Sabira Begum

Triterpenoids from the leaves of Psidium guajava

Two triterpenoids, 20beta-acetoxy-2alpha,3beta-dihydroxyurs-12-en-28-oic acid (guavanoic acid, 3), and 2alpha,3beta-dihydroxy-24-p-z-coumaroyloxyurs-12-en-28-oic acid (guavacoumaric acid, 7), along with six known compounds 2alpha-hydroxyursolic acid (1), jacoumaric acid (2), isoneriucoumaric acid (4), asiatic acid (5), ilelatifol D (6) and beta-sitosterol-3-O-beta-D-glucopyranoside (8), have been isolated from the leaves of Psidium guajava. Their structures were determined through spectroscopic methods. Compound 5 showed dose-dependent (10-500 microg/ml) spasmolytic activity in spontaneously contracting isolated rabbit jejunum preparations.

Gastrointestinal, selective airways and urinary bladder relaxant effects of Hyoscyamus niger are mediated through dual blockade of muscarinic receptors and Ca2+ channels.

This study describes the spasmolytic, antidiarrhoeal, antisecretory, bronchodilatory and urinary bladder relaxant properties of Hyoscyamus niger to rationalize some of its medicinal uses. The crude extract of H. niger seeds (Hn.Cr) caused a complete concentration‐dependent relaxation of spontaneous contractions of rabbit jejunum, similar to that caused by verapamil, whereas atropine produced partial inhibition. Hn.Cr inhibited contractions induced by carbachol (1 μm) and K+ (80 mm) in a pattern similar to that of dicyclomine, but different from verapamil and atropine. Hn.Cr shifted the Ca2+ concentration–response curves to the right, similar to that caused by verapamil and dicyclomine, suggesting a Ca2+ channel‐blocking mechanism in addition to an anticholinergic effect. In the guinea‐pig ileum, Hn.Cr produced a rightward parallel shift of the acetylcholine curves, followed by a non‐parallel shift with suppression of the maximum response at a higher concentration, similar to that caused by dicyclomine, but different from that of verapamil and atropine. Hn.Cr exhibited antidiarrhoeal and antisecretory effects against castor oil‐induced diarrhoea and intestinal fluid accumulation in mice. In guinea‐pig trachea and rabbit urinary bladder tissues, Hn.Cr caused relaxation of carbachol (1 μm) and K+ (80 mm) induced contractions at around 10 and 25 times lower concentrations than in gut, respectively, and shifted carbachol curves to the right. Only the organic fractions of the extract had a Ca2+ antagonist effect, whereas both organic and aqueous fractions had anticholinergic effect. A constituent, β‐sitosterol exhibited Ca2+ channel‐blocking action. These results suggest that the antispasmodic effect of H. niger is mediated through a combination of anticholinergic and Ca2+ antagonist mechanisms. The relaxant effects of Hn.Cr occur at much lower concentrations in the trachea and bladder. This study offers explanations for the medicinal use of H. niger in treating gastrointestinal and respiratory disorders and bladder hyperactivity.

Studies on the constituents of the leaves of Nerium oleander on behavior pattern in mice

Fresh, undried and uncrushed leaves of Nerium oleander were subjected to methanol extraction and bioassay directed fractionation. This led to the isolation of two purified fractions namely, B-1 and B-3. Fractions B-1 and B-3 were studied with respect to their actions on the central nervous system and behavior pattern in mice. Both fractions were found to produce reduction in locomotor activity, rota rod performance and potentiation of hexobarbital sleeping time. These fractions also showed analgesic activity. When tested against picrotoxin induced convulsions fraction B-1 showed 40% protection, while fraction B-3 exhibited 60% protection against bicuculline induced convulsions. These findings suggest that both fractions possess a CNS depressant action.

Bio-active cardenolides from the leaves of Nerium oleander.

A bioactivity directed isolation of the methanolic extract of the fresh, uncrushed leaves of Nerium oleander showing a central nervous system (CNS) depressant effect in mice has been undertaken. As a result, four CNS depressant cardenolides including a new cardenolide, neridiginoside and three known constituents, nerizoside, neritaloside and odoroside-H, have been isolated which exhibited CNS depressant activity in mice at a dose of 25 mg/kg. The structure of neridiginoside was elucidated as 3 beta-O-(D-diginosyl)-5 beta, 14 beta-dihydroxy-card-20(22)-enolide, using spectroscopic methods including one-dimensional and two-dimensional NMR (COSY-45, NOESY, J-resolved, HMQC and HMBC). The known compounds have been indentified through spectral studies and comparison of data with those reported in the literature.

