Selective modulatory effects of the essential oil of Croton zehntneri on isolated smooth muscle preparations of the guinea-pig

The effects of the essential oil of the plant Croton zehntneri (EOCz) in the concentration range 1–200 μg/mL were studied on the mechanical activity of various in vitro smooth muscle preparations of the guinea-pig. In isolated ileum EOCz induced a variable response such that in 57% of tissues basal tone was reduced (EC₅₀ 5 μg/mL) whereas the rest remained unaffected by the oil. In concentrations above 10 μg/mL EOCz induced spontaneous oscillatory contractions in all preparations. In contrast the basal tone of the aorta, portal vein and bladder remained unaltered by the oil. In the portal vein EOCz concentration-dependently inhibited the amplitude of spontaneous contractions (IC₅₀ 109 μg/mL) without reducing frequency, whereas in the bladder such activity was increased by the oil (EC₅₀ 44 μg/mL). In ileum precontracted with 60 mM KCl, EOCz induced a complete and concentration-dependent relaxation with an IC₅₀ value of approximately 26 μg/mL. In contrast EOCz did not relax KCl-induced tone in the aorta or bladder, whilst eliciting less than 20% relaxation of the precontracted portal vein. Thus our data show that EOCz exerts differential modulatory effects on the contractility of various smooth muscles of the guinea-pig. That EOCz appears to selectively relax intestinal smooth muscle may support its use in folk medicine as a gastrointestinal antispasmodic. © 1998 John Wiley & Sons, Ltd.     

Differential antagonistic effect of hydroalcoholic extract from Hymenaea martiana hayne arzeik on kinin and other agonist-induced contractions of the isolated rat uterus and Guinea-pig ileum

This study was undertaken to evaluate the action of the hydroalcoholic extract (HE) from the bark of Hymenaea martiana on bradykinin (BK), lysyl-bradykinin (L-BK), acetylcholine (ACh), angiotensin II (AII), prostaglandin F_2a (PGF_2a), serotonin (5-HT), oxytocin (Ot) and histamine (His)-induced contractions of the isolated rat uterine muscle and guinea-pig ileum. The HE (50–200 μg/mL) added to the bath for 20 min caused a concentration-dependent rightward displacement of BK, L-BK and ACh-induced contractions in the rat uterus, allied to a discrete but significant reduction of maximal responses to the latter two agonists. By contrast, at the same range of concentrations the HE antagonized in a concentration-dependent but noncompetitive manner the contractions induced by AII, but only at high concentrations (200 μg/mL) it significantly inhibited contractions evoked by both PGF_2a and Ot, while contractile responses induced by 5-HT were not affected. In the guinea-pig ileum, the HE of H. martiana (50 and 100 μg/ml) caused a discrete rightward displacement of the BK and ACh concentration—response curves. Higher concentrations of the HE of H. martiana (200 μg/mL) caused a marked depression of BK and ACh-induced maximal responses. These findings show that the active principle(s) presents in the HE from the bark of H. martiana exhibits an interesting pharmacological profile against several neurotransmitter-induced contractions in nonvascular smooth muscles. Such actions may be relevant for supporting, at least in part, the use of this plant in folk medicine.     

Antiviral activity in vitro of Cupressus sempervirens on two human retroviruses HIV and HTLV

A proanthocyanidin polymer fraction (MW 1500–2000 daltons) from Cupressus sempervirens L. (Cupressaceae) exhibited true antiviral activity in vitro against two retroviruses, HIV and HTLV III B. In comparison with AZT no toxicity was observed with PPC at concentrations of 50 μg/mL which exceeded the IC₅₀ values (1.5 to 15 μg/mL for HIV and 5 to 25 μg/mL for HTLV). © 1998 John Wiley & Sons, Ltd.     

