M. Akram Khan

Chemical composition and medicinal properties of Nigella sativa Linn.

The black cumin or Nigella sativa L. seeds have many acclaimed medicinal properties such as bronchodilatory, hypotensive, antibacterial, antifungal, analgesic, anti-inflammatory and immunopotentiating and are universally accepted as a panacea. This review article has surveyed the relevant literature on Nigella sativa from 1960-1998 and examines the scientific evidence for these medicinal claims and highlights areas in need of research.

Chemical composition of Nigella sativa Linn: Part 2 Recent advances

The black cumin or Nigella sativa L. seeds have many acclaimed medicinal properties such as bronchodilatory, hypotensive, antibacterial, antifungal, analgesic, anti-inflammatory and immunopotentiating. This review article is an update on the previous article published on Nigella sativa L. in this journal in 1999. It covers the medicinal properties and chemical syntheses of the alkaloids isolated from the seeds of the herb.

Synthesis and anti-inflammatory properties of some aromatic and heterocyclic aromatic curcuminoids

A variety of novel aromatic and heterocyclic aromatic curcuminoids were synthesised, characterised and their anti-inflammatory activities (AIA) determined in vivo. Some of these compounds also were tested for inflammatory mediator production. The AIA of the main representatives of these compounds were assessed by oral administration to female Wistar rats using (a) acute carrageenan-induced paw oedema, (b) chronic adjuvant arthritis (therapeutic mode), and (c) anti-pyretic activity assessed in the yeast pyrexia. Gastric ulceration was determined in pre-inflamed rats. Natural curcumin showed modest aspirin-like anti-inflammatory activity which was enhanced when co-administered with the PGE(1) analogue misoprostol as a synergist. In contrast, four novel curcuminoids (RK-97, RK-103, RK-104 and RK-106) in which the bis-methoxy-phenyl group of curcumin was replaced with bis-dimethoxybutenolidyl-(ascorbate), bis-naphthyl, and bis-furanyl derivatives, respectively, had potent activity in the anti-arthritic assay with little gastric or systemic toxicity, compared with the vehicle-treated controls. Of the curcuminoids the furan RK-106 was the only compound to inhibit production of TNFα and IL-1β in a monocytic cell-line THP-1 in vitro. The inactivity of RK-106 on the production of PGE(2) may be related to its absence of gastrotoxicity. None of the curcuminoids exhibited anti-pyretic activity and this may also be related to its insensitivity to PGE(2). Thus, these novel curcuminoids, such as RK-106, may warrant the development of new low gastro-toxic anti-inflammatory agents with selective inhibitory activity of cytokine inflammatory mediators.

Alkenyl sulphoxides as precursors to cyclopentenones and prostanoid β-side chains

Abstract Conjugate additions of enolate anions to α,β-unsaturated sulphoxides followed by sulphoxide-ketone transformations provided simple syntheses of cyclopentenones, and 2-phenylsulphinyloct-1-en-3-one provided a convenient electrophilic prostanoid β-side chain precursor.

The formation of lactams from l-ascorbic acid

Abstract 2,3- O -Dimethyl-6- O - p -toluenesulphonyl- l -ascorbic acid reacted with the primary amines n -butylamine, benzylamine and cyclohexylamine at room temperature to give the 1-alkyl-2,3-dimethoxy-4-hydroxy-4-[1′-(2′-aminoalkyl)ethyl]but-3-enimides in 64, 58 and 60% yields, respectively, after chromatographic purification. However, 2,3- O -dimethyl-5,6-di- O - p -toluenesulphonyl- l -ascorbic acid reacted with n -butylamine, benzylamine and cyclohexylamine to give the 1-alkyl-2,3-dimethoxy-4-hydroxy-4-[1′-(2′-aminoalkyl)ethyl]but-3-enimides in 61, 74 and 75% yields, respectively. The absolute configuration for one of the products was established by X-ray crystallography.

Conjugate additions to α,β-unsaturated sulphoxides: syntheses of cyclopentenones and 9-deoxyprostanoids

1,4- Dicarbonyl compounds, and hence cyclopentenone derivatives, were prepared by conjugate additions of enolate and related anions to α,β-unsaturated sulphoxides, followed by sulphoxide–ketone transformations. These transformations involved trapping the intermediate α-sulphinyl carbanions with dimethyl disulphide to give thioacetal monoxide derivatives, or Pummerer rearrangements of the sulphoxides to give alkenyl sulphides. 3-Substituted 2-ethoxycarbonylcyclopentenones prepared in this way were converted into 9-deoxyprostanoids and their 12-ethoxycarbonyl derivatives, the latter by use of 2-phenylsulphinyloct-1-en-3-one as an electrophilic prostanoid β-side-chain precursor.

Chemistry and Biochemistry of Terpenoids from Curcuma and Related Species

Several curcuminoids have been identified from rhizome of the common spice Curcuma longa (Zingaberaceae) and related plant species. Curcuminoids are known to display several pharmacological properties summed up in numerous papers and reviews. In addition to curcuminoids, more than 250 mono-, sesqui- di-, and triterpenoids have been identified from curcuma species. These lipophilic compounds have better absorption than curcuminoids and also exhibit a wide spectrum of pharmacological properties. Little attention has been paid to these lipophilic compounds, which may be as physiologically active, if not more, as curcuminoids. This review focuses on Curcuma terpenoids and their physiological properties.

SIMPLE STEREOSELECTIVE SYNTHESIS OF (1E, 3Z)-4-(SUBSTITUTED)AMINO 1,3-DIETHOXYCARBONYL-1,3-BUTADIENES

Abstract Ethyl propynoate reacted with esters of amino acids in methanolic solutions containing sodium acetate to yield the title compounds 1a-d in 40–52% yields. Some aromatic amines similarly reacted with ethyl propynoate to yield the dienes 3a-h in relatively poor yields (17–45%).