M. Rowshanul Habib

Tagetes erecta Linn. and its mosquitocidal potency against Culex quinquefasciatus

OBJECTIVE To investigate mosquitocidal effects of ethanolic extract of flowers of Tagetes erecta (T. erecta) and its chloroform and petroleum ether soluble fractions against the larvae of Culex quinquefasciatus (Cx. quinquefasciatus). METHODS The fresh flowers of T. erecta were extracted in cold with ethanol (5.0 L) and after concentration, the ethanol extract was fractionated with chloroform and petroleum ether to afford a brownish syrupy suspension of ethanol extract (50.0 g), petroleum ether soluble fraction (18.6 g) and chloroform soluble fraction (23.8 g). The larvicidal effect of ethanol extract and their solvent fractions were determined by the standard procedure of WHO against different instars of Cx. quinquefasciatus. RESULTS Among the tested samples the chloroform soluble fractions showed the highest toxicity and consequently, the lowest LC50 values (14.14 µg/mL, 17.06 µg/mL, 36.88 µg/mL and 75.48 µg/mL) for all the instars larvae of Cx. quinquefasciatus. The larvae showed comparative tolerance in the course of increasing age and time. CONCLUSIONS It can be concluded that the flowers of T. erecta are very effective natural larvicide and could be useful against Cx. quinquefasciatus.

Antimicrobial and Cytotoxic Activity of Di-(2-ethylhexyl) Phthalate and Anhydrosophoradiol-3-acetate Isolated from Calotropis gigantea (Linn.) Flower

Abstract A phytoehemieal study on the flowe r of Calotropis gigantea (Linn.) using silica gel column chromatography and preparative thin layer chromatography, led to the first time isolation of Di-(2-ethylhexyl) phthalate (compound 1) and anhydrosophoradiol-3-aeetate (compound 2). The structures of these compounds were confirmed by spectroscopic analyses (IR, HRTOFMS and NMR). The antibacterial and antifungal activities of ethyl acetate extract, compound 1 and compound 2 were measured using the disc diffusion method. Ethyl acetate extract and compound 1 presented better results than compound 2. The minimum inhibitory concentrations (MICs) of the extract and compounds were found to be in the range of 16-128 μg/ml. The cytotoxicity (LC50) against brine shrimp nauplii (Artemia saiina) were also evaluated and found to be 14.61μg/ml for ethyl acetate, 9.19 μg/ml for compound 1 and 15.55 μg/ml for compound 2.

Antimicrobial Activity of Some Schiff Bases Derived from Benzoin, Salicylaldehyde, Aminophenol and 2,4 Dinitrophenyl Hydrazine

The antibacterial and antifungal activities of three schiff bases were evaluated against some pathogenic bacteria and fungi. Parallel experiments were also carried out with standard drugs (Kanamycin for bacteria and Nystatin for fungi). Two compounds [N-(1-phenyl-2-hydroxy-2phenylethylidine)-2‘,4’ dinitrophenyl hydrazine, abbreviated as PDH and N-(2-hydroxy benzylidine)-2’-hydroxy imine, abbreviated as HHP] showed significant antimicrobial activities. The rest one [N-(1-phenyl 2-hydroxy-2 phenyl ethylidine) 2’-hydroxy phenyl imine, abbreviated as PHP] showed moderate activity. All these three compounds were found to possess pronounced cytotoxic effect. These compounds can be considered as potent antimicrobial agents.