Inhibiting Activity of Some Glucoindolalkaloids and Iridoids from Sickingia williamsii on Electrically Induced Contractions of Isolated Guinea-pig Ileum

The present study examined the effects of the extracts (petroleum ether, CHCl₃, CHCl₃/MeOH (9:1) and MeOH), partially purified fractions and pure compounds (mainly alkaloids and iridoids) from Sickingia williamsii on the electrically induced contractions of the isolated guinea-pig ileum. The results of our experiments indicate that CHCl₃/MeOH (9:1) and CHCl₃ extracts, tested at concentrations of 300, 150 and 30 μg/mL, dose-dependently reduced the guinea-pig ileum electrical contractions, whereas MeOH and petroleum ether extracts did not affect it. Furthermore, both the partially purified fractions I–IV each tested at concentrations of 500, 250 and 100 μg/mL from the CHCl₃/MeOH (9:1) extract and some pure compounds (10⁻⁴ M , 5×10⁻⁵ M and 2.5×10⁻⁵ M ) isolated and purified from the above fractions significantly reduced, in a dose dependent manner, the electrical contractions of the ileum. As the active pure compounds possess an indole nucleus or/and an iridoid nucleus in their structures, the inhibitory effects appear to depend on these structures.     

Characterization of an extract from the leaves of Cissampelos sympodialis Eichl. on the spontaneous tone of isolated trachea

An aqueous fraction of the ethanol extract of the leaves (AFL) of Cissampelos sympodialis Eichl. (Menispermaceae) was shown to relax the spontaneous tone of guinea-pig tracheal smooth muscle rings with an IC₅₀ of 20.5 μg/mL. The AFL inhibited cyclic nucleotide phosphodiesterase activity in isolated smooth muscle homogenates and stimulated an increase in intracellular cAMP synthesis in intact cultured smooth muscle cells. A complete inhibition of phosphodiesterase activity in isolated homogenates was almost achieved. These studies indicate that the AFL contains a substance which is a non-selective, but highly potent inhibitor of phosphodiesterase activity. This probably accounts for its effect on the spontaneous tone of guinea-pig tracheal smooth muscle. © 1997 John Wiley & Sons, Ltd.     

In Vitro activities of plant extracts from Saudi Arabia against malaria,leishmaniasis, sleeping sickness and Chagas disease

The in vitro activity of the methanol extracts of 51 plants randomly collected from the Kingdom of Saudi Arabia and some of their fractions (petroleum ether, chloroform, ethyl acetate and aqueous) were evaluated against Plasmodium falciparum, Trypanosoma brucei brucei, T. cruzi and Leishmania infantum, as well as toxicity against MRC‐5 fibroblast cells. Ten crude methanolic extracts that demonstrated potent and adequately selective antiprotozoal activity were subjected to solvent fractionation using petroleum ether, ethyl acetate and chloroform. Only three samples showed promising antiprotozoal activity. Argemone ochroleuca (CHCl₃ fraction) showed pronounced activity against P. falciparum_GHA (IC₅₀ 0.32 μg/mL) and T. cruzi (IC₅₀ 0.30 μg/mL) with low cytotoxicity against MRC‐5 cells (CC₅₀ 11.6 μg/mL). Capparis spinosa (EtOAc fraction) showed pronounced activity against P. falciparum_GHA with an IC₅₀ 0.50 μg/mL in the absence of toxicity against MRC‐5 cell line (CC₅₀ > 30 μg/mL). Heliotropium curassavicum (CHCl₃ fraction) showed similar activity against P. falciparum (IC₅₀ 0.65 μg/mL; MRC‐5 CC₅₀ > 30 μg /mL). These three extracts will be subjected for further extensive studies to isolate and identify their active constituents. Copyright © 2010 John Wiley & Sons, Ltd.     

Inhibitory activity of extracts of Alternanthera brasiliana (amaranthaceae) against the herpes simplex virus

Five extracts from A. brasiliana, obtained through different procedures, showed anti-HSV activity. The best activity was detected in a fraction (B) that was obtained from the crude cold aqueous extract on Sephadex G₁₅. Fraction B showed low cellular toxicity and inhibition from 32.4% to 99.9% at concentrations from 6.2 to 50.0 μg/mL, exhibiting a therapeutic index of 32. Fractions obtained on Sephadex G₁₀₀ and reversed-phase column also showed considerable inhibition. Fraction B did not show any virucidal activity, however, its inhibitory activity was revealed during the later stages of the virus replication cycle. This fraction showed activity on DNA synthesis of infected cells.     

