Linalool is a monoterpene often found as a major component of essential oils obtained from aromat... more Linalool is a monoterpene often found as a major component of essential oils obtained from aromatic plant species, many of which are used in traditional medical systems as hypno-sedatives. Psychopharmacological evaluations of linalool (i.p. and i.c.v.) revealed marked sedative and anticonvulsant central effects in various mouse models. Considering this profile and alleged effects of inhaled lavender essential oil, the purpose of this study was to examine the sedative effects of inhaled linalool in mice. Mice were placed in an inhalation chamber during 60 min, in an atmosphere saturated with 1% or 3% linalool. Immediately after inhalation, animals were evaluated regarding locomotion, barbiturate-induced sleeping time, body temperature and motor coordination (rota-rod test). The 1% and 3% linalool increased (po0.01) pentobarbital sleeping time and reduced (po0.01) body temperature. The 3% linalool decreased (po0.01) locomotion. Motor coordination was not affected. Hence, linalool inhaled for 1 h seems to induce sedation without significant impairment in motor abilities, a side effect shared by most psycholeptic drugs.
Antipsychotic-like profile of alstonine. PHARMACOL BIOCHEM BEHAV 60 (1) 133–141, 1998.—Although r... more Antipsychotic-like profile of alstonine. PHARMACOL BIOCHEM BEHAV 60 (1) 133–141, 1998.—Although recently developed drugs have brought significant improvement , the treatment of psychotic disorders still presents serious drawbacks. Because inherent complexity and lack of satisfactory understanding of the underlying pathophysiology impose limits for rational drug design, resourceful approaches in the search for antipsychotics are pertinent. This article reports pharmacological properties of alstonine, a heteroyohim-bine-type alkaloid, which exhibited an antipsychotic-like profile, inhibiting amphetamine-induced lethality, apomorphine-induced stereotypy, and potentiating barbiturate-induced sleeping time. Atypical features of alstonine were the prevention of haloperidol-induced catalepsy and lack of direct interaction with D 1 , D 2 and 5-HT 2A receptors, classically linked to antipsy-chotic mechanism of action.
Page 1. Revista Brasileira de Farmacognosia 2002 Relegar a abordagem complexa em detrimento da ab... more Page 1. Revista Brasileira de Farmacognosia 2002 Relegar a abordagem complexa em detrimento da abordagem reducionista prevalecente e tratar assimetricamente o conhecimento popular e científico envolve um grande risco. ...
Nootropic, antioxidant, and neuroprotective properties have been shown in a standardized ethanol ... more Nootropic, antioxidant, and neuroprotective properties have been shown in a standardized ethanol extract of Ptychopetalum olacoides (POEE), a medicinal plant traditionally used by the Amazonian elderly population. It has been revealed that POEE mechanisms of action include anticholinesterase effects, and involve beta-adrenergic and dopamine D(1) receptors. The purpose of this study was to verify the role of serotonin receptors in the promnesic effects of this standardized extract. The step-down task in mice and selective serotonin antagonists were used. The study reveals that POEE promnesic effects on short-term (acquisition, consolidation and retrieval) and long-term (retrieval) declarative aversive memories are increased by 5HT(2A) (but not 5HT(1A)) serotonin antagonists (spiperone and pindolol, respectively). The observed synergism between POEE and spiperone can be interpreted as the combined effects of two subeffective doses of two 5HT antagonists, or the known synergism between an acetylcholinesterase inhibitor (POEE) and a 5HT antagonist. In conclusion it is suggested that 5HT(2A) serotonin receptors are relevant for the promnesic effects of this extract, adding to its multiple mechanisms of action.
Traditional remedies prepared from Ptychopetalum olacoides (PO) are used throughout the Amazon to... more Traditional remedies prepared from Ptychopetalum olacoides (PO) are used throughout the Amazon to alleviate age-related conditions. These formulas are mainly used by elders, and alleged effects may be related to the anticholinesterase properties identified in a standardized ethanol extract of this species [P. olacoides standardized ethanol extract (POEE)]. To further characterize the potential of this extract for developing drugs useful to treat cognitive deficits, the effects of POEE on scopolamine (scop)- and MK801-induced amnesias (acquisition, consolidation, and retrieval) in mice were investigated. Scop (3.0 mg/kg, ip) significantly impaired memory (all three phases) in the step-down inhibitory avoidance protocol. As expected, MK801 (0.1 mg/kg, ip) was amnesic regarding acquisition and consolidation, but not retrieval. POEE (100 mg/kg, ip) reversed the scop-induced impairment in all three phases of long-term and short memories, whereas only the memory consolidation deficit was reversed with MK801-induced amnesia. This study complements previously reported promnesic properties of this plant extract and suggests that POEE may be further developed for treating conditions associated with cognitive deficits, especially those linked with cholinergic malfunction.
