values.

Multi-elemental composition and physical properties of honey samples from Malaysia.

The elemental profiles of six honey samples from Malaysia had been constructed using the data obtained from both ICP-AES and ICP-MS. Potassium and sodium were the most abundant minerals covering from 69.3-78.6% and 14.1-28.7%, respectively. The ratio of potassium to sodium was more than one. Even though the minerals and trace elements composition varied dependent on the type of honey samples, there was no statistically significant difference between the analysed honey samples, namely tualang, gelam, acacia and a few forest honeys based on two-factor ANOVA and cluster analysis. The total element content of honey samples were strongly correlated with the electrical conductivity, but only have moderate correlation with the ash content and honey colour based on the regression analysis. PCA result on the available elemental data from worldwide honeys, including honey samples from Malaysia revealed that potassium and sodium were the mineral markers to distinguish honey origin. Both tualang and gelam honey samples from Malaysia have close mineral profile with sesame honeys from Egypt and multifloral honeys from India, whereas forest honeys Malaysia were near to avocado honeys from Spain and multifloral honeys from India.

Mitochondrial dysfunction as a central event for mechanisms underlying insulin resistance: the roles of long chain fatty acids

Insulin resistance is characterized by hyperglycaemia, dyslipidaemia and oxidative stress prior to the development of type 2 diabetes mellitus. To date, a number of mechanisms have been proposed to link these syndromes together, but it remains unclear what the unifying condition that triggered these events in the progression of this metabolic disease. There have been a steady accumulation of data in numerous experimental studies showing the strong correlations between mitochondrial dysfunction, oxidative stress and insulin resistance. In addition, a growing number of studies suggest that the raised plasma free fatty acid level induced insulin resistance with the significant alteration of oxidative metabolism in various target tissues such as skeletal muscle, liver and adipose tissue. In this review, we herein propose the idea of long chain fatty acid‐induced mitochondrial dysfunctions as one of the key events in the pathophysiological development of insulin resistance and type 2 diabetes. The accumulation of reactive oxygen species, lipotoxicity, inflammation‐induced endoplasmic reticulum stress and alterations of mitochondrial gene subset expressions are the most detrimental that lead to the developments of aberrant intracellular insulin signalling activity in a number of peripheral tissues, thereby leading to insulin resistance and type 2 diabetes. Copyright

Ficus deltoidea (Mas cotek) extract exerted anti-melanogenic activity by preventing tyrosinase activity in vitro and by suppressing tyrosinase gene expression in B16F1 melanoma cells

Ficus deltoidea (Mas cotek) water extract has been widely used for woman health in Malaysia. Our investigation focused to identify anti-melanogenic efficacy of F. deltoidea since it has been known to have strong anti-oxidant activities. Anti-melanogenic effect of F. deltoidea extract was analyzed using cultured B16F1 melanoma cells. Cytotoxicity of the extract was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and determined the highest concentration of the extract that did not affect cell viability as 0.1% (w/v). α-MSH-induced melanin synthesis was significantly inhibited with dose-dependent manner by treatment of F. deltoidea leave extract, which was comparable to that of kojic acid. The extract directly inhibited mushroom tyrosinase activity and intracellular tyrosinase activity of B16F1 as well. The inhibition of intracellular tyrosinase activity was found to be exerted at the protein expression level when analyzed by immunoblot and tyrosinase zymography. The expression of microphthalmia-associated transcription factor (MITF) was also reduced by the F. deltoidea extract. In conclusion, F. deltoidea extract has strong anti-melanogenic activity that is exerted by direct inhibition of tyrosinase enzyme activity and by down-regulation of the expression of genes involved in the melanogenesis pathways. Collectively, data shown in this study strongly suggest that F. deltoidea extract has potential to be used as a novel depigmenting agent for cosmetics.

Review on Labisia pumila (Kacip Fatimah): bioactive phytochemicals and skin collagen synthesis promoting herb.

Labisia pumila is a traditional herb widely used as post-partum medication for centuries. Recently, extensive researches have been carried out on the phytochemical identification, biological and toxicological studies for the herb. Phytochemicals found in the herbal extract showed high antioxidant properties, which were essential for various pharmacological activities. The significant findings are anti-estrogenic deficiency and -immunodeficiency diseases. Another finding that has considerable impact on natural product research is the contribution of L. pumila in promoting skin collagen synthesis. The performance of the herb as anti-aging agent due to natural aging process and accelerated by UV radiation was reviewed critically.

