Studies on the possible mechanisms of antidiabetic activity of extract of aerial parts of Phyllanthus niruri.

CONTEXT/OBJECTIVES: The effects of methanol extract of aerial parts of Phyllanthus niruri L. (Euphorbiaceae), an antidiabetic herb, on glucose absorption and storage in diabetes were studied to elucidate the mechanisms of blood glucose lowering and glycemic control in diabetes. METHODS: The effect of chronic oral administration of the extract on glycemic control was evaluated in alloxan diabetic rats using blood glucose lowering and post-prandial glucose suppression activities as well as effects on hemoglobin glycation and body weight. Effects on glucose mobilization and storage were assessed using the weight and glycogen content of liver isolated from treated diabetic rats, while in vitro inhibition of α-amylase and α-glucosidase enzyme activities were used as indices of effect on glucose absorption. RESULTS: Results showed that the extract lowered blood glucose, suppressed postprandial rise in blood glucose following a glucose meal, reduced hemoglobin glycation and increased absolute and relative weights as well as glycogen content of liver in diabetic rats. Treatment with the extract also ameliorated the decrease in body weights caused by the diabetic disease. In vitro, the extract inhibited α-amylase (IC50: 2.15 ± 0.1 mg/mL) and α-glucosidase (IC50: 0.2 ± 0.02 mg/mL) activities. DISCUSSION AND CONCLUSION: These findings suggest that aerial parts of P. niruri may owe their blood glucose lowering properties to inhibition of glucose absorption and enhancement of glucose storage.

Medicinal Plants Used in Wound Care: A Study of Prosopis africana (Fabaceae) Stem Bark.

The effects of the methanol extract of the stem bark of Prosopis africana (Guill., Perrott. and Rich.) Taubert (Fabaceae) on bleeding/clotting and coagulation time, excision and dead space wounds were studied in rats. Also, the extract was subjected to antibacterial, and acute toxicity and lethality (LD(50)) tests. The extract significantly (P<0.05) reduced bleeding/clotting and coagulation time in rats. It also reduced epithelialization period of excision wounds in rats and inhibited the growth of laboratory strains of Staphylococcus aureus, Bacillus subtilis, Salmonella typhi, Pseudomonas aeruginosa and Klebsiella pneumoniae to varying extents. Acute toxicity and lethality (LD(50)) test on the extract established an LD(50) of 774 mg/kg (i.p) in mice while phytochemical analysis gave positive reactions for alkaloids, saponins, tannins, flavonoids, steroids, terpenoids and carbohydrates. The results of this study demonstrate the beneficial effects of the stem bark of P. africana in wound care.

The effects of Phyllanthus niruri aqueous extract on the activation of murine lymphocytes and bone marrow-derived macrophages.

Phyllanthus niruri L. (Euphorbiaceae) is acclaimed world-wide for its versatile ethnomedicinal uses. It features in recipes used by some herbalists to manage different diseases, including claims of efficacy against many life-threatening infections, such as HIV/AIDS and hepatitis. In order to understand the mechanisms and the involvement of the immune system in mediating these activities, the effects of the aqueous extract of P. niruri on the activation of murine lymphocytes and macrophages were investigated. The study showed that the extract of P. niruri is a potent murine lymphocytes mitogen, inducing significant (p < 0.01) increases in the expression of surface activation maker (CD69) and proliferation of B and T lymphocytes. The production of interferon-gamma (IFN- gamma) and interleukine-4 (IL-4) by P. niruri extract-stimulated naïve splenocytes cultures was also significantly (p < 0.05) increased in a concentration-dependent manner. Various indices of activation and functions murine bone marrow-derived macrophages were significantly (p < 0.05) enhanced by pre-treatment with the extract, including phagocytosis, lysosomal enzymes activity, and TNF-alpha release. Phyllanthus niruri extract was also shown to modulate nitric oxide release by macrophages. These activities suggest that stimulation of the immune system by the extracts of P. niruri could be partly responsible for the ethnomedicinal applications in the management of infectious diseases.

