Salvia divinorum and salvinorin A: an update on pharmacology and analytical methodology

Salvia divinorum L. (Lamiaceae) has been used for centuries by the Mazatecan culture and has gained popularity as a recreational drug in recent years. Its potent hallucinogenic effects seen in case reports has triggered research and led to the discovery of the first highly selective non-nitrogenous kappa opioid receptor agonist salvinorin A. This review critically evaluates the reported pharmacological and toxicological properties of S. divinorum and one of its major compounds salvinorin A, its pharmacokinetic profile, and the analytical methods developed so far for its detection and quantification. Recent research puts a strong emphasis on salvinorin A , which has been shown to be a selective opioid antagonist and is believed to have further beneficial properties , rather than the leaf extract of S. divinorum. Currently animal studies show a rapid onset of action and short distribution and elimination half-lives as well as a lack of evidence of short- or long-term toxicity. Salvinorin A seems to be the most promising approach to new treatment options for a variety of CNS illnesses. However, many further investigations are necessary to fully understand and elucidate the various medicinal properties of the plant itself and to provide the legislative authorities with enough information to cast judgement on S. divinorum.     

Neuropharmacology of the naturally occurring kappa-opioid hallucinogen salvinorin A

Salvia divinorum is a perennial sage native to Oaxaca, Mexico, that has been used traditionally in divination rituals and as a treatment for the "semimagical" disease panzón de borrego. Because of the intense "out-of-body" experiences reported after inhalation of the pyrolized smoke, S. divinorum has been gaining popularity as a recreational hallucinogen, and the United States and several other countries have regulated its use. Early studies isolated the neoclerodane diterpene salvinorin A as the principal psychoactive constituent responsible for these hallucinogenic effects. Since the finding that salvinorin A exerts its potent psychotropic actions through the activation of KOP receptors, there has been much interest in elucidating the underlying mechanisms behind its effects. These effects are particularly remarkable, because 1) salvinorin A is the first reported non-nitrogenous opioid receptor agonist, and 2) its effects are not mediated by the 5-HT(2A) receptor, the classic target of hallucinogens such as lysergic acid diethylamide and mescaline. Rigorous investigation into the structural features of salvinorin A responsible for opioid receptor affinity and selectivity has produced numerous receptor probes, affinity labels, and tools for evaluating the biological processes responsible for its observed psychological effects. Salvinorin A has therapeutic potential as a treatment for pain, mood and personality disorders, substance abuse, and gastrointestinal disturbances, and suggests that nonalkaloids are potential scaffolds for drug development for aminergic G-protein coupled receptors.     

The antinociceptive effect of salvinorin A in mice

Salvia divinorum is a hallucinogenic plant used by the Mazatec Indians of Mexico for traditional spiritual ceremonies. The active constituent, salvinorin A, induces profound hallucinations, however the biological mechanism for this action is not known. Affinity-binding studies suggest that the biologic activity of salvinorin A involves the kappa-opioid receptor. The purpose of this study was to evaluate the antinociceptive effect of salvinorin A in mice. Salvinorin A and opioid receptor antagonists were administered intrathecally and the tail-flick latencies were used as a measure of antinociception. Salvinorin A increased tail-flick latencies in a dose-dependent manner (13.9-23.1 nmol) compared to control trials. Pretreatment with the kappa-opioid receptor antagonist nor-binaltorphimine attenuated the salvinorin A induced increase in tail-flick latency. In contrast, neither the mu-opioid receptor antagonist beta-funaltrexamine nor delta-opioid receptor antagonist naltrindole significantly affected the antinociceptive response of salvinorin A administration. These data support previous reports that salvinorin A represents a unique non-alkaloidal agonist for the kappa-opioid receptor.     

