Antioxidant and antiproliferative activities of non-edible parts of selected tropical fruits

It is of interest that seeds and pericarps of tropical fruits contain phytochemicals being the components of various biological activities for beneficial health effects. This study was aimed to evaluate antioxidant and anticancer activities of the methanolic extracts from seeds and pericarps of three selected tropical fruits including Rambutan (Nephelium lappaceum L.), Litchi (Litchi chinensis Sonn.) and Tamarind (Tamarindus indica L.). Total phenolic content was determined by using the Folin-Ciocalteu method. Antioxidant capacity was evaluated based on the ability of the fruit extracts to scavenge ABTS and DPPH radicals. MTT reduction assay and Annexin V-FITC/PI staining were carried out for cytotoxicity and apoptosis induction, respectively. Total phenolic contents of the seeds and pericarps of the tropical fruits ranged from 104.60 to 501.95 mg/g DW. All extracts were found to have significant antioxidant activities. Among them, tamarind seed extract contained the highest total phenolic contents and possessed the highest antioxidant capacities. Tamarind seed extract showed the highest cytotoxicity to human mouth carcinoma (CLS-354) cells and had no toxicity to PBMCs. Staining with annexin V-FITC/PI showed that this apoptosis occurred early in this cell type with 10.0% of the cells undergoing apoptosis. Tamarind seed extract might have potential anticancer activity which could be attributed, in part, to selectively inhibit the growth of CLS-354 cells and induce apoptosis. This research finding would be valuable information to identify major constituents of the extracts and mechanisms underlying anticancer activity which could be attributed to dietary health supplements or cancer chemoprevention from fruits

ANTI-RADICAL ACTIVITIES OF XANTHONES AND FLAVONOIDS FROM GARCINIA SCHOMBURGKIANA

Objective: The present study aimed to isolate and identify the phytochemical constituents of Garcinia schomburgkiana branches and evaluate the antioxidant activity of the compounds.Methods: The chromatographic and spectroscopic (UV, IR, NMR and MS) techniques were used for the isolation and elucidation of the compounds, respectively. The antioxidant activity of the isolated compounds was examined through DPPH, ABTS, nitric oxide and hydroxyl radical scavenging assay.Results: The (-)-5,7,3′,5′-tetrahydroxyflavanone (1), which was firstly found in the Garcinia species, together with kaempferol (2), (-)-dihydrokaempferol (3), euxanthone (4), gentisein (5) and norathyriol (6) were isolated from G. schomburgkiana. Among the isolated compounds, compound 1 and 6 exhibited the highest potential for anti-radical activities.Conclusion: Compound 1 could be used as the chemotaxonomic marker of G. schomburgkiana. The branches of G. schomburgkiana could be the alternative source of the antioxidants. The possible inhibitory mechanisms were proposed through the action of electron transfer, chelation, and nitrosylation.Â

Study designs to investigate Nox1 acceleration of neoplastic progression in immortalized human epithelial cells by selection of differentiation resistant cells

To investigate the role of NADPH oxidase homolog Nox1 at an early step of cell transformation, we utilized human gingival mucosal keratinocytes immortalized by E6/E7 of human papillomavirus (HPV) type 16 (GM16) to generate progenitor cell lines either by chronic ethanol exposure or overexpression with Nox1. Among several cobblestone epithelial cell lines obtained, two distinctive spindle cell lines – FIB and NuB1 cells were more progressively transformed exhibiting tubulogenesis and anchorage-independent growth associated with increased invasiveness. These spindle cells acquired molecular markers of epithelial mesenchymal transition (EMT) including mesenchymal vimentin and simple cytokeratins (CK) 8 and 18 as well as myogenic alpha-smooth muscle actin and caldesmon. By overexpression and knockdown experiments, we showed that Nox1 on a post-translational level regulated the stability of CK18 in an ROS-, phosphorylation- and PKCepilon-dependent manner. PKCepilon may thus be used as a therapeutic target for EMT inhibition. Taken together, Nox1 accelerates neoplastic progression by regulating structural intermediate filaments leading to EMT of immortalized human gingival epithelial cells

Malondialdehyde as a Useful Biomarker of Low Hand Grip Strength in Community-Dwelling Stroke Patients

The assessment of muscle strength by hand grip strength (HGS) is used to evaluate muscle weakness and wasting among stroke patients. This study aimed to investigate the association of oxidative stress/oxidative damage and inflammatory biomarkers with muscle strength and wasting, as evaluated by HGS, among community-dwelling post-stroke patients. The HGS of both paretic and non-paretic limbs was negatively associated with modified Rankin scale (mRS) values. The serum levels of catalase activity and malondialdehyde (MDA), and plasma tumor necrosis factor (TNF)-α levels were significantly increased in post-stroke patients compared with non-stroke controls. Further analysis highlighted that hydrogen peroxide was positively correlated with HGS in the paretic limbs. Interestingly, an elevated MDA level, excluding advanced age and high mRS, increased the risk of low HGS in the non-paretic limbs of stroke patients. This study suggests that there is a detrimental association between MDA and muscle strength and early muscle wasting among post-stroke patients. Hence, MDA is a potentially useful biomarker of muscle weakness and wasting in post-stroke patients living in the community