A Phytochemical Study and Biological Activity of Some Citrus Species Growing in Egypt

This study revealed that the total extracts, fractions, pure compounds and essential oils obtained from both species possessed antioxidant activity by scavenging DPPH free radical Neohesperidin which was isolated from the peel of C. pyriformis Hassk and C. jambhiri Lush. demonstrated stronger activity than hesperidin. Polymethoxylated flavonoids which isolated from petroleum ether fraction of peel of rough lemon showed higher IC50 but these compounds together in the fraction showed synergistic effect.It was found that, the essential oil from C. pyriformis Hassk showed strong antioxidant in comparison with the other oil from C. jambhiri Lush.Chapter II: Inhibition of 5-lipoxygenase by essential oils, extracts and fractions.The 5-LOX assay of essential oils, total extracts and different fractions of C. jambhiri Lush. and C. pyriformis Hassk was studied.Citrus essential oils demonstrated a very good activity against 5-LOX. There is a good correlation between the activities of d-limonene with those of citrus oils evaluated. This should not be surprising since d-limonene is the main component of C. jambhiri Lush. and C. pyriformis oils. Moreover, the petroleum ether fraction obtained from both species showed higher activity compared with the other fractions.Chapter III: In vitro antitrypanosomal activity using resazurin dye.This study was applied on the total methanol extracts of the peel of C. jambhiri and C. pyriformis, hesperidin from ethyl acetate of C. jambhiri and neohesperidin from C. pyriformis and essential oils from both species. It was found that, the essential oils of both species showed substantial activity against Trypanosoma brucei brucei compared with the other tested samples.Chapter IV: Antimicrobial Activity.The essential oils of both species showed antimicrobial activity against all tested Gram (+) bacteria and antifungal activity against all tested strains. The oils possess no activity against Gram (-) strains except Pseudomonas fluorescens.Chapter V: MDR Reversal and cytotoxicity by secondary metabolites from C. jambhiri and C. pyriformis.It is confirmed during this study that Citrus compounds can inhibit p-gp dependent efflux and lead to accumulation of antitumor drug inside tumor cell.Most of the compounds especially polymethoxyflavones exhibited cytotoxicity against different cell lines.In conclusion:The biological studies in this work (part II) represent the first time for C. jambhiri and C. pyriformis.Concerning the MDR reversal, this study demonstrates that some Citrus compounds are good substrates of p-gp. Since they show a low cytotoxicity they could be considered as a promising lead compounds for the design of more efficient MDR chemosensitizers or reversal agents.Recommendation, daily intake of Citrus fruits protects human body from chronic disease.