Study on embryo-foetotoxicity of beta-myrcene in the rat

Myrcene-What Are the Potential Health Benefits of This Flavouring and Aroma Agent?

Myrcene (β-myrcene) is an abundant monoterpene which occurs as a major constituent in many plant species, including hops and cannabis. It is a popular flavouring and aroma agent (food additive) used in the manufacture of food and beverages. This review aims to report on the occurrence, biological and toxicological profile of β-myrcene. The main reported biological properties of β-myrcene-anxiolytic, antioxidant, anti-ageing, anti-inflammatory, analgesic properties-are discussed, with the mechanisms of activity. Here we also discuss recent data regarding the safety of β-myrcene. Overall, β-myrcene has shown promising health benefits in many animal studies. However, studies conducted in humans is lacking. In the future, there is potential for the formulation and production of non-alcoholic beers, functional foods and drinks, and cannabis extracts (low in THC) rich in β-myrcene.

RIFM fragrance ingredient safety assessment, 3,7-dimethyl-1,3,6-octatriene, CAS registry number 13877-91-3

The existing information supports the use of this material as described in this safety assessment. 3,7-Dimethyl-1,3,6-octatriene was evaluated for genotoxicity, repeated dose toxicity, developmental and reproductive toxicity, local respiratory toxicity, phototoxicity/photoallergenicity, skin sensitization, and environmental safety. Data from 3,7-dimethyl-1,3,6-octatriene and read-across analog myrcene (β-myrcene; CAS # 123-35-3) show that 3,7-dimethyl-1,3,6-octatriene is not expected to be genotoxic and provide a calculated margin of exposure (MOE) >100 for the repeated dose toxicity and developmental and reproductive toxicity endpoints. The skin sensitization endpoint was completed using the dermal sensitization threshold (DST) for non-reactive materials (900 μg/cm 2 ); exposure is below the DST. The phototoxicity/photoallergenicity endpoints were evaluated based on ultraviolet (UV) spectra; 3,7-dimethyl-1,3,6- octatriene is not expected to be phototoxic/photoallergenic. The local respiratory toxicity endpoint was evaluated using the threshold of toxicological concern (TTC) for a Cramer Class I material, and the exposure to 3,7-dimethyl-1,3,6-octatriene is below the TTC (1.4 mg/day). The environmental endpoints were evaluated; 3,7-dimethyl-1,3,6- octatriene was found not to be persistent, bioaccumulative, and toxic (PBT) as per the International Fragrance Association (IFRA) Environmental Standards, and its risk quotients, based on its current volume of use in Europe and North America (i.e., Predicted Environmental oncentration/Predicted No Effect Concentration [PEC/PNEC]), are <1.

Myrcene and terpene regulation of TRPV1

Nociceptive Transient Receptor Potential channels such as TRPV1 are targets for treating pain. Both antagonism and agonism of TRP channels can promote analgesia, through inactivation and chronic desensitization. Since plant-derived mixtures of cannabinoids and the Cannabis component myrcene have been suggested as pain therapeutics, we screened terpenes found in Cannabis for activity at TRPV1. We used inducible expression of TRPV1 to examine TRPV1-dependency of terpene-induced calcium flux responses. Terpenes contribute differentially to calcium fluxes via TRPV1 induced by Cannabis-mimetic cannabinoid/terpenoid mixtures. Myrcene dominates the TRPV1-mediated calcium responses seen with terpenoid mixtures. Myrcene-induced calcium influx is inhibited by the TRPV1 inhibitor capsazepine and Myrcene elicits TRPV1 currents in the whole-cell patch-clamp configuration. TRPV1 currents are highly sensitive to internal calcium. When Myrcene currents are evoked, they are distinct from capsaicin responses on the basis of Imax and their lack of shift to a pore-dilated state. Myrcene pre-application and residency at TRPV1 appears to negatively impact subsequent responses to TRPV1 ligands such as Cannabidiol, indicating allosteric modulation and possible competition by Myrcene. Molecular docking studies suggest a non-covalent interaction site for Myrcene in TRPV1 and identifies key residues that form partially overlapping Myrcene and Cannabidiol binding sites. We identify several non-Cannabis plant-derived sources of Myrcene and other compounds targeting nociceptive TRPs using a data mining approach focused on analgesics suggested by non-Western Traditional Medical Systems. These data establish TRPV1 as a target of Myrcene and suggest the therapeutic potential of analgesic formulations containing Myrcene.

