Browsing by Author "Mulhovo, Silva"
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- Antimycobacterial evaluation and preliminary phytochemical investigation of selected medicinal plants traditionally used in MozambiquePublication . Luo, Xuan; Pires, David; Aínsa, José; Gracia, Begoña; Mulhovo, Silva; Duarte, Aida; Anes, Elsa; Ferreira, Maria José UmbelinoEthnopharmacological relevance Several medicinal plants are traditionally used in Mozambique to treat tuberculosis and related symptoms. Aims of the study It was aimed to assess the in vitro antimycobacterial activity of crude extracts from fifteen medicinal plants and to reveal main classes of compounds which may account for the activity of extracts. Methods and materials The plant materials were sequentially extracted by n-hexane, dichloromethane, ethyl acetate, and 70% ethanol. Decoction of each plant material was also prepared according to traditional use. Broth microdilution method was employed to screen extracts against two mycobacterial species: Mycobacterium smegmatis ATCC 607 and Mycobacterium tuberculosis H37Rv. The extracts with minimum inhibitory concentration(s) (MIC) below 125 μg/mL were considered active and further tested against different mycobacterial species and strains, namely Mycobacterium tuberculosis H37Ra, Mycobacterium bovis BCG ATCC 35734, Mycobacterium smegmatis mc2 155, Mycobacterium avium DSM 44156 and DSM 44157. Cytotoxic effect was evaluated against human macrophages from the monocytic THP-1 cells. Main classes of compounds in these active extracts were proposed from their 1H NMR spectroscopic characterizations. Results n-Hexane extracts of Maerua edulis and Securidaca longepedunculata, ethyl acetate extract of Tabernaemontana elegans and dichloromethane extract of Zanthoxylum capense were found to possess considerable activity against Mycobacterium bovis BCG and Mycobacterium tuberculosis H37Ra with MIC 15.6–62.5 μg/mL. Tabernaemontana elegans ethyl acetate extract displayed strong activity against Mycobacterium tuberculosis H37Rv (MIC 15.6 μg/mL). Except for Tabernaemontana elegans ethyl acetate extract which presented potent cytotoxic effects in THP-1 cells (IC50 < 4 μg/mL), the other three plant extracts showed moderate to none toxicity. Based on 1H NMR spectroscopic analysis, major components in both Maerua edulis and Securidaca longepedunculata n-hexane extracts were linear chain unsaturated fatty acids. Zanthoxylum capense dichloromethane extract contained more complex constituents (mostly phenolic compounds). In the most potent extract, Tabernaemontana elegans ethyl acetate extract, the prominent compounds were identified as indole alkaloids. Conclusions The pronounced antimycobacterial activity of the medicinal plants Maerua edulis, Securidaca longepedunculata, Zanthoxylum capense, and Tabernaemontana elegans suggested that they might provide compounds which could be potential anti-TB drug leads.
- Cucurbitane-Type Triterpenoids from the African Plant Momordica balsaminaPublication . Ramalhete, Catia; Mansoor, Tayyab A.; Mulhovo, Silva; Molnar, Joseph; Ferreira, Maria-Jose U.Phytochemical investigation of the aerial parts of Momordica balsamina led to the isolation of five new cucurbitane-type triterpenoids (1-5) and two known analogues (6, 7). Their structures were elucidated on the basis of spectroscopic methods including 2D NMR experiments (COSY, HMQC, HMBC, and NOESY). The new compounds feature unusual oxidation patterns in the cucurbitane skeleton, such as at C-29 (1-3) and C-12 (4, 5). Compounds 1-4, 6, and 7 were evaluated for in vitro cytotoxicity against human breast cancer cells (MCF-7), using the MTT assay.
- Evaluation of Cucurbitane-type Triterpenoids from Momordica balsamina on P-Glycoprotein (ABCB1) by Flow Cytometry and Real-time FluorometryPublication . Spengler, Gabriella; Ramalhete, Catia; Martins, Marta; Martins, Ana; Serly, Julianna; Viveiros, Miguel; Molnar, Joseph; Duarte, Noelia; Mulhovo, Silva; Ferreira, Maria-Jose U.; Amaral, LeonardBackground: Cancer cells become refractory to chemotherapy as a consequence of their overexpressing ABC transporters that extrude not only the therapeutic agent but other unrelated compounds such as chemotoxins and biocides before they can reach their intended targets. A compound that can inhibit the activity of these transporters may find use as an adjunct to chemotherapy that had been rendered ineffective. Materials and Methods: Four curcubitane-type triterpenes isolated from Momordica balsamina Linn. (Cucurbitaceae), a plant from Mozambique were evaluated for their inhibition of the ABC transporter P-glycoprotein coded by the human ABCB1 gene transfected into mouse lymphoma cells. The evaluation was conducted by flow cytometry using rhodamine 123 and real-time fluorometry assessing accumulation of ethidium bromide (EB) on a real-time basis. Results: Among the compounds isolated, the most active was 7-methoxycucurbita-5,24-diene-3 beta,23(R)-diol, which inhibited the efflux of ethidium bromide (EB) and rhodamine 123 from the ABCB1-transfected mouse lymphoma cell. Conclusion: Real-time fluorometry replicated the flow cytometric results with significant advantages for the evaluation of efflux pump inhibitors. The substitution of side groups on the cucurbitane skeleton appears to be significant in the inhibition of ABCB1 activity.. - Fundacao para a Ciencia e a Tecnologia [FCT], Portugal [SFRH/BPD/34578/2007, SFRH/BD/22321/2005, SFRH/BD/19445/2004]; Luso-Hungarian Cooperation [FCT/DREBM 00542, OMFB-00389/2008, PT-13/2007]. - G. Spengler, C. Ramalhete and A. Martins were supported by grants SFRH/BPD/34578/2007, SFRH/BD/22321/2005 and SFRH/BD/19445/2004 (Fundacao para a Ciencia e a Tecnologia [FCT], Portugal), respectively and by Luso-Hungarian Cooperation FCT/DREBM 00542, OMFB-00389/2008, PT-13/2007.