Mitochondrial dysfunction as a central event for mechanisms underlying insulin resistance

Insulin resistance is characterized by hyperglycaemia, dyslipidaemia and oxidative stress prior to the development of type 2 diabetes mellitus. To date, a number of mechanisms have been proposed to link these syndromes together, but it remains unclear what the unifying condition that triggered these events in the progression of this metabolic disease. There have been a steady accumulation of data in numerous experimental studies showing the strong correlations between mitochondrial dysfunction, oxidative stress and insulin resistance. In addition, a growing number of studies suggest that the raised plasma free fatty acid level induced insulin resistance with the significant alteration of oxidative metabolism in various target tissues such as skeletal muscle, liver and adipose tissue. In this review, we herein propose the idea of long chain fatty acid‐induced mitochondrial dysfunctions as one of the key events in the pathophysiological development of insulin resistance and type 2 diabetes. The accumulation of reactive oxygen species, lipotoxicity, inflammation‐induced endoplasmic reticulum stress and alterations of mitochondrial gene subset expressions are the most detrimental that lead to the developments of aberrant intracellular insulin signalling activity in a number of peripheral tissues, thereby leading to insulin resistance and type 2 diabetes. Copyright

Modeling of glucose regulation and insulin-signaling pathways

A model of glucose regulation system was combined with a model of insulin-signaling pathways in this study. A feedback loop was added to link the transportation of glucose into cells (by GLUT4 in the insulin-signaling pathways) and the insulin-dependent glucose uptake in the glucose regulation model using the Michaelis-Menten kinetic model. A value of K(m) for GLUT4 was estimated using Genetic Algorithm. The estimated value was found to be 25.3 mM, which was in the range of K(m) values found experimentally from in vivo and in vitro human studies. Based on the results of this study, the combined model enables us to understand the overall dynamics of glucose at the systemic level, monitor the time profile of components in the insulin-signaling pathways at the cellular level and gives a good estimate of the K(m) value of glucose transportation by GLUT4. In conclusion, metabolic modeling such as displayed in this study provides a good predictive method to study the step-by-step reactions in an organism at different levels and should be used in combination with experimental approach to increase our understanding of metabolic disorders such as type 2 diabetes.

Citric acid concentration by electrodialysis: ion and water transport modelling

The work in this paper was aimed at the study of the ion transport behaviour of citrate ion through ion exchange membranes. A mathematical model to represent the ion and water transport behaviour of an electrodialysis (ED) process for concentrating citric acid under the influence of different current density was developed. This model is valid for any ED process with ion exchange membranes used under a similar operating condition. The value for the phenomenological coefficients is different for other types of membranes and solutes. The corresponding phenomenological coefficients have to be determined experimentally. The reliability of developed ion and water transport model was assessed through comparison with the experimental data. The results obtained showed that the developed ion and water transport model was in good agreement with the experimental data and it could be used to predict the performance of ED for citric acid concentration.

LC–MS/MS-based metabolites of Eurycoma longifolia (Tongkat Ali) in Malaysia (Perak and Pahang)

A number of three LC-MS/MS hybrid systems (QTof, TripleTof and QTrap) has been used to profile small metabolites (m/z 100-1000) and to detect the targeted metabolites such as quassinoids, alkaloids, triterpene and biphenylneolignans from the aqueous extracts of Eurycoma longifolia. The metabolite profiles of small molecules showed four significant clusters in the principle component analysis for the aqueous extracts of E. longifolia, which had been collected from different geographical terrains (Perak and Pahang) and processed at different extraction temperatures (35°C and 100°C). A small peptide of leucine (m/z 679) and a new hydroxyl methyl β-carboline propionic acid have been identified to differentiate E. longifolia extracts that prepared at 35°C and 100°C, respectively. From the targeted metabolites identification, it was found that 3,4ɛ-dihydroeurycomanone (quassinoids) and eurylene (squalene-type triterpene) could only be detected in the Pahang extract, whereas canthin-6-one-3N-oxide could only be detected in the Perak extract. Overall, quassinoids were present in the highest concentration, particularly eurycomanone and its derivatives compared to the other groups of metabolites. However, the concentration of canthin-6-one and β-carboline alkaloids was significantly increased when the roots of the plant samples were extracted at 100°C.

Cytotoxicity of Aqueous and Ethanolic Extracts of Ficus deltoidea on Human Ovarian Carcinoma Cell Line

Aims : This study was to investigate the cytotoxicity of both plant extracts from Ficus deltoidea (locally known as Mas Cotek), aqueous and ethanolic extracts on human ovarian carcinoma cells using standard colometric MTT assay. Study design: Cell based assay