Anti-diabetic effects of Panax notoginseng saponins and its major anti-hyperglycemic components

Ethnopharmacological relevance

Panax notoginseng (Burk) F.H. Chen (Araliaceae) is a well-known and commonly used traditional Chinese herb for treatment of various diseases, such as hemostasis, edema and odynolysis.

Aim of study

Our aim was to investigate the mechanisms of anti-hyperglycemic and anti-obese effects of Panax notoginseng saponins (PNS) in KK-Ay mice, and explore the components in PNS for such effects.

Materials and methods

KK-Ay mice received daily intraperitoneal injections of PNS 200 mg/kg or vehicle for 30 days while ginsenoside Re 14 mg/kg, Rd 15 mg/kg, Rg1 40 mg/kg, Rb1 60 mg/kg and notoginsenoside R1 6 mg/kg for 12 days. Fasting blood glucose levels (FBGL), glucose tolerance (GT), serum insulin, leptin levels, body weight changes, food intake, adipose tissues and blood fat levels were measured at different time points.

Results

The PNS group had significantly lower FBGL, improved GT and smaller body weight incremental percentage after the 30-day treatment. Additionally, Rb1 exhibited significant reduction of FBGL on day 12, and Re also exhibited a decreasing trend after the 12-day treatment.

Conclusions

PNS possess anti-hyperglycemic and anti-obese activities by improving insulin- and leptin sensitivity, and Rb1 is responsible for the anti-hyperglycemic effect among the five saponins in KK-Ay mice.     

Pharmacological characterization of different fractions of Calotropis procera (Asclepiadaceae) in streptozotocin induced experimental model of diabetic neuropathy

Ethnopharmacological relevance

Calotropis procera (Ait.) R.Br. is one of an ancient traditional shrub, which has been used for the treatment of diabetes, pain and inflammation for thousands of years in India. The root extract of Calotropis procera has been widely used by the tribal?s of district Udaipur, Rajasthan (India) for treatment of diabetes mellitus and its associated complications like diabetic neuropathy. The present study was performed to explore the protective effect of root, stem and leaf extracts of Calotropis procera in diabetes and diabetic neuropathy against tactile allodynia, mechanical hyperalgesia and thermal hyperalgesia in streptozotocin induced diabetic rats.

Materials and methods

Diabetes and peripheral neuropathy were induced in Wistar rats by injection of streptozotocin (45 mg/kg/intraperitoneally). The roots, stem and leaves of Calotropis procera were sequentially extracted with petroleum ether, chloroform, ethyl acetate and methanol. All the extracts were assessed by oral administration at 100 and 250 mg/kg in streptozotocin diabetic rats. The following compounds were used as positive controls: insulin NPH (1 IU/kg/day), metformin (500 mg/kg/day), glibenclamide (2.5 mg/kg/day) and a combination of acarbose (20 mg/kg/day) with methylcobalamine (500 µg/kg/day). In contrast, the streptozotocin induced untreated diabetic rats termed as negative control. Thermal hyperalgesia, mechanical hyperalgesia and tactile allodynia were evaluated in all groups of streptozotocin diabetic rats to assess the extent of neuropathy by Eddy?s hot plate, tail immersion, Randall–Selitto and Von Frey hair tests. The basal nociceptive thresholds were assessed in week 4 of post streptozotocin injection. All groups received their treatment on a regular basis from 28 to 42 days following a confirmation of diabetic neuropathy. The nociceptive thresholds were assessed in all groups in week 5 and 6. The histopathology of pancreas and biochemical estimations of plasma insulin and glycosylated haemoglobin (HbA₁C%) levels were also performed in week 6 of post streptozotocin injection.

