The effect of Salvia divinorum and Mitragyna speciosa extracts,fraction and major constituents on place aversion and place preference in rats

Ethnopharmacological relevance

Consumer use of botanicals has increased despite, in many instances, the paucity of research demonstrating efficacy or identifying liabilities. This research employed the place preference/aversion paradigm to characterize the psychoactive properties of Salvia divinorum extract (10, 30, 100 mg/kg), salvinorin A (0.1, 0.3, 1.0 mg/kg), Mitragyna speciosa MeOH extract (50, 100, 300 mg/kg), Mitragyna speciosa alkaloid-enriched fraction (12.5, 25, 75 mg/kg) and mitragynine (5, 10, 30 mg/kg) in rats.

Material and methods

Following apparatus habituation and baseline preference scores, male Sprague-Dawley rats were given eight counter-balanced drug versus vehicle conditioning trials followed by a preference test conducted under drug-free states. S(+)-amphetamine (1 mg/kg) served as the positive control (in Exp. 2) and haloperidol (0.8, 1.0 mg/kg) served as the negative control in both studies.

Results

Rats displayed place aversion to both Salvia divinorum and salvinorin A that exceeded that of haloperidol. Rats showed place preference to mitragynine that was similar to that of S(+)-amphetamine. This CPP effect was much less pronounced with the Mitragyna speciosa extract and its fraction.

Conclusions

These findings suggest that both botanicals possess liabilities, albeit somewhat different, that warrant caution in their use.     

Qualea parviflora Mart.: An integrative study to validate the gastroprotective,antidiarrheal, antihemorragic and mutagenic action

Ethnopharmacological relevance

Qualea parviflora Mart. is a medicinal species commonly found in the Brazilian Cerrado biome.

Aim of the study

Based on ethnopharmacological data, methanolic extract from Qualea parviflora (QP) bark was evaluated for its antiulcer, analgesic, anti-hemorrhagic, mutagenic and anti-Helicobacter pylori activities.

Material and methods

The gastroprotective action of the extract was evaluated in rodent experimental models (HCl/ethanol, ethanol or NSAID). We also evaluated mutagenic effect (Ames assay), anti-Helicobacter pylori, anti-hemorrhagic action, analgesic and inflammatory effects (hot-plate test and carrageenin-induced hind paw edema) of methanolic extract from Qualea parviflora.

Results

QP (500 mg/kg, p.o.) was able to protect gastric mucosa against HCl/ethanol solution (77%), absolute ethanol (97%), and also against injurious effect of NSAID (36%). When QP was challenged with sulfhydryl depletor compound, the gastroprotective action of extract was abolished. QP treatment was able to maintain the GSH level and show a concentration-dependent inhibition effect on the lipid peroxidation. QP present anti-Helicobacter pylori effect (MIC = 75 μg/mL), anti-hemorrhagic and antidiarrheal action but not present analgesic or anti-inflammatory effect.

Conclusion

methanolic extract from Qualea parviflora had gastroprotective effect related to the increase of gastric mucosa defensive factors such PGE₂ levels and maintain the basal gastric glutathione levels. The methanolic extract also showed anti-Helicobacter pylori activity, anti-hemorrhagic effect and antioxidant action, but absence of analgesic, mutagenic and toxic effects, a profile that adds safety to its use.     

Renoprotective effects of the crude extract and solvent fractions of the leaves of Euclea divinorum Hierns against gentamicin-induced nephrotoxicity in rats

Ethnopharmacological relevance

Euclea divinorum Hierns (Ebenaceae) is used in Ethiopian folklore medicine to treat scabies, inflammation of the skin, eczema, abdominal pain, gonorrhea, and kidney problems. However, the claim has not been scientifically validated.

Aim of the study

To assess the renoprotective effects of the crude extract and solvent fractions of E. divinorum leaves against gentamicin-induced nephrotoxicity in rats.

