Comparative anti-inflammatory properties of Capsaicin and ethyl-aAcetate extract of Capsicum frutescens linn [Solanaceae] in rats.

BACKGROUND: The analgesic effect of capsaicin (the active ingredient in Capsicum frutescens Linn. [Solanaceae]) had been reported in several studies. Current research is being directed at producing analgesics, anti-inflammatory agents with better side effect profile. OBJECTIVES: To investigate if either the ethyl acetate extract of Capsicum frutescens Linn. [Solanaceae] (CFE) or capsaicin (Fluka Biotechnika-CPF) (in addition to the known analgesic properties) has any anti-inflammatory effect comparable to nonsteroidal anti-inflammatory analgesics (NSAIDS). METHODS: The effects of ethyl acetate extract of Capsicum frutescens Linn. [Solanaceae] (CFE) and capsaicin (Fluka Biotechnika-CPF) was examined on rat hind paw. Inflammation was induced in the rat's hind paw by subplantar injections of fresh egg albumin (0.5 ml/kg). Diclofenac (100 mg/kg) was used as the reference anti-inflammatory agent for comparison, while distilled water was used as the placebo. The leucocytes count, corticosterone and C - reactive protein (CRP) levels were measured as biomarkers of inflammation. Data obtained were pooled and analysed using repeated ANOVA, in a general linear model with the CPSS software. RESULTS: Sub-plantar injections of fresh egg albumin (0.5 ml/kg) produced profound and time-related oedema in the rat hind paw of the 'control' rats. Diclofenac (DIC, 100 mg/kg, i.p.) and reference capsaicin (CPF, 2.5 mg/kg, i.p.) significantly inhibited paw swelling at (p<0.05-0.001) (CI 95%) compared to distilled water-treated 'controls'. While the corticosterone levels were all very low in 7 rats treated with capsaicin, the leucocytes count was within normal range in 9 rats. However, in 16 specimens randomly assigned for CRP levels, there were very high CRP readings, up to a magnitude of 10 times the normal range. CONCLUSIONS: Capsaicin in both forms (CFE and CPF) produced anti-inflammatory effects that were comparable to diclofenac in the experimental rat model at p<0.05. It may be concluded that capsaicin has both analgesic and anti-inflammatory properties.

Effects of Ficus exasperata vahl. (moraceae) leaf aqueous extract on the renal function of streptozotocin-treated rats.

The present study was undertaken to evaluate the possible reno-protective effect of Ficus exasperata leaf aqueous extract (FEE) in a rat experimental paradigm of diabetes mellitus. Forty Wistar rats (weighing 200-230 g) were divided into four (A, B, C, and D) groups, each group consisting of 10 rats. Group A rats served as 'control' animals and received citrate buffer (pH 6.3) solution in quantities equivalent to intraperitoneally-administered volumes of streptozotocin (STZ) and FEE. Diabetes mellitus was induced in Groups B and C rats by intraperitoneal injections of STZ (75 mg/kg). Group C rats were additionally treated with FEE (100 mg/kg/day, p.o.) 4 weeks post STZ injections, for 4 consecutive weeks. Group D rats received FEE (100 mg/kg/day p.o.) only for 4 weeks. Post-euthanisation, kidney tissues were excised for histopathological evaluation and processed for light microscopy. Plasma malondialdehyde and tissue nitric oxide were determined. Serum creatinine, blood urea nitrogen, nitrite, and albumin concentrations were measured for the evaluation of renal function. The diabetic rats significantly lost more weight and their blood glucose levels were significantly elevated as compared to the 'control' group of animals. Renal dysfunction was evidenced by kidney hypertrophy, decreased renal blood flow, and increased serum creatinine and nitrite concentrations. Furthermore, vascular dysfunction, as evidenced by decreased carotid blood flow, was observed in the diabetic rats. FEE treatment positively ameliorated the alterations in the biochemical variables in the STZ + FEE-treated rats. In conclusion, our findings suggest that FEE treatment ameliorates STZ-induced nephrotoxicity.

The grapefruit: an old wine in a new glass? Metabolic and cardiovascular perspectives.

Grapefruit is a popular, tasty and nutritive fruit enjoyed globally. Biomedical evidence in the last 10 years has, however, shown that consumption of grapefruit or its juice is associated with drug interactions, which, in some cases, have been fatal. Grapefruit-induced drug interactions are unique in that the cytochrome P450 enzyme CYP3A4, which metabolises over 60% of commonly prescribed drugs as well as other drug transporter proteins such as P-glycoprotein and organic cation transporter proteins, which are all expressed in the intestines, are involved. However, the extent to which grapefruit-drug interactions impact on clinical settings has not been fully determined, probably because many cases are not reported. It has recently emerged that grapefruit, by virtue of its rich flavonoid content, is beneficial in the management of degenerative diseases such as diabetes and cardiovascular disorders. This potentially explosive subject is reviewed here.