Results

The negative control rats developed diabetes and diabetic neuropathy after 6 week of streptozotocin administration distinguished by significant (p<0.01) hyperalgesia and tactile allodynia with enhanced HbA₁C% level compared to normoglycemic rats. Chronic administration of root methanol, stem methanol and leaf ethyl-acetate extracts of Calotropis procera for 2 weeks at 100 and 250 mg/kg doses significantly (p<0.01) attenuated the diabetes induced mechanical hyperalgesia, thermal hyperalgesia, tactile allodynia and HbA₁C% level in streptozotocin diabetic rats as compared to negative control rats. Further, the root methanol extract of Calotropis procera in 100 mg/kg dose showed the regeneration capability of β cells in the histology of pancreas with significant (p<0.01) improvement in plasma insulin level in streptozotocin diabetic rats compared to negative control rats.

Conclusion

Root methanol extract of Calotropis procera (100 mg/kg) has shown ameliorative effect in diabetic neuropathy which may be attributed by its multiple actions including potent hypoglycemic and antioxidant.     

Subchronic toxicity study of Coptidis Rhizoma in rats

Ethnopharmacological relevance

Coptidis Rhizoma (CR) is a medical herb from the family Ranunculacease that has been used to treat gastroenteritis, dysentery, diabetes mellitus, and severe skin diseases.

Aim of the study

To evaluate the no-observed-adverse-effect level (NOAEL) and the toxicity of CR, following repeat oral administration to rats for 13 weeks.

Materials and methods

CR was administered by oral gavage to groups of rats (n=10/group, each sex) at dose levels of 0 (control), 25, 74, 222, 667 or 2000 mg/kg/day 5 times per week for 13 weeks. Mortality, clinical signs, body weights, food consumption, hematology, serum chemistry, urinalysis, vaginal cytology and sperm morphology, organ weights, gross and histopathological findings were compared between control and CR groups.

Results

Urinalysis showed a significant increase in N-acety1-β-glucosaminidase in males in the 2000 mg/kg/day group (P<0.01). However, no mortality or remarkable clinical signs were observed during this 13-week study. No adverse effects on body weight, food consumption, hematology, serum chemistry, organ weights, gross lesion, histopathology, vaginal cytology, sperm motility, or deformity were observed in the males or female rats treated with CR.

Conclusions

On the basis of these results, the NOAEL of CR is determined to be 667 mg/kg/day for males and 2000 mg/kg/day for females.     

Potent relaxant effect of a Celastrus paniculatus extract in the rat and human ileum

Ethnopharmacological importance

Celastrus paniculatus Willd. (Celastraceae) is an Ayurvedic remedy used for the treatment of a number of diseases, including bowel spasms.

Aim of the study

To investigate the mode of the relaxing action of a methanolic extract prepared from the seeds of Celastrus paniculatus (CPE, 0.0001–10 μg/mL) in the rat ileum and to try to confirm on human tissues the intestinal pharmacological activity of the extract.

Materials and methods

The relaxant effect of CPE was studied in vitro by evaluating its effect on the spontaneous contractions of the isolated ileum.

Results

CPE exerted a tetrodotoxin- and ω-conotoxin-resistant inhibitory effect on rat ileum motility (IC₅₀: 0.24 ± 0.02 μg/mL; E_max: 99.0 ± 0.60%). The inhibitory effect was reduced by nifedipine but not by cyclopiazonic acid. Experiments with specific antagonists enabled us to exclude the involvement of the main endogenous spasmogenic (i.e. acetylcholine and tachykinins) and relaxing (noradrenaline, nitric oxide, ATP) compounds. CPE also relaxed the isolated human ileum (IC₅₀: 0.26 ± 0.02 μg/mL; E_max: 99.1 ± 0.46%).

Conclusion

It is concluded that (i) CPE exerted a powerful myogenic and L-type Ca²⁺-dependent relaxing effect in the isolated rat ileum and that (ii) the human ileum is sensitive to the inhibitory effect of CPE. If confirmed in vivo, our data could explain the traditional use of this herb in the treatment of intestinal spasms.     

Antihyperglycaemic activity of aqueous leaf extract of Combretum micranthum (Combretaceae) in normal and alloxan-induced diabetic rats

Aim of the study

To investigate antidiabetic effect of the leaves of Combretum micranthum G. Don, a medicinal plant used for treating diabetes in Northwestern Nigeria.