Anticonvulsant and anxiolytic evaluation of leaf extracts of Ocimum gratissimum, a culinary herb.

Anticonvulsant and anxiolytic activities of leaf extracts and fraction of Ocimum gratissimum L. (Lamiaceae) were studied using seizures induced by pentylenetetrazol and open-field tests in mice. The results showed that the extracts and fraction increased the latency of tonic and tonic-clonic seizures and death and elicited 50% protection against mortality. In the open-field test, the extracts and fraction decreased the frequency of line crossing, center square entries, rearing against a wall and grooming, whereas grooming duration and freezing frequency and duration were increased. Acute toxicity test in mice gave an oral LD(50) greater than 5000 mg/kg for the methanol extract. These findings suggest that extracts of this plant possess anticonvulsant and anxiolytic-like properties.

Antiulcer activity of roots of zapoteca portoricensis (fam. Fabiaceae).

BACKGROUND: The roots of Zapoteca portricensis is a common remedy in the treatment gastrointestinal disorders used by tradomedical practitioners in Eastern Nigeria. AIM: This study was aimed at evaluating the possible antiulcer activity of the root of this plant in experimental rats. METHODS: A methanolic root extract was prepared by cold maceration. Antiulcer activity was tested using absolute ethanol and indomethacin induced ulcer models. Sucralfate (100 mg/kg oral) was used as the reference drug. Different groups of albino rats of male sex were given three doses (50, 100, 200 mg/kg) of the extract. Phytochemical analysis of the freshly dried roots was also done. RESULTS: Phytochemical results revealed presence of alkaloids, terpenoids, glycosides and flavonoids. The ethanol model produced an average ulceration in rats with reduction of ulcer (50%, 75% and 90%) seen in all the extract treatment. A dose dependent inhibition of ulcer was seen in all doses of the extract with doses 100 and 200 mg/kg produced a significant reduction compared with control. In the indomethacin model, an absolute ulceration was produced in all the animals. Inhibition of ulcer (57.1%, 65.7% and 80.0%) was seen in the treatments with the extracts in a dose dependent manner. All the three doses of the extracts produced significant ulcer protection compared with control. CONCLUSION: This study has shown that roots of this plant (Zapoteca portoricensis) possess potent antiulcer activity.

Carica papaya (Paw-Paw) unripe fruit may be beneficial in ulcer.

The anti-ulcer potentials of aqueous (AE) and methanol (ME) extracts of whole unripe Carica papaya fruit were evaluated using ethanol- and indomethacin-induced gastric ulcer models in rats. The effect of the extracts on small intestinal propulsion was also investigated. The extracts significantly reduced the ulcer index in both experimental models (P < .05) compared to the control group. ME showed a better protection against indomethacin-induced ulcers, whereas AE was more effective against ethanol-induced gastric ulcers. The extracts also significantly (P < .05) inhibited intestinal motility, with ME showing greater activity. Oral administration of AE and ME up to 5,000 mg/kg did not produce lethality or signs of acute toxicity in mice after 24 hours. The extracts of unripe C. papaya contain terpenoids, alkaloids, flavonoids, carbohydrates, glycosides, saponins, and steroids. The cytoprotective and antimotility properties of the extracts may account for the anti-ulcer property of the unripe fruit.

Immunomodulatory activities of kolaviron, a mixture of three related biflavonoids of Garcinia kola Heckel.

The immunomodulatory properties of kolaviron (KV), a mixture of three related biflavonoids of Garcinia kola Heckel (Clusiaceae), were investigated. The study was conducted using in vitro and in vivo immunocompetent and immunocompromised animal models. KV (250 and 500 mg/kg) produced a dose-dependent and significant (p < 0.05) inhibition of delayed-type hypersensitivity in rats and also caused a significant (p < 0.05) increase in the primary and secondary sheep erythrocytes-specific antibody titres in rats. In vitro, KV inhibited the classical complement system at concentrations greater than 100 microg/ml. The administration of KV ameliorated the cyclophosphamide-induced leukopenia and increased the proportion of lymphocytes count in rats after 14 days of treatment. Administration of KV on alternate days after immunosuppression with cyclophospamide increased the rate of excision wound closure and reduced epithelialization period from 21.75 to 15.5 days. This study established the immunomodulatory and immunorestorative properties of KV, which could be harnessed for possible clinical benefits to immunodeficient patients.

