Phytochemical Screening and in vitro Anticancer Activity of Some Medicinal Plants Grown in the Kingdom of Saudi Arabia / Cribado Fitoquímico y Actividad Anticancerígena in vitro de Algunas Plantas Medicinales Cultivadas en el Reino de Arabia Saudita

SUMMARY: This study evaluated the phytochemical screening, antioxidant capacity, and in vitro anticancer activities of four plants namely, Gypsophila capillaris, Anabasis lachnantha, Haloxylon salicornicum, and Horwoodia dicksoniae which belong to four different families: Caryophyllaceae, Amaranthaceae, Chenopodiaceae, Brassicaceae, respectively. The total phenolics, anthocyanins, saponins, total antioxidant capacity (TAC), and DPPH assays were determined by spectrophotometer. In vitro anticancer activity was assessed using two human cancer cell lines; hepatocellular carcinoma (HepG-2) and breast adenocarcinoma (MCF-7) to estimate the inhibition concentration 50 % (IC50). The results showed that H. dicksoniae has the highest concentrations of phenolics and saponins, while H. salicornicum has the highest DPPH. The highest concentration of TAC was found in G. capillaries. Among the tested extracts, G. capillaries and H. salicornicum have the potential activity against MCF-7 and HepG-2 cell lines in vitro. The content of polyphenols in G. capillaries was profiled by high-performance liquid chromatography (HPLC). The highest concentration among the phenolic compounds was chlorogenic (60.8 µg/ml) while the highest concentration among the flavonoid compounds was hesperidin (1444.92 µg/ml). In summary, G. capillaries and H. salicornicum extracts have potent anticancer activity against HepG-2 and MCF-7 cell lines.

Este estudio evaluó la detección fitoquímica, la capacidad antioxidante y las actividades anticancerígenas in vitro de cuatro plantas, Gypsophila capillaris, Anabasis lachnantha, Haloxylon salicornicum y Horwoodia dicksoniae, que pertenecen a cuatro familias diferentes: Caryophyllaceae, Amaranthaceae, Chenopodiaceae y Brassicaceae, respectivamente. Los ensayos de fenólicos totales, antocianinas, saponinas, capacidad antioxidante total (TAC) y DPPH se determinaron mediante espectrofotómetro. La actividad anticancerígena in vitro se evaluó utilizando dos líneas celulares de cáncer humano; carcinoma hepatocelular (HepG-2) y adenocarcinoma de mama (MCF- 7) para estimar la concentración de inhibición del 50 % (IC50). Los resultados indicaron que H. dicksoniae tiene las concentraciones más altas de fenólicos y saponinas, mientras que H. salicornicum tiene el DPPH más alto. La mayor concentración de TAC se encontró en G. capillaries. Entre los extractos probados, G. capillaries y H. salicornicum tienen actividad potencial contra líneas celulares MCF-7 y HepG-2 in vitro. El contenido de polifenoles en G. capillaries se perfiló mediante cromatografía líquida de alta resolución (HPLC). La concentración más alta entre los compuestos fenólicos fue clorogénica (60,8 µg/ml), mientras que la concentración más alta entre los compuestos flavonoides fue la hesperidina (1444,92 µg/ml). En resumen, los extractos de Gypsophila capillaris y H. salicornicum tienen una potente actividad anticancerígena contra las líneas celulares HepG-2 y MCF-7.

Tentative Characterization of Polyphenolic Compounds in the Male Flowers of Phoenix dactylifera by Liquid Chromatography Coupled with Mass Spectrometry and DFT.