Intestinal myorelaxant and antispasmodic effects of the essential oil of Croton nepetaefolius and its constituents cineole,methyl-eugenol and terpineol

The effects of the essential oil of Croton nepetaefolius (EOCN), a medicinal plant from the north-east of Brazil, and its constituents cineole, methyl-eugenol and terpineol, were studied on intestinal motility in vivo and on in vitro mechanical activity of intestinal smooth muscle. In mice, EOCN (10–100 mg/kg body weight, intragastrically) increased the intestinal transit of charcoal marker delivered to the stomach. This was also observed in animals pretreated with castor oil. In segments of guinea-pig ileum and cardial, pyloral and ileo-caecal sphincters, EOCN preferentially decreased basal tonus compared with the amplitude of spontaneous contractions with EC₅₀ values in the range 0.9 – 16 and 8 – 150 μg/mL respectively. In ileum, EOCN, cineole, methyl-eugenol and terpineol decreased tonus with EC₅₀ values of 16, 322, 9 and 71 μg/mL, respectively, and blocked 60 mM [K⁺]-induced contraction with IC₅₀ values of 18, 419, 12 and 95 μg/mL. The data show that EOCN possesses myorelaxant and antispasmodic properties in vitro, consistent with the use of Croton nepetaefolius in folk medicine as an intestinal antispasmodic. EOCN-induced stimulation of intestinal transit in vivo appears consistent with its in vitro effects, since a preferential decrease in tonus may reduce luminal resistance to bulk flow of intestinal contents. © 1998 John Wiley & Sons, Ltd.     

Herbal medicine Catuama induces endothelium-dependent and -independent vasorelaxant action on isolated vessels from rats,guinea-pigs and rabbits

The present study was designed to examine the vasorelaxant action of the herbal medicine Catuama and the hydroalcoholic extracts (HE) of each plant present in this product and to compare their effects with that caused by acetylcholine (ACh) in intact (⁺E) or in endothelium-rubbed (⁻E) rings of rat thoracic aorta (RA), guinea-pig pulmonary artery (GPPA), guinea-pig mesenteric artery (GPMA), rabbit pulmonary artery (RPA), rabbit mesenteric artery (RMA) precontracted with noradrenaline (NA) or phenylephrine (PE). The extract of Catuama (1-3000 μg/mL) produced graded relaxation of RA, ⁺E or ⁻E, with mean EC₅₀ of 430 μg/mL and ≊ 3000 μg/mL and E_max of 81 % ± 15 % and 47% ± 4 %, respectively. The nitric oxide (NO) synthase inhibitor, N^ω-nitro-L -arginine (L -NOARG, 100 μM ), inhibited in vasorelaxant action (p < 0.05) in RA (⁺E), while indomethacin (3 μM ), propranolol (1 μM ), glibenclamide (1 μM ), methylene blue (10 μM ) and apamin (0.1 μM ) had no significant effect. ACh (1-1000 μM ) caused graded relaxation in RA with ⁺E, these effects being markedly antagonized by L -NOARG (100 μM ), methylene blue (10 μM ) and partially by apamin (0.1 μM ), but not by indomethacin (3 μM ), glibenclamide (1 μM ) or propranolol (1 μM ). The Catuama extract (1-3000 μg/mL) produces partial relaxations in rings of RMA (mean EC₅₀ of 1073 μg7/ml and E_max of 56 % ± 13 %), an effect which was antagonized by L -NOARG (100 μM ). In RPA (⁺E) the extract produces partial relaxation followed by contraction (E_max 28 % ± 6 %), an effect which was abolished by L -NOARG (100 μM ) or methylene blue (10 μM ). The extract caused graded relaxation in rings of GPPA and GPMA with mean EC₅₀ values of 60 μg/mL and 1148 μg/mL and E_max 96% ± 2% and 88% ± 12%, respectively. L -NOARG (100 μM ) blocked the Catuama extract vasorelaxation in GPPA and only partially in GPMA, but markedly antagonized the vasorelaxations caused by ACh in both GPPA andRMA. The HE Paullinea cupana, Zinziber officinalis and Trichilia catigua (1-3000 μg/mL) caused a graded vasorelaxant effect ⁺E of RA with a mean EC₅₀ of 22, 55 and 1793 μg/mL and E_max 100%, 86% ± 7% 70% ± 2%, respectively. In addition the HE of P. cupana also caused graded relaxation in ⁻E of RA with EC₅₀ and E_max of 233 μg/mL and 100%, respectively, while T. catigua and Z. officinalis produced partial relaxation in RA ⁺E. In contrast the HE of Ptychopetalum olacoides caused little contraction (46% ± 14%). These results demonstrate that the medicinal herb Catuama produces significant vasorelaxation responses in vessels from different animal species, and show that its effects are in great part dependent on the release of NO or NO-derived substances. Our results also demonstrate that the vasorelaxant action of the product Catuama seems to be due to the action of the active principles present mainly in P. cupana; T. catigua and, to a lesser extent, in Z. officinalis. Such results may contribute to the explanation of its beneficial effect of Catuama herbal medicine in the management of cardiovascular disturbances. © 1997 John Wiley & Sons, Ltd.     

