Phenolic compounds of Hibiscus sabdariffa and influence of organic residues on its antioxidant and antitumoral properties / Compostos fenólicos de Hibiscus sabdariffa e influência de resíduos orgânicos em sua propriedade antitumoral e antioxidante

The aim of this study was to evaluate the phenolic and flavonoids contents and the antioxidant and antitumoral activity of leaf and calyx methanolic extracts from Hibiscus sabdariffa (roselle) cultivated with poultry litter and organosuper® under three modes of application. The total phenolic content in the each extract was determined using the Folin-Ciocalteu reagent and for aluminium chloride flavonoids. The antioxidant parameters were analyzed using a 2, 2-diphenyl-1-picrylhydrazyl (DPPH.) free radical scavenging assay. An antitumor colorimetric assay using sulforhodamine B. The highest contents of phenolic and flavonoids were observed in leaf extracts (389.98 and 104.52 mg g–1, respectively) and calyx extracts (474.09 and 148.35 mg g–1, respectively) from plants cultivated with organosuper®, although these values did not differ significantly from those observed for the other treatments. The average IC50 of leaves (43.48 μg mL–1) and calyces (37.15 μg mL–1) demonstrated that both have substances that may contribute to free radical scavenging action. The methanol extract from calyces showed significant selective activity against a leukemia line (K-562), with IC50 values of 0.12 mg mL–1 (organosuper®) and 1.16 mg mL–1 (poultry litter), with concentration-dependent, cytotoxic and cytocidal effects.

O objetivo deste estudo foi avaliar a atividade antioxidante, antitumoral e o conteúdo de fenólicos e flavonoides do extrato metanólico das folhas e cálices de Hibiscus sabdariffa (rosela) cultivada com cama de frango e organosuper ® em três modos de aplicação. O conteúdo fenólico total de cada extrato foi determinado utilizando o reagente de Folin-Ciocalteu e cloreto de alumínio para flavonoides. Os parâmetros antioxidantes foram avaliados pelo ensaio de seqüestro de radical livre 2, 2-difenil-1-picrilhidrazil (DPPH.). Na avaliação antitumoral utilizou-se o ensaio colorimétrico com sulforrodamina B. Observou-se o maior conteúdo de fenólicos e flavonoides em extratos de folhas (389.98 e 104.52 mg g–1, respectivamente) e extratos de cálice (474.09 e 148.35 mg g–1, respectivamente) de plantas cultivadas com organosuper ®, embora esses valores não diferiram significativamente daqueles observados para os outros tratamentos. O IC50 de folhas (43.48 µg mL–1) e cálices (37.15 µg mL–1) demonstrou que ambos têm substâncias que podem contribuir para a ação seqüestradora de radicais livres. O extrato metanólico dos cálices mostrou seletividade na linhagem de leucemia (K-562), com valores de IC50 de 0,12 mg mL–1 (organosuper®) e 1,16 mg mL–1 (cama-de-frango) com concentração-dependente e efeito citotóxico e citocida.

Neutralising antibodies for Mayaro virus in Pantanal, Brazil

The Pantanal hosts diverse wildlife species and therefore is a hotspot for arbovirus studies in South America. A serosurvey for Mayaro virus (MAYV), eastern (EEEV), western (WEEV) and Venezuelan (VEEV) equine encephalitis viruses was conducted with 237 sheep, 87 free-ranging caimans and 748 equids, including 37 collected from a ranch where a neurologic disorder outbreak had been recently reported. Sera were tested for specific viral antibodies using plaque-reduction neutralisation test. From a total of 748 equids, of which 264 were immunised with vaccine composed of EEEV and WEEV and 484 had no history of immunisation, 10 (1.3%) were seropositive for MAYV and two (0.3%) for VEEV using criteria of a ≥ 4-fold antibody titre difference. Among the 484 equids without history of immunisation, 48 (9.9%) were seropositive for EEEV and four (0.8%) for WEEV using the same criteria. Among the sheep, five were sero- positive for equine encephalitis alphaviruses, with one (0.4%) for EEEV, one (0.4%) for WEEV and three (1.3%) for VEEV. Regarding free-ranging caimans, one (1.1%) and three (3.4%), respectively, had low titres for neutralising antibodies to VEEV and undetermined alphaviruses. The neurological disorder outbreak could not be linked to the alphaviruses tested. Our findings represent strong evidence that MAYV and all equine encephalitis alphaviruses circulated in the Pantanal.

The protective effect of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes

OBJECTIVES: The aim of this study was to investigate the protective effects of aqueous extracts of roselle (Hibiscus sabdariffa L. UKMR-2) against red blood cell (RBC) membrane oxidative stress in rats with streptozotocin-induced diabetes. METHODS: Forty male Sprague-Dawley rats weighing 230-250 g were randomly divided into four groups (n = 10 rats each): control group (N), roselle-treated control group, diabetic group, and roselle-treated diabetic group. Roselle was administered by force-feeding with aqueous extracts of roselle (100 mg/kg body weight) for 28 days. RESULTS: The results demonstrated that the malondialdehyde levels of the red blood cell membranes in the diabetic group were significantly higher than the levels in the roselle-treated control and roselle-treated diabetic groups. The protein carbonyl level was significantly higher in the roselle-treated diabetic group than in the roselle-treated control group but lower than that in the diabetic group. A significant increase in the red blood cell membrane superoxide dismutase enzyme was found in roselle-treated diabetic rats compared with roselle-treated control rats and diabetic rats. The total protein level of the red blood cell membrane, osmotic fragility, and red blood cell morphology were maintained. CONCLUSION: The present study demonstrates that aqueous extracts of roselle possess a protective effect against red blood cell membrane oxidative stress in rats with streptozotocin-induced diabetes. These data suggest that roselle can be used as a natural antioxidative supplement in the prevention of oxidative damage in diabetic patients. .