Materials and method

Rats of either sex were divided into seven experimental groups, each comprising six animals. Group I served as control and given vehicle (Tween 80, 2%, v/v in water) and Group II were treated with gentamicin intraperitoneally (100 mg/kg/day) for eight days. Group III–V received crude extract at three different doses 100 mg/kg, 150 mg/kg and 200 mg/kg, respectively. Group VI received 100 mg/kg of the methanolic fraction and Group VII 100 mg/kg of the aqueous fraction. The extract was administered orally two days before and eight days concomitantly with gentamicin. Following treatment, blood and renal tissue were used to assess creatinine, blood urea nitrogen (BUN), malondialdehyde (MDA), antioxidant enzymes and tubular necrosis using recommended procedures. In addition, free radical scavenging activity was determined using in vitro methods.

Results

Gentamicin significantly increased serum creatinine and BUN, MDA and tubular necrosis in rats. It also decreased activity of catalase and superoxide dismutase as well as levels of gluthatione. Pre- and co-treatment with the crude extract and solvent fractions of Euclea divinorum leaves reversed gentamicin-induced alterations as evidenced by a decrease in tubular necrosis, serum and oxidant markers as well as by an increase in antioxidant molecules. Effect was found to decrease with dose when the crude extract was used and maximum protection was conferred by 100 mg/kg of the methanolic fraction in both in vivo and in vitro studies.

Conclusions

Euclea divinorum reversed gentamicin-induced nephrotoxicity, probably via its antioxidant activity. The fact that the methanol fraction conferred maximum protection suggests that semi-polar antioxidant principles might be responsible for the observed effect.     

Subchronic exposure to mitragynine,the principal alkaloid of Mitragyna speciosa, in rats

Ethnopharmacological relevance

Mitragyna speciosa is a popular medicinal plant in Southeast Asia which is commonly used for its morphine-like effects. Although the analgesic properties of Mitragyna speciosa and its ability to ameliorate withdrawal signs after abrupt cessation of opioid abuse are well known, information about the long-term safety of the plant's active compounds is lacking. In this work, we evaluated the effects of sub-chronic exposure to mitragynine, the principal alkaloid of Mitragyna speciosa leaves in rats. Materials and methods: Male and female Sprague-Dawley rats received three doses of mitragynine (1, 10, 100 mg/kg, p.o) for 28 days respectively. Food intake and relative body weight were measured during the experiment. After completion of drug treatment biochemical, hematological, and histological analyses were performed.

Results

No mortality was observed in any of the treatment groups. The groups of rats treated with the lower and intermediate doses showed no toxic effects during the study. However, the relative body weight of the group of female rats treated with the 100 mg/kg dose was decreased significantly. Food intake also tended to decrease in the same group. Only relative liver weight increased after treatment with the high dose of mitragynine (100 mg/ kg) in both the male and female treatment groups of rats. Biochemical and hematological parameters were also altered especially in high dose treatment group which corresponds to the histopathological changes.

Conclusions

The study demonstrated that mitragynine is relatively safe at lower sub-chronic doses (1–10 mg/kg) but exhibited toxicity at a highest dose (sub-chronic 28 days: 100 mg/kg). This was confirmed by liver, kidney, and brain histopathological changes, as well as hematological and biochemical changes.     

Neuroprotective activity of Matricaria recutita Linn against global model of ischemia in rats

Ethnopharmacological relevance

Traditionally, the whole plant is used for various diseases, including neuronal disorders.

Aim of the study

To evaluate the neuroprotective effect of Matricaria recutita L. against global cerebral ischemia/reperfusion (I/R) injury-induced oxidative stress in rats.

Materials and methods

Neuroprotective activity was carried out by global cerebral ischemia on Sprague–Dawley rats by bilateral carotid artery (BCA) occlusion for 30 min followed by 60 min reperfusion. The antioxidant enzymatic and non-enzymatic levels were estimated along with cerebral infarction area and histopathological studies.

