Phytochemical analysis with free radical scavenging, nitric oxide inhibition and antiproliferative activity of Sarcocephalus pobeguinii extracts

Abstract Background Free radicals have been implicated in the pathogenesis of diverse metabolic disorders including cancer. Therefore, fighting against free radicals has become an important strategy in the prevention or treatment of such diseases, in addition to direct or indirect anticancer chemotherapy. Sarcocephalus pobeguinii has been used traditionally to treat various diseases in which excess production of free radicals is implicated, warranting investigation of its free radical scavenging, anticancer and anti-inflammatory activity. Methods In the present study, extracts from leaves, fruits, roots and bark of Sarcocephalus pobeguinii were evaluated on four human cancer cell lines (MCF-7, HeLa, Caco-2 and A549 cells) and a non-cancerous cell line for their antiproliferative potential. The cells were incubated with the plant extracts for 48 h at 37 °C in a 5% CO2 humidified environment and their cytotoxic effect was determined using the tetrazolium-based colorimetric (MTT) assay. The radical inhibition was determined using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and the 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging techniques. The nitric oxide inhibitory activity was determined using LPS-activated RAW 264.7 macrophages. The correlation between radical scavenging capacity and antiproliferative activity was also analysed. Results The extract from leaves of Sarcocephalus pobeguinii (LSP) exhibited the highest cytotoxic effect on all four of the human cancer cell lines but with some cytotoxicity to the normal Vero cells. However, the LSP extract had the best selectivity index, ranging from 3.15 to 18.28. Also, antioxidant and anti-inflammatory assays indicated that the LSP extract had the highest radical scavenging capacity of all the extracts. A positive linear correlation was found between free radical scavenging ability and antiproliferative activity against the four cancer cell lines, with the highest correlation factor (R2 = 0.9914) obtained between DPPH inhibition and antiproliferative activity against A549 cells. Conclusions The high selectivity index of the Sarcocephalus pobeguinii leaf extract indicates the potential of using this extract in cancer therapy. Furthermore, the positive correlation between free radical scavenging and antiproliferative activity suggests that the radical scavenging capacity of extracts may contribute to a prediction of their anticancer property

Crystal structure of limonoid TS3, isolated from Trichilia rubescens

The title limonoid compound, C26H28O5·0.5H2O (TS3) [systematic name: (3aS,3bS,4aS,5aS,6S,7aR,8aR,8bS,11aR)-6-(furan-3-yl)-3a,5a,8b,11a-tetramethyl-3a,4a,5,5a,6,7,7a,8b,11,11a-decahydrooxireno[2′,3′:4b,5]oxireno[2′′,3′′:2′,3′]cyclopenta[1′,2′:7,8]phenanthro[10,1-bc]furan-3(3aH)-one hemihydrate], crystallizes with two independent molecules (1 and 2) in the asymmetric unit and one water molecule. TS3 is composed of three six-membered rings (A, C and D), three five-membered rings (B, E and F) and two epoxide rings. A group of five fused rings (A–E) is bonded to a furan ring (F) with a Csp3—Csp2 bond [1.500 (3) Å in molecule 1 and 1.499 (3) Å in molecule 2]. The absolute structures of the molecules in the crystal were determined by resonant scattering; Flack parameter = 0.05 (5). In the crystal, the individual molecules stack in columns along the b-axis direction. The water molecule bridges molecules 1 and 2 via Owater—H...O and C—H...Owater hydrogen bonds. Together with further C—H...O hydrogen bonds, linking molecules 1 and 2, the columns are linked to form slabs parallel to the ab plane. Within each column, molecules are also linked via C—H...π interactions involving the five-membered furan (F) rings

Rubescins I and J, further limonoid derivatives from the stem bark of <i>Trichilia rubescens</i> (Meliaceae)

<p>Two new tetranorterpenoid derivatives named rubescins I (<b>1</b>) and J (<b>2</b>), were isolated along with six known compounds including rubescin D (<b>3</b>), lichexanthone (<b>4</b>), scopoletin (<b>5</b>), scopoletin <i>O</i>-glycoside (<b>6</b>), <i>β</i>-sitosterol (<b>7</b>) and stigmasterol (<b>8</b>) from the stem bark of <i>Trichilia rubescens</i> (Meliaceae). The structures of the compounds were determined by means of MS, different NMR and by comparison with related data reported in the literature.</p

The Limonoids TS3 and Rubescin E Induce Apoptosis in Human Hepatoma Cell Lines and Interfere with NF-κB Signaling.

