Securidacaxanthone A, a heptaoxygenated xanthone from Securidaca longepedunculata.

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.

Chromone glycosides from Schumanniophyton magnificum.

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.

Biflavonoids from Ochna afzelii.

The stem bark of Ochna afzelii furnished three biflavonoids among which two are new. Their structures were established from spectroscopic and chemical evidences.

New isoflavones from Ceiba pentandra.

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.

Sesquiterpene lactone and friedelane derivative from drypetes molunduana.

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.

7,8-Dihydrobenzofuranones from Ouratea reticulata.

Two known 7,8-dihydrobenzofuranones, aquilegiolide (1) and menisdaurilide (2), were isolated from Ouratea reticulata root bark.

Two new fatty acid glucosides from the root bark of Ochna calodendron.

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.

Bioactive constituents from Boswellia papyrifera.

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.

Limonoids of Teclea ouabanguiensis.

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.

A Contribution to the Phytochemistry of Zanthoxylum tessmannii1.

Root bark extracts of ZANTHOXYLUM TESSMANNII (Engl.) Ayafor COMB. NOV. (Syn. FAGARA TESSMANNII Engl.) yielded, besides chelerythrine, dihydrochelerythrine, fagaramide and lupeol previously reported from this taxon, ten other compounds viz:nitidine, dihydronitidine, 9-methoxychelerthrine, gamma-fagarine, skimmianine, arctigenin methylether, savinin and a mixture of campesterol, beta-sitosterol and stigmasterol. The implications of the present results for the taxonomic position of ZANTHOXYLUM TESSMANNII is discussed.

Kalaic acid, a new ursane-type saponin from Musanga cecropioides.

Six pentacyclic triterpenes were isolated from the methylated stembark polar extracts of Musanga cecropioides. One of them, methyl kalaate, is a new saponin. The known compounds were methyl ursolate, methyl oleanolate, methyl 2alpha-hydroxyursolate, methyl 2alpha-hydroxyoleanolate, and methyl pomolate. Their structures have been elucidated from 2D-NMR spectroscopic data. A complete (1)H- and (13)C-NMR spectral assignment of methyl pomolate as well as those of the new saponin have been achieved from 2D-COSY.

Myrianthiphyllin, The First Lignan Cinnamate from Myrianthus arboreus.

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.

Further Triterpenoids of Musanga cecropioides: The Structure of Cecropic Acid.

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.

Quinovic acid glycosides from Mitragyna stipulosa--first examples of natural inhibitors of snake venom phosphodiesterase I.

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.

Calodenin C: a new guibourtinidol-(4alpha-->8)-afzelechin from Ochna calodendron.

A new dimeric proanthocyanidin, calodenin C [guibourtinidol-(4alpha-->8)-afzelechin], was isolated from the stem bark of Ochna calodendron and its structure determined on the basis of chemical studies and spectroscopic data, including HMBC and ROESY experiments.

New antioxidant and antimicrobial ellagic acid derivatives from Pteleopsis hylodendron.

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.