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Biomedical subjects

C W Beecher

Publications and source records attributed to C W Beecher.

22 records · Page 2Linked to original sources
PubMed1993

Isolation of echinocystic acid-3-O-sulfate, a new triterpene, from Tetrapleura tetraptera, and evaluation of the mutagenic potential of molluscicidal extracts and isolates.

A known triterpene glycoside, 3-O-[beta-D-glucopyranosyl-(1"-6')-2'-acetamido-2'-deoxy-beta-D-gluco pyranosyl]olean-12-en-28-oic acid [3], and new sulfated triterpene, echinocystic acid-3-O-sodium sulfate [4], have been isolated from the stem bark of Tetrapleura tetraptera. Compound 3 was 100% lethal to Biomphalaria glabrata at 20 ppm, while 4 was not molluscicidal at the same concentration. In a forward mutation assay utilizing Salmonella typhimurium strain TM677, T. tetraptera stem bark extracts were found to be mutagenic in the absence of a metabolic activating system (S-9). An MeOH extract of the fruit exhibited weak mutagenic activity only in the presence of S-9. The stem bark isolates, which included aridanin [1], 3-O-(2'-acetamido-2'-deoxy-beta-D-glucopyranosyl)echinocystic acid [2], and compounds 3 and 4, were not mutagenic either with or without metabolic activation.

Animals↗
PubMed1993

Novel antimitotic dibenzocyclo-octadiene lignan constituents of the stem bark of Steganotaenia araliacea.

By means of activity-directed chromatographic fractionation using cultured astrocytoma (ASK) cells, six dibenzocyclo-octadiene lignans were isolated from Steganotaenia araliacea stem bark. In addition to the most abundant analogue, steganangin [1], two other known compounds, steganacin [3] and steganolide A [6], and three new compounds, episteganangin [2], steganoate A [4], and steganoate B [5], were obtained. Episteganangin [2] was chemically correlated with the known ketone steganone [7]. All of these compounds demonstrated cytotoxic activity when tested against a panel of eleven human tumor cell lines, with the exception of steganoate A [4]. The magnitude of this activity tended to correlate with antimitotic activity observed with the ASK assay and in vitro inhibition of microtubule assembly. Steganacin [3] was less cytotoxic than colchicine, but more active in these latter two assay systems.

Animals↗
PubMed1991

Can ethnopharmacology contribute to the development of new anticancer drugs?

Ethnopharmacologic and ethnomedical information has been poorly utilized in the past in the search for new and effective treatments for cancer. In spite of this, plants have been a very viable source of clinically useful compounds, leads for synthetic modification and tools for mechanistic studies. In this paper, a new strategy for the discovery of anticancer agents from plants is proposed in which ethnomedical information is correlated against pertinent published chemical and biological information, resulting in a prioritization of plants for collection. Authenticated plants are extracted and the extracts tested in a broad array of more than 20 human cancer cell and mechanism-based assays through a cooperative research program involving a university, a research institute and a pharmaceutical company. Bioactivity-directed fractionation will be carried out at all three sites, with a view to identifying novel compounds which will serve as candidates for preclinical testing.

Animals↗