Nur Kartinee Kassim

Antioxidant activity-guided separation of coumarins and lignan from Melicope glabra (Rutaceae)

The ethyl acetate and methanol bark extracts of Melicope glabra were evaluated for their antioxidant capacities by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and β-carotene bleaching/linoleic acid system. Both extracts exhibited strong inhibition against the DPPH radical (IC50 values of 24.81 and 13.01 μg ml(-1), respectively) and strong antioxidant activity in β-carotene bleaching assay. Both samples were found to have high phenolic content with values of 39 and 44 mg GAE/g as indicated by Follin-Ciocalteaus reagent. Antioxidant TLC assay-guided isolation on the methanol extract led to the isolation of a new pyranocoumarin, glabranin (1), umbelliferone (2), scopoletin (3) and sesamin (4), and their structures were determined by spectroscopy. Compounds (1-3) showed significant activities on DPPH free radical with the IC50 of 240.20, 810.02 and 413.19 μg ml(-1), respectively. However, in β-carotene bleaching assay, sesamin (4) showed higher inhibitory activity (1 mg ml(-1), 95%) than glabranin (1) (1 mg ml(-1), 74%), whilst umbelliferone (2) and scopoletin (3) were slightly pro-oxidant.

Xanthorrhizol: a review of its pharmacological activities and anticancer properties

Xanthorrhizol (XNT) is a bisabolane-type sesquiterpenoid compound extracted from Curcuma xanthorrhiza Roxb. It has been well established to possess a variety of biological activities such as anticancer, antimicrobial, anti-inflammatory, antioxidant, antihyperglycemic, antihypertensive, antiplatelet, nephroprotective, hepatoprotective, estrogenic and anti-estrogenic effects. Since many synthetic drugs possess toxic side effects and are unable to support the increasing prevalence of disease, there is significant interest in developing natural product as new therapeutics. XNT is a very potent natural bioactive compound that could fulfil the current need for new drug discovery. Despite its importance, a comprehensive review of XNT’s pharmacological activities has not been published in the scientific literature to date. Here, the present review aims to summarize the available information in this area, focus on its anticancer properties and indicate the current status of the research. This helps to facilitate the understanding of XNT’s pharmacological role in drug discovery, thus suggesting areas where further research is required.

Two New Xanthones from Calophyllum nodusum (Guttiferae)

The air-dried powdered stem bark of Calophyllum nodusum (Guttiferea) collected from Sandakan (Sabah, Malaysia), was extracted sequentially with hexane, chloroform and methanol. The solvents were removed by rotary evaporator to give dark viscous extracts. Detailed and repeated chromatographic separation of the extracts lead to isolation of two new xanthones, identified as nodusuxanthone (1a) and trapezifolixanthone A (2). Other common terpenoids such as betulinic acid, lupeol, stigmasterol and friedelin were also isolated from the extracts and identified. The structures of the compounds were established by detailed spectral analysis and comparison with previously reported data.

Crude Extracts, Flavokawain B and Alpinetin Compounds from the Rhizome of Alpinia mutica Induce Cell Death via UCK2 Enzyme Inhibition and in Turn Reduce 18S rRNA Biosynthesis in HT-29 Cells

Uridine-cytidine kinase 2 is an enzyme that is overexpressed in abnormal cell growth and its implication is considered a hallmark of cancer. Due to the selective expression of UCK2 in cancer cells, a selective inhibition of this key enzyme necessitates the discovery of its potential inhibitors for cancer chemotherapy. The present study was carried out to demonstrate the potentials of natural phytochemicals from the rhizome of Alpinia mutica to inhibit UCK2 useful for colorectal cancer. Here, we employed the used of in vitro to investigate the effectiveness of natural UCK2 inhibitors to cause HT-29 cell death. Extracts, flavokawain B, and alpinetin compound from the rhizome of Alpinia mutica was used in the study. The study demonstrated that the expression of UCK2 mRNA were substantially reduced in treated HT-29 cells. In addition, downregulation in expression of 18S ribosomal RNA was also observed in all treated HT-29 cells. This was confirmed by fluorescence imaging to measure the level of expression of 18S ribosomal RNA in live cell images. The study suggests the possibility of MDM2 protein was downregulated and its suppression subsequently activates the expression of p53 during inhibition of UCK2 enzyme. The expression of p53 is directly linked to a blockage of cell cycle progression at G0/G1 phase and upregulates Bax, cytochrome c, and caspase 3 while Bcl2 was deregulated. In this respect, apoptosis induction and DNA fragmentation were observed in treated HT-29 cells. Initial results from in vitro studies have shown the ability of the bioactive compounds of flavokawain B and alpinetin to target UCK2 enzyme specifically, inducing cell cycle arrest and subsequently leading to cancer cell death, possibly through interfering the MDM2-p53 signalling pathway. These phenomena have proven that the bioactive compounds could be useful for future therapeutic use in colon cancer.