Study of the in vitro antimicrobial activity of harmine, harmaline and their derivatives

Peganum harmala L. (Zygophyllaceae), commonly known as harmal, grows wild in the semiarid regions of IndoPakistan subcontinent, Iran and Africa. Its different parts have been used in traditional systems of medicine for the treatment of a variety of human ailments (Dymock et al., 1890; Chopra et al, 1956). Peganum harmala is known to contain four main alkaloids, namely harmaline (Ci3Hi40N2) reported by Goebel, harmine (Ci3H120N2) isolated by Fritsche, harmalol (Ci2Hi20NZ) noted by Goebel and prepared by Fischer from harmaline, and peganine (C,,Hi20Nz) obtained by Merk and later found to be identical with vasicine isolated earlier by Hooper (Henry, 1949). Harmal alkaloids have been reported to possess hypotensive activity (Codding, 1983), while earlier the seeds have been shown to have a marked physiological activity (Elger, 1928) and have been used for curative purposes (El-Saad and EI-Rifaie, 1980). Preliminary work on the antimicrobial study of the crude ethanolic extract of seeds of Peganum harmala was perfomed by different groups of workers (Ross et al., 1980; Al-Sharma and co-

Phytochemical studies on the seed extract of Piper nigrum Linn.

The petroleum ether extract of dried ground seeds of Piper nigrum Linn. and some column fractions of this extract were subjected to GC and GC-MS analysis, resulting in the identification of fourteen compounds (1–14) by using NIST Mass spectral search program 1998 and the Kovats retention indices. Ten of the compounds (1, 2, 4–12) are reported for the first time from this plant. All the fractions showed insecticidal activity against the fourth instar larvae of Aedes aegypti and against the fourth instar larvae of Anopheles stephensi Liston, determined by the WHO method.

An amide from fruits of Piper nigrum

Abstract A new amide, N -isobutyl amide of octadeca- trans -2- cis -4-dienoic acid has been isolated from the dried and crushed fruits of Piper nigrum , along with the known alkaloid, piperine. Complete assignments of the protons and carbons of the new amide and piperine have been made based on 2D NMR studies.

Two cytotoxic pentacyclic triterpenoids from Nerium oleander

The isolation and structure elucidation of two novel cytotoxic pentacyclic triterpenoids cis-karenin (3β-hydroxy-28-Z-p-coumaroyloxy-urs-12-en-27-oic acid) and trans-karenin (3-β-hydroxy-28-E-p-coumaroyloxy-urs-12-en-27-oic acid) from the leaves of Nerium oleander is described.

Triterpenes, A sterol and A monocyclic alcohol from Momordica charantia

Abstract Five new compounds have been isolated from the fresh fruits of Momordica charantia and their structures elucidated through spectroscopic studies. These include three pentacyclic triterpenes 13-hydroxy-28-methoxy-urs-11-en-3-one (momordicin), 13β,28-epoxy-urs-11-en-3-one (momordicinin), 24-[1′-hydroxy,1′-methyl-2′-pentenyloxyl]-ursan-3-one (momordicilin), a sterol 3β-hydroxy-stigmasta-5,14-dien-16-one (momordenol) and a monocyclic alcohol 1-hydroxy-1,2-dimethyl-2-[8′,10′-dihydroxy-4′,7′-dimethyl-11′-hydroxy methyl-trideca]-3-ethyl-cyclohex-5-en-4-one (momordol).

Pentacyclic triterpenoids from the aerial parts of Lantana camara and their nematicidal activity.

Two new olean‐12‐ene triterpenoids, camarolic acid (1) and lantrigloylic acid (2), have been isolated from the aerial parts of Lantana camara, along with ten known triterpenes, namely, camaric acid, lantanolic acid, lantanilic acid, pomolic acid, camarinic acid, lantoic acid, camarin, lantacin, camarinin, and ursolic acid. The new compounds have been characterized as 3,25‐epoxy‐3α‐hydroxy‐22β‐{[(S)‐3‐hydroxy‐2‐methylidenebutanoyl]oxy}olean‐12‐en‐28‐oic acid (1) and 3,25‐epoxy‐3α‐hydroxy‐22β‐[(3‐methylbut‐2‐enoyl)oxy]olea‐9(11),12‐dien‐28‐oic acid (2) through spectroscopic studies and a chemical transformation. Seven of the constituents, namely pomolic acid, lantanolic acid, lantoic acid, camarin, lantacin, camarinin, and ursolic acid, were tested for nematicidal activity against root‐knot nematode Meloidogyne incognita. Pomolic acid, lantanolic acid, and lantoic acid showed 100% mortality at 1 mg/ml concentration after 24 h, while camarin, lantacin, camarinin, and ursolic acid exhibited 100% mortality at this concentration after 48 h. These results are comparable to those obtained with the conventional nematicide furadan (100% mortality at 1 mg/ml concentration after 24 h).