Crotofoligandrin, a new endoperoxide crotofolane-type diterpenoid from the twigs of Croton oligandrus Pierre ex. Hutch (Euphorbiaceae).

Crotofoligandrin (1), a new endoperoxide crotofolane-type diterpenoid was isolated from the dichloromethane/methanol (1:1) extract of the twigs of Croton oligandrus Pierre Ex Hutch along with thirteen known secondary metabolites including 1-nonacosanol (2), lupenone (3), friedelin (4), ß-sitosterol (5), taraxerol (6), (-)-hardwickiic acid (7), apigenin (8), acetyl aleuritolic acid (9), betulinic acid (10), fokihodgin C 3-acetate (11), D-mannitol (12), scopoletin (13) and quercetin (14). The structures of the isolated compounds were determined based on their spectroscopic data. The crude extract and the isolated compounds were assessed in vitro for their antioxidant, lipoxygenase, butyrylcholinesterase (BChE), urease and glucosidase inhibitory potentials. Compounds 1-3, and 10 displayed activities on all the performed bioassays. All the tested samples showed strong to significant antioxidant activity with compound 1 being the most potent (IC50 39.4 µM).

Echinograciolide, a new antibacterial nor-triterpenoid and other constituents from Echinops gracilis O. Hoffm. (Asteraceae).

Antibacterial resistance is a serious threat against humankind and the search for new therapeutics is needed. This study aims to investigate the antibacterial activity of extracts and compounds from Echinops gracilis O. Hoffm. Standard chromatographic and spectroscopic methods were used to isolate and characterize compounds (1-15) from the methanol extract. The extract, chromatographic fractions and compounds 1-3, 8, 11, 13 and 14 were subjected to in vitro antibacterial assays against Staphylococcus aureus ATCC25923, Salmonella Typhi ATCC6539, Klebsiella pneumoniae 22, and Salmonella Typhi 68, using broth micro-dilution method. As results, a new nor-triterpenoid (1) and fourteen known compounds (2-15) were characterized. The extract and fractions displayed moderate (128 ≤ MIC ≤ 512 µg/mL) and significant (MIC 64 µg/mL) antibacterial activities. Compounds 1 and 14 showed the best anti-staphylococcal and anti-salmonella activity (MIC 16 µg/mL), respectively. These results partially justified the antimicrobial uses of E. gracilis in traditional medicine.

Rapid Identification of Common Secondary Metabolites of Medicinal Herbs Using High-Performance Liquid Chromatography with Evaporative Light Scattering Detector in Extracts.

The discovery and identification of novel natural products of medicinal importance in the herbal medicine industry becomes a challenge. The complexity of this process can be reduced by dereplication strategies. The current study includes a method based on high-performance liquid chromatography (HPLC), using the evaporative light scattering detector (ELSD) to identify the 12 most common secondary metabolites in plant extracts. Twelve compounds including rutin, taxifolin, quercetin, apigenin, kaempferol, betulinic acid, oleanolic acid, betulin, lupeol, stigmasterol, and ß-sitosterol were analyzed simultaneously. The polarity of the compounds varied greatly from highly polar (flavonoids) to non-polar (triterpenes and sterols). This method was also tested for HPLC-DAD and HPLC-ESI-MS/MS analysis. Oleanolic acid and ursolic acid could not be separated in HPLC-ELSD analysis but were differentiated using LC-ESI-MS/MS analysis due to different fragment ions. The regression values (R2 > 0.996) showed good linearity in the range of 50-1000 µg/mL for all compounds. The range of LOD and LOQ values were 7.76-38.30 µg/mL and 23.52-116.06 µg/mL, respectively. %RSD and % trueness values of inter and intraday studies were mostly <10%. This method was applied on 10 species of medicinal plants. The dereplication strategy has the potential to facilitate and shorten the identification process of common secondary metabolites in complex plant extracts.

Crotoliganfuran, a new clerodane-type furano-diterpenoid from Croton oligandrus Pierre ex Hutch.