Materials and methods

Three doses (100 mg/kg, 200 mg/kg and 400 mg/kg) of the aqueous leaf extract of Combretum micranthum were administered to normal glucose loaded, subdiabetic and diabetic rats.

Results

Of the doses tested, 100 mg/kg of the extract was the most effective. It produces a significant hypoglycaemic and antidiabetic activity comparable to the effect of standard drug (0.6 mg/kg glibenclemide).

Conclusion

This study demonstrated the potential antidiabetic property of aqueous leaf extract of Combretum micranthum thus justifying its traditional usage.     

The anti-arthritic effects of Aconitum vilmorinianum, a folk herbal medicine in Southwestern China

Ethnopharmacological relevance

Aconiti Radix (AC) and Aconiti Kusnezoffii Radix (AK) are two traditional Chinese medicines commonly used to treat joint pain and arthritis. In Southwestern China, Huangcaowu (AV), the root of Aconitum vilmorinianum Kom., has long been used as a local substitute for these herbs for analgesia and anti-inflammation. However, its anti-arthritic effects have not been investigated.

Aim of study

To investigate the anti-arthritic effects of Huangcaowu (AV).

Materials and methods

Mono-arthritis in SD rats was induced by unilateral intra-articular injection of Freund's complete adjuvant. Physiological saline was injected in the contralateral knee. Seventy five percent ethanol extracts of AV (10 mg/kg/day and 100 mg/kg/day), AC (100 mg/kg/day) and AK (100 mg/kg/day) were administered to rats by oral gavage for 14 consecutive days (Day -6 to Day 7) while arthritis was induced at the seventh day (Day 0). The anti-arthritic effects of the herbs were assessed by measuring allodynia, swelling, hyperaemia and the vascular permeability of the knee joints.

Results

AV (10 mg/kg/day and 100 mg/kg/day), AC (100 mg/kg/day) and AK (100 mg/kg/day) suppressed joint allodynia. AV (10 mg/kg/day and 100 mg/kg/day) and AK (100 mg/kg/day) significantly reduced join swelling and hyperaemia while AC (100 mg/kg/day) did not. AV (100 mg/kg/day) attenuated vascular permeability while AC (100 mg/kg/day) and AK (100 mg/kg/day) showed no improvement.

Conclusions

Huangcaowu (AV) significantly improved allodynia, swelling, hyperaemia and vascular permeability in arthritic knee joints. It showed the highest anti-arthritic effects among the three tested Aconitum herbs.     

Further evaluation of antihyperglycaemic activity of Hunteria umbellata (K. Schum) Hallier f. seed extract in experimental diabetes

Ethnopharmacological relevance

In African traditional medicine, water decoction made from the dry seeds of Hunteria umbellata (K. Schum) Hallier f. is highly valued in the management of diabetes mellitus.

Aim

In the present study, the antihyperglycaemic activity of the seed aqueous extract of Hunteria umbellate (K. Schum) Hallier f. (HU) was investigated in alloxan-induced, high fructose- and dexamethasone-induced hyperglycaemic rats.

Materials and methods

Alloxan-induced, dexamethasone-induced and high fructose-induced hyperglycaemic rats were treated with single, daily oral administration of 1 mg/kg of glibenclamide, 50 mg/kg, 100 mg/kg and 200 mg/kg of HU in Groups III, IV, V and VI, for 14 days, 21 days and 8 weeks, respectively. The effects of these drugs on FBG, free plasma insulin levels, HbA_1c, serum TG and TC, and insulin resistance indices were investigated.