The detection and quantitative analysis of the psychoactive component of Salvia divinorum, salvinorin A, in human biological fluids using liquid chromatography-mass spectrometry

Salvia divinorum, a member of the mint plant family, has hallucinogenic properties that have become increasingly sought after by recreational drug users. The main psychoactive component, salvinorin A, has potency comparable to lysergic acid diethylamide. Though still legal to possess in most of the United States and much of Europe, little is known regarding the compound's long-term health effects, addiction liability, and pharmacokinetics. Limited data are available in the scientific literature, and few analytical methods are published for the detection in human biological fluids. These factors contribute to the unfamiliarity of the compound and complicate the method development process necessary to accommodate special requested testing for salvinorin A. A sensitive analytical method for the detection and quantitation of salvinorin A in human biological fluids was developed and validated to resolve analytical shortcomings. The method utilizes a solid-phase extraction technique coupled with liquid chromatography-electrospray ionization mass spectrometry operated in selected ion monitoring mode. The assay has a linear range of 5.0-100 ng/mL with a correlation coefficient of 0.997. The limit of detection and limit of quantitation were experimentally determined as 2.5 and 5.0 ng/mL, respectively. The method has been applied to blood and urine samples successfully and can be used to detect the presence of salvinorin A in forensic testing.     

Quantitative determination of salvinorin A,a natural hallucinogen with abuse liability,in Internet-available Salvia divinorum and endemic species of Salvia in Taiwan

In recent years, recreational use of Salvia divinorum (Lamiaceae), a herbal drug that contains a hallucinogenic ingredient, salvinorin A, has become a new phenomenon among young drug users. In Taiwan, as in many other countries, dry leaves of S. divinorum and its related concentrated extract products are available via the Internet. Besides S. divinorum, there are many endemic Salvia species whose salvinorin A content is yet unknown. To understand the abuse liability of these products, the aim of this study was to assess the concentration of salvinorin A in endemic Salvia species and Internet-available salvinorin A-related products. Samples of S. divinorum were purchased via the Internet and samples of eight endemic species of Salvia were collected in Taiwan, including S. arisanensis Hayata, S. coccinea Juss. ex Murr, S. hayatana Makino ex Hayata, S. japonica Thumb. ex Murr, S. nipponica Miq. Var. formosana (Hayata) Kudo, S. scapiformis Hance, S. tashiroi Hayata. Icon. PI. Formosan, and S. keitaoensis Hayata. The content of salvinorin A was determined by high performance liquid chromatography (HPLC). Salvinorin A was extracted from the dry leaves of S. divinorum and endemic species of Salvia with methanol and analyzed on a C-18 column by isocratic elution with a mobile phase of acetonitrile–water. Salvinorin A was detected in S. divinorum, but not in the endemic Salvia species of Taiwan. Therefore, endemic species of Salvia in Taiwan may not possess hallucinogenic potential. However, the potential harm from S. divinorum available via the Internet should be thoroughly assessed in Taiwan, and control measures similar to those implemented in many other countries should be considered.     

Human psychopharmacology and dose-effects of salvinorin A, a kappa opioid agonist hallucinogen present in the plant Salvia divinorum

Salvinorin A is a potent, selective nonnitrogenous kappa opioid agonist and the known psychoactive constituent of Salvia divinorum, a member of the mint family that has been used for centuries by Mazatec shamans of Mexico for divination and spiritual healing. S. divinorum has over the last several years gained increased popularity as a recreational drug. This is a double-blind, placebo controlled study of salvinorin A in 4 psychologically and physically healthy hallucinogen-using adults. Across sessions, participants inhaled 16 ascending doses of salvinorin A and 4 intermixed placebo doses under comfortable and supportive conditions. Doses ranged from 0.375 μg/kg to 21 μg/kg. Subject-rated drug strength was assessed every 2 min for 60 min after inhalation. Orderly time- and dose-related effects were observed. Drug strength ratings peaked at 2 min (first time point) and definite subjective effects were no longer present at approximately 20 min after inhalation. Dose-related increases were observed on questionnaire measures of mystical-type experience (Mysticism Scale) and subjective effects associated with classic serotonergic (5-HT2(A)) hallucinogens (Hallucinogen Rating Scale). Salvinorin A did not significantly increase heart rate or blood pressure. Participant narratives indicated intense experiences characterized by disruptions in vestibular and interoceptive signals (e.g., change in spatial orientation, pressure on the body) and unusual and sometimes recurring themes across sessions such as revisiting childhood memories, cartoon-like imagery, and contact with entities. Under these prepared and supportive conditions, salvinorin A occasioned a unique profile of subjective effects having similarities to classic hallucinogens, including mystical-type effects.     

