POLYPHENOLIC CONTENTS, ANTIOXIDANT AND ANTIBACTERIAL ACTIVITIES OF AQUEOUS EXTRACTS OF Eucalyptus globulus L. and Trigonella foenum-greacum L.
In Algeria, several medicinal plants from different family have been used as traditional medicines, where they are prepared as decoctions, and some are eaten as salads. Two medicinal plants were screened namely: Eucalyptus globulus L. and Trigonella foenum-greacum L. belongs to the family Myrtaceae and Fabaceae respectively; for evaluation of free radical scavenging and antibacterial activities of the aqueous extract (EGAE, TFAE) of the leaves and seeds of sample plants. Antioxidant activity was assessed using the DPPH test. Moreover, the antibacterial effect of extracts was evaluated according to the agar disk diffusion method against three bacterial strains. Quantitative estimation of total polyphenols, flavonoid showed that the extracts were rich in these compounds (280.63 µg EAG/mg of extract; 37.28 µg EQ/mg of the extract); (272.64±0.09 µg EAG/mg of the extract; 95.85±0.007 µg EQ/mg of the extract) respectively, with a yield of 8.63% and 55.24%, respectively. Furthermore, the extracts showed a very strong anti-radical activity against the radical DPPH even greater than that of BHT (IC50=18.9±1.5 µg/ml; 3.4±0.3 µg/ml, respectively against BHT: IC50=5.7±1.2 µg/ml). The results revealed that extracts showed antibacterial activity against Gram-positive bacteria of varying degrees, whereas there is no obvious effect on Gram-negative bacteria. In conclusion, the aqueous extract of these plants has excellent antioxidant activity and a strong antibacterial effect; these plants may also be subjected to the isolation of therapeutic antimicrobials and further pharmacological assessment.