Effect of simulated gastrointestinal conditions and epithelial transport on extracts of green tea and sage

Few in vitro screening studies on the biological activities of plant extracts that are intended for oral administration consider the effect of the gastrointestinal system. This study investigated this aspect on extracts of Camellia sinensis (green tea) and Salvia officinalis (sage) using antimicrobial activity as a model for demonstration. Both the crude extracts and their products after exposure to simulated gastric fluid (SGF) as well as simulated intestinal fluid (SIF) were screened for antimicrobial activity. The chromatographic profiles of the crude plant extracts and their SGF as well as SIF products were recorded and compared qualitatively by means of high performance liquid chromatography coupled to mass spectrometry. The effect of epithelial transport on the crude plant extracts was determined by applying them to an in vitro intestinal epithelial model (Caco-2). The crude extracts for both plants exhibited reduced antimicrobial activity after exposure to SGF, while no antimicrobial activity was detected after exposure to SIF. These results suggested chemical modification or degradation of the antimicrobial compounds when exposed to gastrointestinal conditions. This was confirmed by a reduction of the peak areas on the LC–UV–MS chromatograms. From the chromatographic profiles obtained during the transport study, it is evident that some compounds in the crude plant extracts were either not transported across the cell monolayer or they were metabolised during passage through the cells. It can be deduced that the gastrointestinal environment and epithelial transport process can dramatically affect the chromatographic profiles and biological activity of orally ingested natural products.     

Evaluation of bioactive compounds,free radical scavenging and anticancer activities of bulb extracts of Boophone disticha from Eastern Cape Province,South Africa

Boophone disticha (B. disticha) is a bulbous tropical and subtropical flowering plant widespread in Africa, which is frequently used to treat several human ailments. Until the present, there is no scientific validation on the biological activity of this plant from the Eastern Cape Province of South Africa and as a result, this study aimed to assess the bioactive compounds, free radicals scavenging and anticancer potentials of crude bulb extracts (chloroform, acetone, and ethanol) of Boophone disticha obtained from this geographical location. Standard biochemical techniques and Gas-chromatography mass spectrometry (GCMS) analysis were used to pinpoint the bioactive compounds in the crude extracts sequel to their antioxidant potentials against radicals such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), hydrogen peroxide and nitric oxide as well as their ferric ion reducing power. In addition, their cytotoxicity effects against Human cervix adenocarcinoma (HeLa) cells were assessed as an in vitro model for anticancer. The phytochemical evaluation of the crude extracts showed the presence of phenolics, flavonoids, and alkaloids. GCMS profiles confirmed the presence of some bioactive compounds in the crude extracts of B. disticha that could be responsible for their biological activities. The plant extracts possessed considerable antioxidant activity and exhibited dose-dependent radicals’ inhibition from all assays carried out. Furthermore, the cytotoxicity effects against HeLa cells recorded inhibition concentration (IC₅₀) of 1.5, 1.6, and 1.9 µg/mL for acetone, chloroform, and ethanolic extracts of B. disticha, respectively. Findings from the present study suggest that B. disticha could be a good prospective source of antioxidant and anticancer agents. Therefore, further research on the isolation and purification of compounds from these extracts are indispensable.     

Interferon Treatment of Ehrlich Ascites Tumor Cells: Effects on Exogenous mRNA Translation and tRNA Inactivation in the Cell Extract