Authentication and ultra performance liquid chromatography (UPLC)/MS analysis of magic mint, Salvia divinorum and its related plants

Ultra performance liquid chromatography (UPLC)/mass spectrometry (MS) analysis was performed to investigate whether commercial Salvia cultivars available in the Japanese market contain salvinorin A (1), which is an hallucinogen present in magic mint (Salvia divinorum) prior to the regulation of S. divinorum by the Japanese Pharmaceutical Affairs Law. In addition, a previously reported method to authenticate S. divinorum, utilizing an amplification refractory mutation system (ARMS) was applied to the same samples to estimate the method's accuracy. As a result of the UPLC/MS analysis, it was clear that none of the tested cultivars possessed 1 while S. divinorum leaves and its processed products "concentrated salvia" contained 1 in the range from 0.19% to 0.58%. Furthermore, the ARMS method could clearly distinguish S. divinorum from the tested cultivars. In conclusion, the authentication method is considered to be useful for the practical regulation of S. divinorum due to its simplicity and accuracy.     

Analysis of the psychoactive terpenoid salvinorin A content in five Salvia divinorum herbal products

STUDY OBJECTIVE: To determine the content of the hallucinogen salvinorin A in a variety of Salvia divinorum herbal products and to compare the content with the label claims of potency and purity. DESIGN: Laboratory analysis. SETTING: University-affiliated laboratory. SAMPLES: Five herbal products containing Salvia divinorum. MEASUREMENTS AND MAIN RESULTS: The samples were purchased from the Internet and local drug paraphernalia shops ("head shops"). Highperformance liquid chromatography and thin-layer chromatography-gas chromatography-mass spectroscopy were used for the analysis. All five samples contained salvinorin A, a psychoactive compound found in Salvia divinorum; however, the salvinorin A concentrations we measured were much lower than those claimed on the product label. Vitamin E was also found in two samples and caffeine in one sample. CONCLUSION: The five salvinorin A herbal products were found to be subpotent, and three products contained adulterants. Any discrepancy between the advertised salvinorin A concentration and their actual concentration may pose a potential risk of both misuse and overdose. These concerns, and the recently reported teenage suicide that could have been related to salvia consumption, underscore the need for practitioners to become familiar with the signs and symptoms of salvia use.     

Salvinorin A fails to substitute for the discriminative stimulus effects of LSD or ketamine in Sprague-Dawley rats

Salvia divinorum is a small perennial shrub that has gained recent popularity among the drug-using subculture as a legal alternative to hallucinogens. Salvinorin A, the main active compound found in the S.divinorum plant, is an atypical hallucinogen with pharmacological selectivity at kappa opioid (KOP) receptor sites and is a unique non-nitrogenous neoclerodane diterpene which is structurally distinct from other opioid compounds. The novel structure of salvinorin A and its specific binding affinity to KOP receptors provide a unique opportunity to investigate neurochemical mechanisms of hallucination and hallucinogenic compounds. The current investigation assessed the substitution of salvinorin A in 16 male Sprague-Dawley rats trained to discriminate either the prototypical serotonergic hallucinogen, LSD (0.08 mg/kg, S.C., n = 8) or the dissociative anesthetic and glutamatergic hallucinogen, ketamine (8.0 mg/kg, I.P., n = 8) from vehicle under a FR 20 schedule of food-reinforced responding. Results indicated that neither LSD nor ketamine discrimination generalized to salvinorin A. These findings are consistent with the growing body of evidence that salvinorin A is pharmacologically distinct from other traditional hallucinogenic compounds.     