Results

The Matricaria recutita L. methanolic extract showed dose-dependent neuroprotective activity by significant decrease in lipid peroxidation (LPO) and increase in the superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and total thiol levels in extract treated groups as compared to ischemia/reperfusion group. Cerebral infarction area was significantly reduced in extract treated groups as compared to ischemia/reperfusion group.

Conclusion

The methanolic extract of Matricaria recutita L. showed potent neuroprotective activity against global cerebral ischemia/reperfusion injury-induced oxidative stress in rats.     

Antiplasmodial activity of root extract and fractions of Croton zambesicus

Aim of the study

Antiplasmodial activity of root extract and fractions of Croton zambesicus were evaluated to ascertain the folkloric claim of its antimalarial activity and elucidate its antiplasmodial mechanism of action.

Material and method

The crude ethanolic root extract (27–81 mg/kg) and gradient fractions ( n- hexane, chloroform, ethyl acetate and methanol; 54 mg/kg) of Croton zambesicus were investigated for antiplasmodial activity against chloroquine - sensitive Plasmodium berghei infections in mice. The antiplasmodial activity during early and established infections as well as the prophylactic activity were investigated. Chloroquine (5 mg/kg) and pyrimethamine (1.2 mg/kg) were used as positive controls. Thin films made from tail blood of each mouse were used to assess the level of parasitaemia of the mice. Oxidant generation potentials of the crude extract and fractions was also evaluated to elucidate their mechanism of action.

Results

The crude root extract (27 – 81 mg/kg) demonstrated significant (P < 0.01–0.001) schizonticidal activity during early and established infections and also had prophylactic activity. The activity was comparable to that of the standard drug used (chloroquine 5 mg/kg, pyrimethamine 1.2 mg/kg). Methanol, ethyl acetate and chloroform fractions had comparative in vivo antiplasmodial activity and oxidant generation potentials.

Conclusion

The antiplasmodial activity of this root extract and fractions which is likely to be through peroxidation confirms the folkloric use of this plant.     

Vasorelaxant effects of extracts of the stem bark of Terminalia superba Engler & Diels (Combretaceae)

Aim of the study

The stem bark of Terminalia superba (Combretaceae) (TS) is used in traditional Cameroonian medicine as antihypertensive remedy. In the present study, we investigated the vasorelaxant properties of different extracts of TS and their underlying mechanisms.

Materials and methods

Activities of aqueous (AQU), methanolic (MET), methylene chloride (MC), and methylene chloride–methanol (MCM) extracts of TS were evaluated on isolated rat aortic rings precontracted with phenylephrine (PE) or high KCl.

Results

All extracts induced a vasodilating effect both on KCl- and PE-induced contractions. The effects of MC and MCM extracts were greater than those of AQU or MET extracts (P < 0.05). MC had an endothelium-independent effect and reduced Ca⁺⁺-induced contraction following PE or KCl challenge (P < 0.05). After incubation with verapamil, MC induced a relaxation in rings precontracted by PE (P < 0.001). By contrast, the effect of MCM was endothelium-dependent and decreased by the nitric oxide synthase inhibitor N_W-nitro-l-arginine methyl ester (P < 0.05).

Conclusions

These data demonstrate that the MC extract exhibits vasorelaxant effects that are partly due to inhibition of extracellular Ca⁺⁺ influx and/or inhibition of intracellular Ca⁺⁺ release in vascular smooth muscle cells. By contrast, the effect of the MCM extract was found to be endothelium- and nitric oxide dependent.     

The antinociceptive activity of Polygonatumverticillatum rhizomes in pain models

Aim of the study

The current study was designed to establish the pharmacological rationale for the traditional use of the rhizomes of Polygonatum verticillatum in the treatment of painful conditions and as a plant diuretic.

Materials and methods

The crude methanolic extract of the rhizomes of Polygonatumverticillatum (PR) was tested in various established pain models in rodents at 50, 100 and 200 mg/kg i.p. while the diuretic activity was assessed at 300 and 600 mg/kg p.o. in rats.

