Xylocarpus Moluccensis Induces Cytotoxicity in Human Hepatocellular Carcinoma HepG2 Cell Line via Activation of the Extrinsic Pathway.

OBJECTIVE: Liver cancer is one of the most common causes of cancer death, with reduced survival rates. The development of new chemotherapeutic agents is essential to find effective cytotoxic drugs that give minimum side effects to the surrounding healthy tissues. The main objective of the present study was to evaluate the cytotoxic effects and mechanism of cell death induced by the crude and diethyl ether extract of Xylocarpus mouccensis on the human hepatocellular carcinoma cell line. METHODS: The cytotoxicity activity was measured using the MTS assay. The mode of cell death determined by the apoptosis study, DNA fragmentation analysis done by using the TUNEL system. The pathway study or mechanism of apoptosis observed by study caspases 8, 9, 3/7 Glo-caspases method. RESULTS: In this study, the methanol extracts prepared from leaf Xylocarpus mouccensis leaf produced cytotoxicity effect with IC50 (72hr) < 30µg/ml. The IC50 value at 72 hours exerted by diethyl ether extract of Xylocarpus moluccensis leaf was 0.22 µg/ml, which was more cytotoxic than to that of crude methanol extract. The results obtained by the colorimetric TUNEL system suggest that methanol crude extract of Xylocarpus moluccensis (leaf), diethyl ether extract of Xylocarpus moluccensis (leaf) and methanol extract of Xylocarpus granatum (bark) induced DNA fragmentation in the HepG2 cell line. Besides, the caspase-Glo assay demonstrated that diethyl ether leaf extract of Xylocarpus moluccensis triggered apoptotic cell death via activation of caspases -8, and -3/7 However, no visible activation was noticed for caspase -9. Furthermore, TLC indicates the presence of potential metabolites in an extract of Xylocarpus moluccensis. CONCLUSION: Thus, the present study suggests the remarkable potential of active metabolites in the extract of Xylocarpus moluccensis as a future therapeutic agent for the treatment of cancer.
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Acute application of Centella asiatica extract enhanced AMPAR-mediated postsynaptic currents in rat entorhinal cortex.

Centella asiatica is notable for its wide range of biological activities beneficial to human health, particularly its cognitive enhancement and neuroprotective effects. The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors are ionotropic glutamate receptors mediating fast excitatory neurotransmission essential in long-term potentiation widely thought to be the cellular mechanism of learning and memory. The method of whole-cell patch-clamp was used to study the effect of the acute application of Centella asiatica extract on the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor-mediated spontaneous excitatory postsynaptic currents in the entorhinal cortex of rat brain slices. The respective low dose of test compounds significantly increased the amplitude of spontaneous excitatory postsynaptic currents while having no significant effects on the frequency. The findings suggested that Centella asiatica extract increased the response of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors at the postsynaptic level, revealing the potential role of Centella asiatica in modulating the glutamatergic responses in the entorhinal cortex of rat brain slices to produce cognitive enhancement effects.

Antihypercholesterolemic and antiatherosclerotic potencies of Pandanus tectorius fruits via increasing scavenger receptor-B1 genes expression and inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity.

Atherosclerosis is a leading cause of death worldwide. The adverse side effects of currently available drugs urge to find more effective and safe remedial agents. Alternative candidates from natural resources are of great consequence in the emerging of new drugs. Pandanus tectorius (Pandanaceae) was traditionally used in Ayurvedic medicine to cure certain diseases. Thus, the current study conducted to elucidate the potency of P. tectorius fruit as antiatherosclerosis and antihypercholesterolemia agents through the regulation of high density lipoprotein (HDL) receptor (scavenger receptor [SR]-B1) gene expression and 3-hydroxy-3-methylglutaryl coenzyme A reductase reductase (HMGCR) in vitro, respectively. The P. tectorius fruit was noncytotoxic against the HepG2 cell line confirmed by 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyl tetrazolium bromide assay. The P. tectorius fruit successfully upregulates the SR-B1 gene expression and downregulate the HMGCR. Moreover, an in vivo study showed that P. tectorius has good activity on the upregulation of HDL and subsequently downregulation of total cholesterol level. Moreover, P. tectorius fruit did not show any increase in toxicity biomarkers serum glutamic oxaloacetic transaminase and serum glutamate pyruvate transaminase in vivo. These results found that P. tectorius fruits have potency as the preventive agent for hypercholesterolemia and atherosclerosis via SR-B1 and HMGCR mechanisms of action.

Differential expression of entorhinal cortex and hippocampal subfields α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptors enhanced learning and memory of rats following administration of Centella asiatica.