Salvinorin B derivatives, EOM-Sal B and MOM-Sal B, produce stimulus generalization in male Sprague-Dawley rats trained to discriminate salvinorin A

Salvinorin A, the main active component of Salvia divinorum, is a potent and selective κ opioid receptor agonist. Synthetic derivatives of this substance may be useful in the development of medicinal treatments for pain, mood disorders, and drug dependence. Such developments require extensive preclinical screening of these compounds. The drug discrimination assay is a valuable method for exploring potential similarities between novel compounds and known drugs of abuse with respect to their interoceptive stimulus properties, and can be used to investigate the potency of salvinorin A and its derivatives in vivo. This study used drug discrimination methods to compare two synthetic derivatives of salvinorin B, the ethoxymethyl ether (EOM-Sal B) and methoxymethyl ether (MOM-Sal B) with salvinorin A. Male Sprague-Dawley rats were trained to discriminate 2.0 mg/kg of salvinorin A from its vehicle (75% dimethylsulfoxide/25% water) in a fixed ratio 20 food-reinforced drug discrimination procedure, and were tested for stimulus generalization with EOM-Sal B and MOM-Sal B. For comparison, substitution tests were also conducted with a μ agonist, morphine, a dissociative hallucinogen, ketamine, and two serotonergic hallucinogens, D-lysergic diethylamide (LSD) and 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane. Time-course tests were also conducted with salvinorin A and EOM-Sal B. Both EOM-Sal B and MOM-Sal B substituted fully for salvinorin A and displayed greater potency than salvinorin A. EOM-Sal B was discriminated at longer postinjection intervals than salvinorin A. Morphine and 1-(2,5-dimethoxy-4-methylphenyl)-2-aminopropane failed to substitute for salvinorin A, although ketamine and LSD produced significant drug-appropriate responding. The current findings are consistent with previous reports that salvinorin A produces detectable stimulus effects that are distinct from those of other drug classes and, for the first time, establish that synthetic derivatives of this substance produce similar discriminative stimulus effects. The unexpected partial substitution with LSD and ketamine indicate that further preclinical studies of these novel κ opioid receptor agonists may be warranted.     

Legally tripping: a qualitative profile of Salvia divinorum use among young adults

During recent years, there has been increasing interest in "legal highs" among youth and young adults. Salvia divinorum is a legally available hallucinogenic plant, primarily utilized in smokable form, that produces a brief but intense hallucinogenic experience for the user. Data are presented from an ethnographic project to provide a qualitative profile of salvia use among young adults. Most users report primarily using in home settings such as apartments and houses, although a significant minority report use in environments such as parks, bars, and parties. The intense nature of the substance creates a differential subjective experience. Some describe the intensity of the hallucinogenic experience in positive ways. Others find the experience so intense that they would not continue to use the substance. With regard to the health effects of salvia, most young adults report no significant negative health effects from salvia use, although some report a mental cloudiness. Beyond their own experiences, users did not report any negative health events among peers. The lack of reports of negative effects may reinforce social norms favorable towards salvia use. Overall, young adults report a relatively low risk profile for salvia divinorum, which may be influenced, in part, by its legal status.     

Kappa opioid mediation of cannabinoid effects of the potent hallucinogen, salvinorin A, in rodents

Rationale

Salvinorin A, the primary psychoactive derivative of the hallucinogenic herb Salvia divinorum, is a potent and highly selective kappa-opioid receptor (KOR) agonist. Several recent studies, however, have suggested endocannabinoid system mediation of some of its effects.

Objectives

This study represents a systematic examination of this hypothesis.

Methods

Salvinorin A was isolated from S. divinorum and was evaluated in a battery of in vitro and in vivo procedures designed to detect cannabinoid activity, including CB₁ receptor radioligand and [³⁵S]GTPγS binding, calcium flux assay, in vivo cannabinoid screening tests, and drug discrimination.

Results

Salvinorin A did not bind to nor activate CB₁ receptors. In vivo salvinorin A produced pronounced hypolocomotion and antinociception (and to a lesser extent, hypothermia). These effects were blocked by the selective KOR antagonist, JDTic, but not by the CB₁ receptor antagonist rimonabant. Interestingly, however, rimonabant attenuated KOR activation stimulated by U69,593 in a [³⁵S]GTPγS assay. Salvinorin A did not substitute for Δ⁹-tetrahydrocannabinol (THC) in mice trained to discriminate THC.