Results

Data generated in the current study showed that glibenclamide and graded oral doses of HU caused significant dose related (p < 0.05, <0.01 and <0.001) reductions in FBG when compared to the values obtained for the model control (Group II) rats. Similarly, daily oral administration of 66.7 g/kg fructose to rats for 8 weeks was associated with significant (p < 0.001) hyperglycaemia, elevations in plasma HbA_1c, free insulin, fasting insulin resistance indices, serum TG, and cholesterol. However, concomitant oral treatments with 1 mg/kg of glibenclamide, 50 mg/kg, 100 mg/kg, and 200 mg/kg of HU extract significantly and dose dependently (p < 0.05, <0.01 and <0.001) attenuated development of hyperglycaemia, decreased levels of plasma HbA_1c, free insulin, and serum triglyceride and cholesterol, in the Groups III, IV, V and VI rats, respectively, when compared to fructose-induced hyperglycaemic (Group II) rats. Similar effect was also recorded in the dexamethasone-induced hyperglycaemic rats.

Conclusion

Results of this study suggest that the hypoglycaemic and antihyperlipidaemic effects of HU are mediated via enhanced peripheral glucose uptake and improvements in hyperinsulinaemia.     

Effects of ethanolic dried leaf extract of Lecaniodiscus cupanioides on antioxidant enzymes and biochemical parameters in rats

Ethnopharmacological relevance

Lecaniodiscus cupanioides is widely used in West African folk medicine for the treatment of inflammatory conditions, fevers and bacterial infections.

Aim of the study

To evaluate the potential toxic effects of the ethanolic dried leaf extract of Lecaniodiscus cupanioides (LC) on antioxidant enzymes in selected organs and biochemical parameters.

Materials and Methods

Crude ethanolic extract of Lecaniodiscus cupanioides dried leaves was prepared. A 90-day sub-chronic toxicity study was conducted using albino rats. Reconstituted Lecaniodiscus cupanioides was administered at a dosage of 400, 800 and 1600 mg/kg (high dose) with a control group receiving 10 ml/kg orally. Histopathological studies of major organs and blood chemistry analysis were performed on blood obtained via cardiac puncture after euthanization. Selected organs (liver, kidney and brain) were harvested for antioxidant and histopathological assessments.

Results

The extract produced significant (p<0.05) increases in the weights of liver, kidney and brain at 800 mg/kg and 1600 mg/kg compared to the control. Biochemical analysis showed significant increase in Alanine transferase (ALT) at 800 mg/kg and 1600 mg/kg. Assay for antioxidant enzymes showed a reversible decrease in the activity of Catalase (CAT), Superoxide dismutase (SOD) and Glutathione (GSH) with an increase in Malondialdehyde (MDA) at 800 mg/kg and 1600 mg/kg Lecaniodiscus cupanioides. Histopathological study showed reversible congestion in the brain, liver, and kidney at 800 mg/kg and 1600 mg/kg.

Conclusion

Findings in this study reveal that the ethanolic dried leaf extract of Lecaniodiscus cupanioides has the potential for inhibiting in vivo antioxidant enzymes activity and causing hepatotoxicity after prolonged exposure.     

Extract of the Chinese herbal formula Huo Luo Xiao LingDan inhibited adjuvant arthritis in rats

Ethnopharmacological relevance

The herbal formula Huo Luo Xiao Ling Dan (HLXL) and its modifications have been used in traditional Chinese medicine for about one hundred years to alleviate pain and inflammation.

Aim

To investigate the effects of HLXL on complete Freund's adjuvant (CFA)-induced multiple-joint arthritis in rats.

Materials and methods

Male Lewis rats, 190–210 g, were immunized subcutaneously at the base of the tail with 200 μl of heat-killed Mycobacterium tuberculosis in mineral oil (5 mg/ml). HLXL (2.30 and 4.60 g/kg) or vehicle control (n = 8 per group) was administered orally (i.g.) once a day between days 16 and 25 post-CFA injection. The rats were observed for signs of arthritis with arthritic changes (erythema, edema, induration) being scored on a scale of 0–4 of increasing severity using a standard scoring system. The maximum arthritis score per rat was 16. A plethysmometer was used to measure edema volume in each paw. Adverse effects of HLXL were monitored by closely observing the animals for unusual behavioral changes. Levels of tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) in local tissue were measured by enzyme-linked immunosorbent assay on day 25 post-CFA.

