Bushra Mirza

Survey of artemisinin production by diverse Artemisia species in northern Pakistan

BackgroundArtemisinin is the current drug of choice for treatment of malaria and a number of other diseases. It is obtained from the annual herb, Artemisia annua and some microbial sources by genetic engineering. There is a great concern that the artemisinin production at current rate will not meet the increasing demand by the pharmaceutical industry, so looking for additional sources is imperative.MethodsIn current study, artemisinin concentration was analysed and compared in the flowers, leaves, roots and stems of Artemisia annua and 14 other Artemisia species including two varieties each for Artemisia roxburghiana and Artemisia dracunculus using high performance liquid chromatography (HPLC).ResultsThe highest artemisinin concentration was detected in the leaves (0.44 ± 0.03%) and flowers (0.42 ± 0.03%) of A. annua, followed by the flowers (0.34 ± .02%) of A. bushriences and leaves (0.27 ± 0%) of A. dracunculus var dracunculus. The average concentration of artemisinin varied in the order of flowers > leaves > stems > roots.ConclusionThis study identifies twelve novel plant sources of artemisinin, which may be helpful for pharmaceutical production of artemisinin. This is the first report of quantitative comparison of artemisinin among a large number of Artemisia species.

Synthesis, Chemical Characterization and Biological Screening for Cytotoxicity and Antitumor Activity of Organotin (IV) Derivatives of 3,4-Methylenedioxy 6-nitrophenylpropenoic Acid

A series of mono-, di- and triorganotin compounds with general formulae [RSnL(2)Cl], R = Bu (compound 3), [R(2)SnL(2)], where R = Me, Et, Bu, Oct (compounds 1, 2, 4 and 6) and [R(3)SnL], where R = Bu, Cy and Ph (compounds 5, 7 and 8) and where L = 3,4-methylenedioxy-6-nitrophenylpropenoic acid have been prepared and characterized by elemental analysis, multinuclear ((1)H-, (13)C- and (119)Sn-) NMR and mass spectrometry. The ligand and its respective organotin complexes were screened for cytotoxicity using the brine shrimp lethality assay and for antitumor activity using the crown gall tumor inhibition (potato disc) assay. The bioassay results support the conclusion that the biological activities of these synthetic compounds are in the following order: [RSnL(2)Cl] < [R(2)SnL(2)] < [R(3)SnL].

High-quality plant DNA extraction for PCR: an easy approach.

Polymerase chain reaction has found wide applications in modern research involving transformations and other genomic studies. For reproducible PCR results, however, the quantity and quality of template DNA is of considerable importance. A simple and efficient plant DNA extraction procedure for isolation of high-quality DNA from plant tissues is presented here. It requires maceration of plant tissue of about 1.0 cm2 (e.g. of a leaf blade) in DNA extraction buffer (100 mM Tris-HCl, 100 mM EDTA, 250 mM NaCl) using 1.5-mL microfuge tubes, followed by cell lysis with 20% SDS, and DNA extraction with phenol: chloroform: iso-amyl alcohol (25:24:1). Hydrated ether is then used to remove polysaccharides and other contaminants from the DNA preparation. Average DNA yield is 20–30 μg cm−2 for fresh tissues, and ratio of absorbance at 260 nm to absorbance at 280 nm is 1.5–1.8. The DNA is quite suitable for PCR using microsatellites, RAPD and specific markers for recombinant selection. Amplifications have been obtained for these markers by using template DNA extracted from fresh as well as frozen leaf tissues of various plants, including barley, oat, potato and tomato. DNA stored for more than 2 years has been successfully amplified with microsatellite markers, which shows suitability of this method after long-term storage of DNA. Besides, the ease of use and cost-effectiveness make the procedure attractive.

In Planta Transformation of Tomato

In this study, in planta transformation of tomato (Solanum lycopersicum L.), using fruit injection and floral dip, is reported. Agrobacterium tumefaciens strain EHA 105 containing one of three constructs, i.e., pROKIIAP1GUSint (carrying the Apetala 1 [AP1] gene), pROKIILFYGUSint (carrying the LEAFY [LFY] gene), or p35SGUSint (carrying the β-glucuronidase [GUS] gene), was used for plant transformation. For fruit injection transformation, no significant effects (p > 0.05) of the construct used were observed. The highest frequency of transformation was obtained following 48-h incubation of tomato fruit with bacterial cells harboring either one of the three constructs; transformation frequencies of 17%, 19%, and 21% for AP1, LFY, and GUS gene constructs, respectively, were obtained. When fruit maturity was evaluated in fruit injection experiments, mature red fruit resulted in higher frequency of transformants than immature green fruit with 40%, 35%, and 42% for AP1, LFY, and GUS gene constructs, respectively. For floral dip transformation, a higher number of transformants was obtained when the GUS gene construct was used instead of either the AP1 or LFY gene construct, thus suggesting a possible inhibitory effect of the flowering genes used. When flowers were transformed prior to rather than following pollination, they yielded a higher transformation frequency, 12% for the LFY construct and 23% for the GUS construct (p < 0.05), although no transformant was obtained with the AP1 gene construct. All putative GUS-positive transformants were analyzed using polymerase chain reaction and confirmed for the presence of the transgene. Compared to control plants, transgenic plants carrying either the AP1 or LFY transgene flowered earlier and showed several different morphological characters.