Different Effects of Some Isoquinoline Alkaloids from Argemone mexicana on Electrically Induced Contractions of Isolated Guinea-pig Ileum

The present study examines the effects of the extracts [petroleum ether, CHCl₃, CHCl₃/MeOH (9:1) and MeOH], partially purified fractions and pure compounds from Argemone mexicana on the electrically induced contractions of the isolated guinea-pig ileum (E.C.I.). The results of the experiments indicate that CHCl₃/MeOH (9:1) and MeOH extracts, tested at a concentration of 400, 200 and 100 μg/mL, dose-dependently reduced the guinea-pig ileum contractions, whereas the petroleum ether and CHCl₃ extracts did not affect it. Furthermore, the partially purified fractions II–V from the MeOH extract, each tested at concentrations of 200, 100 and 50 μg/mL also inhibited E.C.I. Finally the pure compounds 1–2 (5×10⁻⁶–1×10⁻⁵–5×10⁻⁵ M ) isolated and purified from the above fractions significantly reduced, in a dose dependent manner, the electrical contractions of the ileum, whereas compound 3 (5×10⁻⁶–1×10⁻⁵×10⁻⁵ M ) increased them. Since the active compounds 1–3 were respectively identified as protopine, allocryptopine and berberine by NMR, the observed effects could be related mainly to these compounds. © 1997 by John Wiley & Sons, Ltd.     

In vitro pharmacological evaluation of the dichloromethanol extract from Schinus molle l.

The pharmacological activity of the dichloromethanol extract of Schinus molle L. (SM-DCM) was analysed in in vitro models. Preincubation of the isolated guinea-pig ileum or rat uterus preparations with the extract (100 μg/mL) abolished the contractile effects of histamine and serotonin respectively. At the same dose, the extract partially reduced the contractile effects of acetylcholine on the isolated rat duodenum. A 10 μg/mL dose showed an inhibitory effect on histamine and serotonin, but not on acetylcholine-induced contractions (NS). No significant effect was found with a 1 μg/mL dose. © 1998 John Wiley & Sons, Ltd.     

Tanzanian medicinal plants used traditionally for the treatment of malaria: In vivo antimalarial and in vitro cytotoxic activities

Seventeen fractions of extracts obtained from 11 Tanzanian medicinal plants, which had previously been shown to possess a high antimalarial activity in vitro were submitted to the 4-day suppressive test in Plasmodium berghei-infected mice, and were investigated for cytotoxic activity in human carcinoma cell lines in vitro. Several fractions administered orally to the mice (500 mg/kg body weight/day) produced a significant reduction of parasitaemia. The most effective plant fractions investigated were those of the root and stem bark of Maytenus senegalensis (90% and 63% suppression of parasitaemia, respectively) and of the roots of Cissampelos mucronata (59% suppression). Highest cytotoxic activities were found with all fractions of Maytenus senegalensis (IC₅₀ 1 μg/mL) and with the PE fraction of the roots of Salacia madagascariensis (median IC₅₀=1.2 μg/mL for HT 29 and 2.3 μg/mL for KB).     

Antiviral activity of chilean medicinal plant extracts

Chilean flora is a potential source of bioactive compounds, including some with antiviral activity. Ninety aqueous and hydroaloholic extracts from 36 native and introduced plant species were screened for antiviral activity on herpes (HSV-1 and HSV-2) and HIV viruses. Furthermore, the samples were assayed for antimicrobial effect on pathogenic bacteria and a yeast. Plants were selected according to their indication of use for treating symptomatology of possible viral aetiology in Chilean folk medicine. The hydroaloholic extracts of Cassia stipulacea and Escallonia illintia exhibited detectable antiviral effects towards HSV-1 with IC₅₀ values of 80 and 40 μg crude extract/mL, respectively. Samples belonging to Aristotelia chilensis (IC₅₀ of 40 μg/mL), Drymis winteri (IC₅₀ values of 35 and 80μg/mL), Elytropus chilensis and Luma apiculata, with an IC₅₀ value of 100 μg/mL showed activity against HSV-2. None of the extracts showed activity against HIV at extract concentrations which were nontoxic for cells.     