We reported earlier that in cell extracts that were prepared from interferon-treated Ehrlich ascites tumor cells and preincubated and passed through Sephadex G-25 (S30_INT), the translation of exogenous mRNA (viral and host) was impaired and the impairment could be overcome to a large extent by adding a crude tRNA preparation from Ehrlich ascites tumor cells but not from Escherichia coli. We find now that the rate of inactivation of some tRNA's (especially those specific for leucine, lysine, and serine) but not those of many others is faster in S30_INT than in corresponding extracts from control cells. This increased rate of tRNA inactivation may perhaps account for the need for added RNA to overcome at least partially the impairment of translation in S30_INT. The relationship of the increased rate of tRNA inactivation to the antiviral effect of interferon is unclear. So far no significant difference has been detected in the amount of tRNA needed to overcome the impairment of encephalomyocarditis virus RNA translation in S30_INT between tRNA from interferon-treated cells and tRNA from control cells. Furthermore, no difference was found in the rate of inactivation in S30_INT between leucine-specific tRNA's from interferon-treated and from control cells. tRNA's specific for leucine and lysine were not inactivated (unless very slowly) during incubation under our conditions in an extract from interferon-treated (or from control) cells unless the extract had been passed through Sephadex G-25 or dialyzed. The translation of exogenous mRNA was, however, impaired in an extract from interferon-treated cells that had not been passed through Sephadex G-25. This impairment was apparently not overcome by added tRNA.     

Effects of bleaching on the pharmacological and toxicological activities elicited by the aqueous extracts prepared from two “fire corals” collected in the Mexican Caribbean

Hydrocorals of the genus Millepora are abundant skeleton-forming inhabitants of coral reefs around the world. These species are popularly known as “fire corals” since contact with them causes severe pain, skin eruptions and blisters as a result of the release of unidentified toxins. Millepora species associate with photosynthetic dinoflagellates of the genus Symbiodinium (“zooxanthellae”), and up to now the role of these symbionts in the toxic effects induced by the “fire corals” is unknown. In this study, we compared the hemolytic, vasoconstrictor, and phospholipase A₂ (PLA₂) activities of the crude aqueous extracts prepared from normal and bleached specimens of two hydrocorals collected in the Mexican Caribbean, Milleporaalcicornis and Millepora complanata. Electrophoretic analysis revealed some differences between the protein profiles of the extracts prepared from normal and bleached specimens. Bleaching decreased, but not abolished, the hemolytic effect induced by the hydrocorals extracts and the phospholipase A₂ activity of M. complanata extract. Furthermore, it did not modify the enzymatic activity of M. alcicornis extract and vasoconstriction elicited by both extracts. Our results suggest that the presence of the symbionts does not importantly influence the pharmacological and toxic effects induced by Millepora ssp. extracts, and indicate that cnidarians are the main source of the bioactive compounds.     

Preliminary screening for antibacterial and antimycobacterial activity of actinomycetes from less explored ecosystems

Actinomycetes from less explored ecosystems were screened for antibacterial and antimycobacterial activity. Crude bioactive compounds were produced by growing these strains by shake flask fermentation using soybean meal medium. Culture supernatant and mycelia were extracted with ethyl acetate and methanol, respectively. Antibacterial activity of crude extracts was tested by disc diffusion method against gram positive and gram negative bacteria. Actinomycete strains D10, D5, NEK5, ANS2, M104 and R2 showed prominent activity. Culture filtrates and crude extracts were tested against standard strain Mycobacterium tuberculosis H₃₇Rv and drug sensitive and drug resistant clinical isolates of M. tuberculosis by luciferase reporter phage (LRP) assay. Considerable variation was observed in antimycobacterial activity between actinomycete culture filtrates and solvent extracts. Actinomycete strains viz., D10, D5 (desert), CSA14 (forest), CA33 (alkaline soil), NEK5 (Neem plant), MSU, ANS2, R2 and M104 (marine) screened in the present study were found to be highly potent showing good antibacterial and antimycobacterial activity. Five of them such as A3, CSA1, EE9, ANS5 and R9 were exclusively active against M. tuberculosis. Secretary products of actinomycetes of rare ecosystems are meant to antagonize organisms in their respective environments. These are likely to be novel antimycobacterial compounds as they unknown to human pathogens.     

