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Objective: The present study addresses the effect of water deficit stress on the antimicrobial capacity of alfalfa (Medicago sativa) plants.Methods: Methanolic extracts of alfalfa plants grown in different soil types, varying in sand proportion, either alone or combined with various levels of water regimes were assessed for antibacterial and antifungal activities following cup plate method. The phytochemical profiles of plant extracts were also qualitatively screened using appropriate chemical reagents. Moreover, data were intensively processed via two different statistical designs. For centuries, desertification and drought could affect many parts of the world with remarkable negative impact on land productivity. Almost every year, new sectors of the earth are hit by theses stresses bringing about paramount disturbance in agricultural yield [1]. Therefore, many studies have been registered to estimate the consequences of such constraints on plant performance, the response of plants to these devastating factors and also the techniques that could be employed to ameliorate their adverse effects. Nevertheless, it is to somewhat scarce to find studies on how to take advantage from these stressful conditions that threaten vast tracts of ecosystems. ResultsFor a known medicinal plant species, certain molecules with pharmacological activity may be over-synthesized when it is grown under a new set of environmental conditions, and this would elucidate the improvement of its beneficial effects under stress. In this connection, the levels of bioactive phytochemicals were documented to fluctuate with the environmental conditions [2]. Generally, comparative analyses manifested that the content of various secondary metabolites in plants suffering water shortage is higher than that in their synonyms growing under optimum circumstances [3].The failure of some available antibiotics produced by pharmacological industries to combat some pathogenic microbes, along with the baleful side effects of antibiotic overuse and misuse have forced researchers to investigate the antimicrobial activity of medicinal plants [4]. Alfalfa (Medicago sativa L., family Fabaceae) is a perennial herb with seeds that have long been used in traditional medicine for prevention and cure of various ailments [5]. However and up to our knowledge, few studies scrutinizing the antimicrobial capacity of alfalfa vegetative parts can be recorded [6].Therefore, the present study aims at exploring stress utilization as an effectual simple, low-cost and low-risk strategy to promote alfalfa efficacy as a medicinal plant. In a trial to maximize its antimicrobial efficiency, alfalfa plants would be grown with little water supply employed to different levels either alone or combined with elevated sand proportion in the growing soil.Seeds of alfalfa (Medicago sativa L., cultivar Nubaria 1) were obtained from Al Nubaria Agricultural Organization, El Biheera Governorate, Egypt. The seeds were sown in 3 groups of pots packed with clay and sand mixed to obtain 3 type...

Medicinal plants are leading source of phytochemicals. A pot experiment was designed to evaluate the effect of various water regimes (33, 67 and 100% watering) on the ability of alfalfa plants grown in soils with different texture (33, 67 and 100% sand) to synthesize phenolics, non-photosynthetic pigments, vitamins and minerals. Under drought, the amount of total phenols, saponins, tannins, flavonoids and alkaloids increased with the maximum content of total phenols, tannins and flavonoids recorded for plants in soil with 67% sand. For saponins, 33% sand caused the highest values, while alkaloids increased with increasing sand proportion. Water stress also increased the amount of anthocyanins, lycopene and β-carotene. With adequate irrigation, soil with 33% sand caused the highest amount of these pigments while under drought; their values fluctuated among the three soil types. Moreover, the amount of vitamin C, B1 and B2 increased under water deficit; and their amount increased with increasing sand. Furthermore, the amount of sodium, potassium and calcium increased with drought; while the reverse was recorded for magnesium and phosphorus with the maximum titers of all the addressed elements in plants grown in 100% sand. Thence, little water availability may be an efficient technique invigorating alfalfa medicinal efficacy.