Biomedical subjects
Publications and source records attributed to B L Sondengam.
From the root bark of Securidaca longepedunculata, a heptaoxygenated xanthone (1) has been isolated as well as two known xanthones (2) and (3) and two salicylic acid derivatives (4) and (5). The structure of 1 has been elucidated from 1H and 13C-NMR spectral data.
Phytochemical investigation of the stem bark extract of Boswellia papyrifera afforded two new stilbene glycosides, trans-4',5-dihydroxy-3-methoxystilbene-5-O-{alpha-L-rhamnopyranosyl-(1-->2)-[alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-glucopyranoside (1), trans-4',5-dihydroxy-3-methoxystilbene-5-O-[alpha-L-rhamnopyranosyl-(1-->6)]-beta-D-glucopyranoside (2), and a new triterpene, 3alpha-acetoxy-27-hydroxylup-20(29)-en-24-oic acid (3), along with five known compounds, 11-keto-beta-boswellic acid (4), beta-elemonic acid (7), 3alpha-acetoxy-11-keto-beta-boswellic acid (8), beta-boswellic acid (9), and beta-sitosterol (10). The stilbene glycosides exhibited significant inhibition of phosphodiesterase I and xanthine oxidase. The triterpenes (3-9) exhibited prolyl endopeptidase inhibitory activities.
Phytochemical investigations on the non-alkaloidal extracts of Mitragyna stipulosa bark has led to the isolation of a series of triterpenoids mainly consisting of quinovic acid ([structure: see text]) and its glycoside derivatives [structure: see text] and [structure: see text]. The other constituents isolated include alpha-amyrin, 3beta-acetyl ursolic acid and a mixture of oleanolic and ursolic acid and beta-sitosterol glucopyranoside. Their structures were identified by spectral and chemical studies and compounds [structure: see text] and [structure: see text] were, respectively, identified as quinovic acid 3-O-[beta-D-glucopyranoside] (quinovin glycoside C) and quinovic acid 3-O-[beta-D-quinovopyranoside]-27-O-[beta-D-glucopyranosyl] ester. Compounds [structure: see text] and [structure: see text] showed significant inhibitory activity against snake venom phosphodiesterase I.
The stem bark of Ochna afzelii furnished three biflavonoids among which two are new. Their structures were established from spectroscopic and chemical evidences.
Two known 7,8-dihydrobenzofuranones, aquilegiolide (1) and menisdaurilide (2), were isolated from Ouratea reticulata root bark.
Two new fatty acid glucosides, (3E,8Z)-8-carboxy-1-(O-beta-D-glucopyranosyl)-2,6-dihydroxytritriaconta-3,8-diene (1) and (8Z)-8-carboxy-1-(O-beta-D-glucopyranosyl)-3,4-epoxy-2,6-dihydroxytritriacont-8-ene (2), have been isolated from the root bark of Ochna calodendron and their structures elucidated by extensive two-dimensional NMR methods including HMQC, HMBC and NOESY experiments.
Bioassay-guided isolation of two new compounds, 3,4-methylenedioxy-3'-O-methyl-4'-O-glucoside ellagic acid (1) and the pteleoellagic acid derivative (2), from the stem bark of Pteleopsis hylodendron is reported along with 3,4-methylenedioxy-3'-O-methyl ellagic acid (3), 3,3'-di-O-methyl ellagic acid (4) and 3,3',4'-tri-O-methyl ellagic acid (5), which were obtained for the first time from this plant. The structures of these compounds were elucidated with the help of spectroscopic studies. Compounds 1 and 4 were found to have significant antioxidant activity, while compounds 1-4 showed antibacterial activity against different pathogenic bacteria.
Two new isoflavones, pentandrin (1) and pentandrin glucoside (2), were isolated from the stem barks of Ceiba pentandra along with beta-sitosterol and its 3-O-beta-D-glucopyranoside, which was isolated for the first time from this plant. The structures of these compounds were elucidated with the help of spectroscopic techniques, while the structure of 1 was unambiguously confirmed by single-crystal X-ray diffraction studies.
A new sesquiterpene lactone, drypemolundein A and a new friedelane derivative, drypemolundein B, along with seven known compounds have been isolated from the whole stems of Drypetes molunduana Pax and Hoffm. Their structures were established on the basis of one- and two-dimensional NMR, homo- and hetero-nuclear spectroscopic evidence.
Two new chromone glycosides, schumanniofiosides A and B have been isolated from the root bark of Schumanniophyton magnificum and their structures shown to be 2-methyl-5,7-dihydroxychromone 5-O-beta-D-glucopyranoside and 2-methyl-5,7-dihydroxychromone 7-O-beta-D-glucopyranosyl-(1----2)-apiofuranoside, respectively. The structures were elucidated by a combination of spectral data and chemical degradation.
Studies of the methylated ethyl acetate extract of the trunk wood of MYRIANTHUS ARBOREUS (Cec-ropiaceae) have resulted in the isolation of five known pentacyclic triterpenes and a new lignan cinnamate. The structural elucidation of the new compound has been effected on grounds of the interpretation of spectroscopic data and alkaline hydrolysis.
Six pentacyclic triterpenic acid methyl esters have been isolated from the methylated ethyl acetate extract of the trunk wood of MUSANGA CECROPIOIDES, as well as a triterpene saponin of the same group. One of them, cecropic acid methyl ester, is new. The structures of these compounds have been established from interpretation of spectral data or chemical transformations. The known triterpenes include euscaphic and tormentic acid methyl esters, already isolated from the root wood of the plant, methyl cecropiaceate, and methyl pomolate, already obtained from the stem bark, and methyl arjunolate and beta- D-glucosyl tormentate, encounted in this plant for the first time.
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The stem bark of Teclea ouabanguiensis has yielded six triterpenoids, two of which are new. The known compounds were identified spectroscopically as 7-deacetylazadirone (2), 7-deacetylproceranone (3), tecleanin, (4), and lupeol. The novel compounds include the tetranortriterpenoids, 7-deacetoxy-7-oxoazadirone (1), and ouabanginone (5). The biogenetic significance of the presence of these limonoids in T. ouabanguienis is discussed.