Potentials of leaves of Aspilia africana (Compositae) in wound care: an experimental evaluation.

BACKGROUND: The potentials of the leaves of the haemorrhage plant, Aspilia africana C. D Adams (Compositae) in wound care was evaluated using experimental models. A. africana, which is widespread in Africa, is used in traditional medicine to stop bleeding from wounds, clean the surfaces of sores, in the treatment of rheumatic pains, bee and scorpion stings and for removal of opacities and foreign bodies from the eyes. The present study was undertaken to evaluate the potentials for use of leaves of this plant in wound care. METHODS: The effect of the methanol extract (ME) and the hexane (HF) and methanol (MF) fractions (obtained by cold maceration and graded solvent extraction respectively) on bleeding/clotting time of fresh experimentally-induced wounds in rats, coagulation time of whole rat blood, growth of microbial wound contaminants and rate of healing of experimentally-induced wounds in rats were studied as well as the acute toxicity and lethality (LD50) of the methanol extract and phytochemical analysis of the extract and fractions. RESULTS: The extract and fractions significantly (P < 0.05) reduced bleeding/clotting time in rats and decreased coagulation time of whole rat blood in order of magnitude of effect: MF>ME>HF. Also, the extract and fractions caused varying degrees of inhibition of the growth of clinical isolates of Pseudomonas fluorescens and Staphylococcus aureus, as well as typed strains of Ps. aeruginosa (ATCC 10145) and Staph. aureus (ATCC 12600), and reduced epithelialisation period of wounds experimentally-induced in rats. Acute toxicity and lethality (LD50) test in mice established an i.p LD50 of 894 mg/kg for the methanol extract (ME). Phytochemical analysis revealed the presence of alkaloids, saponins, tannins, flavonoids, resins, sterols, terpenoids and carbohydrates. CONCLUSION: The leaves of A. africana possess constituents capable of arresting wound bleeding, inhibiting the growth of microbial wound contaminants and accelerating wound healing which suggest good potentials for use in wound care.

Anti-inflammatory activity of hexane leaf extract of Aspilia africana C.D. Adams.

The anti-inflammatory activity of hexane leaf extract of Aspilia africana C.D. Adams (Compositae) was evaluated in rodents using the xylene-induced ear edema, egg albumin- and agar-induced paw edema, formaldehyde-induced arthritis, cotton pellet granuloma, gastric ulcerogenic, acetic acid-induced vascular permeability and dextran-induced in vivo leukocyte migration tests. Results showed that the extract (5mg/ear) inhibited topical edema in the mouse ear and at 200 and 400mg/kg (i.p.), it significantly (P<0.05) suppressed the development of egg albumin- and agar-induced paw edema, and the global edematous response to arthritis induced by formaldehyde in rats. Oral administration of the extract (200 or 400mg/kg) evoked a significant (P<0.05) dose-related ulceration of the rat gastric mucosa and inhibition of vascular permeability induced by acetic acid in mice. The extract also significantly (P<0.05) reduced total leukocyte and neutrophils counts in a non-dose-related manner. However, it significantly (P<0.05) increased lymphocyte counts and stimulated the growth of granuloma tissues induced by subcutaneously implanted cotton pellets in rats. Phytochemical tests showed that the extract contained sterols and terpenoids. These findings suggest that the leaves of Aspilia africana possess anti-inflammatory activity in acute and certain aspects of chronic inflammation, which may derive from inhibition of prostaglandins synthesis, inhibition of increased vascular permeability, inhibition of neutrophil migration into inflamed tissues, and stimulation of lymphocyte accumulation, which may enhance tissue repair and healing. The terpenoids present in the leaves may account for the anti-inflammatory activity.

