Abstract
Water hyacinth, Eichhornia crassipes (Mart) Solms, originating in the amazonian basin, is a warm water aquatic plant. Water hyacinth is considered one of the most productive plants on earth and, accordingly, is considered one of the top ten world's worst weeds. Water hyacinth spread to other tropical and subtropical regions by humans. It invaded about 62 countries in Africa, Asia and North America, and propagated extremely serious ecological, economical and social problems in the region between 40 degrees north and 45 degrees south. The dense weed of water hyacinth forms dense monocultures that can threaten local native species diversity and change the physical and chemical aquatic environment, thus altering ecosystem structure and function by disrupting food chains and nutrient cycling. We have separated and identified nine active fractions from water hyacinth and showed their promising therapeutic activities. Several compounds (alkaloid, phthalate derivatives, propanoid and phenyl derivatives) were identified in the extract of water hyacinth.
Key words: water hyacinth, antimicrobial, anticancer, active compounds
Water Security and Eichhornia crassipes (Mart) Solms in the Nile Basin
Water hyacinth, Eichhornia crassipes (Mart) Solms, originated in amazonian basin, is a warm water aquatic plant (Fig. 1). Water hyacinth is considered one of the most productive plants on earth and accordingly is considered one of the top 10 world's worst weeds. Water hyacinth spread to other tropical and subtropical regions by humans. It invaded about 62 countries in Africa, Asia, North America and propagated extremely serious ecological, economical and social problems in the region between 40 degree north and 45 degree south. The dense weed of water hyacinth forms dense monocultures that can threaten local native species diversity and change the physical and chemical aquatic environment, thus altering ecosystem structure and function by disrupting food chains and nutrient cycling. Its vast growth consumes huge quantities of nutrients, favoring its growth over other aquatic species. Decomposition of dead individuals released nutrients to water leading to fresh water quality deterioration, threatening human health. Dense mats of water hyacinth can lower dissolved oxygen levels in water bodies leading to reduction of aquatic fish production. Water hyacinth is very efficient in taking up Calcium, Magnesium, Sulfur, Ferric, Manganese, Aluminum, Boron, Cupper, Molybdenum, Zinc, Nitrogen, Phosphorus and Potassium, favoring its growth over other aquatic species. In the summer season when temperature exceeded 35°C and high solar radiation with long light duration, Eichhornia grows faster with rapid spread in the Egyptian water bodies and serious problems occurred.
Figure 1.
Water hyacinth single (A), and in the form of dense mat (B).
Newly Identified Compounds from Eichhornia crassipes (Mart) Solms
In our laboratory, we are adopting the idea of making use out of this ecologic crisis to potential therapeutic remedy. We have separated and identified nine active fractions from water hyacinth (Fig. 2) and showed their promising therapeutic activities. Several compounds (alkaloid, phthalate derivatives, propanoid and phenyl derivatives) were identified in the extract of water hyacinth. This preliminary information may encourage a country-wide project for not only collecting and getting rid of water hyacinth, but also making a pharmaco-economic value of this aquatic weed. We have sequential data published revealing the high potency of water hyacinths as antibacterial, antifungal, antioxidants and anticancer remedy. The crude extract per se represents stable material, favorable economic and industrial value for the production of commercial product for clinical use. On the other hand, the use of crude extract in therapy represents a challenge in terms of mass production quality control and assurance.1,3
Figure 2.
Chemical structure of newly identified bioactive compounds in Water hyacinth.
Potential Anti-Bacterial Effects
Crude extract of Eichhornia crassipes and several fractions showed moderate activities against Gram positive and Gram negative bacteria. It was about 50% as potent as tetracycline. A diversity of antibacterial activities was found attributed to different isolated fractions. Different combinations of these fractions showed similar, slightly lower or higher efficacy compared to the crude extract and in strain dependent (E. coli and S. faecalis). We have suggested that the crude extract contained different antibacterial substances with variable efficiencies and mode of actions which may act antagonistically or synergistically in inhibition bacterial growth.1
Potential Anti-Fungal Effects
Antifungal activities of extracts (crude and different fractions) were manifested only against C. albicans (yeast). Both A. flavus and A. niger were highly resistant to all fractions and the crude extracts of Eichhornia crassipes. Some fractions exhibited promising activities against Candida albicans.1
Potential Anti-Oxidant Effects
The DPPH scavenging activity was performed to test the antioxidant properties of the crude extract of Eichhornia crassipes and its isolated fractions. The crude extract showed the highest antioxidant activity while some compounds recorded more or less lower or comparable activities. Many fractions showed very close antioxidant effects with IC50 ranged between 97.0 ± 5.4 and 97.4 ± 2.7 µg/ml.
The antioxidant activity of active ingredients separated from E. crassipes may be attributed to the presence of hydroxyl group and unsaturated bonds in the chemical structure of its isolated compounds showing high free radicals scavenging ability.1,3
Potential Anticancer Effects
Concerning the anticancer activity, the crude extract also showed the highest effect compared to all isolated compounds against several tumor types (Fig. 3). Some fractions exhibited selective very potent anticancer activity against liver cancer cell line while other fractions exhibited high anticancer activity against hormone dependent tumor types (cervix and breast cancers).
Figure 3.
Clinically isolated leukemia cells (A), and treatment with crude extract for 24 h (B).
The cytotoxicity parameter, IC50 was calculated using Emax model. Some isolated compounds showed potency with IC50 as low as 1.6 ± 0.5 µg/ml. It's worth mentioning, that the higher potency of the crude extract against cancer cell lines relative to all fractions from the same extract, might be attributed to auto-synergistic effect of these fractions within the same extract. Further studies are recommended to identify potential interference between the isolated potent fractions.2,3
Acknowledgements
This research was funded by grants from both the National CFIDS Foundations Inc, Needham, MA 02492-3931, USA; and STDF (ID 312), Ministry of Higher Education and State for Scientific Research, Egypt. We would like to thank Mr. Abdel-Hay G. Abu-Hussein, Department of biotechnology, Faculty of Agriculture Research Park, Cairo University, Cairo, Egypt, for his technical support.
References
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