Di‐ and Triorganotin(IV) Esters of 3,4‐Methylenedioxyphenylpropenoic Acid: Synthesis, Spectroscopic Characterization and Biological Screening for Antimicrobial, Cytotoxic and Antitumor Activities

Nine biologically significant organotin(IV) esters of 3,4‐Methylenedioxyphenylpropenoic acid (L) were synthesized with the general formulae [R2SnL2], where R includes Me(1), Et(3), But(4), Oct(5), Ph(8), and [R3SnL], in which R is Me(2), Cy(6), Ph(7), and But(9). The acid and its compounds were characterized by basic analytical techniques comprising elemental analysis, FTIR and mass spectrometry in solid state and by Multinuclear (1H, 13C and 119Sn) NMR in solution form, which provides some important information about the different coordination behaviors of metal in both solid and solution. Methylenedioxy moiety in these compounds enhances the biological activity of these compounds. These compounds were screened for a range of biological activities. Antibacterial activities were determined against six pathogenic bacterial strains, three gram‐positive and three gram‐negative, the activities were measured in terms of inhibition zones (mm). Results demonstrate that diorganotin derivatives are more active than triorganotin derivatives and ligand acid. Antifungal activity was determined against six pathogenic fungal strains, cytotoxicity by the brine shrimp lethality assay, and antitumor activity by crown gall tumor inhibition (potato disc) assay. Results for antifungal activity, cytotoxicity, and antitumor activity of these compounds demonstrate that triorganotin derivatives are more active than diorganotin derivatives and ligand. Finally, the results were compared with similar reports in the literature.

Biologically Active Withanolides from Withania coagulans

Bioassay-directed isolation and purification of the crude extract of Withania coagulans, using two assays for cancer chemopreventive mechanisms, led to the isolation of three new steroidal lactones, withacoagulin G (1), withacoagulin H (2), and withacoagulin I (3), along with six known derivatives (4-9). The structures and absolute stereochemistry of these compounds were determined on the basis of spectroscopic analyses, including 1D and 2D NMR, mass spectrometry, and CD analyses. The structure of 1 was confirmed using X-ray diffraction methods. Compounds 1-9 inhibited nitric oxide production in lipopolysaccharide-activated murine macrophage RAW 264.7 cells with IC(50) values in the range of 1.9-38.2 μM. Compounds 1 and 2 were the most active (IC(50) 3.1 and 1.9 μM, respectively). Withanolides 1-9 exhibited inhibition of tumor necrosis factor-α (TNF-α)-induced nuclear factor-kappa B (NF-κB) activation with IC(50) values in the range of 1.60-12.4 μM.

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

BackgroundFour 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.MethodsSeven 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.ResultsAll 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 conclusionThe results suggest that this is the first report of the isolated antibacterial compounds from this genus.

Extraction optimization of medicinally important metabolites from Datura innoxia Mill.: an in vitro biological and phytochemical investigation

