Shaista Perveen

A sterol glycoside from marine green alga Codium iyengarii

Abstract Chemical investigation of the hexane soluble portion of marine green alga Codium iyengarii has resulted in the isolation of a new sterol glycoside, 3- O -β- d -galactopyranosyl-stigmasta-5,25-diene together with clerosterol. The structures of both the compounds were established on the basis of their spectroscopic data as well as by chemical means.

Sterols from marine green alga Codium decorticatum

Abstract Three new sterols, named decortinol, isodecortinol and decortinone, have been isolated from the ethyl acetate soluble portion of the extract of a marine green alga Codium decorticatum . Clerosterol and 3- O -β- d -galacto-pyranosyl clerosterol were also extracted for the first time from this alga. The structures of all the compounds were assigned on the basis of spectroscopic data.

Analgesic and anti-inflammatory activities of Piper nigrum L.

OBJECTIVE To evaluate and compare the analgesic and anti-inflammatory activity of pure compound, piperine along with hexane and ethanol extracts of Piper nigrum L. fruit in mice and rats. METHODS The analgesic activity was determined by tail immersion method, analgesy-meter, hot plate and acetic acid induced writhing test. While the anti-inflammatory activity was evaluated by carrageenan-induced paw inflammation in rats. RESULTS Piperine at a dose of 5 mg/kg and ethanol extract at a dose of 15 mg/kg after 120 min and hexane extract at a dose of 10 mg/kg after 60 min exhibited significant (P<0.05) analgesic activity by tail immersion method, in comparison to ethanol extract at a dose of 10 mg/kg using analgesy-meter in rats. However, with hotplate method, piperine produced significant (P<0.05) analgesic activity at lower doses (5 and 10 mg/kg) after 120 min. A similar analgesic activity was noted with hexane extract at 15 mg/kg. However, in writhing test, ethanol extract significantly (P<0.05) stopped the number of writhes at a dose of 15 mg/kg, while piperine at a dose of 10 mg/kg completely terminated the writhes in mice. In the evaluation of anti-inflammatory effect using plethysmometer, piperine at doses of 10 and 15 mg/kg started producing anti-inflammatory effect after 30 min, which lasted till 60 min, whereas hexane and ethanol extracts also produced a similar activity at a slightly low dose (10 mg/kg) but lasted for 120 min. CONCLUSIONS It is concluded from the present study that Piper nigrum L possesses potent analgesic and anti-inflammatory activities.

Steroidal saponins from Asparagus dumosus

A new steroidal saponin, dumoside, characterized as (20S)-3 beta, 16 beta-dihydroxy pregn-5-ene-22-carboxylic acid (22, 16)-lactone-3-O-beta-chacotrioside, was isolated from the whole plant of Asparagus dumosus Baker and the structure was deduced from spectral data. In addition to dumoside three more steroidal saponins characterized as 3 beta-dihydroxy pregn-5,16-dien-20-one 3-O-beta-chacotrioside, 3 beta, 22 alpha, 26-trihydroxyfurost-5-ene-3-O-beta-chacotrioside-26-O- beta-D-glucopyranoside and its corresponding 22 alpha-O methoxy analogue were also isolated for the first time from this source. The structures have been identified with the help of FAB-MS, 1H NMR, 13C NMR and extensive 2D NMR spectroscopy, as well as comparison with reported spectroscopic data.

Saponins from the leaves of Guaiacum officinale

Abstract Guaiacin, C, D, E and F, four new saponins, have been isolated from the leaves of Guaiacum officinale and characterised on the basis of chemical investigation and spectroscopic studies as 3- O -[α- l -rhamnopyranosyl(1 → 2)α- l -arabinopyranosyl(3 → 1)β- d -glucopyranosyl]-30-norolean-12,20(29)-dien-28-oic acid; 3- O -[α- l -rhamnopyranosyl-(1 → 2)α- l -arabinopyranosyl(3 → 1)β- d -glucopyranosyl]-30-norolean-12,20(29)-dien-28- O -[β- d -glucopyranosyl] ester; 3- O -[β- d -glucopyranosyl(1 → 2)α- l -arabinopyranosyl(3 → 1)β- d -glucopyranosyl]-30-norolean-12,20(29)-dien-28- O -[β- d -glucopyranosyl]ester; 3- O -[β- d -glucopyranosyl(1 → 2)α- l -arabinopyranosyl(3 → 1)β- d -glucopyranosyl] oleanolic acid-28- O -[β- d -glucopyranosyl]ester.

Somalenone, A C26 sterol from the marine red alga Melanothamnus somalensis

Abstract A new C 26 sterol named as somalenone has been isolated from the marine red alga Melanothamnus somalensis and characterized as 24-norcholest-5-en-3,7-dione. Cholesterol, 7-oxo-cholesterol and 24-methylenecholesterol were also isolated from the alga.

Brominated sesquiterpene metabolites of Hypnea pannosa (Gigartinales, Rhodophyta)

A chloroform extract of freeze-dried Hypnea pannosa J. Ag., collected from the intertidal region near Karachi, Pakistan, furnished three bromine-containing secondary metabolites. These were characterised, using spectroscopic techniques, as 10-bromo-7, 12-dihydroxy-Δ3, 4-laurene, filiformin and filiforminol. This is the first report of halogenated terpenoids from the genus Hypnea.

Chemical Constituents of Endarachne binghamiae (Scytosiphonales, Phaeophyta) from the Karachi Coast

Hexadecanoic acid, 24-methyIene cholesterol and D-mannitol were isolated and their identities confirmed from methanolic extracts of Endarachne binghamiae J. Agardh collected intertidally on the coast of Pakistan near Karachi.

Isolation and Structural Studies on Chemical Constituents from Some Plants and Marine Organisms of Pakistan

In the meeting held in January 1987 I presented before you [1] the work done in our group on the isolation and structure elucidation of new natural products. Today I would like to discuss the structure of new natural products which have been isolated by us in the last few years which were not included in my last lecture.