Investigating the antiangiogenic potential of Rumex vesicarius (humeidh), anticancer activity in cancer cell lines and assessment of developmental toxicity in zebrafish embryos

Recent trends in anticancer therapy is to use therapeutic agents which not only kill the cancer cell, but are less toxic to surrounding normal cells/tissue. One approach is to cut the nutrient supply to growing tumor cells, by blocking the formation of new blood vessels around the tumor. As the phytochemicals and botanical crude extracts have proven their efficacy as natural antiangiogenic agents with minimum toxicities, there is need to explore varieties of medicinal plants for novel antiangiogenic compounds.Rumex vesicarius L. (Humeidh), is an annual herbal plant with proven medicinal values. The antiangiogenic potential, and developmental toxicity of humeidh in experimental animal models has never been studied before. The crude extracts were prepared from the roots, stems, leaves and flowers of Rumex vesicarius L. in methanol, chloroform, ethyl acetate and n-hexane. The developmental toxicity screening in zebrafish embryos, has revealed that Rumex vesicarius was not toxic to zebrafish embryos. The chloroform stem extract showed significant level of antiangiogenic activity in zebrafish angiogenic assay on a dose dependent manner. Thirty five (35) bioactive compounds were identified by gas chromatography mass spectrophotometry (GC–MS) analysis in the stem extract of Rumex vesicarius. Propanoic acid, 2-[(trimethylsilyl)oxy]-, trimethylsilyl ester, Butane, 1,2,3-tris(trimethylsiloxy), and Butanedioic acid, bis(trimethylsilyl) ester were identified as major compound present in the stem of R. vasicarius.The anticancer activity of roots, stem, leaves and flowers crude extract was evaluated in human breast cancer (MCF7), human colon carcinoma (Lovo, and Caco-2), human hepatocellular carcinoma (HepG2) cell lines. Most of the crude extracts did not show significant level of cytotoxicity in tested cancer cells line, except, chloroform extract of stem which exhibited strong anticancer activity in all tested cancer cells with IC₅₀ values in micro molar range.Based on these results, it is recommended that formulation prepared from R. vesicarius can further be tested in clinical trials in order to explore its therapeutic potential as an effective and safe natural anticancer product.     

Comparative study of three herbal formulations against dengue vectors Aedes aegypti

The efficacy of three formulations (i.e., natural lavender crude, essential oil, and gel) extracted from Lavender angustifolia was tested against vectors of the epidemic dengue virus, Aedesaegypti, to evaluate their larvicidal activity effect. The ethanolic extract of the lavender crude was prepared using a rotary evaporator, while the other extracts, such as essential oil and gel, were obtained from iHerb, a supplier of medicinal herbs in the US. The mortality rate of larvae was evaluated 24 h after exposure. Larvicidal activity of the lavender crude was 91% mortality at 150 ppm, 94% for essential oil at a concentration of 3000 ppm, and 97% for lavender gel at a 1000 ppm. Natural lavender crude was one of the most promising extracts tested against Ae.aegypti larvae, with lethal concentrations at LC₅₀ and LC₉₀ of 76.4 and 174.5 ppm post-treatment. The essential oil had the least effect on mosquito larvae, with LC₅₀ and LC₉₀ reaching 1814.8 and 3381.9 ppm, respectively. The lavender gel was moderately effective against Ae. aegypti larvae, with LC₅₀ and LC₉₀ values reaching 416.3 and 987.7 ppm after exposure. The occurrence of morphological abnormalities in the larvae treated with the three compounds, in turn, resulted in an incomplete life cycle. Therefore, our results indicated that natural lavender crude displayed the highest larvicidal activity against larvae, followed by gel and essential oil. Thus, this study concluded that lavender crude is an effective, eco-friendly compound that can be used as an alternative to chemical products to control vector-borne epidemic diseases.     

