Chemopreventive effect of Phaleria macrocarpa on colorectal cancer aberrant crypt foci in vivo.

ETHNOPHARMACOLOGICAL RELEVANCE: Natural products are important ingredients for pharmaceutical applications specifically new entities for treating cancer and other diseases. Phaleria macrocarpa is native of Indonesia and considered as a prolific source of bioactive substances useful for chemoprevention. AIM OF THE STUDY: To investigate the chemopreventive properties of Phaleria macrocarpa on azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rats. METHODS: The biological activities of the ethanol extract of P. macrocarpa fruits were evaluated both in vitro and in vivo. First the extract was investigated for its in vitro antioxidant activity by the total phenolic content and ferric reducing antioxidant power assay. Then the chemopreventive effect of P. macrocarpa was performed on AOM-induced aberrant crypt foci as colorectal carcinoma model in rats. RESULT: the crude ethanolic extract of P. macrocarpa has high antioxidant activity and modulated the oxidative stress as proved by the up-regulation of glutathione-s-transferase and superoxide dismutase. Immunohistochemical staining of the treated sections showed overexpression of PCNA and Bax, reduced crypt sizes and numbers, indicating the characteristic feature of apoptotic cancer cells. PCNA is a landmark of cell damage and turn-over and can be associated with clinical cancer mutation. The most potent doses were 250mg/kg and 500mg/kg as compared to 35mg/kg 5-fluorouracil. CONCLUSION: In this sense, the potential modulation of the colorectal pathophysiological pathway by P. macrocarpa natural compounds mostly flavonoids offer a great possibility for the discovery of new leads towards the colorectal cancer.

Andrographis paniculata leaf extract prevents thioacetamide-induced liver cirrhosis in rats.

This study investigated the hepatoprotective effects of ethanolic Andrographis paniculata leaf extract (ELAP) on thioacetamide-induced hepatotoxicity in rats. An acute toxicity study proved that ELAP is not toxic in rats. To examine the effects of ELAP in vivo, male Sprague Dawley rats were given intraperitoneal injections of vehicle 10% Tween-20, 5 mL/kg (normal control) or 200 mg/kg TAA thioacetamide (to induce liver cirrhosis) three times per week. Three additional groups were treated with thioacetamide plus daily oral silymarin (50 mg/kg) or ELAP (250 or 500 mg/kg). Liver injury was assessed using biochemical tests, macroscopic and microscopic tissue analysis, histopathology, and immunohistochemistry. In addition, HepG2 and WRL-68 cells were treated in vitro with ELAP fractions to test cytotoxicity. Rats treated with ELAP exhibited significantly lower liver/body weight ratios and smoother, more normal liver surfaces compared with the cirrhosis group. Histopathology using Hematoxylin and Eosin along with Masson's Trichrome stain showed minimal disruption of hepatic cellular structure, minor fibrotic septa, a low degree of lymphocyte infiltration, and minimal collagen deposition after ELAP treatment. Immunohistochemistry indicated that ELAP induced down regulation of proliferating cell nuclear antigen. Also, hepatic antioxidant enzymes and oxidative stress parameters in ELAP-treated rats were comparable to silymarin-treated rats. ELAP administration reduced levels of altered serum liver biomarkers. ELAP fractions were non-cytotoxic to WRL-68 cells, but possessed anti-proliferative activity on HepG2 cells, which was confirmed by a significant elevation of lactate dehydrogenase, reactive oxygen species, cell membrane permeability, cytochrome c, and caspase-8,-9, and, -3/7 activity in HepG2 cells. A reduction of mitochondrial membrane potential was also detected in ELAP-treated HepG2 cells. The hepatoprotective effect of 500 mg/kg of ELAP is proposed to result from the reduction of thioacetamide-induced toxicity, normalizing reactive oxygen species levels, inhibiting cellular proliferation, and inducing apoptosis in HepG2 cells.