Conclusions

These findings suggest that similarities in the pharmacological effects of salvinorin A and those of cannabinoids are mediated by its activation of KOR rather than by any direct action of salvinorin A on the endocannabinoid system. Further, the results suggest that rimonabant reversal of salvinorin A effects in previous studies may be explained in part by rimonabant attenuation of KOR activation.     

Subjective effects of Salvia divinorum

Salvia divinorum is a hallucinogenic plant native to Mexico, where the Mazatec Indians use it in divinatory rituals as a facilitator for contacting the spirits of the dead. A number of traditions surrounding the ritualistic use of Salvia are still observed. Generally the leaves are chewed for the visionary effects. Salvia has recently been embraced by Western drug cultures, where the traditional methods of ingestion are generally eschewed for the more immediately effective technique of smoking the dried leaves. This article discusses the history and indigenous cultural uses of Salvia before outlining its rediscovery in the 1960s and its subsequent introduction to the Western drug scenes (particularly Britain) since the mid 1990s. Qualitative data from 10 Salvia users were collected by means of email interviews. The participants were asked to provide as in-depth responses as possible. No time or space limit on answers was imposed. Their responses to each question are presented verbatim. The effects of Salvia appear to vary between users and seem sensitive to situational factors. Users who understand something of the ritualistic setting for traditional use would appear to have a fuller experience than those who do not.     

In vitro studies on metabolism of salvinorin A

Microbial transformation of natural products is a well established model for mammalian metabolism. Salvinorin A, a diterpenoid isolated from the hallucinogenic mint Salvia divinorum Epling & Játiva-M (Lamiaceae), is a potent non-nitrogenous κ-opioid receptor agonist. The metabolism of salvinorin A has still not yet been well established. Thirty fungal species were screened for the ability to metabolize salvinorin A. We observed that salvinorin A undergoes fast hydrolysis of the acetate group at carbon atom C2, resulting in formation of the pharmacologically inactive product, salvinorin B. Ex vivo experiments were also performed using organelle fractions isolated from rat liver and brain. Crude tissue homogenate and individual organelles show that the primary route of salvinorin A metabolism is hydrolysis to salvinorin B. No metabolic transformation of salvinorin B was observed in these studies.     

Learning and memory impairment induced by salvinorin A, the principal ingredient of Salvia divinorum, in wistar rats

The effects of salvinorin A (Salvia divinorum principal ingredient), a potent κ-opioid natural hallucinogen, on learning and memory were investigated. Wistar rats were tested in the 8-arm radial maze, for object recognition and passive avoidance tasks for spatial, episodic, and aversive memory. Attention was assessed using a latent inhibition task. Salvinorin A (80-640 μg/kg subcutaneous [sc]) did not affect short-term memory, but it impaired spatial long-term memory. Episodic and aversive memories were impaired by salvinorin A (160-640 μg/kg). Memory impairment was blocked by the selective κ-opioid receptor antagonist, nor-binaltorphimine ([nor-B]; 0.5-1 mg/kg, intraperitoneal [ip]). Salvinorin A (160 μg/kg) disrupted latent inhibition, after LiCl treatment, such as reduced sucrose intake, suggesting an attention would result in an impairment of cognitive behavior. These findings demonstrate for the first time that salvinorin A has deleterious effects on learning and memory, through a κ-opioid receptor mechanism.     

Neoclerodane diterpenes as a novel scaffold for mu opioid receptor ligands

Structural modification of salvinorin A, the active component of Salvia divinorum, has resulted in the synthesis of novel neoclerodane diterpenes with opioid receptor affinity and activity. We report in this study a nonnitrogenous neoclerodane diterpene with mu opioid receptor affinity (13) that is an agonist at mu opioid receptors. This represents the identification of a novel structural class of mu opioid receptor agonists.