Results

PR demonstrated significant reduction (14–72%) in the number of writhes induced by acetic acid in a dose-dependent manner. When nociceptive threshold was measured in the formalin test, PR strongly attenuated the formalin-induced flinching behaviour in both phases (6–30% in first phase while 12–72% in second phase). Central involvement in the analgesic profile of PR was confirmed by the hot plate test, in which PR elicited a significant (P < 0.01) analgesic activity by increasing latency time. However, an opioid receptor antagonist, naloxone (2 mg/kg s.c.) strongly antagonized the antinociceptive activity of PR. As a plant diuretic, PR showed mild but statistically insignificant diuretic activity at 300 mg/kg. The crude extract and solvent fractions of the plant contained reasonable quantity of total saponin and alkaloid contents.

Conclusions

The mechanisms underlying the analgesic action of PR shows that the opioid dependant central mediation has synergistic effect by enforcing the peripheral analgesic effects. Interestingly, our findings not only substantiated the folk use of the plant as an analgesic but also reported for the first time in the whole genus.     

Antiinflammatory and antinociceptive activities of Blechnum occidentale L. extract

Aim of study

Blechnum occidentale L. is a terrestrial fern that ranges from the United States to South America, and is employed in Brazilian folk medicine. In the present study we investigated the antinociceptive and antiinflammatory activities of the methanolic extract of Blechnum occidentale L. (MEB) in animal models of pain and inflammation to support its medicinal use in treatment of inflammatory and pulmonary diseases, urinary infections and liver diseases.

Materials and methods

The antinociceptive activity of MEB was evaluated using the writhing, formalin, and tail flick tests. The antiinflammatory activity of MEB was evaluated in carrageenan-induced paw oedema and neutrophil migration. In order to discard possible non-specific muscle relaxant or sedative effects of MEB, mice motor performance was evaluated in the rota rod test and its toxicity evaluated over 14 days.

Results

Intraperitoneal (IP) administration of MEB (0.01–100 mg/kg) produced a dose-related antinociception on acetic acid-induced writhing in mice. Oral administration of MEB, at a different range of doses (100–400 mg/kg), also produced significant antinociceptive effect on the writhing test. Furthermore, treatment with MEB (100 and 200 mg/kg IP) inhibited significantly both the early and late phases of formalin-induced hypernociception in rats. In contrast, treatment with MEB (100 and 200 mg/kg IP) did not prevent the thermal nociception in the tail flick test. The IP administration of MEB (100 and 300 mg/kg) significantly reduced the paw oedema induced by carrageenan. Moreover, systemic treatment with MEB (11–300 mg/kg) reduced the neutrophil migration in the carrageenan-induced migration to the peritoneal cavity. In the rota rod test, MEB-treated mice did not show any significant motor performance alterations with the dose of 300 mg/kg. In addition, over the study duration of 14 days, there were no deaths or toxic signs recorded in the mice given 100 or 1000 mg/kg of MEB.

Conclusion

The results described here are the first report of pharmacological studies of Blechnum occidentale L. and indicate that this plant has antinociceptive and antiinflammatory activities which support its folk medicine use.     

Antidiabetic activity of Ficus amplissima Smith. bark extract in streptozotocin induced diabetic rats

Ethnopharmacological relevance

Ficus amplissima commonly known as kal-itchchi have a long history of use in Ayurveda, Siddha and Unani herbal preparations in Indian traditional system of medicine. It has been used in folklore medicine for the treatment of diabetes.

Aim

The aim of the present study was to evaluate the effect of methanolic extract of the bark of Ficus amplissima (FAB) in streptozotocin-induced diabetic rats.

Materials and methods

Oral administration of FAB bark at the doses of 50 mg/kg, 100 mg/kg and 150 mg/kg was studied in normal, glucose-loaded and STZ—induced diabetic rats.