Hypolipidemic activity of Hibiscus rosa sinensis root in rats.

The hypolipidemic activity of Hibiscus rosa sinensis (family Malvaceae) root extract was studied on triton and cholesterol-rich high fat diet (HFD) induced models of hyperlipidemia in rats. In triton WR-1339-induced hyperlipidemia, feeding with root extract (500 mg/kg body wt/day p.o.) exerted lipid-lowering effect, as assessed by reversal of plasma levels of total cholesterol (TC), phospholipids (PL) and triglycerides (TG) and reactivation of post-heparin lipolytic activity (PHLA) of plasma. The other model was fed with cholesterol-rich HFD and root extract (500 mg/kg body wt/ day p.o.) simultaneously for 30 days. This also caused lowering of lipid levels in plasma and liver homogenate and reactivation of plasma PHLA and hepatic total lipoprotein lipase activity. The hypolipidemic activity of Hibiscus rosa sinensis root was compared with a standard drug guggulipid (200 mg/kg body wt/day p.o.), a known lipid- lowering agent in both models. Histopathological findings in rat liver supported the protective role of H. rosa sinensis root extract in preventing cholesterol-rich HFD-induced hepatic steatosis.

Antioxidant and antihyperlipidemic activity of Hibiscus sabdariffa Linn. leaves and calyces extracts in rats.

Antioxidant and antihyperlipidemic activities of the extracts of leaves and calyces of Hibiscus sabdariffa were investigated by studying their in vitro inhibitory activity on lipid peroxidation and in vivo effects on cholesterol induced hyperlipidemia. Highest antioxidant activity was exhibited by ethanolic extract of calyces followed by ethanolic extract of leaves followed by aqueous extract of leaves of H. sabdariffa. In cholesterol induced hyperlipidemic model, groups of rats treated with extracts of calyces and leaves of H. sabdariffa showed a significant decrease in the serum TC, LDL-C, VLDL-C, TAG values alongwith an increase in serum HDL-C levels. The treated groups also showed significant decrease in the atherogenic index, LDL-C: HDL-C risk ratios, and in the levels of SGOT, SGPT and ALP activities compared to cholesterol induced hyperlipidemic control group. Significant antihyperlipidemic activity was shown by ethanolic extract of calyces, followed by ethanolic extract of leaves. It was observed from the histopathological findings that rats fed with H. sabdariffa extracts showed decrease in granular degeneration caused by cholesterol feedings. Results suggest that the ethanolic extracts of calyces and leaves of H. sabdarifa containing polyphenols and flavanols possess significant antioxidant and antihyperlipidemic activities.

A study of the staining effect of roselle (Hibiscus sabdariffa) on the histologic section of the testis

This study describes the preparation and use of Roselle (Hibiscus sabddariffa) for the differential staining of testicular tissue sections to find out its staining effect on nuclear, cytoplasmic and other structures. Various treatments using modifications of the plant extract in water were carried out on sections of the rabbit testis. Various levels of differentiation of nuclear and cytoplasmic structures as well as other structures of this organ was obtained especially when 1 percent eosin was applied as a counter stain. The best staining result was obtained when iron alum was used to mordant the extract and when the extract, mordanted with potassium alum was acidified using acetic acid and used to stain the sections. Modification of the aqueous extract to an alkaline pH using ammonia gave the poorest staining effect. Roselle extract therefore shows reasonable potential as a candidate nuclear stain especially when modanted with iron alum or mordanted with potassium alum and acidified with acetic acid.

Este estudio describe la preparación y utilización de Roselle (Hibiscus sabddarifa) en la tinción diferencial de cortes histológicos de tejido testicular, para conocer su efecto sobre la tinción nuclear, citoplasmática y otras estructuras. Diversos tratamientos utilizando modificaciones de extracto de la planta en el agua, se llevaron a cabo en cortes de testículos de conejo. Distintos niveles de diferenciación de las estructuras nucleares y citoplasmáticas, así como de otras estructuras de este órgano, se han obtenido principalmente cuando se utiliza como tinción eosina al 1 por ciento. El mejor resultado de tinción se obtuvo cuando se utilizó alumbre de hierro y cuando éste fue acidificado con ácido acético y se usó para teñir los cortes histológicos. La modificación del extracto acuoso a un pH alcalino utilizando amoníaco, dio una coloración más débil. El extracto de rosa de Jamaica muestra un razonable potencial para tinción nuclear, especialmente, cuando es mezclado con alumbre de hierro o aluminio de potasio y acidificada con ácido acético.