Clausenidin from Clausena excavata induces apoptosis in hepG2 cells via the mitochondrial pathway

ETHNOPHARMACOLOGICAL RELEVANCE Clausena excavata Burm.f. is used locally in folk medicine for the treatment of cancer in South East Asia. AIM OF THE STUDY To determine the mechanism of action of pure clausenidin crystals in the induction of hepatocellular carcinoma (hepG2) cells apoptosis. MATERIALS AND METHODS Pure clausenidin was isolated from Clausena excavata Burm.f. and characterized using 1H and 13C NMR spectra. Clausenidin-induced cytotoxicity was determined by MTT assay. The morphology of hepG2 after treatment with clausenidin was determined by fluorescence and Scanning Electron Microscopy. The effect of clausenidin on the apoptotic genes and proteins were determined by real-time qPCR and protein array profiling, respectively. The involvement of the mitochondria in clausenidin-induced apoptosis was investigated using MMP, caspase 3 and 9 assays. RESULTS Clausenidin induced significant (p<0.05) and dose-dependent apoptosis of hepG2 cells. Cell cycle assay showed that clausenidin induced a G2/M phase arrest, caused mitochondrial membrane depolarization and significantly (p<0.05) increased expression of caspases 3 and 9, which suggest the involvement of the mitochondria in the apoptotic signals. In addition, clausenidin caused decreased expression of the anti-apoptotic protein, Bcl 2 and increased expression of the pro-apoptotic protein, Bax. This finding was confirmed by the downregulation of Bcl-2 gene and upregulation of the Bax gene in the treated hepG2 cells. CONCLUSION Clausenidin extracted from Clausena excavata Burm.f. is an anti-hepG2 cell compound as shown by its ability to induce apoptosis through the mitochondrial pathway of apoptosis. Clausenidin can potentially be developed into an anticancer compound.

Clausenidin induces caspase-dependent apoptosis in colon cancer

BackgroundClausena excavata Burm.f. is a shrub traditionally used to treat cancer patients in Asia. The main bioactive chemical components of the plant are alkaloids and coumarins. In this study, we isolated clausenidin from the roots of C. excavata to determine its apoptotic effect on the colon cancer (HT-29) cell line.MethodWe examined the effect of clausenidin on cell viability, ROS generation, DNA fragmentation, mitochondrial membrane potential in HT-29 cells. Ultrastructural analysis was conducted for morphological evidence of apoptosis in the treated HT-29 cells. In addition, we also evaluated the effect of clausenidin treatment on the expression of caspase 3 and 9 genes and proteins in HT-29 cells.ResultClausenidin induced a G0/G1 cell cycle arrest in HT-29 cells with significant (p < 0.05) dose-dependent increase in apoptotic cell population. The DNA fragmentation assay also showed apoptotic features in the clausenidin-treated HT-29 cells. Clausenidin treatment had caused significant (p < 0.05) increases in the expression of caspase 9 protein and gene in HT-29 cells and mitochondrial ROS and mitochondrial membrane depolarization. The results suggest the involvement of the mitochondria in the caspase-dependent apoptosis in clausenidin-treated colon cancer cells.ConclusionClausenidin induces a caspase-dependent apoptosis in colon cancers through the stimulation of the mitochondria. The study demonstrates the potential of clausenidin for use in the treatment of colon cancers.

Clausenidin Induces Caspase 8-Dependent Apoptosis and Suppresses Production of VEGF in Liver Cancer Cells

Clausena excavata Burm f. is used by traditional healers to treat cancer patients in South East Asia. The use of the plant and its compounds is based on Asian folklore with little or no scientific evidence supporting the therapeutic efficacy The current study aimed to determine the effect of pure clausenidin isolated from C. excavata on caspase-8-induced cell death as well as angiogenesis in the HepG2 hepatocellular carcinoma cell line. Caspase-8 and extrinsic death receptor protein expression was determined using spectrophotometry and protein profile arrays, respectively. Ultrastructural analysis of clausenidin-treated cells was conducted using transmission electron microscopy. In addition, anti-angiogenic effects of clausenidin were investigated by Western blot analysis. Clausenidin significantly (p<0.05) increased the activity of caspase-8 and expression of protein components of the death inducing signaling complex (DISC) in HepG2 cells. Ultrastructural analysis of the clausenidin-treated HepG2 cells revealed morphological abnormalities typical of apoptosis. Furthermore, clausenidin significantly (p<0.05) decreased the expression of vascular endothelial growth factor (VEGF). Therefore, clausenidin is a potential anti-angiogenic agent which may induce apoptosis of hepatocellular carcinoma cells.