Results

HLXL significantly decreased arthritis scores between days 23–25 in the 2.30 g/kg group and 21–25 in the 4.60 g/kg group (p < 0.05). It reduced paw edema on days 22 and 24 in the 2.30 g/kg group and on days 20, 22 and 24 in the 4.60 g/kg group compared to control (p < 0.05). Local tissue TNF-α and IL-1β levels on day 25 post-CFA injection were significantly (p < 0.05) lower in rats treated with HLXL than in control rats. No observable adverse effects were found.

Conclusion

The data suggest that HLXL produces significant anti-arthritic effects that may be mediated by suppressing pro-inflammatory cytokines, and it appears to be safe.     

Antihyperglycemic and hypolipidemic activity of aqueous extract of Cassia auriculata L. leaves in experimental diabetes

Ethnopharmacological relevance

Cassia auriculata L. (Caesalpiniaceae) is widely used from ancient period to treat diabetes mellitus. The leaves of Cassia auriculata are having potential in the development of drug for diabetes due to its antihyperglycemic and lipid-lowering activity.

Aim of the study

The present study was to evaluate antihyperglycemic and hypolipidemic activity of aqueous extract of Cassia auriculata leaves (CLEt) in streptozotocin (STZ)-induced mild diabetic (MD) and severe diabetic (SD) rats.

Materials and methods

Male Albino rats were rendered diabetic by STZ (45 mg/kg, intraperitoneally). CLEt was orally administered to MD and SD rats at 100, 200 and 400 mg/kg doses for 1 day to determine antihyperglycemic activity. The 400 mg/kg dose was administered daily for 3 weeks to assess glycemic control and hypolipidemic effect.

Results

CLEt showed dose dependant fall in fasting blood glucose (FBG). After 5 h of extract administration at 400 mg/kg dose, FBG was reduced by 13.9% and 17.4% in MD and SD rats respectively. After 3 weeks treatment, CLEt produced significant reduction in FBG and glycosylated haemoglobin (GHb) in both MD and SD rats. Serum lipid levels were reversed towards normal in extract fed MD and SD rats.

Conclusions

The results demonstrate that CLEt possesses potent antihyperglycemic and hypolipidemic activity in both MD and SD rats.     

Antinociceptive effect of Lecythis pisonis Camb. (Lecythidaceae) in models of acute pain in mice

Ethnopharmacological relevance

Lecythis pisonis Camb., also known in Brazil as sapucaia, is used in folk medicine against pruritus, muscle pain and gastric ulcer.

Aim of the study

To investigate the antinociceptive effect of ethanol extract from Lecythis pisonis leaves (LPEE), fractions (hexane-LPHF, ether-LPEF and ethyl acetate-LPEAF) and mixture of triterpenes [ursolic and oleanolic acids (MT)] in mice.

Materials and methods

LPEE and LPEF were evaluated on the acetic acid induced writhings and formalin, capsaicin and glutamate tests. In addition, MT was investigated on the writhings induced by acetic acid, capsaicin and glutamate tests. In the study of some possible mechanisms involved on the antinociceptive effect of LPEF, it was investigated the participation of opioid system, K⁺_ATP channels and l-arginine-nitric oxide pathway.

Results

LPEE (12.5 and 25 mg/kg, p.o.), LPEF and MT (6.25, 12.5 and 25 mg/kg, p.o.) reduced the writhings in comparison to saline. LPEE (100 mg/kg, p.o.) and LPEF (50 mg/kg, p.o.) were effective in inhibiting both phases of formalin test. In capsaicin test, LPEE (100 and 200 mg/kg, p.o.), LPEF (12.5–50 mg/kg, p.o) and MT (6.25–25 mg/kg, p.o.) showed a significant antinociceptive effect compared to the control. LPEE (25 and 50 mg/kg, p.o.), LPEF (50 and 100 mg/kg, p.o.) and MT (12.5 and 25 mg/kg, p.o.) reduced the glutamate-evoked nociceptive response. Treatment with naloxone, l-arginine and glibenclamide reversed the effect of LPEF in glutamate test.