Antishigellosis and Cytotoxic Potency of Crude Extracts and Isolated Constituents from Duranta repens

The crude ethanol extracts (stem and fruits), their fractions and two triterpenes, β-Amyrin and 12-Oleanene 3β, 21β-diol, isolated as a mixture from the chloroform soluble fraction of an ethanolic extract of Duranta repens stem, were evaluated for antibacterial, antifungal activities by the disc diffusion method and cytotoxicity by brine shrimp lethality bioassay. The structures of the two compounds were confirmed by IR, 1 H-NMR, 13 C-NMR and LC-MS spectral data. The chloroform soluble fraction of stem and ethanol extract of fruits possess potent antishigellosis activity and also exhibited moderate activity against some pathogenic bacteria and fungi but the isolated compound 1 (mixture of β-Amyrin and 12-Oleanene 3β, 21β-diol) showed mild to moderate inhibitory activity to microbial growth. The minimum inhibitory concentrations (MICs) of the extracts (stem and fruits), their fractions and compound 1 were found to be in the range of 32~128 μg/ml. The chloroform soluble fractions of stem and ethanol extract of fruit showed significant cytotoxicity with LC50 value of 0.94 μg/ml and 0.49 μg/ml, respectively against brine shrimp larvae.

Cytotoxic chemicals from Calotropis gigantea flower

Calotropis gigantea L. (Asclepiadaceae), popularly known as “Boro Akanda”, is a moderate to large-sized perennial shrub widely grown throughout the Indian subcontinent, including Bangladesh [1]. The chemical constituents of Calotropis gigantea have been extensively investigated, leading to the isolation of many cytotoxic cardenolide glycosides [2–7], pregnanone [8], a nonprotein amino acid [9], terpenes [10–12], flavonoids [13], and steroids [7, 14]. In this work, we report the cytotoxic potency of di-(2-ethylhexyl)phthalate (1) and anhydrosophoradiol-3-acetate (2) from Calotropis gigantea flower against human vulval-derived epidermoid carcinoma cells (A431 cell line). The flowers of Calotropis gigantea were collected from Rajshahi University campus, Rajshahi, Bangladesh and the identification of this plant was confirmed by Prof. A. T. M. Naderuzzaman, Department of Botany, Rajshahi University. A voucher specimen (No. 1A. Alam, Collection date 15.08.2004) was deposited in the Department of Botany, University of Rajshahi. The shed-dried powdered flower (1.0 kg) of Calotropis gigantea was extracted with ethyl acetate (2.0 L) at room temperature. The solvent was completely removed by a rotary vacuum evaporator from the crude extract to yield a residue of 38 g. Then crude ethyl acetate extract (15 g) was subject to silica gel (60–120 mesh) chromatography using n-hexane with a gradient of ethyl acetate up to 100% and followed by chloroform to afford compounds 1 and 2. Di-(2-ethylhexyl)phthalate (1). Colorless oily liquid. 1H NMR (400 MHz, CDCl3, , ppm, J/Hz): 0.84 (3H, t, J = 5.3, H-1), 1.23–1.40 (2H, m, H-2), 1.23–1.40 (2H, m, H-3), 1.23–1.40 (2H, m, H-4), 2.606 (1H, m, H-5), 4.15 (2H, m, H-6), 2.30 (2H, dq, J = 4.3, H-8), 0.93 (3H, t, J = 4.3, H-9), 6.96 (1H, dd, J = 6.3–2.2, H-11), 7.11 (1H, dd, J = 6.3–2.2, H-12). 13C NMR (150 MHz, CDCl3, , ppm): 14.11 (C-1), 24.80 (C-2), 22.68 (C-3), 29.50 (C-4), 40.76 (C-5), 65.21 (C-6), 171.10 (C-7), 29.67 (C-8), 20.79 (C-9), 124.75 (C-10), 118.95 (C-11), 132.65 (C-12). EI-MS m/z: 390.3 (M+), 279.2, 167.1, 149.1, 113.2, 71.1. Anhydrosophoradiol-3-acetate (2). White crystals, mp 233–234 C. 1H NMR (400 MHz, CDCl3, , ppm, J/Hz): 2.01 (2H, d, J = 11.5, H-1), 1.67 (2H, s, H-2), 4.50 (1H, t, J = 11.6, H-3), 1.67 (1H, s, H-5), 1.66 (2H, s, H-6), 1.65 (1H, s, H-7), 2.00 (1H, s, H-9), 1.92 (2H, m, H-11), 5.12 (1H, t, J = 3.5, H-12), 1.90 (2H, m, H-15), 1.97 (2H, d, J = 11.5, H-16), 1.89 (2H, m, H-19), 5.18 (1H, t, J = 3.5, H-21), 5.34 (1H, t, J = 3.5, H-22), 1.25 (3H, s, H-23), 1.13 (3H, s, H-24), 1.06 (3H, s, H-25), 0.98 (3H, s, H-26), 0.97 (3H, s, H-27), 0.91 (3H, s, H-28), 0.87 (3H, s, H-29), 0.86 (3H, s, H-30), 2.04 (3H, s, CO-CH3). 13C NMR (150 MHz, CDCl3, , ppm): 28.1 (C-1), 23.4 (C-2), 81.0 (C-3), 28.1 (C-4), 55.3 (C-5), 18.2 (C-6), 29.7 (C-7), 39.6 (C-8), 47.7 (C-9), 28.7 (C-10), 23.6 (C-11), 122.5 (C-12), 143.7 (C-13), 40.0 (C-14), 32.9 (C-15), 38.5 (C-16), 36.8 (C-17), 42.1 (C-18), 41.5 (C-19), 41.5 (C-20), 139.6 (C-21), 124.3 (C-22), 23.2 (C-23), 16.9 (C-24), 16.7 (C-25), 17.5 (C-26), 17.6 (C-27), 23.6 (C-28), 21.4 (C-29), 21.3 (C-30), 15.7 (CO-CH3), 171.0 (CO-CH3). EI-MS m/z: 466.4 (M +), 443.3, 409.3, 391.3. On comparison with the literature, they were identified as di-(2-ethylhexyl)phthalate (1) [15] and anhydrosophoradiol3-acetate (2) [16]. Di-(2-ethylhexyl)phthalate is a synthetic plasticizer, and several reports on its isolation from different medicinal plants have appeared in the literature [15, 17, 18]. The effective presence of di-(2-ethylhexyl)phthalate, not as a contaminant from solvents, was confirmed by analyzing the ethyl acetate used for isolation. In addition, the flowers were not conserved in plastic bags, so these could be discounted as a source of di-(2-ethylhexyl) phthalate.