To further understand the mechanism of analgesic activity and structural requirements of pyrrolid... more To further understand the mechanism of analgesic activity and structural requirements of pyrrolidinoindoline alkaloids identified in Psychotria colorata, we here report the analgesic activity of the trimer hodgkinsine on thermal and chemical models of analgesia. Results show that hodgkinsine produces a dose-dependent naloxone reversible analgesic effect in thermal models of nociception, suggesting that activation of opioid receptors participates in hodgkinsine's mode of action. Hodgkinsine shows a potent dose-dependent analgesic activity against capsaicin-induced pain, indicating the participation of NMDA receptors in hodgkinsine-induced analgesia. Such a dual mechanism of action may be of interest for developing innovative analgesics.
trans-Dehydrocrotonin (DHC), the major diterpene isolated from Croton cajucara Benth, was assayed... more trans-Dehydrocrotonin (DHC), the major diterpene isolated from Croton cajucara Benth, was assayed for antiulcerogenic activity in four induced gastric ulcer models in the rat. At an oral dose of 100 mg/kg DHC showed a significant antiulcerogenic effect on ulcers induced by hypothermic restraint stress, ethanol, and pylorus ligature. No significant changes in indomethacin-induced gastric lesions or modifications in gastric parameters such as wall mucus, secretion rate, pH, and total acid content were found after DHC treatment. The acute toxicological effects of DHC were assessed in mice. The LD50 values were 876 mg/kg and 47.2 mg/kg for oral and intraperitoneal administrations, respectively. The cytotoxicity of DHC was also studied. A dose-dependent inhibition of cell viability was observed in V-79 fibroblast cell cultures with an IC50 of 240 microM. The high yields of DHC obtained from dried C. cajucara barks as well as its good antiulcerogenic activity and low toxicity support the pharmacological study of this compound as a potential new antiulcerogenic drug.
The anti-inflammatory and antinociceptive effects of trans-dehydrocrotonin, isolated from the bar... more The anti-inflammatory and antinociceptive effects of trans-dehydrocrotonin, isolated from the bark of Croton cajucara (Euphorbiaceae), were investigated using several animal models. The trans-dehydrocrotonin produced a significant inhibition of carrageenin-induced paw edema and cotton pellet granuloma in rats. It also inhibited the writhings in mice induced by acetic acid, but did not show a significant effect in the hot-plate test in mice. The LD50 of t-DCTN was 555.0 mg/kg (p.o.) for mice.
Linalool is a monoterpene often found as a major component of essential oils obtained from aromat... more Linalool is a monoterpene often found as a major component of essential oils obtained from aromatic plant species, many of which are used in traditional medical systems as hypno-sedatives. Psychopharmacological evaluations of linalool (i.p. and i.c.v.) revealed marked sedative and anticonvulsant central effects in various mouse models. Considering this profile and alleged effects of inhaled lavender essential oil, the purpose of this study was to examine the sedative effects of inhaled linalool in mice. Mice were placed in an inhalation chamber during 60 min, in an atmosphere saturated with 1% or 3% linalool. Immediately after inhalation, animals were evaluated regarding locomotion, barbiturate-induced sleeping time, body temperature and motor coordination (rota-rod test). The 1% and 3% linalool increased (po0.01) pentobarbital sleeping time and reduced (po0.01) body temperature. The 3% linalool decreased (po0.01) locomotion. Motor coordination was not affected. Hence, linalool inhaled for 1 h seems to induce sedation without significant impairment in motor abilities, a side effect shared by most psycholeptic drugs.
Antipsychotic-like profile of alstonine. PHARMACOL BIOCHEM BEHAV 60 (1) 133–141, 1998.—Although r... more Antipsychotic-like profile of alstonine. PHARMACOL BIOCHEM BEHAV 60 (1) 133–141, 1998.—Although recently developed drugs have brought significant improvement , the treatment of psychotic disorders still presents serious drawbacks. Because inherent complexity and lack of satisfactory understanding of the underlying pathophysiology impose limits for rational drug design, resourceful approaches in the search for antipsychotics are pertinent. This article reports pharmacological properties of alstonine, a heteroyohim-bine-type alkaloid, which exhibited an antipsychotic-like profile, inhibiting amphetamine-induced lethality, apomorphine-induced stereotypy, and potentiating barbiturate-induced sleeping time. Atypical features of alstonine were the prevention of haloperidol-induced catalepsy and lack of direct interaction with D 1 , D 2 and 5-HT 2A receptors, classically linked to antipsy-chotic mechanism of action.
Page 1. Revista Brasileira de Farmacognosia 2002 Relegar a abordagem complexa em detrimento da ab... more Page 1. Revista Brasileira de Farmacognosia 2002 Relegar a abordagem complexa em detrimento da abordagem reducionista prevalecente e tratar assimetricamente o conhecimento popular e científico envolve um grande risco. ...