Analgesic activity of leaf extracts of Culcasia scandens P. Beauv.

Analgesic activity of methanol leaf extract of C. scandens obtained by column chromatography and its graded solvent fractions, was evaluated in mice using acetic acid-induced abdominal writhing and formalin-induced paw licking. The extract and fractions significantly inhibited abdominal writhing and two phases of formalin-induced paw licking in mice, indicating that antinociceptive activity may involve inhibition of pain by peripheral and central mechanisms.

Anti-inflammatory activity of extracts of root bark of securidaca longipedunculata Fres (Polygalaceae)

The effect of extract and fractions of the root bark of Securidaca longipedunculata Fres (Polygalaceae) on acute inflammation was evaluated. Solvent extraction yielded the crude methanol extract (ME) while solvent-guided extraction yielded a petroleum ether fraction (PF) and methanol fraction (MF). The extract and fractions inhibited topical edema induced by xylene in the mouse ear. In the systemic edema of the rat paw; the methanol extract (ME) and methanol fraction (MF) significantly (P0.05) suppressed the development of paw edema induced by egg albumin in rats while the petroleum ether fraction (PF) was devoid of such activity. Ulcerogenic assay in rats indicated that the extract and fractions exhibited varying degrees of gastric irritation in rats in the order of magnitude: MF PF ME. Phytochemical tests showed that ME and MF tested positive for carbohydrates; reducing sugars; glycosides; flavonoids; terpenoids; sterols and saponins while PF gave positive reaction for resins only. Acute toxicity test for ME in mice established an i.p and p.o LD50 of 11 and 282 mg/kg respectively

Postsynaptic dopamine (D(2))-mediated behavioural effects of high acute doses of artemisinin in rodents.

Artemisinin or qinghaosu is the active principle of quinghao (Artemisia annua L.) developed from Chinese traditional medicine, which is now widely used around the world against falciparum malaria. Behavioural effects of high acute doses of artemisinin were studied on spontaneous motor activity (SMA), exploratory behavior, apomorphine-induced stereotype behavior and pentobarbital sleeping time in mice and rats in order to provide additional evidence on its safety profile on the central nervous system (CNS). Effects of the drug on bromocriptine-induced hyperactivity in short term reserpinised mice were also evaluated. Intraperitoneal (i.p.) injection of artemisinin at doses of 50 and 100mg/kg, significantly (P<0.05) reduced the SMA in mice, prolonged the pentobarbital sleeping time in rats, and attenuated the apomorphine-induced stereotypy in mice. Mice pretreated with reserpine, showed a significant decrease in locomotor activity compared to the saline-treated group. Bromocriptine, a D(2) receptor agonist, induced locomotor activity in mice pretreated with reserpine which was attenuated by artemisinin. The results suggest that artemisinin possesses sedative property, which may be mediated via postsynaptic dopamine (D(2)) receptor in the CNS.

Evaluation of the anti-asthmatic property of Asystasia gangetica leaf extracts.

The leaf of Asystasia gangetica T. Adams (Acanthaceae) is used in many parts of Nigeria for the management of asthma. This study was aimed at investigating the anti-asthmatic property of hexane, ethylacetate, and methanol extracts of the leaves of Asystasia gangetica, obtained by successive sohxlet extraction. The results indicated that the extracts did not exhibit contractile or relaxant activity in isolated tissue preparations; however, they inhibited the contraction evoked by spasmogens; the IC(50) were calculated, where possible. The extracts relaxed histamine-precontracted tracheal strips in the following degree of potency-ethylacetate extract>hexane extract=methanol extract. The extracts also exhibited anti-inflammatory activity in the order of magnitude-methanol extract>hexane extract>ethylacetate extract. Acute toxicity test estimated an i.p. LD(50) of 2150 mg/kg in mice for methanol extract while phytochemical screening showed the presence of carbohydrates, proteins, alkaloids, tannins, steroidal aglycones, saponins, flavonoids, reducing sugars, and triterpenoids, with the methanol extract having the highest number of constituents. The study justified the use of the leaf of Asystasia gangetica in the management of asthma in Nigerian folk medicine.