Phoenix dacylifera is an ancient palm species rich in (poly)phenols. These phenolic compounds were tentatively identified by using liquid chromatography coupled with ion spray mass spectrometry in tandem mode (LC/MS/MS) with negative ion detection. Negative identification of the compounds was based on their retention times and mass spectra in full scan mode (MS), and in different MS/MS modes. For the first time, complete hypothesis, and routs for both p-coumaroylshikimic acids (CoSA) and caffeoylshikimic acids (CSA) were suggested and confirmed by Density Fonctional Theory (DFT) study. Notably, of the 53 compounds characterized, 19 hydroxycinnamates derivatives were tentativelycharacterized in male flowers of date palm and 15 of them were recorded for the first time. In addition, five organic acids, six B-type proanthocyanidins, two anthocyanidin and 21 flavonoid derivatives have been tentatively characterized. Identification of B-type proanthocyanidins were based on the diagnostic ions resulting from heterocyclic ring fission (HRF) and retro-Diels-Alder (RDA) reaction of flavan-3-ol provided information on the hydroxylation pattern and the type of inter-flavan bond proanthocyanidins. The sequence of proanthocyanidins was detected through ions extracted from quinone methide (QM) cleavage of the inter-flavan bond.

Comparison of biological activity of phenolic fraction from roots of Alhagi maurorum with properties of commercial phenolic extracts and resveratrol.

Phenolic compounds have different biological properties, including antioxidative activities, but they may also be prooxidants. The effect of phenolic fraction from roots of Alhagi maurorum on oxidative protein/lipid damages (determined by such parameters as levels of protein thiol groups and the concentration of thiobarbituric acid reactive species--TBARS) in human blood platelets and human plasma after treatment with hydrogen peroxide--H2O2 (which is the strong biologic oxidant and inflammatory mediator) was studied in vitro. We also studied the effect of A. maurorum extract on blood platelet activation corresponding to thrombin-induced arachidonic acid pathway. Moreover, the present work was designed to study the effect of A. maurorum extract on selected physiological function of blood platelets--adhesion of blood platelets to collagen in vitro. The action of phenolic fraction from A. maurorum was compared with the selected commercial phenolic extracts: extract from berries of Aronia melanocarpa (Aronox®), extract from bark of Yucca schidigera and monomeric polyphenol-resveratrol (3,4',5-trihydroxystilbene). Exposure of blood platelets or plasma to H2O2 resulted in a decrease of the level of thiol groups in proteins, and an increase of TBARS. In the presence of phenolic fraction from A. maurorum (0.5-50 µg/ml), a reduction of thiol groups oxidation together with the decrease of autoperoxidation of lipids and lipid peroxidation caused by H2O2 or thrombin was observed. The inhibitory, concentration-dependent effects of A. maurorum extract on adhesion of thrombin-activated platelets to collagen were also found. The phenolic fraction from A. maurorum acts as an antioxidant and can be useful as the natural factor protecting against diseases associated with oxidative stress. Tested fraction from A. maurorum has more effective antioxidative activity and antiplatelet properties than aronia extract or other commercial extract, however differences between their actions are not statistically significant.

Extracts from Tribulus species may modulate platelet adhesion by interfering with arachidonic acid metabolism.

The present work was designed to study the effects of crude extracts from Tribulus pterocarpus, T. pentandrus and T. parvispinus on selected biological functions of human blood platelets in vitro. Platelet suspensions were pre-incubated with extracts from aerial parts of T. pterocarpus, T. pentandrus and T. parvispinus, at the final concentrations of 0.5, 5 and 50 µg/ml. Then, for platelet activation thrombin, was used. The effects of crude extracts from T. pterocarpus, T. pentandrus and T. parvispinus on adhesion of blood platelets to collagen were determined by method according to Tuszynski and Murphy. Arachidonic acid metabolism was measured by the level of thiobarbituric acid reactive substances (TBARS). In these studies we also compared the action of tested crude plant extracts with the effects of the polyphenolic fraction isolated from aerial parts of T. pterocarpus, which has antiplatelet and antioxidative properties. The performed assays demonstrated that the tested crude extract from T. pterocarpus and the phenolic fraction from T. pterocarpus might influence the platelet functions in vitro. The inhibitory, concentration-dependent effects of this tested extract and its phenolic fraction on adhesion of resting platelets and thrombin - stimulated platelets to collagen was found. We also observed that the crude extract from T. pterocarpus, like the polyphenolic fraction from T. pterocarpus reduced TBARS production in blood platelets. In the comparative studies, the tested crude extract from T. pterocarpus was not found to be more effective antiplatelet factor, than the polyphenolic fraction from this plant. The results obtained suggest that T. pterocarpus may be a promising source of natural compounds, valuable in the prevention of the enhanced activity of blood platelets in numerous cardiovascular diseases.