FEMA GRAS assessment of natural flavor complexes: Citrus-derived flavoring ingredients

In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavoring ingredients. This publication is the first in a series and summarizes the evaluation of 54 Citrus-derived NFCs using the procedure outlined in Smith et al. (2005) and updated in Cohen et al. (2018) to evaluate the safety of naturally-occurring mixtures for their intended use as flavoring ingredients. The procedure relies on a complete chemical characterization of each NFC intended for commerce and organization of each NFC's chemical constituents into well-defined congeneric groups. The safety of the NFC is evaluated using the well-established and conservative threshold of toxicological concern (TTC) concept in addition to data on absorption, metabolism and toxicology of members of the congeneric groups and the NFC under evaluation. As a result of the application of the procedure, 54 natural flavor complexes derived from botanicals of the Citrus genus were affirmed as generally recognized as safe (GRAS) under their conditions of intended use as flavoring ingredients based on an evaluation of each NFC and the constituents and congeneric groups therein.

Study of the effects of beta-myrcene on rat fertility and general reproductive performance

beta-Myrcene (MYR) is a monoterpene found in the oils of a variety of aromatic plants including lemongrass, verbena, hop, bay, and others. MYR and essential oils containing this terpenoid compound are used in cosmetics, household products, and as flavoring food additives. This study was undertaken on investigate the effects of MYR on fertility and general reproductive performance in the rat. MYR (0, 100, 300 and 500 mg/kg) in peanut oil was given by gavage to male Wistar rats (15 per dose group) for 91 days prior to mating and during the mating period, as well as to females (45 per dose group) continuously for 21 days before mating, during mating and pregnancy, and throughout the period of lactation up to postnatal day 21. On day 21 of pregnancy one-third of the females of each group were submitted to cesarean section. Resorption, implantation, as well as dead and live fetuses were counted. All fetuses were examined for external malformations, weighed, and cleared and stained with Alizarin Red S for skeleton evaluation. The remaining dams were allowed to give birth to their offspring. The progeny was examined at birth and subsequently up to postnatal day 21. Mortality, weight gain and physical signs of postnatal development were evaluated. Except for an increase in liver and kidney weights, no other sign of toxicity was noted in male and female rats exposed to MYR. MYR did not affect the mating index (proportion of females impregnated by males) or the pregnancy index (ratio of pregnant to sperm-positive females). No sign of maternal toxicity and no increase in externally visible malformations were observed at any dose level. Only at the highest dose tested (500 mg/kg) did MYR induce an increase in the resorption rate and a higher frequency of fetal skeleton anomalies. No adverse effect of MYR on postnatal weight gain was noted but days of appearance of primary coat, incisor eruption and eye opening were slightly delayed in the exposed offspring. On the basis of the data presented in this paper the no-observed-adverse-effect level (NOAEL) for toxic effects on fertility and general reproductive performance can be set at 300 mg of beta-myrcene/kg body weight by the oral route.

Study of the embryofeto-toxicity of Crown-of-Thorns (Euphorbia milii) latex, a natural molluscicide

The crude latex of Crown-of-Thorns (Euphorbia milii var. hislopii) is a potent plant molluscicide and a promising alternative to the synthetic molluscicides used in schistosomiasis control. The present study was undertaken to investigate the embryofeto-toxic potential of E. milii latex. The study is part of a comprehensive safety evaluation of this plant molluscicide. Lyophilized latex (0, 125, 250 and 500 mg/kg body weight) in corn oil was given by gavage to Wistar rats (N = 100) from days 6 to 15 of pregnancy and cesarean sections were performed on day 21 of pregnancy. The numbers of implantation sites, living and dead fetuses, resorptions and corpora lutea were recorded. Fetuses were weighed, examined for external malformations, and fixed for visceral examination, or cleared and stained with Alizarin red S for skeleton evaluation. A reduction of body weight minus uterine weight at term indicated that E. milii latex was maternally toxic over the dose range tested. No latex-induced embryolethality was noted at the lowest dose (125 mg/kg) but the resorption rate was markedly increased at 250 mg/kg (62.5%) and 500 mg/kg (93.4%). A higher frequency of fetuses showing signs of delayed ossification (control: 17.4%; 125 mg/kg: 27.4% and 250 mg/kg: 62.8%; P < 0.05 vs control) indicated that fetal growth was retarded at doses > or = 125 mg latex/kg body weight. No increase in the proportion of fetuses with skeletal anomalies was observed at the lowest dose but the incidence of minor skeletal malformations was higher at 250 mg/kg body weight (control: 13.7%; 125 mg/kg: 14.8%; 250 mg/kg: 45.7%; P < 0.05 vs control). Since a higher frequency of minor malformations was noted only at very high doses of latex which are embryolethal and maternally toxic, it is reasonable to conclude that this plant molluscicide poses no teratogenic hazard or, at least, that this possibility is of a considerably low order of magnitude.