Smooth muscle contraction induced by Indigofera dendroides leaf extracts may involve calcium mobilization via potential sensitive channels.

The contractile effects of the aqueous extract of the leaves of Indigofera dendroides (ID) were studied on the gastrointestinal motility in mice and isolated smooth muscle preparations obtained from rats and guinea pigs. The contractile effects of 10(-6) M acetylcholine, 80 mM KCl and 1.6 mg/ml ID were measured on the rat ileal smooth muscle exposed to calcium-free buffer or physiological solution, to determine the calcium pools mobilized by extract for activation of contraction. Acute toxicity test (LD(50)) was also carried out in mice. The result showed that ID (0.05-3.2 mg/ml) produced a concentration-dependent contraction of the guinea pig and rat ileum. These responses were not blocked by mepyramine (2.49 x 10(-9) M), verapamil (8.14 x 10(-9) M), or pirenzepine (4.7 x 10(-7) M), but were blocked completely by atropine (2.92 x 10(-9) M). A significant increase in propulsion of gastrointestinal motility was observed. Acetylcholine, KCl and ID produced contractions in Ca(2+) free media. The phasic components of the contractile responses to Ach as well as the tonic component of K(+) and ID-induced contractions were relatively resistant to short periods of calcium-free exposure. Ach, K(+) and ID still caused contractions in the presence of verapamil. The data revealed that ID-induced contractions were not mediated by histaminergic receptors, calcium channels, M1 muscarinic receptors. It also suggests that Ach mobilize Ca from some tightly bound or intracellular pool, whereas high K(+) and ID may mobilize Ca from some superficial or loosely-bound pool.

Effect of the aqueous extract of Chrysanthellum indicum on calcium mobilization and activation of rat portal vein.

The effects of the aqueous extract of Chrysanthellum indicum (CI) on calcium activation and mobilization were studied using the rat portal vein. The extract caused a concentration-dependent contraction of the portal vein. KCl (80 mM), norepinephrine (NA, 10(-6)M) and CI (4 mg/ml) evoked sustained contraction of the portal vein. In Ca-free medium (with EGTA) the contractions evoked by these agents were reduced significantly. The times-to-peak of KCl, NA and CI were similar -in normal PSS, but in Ca-free medium the times-to-peak for KCl and CI were greatly increased. The contractions induced by CI were not inhibited by chlorpropamide and prazosin, but were blocked by verapamil. The data obtained suggest that the aqueous extract of CI utilizes extracellular calcium pools to bring about contractile response and this effect might be mediated through the activation of potential-sensitive channels.

Effect of methanolic leaf extract of Cissampelos mucronata A. Rich against indomethacin induced ulcer in rats.

Five fractions (F1-F5) isolated from the methanolic leaf extract of Cissampelos mucronata A. Rich were investigated for antiulcer activity. At the dose of 450 mg/kg, they showed varying degree of protection against ulcer induced by indomethacin; the order of protection being F1>F4>F5>F2>F3. The antiulcer potency of F1 and F2 is comparable with that of cimetidine (100 mg/kg, i.p.). Inhibition of gastric mucosal damage may partly contribute to the antiulcer activity of the fractions.

Evaluation of the sedative properties of the ethanolic root extract of Cissampelos mucronata.