Conclusions

These results indicate the antinociceptive effect of Lecythis pisonis leaves and suggest that this effect may be related to opioid pathway, K⁺_ATP channels, and l-arginine-nitric oxide modulation. Furthermore, these data support the ethnomedical use of this plant.     

Evaluation of reproductive and developmental toxicities of Pu-erh black tea (Camellia sinensis var. assamica) extract in Sprague Dawley rats

Ethnopharmacological relevance

Pu-erh black tea, which is obtained by first parching crude green tea leaves and followed by secondary fermentation with microorganisms, has been believed to be beneficial beverages for health in PR China. But its potential toxicity when administered at a high dose as concentrated extract has not been completely investigated.

Aim of the study

The present study was aimed at evaluating potential reproductive and developmental toxicities of Pu-erh black tea extract (BTE) in Sprague Dawley rats.

Materials and methods

Growing rats were given BTE by gavage at levels of 0, 200, 700 and 2500 mg/kg/day as the F₀ generation in reproductive toxicity study. Additionally, BTE was administered to mate female rats from gestation day 0.5 through 19.5 at the doses of 0, 200, 700 and 2500 mg/kg/day to evaluate the developmental toxicity.

Results

In the reproductive toxicity study, only 2500 mg/kg/day BTE reduced the body weight gain and altered the relative organ weights including testes, prostata and ovary both for F₀ parents and F₁ offspring compared to the controls. High dose of BTE (2500 mg/kg/day) administration caused developmental disturbances in embryo-to-foetus period including resorbed embryos, decreased embryo size and skeletal anomalies.

Conclusion

In conclusion, the no-observed-adverse-effect level of BTE is 700 mg/kg/day both for reproductive toxicity and developmental toxicities.     

Effect of antler extract on corticosteroid-induced avascular necrosis of the femoral head in rats

Ethnopharmacological relevance

Deer antler, traditionally used as a tonic and valuable drug in oriental medicine, has been considered to possess bone-strengthening activity and effectively used in bone diseases therapy.

Aim of the study

The present study was designed to investigate therapeutic effect of antler extract on avascular necrosis of the femoral head (ANFH) induced by corticosteroids in rats.

Materials and methods

Rats were intragluteally injected with dexamethasone at 50 mg/kg twice per week for 6 weeks to induce ANFH. Then the rats were treated with antler extract by oral gavage at 200 mg/kg, 400 mg/kg and 800 mg/kg once per day for 60 days. The concentration of hydroxyproline and hexosamine in serum was measured and the ultrastructure of femoral head was examined. In vitro, effect of the drug-containing serum of antler extract on proliferation and differentiation of primary osteoblasts were investigated by MIT assay, ALP activity assay and cell cycle analysis.

Results

After treatment with antler extract, the degree of necrosis induced by dexamethasone was significantly reduced, hydroxyproline was significantly decreased, and hexosamine and the ratio of hexosamine/hydroxyproline were significantly increased. The drug-containing serum of antler extract promotes osteoblastic proliferation through regulation of cell cycle progression.

Conclusions

The results suggest that antler extract has a positive curative effect on ANFH by promoting osteoblastic proliferation.     

Shikonin ameliorates cerulein-induced acute pancreatitis in mice

Ethnopharmacological relevance

Shikonin, a highly liposoluble naphthoquinone pigment isolated from the traditional medical herbs Lithospermum erythrorhizon (LE), was considered to exhibit an anti-inflammatory property. While the potential of shikonin to ameliorate acute pancreatitis (AP) is unknown. Our aim was to investigate the effects of shikonin in a murine model of cerulein-induced pancreatitis.

Materials and methods

AP was induced in mice by six intraperitoneal injection of cerulein (50 μg/kg) at hourly intervals. Vehicle or shikonin (50 mg/kg) was pretreated 2 h before the first cerulein injection. After 6 h, 9 h and 12 h of the first cerulein injection, the severity of acute pancreatitis was assessed by biochemistry, myeloperoxidase activity, histological grading, proinflammatory cytokines levels and nuclear factor kappa B (NF-κB) activity.