Nootropic, antioxidant, and neuroprotective properties have been shown in a standardized ethanol ... more Nootropic, antioxidant, and neuroprotective properties have been shown in a standardized ethanol extract of Ptychopetalum olacoides (POEE), a medicinal plant traditionally used by the Amazonian elderly population. It has been revealed that POEE mechanisms of action include anticholinesterase effects, and involve beta-adrenergic and dopamine D(1) receptors. The purpose of this study was to verify the role of serotonin receptors in the promnesic effects of this standardized extract. The step-down task in mice and selective serotonin antagonists were used. The study reveals that POEE promnesic effects on short-term (acquisition, consolidation and retrieval) and long-term (retrieval) declarative aversive memories are increased by 5HT(2A) (but not 5HT(1A)) serotonin antagonists (spiperone and pindolol, respectively). The observed synergism between POEE and spiperone can be interpreted as the combined effects of two subeffective doses of two 5HT antagonists, or the known synergism between an acetylcholinesterase inhibitor (POEE) and a 5HT antagonist. In conclusion it is suggested that 5HT(2A) serotonin receptors are relevant for the promnesic effects of this extract, adding to its multiple mechanisms of action.
Traditional remedies prepared from Ptychopetalum olacoides (PO) are used throughout the Amazon to... more Traditional remedies prepared from Ptychopetalum olacoides (PO) are used throughout the Amazon to alleviate age-related conditions. These formulas are mainly used by elders, and alleged effects may be related to the anticholinesterase properties identified in a standardized ethanol extract of this species [P. olacoides standardized ethanol extract (POEE)]. To further characterize the potential of this extract for developing drugs useful to treat cognitive deficits, the effects of POEE on scopolamine (scop)- and MK801-induced amnesias (acquisition, consolidation, and retrieval) in mice were investigated. Scop (3.0 mg/kg, ip) significantly impaired memory (all three phases) in the step-down inhibitory avoidance protocol. As expected, MK801 (0.1 mg/kg, ip) was amnesic regarding acquisition and consolidation, but not retrieval. POEE (100 mg/kg, ip) reversed the scop-induced impairment in all three phases of long-term and short memories, whereas only the memory consolidation deficit was reversed with MK801-induced amnesia. This study complements previously reported promnesic properties of this plant extract and suggests that POEE may be further developed for treating conditions associated with cognitive deficits, especially those linked with cholinergic malfunction.
To further understand the mechanism of analgesic activity and structural requirements of pyrrolid... more To further understand the mechanism of analgesic activity and structural requirements of pyrrolidinoindoline alkaloids identified in Psychotria colorata, we here report the analgesic activity of the trimer hodgkinsine on thermal and chemical models of analgesia. Results show that hodgkinsine produces a dose-dependent naloxone reversible analgesic effect in thermal models of nociception, suggesting that activation of opioid receptors participates in hodgkinsine's mode of action. Hodgkinsine shows a potent dose-dependent analgesic activity against capsaicin-induced pain, indicating the participation of NMDA receptors in hodgkinsine-induced analgesia. Such a dual mechanism of action may be of interest for developing innovative analgesics.
trans-Dehydrocrotonin (DHC), the major diterpene isolated from Croton cajucara Benth, was assayed... more trans-Dehydrocrotonin (DHC), the major diterpene isolated from Croton cajucara Benth, was assayed for antiulcerogenic activity in four induced gastric ulcer models in the rat. At an oral dose of 100 mg/kg DHC showed a significant antiulcerogenic effect on ulcers induced by hypothermic restraint stress, ethanol, and pylorus ligature. No significant changes in indomethacin-induced gastric lesions or modifications in gastric parameters such as wall mucus, secretion rate, pH, and total acid content were found after DHC treatment. The acute toxicological effects of DHC were assessed in mice. The LD50 values were 876 mg/kg and 47.2 mg/kg for oral and intraperitoneal administrations, respectively. The cytotoxicity of DHC was also studied. A dose-dependent inhibition of cell viability was observed in V-79 fibroblast cell cultures with an IC50 of 240 microM. The high yields of DHC obtained from dried C. cajucara barks as well as its good antiulcerogenic activity and low toxicity support the pharmacological study of this compound as a potential new antiulcerogenic drug.
The anti-inflammatory and antinociceptive effects of trans-dehydrocrotonin, isolated from the bar... more The anti-inflammatory and antinociceptive effects of trans-dehydrocrotonin, isolated from the bark of Croton cajucara (Euphorbiaceae), were investigated using several animal models. The trans-dehydrocrotonin produced a significant inhibition of carrageenin-induced paw edema and cotton pellet granuloma in rats. It also inhibited the writhings in mice induced by acetic acid, but did not show a significant effect in the hot-plate test in mice. The LD50 of t-DCTN was 555.0 mg/kg (p.o.) for mice.
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