Antioxidant, cytotoxic and antineoplastic effects of Carissa carandas Linn. leaves

For scientific clarification of some traditional uses, this study was designed to explore the antioxidant, cytotoxic and antineoplastic properties of leaf extract of Carissa carandas Linn., a traditional medicinal plant of Bangladesh. The methanol extract of Carissa carandas leaves (MELC) was applied on DPPH and ABTS experiments to determine its antioxidant activity. In vitro the cytotoxic effect of MELC was evaluated against colonic adenocarcinoma cell lines (SW-480 and SW-48) whereas in vivo its antineoplastic property was tested against Ehrlich ascites carcinoma (EAC). The DPPH and ABTS assays revealed the antioxidant activity of MELC with IC50 10.5±1.2 and 1.75±0.3μg/ml that was comparable to L-ascorbic acid. In vitro cytotoxic study, MELC reduced the viability of adenocarcinoma cells in dose dependent manner and in vivo, administration of MELC (25mg/kg) resulted in a significant (p<0.05) decrease in viable EAC cell count thereby increasing the life span of the EAC cell bearing mice. Restoration of hematological parameters such as red blood cells (RBC), hemoglobin and white blood cells (WBC) to normal levels in MELC-treated mice was also observed. Moreover, treatment with MELC induced apoptosis of EAC cells as observed in fluorescence microscopic view of DAPI (4,6-diamidino-2-phenylindole) stained cells and also increased p53 gene expression MELC-treated cells in respect to untreated EAC control. In addition, the MELC was rich in polyphenol content and its GC-MS chromatogram confirmed the presence of some compounds all of which showed anticancer and cytotoxic activities in previous studies. In a word, this study supports the use of Carissa carandas in traditional medicine as well as highlights the need to further explore the potentials of MELC as an antineoplastic agent.