The phytochemical investigation of the methanol extract of the bark of Croton oligandrus Pierre ex Hutch yielded a new clerodane-type diterpenoid crotoliganfuran (1) along with ten other compounds including 12-epicrotocorylifuran (2), lupeol (3), syringic acid (4), aleuritolic acid acetate (5), aleuritolic acid (6), scopoletin (7), geddic acid (8), ß-sitosterol (9), vanilic acid (10) and stigmastane-3,6-dione (11). Their structures were established by spectroscopic means. The extract and all the isolates were screened for their inhibitory properties against butyrylcholinesterase and urease enzymes, respectively. The extract and compounds 1, 4 and 7 displayed the most potent urease inhibitory properties with IC50 values, 22.2, 26.7 and 28.5 µM, respectively. Compound 9 was the most active of all the tested compounds against butyrylcholinesterase enzyme with an IC50 value of 36.3 µM.[Formula: see text].

The chemistry and biological activities of Citrus clementina Hort. Ex Tanaka (Rutaceae), a vegetatively propagated species.

We report the chemistry and biological activities of a Cameroonian Citrus clementina Hort. Ex Tanaka, a vegetatively propagated species. The compounds isolated from this plant were determined to be the known 5-hydroxy-6,7,8,3',4'-pentamethoxyflavone (1), tangerine (3), nobilletin (4), 5,7,8,4'-tetramethoxyflavone (5), citracridone I (6), 5-hydroxynoracronycine (7), citracridone III (8), xanthyletin (10), suberosin (9), E-suberenol (11), E-methoxysuberenol (13), 6-formylumbelliferone (12), aurantiamide acetate (2), limonin (14), stigmasterol, ß-sitosterol and ß-sitosterol-3-O-ß-D-glucoside. The structures of the compounds were established on the basis of their NMR spectroscopic data and comparison with published data. Methanol leaf extract and compounds 1, 2, 4, 6, 7 and 10 were evaluated for their anti-inflammatory, antioxidant, urease and anti-diabetic effects. Compound 10 showed antioxidant activity, anti-inflammatory effect, urease activity and anti-diabetic activity with IC50 values of 47.3 µM, 33.5 µM, 25.2 µM and 33.9 µM respectively, values that were comparable to the respective positive standards.

Bioactive constituents from Manilkara obovata (Sabine & G.Don) J.H.Hemsl.

The phytochemical investigation of the methanolic extracts of roots, stem bark, leaves and twigs of Manilkara obovata has led to the isolation of one new friedelane triterpene, lacefriedelic acid or 3ß,23-dihydroxy D:A-friedooleanan-28-oic acid (1) and one new prenylated xanthone, lacexanthone or 4,7-dihydroxy-2,3,3,9,9-pentamethyl-2,2-dihydrofurano[2,3-a]pyrano[2,3-i]xanthen-13(9H)-one (2) alongside twenty-four known compounds. Compounds 1-11 are reported here for the first time from the genus Manilkara. The structures of all compounds were determined by spectroscopic analyses and X-ray crystallography. The methanolic extracts of twigs and leaves showed anti-oxidant activity of 93.2 and 91.1%, respectively, at 100 µg/mL when measured by DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate), while the twig extract displayed 86.3% at 100 µg/mL against the urease inhibition assay. Some isolated compounds (1-4, 15 and 20) showed significant to moderate anti-oxidant activity and urease inhibition assay. It is estimated that significantly active anti-oxidants and urease inhibitors metabolized by the plant may find future application in food industry.

Nephroprotective effect of ethanol extract and fractions of a sea lettuce, Ulva fasciata against cisplatin-induced kidney injury in rats.