Results

The three doses caused significant reduction in blood glucose levels in all the models. The effect was more pronounced in 50 mg/kg and 100 mg/kg than 150 mg/kg. FAB also showed significant increase in serum insulin and body weight. The glycogen content in liver, skeletal muscle, total protein contents were markedly increased and marker enzymes of hepatic function of STZ-induced diabetic rats while there was significant reduction in the levels of serum triglyceride and total cholesterol. FAB also showed significant anti-lipid peroxidative effect in the pancreas of STZ-induced diabetic rats. The anti-diabetic effect of FAB was compared with glibenclamide, a well known hypoglycemic drug. Histological analysis showed the regenerative effect of FAB on the β-cells of diabetic rats.

Conclusion

Results of this experimental study indicated that FAB possessed anti-diabetic and antioxidant activities. Hence it could be used as a natural source of antidiabetic (Type-I) and antioxidant drug.     

MAO-A inhibitory activity of quercetin from Calluna vulgaris (L.) Hull.

Aim of the study

This study investigated MAO-A inhibitory activity of methanol extract of Calluna vulgaris (L.) Hull., which traditionally has been used as a nerve calming remedy.

Materials and methods

A methanolic extract of Calluna vulgaris was partitioned against heptane, ethyl acetate and water. The three fractions were tested in a photometric peroxidase linked MAO-A bioassay. The ethyl acetate phase showed the highest MAO-A inhibitory activity. Quercetin was isolated by VLC through bioassay-guided fractionation and purified by re-crystallisation. The structure was elucidated by LC–MS and ¹H NMR.

Results

The IC₅₀-value for MAO-A inhibition by quercetin was 18 ± 0.2 μM in an assay where the IC₅₀-value for MAO-A inhibition by clorgylin was 0.2 ± 0.02 μM.

Conclusion

The content of quercetin in Calluna vulgaris might explain the reported nerve calming effect of the plant.     

Pharmacokinetics of 8-O-acetylharpagide and harpagide after oral administration of Ajuga decumbens Thunb extract in rats

Ethnopharmacological relevance

Ajuga decumbens Thunb is a medicinal plant native to China popularly used to treat chronic pelvic inflammation and hysteromyoma. Its main bioactive components are iridoid glycosides, such as 8-O-acetylharpagide and harpagide that had presented antibacterial, anti-inflammatory, and antiviral activities.

Aim of the study

To establish a sensitive LC–MS/MS method and compare the pharmacokinetics of 8-O-acetylharpagide and harpagide in rats after oral administration of their pure forms and from compounds obtained from Ajuga decumbens extract.

Materials and methods

Rats received orally 15 mg/kg (equivalent of 6 mg/kg 8-O-acetylharpagide and 1.5 mg/kg harpagide), 30 mg/kg and 60 mg/kg of Ajuga decumbens Thunb extract and were compared to animals that received 12 mg/kg of 8-O-acetylharpagide or 3 mg/kg of harpagide p.o. Concentrations of 8-O-acetylharpagide and harpagide in plasma were determined by LC–MS/MS method at different time points and all pharmacokinetic parameters were estimated by non-compartmental analysis.

Results

Results showed that the iridoid glycosides were quickly absorbed by oral route and showed a dose-dependence profile. Pharmacokinetic parameters of both glycosides were essentially the same except Tmax when dosed as the extract or pure forms.

Conclusion

8-O-acetylharpagide was metabolized to harpagide, which affected the pharmacokinetic profiles of harpagide when dosed as the extract. This pharmacokinetic study seems to be useful for a further clinical study of Ajuga decumbens Thunb extract.     

Mast cell stabilizing effects of Sphaeranthus indicus

Aim of the study

We investigated the effects of Sphaeranthus indicus on mast cell stabilizing activity to provide scientific basis for the clinical use of S. indicus.

Materials and methods

The protective effect of different extracts of whole plant of S. indicus against compound 48/80 and sheep serum induced mast cell degranulation was evaluated.