Stable Isotope Fractionation of Tetrachloroethene during Reductive Dechlorination by Sulfurospirillum multivorans and Desulfitobacterium sp. Strain PCE-S and Abiotic Reactions with Cyanocobalamin

Carbon stable isotope fractionation of tetrachloroethene (PCE) during reductive dechlorination by whole cells and crude extracts of Sulfurospirillum multivorans and Desulfitobacterium sp. strain PCE-S and the abiotic reaction with cyanocobalamin (vitamin B₁₂) was studied. Fractionation was largest during the reaction with cyanocobalamin with αC = 1.0132. Stable isotope fractionation was lower but still in a similar order of magnitude for Desulfitobacterium sp. PCE-S (αC = 1.0052 to 1.0098). The isotope fractionation of PCE during dehalogenation by S. multivorans was lower by 1 order of magnitude (αC = 1.00042 to 1.0017). Additionally, an increase in isotope fractionation was observed with a decrease in cell integrity for both strains. For Desulfitobacterium sp. strain PCE-S, the carbon stable isotope fractionation factors were 1.0052 and 1.0089 for growing cells and crude extracts, respectively. For S. multivorans, αC values were 1.00042, 1.00097, and 1.0017 for growing cells, crude extracts, and the purified PCE reductive dehalogenase, respectively. For the field application of stable isotope fractionation, care is needed as fractionation may vary by more than an order of magnitude depending on the bacteria present, responsible for degradation.     

Isolation and characterization of antiprotozoal compound-producing Streptomyces species from Mongolian soils

Natural resources are recognized as important sources of potential drugs for treating various infections, and microorganisms are a rich natural source of diverse compounds. Among the world's microorganisms, actinomycetes, which are abundant in soil and marine, are the well-known producers of a wide range of bioactive secondary metabolites and antibiotics. In the present study, four actinomycetes (samples N25, N6, N18, and N12) were isolated from soil samples in Mongolia. Phylogenetic analysis of these isolates revealed that they share the highest similarity with Streptomyces canus (N25), S. cirratus (N6), S. bacillaris (N18) and S. peucetius (N12), based on 16S rRNA gene sequencing. Crude extracts were obtained from them using ethyl acetate, and the crude fractions were separated by thin layer chromatography. The fractions were then evaluated for their cytotoxicities and their anti-Toxoplasma and antimalarial activities in vitro. The S. canus (N25) crude extract was selected for further chemical characterization based on its antiprotozoal activities. Using liquid chromatography-high resolution mass spectrometry, phenazine-1-carboxylic acid (PCA) was detected and identified in the active fractions of the metabolites from strain N25. We next confirmed that commercially available PCA possesses antiprotozoal activity against T. gondii (IC₅₀: 55.5 μg/ml) and Plasmodium falciparum (IC₅₀: 6.4 μg/ml) in vitro. The results of this study reveal that soil actinomycetes are potential sources of antiprotozoal compounds, and that PCA merits further investigation as an anti-protozoal agent.     

Comparative chemical analysis and antifungal activity of Ochtodes secundiramea (Rhodophyta) extracts obtained using different biomass processing methods

The activities of bioactive compounds can be influenced by countless factors, including post-collection sample treatment. In this study, the activities of Ochtodes secundiramea extracts obtained using different processes are compared; the biomass was macerated immediately, lyophilized in liquid nitrogen, or dried in an oven at 50 °C after collection. The chemical profiles of the extracts were evaluated using gas chromatography-mass spectrometry (GC-MS), and their biological activities were assessed using qualitative and quantitative bioautography thin-layer chromatography (TLC) assays against phytopathogenic fungi. Preparative high-performance liquid chromatography (HPLC) was employed to isolate the major compound observed in semi-quantitative (CG-MS). The biomass processing methods were shown to influence the chemical profiles of the extracts that promote the oxidation of halogenated monoterpenes; however, C₁₀H₁₅Br₂Cl was the major compound identified in all of the extracts regardless of the preparation method used. Similarly, changes in qualitative antifungal activity were observed depending on the preparation method, even though the minimum amount of material required for the inhibition of fungal growth (the activity detection limit) was 5 μg in all cases. The activity detection limits for the HPLC-purified majority compound were 5 and 10 μg against Cladosporium sphaerospermum and Colletotrichum lagenarium, respectively; these values are similar to those obtained for the crude extracts. These results point towards the possibility of using these crude extracts for the control of anthracnose in cucumbers post-harvest.     