Cisplatin is widely used in anticancer therapy, but a substantial percentage of patients who receive the therapeutic dose of cisplatin develop nephrotoxicity. Hepatotoxicity may also develop after a single dose or low repeated doses of cisplatin. Ulva fasciata is an edible seaweed, commonly known as sea lettuces have also been shown various biological activities. In this study, ethanol extract and its solvent fractions (n-hexane and chloroform) of U. fasciata were given (orally) to different groups of rats for 10 days. Injury to the kidney was induced by administrating cisplatin, intraperitoneally (i.p.) to rats at a dose of 7 mg/kg body weight (b.w.) dissolved in 1 mL saline, at 5th day of the experiment. At 10th day rats were sacrificed and kidney parameters (creatinine, urea, and blood urea nitrogen (BUN)) and electrolyte balance (Ca++, Mg++, K+, and Na+) in serum were determined, while oxidative stress markers glutathione (GSH), catalase (CAT) and malondialdehyde (MDA), and inflammatory cytokines, tumor necrosis factor (TNF α), and interleukin (IL-6) were determined in kidney tissues. Histological examination of the kidney was also performed to examine the changes in kidney tissues. Cisplatin caused adverse effects on blood parameters, antioxidants, and inflammatory markers with severe renal tubular injury in kidney tissues. Ethanol extract of U. fasciata and its fractions effectively improved these disorders and diminished the renal dysfunction. However, ethanol extract was found more effective in attenuating the adverse effect of cisplatin than its fractions. n-Hexane-soluble fraction that was subjected to GC-FID and GC-MS analysis revealed the presence of several compounds and some of them are new from this source. It could be concluded that the U. fasciata possesses nephroprotective effect and can attenuate cisplatin-induced renal dysfunction. Since U. fasciata is an edible seaweed, it may be used as a diet supplement.

Muriolide, a novel antioxidant lactone from Ranunculus muricatus.

Muriolide (1), a new aromatic lactone, has been isolated from the ethyl acetate fraction of Ranunculus muricatus. The compound was structurally characterized with the help of UV, IR, mass, 1D- and 2D-NMR data. It was tested in vitro for antioxidant and lipoxygenase inhibitory potential. Compound 1 showed good DPPH radical scavenging activity (IC50=56.9 µM), however it was moderately active against lipoxygenase enzyme (IC50=68.3 µM).

Antibacterial phloroglucinols derivatives from the leaves of Mallotus oppositifolius (Geisler) Müll. Arg. (Euphorbiaceae).

From the ethno-medicinally used leaves of Mallotus oppositifolius, four acylphloroglucinol derivatives, namely Acronyculatin SU (1-3) and Mallotojaponin D (4) were isolated along with seven known compounds (5-11). Structures were elucidated by comprehensive spectroscopic analyses and HRMS data. Absolute configurations were assigned by careful comparison of their specific optical rotation with those of closely related compounds. Compounds 1, 2, 6 and 11 demonstrated inhibitory activity against the bacterial strains E. coli, S. aureus, S. typhi, P. aeruginosa with minimum inhibitory concentration (MIC) values ranging from 3.125 to 50 µg/ml.

Flavonoids and triterpenes from Combretum fragrans with anti-inflammatory, antioxidant and antidiabetic potential.

Despite the well-documented benefits of Combretum fragrans in Cameroon, only few scientific works have been done on it. In this study we isolated eight compounds from the leaves extract of C. fragrans: velutin (1), belamcanidin (2), cirsilineol (3), cirsimaritin (4), 3ß-acetoxy-20,24-epoxy-11,25-hydroxy-dammarane (5), combretin A (6), combretin B (7) and a mixture of arjunolic acid (8a) and asiatic acid (8b). Compounds 6 and 7 presented potent anti-inflammatory, antioxidant and antidiabetic activities. Compounds 1, 3, 5 and the mixture of 8a and 8b were significantly active, and compounds 2 and 4 presented moderate activity for reactive oxygen species inhibitory and free-radical scavenging. All compounds were isolated using chromatographic techniques; their structures were elucidated by spectroscopic techniques and their spectroscopic data compared with those of the literature. Anti-inflammatory activity was evaluated via the oxidative burst assay using a luminol-amplified chemiluminescence technique, antioxidant activity by free-radical scavenging activity (DPPH) and antidiabetic activity via α-glucosidase inhibition. All of the isolated compounds (1-8) were reported to exhibit significant antioxidant activity. Compounds 1, 3, and 5-8 exhibited potent chemiluminescence inhibition effect, and only compounds 6 and 7 inhibited α-glucosidase. Thus, C. fragrans can be used as an effective natural source of anti-inflammatory, antioxidant and antidiabetic compounds.