Antioxidant properties of ginger (Kaempferia angustifolia Rosc.) and its chemical markers

ABSTRACT The nutritional value of the rhizomes of Kaempferia angustifolia was measured through the antioxidant properties of various extracts and the determination of the bioactive compounds. The chloroform and methanol extracts of the rhizomes of Kaempferia angustifolia showed strong free radical scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) with values of 615.92 mg Trolox equivalent (TE)/g each. The methanol extract also exhibited the strongest antioxidant properties in the azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS) assay with a value of 38.87 mg TE/g. The hexane extract gave the strongest reducing ability in cupric reducing antioxidant capacity (CUPRAC) assay with a value of 901.76 mg TE/g, whilst the ethyl acetate extract exhibited the strongest reducing ability against ferric reducing antioxidant power (FRAP) with a value of 342.23 mg TE/g. Column chromatographic separation on the rhizomes of Kaempferia angustifolia afforded boesenboxide (1), crotepoxide (2), 2ˊ-hydroxy-4,4ˊ,6ˊ-trimethoxychalcone (3), kaempfolienol (4), and zeylenol (5), which were elucidated by spectroscopic methods. Kaempfolienol (4) was the strongest free radical agent against DPPH with a value of 443.92 mg TE/g, whilst 2ˊ-hydroxy-4,4ˊ,6ˊ-trimethoxychalcone (3) exhibited the strongest antioxidant properties with values of 42.23, 1497.22, and 781.53 mg TE/g against ABTS, CUPRAC, and FRAP assays, respectively.

Measurement of Antioxidant Activity and Structural Elucidation of Chemical Constituents from Aglaia oligophylla Miq.

Aglaia oligophylla Miq. is a shrub of approximately 25 meters tall under the Meliaceae family which possess distinct pharmacological properties including insecticides, anti-inflammatory and anticancer. The purpose of this study is to evaluate the antioxidant capacity of the trunks and stem of Aglaia oligophylla plant extracts and to isolate their chemical constituents. The antioxidant activity was evaluated as the reducing antioxidant capacity includes of cupric reducing antioxidant capacity (CUPRAC) and ferric reducing antioxidant power (FRAP) assays. In CUPRAC assay, ethyl acetate extract of the trunks part exhibited the strongest reducing capacity with the value of 1543 mg Trolox equivalent (TE)/g and for the stem part, methanol extract showed the strongest reducing antioxidant capacity with the value of 1059 mg TE/g. In FRAP assay, the methanol extracts of both trunks and stem of the plant showed the strongest reducing power with the values of 1269 mg TE/g and 1084 mg TE/g respectively. Repeated column chromatographic separation on chloroform extract of the trunks part afforded one triterpenes which was suggested to be stigmasterol (1) whilst the separation on methanol extract of the trunks obtained a triterpene, β-sitosterol (2). In the stem of A. oligophylla, the column chromatographic separation on petroleum ether extract afforded a new triterpene, namely oligophyllic acid (3) while the separation on chloroform and ethyl acetate extracts gave compound 2. All the chemical constituents were elucidated by comparison with literature review reported previously. Based on the value of CUPRAC and FRAP antioxidant assays of the plant extracts, A. oligophylla, shows great potential for the possibility of discovery and development of health promoting supplement from the extracts and chemical constituents.

Isolation of antioxidative compounds from Micromelum minutum guided by preparative thin layer chromatography-2,2-diphenyl-1-picrylhydrazyl (PTLC-DPPH) bioautography method

The application of preparative thin layer chromatography-2,2-diphenyl-1-picrylhydrazyl (PTLC-DPPH) bioautography technique successfully isolated a lignan sesamin (1), two prenylated coumarins (2 and 3) and a marmesin glycosides (4) from Micromelum minutum methanol bark extract. Compounds 2 and 3 were identified as new compounds whereas 1 and 4 were first isolated from Micromelum genus. Structural identification of all compounds were done by detailed spectroscopic analyses and comparison with literature data. Antioxidant capacities of extract, active fraction and compounds were measured based on DPPH free radical savenging activity, oxygen radical absorbance capacity (ORAC) and β-carotene bleaching. The DPPH activity of methanol extract and its fraction present the IC50 values of 54.3 and 168.9 µg/mL meanwhile the β-carotene bleaching results were 55.19% and 5.75% respectively. The ORAC measurements of M. minutum extract, compounds 2 and 4 showed potent antioxidant activity with the values of 5123, 5539 and 4031 µmol TE/g respectively.