Study of the embryofoetotoxicity of alpha-terpinene in the rat

alpha-Terpinene (1-isopropyl-4-methyl-1,3-cyclohexadiene) (TER) is a monoterpene found in the essential oils of a large variety of useful plants. Despite the widespread use of plants and essential oils containing TER in folk medicine potions and cosmetics, and as a flavouring food additive, toxicity studies of this monoterpene are scarce. The present study was undertaken to provide data on the embryofoetotoxic potential of TER in the rat. TER (30, 60, 125 and 250 mg/kg body weight) in corn oil was given by gavage to female Wistar rats from day 6 to 15 of pregnancy. Caesarean sections were performed on day 21 of pregnancy. The number of implantation sites, living and dead foetuses, resorptions and corpora lutea were recorded. All foetuses were weighed, examined for externally visible malformations, numbered with a marker pen and fixed in 5% formalin solution. One-third of the foetuses of each litter, chosen at random, were evaluated for visceral anomalies by a microsectioning technique. Heart, lungs, thymus, liver, spleen and kidneys of foetuses that were microdissected were also weighed. The remaining foetuses were examined for skeletal malformations after clearing with potassium hydroxide and staining with Alizarin Red S. A reduction in body weight minus uterine weight at term indicated that the two highest doses tested [125 and 250 mg TER/kg body weight orally] were maternally toxic. No increase in the ratio of resorptions/implantations was observed over the dose range tested. The highest dose of TER (250 mg/kg body weight) reduced the ratio of pregnant/treated female. A decrease in foetal body weight and an increase in foetal kidney weights were noted at 250 mg TER/kg body weight. Signs of delayed ossification (poorly ossified and not ossified bones as well as irregular spongy bones) and a higher incidence of minor skeletal malformations were observed at doses of 60 mg/kg body weight or more. These findings indicate that the no-observed-adverse-effect level for TER-induced embryofoetotoxicity can be set at 30 mg/kg body weight by the oral route.

Peri- and postnatal developmental toxicity of beta-myrcene in the rat

beta-Myrcene (MYR) and essential oils containing this monoterpene have been widely used as scenting agents in cosmetics, detergents, soaps, and as flavouring additives in food and beverages. Recently, MYR was reported to be an analgesic substance and the active principle of lemongrass tea. Despite the importance of human exposure to MYR, its toxicological profile has not been comprehensively studied. The aim of this study was to provide data on the peri- and postnatal developmental toxicity of this terpene. MYR (0.25, 0.5, 1.0 and 1.5 g/kg) in corn oil was given by gavage to female Wistar rats from day 15 of pregnancy, parturition and throughout the period of lactation up to weaning (postnatal day 21). The progeny were examined at birth and subsequently to weaning. Mortality, weight gain and physical signs of postnatal development (ear unfolding, incisor eruption, fur development and eye opening) were evaluated. When the exposed offspring reached maturity (120 days) their reproductive capacity was assessed. No adverse effects on the offspring were seen with the lowest dose tested, but 0.5 g/kg and higher doses decreased birth weight, increased perinatal mortality and delayed the day of appearance of landmarks of postnatal development. Moreover, fertility was impaired in female offspring exposed to the two highest doses of MYR. From the data presented in this paper the no-observed-adverse-effect level for peri- and postnatal developmental toxicity could be set at 0.25 g beta-myrcene/kg body weight.