Profiles analysis of proanthocyanidins in the argun nut (Medemia argun--an ancient Egyptian palm) by LC-ESI-MS/MS.

Medemia argun is an ancient palm rich in proanthocyanidins (PACs). These polyphenolic compounds are widely distributed in plants and are an integral part of the human diet. A sensitive high-performance liquid chromatography and electrospray ionization mass spectrometry (HPLC-ESI-MS) method in the negative ion mode for sequencing these ubiquitous and highly beneficial antioxidants is described in order to profile different PACs in M. argun nuts. The analytical protocol based on tandem mass spectrometry was used to sequence dimers, trimers, tetramers and pentamers with different A-type, B-type and A/B-type linkages. Diagnostic ions resulting from heterocyclic ring fission and retro-Diels-Alder reaction of flavan-3-ol provided information on the hydroxylation pattern and the type of interflavan bond. The sequences were discovered through ions derived from quinone methide cleavage of the interflavan bond. The identification of PACs linkages through LC-MS(n) eliminates a number of tedious separation steps. The method was successfully applied to give a view of PAC profile in M. argun nuts. M. argun nuts contained 636.88 mg/g PACs (as equivalent of (þ)-catechin). The data obtained in our research show that M. argun is a rich source of hydrolyzable PACs.

Unusual fernane and gammacerane glycosides from the aerial parts of Spergula fallax.

The aerial parts of Spergula fallax afforded four glycosides (1-4) based on two new triterpene aglycones (1a and 2a), along with the known hopane glycoside succulentoside A. Compound 1 was identified as belonging to the fernane class, unusual migrated hopane triterpenoids, mainly isolated from ferns and only rarely from higher plants. Compounds 2-4 were assigned as gammacerane glycosides, having as aglycone a hydroxylated derivative of tetrahymanol. The structures of the isolated compounds 1-4 and their aglycones 1a and 2a obtained by acid hydrolysis were elucidated by spectroscopic data interpretation. The growth inhibitory activity of the isolated compounds and their aglycones was evaluated against the HeLa and DLD-1 cancer cell lines.

Protective action of proanthocyanidin fraction from Medemia argun nuts against oxidative/nitrative damages of blood platelet and plasma components.

The oxidative/nitrative stress induced by different factors plays an important role in the pathogenesis of various disorders, including cardiovascular diseases and cancer. Proanthocyanidins have antioxidative properties and may protect biomolecules (lipids, DNA, and proteins) exposed to reactive oxygen and nitrogen species, including peroxynitrite (ONOO(-)). The effects of proanthocyanidin fraction from Medemia argun nuts on oxidative/nitrative protein damages (determined by such parameters as level of thiol groups, carbonyl groups, and nitrotyrosine residues) and on the amount of glutathione (as an important component of redox status; using HPLC) in human blood platelets and plasma after treatment with peroxynitrite were studied in vitro. The preincubation of blood platelets and plasma with proanthocyanidin fraction from M. argun nuts (0.5-50 µg/ml) reduced the formation of 3-nitrotyrosine, diminished oxidation of thiol groups, and decreased the level of carbonyl groups in proteins caused by 100 µM peroxynitrite. An action of tested plant fraction and ONOO(-) evoked a significant increase of GSH in platelets and plasma in comparison with platelets and plasma treated with ONOO(-) only. The proanthocyanidin fraction from M. argun nuts can be useful as a protecting factor against oxidative/nitrative stress associated with different diseases (cancer, cardiovascular, and neurodegenerative diseases) and proanthocyanidins of M. argun nuts may be promising antioxidants.