The ethanolic root extract of Cissampelos mucronata was investigated for sedative activity. Phytochemical analysis indicated the presence of alkaloids: sterols/triterpenes, tannins, carbohydrates, glycosides, and flavonoids. Acute lethality test gave an LD50 of 282.84 mg/kg. The study of the effect of the extract on the behavioural pattern of mice showed changes indicative of central nervous system depression. The results further revealed that the extract progressively reduced ephedrine-induced spontaneous motor activity in rats, and prolonged pentobarbitone-sleeping time in mice. Pre-treatment of mice with the extract also protected 40% of the animals against pentylenetetrazole-induced convulsions. The mechanism of action is not precisely known but may probably be attributed to central nervous system depressant action.

Anti-inflammatory, analgesic and anti-lymphocytic activities of the aqueous extract of Crinum giganteum.

The anti-inflammatory, anti-lymphocytic and analgesic properties of Crinum giganteum, a popular herb used for the management of asthma and other respiratory disorders was investigated in rats and mice. The extract dose-dependently produced significant (P<0.05) inhibition of formalin induced pain in rats. It also demonstrated significant (P<0.01) inhibition of abdominal constriction induced with 0.75% v/v acetic acid in mice. On the cotton pellet induced granulomatous tissue formation in rats, the extract significantly (P<0.05) decreased the weight. However, no significant inhibition was observed in the egg albumin-induced inflammation in rats. Oral administration of this extract in rats for 14 days significantly affected (P<0.05) the total leukocyte count and the overall percentage lymphocytes. The intraperitoneal and per oral LD(50) were 627+/-5.8mg/kg and 1486+/-18.9 mg/kg in mice and 520+/-10.2mg/kg and 1023+/-4.3 mg/kg in rats, respectively. Preliminary phytochemical analysis of the extract indicates the presence of tannins. These results therefore indicate that C. giganteum bulb contains biologically active principles, which have potentials for the treatment of inflammatory processes.

Anthelmintic activity of the stem bark extracts of Berlina grandiflora and one of its active principles, Betulinic acid.

This study examines the anthelmintic activity of a methanol, hexane and ethylacetate extracts of Berlina grandiflora and purified betulinic acid, the major triterpenoid found in the extract. Caenorhabditis elegans, a free living soil nematode was used as in vitro model in the study. A suspension of worms was treated with the extracts. After seven days of incubation activity was assessed in terms of number of worms exhibiting motiliy. The results showed that methanol, hexane and ethylacetate fractions at 500 ppm showed anthelmintic activities in the order ethylacetate > methanol > hexane from the alcoholic crude extract. The isolated betulinic acid from the ethylacetate fraction at 100 and 500 ppm showed strong anthelmintic activities comparable to piperazine. These results confirm the traditional use of Berlina grandiflora as an anthelmintic and indicate that betulinic acid is the active component.

A pilot evaluation of the anti-inflammatory activity of Culcasia scandens, a traditional antirheumatic agent.

OBJECTIVE: To screen the anti-inflammatory potentials of a popular traditional antirheumatic herb, Culcasia scandens. DESIGN: The leaves of Culcasia scandens were collected, identified, dried, and reduced to coarse powder and extracted with methanol. The methanol extract was fractionated into seven fractions. The fractions were subjected to phytochemical analysis to identify the biologically active constituents. The anti-inflammatory activity of the crude (methanol) extract (CE) and the fractions were determined in rats. The crude extract was also subjected to acute toxicity tests. RESULTS: The extract was partitioned into seven fractions (F1-F7) using preparative thin layer chromatography. Fraction F1 and the methanol-insoluble fraction (F9) did not exhibit any anti-inflammatory activity. The other fractions showed anti-inflammatory activity in the following order F6> F2> F5> F4> F8> F3> F7> CE. The anti-inflammatory potency of F2 and F6 at the dose tested were greater than that of aspirin (100 mg/kg). Phytochemical analysis of the extracts revealed the presence of reducing sugars, carbohydrates, alkaloids, glycosides, saponins, tannins, flavonoids and an unsaturated lactone ring of steroids. The median lethal dose (LD50) of the crude extract in the mice was greater than 5 g/kg. The results indicate that the leaves of C. scandens have good potential as an anti-inflammatory agent.