Chemoprevention of colonic aberrant crypt foci by Gynura procumbens in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Gynura procumbens is commonly used as a traditional medicinal plant in Malaysia for treatment of many diseases. To investigate the chemopreventive properties of Gynura procumbens on azoxymethane (AOM)-induced aberrant crypt foci (ACF) in rats. METHODS: Five groups of adult male rats were used in this experiment. Normal/control group; the rats were injected subcutaneously with 15 mg/kg of sterile normal saline once a week for two weeks, and orally administered with 10% Tween 20 (5 mL/kg). Carcinogen and treatment groups; the rats were injected subcutaneously each with 15 mg/kg body weight AOM once a week for 2 weeks and were continued to be fed for two months, respectively with 10% Tween 20, 500 and 250mg/kg body weight plant extracts. Reference group; the rats were injected subcutaneously with 15 mg/kg body weight AOM once a week for 2 weeks, and injected intraperitoneally with fluorouracil 35 mg/kg body weight for five consecutive days. RESULT: Total ACF detected in methylene blue stained whole mounts of rat colon were 21, 23and 130 in rats fed with 500, 250 mg/kg body weight treatment and carcinogen groups, respectively. Treatment with high and low doses of the plant extract led to83.6% and 82.2% decrease in the total crypts in the groups fed 500 mg/kg and 250 mg/kg Gynura procumbens respectively compared to carcinogen group. Immunohistochemical staining of ACF showed suppressed azoxymethane induced colonic cell proliferation and Bcl-2 expression. Glutathione-S-transfarase and superoxide dismutase activities were higher in treated rats compared to carcinogen groups. CONCLUSION: Gynura procumbens reduced the incidence of AOM induced ACF. The findings showed that Gynura procumbens may have antiproliferative and antioxidative properties. Moreover, Gynura procumbens possesses the medicinal properties to prevent colon cancer.

Antioxidant and pro-oxidant effects of oil palm (Elaeis guineensis) leaves extract in experimental diabetic nephropathy: a duration-dependent outcome.

BACKGROUND: Catechins-rich oil palm (Elaeis guineensis) leaves extract (OPLE) is known to have antioxidant activity. Several polyphenolic compounds reported as antioxidants such as quercetin, catechins and gallic acid have been highlighted to have pro-oxidant activity at high doses. Therefore, the present study was conducted to investigate the antioxidant and pro-oxidant effects of chronically administering high dose of OPLE (1000 mg kg⁻¹) in an animal model of diabetic nephropathy (DN). METHODS: Animal body weight, indexes of glycaemia, renal function and morphology were assessed in diabetic animals with and without OPLE (1000 mg kg⁻¹) for 4 and 12 weeks respectively. Oxidative stress was quantified by measuring levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), lipid peroxides (LPO) and reduced glutathione (GSH). Transforming growth factor-beta1 (TGF-ß1), a key mediator of extracellular matrix accumulation, was analysed in plasma. The mechanisms of OPLE action were evaluated by assessing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits (p22phox and p67phox) expression. RESULTS: Oral administration with high dose of catechins-rich OPLE (1000 mg kg⁻¹) to STZ-induced diabetic rats for 4 weeks attenuated renal dysfunction (hyperfiltration, proteinuria) and development of glomerulosclerosis and tubulointerstitial fibrosis, features that are associated with DN. Suppression of increases in oxidative stress markers (8-OHdG, LPO) and the fibrotic cytokine, TGF-ß1 was observed. OPLE also reduced renal expression of NADPH oxidase subunits p22phox and p67phox. In contrast and surprisingly, identical dose of OPLE when administered to diabetic animals for 12 weeks caused worsening of renal dysfunction, histopathology in addition to further elevation of oxidative stress marker (LPO) and TGF-ß1. These unfavourable effects of prolonged treatment with 1000 mg kg⁻¹ OPLE were accompanied by increase expression of one of the NADPH oxidase subunits, p22phox. CONCLUSION: Our study indicates that chronic administration of 1000 mg kg-1 OPLE exerts both antioxidant and pro-oxidant effects in DN depending on the duration of treatment. The present study also reveals that the antioxidant/pro-oxidant effects of OPLE are in part, due to modulation of NADPH activity.

In vivo evaluation of ethanolic extract of Zingiber officinale rhizomes for its protective effect against liver cirrhosis.