- Induction of apoptosis in HuH-7 cancer cells by monoterpene and beta-carboline indole alkaloids isolated from the leaves of Tabernaemontana elegansPublication . Mansoor, Tayyab A.; Ramalho, Rita M.; Mulhovo, Silva; Rodrigues, Cecilia M. P.; Ferreira, Maria Jose U.Three known (1-3) and a novel (4) monoterpene indole alkaloids have been isolated from the methanol extract of leaves of Tabernaemontana elegans and their structures were elucidated by a series of spectroscopic experiments, involving NMR, MS, UV, and IR techniques. The isolated monoterpene indole alkaloids along with previously described beta-carbolines (5-7) from the same specimen were studied for their apoptosis induction activity in human hepatoma HuH-7 cells. Methodology for apoptosis induction studies included cell viability assays, nuclear morphology assessments, and general caspase-3-like activity assays. The monoterpene indole alkaloids, tabernaemontanine (1) and vobasine (3) showed the most promising apoptosis induction pro. le in HuH-7 cells. (C) 2009 Elsevier Ltd. All rights reserved.. - FCT, Portugal [BPD/30492/2006]. - This study was supported by a fellowship from FCT, Portugal reference number BPD/30492/2006). The authors wish to thank Dr. Teresa Vasconcelos of Instituto Superior de Agronomia, Universidade de Lisboa, Portugal for the taxonomic work on the plant material and also Dr. Catarina Arruda and Dr. Guedes de Sousa, from the Portuguese Embassy in Mozambique, as well as the Portuguese Of. ce of International Affairs for plant transport.
- New potent P-glycoprotein modulators with the cucurbitane scaffold and their synergistic interaction with doxorubicin on resistant cancer cellsPublication . Ramalhete, Catia; Molnar, Joseph; Mulhovo, Silva; Rosario, Virgilio E.; Ferreira, Maria-Jose U.The novel cucurbitacins, balsaminagenin A and B (1-2) and balsaminoside A (3) and the know cucurbitacin karavelagenin C (4), together with five new mono or diacylated derivatives (5-9) of karavelagenin C were evaluated for multidrug resistance reversing activity on human MDR1 gene transfected mouse lymphoma cells. Compounds 2-6 exhibited a strong activity compared with that of the positive control, verapamil. Structure-activity relationships are discussed. Moreover, in the checkerboard model of combination chemotherapy, the interaction between doxorubicin and compounds 2-5 synergistically enhanced the effect of the anticancer drug. Compounds 1-4 were isolated from the aerial parts of Momordica balsamina L. The structures of the compounds were established on the basis of spectroscopic methods including 2D NMR experiments (COSY, HMQC, HMBC and NOESY). (C) 2009 Elsevier Ltd. All rights reserved.. - Science and Technology Foundation, Portugal (FCT) [SFRH/BD/22321/2005]; Szeged Foundation for Cancer Research. - The Science and Technology Foundation, Portugal (FCT, grant SFRH/BD/22321/2005) and the Szeged Foundation for Cancer Research supported this work. The authors thank Mrs. Vigyikan Varady Aniko for technical assistance with the tissue cultures, and also Dr. Catarina Arruda and Dr. Guedes de Sousa, from the Portuguese Embassy in Mozambique, as well as the Portuguese Office of International Affairs for plant transport.
- Tabernines A-C, beta-Carbolines from the Leaves of Tabernaemontana elegansPublication . Mansoor, Tayyab A.; Ramalhete, Catia; Molnar, Joseph; Mulhovo, Silva; Ferreira, Maria Jose U.Three novel beta-carboline indole alkaloids (1-3) have been isolated from a MeOH extract of the leaves of Tabernaemontana elegans. The structures were established by means of spectroscopic techniques including 2D NMR experiments. Compounds 1 and 2 contain a two-carbon unit, attached to a structurally related beta-carboline skeleton, as part of an additional six-membered ring in 1 and a seven-membered ring in 2. To the best of our knowledge, this is the first report of beta-carboline indole alkaloids from the genus Tabernaemontana. Compounds 1-3 were evaluated for their ability to modulate multidrug resistance in mouse lymphoma cell lines. Compounds 1 and 3 exhibited a weak activity.. - FCT, Portugal [BPD/30492/2006]. - This study was supported by a fellowship from FCT, Portugal (reference number BPD/30492/2006). The authors wish to thank Dr. T. Vasconcelos of Instituto Superior de Agronomia, Universidade de Lisboa, Portugal, for the taxonomic work on the plant material and also Dr. C. Arruda and Dr. G. de Sousa, from the Portuguese Embassy in Mozambique, as well as the Portuguese Office of International Affairs for plant transport.