Results

Ethanol extract of S. indicus at the doses of 150 mg/kg and 300 mg/kg and ethyl acetate extract at the dose of 100 mg/kg, 150 mg/kg and 300 mg/kg showed slightly better protection of mast cell degranulation (77–86%) than the standard drug ketotifen (75%) in the sheep serum model. These extracts also showed better mast cell stabilizing activity (77–88%) than the standard drug (69%) when peritoneal mast cells are treated with compound 48/80.

Conclusion

These results suggest that S. indicus has potent mast cell stabilizing effects thereby inhibiting mediator release from mast cells.     

Anticonvulsant,anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata Fresen.

Aim of the study

The objective of this study is to investigate the anticonvulsant, anxiolytic and sedative activities of the aqueous root extract of Securidaca longepedunculata.

Materials and methods

The anticonvulsant effect of the aqueous root extract (100, 200 and 400 mg/kg) was evaluated in mice using the strychnine- and picrotoxin-induced seizure models. Its anxiolytic activity was evaluated using the elevated plus maze (EPM) and the Y maze (YM) methods (14 and 32) while the hexobarbitone induced sleep and the hole board models were used to evaluate the sedative and exploratory activities in mice respectively. The acute toxicity studies and phytochemical analysis of the extract were also carried out.

Results

The extract (100–400 mg/kg) produced a significant (P < 0.01) dose dependent increase in onset of convulsion compared to the control for strychnine- and picrotoxin-induced seizures. It also produced a significant (P < 0.01) dose dependent prolongation of the cumulative time spent in the open arms of the elevated plus maze and Y maze compared with the control. The extract (100–400 mg/kg) produced significant (P < 0.01) reduction in the time of onset of sleep induced by hexobarbitone. The prolongation of hexobarbitone sleeping time by the extract (200 mg/kg) was comparable to that produced by diazepam (3 mg/kg). At doses of 100–400 mg/kg, the extract produced a dose dependent decrease in exploratory activity of the mice. The reduction in exploratory activity produced by the extract (400 mg/kg) was greater than that of chlorpromazine (1 mg/kg). The results obtained from the experiments indicate that the extract has central nervous system depressant and anxiolytic activities. The LD₅₀ obtained for the acute toxicity studies using both oral and intraperitoneal routes of administration were 1.74 g/kg and 19.95 mg/kg respectively.

Conclusion

These findings justify the use of Securidaca longepedunculata in traditional medicine for the management of convulsion and psychosis.     

Anti-inflammatory and antioxidant properties of hydroalcoholic crude extract from Casearia sylvestris Sw. (Salicaceae)

Ethnopharmacological relevance

Casearia sylvestris Sw. is widely used in popular medicine to treat inflammatory conditions.

Aim of the study

To investigate the anti-inflammatory and antioxidant properties of hydroalcoholic crude extract (HCE) taken from Casearia sylvestris Sw. (Salicaceae).

Methods and results

The effect of the HCE from this plant (3–300 mg/kg) on the reduction of inflammatory response to carrageenan was investigated in pleurisy in rats (intrapleural, 2% in 0.2 mL) or paw edema in mice (intraplantar, 300 μg/20 μL, right hind paw). The plant anti-inflammatory action was assessed by its capability in inhibiting cell migration, enzymatic activity of myeloperoxidase (MPO) and production of nitrite/nitrate or edema. The in vitro antioxidant activity of this extract against lipid peroxidation and damage to proteins was assessed as possible pathways to contribute as anti-inflammatory mechanisms. Carrageenan-induced hind paw edema (739.3±11.9 μm) was reduced by HCE (30 mg/kg: 462.8±28.38 μm) to similar extents as dexametasone (365.1±16.7). In pleurisy, treatment of the animals with HCE (100 mg/kg: 0.010±0.001 mU/mg of protein) also reduced MPO activity augmented by carrageenan (0.020±0.001 mU/mg of protein) as well as leukocytes migration (carrageenan: 17.8890±2.3900 leukocytes/mL, HCE 100 mg/kg: 7.0880±9631 leukocytes/mL). Significant effects were also observed in animals treated with different doses of HCE in biochemical tests for oxidative stress analysis.

