Hypotensive effect and toxicology of the extract from Coscinium fenestratum (Gaertn.) Colebr.

The water extract from Coscinium fenestratum (Gaertn.) Colebr. (CF extract) was tested for hypotensive and vasorelaxant effects. Acute and subchronic toxicity as well as motor activity of CF extract were also evaluated. The present study demonstrates that CF extract is effective in reducing blood pressure in anesthetized normotensive rats. This effect is shown to be dose-related and rapid in onset. The extract showed an endothelium-dependent and independent vasorelaxant activity in isolated aortic rings precontracted with phenylephrine (1 microM) and KCl (60 mM). The capacity of L-NAME (100 microM), an inhibitor of nitric oxide synthase, to reduce the vasorelaxant action of the extract indicates the involvement of nitric oxide. In the acute toxicity test, an oral dose of 5000 mg/kg of the CF extract did not produce mortality or significant changes of the general behavior of animals and gross appearance of internal organs of rats. Similarly, in the subchronic toxicity test, an oral dose of 2500 mg/kg/day of the CF extract given to rats for 90 days did not cause any significant change of any of the parameters observed when compared with those of the control animals. Moreover, the CF extract did not produce any effect on the central nervous system when spontaneous motor activity in rats was assessed. However, because some average hematological and blood chemistry values were found to be statistically different, further studies, including chronic toxicity test, should be done to confirm the safety of this plant when it is used over a long period of time.

Toxicity of crude rhizome extract of Kaempferia galanga L. (Proh Hom).

The ethanolic rhizome extract of Kaempferia galanga L. (Zingiberaceae) was studied by conventional pharmacological methods including the Hippocratic screening test, and acute and subacute toxicities in rats. The hexane fraction was tested for dermal irritation in rabbits. The ethanolic extract, when tested by the Hippocratic screening test, demonstrated signs that indicated CNS depression such as a decrease in motor activity and respiratory rate, and a loss of screen grip and analgesia. In the acute toxicity test, oral administration of 5 g/kg of Kaempferia galanga produced neither mortality nor significant differences in the body and organ weights between controls and treated animals. Moreover, both gross abnormalities and histopathological changes were not comparatively detectable between all controls and treated animals of both sexes. In subacute toxicity studies, no mortality was observed when varying doses of 25, 50 or 100 mg/kg of ethanolic Kaempferia galanga extract were administered orally per day for a period of 28 days. There were no significant differences in the body and organ weights between controls and treated animals of both sexes. Hematological analysis showed no differences in any of the parameters examined (WBC count, platelet, hematocrit and hemoglobin estimation) in either the control or treated groups of both sexes. However, the differential leukocyte counts showed a slight but significant decrease of lymphocyte count in the 50 and 100 mg/kg male rat groups. In the blood chemistry analysis, no significant change occurred in the blood chemistry parameters, including glucose, creatinine, blood urea nitrogen (BUN), aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (Alk-P), total protein and albumin of both sexes. Pathologically, neither gross abnormalities nor histopathological changes were observed. No sign of irritation was observed during the dermal irritation test of the hexane fraction of Kaempferia galanga.

Anti-inflammatory and analgesic activities of Mallotus spodocarpus Airy shaw.

The chloroform extract from the roots of Mallotus spodocarpus was investigated for anti-inflammatory and analgesic activities in animal models. In acute inflammatory models, the extract significantly inhibited ethyl phenylpropiolate-induced ear edema and carrageenin- and arachidonic acid-induced hind paw edema in rats. In the chronic inflammatory model using the cotton pellet-induced granuloma in rats, the extract exhibited inhibitory activity on the formation of granuloma. The extract also elicited pronounced inhibitory effect on acetic acid-induced writhing response in mice in the analgesic test. The results obtained suggest marked anti-inflammatory and analgesic activity of the extract.

The analgesic, antipyretic and anti-inflammatory activity of Diospyros variegata Kruz.

Pharmacological studies were conducted with the hexane extract of the dry stem of Diospyros variegata Kruz. (Ebenaceae) on experimental animals for evaluating the analgesic, antipyretic and anti-inflammatory activities. In the analgesic test, the hexane extract elicited inhibitory intensity on acetic acid-induced writhing response and on the late phase of formalin test but possessed only a weak effect on the tail-flick response and on the early phase of formalin test. The hexane extract also elicited antipyretic action when tested in yeast-induced hyperthermia in rats. In addition, the hexane extract showed an anti-inflammatory effect when tested in ethyl phenylpropiolate (EPP)- and arachidonic acid (AA)-induced rat ear edema.