Antipyretic and antinociceptive properties of Mentha longifolia Huds. (Lamiaceae) leaf aqueous extract in rats and mice.

The antipyretic and antinociceptive properties of Mentha longifolia Huds. (Lamiaceae) leaf aqueous extract were investigated using lipopolysaccharide (LPS)-induced pyrexia in rats, and acetic acid and hot plate analgesia tests in mice. Pentoxifylline, paracetamol and morphine were used as standard drugs for comparison. M. longifolia leaf aqueous extract and pentoxifylline (37.5-150 mg/kg i.p.) significantly (P < 0.05-0.02) reduced the LPS (50 g/kg i.m.)-elicited pyrexia. Pentoxifylline (50 mg/kg i.p.) also significantly (P < 0.01) reduced LPS (50 g/kg i.m.)-induced pyrexia. M. longifolia leaf aqueous extract (6.25-100 mg/kg i.p.) and paracetamol (500 mg/kg i.p.) profoundly inhibited the writhes produced by 3% acetic acid. Furthermore, the plant extract (25-400 mg/kg i.p.) and morphine (10 mg/kg i.p.) significantly (P < 0.001) delayed the hot plate reaction time in mice. The LD(50) values for oral and intraperitoneal administration of the plant extract were > 3200 mg/kg and 1730 mg/kg, respectively. Phytochemical analysis revealed the presence of flavonoids, saponins, tannins, reducing sugars, cardiac glycosides and triterpene steroids in the leaves of M. longifolia. These data indicate that M. longifolia leaf aqueous extract has antipyretic and antinociceptive properties. Furthermore, the relatively high LD(50) values obtained for oral and intraperitoneal administration of the plant extract demonstrate that the plant extract is non-toxic to mice.

Cardiovascular effects of mollic acid glucoside, a 1alpha-hydroxycycloartenoid saponin extractive from Combretum molle R Br ex G Don (Combretaceae) leaf.

The cardiovascular effects of mollic acid glucoside (MAG), a 1alpha-hydroxycycloartenoid saponin extractive from Combretum molle R Br ex G Don (Combretaceae) leaf, have been investigated in some experimental animal paradigms. The plant extract (MAG, 5-80 microg/ml) produced concentration-dependent, significant (p < 0.05-0.001) negative inotropic and negative chronotropic effects on guinea pig isolated electrically driven left, and spontaneously beating right atrial muscle preparations, respectively. MAG also significantly reduced (p < 0.05-0.001) or abolished, in a concentration-dependent manner, the rhythmic, spontaneous contractions of portal veins isolated from healthy, normal Wistar rats. Like acetylcholine (ACh, 10-(8)-10-(5) M), the plant extract (5-80 microg/ml) produced concentration-related relaxations of rat isolated endothelium-containing thoracic aortic rings pre-contracted with noradrenaline (NA, 10-10(-10)-(5) M). The vasorelaxant effects of MAG in the aortic rings were markedly inhibited or annulled by N(G)-nitro-L-arginine methyl ester (L-NAME, 10(-5) M), a nitric oxide synthase inhibitor. Furthermore, MAG (2.5-40 mg/kg iv) caused dose-related, transient but significant reductions (p < 0.05-0.001) in the systemic arterial blood pressures and heart rates of anaesthetised normotensive and hypertensive rats. The results of this laboratory animal study indicate that MAG caused bradycardia, vasorelaxation and hypotension in the mammalian experimental models used. The vasorelaxant action of MAG was endothelium dependent, and was therefore possibly dependent on the synthesis and release of nitric oxide (NO). The findings of this study suggest that Combretum molle leaf may be used as a natural supplementary remedy in essential hypertension and in certain cases of cardiac dysfunctions in rural African communities.

Effects of Persea americana Mill (Lauraceae) ["Avocado"] ethanolic leaf extract on blood glucose and kidney function in streptozotocin-induced diabetic rats and on kidney cell lines of the proximal (LLCPK1) and distal tubules (MDBK).

Extracts of Persea americana Mill (Lauraceae) ("Avocado") have been traditionally used to treat hypertension and diabetes mellitus. Accordingly, we studied the hypoglycaemic and renal function effects of P. americana leaf ethanolic extracts (PAE) in STZ-induced diabetic rats. Oral glucose tolerance responses to various doses of PAE were monitored in fasted rats following a glucose load. Rats treated with deionized water or standard hypoglycaemic drugs acted as untreated and treated positive controls, respectively. Acute renal effects of PAE were investigated in anesthetized rats challenged with 0.077 M NaCl after a 3.5-h equilibration for 4 h comprising 1 h control, 1.5 h treatment and 1.5 h recovery periods. PAE was added to the infusate during the treatment period. Hepatic glycogen concentration was measured after 6 weeks of daily treatment with PAE. PAE induced dose-dependent hypoglycaemic responses in STZ-induced diabetic rats while subchronic PAE treatment additionally increased hepatic glycogen concentrations. Acute PAE infusion decreased urine flow and electrolyte excretion rates, whilst subchronic treatment reduced plasma creatinine and urea concentrations. These results indicate not only the basis of the ethnomedicinal use of P. americana leaf extract in diabetes management, but also of need for further studies to identify and evaluate the safety of PAE's bioactive compounds.