BackgroundThe present study aims to probe the impact of polarity dependent extraction efficiency variation on pharmacological spectrum of Datura innoxia Mill. in order to reconnoiter its underexplored therapeutic potential.MethodsA range of solvent extracts was subjected to phytochemical and biological assays to find the most proficient solvent system and plant part for each type of bioactivity. Total phenolic and flavonoid contents were determined colorimetrically and specific polyphenols were quantified by HPLC-DAD analysis. The samples were biologically evaluated by employing multimode antioxidant, cytotoxic, protein kinase inhibition and antimicrobial assays.ResultsAmong all the solvents used, maximum percent extract recovery (33.28 %) was obtained in aqueous leaf extract. The highest amount of gallic acid equivalent phenolic and quercetin equivalent flavonoid content was obtained in the distilled water and ethyl acetate-ethanol extracts of leaf i.e., 29.91 ± 0.12 and 15.68 ± 0.18 mg/g dry weight (DW) respectively. Reverse phase HPLC-DAD based quantification revealed the presence of significant amounts of catechin, caffiec acid, apigenin and rutin ranging from 0.16 to 5.41 mg/g DW. Highest DPPH radical scavenging activity (IC50 = 16.14 μg/ml) was displayed by the ethyl acetate-acetone stem extract. Maximum total antioxidant capacity and reducing power potential were recorded in the aqueous leaf and ethyl acetate stem extracts i.e., 46.98 ± 0.24 and 15.35 ± 0.61 mg ascorbic acid equivalent/g DW respectively. Cytotoxicity against brine shrimps categorized 25 % of the leaf, 16 % of the stem and 8.3 % of the fruit extracts as highly potent (LC50 ≤ 100 μg/ml). Significant cytotoxicity against human leukemia (THP-1) cell line was exhibited by the chloroform and n-hexane fruit extracts with IC50 4.52 and 3.49 μg/ml respectively. Ethyl acetate and methanol-chloroform extracts of leaf and stem exhibited conspicuous protein kinase inhibitory activity against Streptomyces 85E strain with 22 mm bald phenotype. A noteworthy antimicrobial activity was exhibited by leaf extracts against Micrococcus luteus and n-hexane fruit extract against Aspergillus niger (MIC 3.70 and 12.5 μg/ml respectively).ConclusionMultiple solvent system is a crucial variable to retrieve pharmacological potential of medicinal plants and D. innoxia can be envisaged as a novel source of natural antioxidants, antimicrobials and anticancer compounds.

Plants Fagonia cretica L. and Hedera nepalensis K. Koch contain natural compounds with potent dipeptidyl peptidase-4 (DPP-4) inhibitory activity

ETHNOPHARMACOLOGICAL RELEVANCE The two plants investigated here (Fagonia cretica L. and Hedera nepalensis K. Koch) have been previously reported as natural folk medicines for the treatment of diabetes but until now no scientific investigation of potential anti-diabetic effects has been reported. MATERIALS AND METHODS In vitro inhibitory effect of the two tested plants and their five isolated compounds on the dipeptidyl peptidase 4 (DPP-4) was studied for the assessment of anti-diabetic activity. RESULTS A crude extract of Fagonia cretica possessed good inhibitory activity (IC₅₀ value: 38.1 μg/ml) which was also present in its n-hexane (FCN), ethyl acetate (FCE) or aqueous (FCA) fractions. A crude extract of Hedera nepalensis (HNC) possessed even higher inhibitory activity (IC50 value: 17.2 μg/ml) and this activity was largely retained when further fractionated in either ethyl acetate (HNE; IC50: 34.4 μg/ml) or n-hexane (HNN; 34.2 μg/ml). Bioactivity guided isolation led to the identification of four known compounds (isolated for the first time) from Fagonia cretica: quinovic acid (1), quinovic acid-3β-O-β-D-glycopyranoside (2), quinovic acid-3β-O-β-D-glucopyranosyl-(28→1)-β-D-glucopyranosyl ester (3), and stigmasterol (4) all of which inhibited DPP-4 activity (IC₅₀: 30.7, 57.9, 23.5 and >100 µM, respectively). The fifth DPP-4 inhibitor, the triterpenoid lupeol (5) was identified in Hedera nepalensis (IC₅₀: 31.6 μM). CONCLUSION The experimental study revealed that Fagonia cretica and Hedera nepalensis contain compounds with significant DPP-4 inhibitory activity which should be further investigated for their anti-diabetic potential.

Agrobacterium-Mediated Transformation of Tomato with rolB Gene Results in Enhancement of Fruit Quality and Foliar Resistance against Fungal Pathogens

Tomato (Solanum lycopersicum L.) is the second most important cultivated crop next to potato, worldwide. Tomato serves as an important source of antioxidants in human diet. Alternaria solani and Fusarium oxysporum cause early blight and vascular wilt of tomato, respectively, resulting in severe crop losses. The foremost objective of the present study was to generate transgenic tomato plants with rolB gene and evaluate its effect on plant morphology, nutritional contents, yield and resistance against fungal infection. Tomato cv. Rio Grande was transformed via Agrobacterium tumefaciens harbouring rolB gene of Agrobacterium rhizogenes. rolB. Biochemical analyses showed considerable improvement in nutritional quality of transgenic tomato fruits as indicated by 62% increase in lycopene content, 225% in ascorbic acid content, 58% in total phenolics and 26% in free radical scavenging activity. Furthermore, rolB gene significantly improved the defence response of leaves of transgenic plants against two pathogenic fungal strains A. solani and F. oxysporum. Contrarily, transformed plants exhibited altered morphology and reduced fruit yield. In conclusion, rolB gene from A. rhizogenes can be used to generate transgenic tomato with increased nutritional contents of fruits as well as improved foliar tolerance against fungal pathogens.