In vitro cytotoxicity and genotoxicity of five Ochna species (Ochnaceae) with excellent antibacterial activity

Extracts and fractions of some Ochna species had excellent antibacterial activity. Before considering the potential therapeutic use of these extracts it is important to determine the safety of extracts. The cytotoxicity of Ochna natalitia, Ochna pretoriensis, Ochna pulchra, Ochna gamostigmata, and Ochna serrulata (Ochnaceae) was determined in monkey kidney (Vero) cells, human hepatocellular carcinoma (C3A) cells and bovine dermis cells using the mitochondrial viability MTT assay. Their potential mutagenic effects were also determined using the Ames test with strains Salmonella typhimurium TA98 and TA100 with and without metabolic activation. The LC₅₀ values (the lethal concentration at which 50% of the cells are killed) of the extracts on the various cell lines ranged from 26 to 99 μg/ml. None of the plant species was mutagenic (mutagenic index values ≤ 1.59 for TA98 and ≤ 0.92 for TA100). In a previous study, we determined the antibacterial activity of the five extracts against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Pseudomonas aeruginosa. From this we calculated the selectivity index (SI) values by dividing the LC₅₀ value by the minimum inhibitory concentration (MIC) to obtain the ratio of toxicity to bioactivity of each extract. The plant extracts had low SI values ≤ 1.307. This is a clear indication of non-selective toxicity, i.e. extracts are almost equally toxic to the bacteria and mammalian cell lines used in the assays. As a result, the extracts may have limited application as ingestible or intravenous therapeutic agents based on the in vitro findings. However, it may be necessary to also evaluate in vivo toxicity of the extracts in animal models as in vitro toxicity does not always equate to in vivo toxicity because of the difference in physiological microenvironment in live animals and tissue culture. Additionally, if it is the case that the toxic compounds are not the same as the active compounds, it may be possible to potentiate the extracts by the removal of toxic compounds and concentration of active compounds. The extracts may then be useful for development into treatments for topical bacterial infections.     

Natural products of Alternaria sp., an endophytic fungus isolated from Salvadora persica from Saudi Arabia

This study is to evaluate the potential of endophytic fungi of Salvadora persica for the production of bioactive compounds against pathogenic bacteria and fungi. Forty-two fungal isolates were obtained from 135 young and old stem and 125 root segments. Those 42 isolates representing ten fungi include: Trichoderma sp. (the most common), two species of Alternaria, Rhizopus arrhizus and 6 sterile mycelia. The ten fungi were grown in liquid culture and their crude extracts were tested against pathogenic bacteria and fungi. Nine crude extracts gave positive reactions against pathogenic bacteria of which Alternaria sp. (A8) was chosen further study. The fungal isolate was growing as sterile mycelium and was identified by phylogenetic analyses based on LSU rDNA sequence data and it might represent undescribed species of Alternaria. Sixty-two bioactive chemical compounds were identified from the ethyl acetate crude extracts of Alternaria sp., of which the following were recorded as major compounds in the active sub-fractions. These compounds showed strong antibacterial activity in combination.     

Quantification of biochemical compounds in Bauhinia Variegata Linn flower extract and its hepatoprotective effect

Liver disorders may occur as a result of exposure to chemical compounds capable of inducing the oxidative stress and hepatic injuries. The aim of present study was to investigate the effects of flower extracts of B. Variegata for the treatment of liver injury induced by the CCl₄. About 1 ml/kg body weight (b.w) of CCl4 was induced to experimental mice by intraperitoneal way for 14 days. The methanol and chloroform extracts (100, 200 and 300 mg/kg b.w) were administered to experimental animals for 14 days along with standard drug Silymarine (100 mg/kg b.w). The extracts alone showed no evidence of hepatic toxicity but animals exposed to CCl₄ without the treatment with B. Variegata presented variations in levels of liver enzymes, antioxidant enzymes, proteins and blood cells as well as injuries in liver cells were also observed during histopathological study. However, after the treatments especially with 300 mg/kg b.w of methanol flower extracts levels of liver markers (ALT, AST and ALP), antioxidant enzymes and blood cells decreases and turned towards normal levels. Whereas level of total proteins and bilirubin was improved and damaged liver cells were repaired. The curative activity of flower extracts can be correlated to the higher potential of antioxidants and occurrence of Quercetin and some other organic compounds those were investigated from flower extracts of B. Variegata during HPLC and GC-MS analysis. The finding of this study supports the use of B. Variegata flower formulation in folk medicines.     

