Lobelia

Loaded adsorbents Loadstone Lobelia Loblolly pine Lobster... 

The presence of alkaloids in Lobelia injlata, Linn., was first recorded by Proctor. Lobeline was prepared by Lewis as a basic oil from which Siebert made and analysed a series of salts and proposed the formula, CigHjsOjN. In 1921 Bohringer and Sohne protected a process for the isolation and separation of three alkaloids, a-, 3 and y-lobelines. In the same year Wieland published the first of a series of papers in which is described the isolation of several groups of alkaloids, to most of which constitutional formulae have been assigned and, in some cases, confirmed... 

Lobelia is recognised in several pharmacopoeias, but standards are not usually prescribed for its alkaloidal content, which should. be from 0-3 to 0-4 per cent. 

Numerous methods for the alkaloidal assay of lobelia and its galenical preparations have been published and two recent critical surveys, by a special committee of the Society of Public Analysts and by Caulkin, indicate that the process of Markwell is satisfactory. Processes for the isolation and separation of the various alkaloids have been protected by patent. Balandin states that Lobelia sessiliflora contains less alkaloid than L. injiata but yields a high-quality lobeline. 

According to Wieland, the typical lobelia alkaloids so far isolated and examined belong to three groups (Table A), all of which can be represented by the general Formula I. 

LELOBINE AND LOBININE GROUPS. These include the minor alkaloids of lobelia isolated from factory residues accumulated during the manufacture of lobeline. Their isolation and separation involve complicated processes of fractionation for which the original paper should be consulted. Their inter-relationships (Table A, p. 23 and general formula, I, p. 24) are similar to those among members of the lobeline group, but the effect of the presence of three or more asymmetric carbon atoms is more evident, thus there are already known six forms of the basic dihydric alcohol, lelobaiiidine. 

Lobinaline, C2gH3gON2. This alkaloid was isolated by Manske from Lobelia cardinalis, L. It crystallises with difficulty in prisms, m.p. 94-5°, + 22-3° (CHCI3), yields a hydrochloride, B. HCl, 1-5 HjO, m.p. 220°, and on oxidation by permanganate yields benzoic acid. 

Pyridine Group. Piperine, Piperovatine, Leucenol, Mimosine, Alkaloids of Ricinus communis, Foenugrec, vy eca Nut, Hemlock, Lobelia, Tobacco (Nicotiana spp.). Anabasis aphylla, Pomegranate Root Bark. ... 

Other examples of syntheses under physiological conditions will be found under arecaidine, lobelia, papaverine, cusparia bark alkaloids, harmala alkaloids, rutascarpine and yohimbine. 

From a vast number of alkaloids containing the /I -pyrroline or piperideine ring in the molecule, alkaloids myosmine (197) and lobinaline (i/5) (198) of Lobelia cardinalis L. may be mentioned. 

Lobeline Lobelia inf lata, -(also non-specific actions)... 

From Lobelia inflata L. by extraction of the slightly acidic extract of the drug with chloroform and subsequent purification. 

Lobelia cathechu guvacoline guvacine Lobelia inflata Lobeline Nicotinic ACh agonist... 

Lobelia (Lobelia inflata), also referred to as Indian tobacco, is an annual or biennial herb that grows from 30 to 60 cm in height (Gruenwald et al. 1998). Its leaves are green or yellowish and range from ovate to lanceolate in shape (figure 4.12). Its flowers are a pale violet-blue and the fruit is an ovoid capsule containing many small brown seeds. 

Lobelia was named after a Flemish botanist, Matthias L Obel (Robbers et al. 1996). Inflata refers to the hollow, distended fruit. It was also used by Native Americans as a substitute for tobacco. It was used medicinally by a group of physicians during the nineteenth century C.E. (Tyler 1994). However, due to toxicity and better treatments for tobacco dependence, lobelia is now rarely, if ever, indicated. Chemical Constituents... 

Lobelia contains 14 alkaloids, of which lobeline is the most significant (figure 4.13). Other alkaloids include lobelanine, lobelanidine, norlobelanine, and isolobinine. Another relevant chemical that is isolated from the leaves of lobelia is beta-amyrin palmitate. 

Lobeline is somewhat soluble in water, but not soluble in alcohol (Robbers et al. 1996). It is no longer used medicinally, but has been put in lozenges to assist in breaking the tobacco habit. Unfortunately, it has not been successful in this regard. Lobelia derivatives may cross the blood-brain barrier by passing through basic amine transporters... 

Lobelia (Lobelia inflata). Reprinted from Culbreth DMR. (1927). Materia Medica and Pharmacognosy, 7th ed. Philadelphia Lea Febiger. 

Another psychoactive constituent of lobelia, beta-amyrin palmitate, causes a release of norepinephrine in mouse brain synaptosomes, possibly releasing it from newly synthesized pools (Subarnas et al. 1993b). 

Electrophysiology Studies of the electrophysiological effects of lobelia are scant. In one study, increases were seen in low-frequency activity in the hippocampus but in higher-frequency activity in the amygdala (Sopranzi et al. 1991). 

Antidepressant Some animal models show antidepressant effects of lobelia extract (Subarnas et al. 1992). Similar to imipramine and mianserin, beta-amyrin palmitate shows antidepressant-like effects in the forced-swimming test (Subarnas et al. 1993a). Whereas mianserin and beta-amyrin palmitate reduce locomotor activity induced by methamphetamine, imipramine increases it. It potentiates sodium pentobarbital-induced sleep more potently than imipramine, but less than mianserin. Collectively, the effects of beta-amyrin palmitate in behavioral and physiological assays suggests it may work in a manner more similar to mianserin than imipramine. However, the mechanism of antidepressant-like effects of lobelia is uncertain. It may be through the beta-amyrin palmitate s ability to release norepinephrine (Subarnas et al. 1993b). An antidepressant effect of lobelia has not been established in humans. 

Similar to tobacco, lobelia may also have analgesic effects. However, it depends on the mode of administration (Damaj et al. 1997). Intrathecal lobeline produces analgesia on the tail-flick test, but subcutaneous administration is ineffective. On the other hand, subcutaneous lobeline dose-dependently enhances nicotine analgesia. Tolerance develops to this effect of lobeline after 10 days. Lobeline can also produce hyperalgesic effects when administered into the dorsal posterior mesencephalic tegmentum (Hamann and Martin 1994). However, the relevance of this to peripheral administration of lobelia is questionable because chronic injections (IP) of lobeline in rats induced no changes in tail-flick latencies (Sopranzi et al. 1991). 

Sopranzi N, De Feo G, Mazzanti G, Braghiroii L. (1991). [The biological and electrophysiological parameters in the rat chronicaiiy treated with Lobelia inflata L]. Clin Ter. 137(4) 265-68. 

Streufert S, Pogash R, Miller J, Gingrich D, Landis R, Lonardi L, Severs W, Roache JD. (1995). Effects of caffeine deprivation on complex human functioning. Psychopharmacology (Berlin). 118(4) 377-84. Stricherz ME, Pratt P. (1976). Betel quid and reaction time. Pharmacol Biochem Behav. 4(5) 627-28. Subarnas A, Oshima Y, Sidik, Ohizumi Y. (1992). An antidepressant principle of Lobelia inflata L. (Campanulaceae). J Pharm Sci. 81(7) 620-21. 

Subarnas A, Tadano T, Nakahata N, Aral Y, Kinemuchi H, Oshima Y, Kisara K, Ohizumi Y. (1993b). A possible mechanism of antidepressant activity of beta-amyrin palmitate isolated from Lobelia inflata leaves In the forced swimming test. Life Sci. 52(3) 289-96. 

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