Results

Shikonin administration significantly reduced serum amylase and lipase activities, pancreatic histological scores, TNF-α, IL-1β, IL-6 levels, MPO activity and NF-κB activity.

Conclusion

Taken together, these results suggest that shikonin might protect against experimental pancreatitis by reducing release of inflammatory cytokines via inhibition of NF-κB activity. The therapeutic role of shikonin in AP needs further investigation.     

Emblica officinalis and hepatocarcinogenesis: A chemopreventive study in Wistar rats

Introduction

Emblica officinalis L. commonly known as gooseberry, Phyllanthus emblica, Emblica, Indian gooseberry, amla is used in Indian system of medicine for the treatment of liver ailments.

Aim and Objectives

In the present study, we report that it ameliorates the carcinogenic response as it reverses the histopathological changes and reduces the number of γ-GT-positive foci induced by Solt Farber protocol in the liver of Wistar rats.

Materials and Methods

Tumors were induced by initiation with diethylnitrosoamine (DEN) (200 mg/kg body wt., i.p.) followed by promotion with 2-acetylaminoflourine (2-AAF) (0.02%, w/w in diet) for continuous 6 weeks and the animals were subjected to partial hepatectomy on day 21 of initiation.

Results

Pretreatment with defatted methanolic fruit extract (100 and 200 mg/kg b.w.) of Emblica officinalis showed significant partial recovery of pathological manifestations as compared to DEN and 2-AAF-treated group animals (p < 0.001) and suppressed the tumor forming potential of 2-AAF (p < 0.05) at both the doses.

Conclusion

Emblica officinalis has the potential to suppress carcinogen-induced response in rat liver.     

Antihypertensive activities of the aqueous extract of Kalanchoe pinnata (Crassulaceae) in high salt-loaded rats

Ethnopharmacological relevance

The leaves of Kalanchoe pinnata (Crassulaceae) are used in Cameroon folk medicine to manage many diseases such as cardiovascular dysfunctions. In this work, we aimed to evaluate the activities of aqueous leaf extract of Kalanchoe pinnata on the blood pressure of normotensive rat (NTR) and salt hypertensive rats (SHR), as well as its antioxidant properties.

Materials and methods

Hypertension was induced in rats by oral administration of 18% NaCl for 4 weeks. For the preventive study, three groups of rats received 18% NaCl solution and the plant extract at 25 mg/kg/day, 50 mg/kg/day or 100 mg/kg/day by gavage. Two positive control groups received 18% NaCl solution and either spironolactone (0.71 mg/kg/day) or eupressyl (0.86 mg/kg/day) by gavage for 4 weeks. At the end of this experimental period, systolic arterial pressure (SAP), diastolic arterial pressure (DAP) and heart rate (HR) were measured by the invasive method. Some oxidative stress biomarkers (reduced glutathione (GSH), superoxide dismutase (SOD), nitric monoxide (NO) were evaluated in heart, aorta, liver and kidney. NO level was indirectly evaluated by measuring nitrite concentration.

Results

Kalanchoe pinnata extract prevented significantly the increase of systolic and diastolic arterial pressures in high salt-loaded rats (SHR). In SHR, concomitant administration of Kalanchoe pinnata at 25, 50 and 100 mg/kg/day significantly prevented the increase in blood pressure by 32%, 24% and 47% (for SAP); 35%, 33% and 56% (for DAP), respectively. No significant change was recorded in heart rate of those rats. The plant extract improved antioxidant status in various organs, but more potently in aorta. Thus, antioxidant and modulatory effects of Kalanchoe pinnata at the vasculature might be of preponderant contribution to its overall antihypertensive activity.

Conclusion

The work demonstrated that the concomitant administration of high-salt and the aqueous extract of Kalanchoe pinnata elicits prevention of salt-induced hypertension in rat. This antihypertensive activity is associated with an improvement of antioxidant status. Overall, results justify and support the use of Kalanchoe pinnata as antihypertensive medicine.     