Hepatocellular carcinoma (HCC) is extremely resistant towards pharmacological therapy. To date, the multi-kinase inhibitor Sorafenib is the only available therapeutic agent with the potential to prolong patient survival. Using the human hepatoma cell lines HepG2 and Huh7, we analyzed anti-cancer activities of 6 purified havanensin type limonoids isolated from the traditional African medicinal plant Trichilia rubescens Oliv. Our results show that two of the compounds, TR4 (TS3) and TR9 (Rubescin E) reduced hepatoma cell viability, but not primary hepatocyte viability, at TC50s of 5 to 10 μM. These were significantly lower than the TC50s for Sorafenib, the histone deacetylase inhibitor SAHA or 5-Fluoruracil. In comparison, TR3 (Rubescin D), a limonoid isolated in parallel and structurally highly similar to TR4 and TR9, did not interfere with hepatoma cell viability. Both, TR4 and TR9, but not TR3, induced apoptosis in hepatoma cells and interfered with NF-κB activation. TR4 as well as TR9 significantly supported anti-cancer activities of Sorafenib. In summary, the limonoids TR4 and TR9 exhibit anti-cancer activities and support Sorafenib effects in vitro, having the potential to support future HCC therapy

Anti-inflammatory activity of benzophenone and xanthone derivatives isolated from Garcinia (Clusiaceae) species

Dzoyem JP, Lannang AM, Fouotsa H, et al. Anti-inflammatory activity of benzophenone and xanthone derivatives isolated from Garcinia (Clusiaceae) species. Phytochemistry Letters. 2015;14:153-158.Species of the genus Garcinia have been the source of many benzophenone and xanthone derivatives. Recent data regarding potent biological properties of natural compounds in Garcinia species led us to investigate the in vitro anti-inflammatory effect of three known xanthones, lichexanthone (1), 1,3,6,7-tetrahydroxyxanthone (2), 1,3,5,6-tetrahydroxyxanthone (3), two new xanthones 1-hydroxy-3,6,7-tri-O, O, O-triprenylxanthone (4), 1,6-dihydroxy-3,7-di-O, O-diprenylxanthone (5) and two benzophenones isoxanthochymol (6), guttiferone E (7), isolated from Garcinia nobilis and Garcinia punctata. The Griess assay was used for the measurement of nitric oxide (NO) production in RAW264.7 macrophages and the ferrous oxidation-xylenol orange assay was used to determine the 15-lipoxygenase (15-LOX) inhibitory activity. All the compounds had inhibitory effect on 15-LOX activity to different extents. Compound (7) had the highest anti-LOX activity with an IC50 value of 43.05 mu g/mL. At the highest studied concentration (25 mg/mL), compound (4) had the most potent inhibitory activity against NO release with a% of inhibition of 95.42% and less cytotoxic effect on RAW264.7 cells (% of cell viability of 81.40). The results presented here suggest that 1,3,5,6-tetrahydroxyxanthone (3) and guttiferone E (7) are promising inhibitors of NO production and 15-LOX activity. Further studies should be considered in order to elucidate the mechanism by which these compounds exert their inhibitory activities. (C) 2015 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved

Antimycobacterial cycloartane derivatives from the roots of Trichilia welwistchii C. DC (Meliaceae).

Chemical investigation of the roots of yielded a cycloartane type terpenoid 28,29-bis-norcycloart-24-en-3 ,4 ,6 -triol ( ), isolated as pure compound for the first time, three coumarins and three sterols. New cycloartane derivatives ( ) and ( + ) were obtained by hemi-synthetic reaction of compound . The structures of – were established by spectroscopic methods including 1D and 2D-NMR analysis, HR-EIMS, chemical transformations and by comparison of these data with those of related compounds. Evaluated for their antimycobacterial potential, compound and + were determined to show significant activities against MIC values of 6.25 μg mL while compound displayed weak activity showing MIC &gt; 100 μg mL . Compounds – displayed moderate activity with MIC values range from 12.5 to 50 μg mL

A new xanthone derivative from twigs of Garcinia nobilis

Fouotsa H, Tatsimo SJN, Neumann B, et al. A new xanthone derivative from twigs of Garcinia nobilis. Natural Product Research. 2014;28(14):1030-1036.Phytochemical investigation of the twigs of Garcinia nobilis led to the isolation of a new xanthone, named l-hydroxy-2,5-dimethoxyxanthone (1), together with 15 known compounds (2-16). The structures of the new and known compounds were established by means of spectroscopic methods and by comparison with previously reported data. The structure of compound 1 was confirmed by X-ray diffraction data. Compounds 1-16 were tested for their cytotoxic activity against human cervix carcinoma cell line KB-3-1. Compounds 5 and 11 showed moderate activity while others showed weak biological activity in these cytotoxicity assays. Compounds 4 and 9 were found to be inactive