Neomacrodione: a new degraded diterpenoid from the roots of Neoboutonia macrocalyx Beng (Euphorbiaceae).

One new degraded diterpenoid 3,6-dihydroxy-1,7-dimethyl-9,10-phenantroquinone (neomacrodione) (1) together seven known compounds were isolated from the roots of Neoboutonia macrocalyx (Euphorbiaceae). The structures of the compounds were established based on their NMR and mass spectrometric data in conjunction with those previously reported in the literature. Compound (1) displayed moderate antibacterial activities.

Immunomodulatory activities of isolated compounds from the root-bark of Cussonia arborea.

CONTEXT: Cussonia arborea Hochst. ex A. Rich (Araliaceae) is a folk medicine used to treat various diseases. However, there is no report of the root phytochemistry. OBJECTIVE: This study isolates and identifies the immunomodulatory compounds from root-bark of C. arborea. MATERIALS AND METHODS: The methanol extract (18 g) was subjected to repeated column chromatography resulting in isolation of five compounds (1-5). Structure determination was achieved by analysis of their 1 D and 2 D NMR, and mass spectroscopy. The compounds (100-1.0 µg/mL) were examined immunomodulatory for effect on production of reactive oxygen species (ROS) from whole blood phagocytes and on proliferation of T-cells. The compounds cytotoxicity (100-1.0 µg/mL) was evaluated on NIH-3T3 normal fibroblast cells. RESULTS: Three pentacyclic triterpenoids [3, 23-dihydroxy-12-oleanen-28-oic acid (1), 3ß-hydroxylolean-12-en-28-oic (2) and 23-hydoxy-oxo-urs-12-en-28-oic acid (5)], two phytosterols: [stigmasterol (3)] and [3-O-ß-d-glucopyranosyl stigmasterol (4)] were all isolated from the methanol soluble extract. All the tested compounds (1-4) were found to be nontoxic on NIH-3T3 cells. Compound 1 and 2 moderately inhibited the production of ROS (IC50 = 24.4 ± 4.3 and 37.5 ± 0.1 µg/mL, respectively) whereas compound 2 exhibited the highest inhibitory effect (IC50 = 12.6 ± 0.4 µg/mL) on proliferation of phytoheamagglutinin (PHA) activated T-cells. CONCLUSIONS: The isolated compounds (1-5) are reported for the first time from this species. In addition, compound 2 with suppressive potential on production of intracellular ROS and proliferation of T-cells could be of immense value in control of autoimmune diseases as well as in immune compromised patients.

Crystal structure and Hirshfeld surface analysis of 3-oxours-12-ene-27a,28-dioic acid (quafrinoic acid).

The title compound, C30H44O5, is a penta-cyclic triterpene isolated from the Cameroonian medicinal plant Nauclea Pobeguinii and known as quafrinoic acid. The mol-ecule is composed of five fused six-membered rings, four of which adopt a chair conformation and one a half-chair conformation. Intra-molecular C-H⋯O hydrogen-bond inter-actions exist, which generate S6 and S8 rings. In the crystal, mol-ecules are linked by pairs of O-H⋯O hydrogen bonds, linking R22(8) rings into chains running parallel to the a axis; these chains are further connected into layers parallel to the ab plane by C-H⋯O hydrogen bonds. The Hirshfeld surface analysis of the crystal structure indicates that the most important contributions for the crystal packing are from H⋯H (79.4%) and O⋯H (20.4%) inter-actions.

A new glycosidic antioxidant from Ranunculus muricatus L. (Ranunculaceae) exhibited lipoxygenasae and xanthine oxidase inhibition properties.