Conclusion

The anti-inflammatory and antioxidant effects of HCE from Casearia sylvestris Sw. suggests a potential therapeutic benefit of this plant in treatment of inflammatory conditions.     

In vitro and in vivo aphrodisiac properties of Corchorus depressus Linn. on rabbit corpus cavernosum smooth muscle relaxation and sexual behavior of normal male rats

Ethnopharmacological relevance

Corchorus depressus Linn. has been used as an aphrodisiac in traditional Indian medicine to treat male sexual dysfunction and impotency.

Aim of the study

The petroleum ether, chloroform, ethyl acetate, n-butanol and aqueous fractions of 95% methanol extract of Corchorus depressus were screened initially for their in vitro aphrodisiac activity on rabbit corpus cavernosum smooth muscle. The chloroform fraction (CDC) was found to be the most active and therefore investigated further on general mating behavior, libido and potency of normal male Wistar albino rats in comparison with the standard drug, Sildenafil citrate.

Materials and methods

Animals were divided into the following groups: Control, SC CDC 100, CDC 200, and CDC 400, who received saline, Sildenafil citrate or the chloroform fraction of Corchorus depressus at doses of 100, 200 or 400 mg/kg b.wt., respectively. The route of administration for all the groups was oral dosing, which was once in a day for 45 days. To analyze the mating behavior, female rats with estrus phase were used.

Results

The chloroform fraction of methanolic extract of Corchorus depressus significantly reduced ML, IL, PEI and III. There was a significant increase in the MF, IF and EL and serum testosterone levels throughout the study period. The potency test significantly increased erections, quick flips, long flips and total reflex. In vitro aphrodisiac activity was significantly higher in chloroform fraction at a concentration of 25.0 mg/ml, which induced 71.4% relaxation. The combined results of the above mentioned models indicate that the chloroform fraction of Corchorus depressus produces a significant increase in sexual activity as exhibited by 25 mg/ml in vitro and 400 mg/kg in vivo. In comparison with the control, all the drug-treated groups have shown drug-induced effects for a few parameters.

Conclusions

In vitro and in vivo studies provide valuable experimental evidence that the chloroform fraction of methanolic extract of Corchorus depressus possesses aphrodisiac property. This study further substantiates the ethnopharmacological claims of Corchorus depressus as a sexual stimulating agent and offers a significant potential for studying the effect on male sexual response and its dysfunctions.     

Evaluation of the anti-stress and anticonvulsant activities of leaf extract of Alchornea cordifolia in mice

Aim of the study

The extract of the leaves of Alchornea cordifolia (AC) is extensively used in ethnomedicine for ulcers, rheumatic pains, febrile convulsions and for enhancing physical performance. In this study, the anti-stress and anticonvulsant activities of the aqueous leaf extract of Alchornea cordifolia were investigated in mice.

Materials and methods

The anti-stress activity was assessed based on the ability of the extract to alter the duration of immobility, in the forced swim endurance test, whilst a picrotoxin-treated animal, was employed as the model for convulsive seizures.

Results

The extract (100–400 mg/kg) given orally was found to significantly (p < 0.05) reduce the duration of immobility, which suggest an anti-stress/anti-fatigue property. However, AC when tested at doses between 100 and 400 mg/kg did not prevent convulsions induced by picrotoxin in mice. The acute toxicity study carried out in mice revealed that the extract was well tolerated by the animals, as no death was observed at oral doses of 500–4000 mg/kg.

Conclusions

The results of this preliminary study provide evidence, which may support the use of Alchornea cordifolia against stress or fatigue in ethnomedicine.     

Effects of mitragynine from Mitragyna speciosa Korth leaves on working memory

Aim of the study

Mitragyna speciosa Korth from Rubiaceae family is a tropical plant indigenous to Southeast Asia particularly in Thailand, Peninsular of Malaysia and Indonesia. The leaves have been used by natives for their opium-like effect and cocaine-like stimulant ability to combat fatigue and enhance tolerance to hard work. However there is no scientific information about the effect of mitragynine on the cognitive performances. This study is designed to examine the working memory effects of mitragynine which is extracted from Mitragyna speciosa mature leaves.