The Immunosuppressive Effects of Globularia alypum Extracts

Responder lymphocytes were cultured with an equal number of irradiated stimulator lymphocytes from another donor for 6 days in RPMI 1640 (a modified Mc Coh's 5 A Medium). After 48 h incubation with PMA (phorbol 12-myristate), PHA (phytohaematogglutin) and 120 h with MLR (mixed lymphocytes reaction), the cells were labelled with ³H-thymidine. Cells were harvested in a scintillation counter Globularia alypum L. extracts were dissolved in HPLC quality ethanol or water and diluted in RPMI to concentrations ranging from 0.156–10 μg/mL. Extract solutions were added immediately after cell stimulation in the cell walls. Cyclosporin A was used as a control. Both the water and ethanol extracts of Globularia alypum L. demonstrated a dose response effect in all three systems of MLR, PHA and PMA with no statistical difference in water or ethanol extracts. The IC₅₀ were: PHA 1.14 μg/mL, PMA 1.05 μg/mL and MLR 2.06 μg/mL. The PHA and MLR IC₅₀ are approximately double the IC₅₀ for cyclosporin A (0.5 μg/mL). The effects of Glubularia alypum L. in PMA stimulated lymphocytes suggests it may suppress T cell function through a pathway that cyclosporin A does not effect.     

Effects of the essential oil of Croton zehntneri,and its constituent estragole on intestinal smooth muscle

The effects on isolated guinea-pig ileum of the essential oil of Croton zehntneri (CZEO) and of its main constituent estragole (57% of CZEO by weight) were studied. CZEO and estragole (0.1–100 μg/mL) decreased the tonus in 56% and 61.5%, respectively, of the muscles. At concentrations above 10 μg/mL, they induced spontaneous rhythmic movements of small amplitude (less than 11% of the potassium contraction peak to peak). At concentrations from 1 to 100 μg/mL and with similar potencies, these agents blocked the contractions induced by acetylcholine, histamine and 50 mM K⁺ and caused relaxation of already established potassium contractures. Tested separately, CZEO, estragole and anethole (28% of CZEO by weight) blocked the contraction induced by Ca⁺⁺ in the presence of 50 mM K⁺, but CZEO was more potent than estragole or anethole in blocking the Ca⁺⁺-induced contractions than those induced by K⁺. With large increases in the agonist concentration, the action of the oils on the contractions induced by Ca⁺⁺ was reversible; however, their effect on contractions induced by histamine or ACh was not. The data show that the essential oil of Croton zehntneri has an effect on intestinal smooth muscle that is predominantly antispasmodic, and attributable in part to the effect of estragole, a major constituent. © 1997 John Wiley & Sons, Ltd.     

Antioxidant activity of Osbeckia aspera

Plants of the Osbeckia family have been shown to possess hepatoprotective properties, which could be due to the presence of antioxidant compounds. The plant extract was shown to inhibit significantly in a dose-dependent manner, the activities of the DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical (EC₅₀ of 27.5 μg/mL), xanthine oxidase (EC₅₀ of 1.16 mg/mL) and demonstrate a scavenging effect on hydroxyl radical mediated damage to deoxyribose (EC₅₀ of 140 μg/mL). The plant extract possessed some prooxidant activity from the effect on bleomycin-induced DNA damage, but this was less than that shown by comparable concentrations of (+)-catechin or silymarin. © 1998 John Wiley & Sons, Ltd.     

Extracts of Bolivian plants,Copaifera reticulata and Heisteria pallida inhibit in vitro free radical-mediated DNA damage

The presence of different extracts of antiinflammatory plants Copaifera reticulata and Heisteria pallida in a reaction medium containing calf thymus DNA in a free radical generating system protected DNA against oxidative damage in terms of deoxyribose oxidation. The highest antioxidant activity was obtained using the methanol extract of C. reticulata (IC₅₀=3 μg/mL), followed by the aqueous extracts of H. pallida (IC₅₀=257 μg/mL) and C. reticulata (IC₅₀=380 μg/mL). Both dichloromethane extracts and the methanol extract of H. pallida showed a decreased antioxidant activity at higher concentrations. These results suggest that these extracts are capable of suppressing the in vitro oxidative degradation of DNA. © 1997 John Wiley & Sons, Ltd.     

