Cucurbitacin L 2-O-ß-Glucoside Demonstrates Apoptogenesis in Colon Adenocarcinoma Cells (HT-29): Involvement of Reactive Oxygen and Nitrogen Species Regulation.

Emerging evidence suggests that reactive oxygen (ROS) and nitrogen (RNS) species can contribute to diverse signalling pathways of inflammatory and tumour cells. Cucurbitacins are a group of highly oxygenated triterpenes. Many plants used in folk medicine to treat cancer have been found to contain cucurbitacins displaying potentially important anti-inflammatory actions. The current study was designed to investigate the anti-ROS and -RNS effects of cucurbitacin L 2-O-ß-glucoside (CLG) and the role of these signaling factors in the apoptogenic effects of CLG on human colon cancer cells (HT-29). This natural cucurbitacin was isolated purely from Citrullus lanatus var. citroides (Cucurbitaceae). The results revealed that CLG was cytotoxic to HT-29. CLG increased significantly (P < 0.05) RNA and protein levels of caspase-3 in HT-29 cells when verified using a colorimetric assay and realtime qPCR, respectively. The results showed that lipopolysaccharide/interferon-gamma (LPS/INF-γ) increased nitrous oxide (NO) production inR AW264.7macrophages, whereas N(G)-nitro-L-argininemethyl ester (L-NAME) and CLG curtailed it. This compound did not reveal any cytotoxicity on RAW264.7 macrophages and human normal liver cells (WRL-68) when tested using the MTT assay. Findings of ferric reducing antioxidant power (FRAP) and oxygen radical absorption capacity (ORAC) assays demonstrate the antioxidant properties of CLG. The apoptogenic property of CLG on HT-29 cells is thus related to inhibition of reactive nitrogen and oxygen reactive species and the triggering of caspase-3-regulated apoptosis.

Antioxidant activity of different parts from Annona squamosa, and Catunaregam nilotica methanolic extract.

BACKGROUND: We extracted phenolic compounds from Annona squamosa (leaves, bark, roots and seedcake), and Catunaregam nilotica (leaves, bark and seedcake) using methanol and their antioxidant activity was evaluated employing various established in vitro systems. MATERIAL AND METHODS: Annona squamosa (leaves, bark, roots and seedcake), and Catunaregam nilotica (leaves, bark and seedcake) were used in the study. Antioxidant activity was estimated using oxygen radical absorbance capacity, MTT assay and DPPH assays, and polyphenols profile was determined by HPLC method. RESULTS: The total phenolic content was determined by Folin-Ciocalteu method and the highest amounts were 171.5, 170.4, 169.5, and 167.9 g/kg plant extract as GAE for A. squamosa roots, C. nilotica bark, C. nilotica leaves, and A. squamosa bark, respectively. The leaves extracts of the two trees showed high flavoniod content. The results showed that C. nilotica and A. squamosa extracts displayed antioxidant activities, with IC(50) values ranging from 7.81 to 62.5 and from 7.81 to 125.0 µg/ml, respectively using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay. The different parts extracts from two trees showed good antioxidant activity evaluated by oxygen radical absorbance capacity and MTT assay systems. CONCLUSION: These results suggested that Annona squamosa and Catunaregam nilotica phenolic compounds could be utilized as a natural antioxidant.

Anti-inflammatory activities of cucurbitacin E isolated from Citrullus lanatus var. citroides: role of reactive nitrogen species and cyclooxygenase enzyme inhibition.

The in vivo and in vitro mechanistic anti-inflammatory actions of cucurbitacin E (CE) (Citrullus lanatus var. citroides) were examined. The results showed that LPS/INF-γ increased NO production in RAW264.7 macrophages, whereas L-NAME and CE curtailed it. CE did not reveal any cytotoxicity on RAW264.7 and WRL-68 cells. CE inhibited both COX enzymes with more selectivity toward COX-2. Intraperitoneal injection of CE significantly suppressed carrageenan-induced rat's paw edema. ORAC and FRAP assays showed that CE is not a potent ROS scavenger. It could be concluded that CE is potentially useful in treating inflammation through the inhibition of COX and RNS but not ROS.

Rossinones A and B, biologically active meroterpenoids from the Antarctic ascidian, Aplidium species.

Rossinones A (1) and B (2), biologically active meroterpene derivatives, were isolated from an Antarctic collection of the ascidian Aplidium species and structurally characterized with spectroscopic methods. The absolute configuration of 1 was deduced by using the modified Mosher method. The rossinones exhibit anti-inflammatory, antiviral and antiproliferative activities.