Materials and methods

The cognitive effect was studied using object location task and the motor activity in open-field test. Mitragynine 5, 10 and 15 mg/kg and were administered by intraperitoneal (IP) for 28 consecutive days and evaluated on day 28 after the last dose treatment. Scopolamine was used as the control positive drug.

Results

In this study there is prominent effects on horizontal locomotor activity was observed. Mitragynine significantly reduced locomotor activity in open-field test compared with vehicle. In object location task mitragynine (5, 10 and 15 mg/kg) did not showed any significances discrimination between the object that had changed position than the object that had remain in a constant position.

Conclusion

Our results suggest that chronic administration of mitragynine can altered the cognitive behavioral function in mice.     

Evaluation of the diuretic and analgesic activities of the rhizomes of Rumex abyssinicus Jacq in mice

Aim of the study

Rumex abyssinicus Jacq (Polygonaceae) has been used traditionally for treatment of hypertension, inflammatory and painful conditions in Ethiopia. The present study aimed to evaluate the diuretic and analgesic activities of extracts of Rumex abyssinicus at different doses in mice.

Materials and methods

The effect on urine volume and urinary electrolyte (Na⁺, K⁺ and Cl⁻) was assessed for a period of 5 h following oral administration of aqueous (500 mg/kg, 750 mg/kg or 1000 mg/kg) or 80% methanolic (250 mg/kg, 500 mg/kg or 750 mg/kg) extract or furosemide (10 mg/kg). Acetic acid-induced writhing and hot-plate tests were employed to study the analgesic effect of 80% methanolic extracts (250 mg/kg, 500 mg/kg or 1000 mg/kg, P.O.) and compared with that of aspirin (100 mg/kg, P.O.) or morphine (10 mg/kg, sc).

Results

The extracts displayed dose-dependent diuretic and analgesic effects. The highest doses of both extracts markedly and significantly increased (P < 0.001) urine volume and urinary electrolytes, qualitatively similar to that of furosemide. 1000 mg/kg of the extract reduced the number of writhing by 67.6% (P < 0.001) and conferred more than 70% protection against thermally induced pain stimuli after 45 min of treatment comparable to that of aspirin and morphine, respectively.

Conclusion

These findings collectively indicate that the extracts exhibited significant diuretic and analgesic activities, providing evidence, at least in part, for its folkloric use.     

Antitubercular constituents from Premna odorata Blanco

Ethnopharmacological relevance

Premna odorata Blanco (Lamiaceae) is a medicinal plant traditionally used in Albay Province, in southeastern Luzon, Philippines to treat tuberculosis. This study aimed to determine the antitubercular property of the crude extract and sub-extracts of the leaves, and to isolate the bioactive principles from the active fractions.

Materials and methods

Through extraction, solvent polarity-based fractionation and silica gel chromatography purification of the DCM sub-extract, compound mixtures from the bioactive fractions were isolated and screened for their in vitro antimycobacterial activity against Mycobacterium tuberculosis H₃₇Rv using the colorimetric Microplate Alamar Blue assay (MABA).

Results

The crude methanolic extract and sub-extracts showed poor inhibitory activity against Mycobacterium tuberculosis H₃₇Rv (MIC≥128 µg/mL). However, increased inhibitory potency was observed for fractions eluted from the DCM sub-extract (MIC=54 to 120 µg/mL). Further purification of the most active fraction (MIC=54 µg/mL) led to the isolation of a 1-heneicosyl formate (1), 4:1 mixture of β-sitosterol (2), stigmasterol (3) and diosmetin (4), which were identified through GC–MS analysis (with dereplication) and NMR experiments. The MIC of compound 1 was 8 µg/mL.

Conclusions

The results of this study provide scientific basis for the traditional use of Premna odorata as treatment for tuberculosis.