Evaluation of polyphenolic fraction isolated from aerial parts of Tribulus pterocarpus on biological properties of blood platelets in vitro.

The antiplatelet and antioxidative activity of polyphenolic fraction isolated from aerial parts of Tribulus pterocarpus in blood platelets stimulated by thrombin was studied. Thrombin as a strong physiological agonist induces the enzymatic peroxidation of endogenous arachidonic acid, the formation of different reactive oxygen species, including superoxide anion radicals ([Formula: see text](·)) and the platelet aggregation. Therefore, the aim of our study was to assess if the polyphenolic fraction from aerial parts of T. pterocarpus may change the biological properties of blood platelets activated by thrombin. We used cytochrome c reduction method to test the ability of this fraction to change [Formula: see text](·) generation in platelets. Arachidonic acid metabolism was measured by the level of thiobarbituric acid reactive substances (TBARS) and by the production of 8-epi-prostaglandin (8-EPI) F(2). Moreover, we determined the effects of the fraction on blood platelet aggregation induced by thrombin. We observed that the polyphenolic fraction from T. pterocarpus reduced [Formula: see text](·), 8-EPI and TBARS production in these cells. The ability of the fraction to decrease the [Formula: see text](·) generation in blood platelets supports the importance of free radicals in platelet functions, including aggregation process. This study may suggest that the tested plant fraction might be a good candidate for protecting blood platelets against changes of their biological functions, which may be associated with the pathogenesis of different cardiovascular disorders.

Strong antioxidant phenolics from Acacia nilotica: profiling by ESI-MS and qualitative-quantitative determination by LC-ESI-MS.

Acacia nilotica (L.) Del. syn is a species rich in polyphenolic constituents, in which catechins are hypothesized to possess antioxidant properties and to play a role in the anti-inflammatory activity of several plants. Due to the complexity of catechin derivatives, the investigation of this class of natural compounds has been limited by difficulties in their separation. In this paper, rationalization of the phenolics occurring in the 80% EtOH extract of Acacia nilotica pods, on the basis of ESI-MS and ESI-MS/MS profiles, has been proposed. Additionally, an LC-ESI-MS qualitative study has been performed by using a C18 polar endcapped stationary phase. The fragmentation pattern obtained evidenced the presence in A. nilotica pods of galloylated catechin- and gallocatechin derivatives along with galloylated glucose derivatives. The structures were confirmed by NMR, after isolation of the pure compounds. In addition, the radical scavenging activities of extracts and pure compounds were investigated, by using the TEAC assay. Furthermore quantitative analyses were performed by LC-ESI-MS/MS, confirming the interest of this species as a rich source of very strong antioxidant principles.

Sulfated triterpene derivatives from Fagonia arabica.

Two new sulfated triterpenes (1, 6) and four new sulfated triterpene glycosides (2-5) have been isolated from the aerial parts of Fagonia arabica. Their structures were established by spectroscopic data analysis. Compounds 1/2 and 3/4 are sulfated derivatives of the rare sapogenins 3beta,27-dihydroxyolean-12-en-28-oic acid and 3beta,27-dihydroxyurs-12-en-28-oic acid, respectively. Compound 5 is an unusual disulfated oleanene derivative characterized by the occurrence of a 13,18-double bond, while compound 6 is the first reported naturally occurring saturated and sulfated pentacyclic triterpene of the taraxastane series with a C-20,28 lactone unit.

Cardenolide glycosides from Pergularia tomentosa and their proapoptotic activity in Kaposi's sarcoma cells.

