ABSTRACT
This literature-based review synthesizes the available scientific information about steviol glycosides as natural sweeteners and molecules with therapeutic potential. In addition, it discusses the safety concerns regarding human consumption. Steviol glycosides exhibit a superior sweetener proficiency to that of sucrose and are noncaloric, noncariogenic, and nonfermentative. Scientific evidence encourages stevioside and rebaudioside A as sweetener alternatives to sucrose and supports their use based on their absences of harmful effects on human health. Moreover, these active compounds isolated from Stevia rebaudiana possess interesting medicinal activities, including antidiabetic, antihypertensive, anti-inflammatory, antioxidant, anticancer, and antidiarrheal activity. The described bioactivities of steviol glycosides deserve special attention based on their dose dependence and specific pathological situations. Further clinical research is needed to understand underlying mechanisms of action, therapeutic indexes, and pharmacological applications.
Subject(s)
Diterpenes, Kaurane , Stevia , Humans , Glucosides/pharmacology , Diterpenes, Kaurane/pharmacology , Sweetening Agents/pharmacology , Sucrose , Glycosides/pharmacologyABSTRACT
The pharmacological attributes of turmeric have been extensively described and frequently related to the action of curcuminoids. However, there is also scientific evidence of the contribution of turmeric oil. Since the oil does not contain curcuminoids in its composition, it is crucial to better understand the therapeutic role of other constituents in turmeric. The present review discusses the pharmacokinetics of turmeric oil, pointing to the potential application of its active molecules as therapeutic compounds. In addition, the bioactivities of turmeric oil and its safety in preclinical and clinical studies were revised. This literature-based research intends to provide an updated overview to promote further research on turmeric oil and its constituents.
Subject(s)
Curcuma , Curcumin , Curcumin/pharmacology , Diarylheptanoids , Plant Extracts/pharmacologyABSTRACT
In a previous study, we uncovered the anticonvulsant properties of turmeric oil and its sesquiterpenoids (ar-turmerone, α-, ß-turmerone and α-atlantone) in both zebrafish and mouse models of chemically-induced seizures using pentylenetetrazole (PTZ). In this follow-up study, we aimed at evaluating the anticonvulsant activity of ar-turmerone further. A more in-depth anticonvulsant evaluation of ar-turmerone was therefore carried out in the i.v. PTZ and 6-Hz mouse models. The potential toxic effects of ar-turmerone were evaluated using the beam walking test to assess mouse motor function and balance. In addition, determination of the concentration-time profile of ar-turmerone was carried out for a more extended evaluation of its bioavailability in the mouse brain. Ar-turmerone displayed anticonvulsant properties in both acute seizure models in mice and modulated the expression patterns of two seizure-related genes (c-fos and brain-derived neurotrophic factor [bdnf]) in zebrafish. Importantly, no effects on motor function and balance were observed in mice after treatment with ar-turmerone even after administering a dose 500-fold higher than the effective dose in the 6-Hz model. In addition, quantification of its concentration in mouse brains revealed rapid absorption after i.p. administration, capacity to cross the BBB and long-term brain residence. Hence, our results provide additional information on the anticonvulsant properties of ar-turmerone and support further evaluation towards elucidating its mechanism of action, bioavailability, toxicity and potential clinical application.
Subject(s)
Anticonvulsants/pharmacokinetics , Blood-Brain Barrier , Brain/drug effects , Ketones/pharmacokinetics , Seizures/drug therapy , Sesquiterpenes/pharmacokinetics , Animals , Anticonvulsants/pharmacology , Behavior, Animal/drug effects , Brain/metabolism , Brain/physiopathology , Brain-Derived Neurotrophic Factor/genetics , Brain-Derived Neurotrophic Factor/metabolism , Disease Models, Animal , Gene Expression Regulation/drug effects , Injections, Intraperitoneal , Ketones/pharmacology , Male , Mice , Mice, Inbred C57BL , Motor Activity/drug effects , Pentylenetetrazole , Postural Balance/drug effects , Proto-Oncogene Proteins c-fos/genetics , Proto-Oncogene Proteins c-fos/metabolism , Seizures/chemically induced , Seizures/metabolism , Seizures/physiopathology , Sesquiterpenes/pharmacology , ZebrafishABSTRACT
Turmeric, obtained from the rhizomes of Curcuma longa, is used in South Asia as a traditional medicine for the treatment of epilepsy. To date, in vivo studies on the anticonvulsant activity of turmeric have focused on its principal curcuminoid, curcumin. However, poor absorption and rapid metabolism have limited the therapeutic application of curcumin in humans. To explore the therapeutic potential of turmeric for epilepsy further, we analyzed its anticonvulsant activity in a larval zebrafish seizure assay. Initial experiments revealed that the anticonvulsant activity of turmeric in zebrafish larvae cannot be explained solely by the effects of curcumin. Zebrafish bioassay-guided fractionation of turmeric identified bisabolene sesquiterpenoids as additional anticonvulsants that inhibit PTZ-induced seizures in both zebrafish and mice. Here, we present the first report of the anticonvulsant properties of bisabolene sesquiterpenoids and provide evidence which warrants further investigation toward the mechanistic understanding of their neuromodulatory activity.
