Sitaraghav R. Gollapudi

Antimicrobial pterocarpans of nigerian Erythrina mildbraedii

Abstract Bioassay-directed fractionation of ethanolic extracts of the roots of Erythrina mildbraedii , a plant used in the indigenous system of medicine in Nigeria, resulted in the isolation of the previously known pterocarpans erythrabyssin-II and isoneorautenol and the new pterocarpans erybraedins A, B, and C. The structures of the new compounds were determined by chemical transformations and/or spectroscopy and their in vitro antimicrobial spectra and potencies are reported.

Erycristin, a new antimicrobial petrocarpan from Erythrina crista-galli

Abstract Bioassay-directed fractionation of ethanolic extracts of the stern bark of Erythrina crista-galli resulted in the isolation of a new pterocarpan, erycristin, and two previously known pterocarpans, sandwicensin and erythrabyssin-II. The structure of erycristin was determined by spectroscopic examination and by chemical transformation of sandwicensin. The absolute stereochemistry of erycristin was established by circular dichroism measurements. Erythrabyssin-II diacetate was converted to erycristagallin diacetate, supporting the previous proposed structure of erycristagallin.

Isolation and Identification of Higher Plant Agents Active in Antimutagenic Assay Systems: Glycyrrhiza Glabra

The reproduction and maintenance of identity of species are biological imperatives, and it is not surprising that there exist mechanisms to minimize or repair the deleterious influence of noxious chemicals in the environment on DNA. Animals tend to defend themselves through the use of enzymes which intercept aggressive chemicals and convert them to less dangerous substances. Animal cells also contain a variety of preformed smaller molecular weight chemicals which can react with oxidized species and free radicals and convert them to less virulent electrophiles (1). It is now becoming clear that higher plants also contain a variety of preformed secondary metabolites which represent a structurally diverse array of antimutagenic and desmutagenic compounds (6). Many, but not all, would appear to be enzyme inhibitors or antioxidants. Since a number of plant constitu-ents are mutagenic (18), it seems reasonable that higher plants should also contain molecules capable of antimutagenicity so as to survive the effects of their own metabolism. Study of such substances has the potential of revealing much interesting molecular detail about the processes of mutagenesis and antimutagenesis. A rather more distant hope is that such substances might be safe enough to provide protection for individuals perceived to be at risk. This would appear to be the case with a number of minor anticarcinogenic constituents consumed as part of our diet (4, 20).

Isoflavonoids and a cinnamyl phenol from root extracts of Erythrina variegata

Abstract Bioassay-directed fractionation of the roots of Erythrina variegata resulted in the isolation of several known compounds: warangalone (scandenone),5,7,4′-trihydroxy-6,8-diprenylisoflavone, erycristagallin, erythrabys-sin-II, phaseollin, phaseollidin, and isobavachin. A new cinnamylphenol, eryvariestyrene, was also isolated and characterized by spectroscopic means.

Amorphastilbol, an antimicrobial agent from Amorpha nana

Abstract Bioassay-directed fractionation of Amorpha nana demonstrated that the anti Gram positive/antitubercular constituent is amorphastilbol. The chemical structure of amorphastilbol was confirmed by chemical transformation to known ( Radula variabilis ) dihydroamorphastilbol and its methyl ether. Inactive 3,5-dihydroxy-7,4′-dimethoxyflavone was detected in this plant for the first time and identified by interconversion with kaempferol. All compounds were evaluated in vitro for antimicrobial spectrum and potency.

A reinvestigation of the taxol content of himalayan taxus wallichiana zucc. and a revision of the structure of brevifoliol.

Abstract When taken at the appropriate time and place, biorenewable leaves of the abundant Himalayan yew, Taxus wallichiana Zucc., contain significant quantities (0.045–0.130%) of taxol and other useful taxanes including 10-deacetylbaccatin III and brevifoliol. Spectroscopic reexamination of brevifoliol indicates that its structure must be revised to 11 . This makes brevifoliol and recently reported taxchinin A ( 12 ) close molecular relatives.

Antitumor Properties of Phenothiazines

The purpose of this review is to describe and evaluate the antineoplastic properties of phenothiazines. The present research studies suggest that many phenothiazines do not show significant antitumor and antineoplastic activity and so they cannot be used as potential drugs to treat cancer. However some of their derivatives help indirectly in decreasing cytotoxic effects caused by radiation and other chemical carcinogens. Additionally, some phenothiazine derivatives provide protection against cancers caused by metabolic activation of carcinogens such as dimethylbenzanthracene. The selective accumulation of phenothiazine derivatives in certain tissues such as brain and melanoma tumors may provide an effective treatment of such tumors. Current studies suggest that highly potent phenothiazine derivatives can be made by nitro substitution on the aromatic ring of phenothiazines.

Antimicrobial agents from higher plants: two dimethylbenzisochromans from Karwinskia humboldtiana

Abstract Two new antimicrobial dimethylbenzisochromans were isolated from the roots of Karwinskia humboldtiana together with the known 7-acetyl-6,8-dimethoxy-3-methyl-l-naphthol. The structures and absolute configurations were determined by spectroscopic examination and by chemical transformation to the known quinones eleutherin and 7-methoxyeleutherin.

Glepidotin C: A minor antimicrobial bibenzyl from Glycyrrhiza lepidota

Abstract Further examination of chromatographic residues from an earlier study of the antimicrobial constituents of American licorice. Glycyrrhiza lepidota , resulted in the isolation of a small amount of a new, weakly active, bibenzyl named glepidotin C. Spectroscopic measurements led to the assignment of the structure of this compound as 2-(2-hydroxy-3-methylbut-3-enyl)-5-(1-phenylethyl)-1,3-benzenediol.

Antimicrobial agents from higher plants: the isolation and structural characterization of two additional pterocarpan antimicrobial agents from Nigerian Erythrina mildbraedii

Examination of bioactive mother-liquors from previous large scale experiments on the antimicrobial agents from the Nigerian medicinal plant, Erythrina mildbraedii, led to the isolation and structural characterization of two new pterocarpans, erybraedin D and E. Erybraedin D was initially isolated as its apparently artifactual hemiethyl phthalate ester. Both new pterocarpans possess marginal antimicrobial potency in vitro