Zingiber officinale is a traditional medicine against various disorders including liver diseases.The aim of this study was to assess the hepatoprotective activity of the ethanolic extract of rhizomes of Z. officinale (ERZO) against thioacetamide-induced hepatotoxicity in rats. Five groups of male Sprague Dawley have been used. In group 1 rats received intraperitoneal (i.p.) injection of normal saline while groups 2-5 received thioacetamide (TAA, 200 mg/kg; i.p.) for induction of liver cirrhosis, thrice weekly for eight weeks. Group 3 received 50 mg/kg of silymarin. The rats in groups 4 and 5 received 250 and 500 mg/kg of ERZO (dissolved in 10% Tween), respectively. Hepatic damage was assessed grossly and microscopically for all of the groups. Results confirmed the induction of liver cirrhosis in group 2 whilst administration of silymarin or ERZO significantly reduced the impact of thioacetamide toxicity. These groups decreased fibrosis of the liver tissues. Immunohistochemistry assessment against proliferating cell nuclear antigen did not show remarkable proliferation in the ERZO-treated rats when compared with group 2. Moreover, factions of the ERZO extract were tested on Hep-G2 cells and showed antiproliferative activity (IC50 38-60 µ g/mL). This study showed hepatoprotective effect of ERZO.

Chronic Administration of Oil Palm (Elaeis guineensis) Leaves Extract Attenuates Hyperglycaemic-Induced Oxidative Stress and Improves Renal Histopathology and Function in Experimental Diabetes.

Oil palm (Elaeis guineensis) leaves extract (OPLE) has antioxidant properties and because oxidative stress contributes to the pathogenesis of diabetic nephropathy (DN), we tested the hypothesis that OPLE prevents diabetes renal oxidative stress, attenuating injury. Sprague-Dawley rats received OPLE (200 and 500 mg kg(-1)) for 4 and 12 weeks after diabetes induction (streptozotocin 60 mg kg(-1)). Blood glucose level, body and kidney weights, urine flow rate (UFR), glomerular filtration rate (GFR), and proteinuria were assessed. Oxidative stress variables such as 8-hydroxy-2'-deoxyguanosine (8-OHdG), glutathione (GSH), and lipid peroxides (LPO) were quantified. Renal morphology was analysed, and plasma transforming growth factor-beta1 (TGF-ß1) was measured. Diabetic rats demonstrated increase in blood glucose and decreased body and increased kidney weights. Renal dysfunction (proteinuria, elevations in UFR and GFR) was observed in association with increases in LPO, 8-OHdG, and TGF-ß1 and a decrease in GSH. Histological evaluation of diabetic kidney demonstrated glomerulosclerosis and tubulointerstitial fibrosis. OPLE attenuated renal dysfunction, improved oxidative stress markers, and reduced renal pathology in diabetic animals. These results suggest OPLE improves renal dysfunction and pathology in diabetes by reducing oxidative stress; furthermore, the protective effect of OPLE against renal damage in diabetes depends on the dose of OPLE as well as progression of DN.

Uterotrophic, fetotoxic and abortifacient effect of a Malaysian variety of Plumbago rosea L. on isolated rat uterus and pregnant mice.

Traditionally Plumbago rosea L. is used as an abortifacient in the Southeast Asian region. Methanolic root extract of a local species of Plumbago rosea L. was studied to evaluate its traditional antifertility claim. Interestingly, it was found to possess dose related inhibitory effect on uterine contractile responses elicited by oxytocic agents on isolated uteri of pregnant and pseudo-pregnant rats. Furthermore, it was found to possess significant (p < 0.05) fetotoxic activity along with mild abortive potential in pregnant mice when given orally at high doses (400 and 800 mg kg(-1)) once daily for ten days starting from day 10 of gestation. The results derived indicated possible presence of utero-active compound (s) in this plant that inhibited oxytocic agents induced uterine motility. Moreover, pronounced fetotoxic and mild abortifacient potentials observed at higher doses in pregnant mice might support its accredited traditional use to avoid unwanted pregnancy.