Continuing our investigations on plants belonging to the Asclepiadaceae family, three new cardenolide glycosides, 3'-O-beta-D-glucopyranosylcalactin (1), 12-dehydroxyghalakinoside (2), and 6'-dehydroxyghalakinoside (3), along with the known ghalakinoside (4) and calactin (5), were isolated from the roots of Pergularia tomentosa. The structures of these compounds were elucidated by extensive spectroscopic methods including 1D- and 2D-NMR experiments as well as ESIMS analysis. The isolated cardenolides caused apoptotic cell death of Kaposi's sarcoma cells.

14,15-secopregnane derivatives from the leaves of Solenostemma argel.

Five new 14,15-secopregnane derivatives, named argelosides K-O (1-5), have been isolated from Solenostemma argel leaves. Their structures were established by a detailed spectroscopic analysis. In particular, argeloside N (1) showed in the sugar portion an unusual 3-O-methyl-2,6-dideoxyhexopyranose unit characterized by the occurrence of a Delta3 double bond, and argeloside O (5) displayed an unusual moiety linked to position 3 probably derived by the oxidation of a 3-O-methyl-2,6-dideoxyhexopyranose unit. The propensity of compounds 2, 3, and 5 and argeloside F (6) to inhibit TNF-alpha release by LPS-stimulated RAW 264.7 mouse cells was evaluated.

Cytotoxic furostanol saponins and a megastigmane glucoside from tribulus parvispinus.

Two new furostanol saponins, (25R)-26-O-beta-D-glucopyranosyl-5alpha-furostan-2alpha,3beta,22alpha,26-tetraol 3-O-{beta-D-galactopyranosyl-(1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside} (1) and (25R)-26-O-beta-D-glucopyranosyl-5alpha-furostan-3beta,22alpha,26-triol 3-O-{beta-D-galactopyranosyl-(1-->2)-O-[beta-D-xylopyranosyl-(1-->3)]-O-beta-D-glucopyranosyl-(1-->4)-beta-D-galactopyranoside} (2), and their O-methyl derivatives (3 and 4), and a new megastigmane glucoside, (6S,7E,9xi)-6,9,10-trihydroxy-4,7-megastigmadien-3-one 10-O-beta-D-glucopyranoside (6), along with one known spirostanol saponin, gitonin (5), and four known megastigmane glucosides were isolated from the aerial parts of Tribulus parvispinus. Their structures were established by detailed spectroscopic analysis. The cytotoxic activities of 1-6 against U937, MCF7, and HepG2 cells were evaluated. Compounds 2 (IC(50) 0.5 microM) and 5 (IC(50) 0.1 microM) showed the highest activity against U937 cells.

Antiproliferative hopane and oleanane glycosides from the roots of Glinus lotoides.

Three new hopane saponins, lotoidosides A - C (1 - 3), and four new oleanane saponins, lotoidosides D - G (4 - 7), were isolated from the roots of Glinus lotoides L. (Molluginaceae). Their structures were determined by extensive 1D- and 2D-NMR spectroscopy and ESI-MS analysis. The antiproliferative activity of compounds 1 - 7 was evaluated using three continuous murine and human culture cell lines J774.A1, HEK-293, WEHI-164. Compounds 1 and 3 - 7 showed significant cytotoxicity against the three cancer cell lines with IC50 values ranging from 0.018 to 0.62 microM, while compound 2 exerted a weak activity only against the cell line HEK-293.

New unusual pregnane glycosides with antiproliferative activity from Solenostemma argel.

Seven new 15-keto pregnane glycosides, namely Stemmosides E--K, were isolated from Solenostemma argel. Stemmosides E--J are characterized by the occurrence of an uncommon 14 beta proton configuration while stemmosides E and F possess in addition a rare enolic function in C-16. On the other hand, stemmosides G-J display an unusual C-17 alpha side chain. Their structures were established by ESI-MS and NMR experiments. Moreover, the effect of these compounds on the VEGF-induced in Kaposi's sarcoma cell proliferation was tested. Results indicated that all the compounds reduced the cell proliferation in a dose dependent manner.