Anti-inflammatory and antipyretic properties of Clerodendrum petasites S. Moore.

The methanol extract from Clerodendrum petasites S. Moore (CP extract) was assessed for anti-inflammatory and antipyretic activities on the experimental animal models. It was found that CP extract possessed moderate inhibitory activity on acute phase of inflammation in a dose-related manner as seen in ethyl phenylpropiolate-induced ear edema (ED(50)=2.34 mg/ear) as well as carrageenin-induced hind paw edema (ED(30)=420.41 mg/kg) in rats. However, CP extract did not elicit any inhibitory effect on arachidonic acid-induced hind paw edema in rats. In subchronic inflammatory model, CP extract provoked a significant reduction of transudation but had no effect on proliferative phase when tested in cotton pellet-induced granuloma model. CP extract also reduced the alkaline phosphatase activity in serum of rats in this animal model. Moreover, CP extract possessed an excellent antipyretic effect when tested in yeast-induced hyperthermic rats. It is postulated that the anti-inflammatory and antipyretic effects of CP extract are caused by the inhibition of the prostaglandin synthesis. Anyhow, CP extract did not possess any analgesic activity in acetic acid-induced writhing response in mice. The results obtained show that C. petasites has beneficial properties since it possesses potent antipyretic and moderate anti-inflammatory activities without ulcerogenic effect.

Anti-inflammatory, antipyretic and antinociceptive activities of Tabernaemontana pandacaqui Poir.

Studies on carrageenin-induced rat paw edema, yeast-induced hyperthermia in rat and writhing response induced by acetic acid in mice showed that the alcoholic extract of stems of Tabernaemontana pandacaqui (T. pandacaqui) has significant anti-inflammatory, antipyretic and antinociceptive activities. These activities are due to alkaloidal components since they were also observed when the crude alkaloidal (CA) fraction separated from alcoholic extract was tested in the same models.

Larvicidal, adulticidal and repellent effects of Kaempferia galanga.

Four fractions of Kaempferia galanga (hexane fraction, dichloromethane fraction 1, dichloromethane fraction 2 and methanolic fraction) were tested for larvicidal activity toward fourth instar Culex quinquefasciatus. The hexane fraction was found to exhibit the highest larvicidal effect with the LC50 of 42.33 ppm. Testing for adulticidal activity, the hexane fraction did not show any promising adulticidal effect. However, it caused a knockdown effect which might be useful as a repellent. It was then tested for repellent activity in human volunteers both in laboratory and field studies. In a laboratory study, the hexane fraction possessed repellency against Aedes aegypti (ED50 value of 30.73 microg/cm2), and provided biting protection for 3 hours. In a field study, it could protect against certain mosquitos, ie, Armigeres subalbatus, Anopheles barbirostris, An. aconitus, Mansonia uniformis, Cx. quinquefasciatus, Cx. gelidus, Cx. tritaeniorhynchus and Ae. aegypti. The hexane fraction did not cause dermal irritation when applied on human skin.

Neuropharmacological activities of the crude alkaloidal fraction from stems of Tabernaemontana pandacaqui Poir.

The crude alkaloidal (CA) fraction from the stem of Tabernaemontana pandacaqui Poir. was studied for its pharmacological activity on the central nervous system (CNS) of animals. The CA fraction was found to produce symptoms of CNS depression in conscious rats and mice, viz. reduction in spontaneous motility, potentiation of pentobarbital sleeping time, prolongation of latency of convulsions induced by pentylenetetrazole and antinociception. However, the fraction could not antagonize oxotremorine-induced tremor. The observations suggest that the CA fraction possesses a CNS depressant activity.

Anti-inflammatory activity of the alkaloid bukittinggine from Sapium baccatum.