Evaluation of pharmacological activity of a crude hydroalcoholic extract from Jatropha elliptica

The pharmacological effect of the hydroalcoholic extract of Jatropha elliptica was analysed in in vivo and in vitro models. When given orally in mice, the extract showed a low acute toxicity (LD₅₀ 5 g/kg). In a dose of 0.5 or 1 g/kg p.o. the extract did not interfere with diuresis in the rat, but was found to be effective in blocking rat paw oedema induced by carrageenan and partially, serotonin-induced oedema. In the same dose, the extract failed to inhibit rat paw oedema induced by dextran and the increase of rat cutaneous vascular permeability caused by Bothrops Jararaca venom, dextran, histamine, PAF-acether and serotonin. Pre-incubation of the isolated rat uterus and guinea-pig ileum with the extract (0.2–0.8 mg/mL), produced a concentration-related and non-competitive inhibition of contractions induced by acetylcholine and bradykinin. However, the extract was about 2-fold more potent in inhibiting the contraction of both agonists in guinea-pig ileum than in rat uterine muscle. In rat aorta, the extract (50–100 μg/mL) caused a concentration-dependent inhibition of noradrenaline-evoked contractions, being about 5-fold more potent when compared to the IC₅₀ values obtained in rat uterus.     

Compounds with tyrosinase inhibition, elastase inhibition and DPPH radical scavenging activities from the branches of Distylium racemosum Sieb. et Zucc

Twenty compounds were isolated from the ethanol extract of Distylium racemosum branches and their inhibitory activities on tyrosinase, elastase and free radicals evaluated. The isolated compounds were identified as dibenzofurans (1–4), abscisic acid (5), 6′‐O‐galloylsalidroside (6), catechin derivatives (7–11), gallic acid derivatives (12–14), tyrosol (15), flavonoids (16–18), lupeol (19) and 1,2,3,6‐tetragalloylglucose (20). For study of tyrosinase inhibition activities, when compared with arbutin (IC₅₀ 48.8 μg/mL), four compounds (8, 11, 13, 17) showed higher activities, with IC₅₀ values of 4.8, 30.2, 40.5 and 37.7 μg/mL, respectively. For the elastase inhibition test, dibenzofuran 1 showed greater activity than the positive control, oleanolic acid (IC₅₀ 9.7 μg/mL), with an IC₅₀ of 7.7 μg/mL. In the studies on DPPH radical scavenging activities, five compounds (11, 12, 13, 14, 15) showed higher activities than ascorbic acid (IC₅₀ 5.0 μg/mL), with IC₅₀ values of 4.6, 3.9, 2.9, 3.8 and 4.7 μg/mL, respectively. Copyright © 2011 John Wiley & Sons, Ltd.     

Antiprotozoal activity of Jatrogrossidione from Jatropha grossidentata and Jatrophone from Jatropha isabellii

The activity of jatrogrossidione, the main diterpene of Jatropha grossidentata and jatrophone from Jatropha isabellii was determined against Leishmania and Trypanosoma cruzi strains in vitro as well as against Leishmania amazonensis in vivo. Jatrogrossidione showed a strong in vitro leishmanicidal and trypanocidal activity with IC₁₀₀ of 0.75 and 1.5–5.0 μg/mL, respectively. Under similar conditions, the IC₁₀₀ of glucantime, ketoconazole and pentamidine towards Leishmania strains were >100, 50–100 and 1 μg/mL, respectively. The IC₅₀ of jatrogrossidione was <0.25 μg/mL against amastigote forms of Leishmania infecting macrophages, with toxicity at concentrations higher than 0.5 μg/mL. BALB/c mice infected with L. amazonensis strain PH 8 were treated 24 h after infection with jatrogrossidione and jatrophone for 13 consecutive days. Jatrophone at 25 mg/kg/day subcutaneously administered was significantly active ( p <0.05) against the virulent strain PH 8 of L. amazonesis ; it was more active than Glucantime at 112 mg Sb^v per kg/day. Subcutaneous administration of jatrophone, however, proved to be too toxic under our assay conditions. Assays of single local treatment on the footpad infection 2 weeks after inoculation of L. amazonensis indicated that jatrogrossidione and jatrophone were inactive at the selected doses.