Acute and sub-chronic toxicity profile of methanol leaf extract of Gouania longipetala in rats

Ethnopharmacological relevance

Gouania longipetala leaves are commonly used in folkloric medicine in Africa and other parts of the world for treatment of edema, febrifuges, veneral diseases, lumbago, heart diseases, diabetes mellitus malaria, etc. This study therefore evaluated safety profile of the methanol leaf extract of the plant using acute and sub-chronic studies in rat model.

Materials and methods

Acute toxicity test of the plant lasted for 48 h with oral administration of graded doses (100–4000 mg/kg) of Gouania longipetala extract (GLE) in rats. The rats were observed for signs of toxicity and death. The sub-chronic toxicity was evaluated by administration of different doses (2.5, 5 and 10 mg/kg) of GLE daily in feed for 90 days. On days, 30, 60 and 90, blood samples collected from the retro-orbital plexus of the eye of the rats were used for evaluation of serum biochemistry, hematology, lipid peroxidation and in vivo antioxidant activities. Histopathological evaluations of the kidney, liver, lungs and heart were also done.

Results

The acute toxicity test revealed no observable signs of toxicity or morbidity. Sub-chronic study showed that GLE significantly (p<0.05) increased relative liver weight on day 90 at 10 mg/kg. There were no significant variations in the hematological parameters of both GLE treated and untreated rats. The extract significantly (p<0.05) reduced total cholesterol, triglycerides, very low density lipoproteins and increased high density lipoproteins which was more prominent on day 90 at the dose of 10 mg/kg. The extract significantly (p<0.05) increased liver enzyme markers at the doses used. GLE also significantly (p<0.05) increased serum urea at the dose of 10 mg/kg on day 90. The extract caused dose-dependent and significant (p<0.05) increase in superoxide dismutase and decrease in malondiadehyde. Histopathological studies revealed degenerative changes in the kidney and liver.

Conclusion

The results of the study suggest that Gouania longipetala is well tolerated in short term therapies, but may have long term toxic effects on the kidney and liver.     

Anti-inflammatory intestinal activity of Abarema cochliacarpos (Gomes) Barneby & Grimes in TNBS colitis model

Aim of the study

To assess the anti-inflammatory effect of butanolic fraction of methanolic extract from bark of Abarema cochliacarpos in acute ulcerative colitis model induced by intracolonic administration of trinitrobenzene sulfonic acid (TNBS) in Wistar rats.

Materials and methods

Abarema cochliacarpos (100 and 150 mg/kg/day) was administered by gavage 48, 24 and 1 h prior to the induction of colitis with 10 mg/kg of TNBS and, 24 h later.

Results

Phytochemical studies by mass spectrometry (MS) and nuclear magnetic resonance spectroscopy (NMR) revealed that catechins were a major component into condensate class of tannins. Treatment with Abarema cochliacarpos decreased significantly macroscopic damage as compared with TNBS (p < 0.05). Histological analysis showed that both doses of the extract improved the microscopic structure and preserved some areas of the colonic mucosa structure. In addition, myeloperoxidase activity (MPO), as a marker of neutrophil infiltration, was decreased in a dose-dependent way (p < 0.01 and p < 0.001 respectively), TNF-α level was also diminished with the highest dose of the extract (p < 0.001) and, IL-10 level obtained no significant results. In order to elucidate some of the mechanisms, expression of inducible inflammatory enzymes, such as cyclooxygenase (COX)-2 and nitric oxide synthase (iNOS), were studied showing a significant reduction. Finally, the involvement of c-Jun N-terminal kinase (JNK) signalling demonstrated a reduction in the JNK activation with the highest dose (p < 0.05 vs TNBS).

Conclusions

We have shown for the first time that the extracts obtained from Abarema cochliacarpos bark possess active substances, which exert marked protective effects in acute experimental colitis, confirming and justifying, at least in part, the popular use of this plant to treat gastrointestinal diseases.