Analgesic, anti-inflammatory and hypoglycaemic effects of Securidaca longepedunculata (Fresen.) [Polygalaceae] root-bark aqueous extract.

The present study was undertaken to investigate the analgesic, anti-inflammatory and hypoglycaemic properties of Securidaca longepedunculata (Fresen.) root-bark aqueous extract (SLE) in mice and rats. The analgesic effect of SLE was evaluated by 'hot-plate' and 'acetic acid' analgesic test methods in mice; while its anti-inflammatory and hypoglycaemic effects were examined in rats, using fresh egg albumin-induced pedal oedema, and streptozotocin (STZ)-induced diabetes mellitus models. Morphine (MPN, 10 mg/kg), diclofenac (DIC, 100 mg/kg) and chlorpropamide (250 mg/kg) were used as reference drugs for comparison. SLE (50-800 mg/kg i. p.) produced dose-dependent, significant (p < 0.05-0.001) analgesic effects against thermally- and chemically-induced nociceptive pain in mice. The plant's extract (SLE, 50-800 mg/kg p. o.) also dose-dependently and significantly inhibited (p < 0.05-0.001) fresh egg albumin-induced acute inflammation, and caused significant hypoglycaemia (p < 0.05-0.001) in normal (normoglycaemic) and STZ-treated diabetic (hyperglycaemic) rats. The results of this experimental animal study indicate that S. longepedunculata root-bark aqueous extract (SLE) possesses analgesic, anti-inflammatory and hypoglycaemic properties. These findings lend pharmacological credence to the anecdotal, folkloric and ethnomedical uses of S. longepedunculata root-bark in the treatment, management and/or control of painful, arthritic, inflammatory conditions, as well as in the management and/or control of type 2 diabetes mellitus in some rural communities of South Africa.

Effects of Ficus thonningii (Blume) [Morarceae] stem-bark ethanolic extract on blood glucose, cardiovascular and kidney functions of rats, and on kidney cell lines of the proximal (LLC-PK1) and distal tubules (MDBK).

Previous observations indicate that Ficus thonningii (Blume) [Moraceae] stem-bark extracts may be useful in the control of diabetes mellitus. Accordingly, we investigated in some experimental animal paradigms the effects of F. thonningii stem-bark ethanolic extract (FTE) on renal and cardiovascular functions as complications of diabetes. Oral glucose tolerance tests were conducted in separate groups of non-diabetic and STZ-treated diabetic rats given glucose load (0.86 g x kg(-1), p.o.) after 18-h fast, followed by various FTE doses (60, 120, and 240 mg x kg(-1)). Rats treated with deionized water (3 mL x kg(-1) p.o.), or metformin (500 mg x kg(-1) p.o.) acted as untreated and treated positive controls, respectively. Blood glucose was monitored at 15-min intervals for the first hour, and hourly thereafter for 3 h. Acute effects of FTE on kidney function and mean arterial blood pressure (MAP) were investigated in anaesthetized rats challenged with hypotonic saline after a 3.5-h equilibration for 4 h of 1 h control, 1.5 h treatment, and 1.5 h recovery periods. FTE was added to the infusate during the treatment period. Chronic effects of FTE were studied in individually caged rats treated daily with FTE (120 mg x kg(-1), p.o.) for five weeks. Cytotoxicity of FTE was assessed by dye-reduction colorimetric (MTT) assay on MDBK and LLCPK1 kidney cell lines exposed for 24 h, 48 h, and 72 h to graded concentrations of the extract. Myocardial contractile performance was evaluated on rat isolated atrial muscle strips. FTE, like metformin, decreased blood glucose levels in non-diabetic and STZ-diabetic rats. Both acute and chronic FTE treatments did not affect renal function. In vitro studies demonstrated that FTE increased MDBK cell metabolic activity by an average of 15% (72 h), and LLCPK1 mirrored the controls. Acute intravenous infusion of FTE reduced the MAP from 119 +/- 1 mmHg to 98 +/- 4 mmHg. The MAP also was reduced throughout the five-week experimental study period. FTE also produced concentration-dependent, negative inotropic and chronotropic effects on rat isolated, electrically driven left-, and spontaneously beating right-, atrial muscle preparations. Our experimental findings suggest that FTE possesses reno- and cardio-protective effects in diabetes mellitus.