Centella asiatica (CA) is a widely used traditional herb, notably for its cognitive enhancing effect and potential to increase synaptogenesis. The α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) and N-methyl-D-aspartate receptors (NMDARs) mediate fast excitatory neurotransmission with key roles in long-term potentiation which is believed to be the cellular mechanism of learning and memory. Improved learning and memory can be an indication to the surface expression level of these receptors. Our previous study demonstrated that administration of CA extract improved learning and memory and enhanced expression of AMPAR GluA1 subunit while exerting no significant effects on GABAA receptors of the hippocampus in rats. Hence, to further elucidate the effects of CA, this study investigated the effects of CA extract in recognition memory and spatial memory, and its effects on AMPAR GluA1 and GluA2 subunit and NMDAR GluN2 A and GluN2B subunit expression in the entorhinal cortex (EC) and hippocampal subfields CA1 and CA3. The animals were administered with saline, 100 mg/kg, 300 mg/kg, and 600 mg/kg of CA extract through oral gavage for 14 days, followed by behavioural analysis through Open Field Test (OFT), Novel Object Recognition Task (NORT), and Morris Water Maze (MWM) and lastly morphological and immunohistochemical analysis of the surface expression of AMPAR and NMDAR subunits were performed. The results showed that 14 days of administration of 600 mg/kg of CA extract significantly improved memory assessed through NORT while 300 mg/kg of CA extract significantly improved memory of the animals assessed through MWM. Immunohistochemical analysis revealed differential modulation effects on the expressions of receptor subunits across CA1, CA3 and EC. The CA extract at the highest dose (600 mg/kg) significantly enhanced the expression of AMPAR subunit GluA1 and GluA2 in CA1, CA3 and EC, and NMDAR subunit GluN2B in CA1 and CA3 compared to control. At 300 mg/kg, CA significantly increased expression of AMPAR GluA1 in CA1 and EC, and GluA2 in CA1, CA3 and EC while 100 mg/kg of CA significantly increased expression of only AMPAR subunit GluA2 in CA3 and EC. Expression of NMDAR subunit GluN2 A was significantly reduced in the CA3 (at 100, 300, and 600 mg/kg) while no significant changes of subunit expression was observed in CA1 and EC compared to control. The results suggest that the enhanced learning and memory observed in animals administered with CA was mainly mediated through increased expression of AMPAR GluA1 and GluA2 subunits and differential expression of NMDAR GluN2 A and GluN2B subunits in the hippocampal subfields and EC. With these findings, the study revealed a new aspect of cognitive enhancing effect of CA and its therapeutic potentials through modulating receptor subunit expression.

Hippocampal amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid GluA1 (AMPA GluA1) receptor subunit involves in learning and memory improvement following treatment with Centella asiatica extract in adolescent rats.

INTRODUCTION: Centella asiatica is an herbal plant that contains phytochemicals that are widely believed to have positive effects on cognitive function. The adolescent stage is a critical development period for the maturation of brain processes that encompass changes in physical and psychological systems. However, the effect of C. asiatica has not been extensively studied in adolescents. The aim of this study was therefore to investigate the effects of a C. asiatica extract on the enhancement of learning and memory in adolescent rats. METHODS: The locomotor activity, learning, and memory were assessed by using open field test and water T-maze test. This study also examined changes in neuronal cell morphology using cresyl violet and apoptosis staining. We also performed immunohistochemical study to analyse the expression of the glutamate AMPA receptor (α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) GluA1 subunit and the GABA receptor (γ-Aminobutyric Acid) subtype GABAA α1 subunit in the hippocampus of the same animals. RESULTS: We found no significant changes in locomotor activity (p > 0.05). The water T-maze data showed that 30 mg/kg dose significantly (p < 0.05) improved learning, memory, and the memory consolidation phase but had no effect on reversal learning (p > 0.05). Histological data revealed no neuronal morphological changes. Immunohistochemical analysis revealed increased expression of the AMPA GluA1 receptor subunit but there was no effect on GABAA receptor α1 subunit expression in the CA1 and CA2 subregions of the hippocampus. CONCLUSIONS: The C. asiatica extract therefore improved hippocampus-dependent spatial learning and memory in a dose-dependent manner in rats through the GluA1-containing AMPA receptor in the CA1 and CA2 sub regions of the hippocampus.

The Effects of 4-Hydroxybenzoic Acid Identified from Bamboo (Dendrocalamus asper) Shoots on Kv1.4 Channel.

