Lobelia Aerial Parts And Seed Extract
Also known as: Lobelia inflata, Lobelia pyramidalis, Lobelia chinensis, Lobelia sessilifolia, Indian tobacco, Lobelia
Overview
Lobelia aerial parts and seed extract are primarily derived from *Lobelia inflata* and related species. This botanical extract is known for its alkaloid content, notably α-lobeline, alongside essential oils, polyacetylenes, and glucosides. Traditionally, Lobelia has been used as a respiratory stimulant and expectorant, particularly for conditions like asthma and bronchitis. Its historical use also includes attempts at smoking cessation due to lobeline's partial nicotine agonist activity. While preclinical research suggests antiasthmatic, antispasmodic, emetic, expectorant, respiratory stimulant, antimicrobial, anti-inflammatory, and potential cytotoxic properties, robust human clinical trials are largely absent, limiting definitive conclusions on its efficacy and safety in humans.
Benefits
Research on Lobelia's benefits is primarily preclinical, with limited human data. Alpha-lobeline, a key alkaloid, has shown transient respiratory stimulant effects in animal models (horses, pigs, rabbits), increasing tidal volume and respiratory rate. Traditionally, it has been used for asthma and bronchitis, but controlled human trials are lacking. Lobeline's role as a partial nicotine agonist has led to its investigation for smoking cessation, though clinical trial results have been inconclusive. Essential oils from *Lobelia pyramidalis* demonstrate moderate antimicrobial activity against bacteria like *Staphylococcus aureus* in vitro (MIC around 3.12 mg/ml). Compounds from *Lobelia chinensis*, such as lobechine and polyacetylenes, exhibit in vitro anti-inflammatory effects and moderate cytotoxicity against cancer cell lines, but these are preliminary findings. Additionally, a glucoside from *Lobelia sessilifolia* showed potent α-glucosidase inhibition in vitro, suggesting potential anti-diabetic effects, though no human data supports this.
How it works
The primary mechanism of action for Lobelia is attributed to α-lobeline, its main active alkaloid. Alpha-lobeline acts as a partial agonist at nicotinic acetylcholine receptors, influencing both the central nervous system and peripheral respiratory control centers. This interaction stimulates breathing, primarily through its effects on carotid and aortic body chemoreceptors. Other constituents, such as perilla ketone found in the essential oil, may contribute to its observed antimicrobial effects. The anti-inflammatory properties seen in some Lobelia compounds, like lobechine and scoparone, are thought to be mediated by the inhibition of elastase release and superoxide anion generation. While lobeline is known to cross the blood-brain barrier, detailed human pharmacokinetic data and bioavailability are not well characterized.
Side effects
Lobelia extracts can be toxic at high doses, primarily due to the emetic and neuromuscular effects of its alkaloids. Historically used as an emetic, overdose can lead to severe symptoms. Common side effects, reported in over 5% of users, include nausea, vomiting, diarrhea, and headache. Uncommon side effects (1-5%) may involve dizziness, tremors, and an increased heart rate. In rare cases (less than 1%), severe respiratory distress, convulsions, and coma have been reported, particularly in overdose situations. Lobelia may have additive effects with other CNS stimulants or depressants and should be used with caution alongside nicotine replacement therapies due to lobeline's partial nicotine agonism. It is contraindicated in pregnancy, breastfeeding, individuals with cardiovascular disease, and those with seizure disorders. Due to toxicity risks and a lack of safety data, children and the elderly should avoid Lobelia.
Dosage
There is no established minimum effective dose for Lobelia for respiratory or other indications due to a significant lack of human clinical trials. Traditional herbal doses vary widely, and standardized extracts with quantified lobeline content are not well-defined. The maximum safe dose has not been established, and toxicity has been reported with excessive intake. Traditionally, Lobelia has been consumed as tinctures, teas, or extracts. Animal studies have explored inhalation or injection forms, but these are not applicable to human supplementation. Absorption factors and cofactors influencing bioavailability are not well studied, meaning the effectiveness may vary significantly depending on the preparation and individual factors.
FAQs
Is lobelia safe for asthma?
Animal studies suggest respiratory stimulation, but there are no human randomized controlled trials confirming its safety or efficacy for asthma. Use with extreme caution due to potential toxicity.
Can lobelia help quit smoking?
Lobeline acts as a partial nicotine agonist, which led to its investigation for smoking cessation. However, clinical evidence for its effectiveness in helping people quit smoking is inconclusive.
What are the side effects of lobelia?
Common side effects include nausea, vomiting, diarrhea, and headache. Overdose can lead to more serious issues like severe respiratory distress, convulsions, and even coma.
How long before effects appear?
In animal studies, respiratory stimulant effects of α-lobeline were observed to last approximately 90 seconds after administration. Human data on the onset and duration of effects are lacking.
Research Sources
- https://restorativemedicine.org/library/monographs/lobelia/ – This monograph reviews Lobelia inflata, highlighting animal studies where α-lobeline caused transient respiratory stimulation in horses, pigs, and rabbits. It notes the limited human data and the absence of robust clinical trials, classifying the evidence quality as moderate due to reliance on animal models.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC5611621/ – This experimental phytochemical analysis by Joshi et al. (2011) investigated the essential oil of Lobelia pyramidalis. It found moderate antimicrobial activity against Staphylococcus aureus with a minimum inhibitory concentration (MIC) of 3.12 mg/ml, but emphasizes that these are in vitro findings without clinical validation.
- https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2021.638210/full – This review by Zheng et al. (2021) summarizes phytochemicals from Lobelia species, identifying compounds with in vitro anti-inflammatory, cytotoxic, and anti-diabetic activities. It underscores that these findings are preliminary and lack clinical trials, thus limiting their applicability to human health.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7982472/ – This source, likely related to the Zheng et al. (2021) review, further details the identification of bioactive compounds from Lobelia species. It highlights in vitro evidence for various pharmacological activities but consistently points out the absence of human clinical data to support these effects.
- https://www.healthline.com/nutrition/lobelia – This article provides a general overview of Lobelia, including its traditional uses and potential side effects. It serves as a consumer-oriented resource, summarizing known information about the plant, particularly its toxicity at high doses and common adverse reactions.