Assessment of biological activity and UPLC–MS based chromatographic profiling of ethanolic extract of Ochradenus arabicus

Natural products from wild and medicinal plants, either in the form of crude extracts or pure compounds provide unlimited opportunities for new drug leads owing to the unmatched availability of chemical diversity. In the present study, the cytotoxic potential of crude ethanolic extract of Ochradenus arabicus was analyzed by MTT cell viability assay in MCF-7 adenocarcinoma breast cancer cells. We further investigated its effect against oxidative stress induced by anticancer drug doxorubicin. In addition, Ultra Performance Liquid Chromatography–Mass Spectrometry (UPLC–MS) based chromatographic profiling of crude extract of O. arabicus was performed. The MTT assay data showed that the extract is moderately toxic to the MCF-7 cells. However, its treatment alone does not induce oxidative stress while doxorubicin increases the level of oxidative stress in MCF-7 cells. Whereas, simultaneous treatment of plant extract and doxorubicin significantly (p < 0.05) decreased the level of intracellular reactive oxygen species (ROS) and lipid peroxidation while an increase in the reduced glutathione and superoxide dismutase activity was observed in time and dose dependent manner. Hence, our finding confirmed cytotoxic and antioxidant potential of crude extract of O. arabicus in MCF-7 cells. However, further investigations on O. arabicus as a potential chemotherapeutic agent are needed. The analysis of bioactive compounds present in the plant extracts involving the applications of common phytochemical screening assays such as chromatographic techniques is discussed.     

Evaluation of chemical constituents from Glehnia littoralis for antiproliferative activity against HT-29 human colon cancer cells

In order to investigate the potential of Glehnia littoralis as a cancer chemopreventive food, antiproliferative effects of both its crude extracts and solvent-partitioned fractions (n-hexane, 85% aq. MeOH, n-BuOH, and water) were evaluated in HT-29 human colon cancer cells. Its crude extracts and solvent-partitioned fractions exhibited dose-dependent inhibitory effects on the cell proliferation. Especially, n-hexane and 85% aq. MeOH fractions exhibited a high antiproliferative effect, induced apoptosis as determined by 4,6-diamidino-2-phenylindole (DAPI) staining, and reduced mRNA expression of Bcl-2, cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS). Systematic separation of n-hexane and 85% aq. MeOH fractions by diverse chromatographic methods led to the isolation of furanocoumarins (1–4) and polyacetylene alcohols (5–7). All compounds exhibited dose-dependent inhibitory effects on the cell proliferation. These results indicated that potent inhibitory activity of G. littoralis on proliferation of cancer cells can be significantly traceable to furanocoumarines and polyacetylenic alcohols contained in G. littoralis.     

Crude Extracts and Secondary Metabolites of Epichloë bromicola against Phytophthora infestans

Potato late blight caused by Phytophthora infestans is still one of the main factors limiting potato production. Epichloë spp. can provide host plants with various resistances, which makes them show great potential in the biological control of diseases. In this study, we explored the potential biological activity of crude extracts of 20 strains of Epichloë bromicola to control P. infestans. The crude extracts of strains 1 and 8 showed significant antifungal activity with an inhibition rate of 88 % and 81 %, respectively, and showed different effects on the mycelium morphology of P. infestans observed by scanning electron microscopy. Moreover, the two crude extracts demonstrated an interesting therapeutic and protective effect on potato late blight, and none of the extracts had an adverse effect against zebrafish embryos. A total of 13 metabolites were isolated from the crude extract of strain 8, and these tested compounds showed a weak antifungal effect and the inhibition rate was less than 80 %. These findings suggested that strains 1 and 8 have potential for biocontrol of late potato blight.     