Phytochemical investigation of Ranunculus muricatus L. (Ranunculaceae) led to the isolation of a new metabolite named as ranuncoside from the ethyl acetate fraction of the plant. Structure of the novel compound was elucidated through detailed spectroscopic analyses, using UV, IR, 1H, 13C NMR and 2D NMR in combination with EIMS and HR EI-MS techniques. The compound was evaluated for antioxidant activity using the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging assay. Its inhibitory potential was tested against lipoxygenase and xanthine oxidase enzymes. Ranuncoside potently scavenged the DPPH free radicals (IC50 = 56.7 ± 0.43 µM) and strongly inhibited the activities of lipoxygenase (IC50 = 63.9 ± 0.17 µM) and xanthine oxidase (IC50 = 43.3 ± 0.22 µM).

In vitro anti-oxidant potential of new metabolites from Hypericum oblongifolium (Guttiferae).

Phytochemical investigations on Hypericum oblongifolium led to the isolation of a flavone named folicitin (1) and a bicyclic conjugated lactone, folenolide (2) from the ethyl acetate fraction of methanolic extract. Both metabolites were characterised as new compounds based on detailed spectroscopic analyses. In vitro anti-oxidant potential of both the compounds was evaluated by the DPPH radical scavenging assay. Compound 1 exhibited significant antioxidant activity while compound 2 was found inactive.

Two new prenylflavanones from Erythrina sigmoidea.

Two new prenylflavanones named sigmone and sigmotriol have been isolated from the stem bark of Erythrina sigmoidea along with two known constituents 8-(3"-methylbut-2"-enyl)-7,3',4'-trihydroxyflavanone and 7,3',4'-trihydroxyflavanone. Their structures were elucidated by spectroscopic methods.

Two new rotenoids from Boerhavia repens.

Two new rotenoids, boerharotenoids A (1) and B (2), and four known compounds, boeravinone (3), 5,7,3'-trihydroxycoumaronochromone (4), boeravinone F (5), and eupalitin-3-O-beta-D-galactopyranoside (6), have been isolated from Boerhavia repens and their structures established by spectroscopic (1D and 2D NMR) and mass spectrometric comparison with literature values.

Flavonoids from Erythrina vogelii (Fabaceae) of Cameroon.

A new flavone, vogeol, and a new isoflavone, vogliiol, have been isolated from Erythrina vogelii, a Cameroonian medicinal plant, along with seven known constituents (salvigenin, carpachromene, euchrenone b10, scandenone, 5,4'-dihydroxy-8-(3"-methylbut-2"-enyl)-2'''-(4'''-hydroxy-4'''-methylethyl)-furano-[4''',5''':6,7] isoflavone, erythrivarone C, and 5,7,4'-trihydroxy-6-[3"-methylbut-3"-enyl]-flavone). Their structures were elucidated by spectroscopic methods.

Formadienoate-A and B: two new long chained feruloyl esters from Clerodendrum formicarum (Lamiaceae) of Cameroon.

The ethanol extract of the leaves of Clerodendrum formicarum Gürke, a Lameacious plant of Cameroon, afforded two new long-chained esters named formadienoate-A (1) and B (2) along with two known constituents which have been obtained for the first time from C. formicarum. They include: hexacosyl-(E)-ferulate (3) and 26-hydroxyhexacosyl-(E)-ferulate (4). Structures of all the isolated constituents have been elucidated with the aid of 1D and 2D NMR spectroscopic techniques.

Antimicrobial pentacyclic triterpenoids from Terminalia superba.

Antibacterial bioassay-guided fractionation of the methanol extract of the stem bark of Terminalia superba led to the isolation of four new triterpene glucosides (1-4) which were characterized as 2 alpha,3 beta-dihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (1), 2 alpha,3 beta, 21 beta-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (2), 2 alpha,3 beta, 29-trihydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (3) and 2 alpha,3 beta,23,27-tetrahydroxyolean-12-en-28-oic acid 28-O-beta-D-glucopyranoside (4) together with the known triterpene 2 alpha,3 beta,23-trihydroxyolean-12-en-28-oic acid (5). Structures were established by spectroscopic methods including one- and two-dimensional NMR, EI-MS and HR-EI-MS. The antibacterial activity of 1-5 was also investigated against two gram-positive (Bacillus subtilis, Staphylococcus aureus), and four gram-negative (Escherichia coli, Shigella flexenari, Pseudomonas aeruginosa, Salmonella typhi) bacterial strains.