BACKGROUND: Bamboo shoot has been used as a treatment for epilepsy in traditional Chinese medicine for generations to treat neuronal disorders such as convulsive, dizziness and headaches. 4-hydroxybenzoic acid (4-hba) is a non-flavonoid phenol found abundantly in Dendrocalamus asper shoots (bamboo), fruits (strawberries and apples) and flowers. Kv1.4 is a rapidly inactivating Shaker-related member of the voltage-gated potassium channels with two inactivation mechanisms; the fast N-type and slow C-type. It plays vital roles in repolarisation, hyperpolarisation and signaling the restoration of resting membrane potential through the regulation of the movement of K+ across the cellular membrane. METHODS: Chemical compounds from Dendrocalamus asper bamboo shoots were purified and identified as major palmitic acids mixed with other minor fatty acids, palmitic acid, 4-hydroxybenzaldehyde, lauric acid, 4-hydroxybenzoic acid and cholest-4-ene-3-one. The response of synthetic 4-hydroxybenzoic acid was tested on Kv1.4 potassium channel which was injected into viable oocytes that was extracted from Xenopus laevis. The current were detected by the two-microelectrode voltage clamp, holding potential starting from -80 mV with 20 mV step-up until +80 mV. Readings of treatments with 0.1% DMSO, 4-hba concentrations and K channel blockers were taken at +60 mV. The ratio of tail/peak amplitude is the index of the activity of the Kv1.4 channels with n ≥ 6 (number of oocytes tested). The decreases of the ratios of five different concentrations (1 µM, 10 µM, 100 µM, 1 mM and 2.5 mM) were compared with 0.1% DMSO as the control. RESULTS: All concentration showed statistically significant results with P < 0.05 except for 100 µM. The normalised current of the 4-hba concentrations were compared with potassium channel blockers (TEA and 4-AP) and all groups showed statistically significant results. This study also showed that time taken for each concentration to affect Kv1.4 does not play any significant roles. CONCLUSION: 4-hydroxybenzoic acid was found to be able to enhance the inactivation of Kv1.4 by lowering the membrane potential so that the abnormal neuronal firing can be inhibited. With IC50 slightly higher than 10 µM, increasing concentrations (100 µM, 1 mM and 2.5 mM) had shown to exhibit toxicity effects. The best concentration from this study is 10 µM with Hill slope of 0.1799.

Phaleria macrocarpa Boerl. (Thymelaeaceae) leaves increase SR-BI expression and reduce cholesterol levels in rats fed a high cholesterol diet.

In vitro and in vivo studies of the activity of Phaleria macrocarpa Boerl (Thymelaeaceae) leaves against the therapeutic target for hypercholesterolemia were done using the HDL receptor (SR-BI) and hypercholesterolemia-induced Sprague Dawley rats. The in vitro study showed that the active fraction (CF6) obtained from the ethyl acetate extract (EMD) and its component 2',6',4-trihydroxy-4'-methoxybenzophenone increased the SR-BI expression by 95% and 60%, respectively. The in vivo study has proven the effect of EMD at 0.5 g/kgbw dosage in reducing the total cholesterol level by 224.9% and increasing the HDL cholesterol level by 157% compared to the cholesterol group. In the toxicity study, serum glutamate oxalate transaminase (SGOT) and serum glutamate pyruvate transaminase (SGPT) activity were observed to be at normal levels. The liver histology also proved no toxicity and abnormalities in any of the treatment groups, so it can be categorized as non-toxic to the rat liver. The findings taken together show that P. macrocarpa leaves are safe and suitable as an alternative control and prevention treatment for hypercholesterolemia in Sprague Dawley rats.

Cytotoxic aaptamines from Malaysian Aaptos aaptos.

In a preliminary screen, Aaptos aaptos showed significant cytotoxic activity towards a panel of cell lines and was thus subjected to bioassay-guided isolation of the bioactive constituents. In addition to the known aaptamine, two new derivatives of the alkaloid were isolated from the bioactive chloroform fraction of the crude methanolic extract. Detailed analysis by NMR and mass spectroscopy enabled their identification to be 3-(phenethylamino)demethyl(oxy)aaptamine and 3-(isopentylamino)demethyl(oxy) aaptamine. The cytotoxic activities of the three alkaloids were further evaluated against CEM-SS cells.

Antioxidative constituents of Etlingera elatior.

Phytochemical studies on the rhizomes of Etlingera elatior have resulted in the isolation of 1,7-bis(4-hydroxyphenyl)-2,4,6-heptatrienone (1), demethoxycurcumin (2), 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one (3), 16-hydroxylabda-8(17),11,13-trien-15,16-olide (4), stigmast-4-en-3-one, stigmast-4-ene-3,6-dione, stigmast-4-en-6beta-ol-3-one, and 5alpha,8alpha-epidioxyergosta-6,22-dien-3beta-ol. Compounds 1 and 4 are new, and their structures were elucidated by analysis of spectroscopic data. Diarylheptanoids 1-3 were found to inhibit lipid peroxidation in a more potent manner than alpha-tocopherol.