Acridone alkaloids from Vepris verdoorniana (Excell & Mendonça) Mziray (Rutaceae)

Two new acridone alkaloids, verdoocridone A (1) and B (4), together with fifteen known compounds were isolated from methanol extracts of the roots and leaves of Vepris verdoorniana. The structures of all compounds were determined by comprehensive spectroscopic analyses (1D and 2D NMR, EI- and ESI–MS). The ¹³C NMR values of 1,2,3,5-tetramethoxy-N-methylacridone (2) and 5-methoxyaborinine (3) are also reported. The crude extracts and compounds (1-6) were tested for their antimicrobial activity. The test delivered moderate activities for crude extracts and compounds 1, 5 and 6 against the bacterium Staphylococcus aureus and the fungi Mucor meihei and Candida albicans with MIC values between 115 and 180 μg/mL for extracts and between 21.3 and 29.4 μM for compounds, compared to gentamycin with 0.2 μM and nystatin with 5.2 μM against both fungi. The determination of the radical scanvenging activity using 1,1-dephenyl-2-picrylhydrazyl (DPPH) assay gave moderate antioxidant values for all tested compounds, with IC₅₀ between 0.29 and 0.41 μM, compared to the standard 3-t-butyl-4-hydroxyanisole (BHA) displaying 0.03 μM.     

Isolation of substances with antiproliferative and apoptosis-inducing activities against leukemia cells from the leaves of Zanthoxylum ailanthoides Sieb. & Zucc

Extraction of the leaves of Zanthoxylum ailanthoides Sieb. & Zucc. affords extracts and four isolated compounds which exhibit activities against leukemia cells. The chloroform-soluble fraction (ZAC) of the crude extract of this plant showed cytotoxic activity against human promyelocytic leukemia (HL-60) and myelomonocytic leukemia (WEHI-3) cells with IC₅₀ values of 73.06 and 42.22 μg/mL, respectively. The active ZAC was further separated to yield pheophorbide-a methyl ester (1), pheophorbide-b methyl ester (2), 13²-hydroxyl (13²-S) pheophorbide-a methyl ester (3) and 13²-hydroxyl (13²-R) pheophorbide-b methyl ester (4) whose structures were confirmed by spectroscopic methods. Compounds 2-4 showed cytotoxic activities against both leukemia cells with IC₅₀ value in the range of 46.76-79.43 nM, whereas compound 1 exhibited only weak cytotoxic activity. The extracts and compounds 1-4 also induced apoptosis and DNA damage in leukemia cells after treatment. The results suggested that the Z. ailanthoides is biologically active against leukemia cells.     

Isolation of antibacterial compounds from Quercus dilatata L. through bioassay guided fractionation

Background

Four medicinal plants (Chrozophora hierosolymitana Spreng, Chrysanthemum leucanthemum L., Ephedra gerardiana Wall. ex Stapf, and Quercus dilatata L.) used by indigenous healers to treat various infectious diseases were selected for the present study. The major objective of the present study was isolation and characterization of antimicrobial components from the crude plant extracts using bioassay guided fractionation.

Methods

Seven methanolic extracts of the four plants were screened to identify any antimicrobial agents present in them. The active crude plant extract was fractionated first by solvent partitioning and then by HPLC. Characterization of the active fractions was done by using spectrophotometer.

Results

All the seven methanolic extracts showed low antifungal activity, however, when these extracts were tested for antibacterial activity, significant activity was exhibited by two extracts. The extract of aerial parts of Q. dilatata was most active and therefore, was selected for further analysis. Initially fractionation was done by solvent-solvent partitioning and out of six partitioned fractions, ethanol fraction was selected on the basis of results of antibacterial activity and phytochemical analysis. Further, fractionation was carried out by RP- HPLC and purified active subfractions were characterized by comparing their absorption spectra with that of the known natural products isolated from the plants of Quercus genus.

Discussion and conclusion

The results suggest that this is the first report of the isolated antibacterial compounds from this genus.