The anti-inflammatory and related activities of bukittinggine were evaluated in comparison with reference drugs. The results obtained revealed that bukittinggine exhibited a significant inhibitory effect in carrageenin-induced hind paw edema and adjuvant-induced arthritis in rats. Its anti-inflammatory activity in both test models was comparable to that of acetylsalicylic acid. Bukittinggine also showed an inhibitory effect on the late proliferative phase of the inflammatory process in cotton pellet-induced granuloma formation in rats. In carrageenin-induced rat pleurisy, bukittinggine exhibited marked inhibitory activity on exudative formation, accumulation of leukocytes and on PGE2-like activity in the exudate. Furthermore bukittinggine could significantly reduce fever in yeast-induced hyperthermic rats and possessed analgesic activity comparable to that of acetylsalicylic acid when tested in acetic acid-induced writhing response in mice. However, bukittinggine exhibited only a weak effect in the tail-flick test when compared with morphine. It is likely that bukittinggine possesses a mechanism of anti-inflammatory, analgesic and antipyretic action similar to that of acetylsalicylic acid.

Cardiovascular activity of the crude alkaloidal fraction from Tabernaemontana pandacaqui in the rat.

The effects of a crude alkaloidal (CA) fraction from the stem of Tabernaemontana pandacaqui Poir. on the blood pressure and heart rate were investigated in conscious as well as anesthetized rats. The CA fraction exerted a hypotensive activity in both experimental models. In pentobarbital anesthetized rats, an intravenous administration of the CA fraction caused two consecutive hypotensive and bradycardiac responses. In order to investigate the mechanism of the responses, the effect of the CA fraction on the blood pressure and the heart rate was tested in various experimental animals such as pithed rats, reserpinized rats under pentobarbital anesthesia and atropine- or chlorpheniramine-treated rats under pentobarbital anesthesia. The results obtained suggest that the hypotensive and bradycardiac responses of the first phase might involve cholinergic and central mechanisms, whereas those of the second phase involve mechanisms which are mediated by central, biogenic amines, acetylcholine and histamine.

Ethnobotanical review of medicinal plants from Thai traditional books, Part II: Plants with antidiarrheal, laxative and carminative properties.

A survey of medicinal plants used in Thailand has been made from Thai books on traditional herbal medicine. In this part of the survey, 326 plants with antidiarrheal, laxative and/or carminative properties are described. Information provided for each species includes plant part used, methods of preparation and administration and literature references to Thai books, together with indications of usage in other Southeast Asian countries and of phytochemical work which has been performed.

Cardiovascular effects of Tabernaemontana pandacaqui.

Intravenous injection of ethanolic extracts of the stem, leaf and flower of Tabernaemontana pandacaqui caused hypotension in pentobarbital anesthetized rats. At high doses (100-300 mg/kg), the flower extract showed a transient hypertensive effect preceeding hypotensive activity. The effects of the extracts on the heart rate of anesthetized rats correlated well with the negative chronotropic and inotropic activity observed with isolated atrium. The hypotensive activity was not inhibited by antihistaminic and antimuscarinic agents. The extracts had no effect on the pressor effects induced by norepinephrine or dual carotid occlusion. These results suggest that the hypotensive action of the extracts is not mediated through histaminic and muscarinic receptors stimulation, alpha-adrenoceptor blockade or interference of sympathetic transmission.

Hippocratic screening of ethanolic extracts from two Tabernaemontana species.

Ethanolic extracts of roots, stems, leaves and flowers of Tabernaemontana divaricata and T. pandacaqui were studied by an observational (hippocratic) screening method in rats. Extracts of all plant parts caused sedation, decreased respiration and decreased skeletal muscle tone. Except for the leaf extract of T. pandacaqui, the extracts caused vasodilatation of ear vasculature. Analgesic activity was found for all extracts of both Tabernaemontana species, except for the flower extract of T. divaricata. Lethal doses of the extracts caused the animals to die from respiratory paralysis. Intensity of pharmacological activities was greater with the root and stem extracts. The extracts of T. pandacaqui were more potent than those of T. divaricata.

Postcoital antifertility effect of Mentha arvensis.

A uterotonic fraction of Mentha arvensis (UM-fraction) was tested for antifertility effect in rats. Subcutaneous administration of the UM-fraction to rats pregnant from day 1 to day 10 caused a significant interruption in pregnancy. The effect was pronounced during the post-implantation period. At the effective dose, the UM-fraction did not exhibit significant estrogenic or antigonadotropic activities. However, it enhanced the estrogenic effect of estradiol when administered concurrently.